ARTICLE
Mini-monovision versus multifocal intraocular lens implantation Georgios Labiris, MD, PhD, Athanassios Giarmoukakis, MD, Maria Patsiamanidi, MD, Zois Papadopoulos, MD, Vassilios P. Kozobolis, MD, PhD
PURPOSE: To compare the effect of monovision correction and multifocal intraocular lens (IOL) implantation on patient satisfaction, spectacle dependence, visual acuity, and dysphotopsia in cataract patients. SETTING: University Hospital of Alexandroupolis, Democritus University of Thrace, Alexandroupolis, Greece. DESIGN: Prospective randomized trial. METHODS: Patients with a diagnosis of senile cataract with stage 2 nuclear opalescence were randomly assigned to 2 groups: monovision and multifocal IOL implantation. Uncorrected (UDVA) and corrected (CDVA) distance visual acuity, Visual Function Index-14 (VF-14) scores, and spectacle dependence were assessed prior to surgery and 6 months postoperatively. RESULTS: The monovision group comprised 38 patients and the multifocal IOL implantation group, 37 patients. Both techniques provided excellent refractive outcomes in UDVA and VF-14 scores (all P < .01). No significant intergroup differences were detected in VF-14 scores at the final postoperative examination. The monovision group patients presented significantly more spectacle dependence for near vision but less glare. CONCLUSIONS: Monovision and multifocal IOL implantation provided excellent refractive outcomes for distance vision. Multifocal IOL insertion was associated with less dependence on glasses overall but significantly more dysphotopsia. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned. J Cataract Refract Surg 2014; -:-–- Q 2014 ASCRS and ESCRS
Despite continuous advancements in modern cataract surgery,1–3 correction of the postoperative loss of accommodation remains a challenge. Various approaches to the correction of induced iatrogenic presbyopia exist, including premium intraocular
Submitted: February 13, 2014. Final revision submitted: April 15, 2014. Accepted: April 15, 2014. From the Department of Ophthalmology (Labiris, Patsiamanidi, Kozobolis), University Hospital of Alexandroupolis and the Eye Institute of Thrace (Labiris, Giarmoukakis, Papadopoulos, Kozobolis), Alexandroupolis, Greece. Corresponding author: Georgios Labiris, MD, PhD, Ophthalmology Department, University Hospital of Alexandroupolis, 68100 Dragana, Alexandroupolis, Greece. E-mail: [email protected]. Q 2014 ASCRS and ESCRS Published by Elsevier Inc.
lenses (IOLs), such as accommodating and multifocal, and pseudophakic monovision techniques achieved by monofocal IOL implantation. Regardless of the approach chosen by each surgeon to correct or at least delay the onset of post-cataract extraction presbyopia, the ultimate target remains spectacle independence for near and distance activities without compromising the patients' visual function and visual performance. Multifocal IOLs can be refractive, diffractive, or hybrid diffractive–refractive. Diffractive multifocal IOLs use light diffraction to produce 2 focal points, one for distance vision and one for near vision.4,5 In refractive multifocal IOLs, refractive power changes from the center to the periphery of the IOL, thus producing many focal points.4,5 Recent studies of multifocal IOLs report good results for both near and distance vision in terms of spectacle independence,6–8 but these IOLs are frequently 0886-3350/$ - see front matter http://dx.doi.org/10.1016/j.jcrs.2014.06.015
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associated with a number of visual adverse effects, such as dysphotopsia, visual disturbances at night, halos, and glare, mainly due to changes in pupil diameter, causing visual discomfort and compromising patients' satisfaction.9–11 In pseudophakic monovision, 1 eye (dominant) is usually corrected to emmetropia for distance vision and the other (nondominant) is corrected for near vision. Depending on the technique, target refraction of the nondominant eye ranges from 1.00 to 2.50 diopters (D) of myopia.12,13 Monovision has been widely used in presbyopic refractive surgery candidates,12–15 as well as in association with contact lens fitting,16 providing excellent satisfaction rates. However, little evidence of pseudophakic monovision satisfaction outcomes has been published despite the high tolerability rates.17–21 The primary objective of this study was to assess and compare the clinical outcomes and the satisfaction rates of pseudophakic mini-monovision versus bilateral implantation of refractive multifocal IOLs in a sample of cataract patients. PATIENTS AND METHODS This was a prospective clinic-based randomized trial. The study protocol adhered to the tenets of the Declaration of Helsinki, and written informed consent was obtained from all patients. The institutional review board of the Democritus University of Thrace approved the protocol, and the study was conducted at the University Hospital of Alexandroupolis (UHA) in Greece between January and July 2013. The study was registered with ClinicalTrials.gov (NCT01998698). Patients were recruited from the cataract service of the UHA on a consecutive-if-eligible basis. Eligibility criteria included diagnosis of senile cataract with grade 2 nuclear opalescence according to the Lens Opacities Classification System III grading scale.22 Using a custom computer randomization program, all patients randomly populated 2 study groups according to the cataract extraction technique used: monovision and multifocal IOL. Exclusion criteria included manifest astigmatism more than 1.00 D, reports of headaches and/or eyestrain associated with visual activities, positive pathologic ocular cover test (near and distance), and/or the Mallett disparity test (near and distance) and the double Maddox rod test, endothelial cell count less than 1900 cells/mm2, glaucoma, intraocular pressurelowering medications, former incisional surgery, former diagnosis of corneal disease, former diagnosis of fundus disease, diabetes, autoimmune or mental diseases.
Surgical Technique All surgery was performed by the same surgeon (G.L) using the Alcon Infiniti Vision System platform (80% continuous amplitude with 350 mm Hg vacuum limit and 40 mL/min aspiration flow rate). Pupils were dilated with tropicamide 0.5% (Tropixal) and phenylephrine hydrochloride 5% (Phenylephrine). The periorbital skin and the lids were cleaned, and the conjunctival cul-de-sac was irrigated with povidone–iodine (Betadine). Patients received topical anesthesia with proparacaine hydrochloride
0.5% drops (3 drops prior to surgery). Sodium hyaluronate 1.0% (Provisc) ophthalmic viscosurgical device was injected into the anterior chamber through a 2.75 mm superotemporal or superonasal (11 o’clock) self-sealing clear-corneal incision. A continuous curvilinear capsulorhexis was performed with a forceps and hydrodissection with balanced salt solution. In the monovision group, a foldable hydrophilic acrylic IOL (SN60WF, Alcon Laboratories, Inc.) was inserted in the capsular bags, targeting 0.50 D in the dominant eye and 1.25 D in the nondominant eye. Ocular dominance was assessed using the hole-in-the-card test. In multifocal IOL patients, an aspheric multifocal IOL (Isert PY60MV, Hoya Surgical Optics, Inc.) was implanted in both eyes. It is a preloaded poly(methyl methacrylate) 3-piece 3-zone refractive multifocal IOL with C3.00 D of near addition. The same postoperative regimen was prescribed for all patients. It included a fixed combination of tobramycin 0.3% and dexamethasone 0.1% (Tobradex) 6 times daily, gradually tapered over a month.
Data Collection All preoperative and postoperative assessments were done by the same ophthalmologist, who had no direct involvement in the study. Intraocular lens power calculation was performed with optical biometry (IOLMaster, software version 5.2.1.001, Carl Zeiss Meditec AG). A standardized script was used for dysphotopsia assessment, which was repeated in case of uncertainty. Two direct 4-scale Likert-type questions (always, most of the times, sometimes, never) that pertained to the subjective perception of glare and unwanted shadows were included. Care was taken to ensure that the patient understood the scale before answering the questions. The need for spectacles (ie, spectacle dependence) was evaluated for distance vision and near vision by 2 direct 4-scale Likert-type questions (always, most of the times, sometimes, never). Functional impairment was assessed with the Visual Function Index-14 (VF-14) questionnaire, which is among the most prevalent instruments used with cataract patients. To the total VF-14 score, 2 additional scores were calculated: (1) near vision VF score that was derived from the items that assessed the perceived difficulty in near vision activities (items 1, 2, 3, 7, 8, 9, and 11) and distance vision VF score that derived from the items that assessed the perceived difficulty in distance vision activities (items 4, 5, 6, 10, 12, 13, and 14). All VF-14 scores were obtained 1 day prior to surgery and 6 months after the second-eye operation. The following clinical indexes were evaluated: binocular uncorrected distance visual acuity (binocular UDVA) using the Greek version of the Early Treatment Diabetic Retinopathy Study Chart at 4 meters distance, binocular uncorrected near visual acuity (binocular UNVA), contrast sensitivity using the Pelli-Robson chart, and Titmus stereo acuity at a distance of 40 cm under photopic conditions (85 cd/m2). Monovision patients were provided with an addition of 2.5 D for the stereoacuity test.
Statistical Analysis The normality of measured data were evaluated by the Kolmogorov-Smirnov test. Normal distribution data were assessed by the Student t test. Nonparametric data were assessed with the Mann-Whitney U test; P values less than 0.05 were considered statistically significant. All statistical
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Table 1. Demographic and preoperative data for study participants.
Table 2. Postoperative clinical parameters.
Study Group
No.
Age (Y)
LOCS
CDVA
Parameter
Monovision Group
Multifocal IOL Group
P Value
Monovision Multifocal IOL P value
38 37 NA
59.5 G 10.4 61.3 G 9.3 0.34
Stage 2 Stage 2 NA
0.28 G 0.07 0.31 G 0.11 0.16
SE (dominant) SE (nondominant) bUDVA bUNVA CS Stereopsis Glare Shadows
0.43 G 0.11 1.23 G 0.23 0.95G 0.07 1.87G 0.73 1.39G 0.11 71 (40, 800) 0.06 G 0.24 0.21 G 0.48
0.12 G 0.18 0.21 G 0.22 0.92 G 0.09 1.21 G 0.41 1.40 G 0.17 75 (40, 800) 0.21 G 0.41 0.57 G 0.75
.03 .01 .15 .47 .41 .12 .08 .02
CDVA Z corrected distance visual acuity; LOCS Z Lens Opacities Classification system; NA Z not applicable
analyses were performed with the Medcalc version 9.6.2.0 (Medcalc software).
RESULTS Seventy-five patients (36 men and 39 women; mean age 60.4 years G 9.8 [SD]) were recruited and populated the monovision group (38 patients) and the multifocal IOL group (37 patients). Detailed demographic and preoperative corrected distance visual acuity (CDVA) are presented in Table 1. No significant differences in age (P Z .34) and CDVA (P Z .16) were detected between the groups. Significant postoperative improvement was detected in binocular UDVA in the monovision group (0.28 G 0.07 D preoperatively and 0.95 G 0.07 D postoperatively; P ! .01) and the multifocal IOL group (0.31 G 0.11 D preoperatively and 0.92 G 0.09 D postoperatively; P ! .01). However, no significant differences in postoperative binocular UDVA (P Z .15), binocular UNVA (P Z .47), contrast sensitivity (P Z .41), and stereopsis (P Z .12) were detected between the groups. As expected, significant differences in postoperative spherical equivalent were detected in dominant (P Z .03) and nondominant (P Z .01) eyes. Regarding dysphotopsia, multifocal IOL patients perceived more unwanted shadows (P Z .02) and insignificantly more glare (P Z .08). All postoperative comparisons of clinical indexes are presented in Table 2. Spectacle dependence and VF-14 scores are presented in Table 3. No significant differences in total VF-14 scores (P Z .18) and the VF items that pertained to near (P Z .09) and distance (P Z .08) vision were detected. Regarding spectacles, multifocal IOL patients presented significantly less dependence for near vision (P ! .01); both groups demonstrated almost excellent spectacle independence for distance vision. Twelve patients (31.4%) in the monovision group were spectacle free compared with 26 patients (65.7%) in the multifocal IOL group. DISCUSSION In this study, we attempted to assess and compare the efficacy and satisfaction rates of pseudophakic
bUDVA Z binocular uncorrected distance visual acuity; bUNVA Z binocular uncorrected near visual acuity; CS Z contrast sensitivity; SE Z spherical equivalent
monovision and bilateral multifocal IOL implantation for the correction of postoperative presbyopia. Despite the common application of monovision approaches, primarily in refractive surgery candidates of presbyopic age, the international literature provides limited data regarding success and satisfaction rates of pseudophakic monovision. Previous studies of pseudophakic monovision report variable total spectacle independence rates by targeting the near eye around 1.00 to 2.00 D, while the other eye is adjusted to emmetropia for distance vision.6,20,21,23 In contrast, in our monovision group, the dominant eye was deliberately targeted to 0.50 D instead of emmetropia, while the fellow nondominant eye was set at 1.25 D, a typical target in mini-monovision corrections.6,20 This approach resulted in slightly better outcomes in terms of spectacle independence, with 31.4% of the monovision patients stating they were spectacle free for distance and near activities. Although our results can be compared only indirectly with the results in previous reports, the better outcomes could be attributed to the following reasons: (1) the bilateral myopic defocus of our patients, which acts beneficially for near visual acuity without affecting distance vision; (2) the strict inclusion criteria for the monovision group, which excluded any patient with suspicion for heterophoria intolerance; and (3) the actual mini-monovision correction, which is unlikely to interrupt fusion. Therefore, monovision was well tolerated, while stereopsis and contrast sensitivity were not compromised by the myopic defocus, as previously suggested,24,25 with both being similar to former reports.20,26 In our multifocal group, the refractive IOL was implanted bilaterally, targeting emmetropia in both eyes. In our study, the multifocal IOL provided excellent outcomes in distance and near vision, with
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Table 3. Visual function questionnaire scores.
Parameter
Monovision Group
Multifocal IOL Group
VF14 score 91.61 G 9.17 90.14 G 8.66 VF14 (near vision) 88.97 G 11.25 91.37 G 9.37 VF14 (distance vision) 92.92 G 9.25 89.08 G 10.07 SD (near vision) 0.87 G 0.78 0.36 G 0.60 SD (distance vision) 0.06 G 0.24 0.09 G 0.29 SFP (near vision) 31.40% 72.10% SFP (distance vision) 94.20% 91.40% SFP (total) 31.40% 65.70%
P Value .18 .09 .08 !.01 .64 NA NA NA
SD Z spectacle dependence; SFP Z spectacle-free patients; VF14 Z Visual Function 14
65.7% of the patients declaring they were totally spectacle independent. Spectacle independence was better than corresponding rates reported for other refractive multifocal IOLs27 but inferior to those achieved with diffractive IOLs.21,28,29 The lower independence rates can be attributed to the principal difference between the 2 types of multifocal IOLs (refractive and diffractive); ie, refractive IOLs produce multiple focuses and distribute light depending on pupil size to have better intermediate vision (60 to 80 cm), whereas diffractive IOLs are bifocal, producing 2 focuses, 1 for distance and 1 for near, providing better near vision while being independent of pupil size.30 Moreover, in accordance with literature reports, which suggest that refractive IOLs produce more visual disturbances than diffractive and monofocal IOLs,5,21,30 the multifocal arm of our study experienced more dysphotopsia phenomena than the monofocal arm. Nevertheless, only unwanted shadows were significantly more frequent in the multifocal group; visual function, according to the VF-14 score, was excellent in both groups, showing no compromise of visual ability because of visual disturbances. In conclusion, both methods appear to be viable approaches for the postoperative loss of accommodation following cataract extraction. Both study groups presented excellent outcomes in distance vision and visual function. The multifocal arm presented better near vision and significantly higher spectacle independence rates, whereas the monovision arm reported fewer postoperative visual disturbances with acceptable overall spectacle independence. Our results confirm our clinical impression that when heterophoria intolerance is excluded in the preoperative assessment and the patient's expectations are realistic, mini-monovision is the treatment of choice, especially for patients with tight budgets. When spectacle independence is the primary objective, modern
multifocal IOLs provide the best outcomes with minimal dysphotopic side effects. Studies with larger cohorts are necessary to confirm our results and further evaluate the long-term efficacy of both approaches. WHAT WAS KNOWN Monovision is a prevalent surgical technique in cataract patients. Most pseudophakic monovision studies aim for emmetropia in the dominant eye and a variable rate of myopia in the nondominant one. Bilateral multifocal IOL implantation is a prevalent method for pseudophakic spectacles independence. The literature provides limited comparative data on subjective patient satisfaction. WHAT THIS STUDY ADDS A therapeutic algorithm for mini-monovision with bilateral myopic defocus of variable rate within dominant and nondominant eye is explored. Outcomes suggest high tolerability rates and satisfaction with significant spectacle-free percentages.
REFERENCES 1. Chang JSM, Chen IN, Chan W-M, Ng JCM, Chan VKC, Law AKP. Initial evaluation of a femtosecond laser system in cataract surgery. J Cataract Refract Surg 2014; 40:29–36 2. Labiris G, Gatzioufas Z, Giarmoukakis A, Sideroudi H, Kozobolis VP. Liquefaction versus torsional IP: a comparative study on endothelial cells, corneal edema and corneal sensitivity. Ophthalmic Res 2013; 49:37–42 3. Schuster AK, Tesarz J, Vossmerbaeumer U. The impact on vision of aspheric to spherical monofocal intraocular lenses in cataract surgery; a systematic review with meta-analysis. Ophthalmology 2013; 120:2166–2175 4. Bellucci R. Multifocal intraocular lenses. Curr Opin Ophthalmol 2005; 16:33–37 5. Barisic A, Dekaris I, Gabric N, Bohac M, Romac I, Mravicic I, Lazic R. Comparison of diffractive and refractive multifocal intraocular lenses in presbyopia treatment. Coll Antropol 2008; 32(suppl 2):27–31. Available at: http://hrcak.srce.hr/file/54732. Accessed May 14, 2014 6. Zhang F, Sugar A, Jacobsen G, Collins M. Visual function and spectacle independence after cataract surgery: bilateral diffractive multifocal intraocular lenses versus monovision pseudophakia. J Cataract Refract Surg 2011; 37:853–858 7. Hayashi K, Yoshida M, Hayashi H. All-distance visual acuity and contrast visual acuity in eyes with a refractive multifocal intraocular lens with minimal added power. Ophthalmology 2009; 116:401–408 ndez-Vega L, Puchades C, Monte s-Mico R. 8. Alfonso JF, Ferna Intermediate visual function with different multifocal intraocular lens models. J Cataract Refract Surg 2010; 36:733–739
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9. Shimizu K, Ito M. Dissatisfaction after bilateral multifocal intraocular lens implantation: an electrophysiology study. J Refract Surg 2011; 27:309–312 10. de Vries NE, Webers CAB, Touwslager WRH, Bauer NJC, de Brabander J, Berendschot TT, Nuijts RMMA. Dissatisfaction after implantation of multifocal intraocular lenses. J Cataract Refract Surg 2011; 37:859–865 11. Woodward MA, Randleman JB, Stulting RD. Dissatisfaction after multifocal intraocular lens implantation. J Cataract Refract Surg 2009; 35:992–997 12. Jain S, Arora I, Azar DT. Success of monovision in presbyopes: review of the literature and potential applications to refractive surgery. Surv Ophthalmol 1996; 40:491–499 13. Jain S, Ou R, Azar DT. Monovision outcomes in presbyopic individuals after refractive surgery. Ophthalmology 2001; 108:1430–1433 14. Miranda D, Krueger RR. Monovision laser in situ keratomileusis for pre-presbyopic and presbyopic patients. J Refract Surg 2004; 20:325–328 15. Goldberg DB. Comparison of myopes and hyperopes after laser in situ keratomileusis monovision. J Cataract Refract Surg 2003; 29:1695–1701 16. Johannsdottir KR, Stelmach LB. Monovision: a review of the scientific literature. Optom Vis Sic 2001; 78:646–651. Available at: http://journals.lww.com/optvissci/Fulltext/2001/09000/Mono vision__a_Review_of_the_Scientific_Literature.9.aspx. Accessed May 14, 2014 17. Greenbaum S. Monovision pseudophakia. J Cataract Refract Surg 2002; 28:1439–1443 18. Handa T, Mukuno K, Uozato H, Niida T, Shoji N, Minei R, Nitta M, Shimizu K. Ocular dominance and patient satisfaction after monovision induced by intraocular lens implantation. J Cataract Refract Surg 2004; 30:769–774 19. Ito M, Shimizu K, Amano R, Handa T. Assessment of visual performance in pseudophakic monovision. J Cataract Refract Surg 2009; 35:710–714 20. Finkelman YM, Ng JQ, Barrett GD. Patient satisfaction and visual function after pseudophakic monovision. J Cataract Refract Surg 2009; 35:998–1002 21. Wilkins MR, Allan BD, Rubin GS, Findl O, Hollick EJ, Bunce C, Xing W; for the Moorfields IOL Study Group. Randomized trial of multifocal intraocular lenses versus monovision after
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bilateral cataract surgery. Ophthalmology 2013; 120:2449– 2455.e1 Chylack LT Jr, Wolfe JK, Singer DM, Leske MC, Bullimore MA, Bailey IL, Friend J, McCarthy D, Wu S-Y. for the Longitudinal Study of Cataract Study Group. The Lens Opacities Classification System III. Arch Ophthalmol 1993; 111:831–836. Available at: http://www.chylackinc.com/LOCS_III/LOCS_III_Certification_files/LOCS_III_Reprint_pdf.pdf. Accessed May 14, 2014 Ito M, Shimizu K, Iida Y, Amano R. Five-year clinical study of patients with pseudophakic monovision. J Cataract Refract Surg 2012; 38:1440–1445 Hayashi K, Hayashi H. Stereopsis in bilaterally pseudophakic patients. J Cataract Refract Surg 2004; 30:1466–1470 Wright KW, Guemes A, Kapadia MS, Wilson SE. Binocular function and patient satisfaction after monovision induced by myopic photorefractive keratectomy. J Cataract Refract Surg 1999; 25:177–182 Elgohary MA, Beckingsale AB. Effect of illumination on visual function after monofocal and multifocal intraocular lens implantation. Eye 2006; 20:144–149. Available at: http://www. nature.com/eye/journal/v20/n2/pdf/6701820a.pdf. Accessed May 14, 2014 Harman FE, Maling S, Kampougeris G, Langan L, Khan I, Lee N, Bloom PA. Comparing the 1CU accommodative, multifocal, and monofocal intraocular lenses; a randomized trial. Ophthalmology 2008; 115:993–1001 Maxwell WA, Cionni RJ, Lehmann RP, Modi SS. Functional outcomes after bilateral implantation of apodized diffractive aspheric acrylic intraocular lenses with a C3.0 or C4.0 D addition power; randomized multicenter clinical study. J Cataract Refract Surg 2009; 35:2054–2061 Packer M, Chu YR, Waltz KL, Donnenfeld ED, Wallace RB III, Featherstone K, Smith P, Bentow SS, Tarantino N. Evaluation of the aspheric Tecnis multifocal intraocular lens: one-year results from the first cohort of the Food and Drug Administration clinical trial. Am J Ophthalmol 2010; 149:577–584. Available at: http://download.journals.elsevierhealth.com/pdfs/journals/00029394/PIIS0002939409008101.pdf. Accessed May 14, 2014 Chiam PJT, Chan JH, Haider SI, Karia N, Kasaby H, Aggarwal RK. Functional vision with bilateral ReZoom and ReSTOR intraocular lenses 6 months after cataract surgery. J Cataract Refract Surg 2007; 33:2057–2061
J CATARACT REFRACT SURG - VOL -, - 2014
Mini-monovision versus multifocal intraocular lens implantation Georgios Labiris, MD, PhD, Athanassios Giarmoukakis, MD, Maria Patsiamanidi, MD, Zois Papadopoulos, MD, Vassilios P. Kozobolis, MD, PhD
PURPOSE: To compare the effect of monovision correction and multifocal intraocular lens (IOL) implantation on patient satisfaction, spectacle dependence, visual acuity, and dysphotopsia in cataract patients. SETTING: University Hospital of Alexandroupolis, Democritus University of Thrace, Alexandroupolis, Greece. DESIGN: Prospective randomized trial. METHODS: Patients with a diagnosis of senile cataract with stage 2 nuclear opalescence were randomly assigned to 2 groups: monovision and multifocal IOL implantation. Uncorrected (UDVA) and corrected (CDVA) distance visual acuity, Visual Function Index-14 (VF-14) scores, and spectacle dependence were assessed prior to surgery and 6 months postoperatively. RESULTS: The monovision group comprised 38 patients and the multifocal IOL implantation group, 37 patients. Both techniques provided excellent refractive outcomes in UDVA and VF-14 scores (all P < .01). No significant intergroup differences were detected in VF-14 scores at the final postoperative examination. The monovision group patients presented significantly more spectacle dependence for near vision but less glare. CONCLUSIONS: Monovision and multifocal IOL implantation provided excellent refractive outcomes for distance vision. Multifocal IOL insertion was associated with less dependence on glasses overall but significantly more dysphotopsia. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned. J Cataract Refract Surg 2014; -:-–- Q 2014 ASCRS and ESCRS
Despite continuous advancements in modern cataract surgery,1–3 correction of the postoperative loss of accommodation remains a challenge. Various approaches to the correction of induced iatrogenic presbyopia exist, including premium intraocular
Submitted: February 13, 2014. Final revision submitted: April 15, 2014. Accepted: April 15, 2014. From the Department of Ophthalmology (Labiris, Patsiamanidi, Kozobolis), University Hospital of Alexandroupolis and the Eye Institute of Thrace (Labiris, Giarmoukakis, Papadopoulos, Kozobolis), Alexandroupolis, Greece. Corresponding author: Georgios Labiris, MD, PhD, Ophthalmology Department, University Hospital of Alexandroupolis, 68100 Dragana, Alexandroupolis, Greece. E-mail: [email protected]. Q 2014 ASCRS and ESCRS Published by Elsevier Inc.
lenses (IOLs), such as accommodating and multifocal, and pseudophakic monovision techniques achieved by monofocal IOL implantation. Regardless of the approach chosen by each surgeon to correct or at least delay the onset of post-cataract extraction presbyopia, the ultimate target remains spectacle independence for near and distance activities without compromising the patients' visual function and visual performance. Multifocal IOLs can be refractive, diffractive, or hybrid diffractive–refractive. Diffractive multifocal IOLs use light diffraction to produce 2 focal points, one for distance vision and one for near vision.4,5 In refractive multifocal IOLs, refractive power changes from the center to the periphery of the IOL, thus producing many focal points.4,5 Recent studies of multifocal IOLs report good results for both near and distance vision in terms of spectacle independence,6–8 but these IOLs are frequently 0886-3350/$ - see front matter http://dx.doi.org/10.1016/j.jcrs.2014.06.015
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associated with a number of visual adverse effects, such as dysphotopsia, visual disturbances at night, halos, and glare, mainly due to changes in pupil diameter, causing visual discomfort and compromising patients' satisfaction.9–11 In pseudophakic monovision, 1 eye (dominant) is usually corrected to emmetropia for distance vision and the other (nondominant) is corrected for near vision. Depending on the technique, target refraction of the nondominant eye ranges from 1.00 to 2.50 diopters (D) of myopia.12,13 Monovision has been widely used in presbyopic refractive surgery candidates,12–15 as well as in association with contact lens fitting,16 providing excellent satisfaction rates. However, little evidence of pseudophakic monovision satisfaction outcomes has been published despite the high tolerability rates.17–21 The primary objective of this study was to assess and compare the clinical outcomes and the satisfaction rates of pseudophakic mini-monovision versus bilateral implantation of refractive multifocal IOLs in a sample of cataract patients. PATIENTS AND METHODS This was a prospective clinic-based randomized trial. The study protocol adhered to the tenets of the Declaration of Helsinki, and written informed consent was obtained from all patients. The institutional review board of the Democritus University of Thrace approved the protocol, and the study was conducted at the University Hospital of Alexandroupolis (UHA) in Greece between January and July 2013. The study was registered with ClinicalTrials.gov (NCT01998698). Patients were recruited from the cataract service of the UHA on a consecutive-if-eligible basis. Eligibility criteria included diagnosis of senile cataract with grade 2 nuclear opalescence according to the Lens Opacities Classification System III grading scale.22 Using a custom computer randomization program, all patients randomly populated 2 study groups according to the cataract extraction technique used: monovision and multifocal IOL. Exclusion criteria included manifest astigmatism more than 1.00 D, reports of headaches and/or eyestrain associated with visual activities, positive pathologic ocular cover test (near and distance), and/or the Mallett disparity test (near and distance) and the double Maddox rod test, endothelial cell count less than 1900 cells/mm2, glaucoma, intraocular pressurelowering medications, former incisional surgery, former diagnosis of corneal disease, former diagnosis of fundus disease, diabetes, autoimmune or mental diseases.
Surgical Technique All surgery was performed by the same surgeon (G.L) using the Alcon Infiniti Vision System platform (80% continuous amplitude with 350 mm Hg vacuum limit and 40 mL/min aspiration flow rate). Pupils were dilated with tropicamide 0.5% (Tropixal) and phenylephrine hydrochloride 5% (Phenylephrine). The periorbital skin and the lids were cleaned, and the conjunctival cul-de-sac was irrigated with povidone–iodine (Betadine). Patients received topical anesthesia with proparacaine hydrochloride
0.5% drops (3 drops prior to surgery). Sodium hyaluronate 1.0% (Provisc) ophthalmic viscosurgical device was injected into the anterior chamber through a 2.75 mm superotemporal or superonasal (11 o’clock) self-sealing clear-corneal incision. A continuous curvilinear capsulorhexis was performed with a forceps and hydrodissection with balanced salt solution. In the monovision group, a foldable hydrophilic acrylic IOL (SN60WF, Alcon Laboratories, Inc.) was inserted in the capsular bags, targeting 0.50 D in the dominant eye and 1.25 D in the nondominant eye. Ocular dominance was assessed using the hole-in-the-card test. In multifocal IOL patients, an aspheric multifocal IOL (Isert PY60MV, Hoya Surgical Optics, Inc.) was implanted in both eyes. It is a preloaded poly(methyl methacrylate) 3-piece 3-zone refractive multifocal IOL with C3.00 D of near addition. The same postoperative regimen was prescribed for all patients. It included a fixed combination of tobramycin 0.3% and dexamethasone 0.1% (Tobradex) 6 times daily, gradually tapered over a month.
Data Collection All preoperative and postoperative assessments were done by the same ophthalmologist, who had no direct involvement in the study. Intraocular lens power calculation was performed with optical biometry (IOLMaster, software version 5.2.1.001, Carl Zeiss Meditec AG). A standardized script was used for dysphotopsia assessment, which was repeated in case of uncertainty. Two direct 4-scale Likert-type questions (always, most of the times, sometimes, never) that pertained to the subjective perception of glare and unwanted shadows were included. Care was taken to ensure that the patient understood the scale before answering the questions. The need for spectacles (ie, spectacle dependence) was evaluated for distance vision and near vision by 2 direct 4-scale Likert-type questions (always, most of the times, sometimes, never). Functional impairment was assessed with the Visual Function Index-14 (VF-14) questionnaire, which is among the most prevalent instruments used with cataract patients. To the total VF-14 score, 2 additional scores were calculated: (1) near vision VF score that was derived from the items that assessed the perceived difficulty in near vision activities (items 1, 2, 3, 7, 8, 9, and 11) and distance vision VF score that derived from the items that assessed the perceived difficulty in distance vision activities (items 4, 5, 6, 10, 12, 13, and 14). All VF-14 scores were obtained 1 day prior to surgery and 6 months after the second-eye operation. The following clinical indexes were evaluated: binocular uncorrected distance visual acuity (binocular UDVA) using the Greek version of the Early Treatment Diabetic Retinopathy Study Chart at 4 meters distance, binocular uncorrected near visual acuity (binocular UNVA), contrast sensitivity using the Pelli-Robson chart, and Titmus stereo acuity at a distance of 40 cm under photopic conditions (85 cd/m2). Monovision patients were provided with an addition of 2.5 D for the stereoacuity test.
Statistical Analysis The normality of measured data were evaluated by the Kolmogorov-Smirnov test. Normal distribution data were assessed by the Student t test. Nonparametric data were assessed with the Mann-Whitney U test; P values less than 0.05 were considered statistically significant. All statistical
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Table 1. Demographic and preoperative data for study participants.
Table 2. Postoperative clinical parameters.
Study Group
No.
Age (Y)
LOCS
CDVA
Parameter
Monovision Group
Multifocal IOL Group
P Value
Monovision Multifocal IOL P value
38 37 NA
59.5 G 10.4 61.3 G 9.3 0.34
Stage 2 Stage 2 NA
0.28 G 0.07 0.31 G 0.11 0.16
SE (dominant) SE (nondominant) bUDVA bUNVA CS Stereopsis Glare Shadows
0.43 G 0.11 1.23 G 0.23 0.95G 0.07 1.87G 0.73 1.39G 0.11 71 (40, 800) 0.06 G 0.24 0.21 G 0.48
0.12 G 0.18 0.21 G 0.22 0.92 G 0.09 1.21 G 0.41 1.40 G 0.17 75 (40, 800) 0.21 G 0.41 0.57 G 0.75
.03 .01 .15 .47 .41 .12 .08 .02
CDVA Z corrected distance visual acuity; LOCS Z Lens Opacities Classification system; NA Z not applicable
analyses were performed with the Medcalc version 9.6.2.0 (Medcalc software).
RESULTS Seventy-five patients (36 men and 39 women; mean age 60.4 years G 9.8 [SD]) were recruited and populated the monovision group (38 patients) and the multifocal IOL group (37 patients). Detailed demographic and preoperative corrected distance visual acuity (CDVA) are presented in Table 1. No significant differences in age (P Z .34) and CDVA (P Z .16) were detected between the groups. Significant postoperative improvement was detected in binocular UDVA in the monovision group (0.28 G 0.07 D preoperatively and 0.95 G 0.07 D postoperatively; P ! .01) and the multifocal IOL group (0.31 G 0.11 D preoperatively and 0.92 G 0.09 D postoperatively; P ! .01). However, no significant differences in postoperative binocular UDVA (P Z .15), binocular UNVA (P Z .47), contrast sensitivity (P Z .41), and stereopsis (P Z .12) were detected between the groups. As expected, significant differences in postoperative spherical equivalent were detected in dominant (P Z .03) and nondominant (P Z .01) eyes. Regarding dysphotopsia, multifocal IOL patients perceived more unwanted shadows (P Z .02) and insignificantly more glare (P Z .08). All postoperative comparisons of clinical indexes are presented in Table 2. Spectacle dependence and VF-14 scores are presented in Table 3. No significant differences in total VF-14 scores (P Z .18) and the VF items that pertained to near (P Z .09) and distance (P Z .08) vision were detected. Regarding spectacles, multifocal IOL patients presented significantly less dependence for near vision (P ! .01); both groups demonstrated almost excellent spectacle independence for distance vision. Twelve patients (31.4%) in the monovision group were spectacle free compared with 26 patients (65.7%) in the multifocal IOL group. DISCUSSION In this study, we attempted to assess and compare the efficacy and satisfaction rates of pseudophakic
bUDVA Z binocular uncorrected distance visual acuity; bUNVA Z binocular uncorrected near visual acuity; CS Z contrast sensitivity; SE Z spherical equivalent
monovision and bilateral multifocal IOL implantation for the correction of postoperative presbyopia. Despite the common application of monovision approaches, primarily in refractive surgery candidates of presbyopic age, the international literature provides limited data regarding success and satisfaction rates of pseudophakic monovision. Previous studies of pseudophakic monovision report variable total spectacle independence rates by targeting the near eye around 1.00 to 2.00 D, while the other eye is adjusted to emmetropia for distance vision.6,20,21,23 In contrast, in our monovision group, the dominant eye was deliberately targeted to 0.50 D instead of emmetropia, while the fellow nondominant eye was set at 1.25 D, a typical target in mini-monovision corrections.6,20 This approach resulted in slightly better outcomes in terms of spectacle independence, with 31.4% of the monovision patients stating they were spectacle free for distance and near activities. Although our results can be compared only indirectly with the results in previous reports, the better outcomes could be attributed to the following reasons: (1) the bilateral myopic defocus of our patients, which acts beneficially for near visual acuity without affecting distance vision; (2) the strict inclusion criteria for the monovision group, which excluded any patient with suspicion for heterophoria intolerance; and (3) the actual mini-monovision correction, which is unlikely to interrupt fusion. Therefore, monovision was well tolerated, while stereopsis and contrast sensitivity were not compromised by the myopic defocus, as previously suggested,24,25 with both being similar to former reports.20,26 In our multifocal group, the refractive IOL was implanted bilaterally, targeting emmetropia in both eyes. In our study, the multifocal IOL provided excellent outcomes in distance and near vision, with
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Table 3. Visual function questionnaire scores.
Parameter
Monovision Group
Multifocal IOL Group
VF14 score 91.61 G 9.17 90.14 G 8.66 VF14 (near vision) 88.97 G 11.25 91.37 G 9.37 VF14 (distance vision) 92.92 G 9.25 89.08 G 10.07 SD (near vision) 0.87 G 0.78 0.36 G 0.60 SD (distance vision) 0.06 G 0.24 0.09 G 0.29 SFP (near vision) 31.40% 72.10% SFP (distance vision) 94.20% 91.40% SFP (total) 31.40% 65.70%
P Value .18 .09 .08 !.01 .64 NA NA NA
SD Z spectacle dependence; SFP Z spectacle-free patients; VF14 Z Visual Function 14
65.7% of the patients declaring they were totally spectacle independent. Spectacle independence was better than corresponding rates reported for other refractive multifocal IOLs27 but inferior to those achieved with diffractive IOLs.21,28,29 The lower independence rates can be attributed to the principal difference between the 2 types of multifocal IOLs (refractive and diffractive); ie, refractive IOLs produce multiple focuses and distribute light depending on pupil size to have better intermediate vision (60 to 80 cm), whereas diffractive IOLs are bifocal, producing 2 focuses, 1 for distance and 1 for near, providing better near vision while being independent of pupil size.30 Moreover, in accordance with literature reports, which suggest that refractive IOLs produce more visual disturbances than diffractive and monofocal IOLs,5,21,30 the multifocal arm of our study experienced more dysphotopsia phenomena than the monofocal arm. Nevertheless, only unwanted shadows were significantly more frequent in the multifocal group; visual function, according to the VF-14 score, was excellent in both groups, showing no compromise of visual ability because of visual disturbances. In conclusion, both methods appear to be viable approaches for the postoperative loss of accommodation following cataract extraction. Both study groups presented excellent outcomes in distance vision and visual function. The multifocal arm presented better near vision and significantly higher spectacle independence rates, whereas the monovision arm reported fewer postoperative visual disturbances with acceptable overall spectacle independence. Our results confirm our clinical impression that when heterophoria intolerance is excluded in the preoperative assessment and the patient's expectations are realistic, mini-monovision is the treatment of choice, especially for patients with tight budgets. When spectacle independence is the primary objective, modern
multifocal IOLs provide the best outcomes with minimal dysphotopic side effects. Studies with larger cohorts are necessary to confirm our results and further evaluate the long-term efficacy of both approaches. WHAT WAS KNOWN Monovision is a prevalent surgical technique in cataract patients. Most pseudophakic monovision studies aim for emmetropia in the dominant eye and a variable rate of myopia in the nondominant one. Bilateral multifocal IOL implantation is a prevalent method for pseudophakic spectacles independence. The literature provides limited comparative data on subjective patient satisfaction. WHAT THIS STUDY ADDS A therapeutic algorithm for mini-monovision with bilateral myopic defocus of variable rate within dominant and nondominant eye is explored. Outcomes suggest high tolerability rates and satisfaction with significant spectacle-free percentages.
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