Scleral Buckling Surgery for Stage 4B Retinopathy of Prematurity Stuart W. Noorily, MD, Kent Small, MD, Eugene de Juan, Jr., MD, Robert Machemer, MD
R
esults of scleral buckling in 15 consecutive eyes of 13 infants with stage 48 retinopathy of prematurity (ROP) were reviewed. Ten of 15 retinas achieved macular reattachment with a single scleral buckling procedure. Four of 15 retinas unable to be attached by scleral buckling were reattached after the addition of a single vitreous operation. One of 15 retinas was unable to be reattached despite both a scleral buckling and a single vitreous procedure. Despite macular attachment in all except one eye, visual results were disappointing. Fix and follow visual acuity was present in 3 eyes, light perception in 11 eyes, and no light perception in 1 eye. Average follow-up was 10 months. Possible causes for poor visual outcomes despite retinal reattachment include retinal abnormalities as a result of detachment and amblyopia. Ophthalmology 1992; 99:263-268
The optimum timing and modality of surgical intervention for advanced stages of retinopathy of prematurity (ROP) is unclear. Both the anatomic and visual results of late intervention have been disappointing despite vitreous surgery. 1,2 The utility of scleral buckling for less advanced stages ofROP has been suggested in several series. 3- 6 Recently, Greven and Tasman7 reported on the use of scleral buckling in 22 eyes with stages 4 and 5 ROP. Encouraging anatomic and visual results were achieved in their limited number of stage 4B cases. We present a review of our cases of stage 4B ROP treated with primary scleral buckling.
Originally received: May 6, 1991, Revision accepted: August 26, 1991, From the Department of Ophthalmology, Duke University Eye Center, Durham, Presented as a poster at the American Academy of Ophthalmology Annual Meeting, New Orleans, Oct/Nov 1989, Supported by Research to Prevent Blindness, Inc, New York, New York, and the Helena Rubinstein Foundation, New York, New York. The author has no proprietary interest in the development or marketing of any instruments or drugs referred to in this article, Correspondence to Eugene de Juan, Jr., MD, Duke Eye Center, Box 3802, Durham NC 27710.
Materials and Methods Fifteen eyes of 13 infants underwent primary scleral buckling for stage 4B ROP between November 1986 and August 1990 at the Duke University Eye Center. Stage 4B represents a peripheral retinal detachment, which includes foveal detachment in accordance with the expanded international classification of ROP. 8 All patients had clinical assessment that included ocular and medical history, visual acuity, tonometry, indirect ophthalmoscopy, and ultrasonography.9 Preoperative data are summarized in Table 1. Average gestational age at birth was 27.8 weeks (range, 24,5 to 30 weeks). Average birth weight was 1007 g (range, 650 to 1604 g). Average age at surgery was 4.3 months (range, 3 to 7 months). There were 10 boys and 3 girls. Eight eyes were able to perceive light; five had a questionable response to light; and two responses were unrecordable. Of the fellow eyes, 3 had stage 5 ROP, 8 had stage 4,3 had stage 3, and 1 was normal. All except one fellow eye were able to follow or perceive light preoperatively. Preoperative cryotherapy had been performed on 7 eyes (cases 4, 7,8,9, 10, 13, and 14). Plus disease was present at the time of surgery in three eyes (cases 1, 11, and 12). At the time of surgery, all children underwent further examination under general anesthesia, including corneal
263
N
~
5
NA
25
982
8
5
655
7
3
?LP
?LP
26
900
6
4A
LP
26
29
1364
5
Follows large objects
Visual Acuity in Fellow Eye
?LP
LP
LP
Fix/follow
LP
Normal LP Follows 4 light
3
4B
30
1100
4
LP NA
?LP
LP
29 24.5
1604 650
29
2 3
1500
Stage Birth Gestational of Case Weight Age at Visual Fellow Birth (wks) Acuity Eye No. (g)
10/20/88
11/22/88
+
6/23/88
12/10/87
9/25/87
3/13/87 12/10/87
10/24/86
+
+
+
Date of Preoperative Plus Cryotherapy Disease SB
4
7
6
5
6
3
31fz
4
+
Cataract extraction 6 mos after surgery
Vitrectomy/ lentectomy 2 mos after surgery Vitrectomy/ lentectomy for partial TRD5 mos after surgery
Age at Surgery Subretinal (mos) Drainage Reoperation?
9
15
13
6
12
5 28
15
Fully attached
Attached posterior to buckle except for a narrow fold temporally Nasal detachment; macula attached
Fully attached
Attached everywhere except anterior to buckle in temporal periphery Fully attached Possible attachment posteriorly; periphery detached Fully attached
Follow.up Anatomical Description (mos)
Table 1. Preoperative Data and Postoperative Results of Scleral Buckling For Stage 4B ROP
Follows well
LP
LPwith temporal projection ?LP
?NLP
Fixes/follows; grabs large objects; face recognition at 3 meters LP LP
Visual Acuity
?LP
LP
?LP
LP
?NLP
LP ?LP
Imm bead
Fellow Eye
in
Visual Acuity
N
~
760
882
882
915
765
1005
10
11
12
13
14
15
28
28
26
35
35
26
26
LP
LP
LP
LP
LP
LP
LP
5
3
4A
4B
4B
4B
4B
LP
LP
LP
?LP
?LP
LP
LP
+
+
+
+
+
+
08/24/90
05/31/90
OS/24/90
01/05/90
01/05/90
12/18/89
12/01/89
5
3
4
3
3
41h
4
+
Vitrectomy/ lentectomy for anterior funnel detachment 3 mos after surgery
Vitrectomy/ lentectomy for closed funnel detachment 5 mos after surgery
Vitrectomy/ lentectomy for ant funnel detachment 2 mos after surgery
6
6
11
6
6
6
6
Attached posteriorly except for a marked superonasa! tractional fold Attached posteriorly with some persistent temporal traction
Fully attached; optic nerve pale; vessels attenuated Fully attached; optic nerve pale; vessels attenuated Remains detached as open funnel
Attached posteriorly
Fully attached
Fix/ follow
LP
LP
LP
Fix/follow with ?NLP +35.00 CL
LP
LP
LP
LP
LP with 4 cm 4cm OKNwith OKN +6.00 +2.00 X 180 LP with4cm 4cm OKNwith OKN +23.00CL
SB = scleral buckle; ? = questionable; LP = light perception; NA = not available; TRO = traction retinal detachment; NLP = no light perception; OKN = opticokinetic nystagmus; CL = contact lens.
960
9
Ophthalmology
Volume 99, Number 2, February 1992
diameter measurement, slit-lamp biomicroscopy, indirect ophthalmoscopy with scleral depression, ultrasonography, and fundus photography. Surgery was performed by two of the aut~ors (EDJ, RM). All children underwent general anestheSia. All eyes underwent similar surgery with placement of a 2 to 2.5 mm wide 360 0 circumferential silicone band on episclera. The band was secured with a 6-0 nylon scleral fixation suture in each quadrant. The ends of the band were brought together in a Watzke sleeve and ti~tened. Anterior chamber paracentesis was performed In 11 eyes to facilitate tightening of the band. Two eyes underwent drainage of subretinal fluid. Intraoperative cryotherapy was performed transsclerally in 6 eyes in which preoperative cryotherapy was absent or inadequate (cases 1, 2, 3, 6, 11, and 12). No intraoperative or pe~operati:e c?mplications were encountered. No systemIC comphcatIons were noted relating to anesthesia. Anatomic success was defined as macular attachment (Le., full attachment of retina between the temporal vascular arcades). Average follow-up was 10 months (range, 5 to 28 months).
Results Surgical results are presented in Table 1. Scleral buckling alone was successful in reattaching 10 of 15 maculas. Typically macular reattachment occurred early in the first few week~ after surgery, followed by a slow flattening of peripheral retina over the course of 3 to 5 months. Five eyes (cases 3, 4,5, 10, and 13) did not experience macular attachment and therefore underwent additional surgery consisting of a single vitrectomy and lentectomy ~er formed 2 to 5 months after the initial scleral buckhng procedure. Macular reattachment was achieved in all but one of these cases (case 13). Macular attachment appeared to be a stable configuration once achieved. In our series, no detachment progressed after macular reattachment despite the presence of peripheral detachments in 7 eyes followed for an average of 12 months. Visual outcomes in eyes with macular attachment did not differ from fully attached eyes. The postoperative course of 1 child successfully reattached with scleral buckling alone (case 7) was complicated by lens opacification with pupillary block for which she required cataract extraction 6 months postoperatively. Encircling bands did not require removal or revision in any of the 15 eyes throughout the observation period. Figures 1 and 2 demonstrate typical preoperative and postoperative ultrasonographic and photographic findings in successes. Visual acuity in the 10 eyes undergoing scleral buckling alone was fix and follow in 2 eyes and light perception in 8 eyes. Visual acuity in the 5 eyes requiring vitreous surgery was fix and follow in 1 eye, light perception in 3 eyes, and no light perception in 1 eye.
Discussion Recent advances in neonatal medicine have dramatically increased the survival of infants with birth weights less
266
Figure 1. Preoperative (top) and 12 month postoperative (bottom) ultrasounds of case 2. Arrow indicates retinal detachment.
than 1250 g. An estimated 60% to 80% of such infants will develop ROP in the first 1 to 2 months oflife. lO ,11 Of this group, the majority will experience regre~si~n of retinopathy. However, 7.5% will progress to sIgmficant 3 plus disease. 12 Although the implementat~on of cryotherapy halves the risk of retinal detachment In these Infants, . therapy. 12 one fifth still progress beyond stage 3 despIte The mechanism of retinal detachment in ROP is a tractional event that occurs as maturing mesenchymal cells contract just anterior to the fibrovascular shunt. 13 These tractional forces can be relaxed by scleral buckling surgery when the buckle is placed on or posteri?r to the shunt. A significant advantage of scleral buckhng over vitrectomy is in maintaining phakia. Lentectomy is usually required during vitrectomy in these infants due to the retrolental location of proliferation. The timing of surgical intervention in ROP is an important yet unresolved issue. The prognosis for macular reattachment after vitreous surgery has been shown to be much poorer for stage 5 eyes compared with stage 4 eyes. 1,2 In two previous studies, we reported that 33% to 40% of stage 5 eyes compared with 64% to 83% of stage 4 eyes maintain macular attachment. I ,2 In the larger of these studies, 38% of stage 4B eyes achieved visual.acuities of fixation and following or greater compared WIth 11 % of stage 5 eyes? The success of scleral buckling for stage 4 ROP is well documented. McPherson et al 4 reported success in 19 of
Noorily et al . Scleral Buckling Surgery for Stage 4B ROP
Figure 2. Left, preoperative and, right, 34-month postoperative fundus photographs of case 7.
21 cases, Tasman et al 6 in 5 of 6 cases, and Topilow et al 5 in 4 of5 cases. Unfortunately, distinction between 4A, 4B, and 5 detachments was often not made in these reports. Given the occurrence of spontaneous reattachment, particularly in stage 4A eyes,4.10 interpretation of the success of surgical intervention is difficult. Recently, Greven and Tasman,? using the new classification, reported the results of scleral buckling in 3 stage 4B and 18 stage 5 eyes. The rate of reattachment was 100% in stage 4B and 48% in stage 5 eyes. Moreover, visual outcome greater than 20/400 was 66% in stage 4B eyes compared with II % in stage 5 eyes. In our series of IS eyes, 67% (10 of IS) were reattached with a single scleral buckling procedure. However, of these cases, only 2 of 10 (20%) were able to achieve fix and follow acuities. If one includes visual results in 4 eyes ultimately attached with vitreous surgery, still only 3 of 14 (21 %) anatomic successes in our series could fix and follow. Thus, despite the encouraging rate of anatomic success in this and other series, visual results remain disappointing even when one considers the difficulty of obtaining and interpreting visual acuity in these infants. 14.15 The reason these infants often fail to recover significant visual function despite retinal reattachment is unclear. Possible explanations include anatomic retinal abnormalities secondary to detachment and amblyopia. A retinal cause for the poor visual outcome of our infants is compelling. Clinical observations on macular development in premature infants indicate that morphologic maturity may not be present until 42 weeks of gestation. 16 Macular detachment would thus have preceded full macular development in all of our cases. The influence of detachment of an immature macula on its subsequent development is not known. Does amblyopia have a role in the visual loss of these infants? Visual deprivation experiments of von Noorden l7 and Wiesel and Hubel 18 have shown in monkeys and cats that complete occlusion for periods as brief as 2 to 4 weeks results in irreversible amblyopia when performed at less than 12 weeks of age. In these experiments, bilateral deprivation resulted in still greater irreversible anatomic abnormality along the geniculocortical pathway.19 Subsequent studies have implicated form deprivation rather
than light deprivation as the causative factor in occlusion amblyopia. Retinal detachment is clearly capable ofform deprivation and may thus exert an amblyogenic influence in ROP. The series of bilateral congenital cataracts by Rogers et al 20 demonstrated that cataract removal results in uniformly poor vision with pendular nystagmus when performed later than 10 weeks of age. The retinal detachments in our series may be subject to similar constraints. Although most of our detachments occurred between 12 and 20 weeks of age from birth, mean gestational age was only 31.5 weeks, thus within the critical period for deprivation amblyopia. No experimental data currently exist that delineates the critical period for sensory deprivation and its reversibility in premature infants. Similar concerns need to be addressed regarding duration of uncorrected refractive error postoperatively. Creation of high axial myopia with scleral buckling procedures can produce amblyopic risks similar to aphakia. The benefit of vigilant monitoring of refractive error with prompt optical correction is unknown, although this benefit is currently under investigation. Presently, no published data distinguish between retinal and preoperative or postoperative amblyopic causes for poor visual outcomes in the advanced stages ofROP. The difficulties of effectively treating the late stages of this disease will likely continue to challenge both our knowledge and surgical techniques as we aspire to intervene within a complex process of ocular and visual development.
References I. Chong LP, Machemer R, de Juan E. Vitrectomy for advanced stages of retinopathy of prematurity. Am J Ophthalmol 1986; 102:710-16. 2. Zilis JD, de Juan E, Machemer R. Advanced retinopathy of prematurity. The anatomic and visual results of vitreous surgery. Ophthalmology 1990; 97:821-6. 3. McPherson A, Hittner HM. Scleral buckling in 21/2- to 11month old premature infants with retinal detachment associated with acute retrolental fibroplasia. Ophthalmology 1979; 86:819-36.
267
Ophthalmology
Volume 99, Number 2, February 1992
4. McPherson AR, Hittner HM, Lemos R. Retinal detachment in young premature infants with acute retrolental fibroplasia. Thirty-two new cases Ophthalmology 1982; 89:1160-9. 5. Topilow HW, Ackerman AL, Wang FM. The treatment of advanced retinopathy of prematurity by cryotherapy and scleral buckling surgery. Ophthalmology 1985; 92:379-87. 6. Tasman W, Brown GC, Schaffer DB, et al. Cryotherapy for active retinopathy of prematurity. Ophthalmology 1986; 93: 580-5. 7. Greven C, Tasman W. Scleral buckling in stages 4B and 5 retinopathy of prematurity. Ophthalmology 1990; 97:81720. 8. The Committee for the Classification of Retinopathy of Prematurity. An international classification of retinopathy of prematurity. Arch Ophthalmology 1984; 102: 1130-4. 9. de Juan E Jr, Shields S, Machemer R. The results of ultrasound in the management of retinopathy of prematurity. Ophthalmology 1988; 95:884-8. 10. Flynn JT, Bancalari E, Bachynski BN, et al. Retinopathy of prematurity: diagnosis, severity, and natural history. Ophthalmology 1987; 94:620-9. 11. Flynn JT. An international classification of retinopathy of prematurity. Clinical experience. Ophthalmology 1985; 92: 987-94. 12. Cryotherapy for Retinopathy of Prematurity Cooperative Group. Multicenter trial of cryotherapy for retinopathy of
268
13. 14. 15. 16. 17. 18. 19. 20.
prematurity. Preliminary results. Arch Ophthalmol 1988; 106:471-9. Machemer R. Description and pathogenesis of late stages of retinopathy of prematurity. Ophthalmology 1985; 92: 1000-4. Kalina RE. Treatment of retinal detachment due to retinopathy of prematurity: documented disappointment [editorial]. Ophthalmology 1991; 98:3-4. Quinn GE, Dobson V, Barr CC, et al. Visual acuity in infants after vitrectomy for severe retinopathy of prematurity. Ophthalmology 1991; 98:5-13. Isenberg SJ. Macular development in the premature infant. Am J Ophthalmol 1986; 101:74-80. von Noorden GK. Experimental amblyopia in monkeys. Further behavioral observations and clinical correlations. Invest Ophthalmol 1973; 12:721-6. Wiesel TN, Hubel DH. Extent of recovery from the effects of visual deprivation in kittens. J Neurophysiol 1965; 28: 1060-72. von Noorden GK, Crawford MD. Form deprivation without light deprivation produces the visual deprivation syndrome in Macaca mulatta. Brain Res 1977; 129:37-44. Rogers GL, Tishler CL, Tsou BH, et al. Visual acuities in infants with congenital cataracts operated on prior to 6 months of age. Arch Ophthalmol 1981; 99:999-1003.
R
esults of scleral buckling in 15 consecutive eyes of 13 infants with stage 48 retinopathy of prematurity (ROP) were reviewed. Ten of 15 retinas achieved macular reattachment with a single scleral buckling procedure. Four of 15 retinas unable to be attached by scleral buckling were reattached after the addition of a single vitreous operation. One of 15 retinas was unable to be reattached despite both a scleral buckling and a single vitreous procedure. Despite macular attachment in all except one eye, visual results were disappointing. Fix and follow visual acuity was present in 3 eyes, light perception in 11 eyes, and no light perception in 1 eye. Average follow-up was 10 months. Possible causes for poor visual outcomes despite retinal reattachment include retinal abnormalities as a result of detachment and amblyopia. Ophthalmology 1992; 99:263-268
The optimum timing and modality of surgical intervention for advanced stages of retinopathy of prematurity (ROP) is unclear. Both the anatomic and visual results of late intervention have been disappointing despite vitreous surgery. 1,2 The utility of scleral buckling for less advanced stages ofROP has been suggested in several series. 3- 6 Recently, Greven and Tasman7 reported on the use of scleral buckling in 22 eyes with stages 4 and 5 ROP. Encouraging anatomic and visual results were achieved in their limited number of stage 4B cases. We present a review of our cases of stage 4B ROP treated with primary scleral buckling.
Originally received: May 6, 1991, Revision accepted: August 26, 1991, From the Department of Ophthalmology, Duke University Eye Center, Durham, Presented as a poster at the American Academy of Ophthalmology Annual Meeting, New Orleans, Oct/Nov 1989, Supported by Research to Prevent Blindness, Inc, New York, New York, and the Helena Rubinstein Foundation, New York, New York. The author has no proprietary interest in the development or marketing of any instruments or drugs referred to in this article, Correspondence to Eugene de Juan, Jr., MD, Duke Eye Center, Box 3802, Durham NC 27710.
Materials and Methods Fifteen eyes of 13 infants underwent primary scleral buckling for stage 4B ROP between November 1986 and August 1990 at the Duke University Eye Center. Stage 4B represents a peripheral retinal detachment, which includes foveal detachment in accordance with the expanded international classification of ROP. 8 All patients had clinical assessment that included ocular and medical history, visual acuity, tonometry, indirect ophthalmoscopy, and ultrasonography.9 Preoperative data are summarized in Table 1. Average gestational age at birth was 27.8 weeks (range, 24,5 to 30 weeks). Average birth weight was 1007 g (range, 650 to 1604 g). Average age at surgery was 4.3 months (range, 3 to 7 months). There were 10 boys and 3 girls. Eight eyes were able to perceive light; five had a questionable response to light; and two responses were unrecordable. Of the fellow eyes, 3 had stage 5 ROP, 8 had stage 4,3 had stage 3, and 1 was normal. All except one fellow eye were able to follow or perceive light preoperatively. Preoperative cryotherapy had been performed on 7 eyes (cases 4, 7,8,9, 10, 13, and 14). Plus disease was present at the time of surgery in three eyes (cases 1, 11, and 12). At the time of surgery, all children underwent further examination under general anesthesia, including corneal
263
N
~
5
NA
25
982
8
5
655
7
3
?LP
?LP
26
900
6
4A
LP
26
29
1364
5
Follows large objects
Visual Acuity in Fellow Eye
?LP
LP
LP
Fix/follow
LP
Normal LP Follows 4 light
3
4B
30
1100
4
LP NA
?LP
LP
29 24.5
1604 650
29
2 3
1500
Stage Birth Gestational of Case Weight Age at Visual Fellow Birth (wks) Acuity Eye No. (g)
10/20/88
11/22/88
+
6/23/88
12/10/87
9/25/87
3/13/87 12/10/87
10/24/86
+
+
+
Date of Preoperative Plus Cryotherapy Disease SB
4
7
6
5
6
3
31fz
4
+
Cataract extraction 6 mos after surgery
Vitrectomy/ lentectomy 2 mos after surgery Vitrectomy/ lentectomy for partial TRD5 mos after surgery
Age at Surgery Subretinal (mos) Drainage Reoperation?
9
15
13
6
12
5 28
15
Fully attached
Attached posterior to buckle except for a narrow fold temporally Nasal detachment; macula attached
Fully attached
Attached everywhere except anterior to buckle in temporal periphery Fully attached Possible attachment posteriorly; periphery detached Fully attached
Follow.up Anatomical Description (mos)
Table 1. Preoperative Data and Postoperative Results of Scleral Buckling For Stage 4B ROP
Follows well
LP
LPwith temporal projection ?LP
?NLP
Fixes/follows; grabs large objects; face recognition at 3 meters LP LP
Visual Acuity
?LP
LP
?LP
LP
?NLP
LP ?LP
Imm bead
Fellow Eye
in
Visual Acuity
N
~
760
882
882
915
765
1005
10
11
12
13
14
15
28
28
26
35
35
26
26
LP
LP
LP
LP
LP
LP
LP
5
3
4A
4B
4B
4B
4B
LP
LP
LP
?LP
?LP
LP
LP
+
+
+
+
+
+
08/24/90
05/31/90
OS/24/90
01/05/90
01/05/90
12/18/89
12/01/89
5
3
4
3
3
41h
4
+
Vitrectomy/ lentectomy for anterior funnel detachment 3 mos after surgery
Vitrectomy/ lentectomy for closed funnel detachment 5 mos after surgery
Vitrectomy/ lentectomy for ant funnel detachment 2 mos after surgery
6
6
11
6
6
6
6
Attached posteriorly except for a marked superonasa! tractional fold Attached posteriorly with some persistent temporal traction
Fully attached; optic nerve pale; vessels attenuated Fully attached; optic nerve pale; vessels attenuated Remains detached as open funnel
Attached posteriorly
Fully attached
Fix/ follow
LP
LP
LP
Fix/follow with ?NLP +35.00 CL
LP
LP
LP
LP
LP with 4 cm 4cm OKNwith OKN +6.00 +2.00 X 180 LP with4cm 4cm OKNwith OKN +23.00CL
SB = scleral buckle; ? = questionable; LP = light perception; NA = not available; TRO = traction retinal detachment; NLP = no light perception; OKN = opticokinetic nystagmus; CL = contact lens.
960
9
Ophthalmology
Volume 99, Number 2, February 1992
diameter measurement, slit-lamp biomicroscopy, indirect ophthalmoscopy with scleral depression, ultrasonography, and fundus photography. Surgery was performed by two of the aut~ors (EDJ, RM). All children underwent general anestheSia. All eyes underwent similar surgery with placement of a 2 to 2.5 mm wide 360 0 circumferential silicone band on episclera. The band was secured with a 6-0 nylon scleral fixation suture in each quadrant. The ends of the band were brought together in a Watzke sleeve and ti~tened. Anterior chamber paracentesis was performed In 11 eyes to facilitate tightening of the band. Two eyes underwent drainage of subretinal fluid. Intraoperative cryotherapy was performed transsclerally in 6 eyes in which preoperative cryotherapy was absent or inadequate (cases 1, 2, 3, 6, 11, and 12). No intraoperative or pe~operati:e c?mplications were encountered. No systemIC comphcatIons were noted relating to anesthesia. Anatomic success was defined as macular attachment (Le., full attachment of retina between the temporal vascular arcades). Average follow-up was 10 months (range, 5 to 28 months).
Results Surgical results are presented in Table 1. Scleral buckling alone was successful in reattaching 10 of 15 maculas. Typically macular reattachment occurred early in the first few week~ after surgery, followed by a slow flattening of peripheral retina over the course of 3 to 5 months. Five eyes (cases 3, 4,5, 10, and 13) did not experience macular attachment and therefore underwent additional surgery consisting of a single vitrectomy and lentectomy ~er formed 2 to 5 months after the initial scleral buckhng procedure. Macular reattachment was achieved in all but one of these cases (case 13). Macular attachment appeared to be a stable configuration once achieved. In our series, no detachment progressed after macular reattachment despite the presence of peripheral detachments in 7 eyes followed for an average of 12 months. Visual outcomes in eyes with macular attachment did not differ from fully attached eyes. The postoperative course of 1 child successfully reattached with scleral buckling alone (case 7) was complicated by lens opacification with pupillary block for which she required cataract extraction 6 months postoperatively. Encircling bands did not require removal or revision in any of the 15 eyes throughout the observation period. Figures 1 and 2 demonstrate typical preoperative and postoperative ultrasonographic and photographic findings in successes. Visual acuity in the 10 eyes undergoing scleral buckling alone was fix and follow in 2 eyes and light perception in 8 eyes. Visual acuity in the 5 eyes requiring vitreous surgery was fix and follow in 1 eye, light perception in 3 eyes, and no light perception in 1 eye.
Discussion Recent advances in neonatal medicine have dramatically increased the survival of infants with birth weights less
266
Figure 1. Preoperative (top) and 12 month postoperative (bottom) ultrasounds of case 2. Arrow indicates retinal detachment.
than 1250 g. An estimated 60% to 80% of such infants will develop ROP in the first 1 to 2 months oflife. lO ,11 Of this group, the majority will experience regre~si~n of retinopathy. However, 7.5% will progress to sIgmficant 3 plus disease. 12 Although the implementat~on of cryotherapy halves the risk of retinal detachment In these Infants, . therapy. 12 one fifth still progress beyond stage 3 despIte The mechanism of retinal detachment in ROP is a tractional event that occurs as maturing mesenchymal cells contract just anterior to the fibrovascular shunt. 13 These tractional forces can be relaxed by scleral buckling surgery when the buckle is placed on or posteri?r to the shunt. A significant advantage of scleral buckhng over vitrectomy is in maintaining phakia. Lentectomy is usually required during vitrectomy in these infants due to the retrolental location of proliferation. The timing of surgical intervention in ROP is an important yet unresolved issue. The prognosis for macular reattachment after vitreous surgery has been shown to be much poorer for stage 5 eyes compared with stage 4 eyes. 1,2 In two previous studies, we reported that 33% to 40% of stage 5 eyes compared with 64% to 83% of stage 4 eyes maintain macular attachment. I ,2 In the larger of these studies, 38% of stage 4B eyes achieved visual.acuities of fixation and following or greater compared WIth 11 % of stage 5 eyes? The success of scleral buckling for stage 4 ROP is well documented. McPherson et al 4 reported success in 19 of
Noorily et al . Scleral Buckling Surgery for Stage 4B ROP
Figure 2. Left, preoperative and, right, 34-month postoperative fundus photographs of case 7.
21 cases, Tasman et al 6 in 5 of 6 cases, and Topilow et al 5 in 4 of5 cases. Unfortunately, distinction between 4A, 4B, and 5 detachments was often not made in these reports. Given the occurrence of spontaneous reattachment, particularly in stage 4A eyes,4.10 interpretation of the success of surgical intervention is difficult. Recently, Greven and Tasman,? using the new classification, reported the results of scleral buckling in 3 stage 4B and 18 stage 5 eyes. The rate of reattachment was 100% in stage 4B and 48% in stage 5 eyes. Moreover, visual outcome greater than 20/400 was 66% in stage 4B eyes compared with II % in stage 5 eyes. In our series of IS eyes, 67% (10 of IS) were reattached with a single scleral buckling procedure. However, of these cases, only 2 of 10 (20%) were able to achieve fix and follow acuities. If one includes visual results in 4 eyes ultimately attached with vitreous surgery, still only 3 of 14 (21 %) anatomic successes in our series could fix and follow. Thus, despite the encouraging rate of anatomic success in this and other series, visual results remain disappointing even when one considers the difficulty of obtaining and interpreting visual acuity in these infants. 14.15 The reason these infants often fail to recover significant visual function despite retinal reattachment is unclear. Possible explanations include anatomic retinal abnormalities secondary to detachment and amblyopia. A retinal cause for the poor visual outcome of our infants is compelling. Clinical observations on macular development in premature infants indicate that morphologic maturity may not be present until 42 weeks of gestation. 16 Macular detachment would thus have preceded full macular development in all of our cases. The influence of detachment of an immature macula on its subsequent development is not known. Does amblyopia have a role in the visual loss of these infants? Visual deprivation experiments of von Noorden l7 and Wiesel and Hubel 18 have shown in monkeys and cats that complete occlusion for periods as brief as 2 to 4 weeks results in irreversible amblyopia when performed at less than 12 weeks of age. In these experiments, bilateral deprivation resulted in still greater irreversible anatomic abnormality along the geniculocortical pathway.19 Subsequent studies have implicated form deprivation rather
than light deprivation as the causative factor in occlusion amblyopia. Retinal detachment is clearly capable ofform deprivation and may thus exert an amblyogenic influence in ROP. The series of bilateral congenital cataracts by Rogers et al 20 demonstrated that cataract removal results in uniformly poor vision with pendular nystagmus when performed later than 10 weeks of age. The retinal detachments in our series may be subject to similar constraints. Although most of our detachments occurred between 12 and 20 weeks of age from birth, mean gestational age was only 31.5 weeks, thus within the critical period for deprivation amblyopia. No experimental data currently exist that delineates the critical period for sensory deprivation and its reversibility in premature infants. Similar concerns need to be addressed regarding duration of uncorrected refractive error postoperatively. Creation of high axial myopia with scleral buckling procedures can produce amblyopic risks similar to aphakia. The benefit of vigilant monitoring of refractive error with prompt optical correction is unknown, although this benefit is currently under investigation. Presently, no published data distinguish between retinal and preoperative or postoperative amblyopic causes for poor visual outcomes in the advanced stages ofROP. The difficulties of effectively treating the late stages of this disease will likely continue to challenge both our knowledge and surgical techniques as we aspire to intervene within a complex process of ocular and visual development.
References I. Chong LP, Machemer R, de Juan E. Vitrectomy for advanced stages of retinopathy of prematurity. Am J Ophthalmol 1986; 102:710-16. 2. Zilis JD, de Juan E, Machemer R. Advanced retinopathy of prematurity. The anatomic and visual results of vitreous surgery. Ophthalmology 1990; 97:821-6. 3. McPherson A, Hittner HM. Scleral buckling in 21/2- to 11month old premature infants with retinal detachment associated with acute retrolental fibroplasia. Ophthalmology 1979; 86:819-36.
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4. McPherson AR, Hittner HM, Lemos R. Retinal detachment in young premature infants with acute retrolental fibroplasia. Thirty-two new cases Ophthalmology 1982; 89:1160-9. 5. Topilow HW, Ackerman AL, Wang FM. The treatment of advanced retinopathy of prematurity by cryotherapy and scleral buckling surgery. Ophthalmology 1985; 92:379-87. 6. Tasman W, Brown GC, Schaffer DB, et al. Cryotherapy for active retinopathy of prematurity. Ophthalmology 1986; 93: 580-5. 7. Greven C, Tasman W. Scleral buckling in stages 4B and 5 retinopathy of prematurity. Ophthalmology 1990; 97:81720. 8. The Committee for the Classification of Retinopathy of Prematurity. An international classification of retinopathy of prematurity. Arch Ophthalmology 1984; 102: 1130-4. 9. de Juan E Jr, Shields S, Machemer R. The results of ultrasound in the management of retinopathy of prematurity. Ophthalmology 1988; 95:884-8. 10. Flynn JT, Bancalari E, Bachynski BN, et al. Retinopathy of prematurity: diagnosis, severity, and natural history. Ophthalmology 1987; 94:620-9. 11. Flynn JT. An international classification of retinopathy of prematurity. Clinical experience. Ophthalmology 1985; 92: 987-94. 12. Cryotherapy for Retinopathy of Prematurity Cooperative Group. Multicenter trial of cryotherapy for retinopathy of
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