Comparison of Outcomes of Primary Anterior Chamber Versus Secondary Scleral-Fixated Intraocular Lens Implantation in Complicated Cataract Surgeries TOMMY C.Y. CHAN, JASMINE K.M. LAM, VISHAL JHANJI, AND EMMY Y.M. LI PURPOSE: To compare the outcome of primary anterior chamber vs secondary scleral-fixated intraocular lens (IOL) implantation in complicated cataract surgeries. DESIGN: Retrospective, comparative study. METHODS: A consecutive series of complicated cataract surgeries with primary anterior chamber (ACIOL) or secondary scleral-fixated IOL implantation from January 1, 2004 to December 31, 2009 was analyzed. Main outcome measures included the postoperative best-corrected visual acuity (BCVA) and postoperative complications. RESULTS: There were 89 eyes in the primary ACIOL group and 74 eyes in the secondary scleral-fixated IOL group. The mean follow-up duration was 64.1 ± 36.7 months. The mean postoperative logarithm of minimal angle of resolution (logMAR) BCVA at 1 year was 0.32 ± 0.54 and 0.34 ± 0.21 in the primary ACIOL group and the secondary scleral-fixated IOL group, respectively (P [ .734). The mean latest logMAR BCVA was 0.68 ± 0.54 and 0.61 ± 0.47 in the primary ACIOL group and the secondary scleral-fixated IOL group, respectively (P [ .336). The primary ACIOL group had more early postoperative complications (P < .001). No difference in late postoperative complications was observed between the 2 groups (P [ .100). Regression analysis showed that primary ACIOL and secondary scleral-fixated IOL implantation had similar latest postoperative logMAR BCVA (P [ .927), while the presence of late complications was associated with a worse final visual outcome (P [ .000). CONCLUSIONS: This study shows that there are no longterm differences in the visual outcomes and complication profiles after primary ACIOL or secondary scleral-fixated IOL implantation in a complicated cataract operation when capsular support is inadequate. (Am J Ophthalmol 2015;159:221–226. Ó 2015 by Elsevier Inc. All rights reserved.)
Accepted for publication Oct 14, 2014. From Hong Kong Eye Hospital (T.C.Y.C., J.K.M.L., E.Y.M.L.); and Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong (T.C.Y.C., J.K.M.L., V.J., E.Y.M.L.), Hong Kong, China. Inquiries to Emmy Y.M. Li, Hong Kong Eye Hospital, 147K Argyle Street, Kowloon, Hong Kong SAR, China; e-mail: [email protected] 0002-9394/$36.00 http://dx.doi.org/10.1016/j.ajo.2014.10.016
Ó
2015 BY
C
ATARACT EXTRACTION IS THE MOST COMMONLY
performed ophthalmic surgery. Implantation of posterior chamber intraocular lens (IOL) is always desirable in the presence of sufficient capsular support.1 In complicated cataract surgery when capsular support is inadequate for IOL implantation in the capsular bag or at the ciliary sulcus, the surgeon needs to decide whether to implant an anterior chamber IOL (ACIOL) or a scleralfixated IOL. With the development of the open-loop haptic design, ACIOL regained its popularity because of the ease of insertion and better safety profile.2,3 Primary ACIOL implantation has been compared to primary scleral-fixated IOL implantation in a study from our hospital showing better visual outcomes and noninferior complication profiles.4 On the contrary, secondary ACIOL and scleral-fixated IOL implantation were reported to have similar visual outcomes and late complications.5–8 In our setting, surgeons often choose between primary ACIOL or secondary scleral-fixated IOL implantation when cataract surgery is complicated owing to the loss of posterior capsule. Primary scleral-fixated IOL is not a common choice, since not all surgeons are familiar with the surgical technique. Moreover, the surgical slot is often tightly packed, making prolonged operation logistically difficult. The main advantage of primary ACIOL insertion is the avoidance of a second operation. However, there are potential risks of corneal edema and intraocular pressure escalation. On the other hand, secondary scleral-fixated IOL implantation allows for better surgical planning, yet an additional operation is needed. The present study aims to compare the outcomes of primary ACIOL vs secondary scleral-fixated IOL implantation in complicated cataract surgeries.
METHODS THIS IS A RETROSPECTIVE STUDY OF ALL THE CONSECUTIVE
primary ACIOL and secondary scleral-fixated IOL implantation surgeries performed at Hong Kong Eye Hospital from January 1, 2004 to December 31, 2009. Patients were identified by a search from the logbook documenting cataract and IOL surgeries during the study period. The study was
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conducted in accordance with the tenets of the Declaration of Helsinki and was approved by the Institutional Review Board of the Kowloon Central Cluster, Hospital Authority, Hong Kong. Exclusion criteria included: (1) causes of poor visual function other than cataract, such as amblyopia, macular scar, and optic atrophy before cataract surgery; (2) pathologic features that would dictate the choice of IOL implantation, such as uveitis and glaucoma; (3) combined surgery, including corneal surgery, glaucoma surgery, and pars plana vitrectomy; and (4) postoperative follow-up of less than 12 months. Patient demographics, follow-up duration, type of cataract operation planned, type of IOL implanted, postoperative best-corrected visual acuity (BCVA) and refraction at 1 year after surgery, latest BCVA, and postoperative complications were collected from each case record. Surgical technique for IOL implantation in both groups was the same as previously described.4 In the primary ACIOL group, Pharmacia 351C lenses (Pharmacia International, Capelle aan den Ijssel, The Netherlands) or Bausch & Lomb S112UV lenses (Bausch & Lomb Inc, New York, New York, USA) were implanted. Both lenses are single-piece polymethyl methacrylate (PMMA), open-loop, semi-flexible lens with 4-point fixation. In the secondary scleral-fixated IOL group, Alcon CZ70BD lenses (Alcon Laboratories, Forth Worth, Texas, USA), a single-piece PMMA lens with eyelets, were used for all secondary scleral-fixated IOL implantations in the current study. Statistical analyses were performed using PASW software version 18.0 (SPSS/IBM Inc, Chicago, Illinois, USA). Descriptive statistics in both treatment groups were reported. Snellen BCVA was converted into logarithm of the minimal angle of resolution (logMAR) units for analysis. Visual acuities of hand movement and light perception were arbitrarily assigned the equivalent of 1.7 and 1.8 logMAR units, respectively.4,9,10 Group means were compared with independent t test. Complication rates were evaluated using x2 test or Fisher exact test. A multiple linear regression model with latest BCVA as the dependent variable was constructed. Collinearity diagnostic, using an averaged variance inflation factor of more than 3 as cutoff, was included. A P value of 30 mm Hg Residual lens material Severe uveitis Fibrin Hyphema Vitreous incarceration at wound site Intraocular lens capture Choroidal detachment Retinal detachment Endophthalmitis Number of eyes with early complications Late complications (after 1 mo) Bullous keratopathy Persistent intraocular pressure >21 mm Hg Vitreous prolapse into anterior chamber Persistent uveitis Intraocular lens decentration Pseudophakic cystoid macular edema Retinal detachment Number of eyes with late complications
1 Anterior Chamber IOL
28 ScleralFixated IOL
89
74
P Value
49 (66.6%) 16 (21.6%) .000 6 (6.7%) 9 (12.2%) .222 11 (12.4%) 8 (10.8%) .783 13 (14.6%) 4 (4.5%) 1 (1.1%) 7 (7.9%) 0 (0.0%)
1 (1.4%) 5 (6.8%) 0 (0.0%) 3 (4.1%) 1 (1.4%)
.003 .515 .364 .323 .268
1 (1.1%) 0 (0.0%) 2 (2.2%) 2 (2.7%) 1 (1.1%) 0 (0.0%) 2 (2.2%) 0 (0.0%) 62 (69%) 29 (39.2%)
.364 .841 .364 .194 .000
11 (12.4%) 8 (10.8%) .783 12 (13.5%) 17 (23.0%) .115 3 (3.4%)
4 (5.4%)
.524
1 (1.1%) 1 (1.1%) 3 (3.4%)
4 (5.4%) 3 (4.1%) 2 (2.7%)
.118 .229 .805
1 (1.1%) 0 (0.0%) .360 23 (25.8%) 28 (37.8%) .100
18 ¼ primary; 28 ¼ secondary; IOL ¼ intraocular lens.
(39.7%) in the primary ACIOL group and the secondary scleral-fixated IOL group, respectively (P < .001). The primary ACIOL group had significantly more transient corneal edema (P < .001) and residual lens material (P ¼ .003) compared to the secondary scleral-fixated IOL group. Late (after 1 month) postoperative complications occurred in 23 of 89 eyes (25.8%) and 28 of 74 eyes (37.8%) in the primary ACIOL group and the secondary scleral-fixated IOL group, respectively (P ¼ .100). There were no differences in each of the late postoperative complications between the 2 groups (P < .115). Early and late postoperative complications are shown in Table 2. Among the cases in which patients suffered from persistently elevated intraocular pressure, 1 eye (1/12; 8.3%) following primary ACIOL insertion needed laser cyclophotocoagulation VOL. 159, NO. 2
(P ¼ 1.000), while 2 eyes (2/17; 11.8%) receiving secondary scleral-fixated IOL placement needed trabeculectomy (P ¼ .485). Suture erosion occurred in only 2 eyes (2/74; 2.7%) with scleral-fixated IOL implanted (P ¼ .118). There were no cases of IOL-pupil capture, IOL dislocation, or endophthalmitis associated with stitch erosion encountered in our patients following scleralfixated IOL implantation. Eyes without long-term complications had better latest BCVA than eyes with complications (P < .001 for both groups). There was no difference in the latest postoperative BCVA (P ¼ .883) and latest Snellen BCVA of 20/40 or better (P ¼ .911) between the 2 groups in the eyes with no late complications. The latest postoperative logMAR BCVA in the eyes with no late complications was 0.48 6 0.30 and 0.49 6 0.33 in the primary ACIOL group and the secondary scleral-fixated IOL group, respectively. On the contrary, the primary ACIOL group had worse postoperative BCVA (P ¼ .031) and latest Snellen BCVA of 20/ 40 or better (P ¼ .023) compared to the secondary scleralfixated IOL in the eyes with late complications. The latest postoperative logMAR BCVA in the eyes with late complications was 1.25 6 0.63 and 0.86 6 0.59 in the primary ACIOL group and the secondary scleral-fixated IOL group, respectively. The types of cataract operation planned were known in 144 eyes, including 87 of 88 eyes (97.8%) and 57 of 74 eyes (77.0%) in the primary ACIOL group and the secondary scleral-fixated IOL group, respectively. There were more cataract operations unidentified in the secondary scleralfixated IOL group because those cases were referred to our hospital for secondary IOL insertion from the private sector. A total of 72 eyes (72/87; 82.8%) in the primary ACIOL group and 34 eyes (34/57; 59.6%) in the secondary scleral-fixated IOL group underwent phacoemulsification (P < .001). Extracapsular cataract extraction was planned in 15 eyes (15/87; 17.2%) and 23 eyes (23/57; 40.4%) in the primary ACIOL group and the secondary scleral-fixated IOL group, respectively (P < .001). Indeed, most cases were converted to extracapsular cataract extraction when there was inadequate capsular support during phacoemulsification. A multiple linear regression model was constructed with the latest logMAR BCVA as the dependent variable and IOL group (primary ACIOL group vs secondary scleralfixated IOL group), age of patient, postoperative logMAR BCVA at 1 year, presence of early postoperative complication, presence of late postoperative complication, and type of cataract operation planned as the independent variables. There was no evidence of correlation or interaction among the variables included in the regression model. The presence of late complication was an independent predictor for poorer logMAR BCVA at the last follow-up (P < .001). None of the other independent variables was significantly associated with the latest logMAR BCVA. The regression model summary for latest logMAR BCVA is
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TABLE 3. Primary Anterior Chamber vs Secondary Scleral-Fixated Intraocular Lens Implantation in Complicated Cataract Surgeries: Postoperative Latest Best-Corrected Visual Acuity Linear Regression Model Summary Dependent Variable
Independent Variable
Unstandardized b Coefficients
Postoperative BCVA
18 anterior chamber or 28 scleral-fixated IOL Age of patient Planned operation BCVA at 1 year Early complications Late complications
0.008 0.003 0.128 0.046 0.111 0.556
95% Confidence Intervals
0.188 to 0.171 0.007 to 0.012 0.314 to 0.058 0.131 to 0.222 0.064 to 0.286 0.380 to 0.731
P Value
.927 .567 .176 .610 .211 .000
18 ¼ primary; 28 ¼ secondary; BCVA ¼ best-corrected visual acuity; IOL ¼ intraocular lens.
TABLE 4. Primary Anterior Chamber vs Secondary Scleral-Fixated Intraocular Lens Implantation in Complicated Cataract Surgeries: Postoperative Latest Best-Corrected Visual Acuity Linear Regression Model Summary Excluding Planned Operation Dependent Variable
Independent Variable
Unstandardized b Coefficients
Postoperative BCVA
18 anterior chamber or 28 scleral-fixated IOL Age of patient BCVA at 1 year Early complications Late complications
0.049 0.003 0.079 0.123 0.542
95% Confidence Intervals
0.104 to 0.203 0.005 to 0.011 0.084 to 0.241 0.029 to 0.276 0.387 to 0.697
P Value
.526 .458 .341 .112 .000
18 ¼ primary; 28 ¼ secondary; BCVA ¼ best-corrected visual acuity; IOL ¼ intraocular lens.
shown in Table 3. Similar results were seen when the type of cataract operation planned was excluded because the cataract was actually extracted differently than planned. The regression model summary with the type of cataract operation excluded among other independent variables is shown in Table 4.
DISCUSSION COMPARISON BETWEEN ACIOL AND SCLERAL-FIXATED IOL
implantation in eyes without adequate capsular support during cataract extraction has been investigated extensively in the last 2 decades. An assessment by the American Academy of Ophthalmology concluded that implantation of ACIOL and scleral-fixated IOL had comparable safety and efficacy profiles in the absence of capsular support.3 Several comparative trials on secondary insertion of these 2 IOL modalities demonstrated similar visual outcomes and complication rates at intermediate-term follow-up period.5–8 In Evereklioglu and associates’ series of 124 eyes with secondary placement of an open-loop ACIOL or scleral-fixated IOL, the 3-year postoperative logMAR BCVA was 0.24 following implantation of ACIOL and 0.20 after implantation of scleral-fixated IOL.7 Complications occurred in 34% and 25% of the eyes implanted with ACIOL and scleral-fixated IOL, respectively. Likewise, Donaldson and associates compared 181 eyes that 224
had implantation of ACIOL and scleral-fixated IOL. The final postoperative logMAR BCVA at 1 year was 0.48 after ACIOL implantation and 0.40 after scleral-fixated IOL implantation.8 Complications were encountered in 68% of eyes in their study. In a previous study performed in our hospital, primary ACIOL implantation showed a better visual outcome compared to primary scleral-fixated IOL implantation.4 Seventy-two percent of eyes implanted with ACIOL and 47% implanted with scleral-fixated IOL achieved a postoperative Snellen BCVA of 20/40 or better at 3 years. The postoperative logMAR BCVA was 0.32 and 0.49, respectively. The complication profile did not differ significantly between the 2 techniques. An earlier retrospective analysis carried out in our hospital demonstrated no difference in BCVA and late complication profiles between primary and secondary scleral-fixated IOL implantation.9 The postoperative logMAR BCVA was 0.50 for primary scleral-fixated IOL implantation and 0.36 for secondary scleral-fixated IOL implantation after a mean follow-up of 19 months. In our setting, when there is a loss of posterior capsule integrity during cataract extraction, surgeons often choose between primary ACIOL or secondary scleral-fixated IOL implantation, taking into consideration the ease of implantation in the former and better surgical planning for the latter. To the best of our knowledge, the current study is the only large-scale direct comparative study between these 2 modalities for an extended follow-up period in the literature.
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The BCVA in the first postoperative year was similar between primary ACIOL and secondary scleral-fixated IOL implantation. This is similar to the BCVA observed in studies comparing primary or secondary implantation of ACIOL and scleral-fixated IOL in the literature.4,7,8 The logMAR BCVA in these studies ranged from 0.24 to 0.48 after ACIOL implantation and from 0.20 to 0.49 after scleral-fixated IOL implantation. Although our final visual outcome observed at 5 years after IOL insertion was inferior to these ranges, there was no significant difference between the 2 modalities. This was further supported by the multiple linear regression analysis, which showed that IOL modality did not affect the latest BCVA. The decrease in BCVA was mainly caused by the development of late complications. The latest BCVA was only affected by the presence of late complications in our patients according to the regression analysis. Future long-term prospective studies with standardized follow-up schedules would help further delineate the changes in visual outcome between these 2 modalities over time. There were no differences in the absolute spherical equivalent and astigmatism between the 2 groups, signifying minimal impact on IOL power selection and IOL centration in both IOL types. Similar to the report by Lee and associates comparing primary and secondary scleral-fixated IOL implantation,9 there were more eyes with early postoperative complications after primary ACIOL implantation in our study. The most common early complication was transient corneal edema, followed by retained lens material. Complicated cataract operation undergoing primary IOL implantation may pose greater stress to the corneal endothelium owing to prolonged surgery. Also, intraoperative corneal edema attributable to additional manipulation and prolonged surgery may hamper the surgeon’s view. This could explain the higher number of early complications following primary ACIOL implantation observed in the current study. On the contrary, there was no difference in the late complications between the 2 groups. There was no difference in the incidence of corneal decompensation following primary ACIOL (12.4%) and secondary scleralfixated IOL (10.8%) implantation. These figures were higher than those in the literature mainly because of the longer follow-up duration in the present study.5–8 This finding was important to our locality because Chinese eyes tend to have a shallow anterior chamber,11 which puts the corneal endothelium at higher risk of decompensation following the placement of an ACIOL.12 Similar to previous studies,4,8,13 the most frequent late complication observed was persistently high intraocular pressure, which was defined as >21 mm Hg for 3 months requiring medical or surgical intervention. No intergroup difference was found. In Kwong and associates’ series, persistently raised intraocular pressure was seen in 13% of eyes, with no difference between the 2 IOL types,4 while 41% of cases in Donaldson and associates’ series suffered from elevated intraocular pressure, with no intergroup VOL. 159, NO. 2
difference.8 Suture erosion occurred in only 2 eyes (2.7%) with scleral-fixated IOL implanted, which was similar to a recent study comparing long-term outcome of scleral-fixated IOL over a similar follow-up duration.10 Other studies have reported variable incidence of complications following scleral-fixated IOL implantation.10,14,15 The complication rates observed in our study were not inferior to those reported in the literature. The multiple linear regression model in our study showed that the latest BCVA was affected significantly by the presence of late postoperative complications. Univariate comparison between complicated and uncomplicated cases also supported a better final visual outcome in eyes that did not have late complications. In addition, we observed that eyes with late complications had significantly worse BCVA after primary implantation of an ACIOL compared to the secondary implantation of a scleralfixated IOL. This may be explained by the different patterns of late complications encountered in each group. Although not statistically significant, there were more eyes with bullous keratopathy, cystoid macular edema, and retinal detachment in the primary ACIOL group. On the other hand, more eyes with secondary scleral-fixated IOL suffered from high intraocular pressure, persistent anterior uveitis, and IOL tilting, which affected vision to a lesser extent. Limitations of the current study include its retrospective nature, with different surgeons performing the operations. Moreover, we did not have corneal endothelial cell density measured. Cystoid macular edema was mostly detected clinically and was confirmed with fluorescent angiography in our patients. We may have underestimated the actual number of cases suffering from this complication compared to previous studies that used optical coherence tomography routinely for better detection of macular pathologies.16,17 In our hospital, decision making by the operating surgeon on the implantation of either an ACIOL or a scleralfixated IOL in the absence of adequate capsular support was not standardized. There was significant difference in age between the 2 groups in this study. The choice of IOL during a complicated cataract surgery is sometimes dictated by the age of the patients, and this was also reflected in our study, with a tendency of primary ACIOL being implanted in older patients. The rationale behind this practice was the presumption that complications of ACIOL develop later, presumably well beyond the life expectancy of the patients.8,18 Despite the discrepancy, age by itself did not significantly affect the final visual outcome according to our multivariate analysis. There were also differences in the proportion of cataract operations planned between the 2 groups. However, the actual method of cataract extraction was often different from planned in a complicated cataract operation, depending on the stage when capsular support was disrupted. Therefore, it did not affect the latest BCVA in our multiple linear regression model.
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In conclusion, our study shows that there are no longterm differences in the visual outcomes and complication profiles after primary ACIOL implantation or secondary scleral-fixated IOL implantation in a complicated cataract operation when capsular support is inadequate. Primary ACIOL implantation allows immediate aphakic correction
without prolonging the complicated operation extensively. It is recommended when the expertise for scleral-fixated IOL is not available or when a patient cannot afford a second surgery. On the other hand, secondary scleral-fixated IOL implantation allows better surgical planning in a more controlled situation.
ALL AUTHORS HAVE COMPLETED AND SUBMITTED THE ICMJE FORM FOR DISCLOSURE OF POTENTIAL CONFLICTS OF INTEREST. The authors indicate no financial disclosures or funding support. Contributions of authors: concept and design (T.C.Y.C., J.K.M.L., V.J., E.Y.M.L.); analysis and interpretation (T.C.Y.C., J.K.M.L., V.J., E.Y.M.L.); writing the article (T.C.Y.C.); critical revision of the article (T.C.Y.C., J.K.M.L., V.J., E.Y.M.L.); final approval of the article (T.C.Y.C., J.K.M.L., V.J., E.Y.M.L.); data collection (T.C.Y.C., J.K.M.L., E.Y.M.L.); provision of materials, patients, or resources (T.C.Y.C., J.K.M.L., V.J., E.Y.M.L.); statistical expertise (T.C.Y.C.); literature research (T.C.Y.C., J.K.M.L., V.J., E.Y.M.L.); and administrative, technical, or logistic support (T.C.Y.C., V.J.).
REFERENCES 1. Collins JF, Gaster RN, Krol WF, Colling CL, Kirk GF, Smith TJ. A comparison of anterior chamber and posterior chamber intraocular lenses after vitreous presentation during cataract surgery: the Department of Veterans Affairs Cooperative Cataract Study. Am J Ophthalmol 2003;136(1):1–9. 2. Dick HB, Augustin AJ. Lens implant selection with absence of capsular support. Curr Opin Ophthalmol 2001;12(1):47–57. 3. Wagoner MD, Cox TA, Ariyasu RG, Jacobs DS, Karp CL. Intraocular lens implantation in the absence of capsular support: a report by the American Academy of Ophthalmology. Ophthalmology 2003;110(4):840–859. 4. Kwong YY, Yuen HK, Lam RF, Lee VY, Rao SK, Lam DS. Comparison of outcomes of primary scleral-fixated versus primary anterior chamber intraocular lens implantation in complicated cataract surgeries. Ophthalmology 2007;114(1):80–85. 5. Lyle WA, Jin JC. Secondary intraocular lens implantation: anterior chamber vs posterior chamber lenses. Ophthalmic Surg 1993;24(6):375–381. 6. Bellucci R, Pucci V, Morselli S, Bonomi L. Secondary implantation of angle-supported anterior chamber and scleral-fixated posterior chamber intraocular lenses. J Cataract Refract Surg 1996;22(2):247–252. 7. Evereklioglu C, Er H, Bekir NA, Borazan M, Zorllu F. Comparison of secondary implantation of flexible open-loop anterior chamber and scleral-fixated posterior chamber intraocular lenses. J Cataract Refract Surg 2003;29(2):301–308. 8. Donaldson KE, Gorscak JJ, Budenz DL, Feuer WJ, Benz MS, Forster RK. Anterior chamber and sutured posterior chamber intraocular lenses in eyes with poor capsular support. J Cataract Refract Surgery 2005;31(5):903–909. 9. Lee VY, Yuen HK, Kwok AK. Comparison of outcomes of primary and secondary implantation of scleral fixated posterior chamber intraocular lens. Br J Ophthalmol 2003;87(12): 1459–1462.
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10. Luk AS, Young AL, Cheng LL. Long-term outcome of scleralfixated intraocular lens implantation. Br J Ophthalmol 2013; 97(10):1308–1311. 11. Leung CK, Palmiero PM, Weinreb RN, et al. Comparisons of anterior segment biometry between Chinese and Caucasians using anterior segment optical coherence tomography. Br J Ophthalmol 2010;94(9):1184–1189. 12. Holt DG, Young J, Stagg B, Ambati BK. Anterior chamber intraocular lens, sutured posterior chamber intraocular lens, or glued intraocular lens: where do we stand? Curr Opin Ophthalmol 2012;23(1):62–67. 13. Krause L, Bechrakis NE, Heimann H, Salditt S, Foerster MH. Implantation of scleral fixated sutured posterior chamber lenses: a retrospective analysis of 119 cases. Int Ophthalmol 2009;29(4):207–212. 14. Vote BJ, Tranos P, Bunce C, Charteris DG, Da Cruz L. Longterm outcome of combined pars plana vitrectomy and scleral fixated sutured posterior chamber intraocular lens implantation. Am J Ophthalmol 2006;141(2):308–312. 15. Ganekal S, Venkataratnam S, Dorairaj S, Jhanji V. Comparative evaluation of suture-assisted and fibrin glue-assisted scleral fixated intraocular lens implantation. J Refract Surg 2012;28(4):249–252. 16. Vukicevic M, Gin T, Al-Qureshi S. Prevalene of optical coherence tomography-diagnosed postoperative cystoid macular oedema in patients following uncomplicated phacoemulsification cataract surgery. Clin Experiment Ophthalmol 2012;40(3):282–287. 17. Major JC Jr, Wykoff CC, Mariani AF, Chen E, Croft DE, Brown DM. Comparison of spectral-domain and timedomain optical coherence tomography in the detection of neovascular age-related macular degeneration activity. Retina 2014;34(1):48–54. 18. Por YM, Lavin MJ. Techniques of intraocular lens suspension in the absence of capsular/zonular support. Surv Ophthalmol 2005;50(5):429–462.
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Biosketch Tommy C.Y. Chan is a Resident in Hong Kong Eye Hospital. He is also the Honorary Clinical Tutor of Department of Ophthalmology and Visual Sciences of the Chinese University of Hong Kong.
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Biosketch Dr Emmy Y.M. Li is the Associate Consultant of the Hong Kong Eye Hospital and Honorary Clinical Assistant Professor of the Department of Ophthalmology and Visual Sciences of the Chinese University of Hong Kong. She is also a council member of the Hong Kong Ophthalmological Society and the Hong Kong Federation of Societies for Prevention of Blindness.
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Accepted for publication Oct 14, 2014. From Hong Kong Eye Hospital (T.C.Y.C., J.K.M.L., E.Y.M.L.); and Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong (T.C.Y.C., J.K.M.L., V.J., E.Y.M.L.), Hong Kong, China. Inquiries to Emmy Y.M. Li, Hong Kong Eye Hospital, 147K Argyle Street, Kowloon, Hong Kong SAR, China; e-mail: [email protected] 0002-9394/$36.00 http://dx.doi.org/10.1016/j.ajo.2014.10.016
Ó
2015 BY
C
ATARACT EXTRACTION IS THE MOST COMMONLY
performed ophthalmic surgery. Implantation of posterior chamber intraocular lens (IOL) is always desirable in the presence of sufficient capsular support.1 In complicated cataract surgery when capsular support is inadequate for IOL implantation in the capsular bag or at the ciliary sulcus, the surgeon needs to decide whether to implant an anterior chamber IOL (ACIOL) or a scleralfixated IOL. With the development of the open-loop haptic design, ACIOL regained its popularity because of the ease of insertion and better safety profile.2,3 Primary ACIOL implantation has been compared to primary scleral-fixated IOL implantation in a study from our hospital showing better visual outcomes and noninferior complication profiles.4 On the contrary, secondary ACIOL and scleral-fixated IOL implantation were reported to have similar visual outcomes and late complications.5–8 In our setting, surgeons often choose between primary ACIOL or secondary scleral-fixated IOL implantation when cataract surgery is complicated owing to the loss of posterior capsule. Primary scleral-fixated IOL is not a common choice, since not all surgeons are familiar with the surgical technique. Moreover, the surgical slot is often tightly packed, making prolonged operation logistically difficult. The main advantage of primary ACIOL insertion is the avoidance of a second operation. However, there are potential risks of corneal edema and intraocular pressure escalation. On the other hand, secondary scleral-fixated IOL implantation allows for better surgical planning, yet an additional operation is needed. The present study aims to compare the outcomes of primary ACIOL vs secondary scleral-fixated IOL implantation in complicated cataract surgeries.
METHODS THIS IS A RETROSPECTIVE STUDY OF ALL THE CONSECUTIVE
primary ACIOL and secondary scleral-fixated IOL implantation surgeries performed at Hong Kong Eye Hospital from January 1, 2004 to December 31, 2009. Patients were identified by a search from the logbook documenting cataract and IOL surgeries during the study period. The study was
ELSEVIER INC. ALL
RIGHTS RESERVED.
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conducted in accordance with the tenets of the Declaration of Helsinki and was approved by the Institutional Review Board of the Kowloon Central Cluster, Hospital Authority, Hong Kong. Exclusion criteria included: (1) causes of poor visual function other than cataract, such as amblyopia, macular scar, and optic atrophy before cataract surgery; (2) pathologic features that would dictate the choice of IOL implantation, such as uveitis and glaucoma; (3) combined surgery, including corneal surgery, glaucoma surgery, and pars plana vitrectomy; and (4) postoperative follow-up of less than 12 months. Patient demographics, follow-up duration, type of cataract operation planned, type of IOL implanted, postoperative best-corrected visual acuity (BCVA) and refraction at 1 year after surgery, latest BCVA, and postoperative complications were collected from each case record. Surgical technique for IOL implantation in both groups was the same as previously described.4 In the primary ACIOL group, Pharmacia 351C lenses (Pharmacia International, Capelle aan den Ijssel, The Netherlands) or Bausch & Lomb S112UV lenses (Bausch & Lomb Inc, New York, New York, USA) were implanted. Both lenses are single-piece polymethyl methacrylate (PMMA), open-loop, semi-flexible lens with 4-point fixation. In the secondary scleral-fixated IOL group, Alcon CZ70BD lenses (Alcon Laboratories, Forth Worth, Texas, USA), a single-piece PMMA lens with eyelets, were used for all secondary scleral-fixated IOL implantations in the current study. Statistical analyses were performed using PASW software version 18.0 (SPSS/IBM Inc, Chicago, Illinois, USA). Descriptive statistics in both treatment groups were reported. Snellen BCVA was converted into logarithm of the minimal angle of resolution (logMAR) units for analysis. Visual acuities of hand movement and light perception were arbitrarily assigned the equivalent of 1.7 and 1.8 logMAR units, respectively.4,9,10 Group means were compared with independent t test. Complication rates were evaluated using x2 test or Fisher exact test. A multiple linear regression model with latest BCVA as the dependent variable was constructed. Collinearity diagnostic, using an averaged variance inflation factor of more than 3 as cutoff, was included. A P value of 30 mm Hg Residual lens material Severe uveitis Fibrin Hyphema Vitreous incarceration at wound site Intraocular lens capture Choroidal detachment Retinal detachment Endophthalmitis Number of eyes with early complications Late complications (after 1 mo) Bullous keratopathy Persistent intraocular pressure >21 mm Hg Vitreous prolapse into anterior chamber Persistent uveitis Intraocular lens decentration Pseudophakic cystoid macular edema Retinal detachment Number of eyes with late complications
1 Anterior Chamber IOL
28 ScleralFixated IOL
89
74
P Value
49 (66.6%) 16 (21.6%) .000 6 (6.7%) 9 (12.2%) .222 11 (12.4%) 8 (10.8%) .783 13 (14.6%) 4 (4.5%) 1 (1.1%) 7 (7.9%) 0 (0.0%)
1 (1.4%) 5 (6.8%) 0 (0.0%) 3 (4.1%) 1 (1.4%)
.003 .515 .364 .323 .268
1 (1.1%) 0 (0.0%) 2 (2.2%) 2 (2.7%) 1 (1.1%) 0 (0.0%) 2 (2.2%) 0 (0.0%) 62 (69%) 29 (39.2%)
.364 .841 .364 .194 .000
11 (12.4%) 8 (10.8%) .783 12 (13.5%) 17 (23.0%) .115 3 (3.4%)
4 (5.4%)
.524
1 (1.1%) 1 (1.1%) 3 (3.4%)
4 (5.4%) 3 (4.1%) 2 (2.7%)
.118 .229 .805
1 (1.1%) 0 (0.0%) .360 23 (25.8%) 28 (37.8%) .100
18 ¼ primary; 28 ¼ secondary; IOL ¼ intraocular lens.
(39.7%) in the primary ACIOL group and the secondary scleral-fixated IOL group, respectively (P < .001). The primary ACIOL group had significantly more transient corneal edema (P < .001) and residual lens material (P ¼ .003) compared to the secondary scleral-fixated IOL group. Late (after 1 month) postoperative complications occurred in 23 of 89 eyes (25.8%) and 28 of 74 eyes (37.8%) in the primary ACIOL group and the secondary scleral-fixated IOL group, respectively (P ¼ .100). There were no differences in each of the late postoperative complications between the 2 groups (P < .115). Early and late postoperative complications are shown in Table 2. Among the cases in which patients suffered from persistently elevated intraocular pressure, 1 eye (1/12; 8.3%) following primary ACIOL insertion needed laser cyclophotocoagulation VOL. 159, NO. 2
(P ¼ 1.000), while 2 eyes (2/17; 11.8%) receiving secondary scleral-fixated IOL placement needed trabeculectomy (P ¼ .485). Suture erosion occurred in only 2 eyes (2/74; 2.7%) with scleral-fixated IOL implanted (P ¼ .118). There were no cases of IOL-pupil capture, IOL dislocation, or endophthalmitis associated with stitch erosion encountered in our patients following scleralfixated IOL implantation. Eyes without long-term complications had better latest BCVA than eyes with complications (P < .001 for both groups). There was no difference in the latest postoperative BCVA (P ¼ .883) and latest Snellen BCVA of 20/40 or better (P ¼ .911) between the 2 groups in the eyes with no late complications. The latest postoperative logMAR BCVA in the eyes with no late complications was 0.48 6 0.30 and 0.49 6 0.33 in the primary ACIOL group and the secondary scleral-fixated IOL group, respectively. On the contrary, the primary ACIOL group had worse postoperative BCVA (P ¼ .031) and latest Snellen BCVA of 20/ 40 or better (P ¼ .023) compared to the secondary scleralfixated IOL in the eyes with late complications. The latest postoperative logMAR BCVA in the eyes with late complications was 1.25 6 0.63 and 0.86 6 0.59 in the primary ACIOL group and the secondary scleral-fixated IOL group, respectively. The types of cataract operation planned were known in 144 eyes, including 87 of 88 eyes (97.8%) and 57 of 74 eyes (77.0%) in the primary ACIOL group and the secondary scleral-fixated IOL group, respectively. There were more cataract operations unidentified in the secondary scleralfixated IOL group because those cases were referred to our hospital for secondary IOL insertion from the private sector. A total of 72 eyes (72/87; 82.8%) in the primary ACIOL group and 34 eyes (34/57; 59.6%) in the secondary scleral-fixated IOL group underwent phacoemulsification (P < .001). Extracapsular cataract extraction was planned in 15 eyes (15/87; 17.2%) and 23 eyes (23/57; 40.4%) in the primary ACIOL group and the secondary scleral-fixated IOL group, respectively (P < .001). Indeed, most cases were converted to extracapsular cataract extraction when there was inadequate capsular support during phacoemulsification. A multiple linear regression model was constructed with the latest logMAR BCVA as the dependent variable and IOL group (primary ACIOL group vs secondary scleralfixated IOL group), age of patient, postoperative logMAR BCVA at 1 year, presence of early postoperative complication, presence of late postoperative complication, and type of cataract operation planned as the independent variables. There was no evidence of correlation or interaction among the variables included in the regression model. The presence of late complication was an independent predictor for poorer logMAR BCVA at the last follow-up (P < .001). None of the other independent variables was significantly associated with the latest logMAR BCVA. The regression model summary for latest logMAR BCVA is
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TABLE 3. Primary Anterior Chamber vs Secondary Scleral-Fixated Intraocular Lens Implantation in Complicated Cataract Surgeries: Postoperative Latest Best-Corrected Visual Acuity Linear Regression Model Summary Dependent Variable
Independent Variable
Unstandardized b Coefficients
Postoperative BCVA
18 anterior chamber or 28 scleral-fixated IOL Age of patient Planned operation BCVA at 1 year Early complications Late complications
0.008 0.003 0.128 0.046 0.111 0.556
95% Confidence Intervals
0.188 to 0.171 0.007 to 0.012 0.314 to 0.058 0.131 to 0.222 0.064 to 0.286 0.380 to 0.731
P Value
.927 .567 .176 .610 .211 .000
18 ¼ primary; 28 ¼ secondary; BCVA ¼ best-corrected visual acuity; IOL ¼ intraocular lens.
TABLE 4. Primary Anterior Chamber vs Secondary Scleral-Fixated Intraocular Lens Implantation in Complicated Cataract Surgeries: Postoperative Latest Best-Corrected Visual Acuity Linear Regression Model Summary Excluding Planned Operation Dependent Variable
Independent Variable
Unstandardized b Coefficients
Postoperative BCVA
18 anterior chamber or 28 scleral-fixated IOL Age of patient BCVA at 1 year Early complications Late complications
0.049 0.003 0.079 0.123 0.542
95% Confidence Intervals
0.104 to 0.203 0.005 to 0.011 0.084 to 0.241 0.029 to 0.276 0.387 to 0.697
P Value
.526 .458 .341 .112 .000
18 ¼ primary; 28 ¼ secondary; BCVA ¼ best-corrected visual acuity; IOL ¼ intraocular lens.
shown in Table 3. Similar results were seen when the type of cataract operation planned was excluded because the cataract was actually extracted differently than planned. The regression model summary with the type of cataract operation excluded among other independent variables is shown in Table 4.
DISCUSSION COMPARISON BETWEEN ACIOL AND SCLERAL-FIXATED IOL
implantation in eyes without adequate capsular support during cataract extraction has been investigated extensively in the last 2 decades. An assessment by the American Academy of Ophthalmology concluded that implantation of ACIOL and scleral-fixated IOL had comparable safety and efficacy profiles in the absence of capsular support.3 Several comparative trials on secondary insertion of these 2 IOL modalities demonstrated similar visual outcomes and complication rates at intermediate-term follow-up period.5–8 In Evereklioglu and associates’ series of 124 eyes with secondary placement of an open-loop ACIOL or scleral-fixated IOL, the 3-year postoperative logMAR BCVA was 0.24 following implantation of ACIOL and 0.20 after implantation of scleral-fixated IOL.7 Complications occurred in 34% and 25% of the eyes implanted with ACIOL and scleral-fixated IOL, respectively. Likewise, Donaldson and associates compared 181 eyes that 224
had implantation of ACIOL and scleral-fixated IOL. The final postoperative logMAR BCVA at 1 year was 0.48 after ACIOL implantation and 0.40 after scleral-fixated IOL implantation.8 Complications were encountered in 68% of eyes in their study. In a previous study performed in our hospital, primary ACIOL implantation showed a better visual outcome compared to primary scleral-fixated IOL implantation.4 Seventy-two percent of eyes implanted with ACIOL and 47% implanted with scleral-fixated IOL achieved a postoperative Snellen BCVA of 20/40 or better at 3 years. The postoperative logMAR BCVA was 0.32 and 0.49, respectively. The complication profile did not differ significantly between the 2 techniques. An earlier retrospective analysis carried out in our hospital demonstrated no difference in BCVA and late complication profiles between primary and secondary scleral-fixated IOL implantation.9 The postoperative logMAR BCVA was 0.50 for primary scleral-fixated IOL implantation and 0.36 for secondary scleral-fixated IOL implantation after a mean follow-up of 19 months. In our setting, when there is a loss of posterior capsule integrity during cataract extraction, surgeons often choose between primary ACIOL or secondary scleral-fixated IOL implantation, taking into consideration the ease of implantation in the former and better surgical planning for the latter. To the best of our knowledge, the current study is the only large-scale direct comparative study between these 2 modalities for an extended follow-up period in the literature.
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The BCVA in the first postoperative year was similar between primary ACIOL and secondary scleral-fixated IOL implantation. This is similar to the BCVA observed in studies comparing primary or secondary implantation of ACIOL and scleral-fixated IOL in the literature.4,7,8 The logMAR BCVA in these studies ranged from 0.24 to 0.48 after ACIOL implantation and from 0.20 to 0.49 after scleral-fixated IOL implantation. Although our final visual outcome observed at 5 years after IOL insertion was inferior to these ranges, there was no significant difference between the 2 modalities. This was further supported by the multiple linear regression analysis, which showed that IOL modality did not affect the latest BCVA. The decrease in BCVA was mainly caused by the development of late complications. The latest BCVA was only affected by the presence of late complications in our patients according to the regression analysis. Future long-term prospective studies with standardized follow-up schedules would help further delineate the changes in visual outcome between these 2 modalities over time. There were no differences in the absolute spherical equivalent and astigmatism between the 2 groups, signifying minimal impact on IOL power selection and IOL centration in both IOL types. Similar to the report by Lee and associates comparing primary and secondary scleral-fixated IOL implantation,9 there were more eyes with early postoperative complications after primary ACIOL implantation in our study. The most common early complication was transient corneal edema, followed by retained lens material. Complicated cataract operation undergoing primary IOL implantation may pose greater stress to the corneal endothelium owing to prolonged surgery. Also, intraoperative corneal edema attributable to additional manipulation and prolonged surgery may hamper the surgeon’s view. This could explain the higher number of early complications following primary ACIOL implantation observed in the current study. On the contrary, there was no difference in the late complications between the 2 groups. There was no difference in the incidence of corneal decompensation following primary ACIOL (12.4%) and secondary scleralfixated IOL (10.8%) implantation. These figures were higher than those in the literature mainly because of the longer follow-up duration in the present study.5–8 This finding was important to our locality because Chinese eyes tend to have a shallow anterior chamber,11 which puts the corneal endothelium at higher risk of decompensation following the placement of an ACIOL.12 Similar to previous studies,4,8,13 the most frequent late complication observed was persistently high intraocular pressure, which was defined as >21 mm Hg for 3 months requiring medical or surgical intervention. No intergroup difference was found. In Kwong and associates’ series, persistently raised intraocular pressure was seen in 13% of eyes, with no difference between the 2 IOL types,4 while 41% of cases in Donaldson and associates’ series suffered from elevated intraocular pressure, with no intergroup VOL. 159, NO. 2
difference.8 Suture erosion occurred in only 2 eyes (2.7%) with scleral-fixated IOL implanted, which was similar to a recent study comparing long-term outcome of scleral-fixated IOL over a similar follow-up duration.10 Other studies have reported variable incidence of complications following scleral-fixated IOL implantation.10,14,15 The complication rates observed in our study were not inferior to those reported in the literature. The multiple linear regression model in our study showed that the latest BCVA was affected significantly by the presence of late postoperative complications. Univariate comparison between complicated and uncomplicated cases also supported a better final visual outcome in eyes that did not have late complications. In addition, we observed that eyes with late complications had significantly worse BCVA after primary implantation of an ACIOL compared to the secondary implantation of a scleralfixated IOL. This may be explained by the different patterns of late complications encountered in each group. Although not statistically significant, there were more eyes with bullous keratopathy, cystoid macular edema, and retinal detachment in the primary ACIOL group. On the other hand, more eyes with secondary scleral-fixated IOL suffered from high intraocular pressure, persistent anterior uveitis, and IOL tilting, which affected vision to a lesser extent. Limitations of the current study include its retrospective nature, with different surgeons performing the operations. Moreover, we did not have corneal endothelial cell density measured. Cystoid macular edema was mostly detected clinically and was confirmed with fluorescent angiography in our patients. We may have underestimated the actual number of cases suffering from this complication compared to previous studies that used optical coherence tomography routinely for better detection of macular pathologies.16,17 In our hospital, decision making by the operating surgeon on the implantation of either an ACIOL or a scleralfixated IOL in the absence of adequate capsular support was not standardized. There was significant difference in age between the 2 groups in this study. The choice of IOL during a complicated cataract surgery is sometimes dictated by the age of the patients, and this was also reflected in our study, with a tendency of primary ACIOL being implanted in older patients. The rationale behind this practice was the presumption that complications of ACIOL develop later, presumably well beyond the life expectancy of the patients.8,18 Despite the discrepancy, age by itself did not significantly affect the final visual outcome according to our multivariate analysis. There were also differences in the proportion of cataract operations planned between the 2 groups. However, the actual method of cataract extraction was often different from planned in a complicated cataract operation, depending on the stage when capsular support was disrupted. Therefore, it did not affect the latest BCVA in our multiple linear regression model.
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In conclusion, our study shows that there are no longterm differences in the visual outcomes and complication profiles after primary ACIOL implantation or secondary scleral-fixated IOL implantation in a complicated cataract operation when capsular support is inadequate. Primary ACIOL implantation allows immediate aphakic correction
without prolonging the complicated operation extensively. It is recommended when the expertise for scleral-fixated IOL is not available or when a patient cannot afford a second surgery. On the other hand, secondary scleral-fixated IOL implantation allows better surgical planning in a more controlled situation.
ALL AUTHORS HAVE COMPLETED AND SUBMITTED THE ICMJE FORM FOR DISCLOSURE OF POTENTIAL CONFLICTS OF INTEREST. The authors indicate no financial disclosures or funding support. Contributions of authors: concept and design (T.C.Y.C., J.K.M.L., V.J., E.Y.M.L.); analysis and interpretation (T.C.Y.C., J.K.M.L., V.J., E.Y.M.L.); writing the article (T.C.Y.C.); critical revision of the article (T.C.Y.C., J.K.M.L., V.J., E.Y.M.L.); final approval of the article (T.C.Y.C., J.K.M.L., V.J., E.Y.M.L.); data collection (T.C.Y.C., J.K.M.L., E.Y.M.L.); provision of materials, patients, or resources (T.C.Y.C., J.K.M.L., V.J., E.Y.M.L.); statistical expertise (T.C.Y.C.); literature research (T.C.Y.C., J.K.M.L., V.J., E.Y.M.L.); and administrative, technical, or logistic support (T.C.Y.C., V.J.).
REFERENCES 1. Collins JF, Gaster RN, Krol WF, Colling CL, Kirk GF, Smith TJ. A comparison of anterior chamber and posterior chamber intraocular lenses after vitreous presentation during cataract surgery: the Department of Veterans Affairs Cooperative Cataract Study. Am J Ophthalmol 2003;136(1):1–9. 2. Dick HB, Augustin AJ. Lens implant selection with absence of capsular support. Curr Opin Ophthalmol 2001;12(1):47–57. 3. Wagoner MD, Cox TA, Ariyasu RG, Jacobs DS, Karp CL. Intraocular lens implantation in the absence of capsular support: a report by the American Academy of Ophthalmology. Ophthalmology 2003;110(4):840–859. 4. Kwong YY, Yuen HK, Lam RF, Lee VY, Rao SK, Lam DS. Comparison of outcomes of primary scleral-fixated versus primary anterior chamber intraocular lens implantation in complicated cataract surgeries. Ophthalmology 2007;114(1):80–85. 5. Lyle WA, Jin JC. Secondary intraocular lens implantation: anterior chamber vs posterior chamber lenses. Ophthalmic Surg 1993;24(6):375–381. 6. Bellucci R, Pucci V, Morselli S, Bonomi L. Secondary implantation of angle-supported anterior chamber and scleral-fixated posterior chamber intraocular lenses. J Cataract Refract Surg 1996;22(2):247–252. 7. Evereklioglu C, Er H, Bekir NA, Borazan M, Zorllu F. Comparison of secondary implantation of flexible open-loop anterior chamber and scleral-fixated posterior chamber intraocular lenses. J Cataract Refract Surg 2003;29(2):301–308. 8. Donaldson KE, Gorscak JJ, Budenz DL, Feuer WJ, Benz MS, Forster RK. Anterior chamber and sutured posterior chamber intraocular lenses in eyes with poor capsular support. J Cataract Refract Surgery 2005;31(5):903–909. 9. Lee VY, Yuen HK, Kwok AK. Comparison of outcomes of primary and secondary implantation of scleral fixated posterior chamber intraocular lens. Br J Ophthalmol 2003;87(12): 1459–1462.
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10. Luk AS, Young AL, Cheng LL. Long-term outcome of scleralfixated intraocular lens implantation. Br J Ophthalmol 2013; 97(10):1308–1311. 11. Leung CK, Palmiero PM, Weinreb RN, et al. Comparisons of anterior segment biometry between Chinese and Caucasians using anterior segment optical coherence tomography. Br J Ophthalmol 2010;94(9):1184–1189. 12. Holt DG, Young J, Stagg B, Ambati BK. Anterior chamber intraocular lens, sutured posterior chamber intraocular lens, or glued intraocular lens: where do we stand? Curr Opin Ophthalmol 2012;23(1):62–67. 13. Krause L, Bechrakis NE, Heimann H, Salditt S, Foerster MH. Implantation of scleral fixated sutured posterior chamber lenses: a retrospective analysis of 119 cases. Int Ophthalmol 2009;29(4):207–212. 14. Vote BJ, Tranos P, Bunce C, Charteris DG, Da Cruz L. Longterm outcome of combined pars plana vitrectomy and scleral fixated sutured posterior chamber intraocular lens implantation. Am J Ophthalmol 2006;141(2):308–312. 15. Ganekal S, Venkataratnam S, Dorairaj S, Jhanji V. Comparative evaluation of suture-assisted and fibrin glue-assisted scleral fixated intraocular lens implantation. J Refract Surg 2012;28(4):249–252. 16. Vukicevic M, Gin T, Al-Qureshi S. Prevalene of optical coherence tomography-diagnosed postoperative cystoid macular oedema in patients following uncomplicated phacoemulsification cataract surgery. Clin Experiment Ophthalmol 2012;40(3):282–287. 17. Major JC Jr, Wykoff CC, Mariani AF, Chen E, Croft DE, Brown DM. Comparison of spectral-domain and timedomain optical coherence tomography in the detection of neovascular age-related macular degeneration activity. Retina 2014;34(1):48–54. 18. Por YM, Lavin MJ. Techniques of intraocular lens suspension in the absence of capsular/zonular support. Surv Ophthalmol 2005;50(5):429–462.
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Biosketch Tommy C.Y. Chan is a Resident in Hong Kong Eye Hospital. He is also the Honorary Clinical Tutor of Department of Ophthalmology and Visual Sciences of the Chinese University of Hong Kong.
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Biosketch Dr Emmy Y.M. Li is the Associate Consultant of the Hong Kong Eye Hospital and Honorary Clinical Assistant Professor of the Department of Ophthalmology and Visual Sciences of the Chinese University of Hong Kong. She is also a council member of the Hong Kong Ophthalmological Society and the Hong Kong Federation of Societies for Prevention of Blindness.
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