Late Retinal Detachment in Patients Born Prematurely: Title and subTitle BreakOutcome of Primary Pars Plana Vitrectomy FREE

RETINOPATHY OF prematurity (ROP) is a neovascular disorder that developsin 11% to 56% of preterm infants with low birth weight.^{1 - 3} Only5% to 7% of these cases require coagulation treatment (Cryo ROP Study⁴ ). In most patients, retinal changes of the acute phaseregress completely or with residual vitreoretinal alterations.

In patients born prematurely, increased liquefaction of the vitreousand vitreoretinal traction may cause retinal detachment (RD). Characteristicretinal and vitreous pathologic conditions place these patients at increasedrisk for retinal complications throughout their lives.^{5 - 6} Retinalchanges in the posterior pole include dragging of the retina, retinal folds,and chorioretinal scarring. Neovascularization, elevated retinal vessels,cystoid degeneration, diffuse retinal pigment epithelial clumping, and retinalholes may be present in the periphery. Changes of the vitreous gel and peripheralvitreous membranes are other common findings.

To date, few published reports describe the functional and morphologicaloutcomes of patients born prematurely who develop late RD. Vitrectomy as aninitial treatment was described in 3 small series with 4 eyes each.^{7 - 9} We report the resultsof surgery for RD in 11 eyes of 10 patients with premature birth. These patientshad a birth weight lower than 1500 g or a gestational age less than 31 weeksand came to us with or without clinically visible retinal cicatricial changesof ROP.

In this study, we evaluated a consecutive series of patients born prematurelywho had RD between 1995 and 2001 and a follow-up time of at least 6 months.Only 1 of these patients was treated with cryotherapy, according to the recommendationsof the Cryo ROP Study,⁴ during the acute phaseof ROP.

Baseline ocular characteristics were obtained from clinical records.All patients had decreased vision and RD. Best-corrected visual acuity wasdocumented at baseline and the final examination. Spherical equivalent wasalso recorded at baseline for each eye. Treatment modalities for RD, the needfor multiple treatments, and interval until retreatment were noted. Characteristicsof the fundus changes were recorded at the first examination or during surgeryin cases of vitreous hemorrhage.

Characteristics of the 10 patients are listed in Table 1 and Table 2.Five of the patients were female, including 1 pair of monozygotic twins. Oneof the twins had bilateral RD. Birth weight ranged from 810 g to 1475 g, witha mean of 1128 g and a median of 1073 g. Gestational age ranged from 26 to30 weeks, with both a mean and median of 28 weeks. The age at first retinalsurgical procedure ranged from 9.9 to 42.4 years, with a mean of 22 yearsand a median of 15.4 years. The mean follow-up time was 2.7 years with a rangeof 0.6 to 6.6 years.

Baseline spherical equivalent refraction was present in all patients.Myopia was found in 9 of 11 eyes. The mean refractive error for all eyes was−8.6 ± 7.0 diopters (D), with a median of –8.5 D and arange of 0.75 to –17.6 D.

All eyes had RD and vitreoretinal interface changes. Retinal breakswere located posterior to the equator or at the edge of the staphyloma inthe eyes with high myopia. Two patients initially had vitreous hemorrhage,with RD detected at an ultrasound examination. Distribution of fundus characteristicsat first examination appears in Table 3. Five eyes had an abnormal retinal vessel angle, macular ectopia,and mild peripheral vitreoretinal changes. Three of these were highly myopic.Three additional eyes had severe cicatricial retinal changes with tractionalRD. Another patient had a retinal fold. Two eyes were initially aphakic asa result of surgery for congenital cataract. One patient was treated withcryotherapy during the acute phase of stage 3+ ROP. This boy developed vitreoushemorrhage with RD after experiencing blunt trauma at age 9 years. No characteristicsof traumatic RD were seen, but a retinal break with vitreoretinal tractiondeveloped anterior to the scars caused by coagulation treatment. Severe retinalchanges due to residual stages of ROP were present in 6 contralateral eyes,2 of which had no light perception because of the disease.

All patients complained of acute visual loss. Distribution of visualacuity before surgery and at the final examination is shown in Figure 1. Vision improved after surgery in 8 eyes and decreasedin 3 eyes. Poor visual outcome occurred in eyes with recurrent RD or the developmentof optic atrophy.

Treatment for RD was performed with general anesthesia. During the firstoperation, all eyes underwent pars plana vitrectomy, in 1 eye, an additionalencircling band was performed. Sulfur hexafluoride (SF6) was used in 7 eyesas an intraocular tamponade, and silicone oil was used in 4 eyes with moresevere vitreoretinal abnormalities. A complete retinal attachment was obtainedin 7 eyes after a single procedure (6 with SF6 and 1 with silicone oil). In1 additional eye, the macula was attached with silicone oil tamponade. Furthersurgery including removal of the silicone oil was not considered owing tooptic atrophy and a persistent peripheral RD or retinal fold.

Retinal redetachment occurred in 3 eyes. In 2 of these eyes, the redetachmentwas due to proliferative vitreoretinal traction under the silicone oil tamponadewith secondary breaks on the equator in one eye and posterior to the equatorin the other. In these 2 eyes, tractional membranes were removed in a secondvitrectomy procedure, and a repeated silicone oil tamponade was used. In 1of the 2 eyes, a second redetachment was treated with an encircling band,and the silicone oil was finally removed during another operation. The secondof these 2 eyes developed recurrent tractional RD even with silicone oil tamponade.Prior to the fifth surgical procedure, the eye began to develop phthisis;after this surgery, the retina remained attached. Although the phthisis didnot progress for 3½ years, the eye later developed optic atrophy. Therefore,we decided not to remove the silicone oil. The third eye with a redetachmentwas primarily treated with SF6. This RD was due to retinal traction and anew retinal hole and occurred after gas absorption. In the second operation,silicone oil was used. After 6 months of follow-up, the retina is attachedand silicone oil removal is scheduled.

In 10 (90.9%) of 11 eyes, the retina was completely attached at thelast follow-up visit. In the remaining eye, only the macula was attached.Four eyes still had a silicone oil tamponade.

In our study, a secondary cataract developed in 3 eyes. One of thesepatients was an 11-year-old boy with a primary silicone oil tamponade. Thesilicone oil was removed 6 months after primary surgery. Eight months latera secondary cataract developed, and surgery was performed with intraocularlens implantation. The other 2 patients were aged 36 and 39 years at primarytreatment. In both cases, SF6 tamponade was used during primary surgery. Oneof these patients developed a redetachment, and silicone oil was used in thesecond operation. It was removed 6 months later in combination with cataractsurgery. In both adults, cataract surgery was performed with intraocular lensimplantation.

Three eyes with permanent silicone oil tamponade were either aphakicinitially (n = 2) or the lens was removed during primary surgery (n = 1) becauseof anterior traction. No patient younger than 26 years with SF6 tamponadedeveloped a secondary cataract. Follow-up for these patients was 0.9 to 6.6years (median, 2.6 years).

With advances in neonatology, the number of prematurely born childrensurviving and reaching adulthood is expanding. Premature birth increases therisk of retinal tears or RD.⁷ In our study,we report the results of surgery for RD in 11 eyes of 10 patients born prematurelywho ranged in age from 9 to 42 years. The characteristic appearance of thepremature fundus included myopic changes, tortuous retinal vessels, temporaldragging of the vessels, macular ectopia, retinal folds, pigmentation of theretina, and in 1 case chorioretinal scars due to coagulation treatment duringan acute phase of ROP.

One eye had been treated with transscleral cryotherapy for stage 3+ROP. This eye developed RD after blunt trauma. Greven and Tasman¹⁰ described3 eyes with rhegmatogenous RD 1 to 3 years after cryotherapy for stage 3+ROP. After a scleral buckling procedure, 2 of 3 eyes were anatomically reattached,but only 1 eye developed useful vision.

In our study, all eyes were treated with primary vitrectomy. In 1 eye,an additional scleral buckling procedure was performed during primary surgery.In 3 (27.3%) of 11 eyes, the initial treatment failed and additional procedureswere required. These treatment failures were observed in the 2 eyes with themost severe vitreoretinal traction, due to cicatricial ROP, and in 1 eye withstrong adherence of the vitreous cortex.

In older reported series vitrectomy was not available, and only a scleralbuckling procedure was used in the treatment of RD associated with regressedROP. These studies show final success rates of 63% (5 of 8 eyes),¹¹ 87% (34 of 39 eyes),¹² 88%(14 of 16 eyes),¹³ and 94% (15 of 16 eyes).¹⁴ The good results of some of these studies may beowing to the exclusion of inoperable eyes with vitreoretinal traction. Harris¹³ described 52 eyes with late RD and a cicatricialstage of ROP; 13 of these eyes were considered inoperable because of severevitreoretinal involvement.

Sneed et al⁹ treated 16 eyes with late-onsetRD associated with regressed ROP. All of their patients demonstrated temporalstraightening of the retinal blood vessels and diffuse retinal pigment epithelialclumping. The initial scleral buckling procedure had a failure rate of 50%.Eight eyes were operated on with pars plana vitrectomy techniques (4 as aprimary procedure). After long-term follow-up (6 months), 14 (87.5%) of the16 treated eyes were successfully reattached. The authors concluded that parsplana vitrectomy in conjunction with scleral buckling may be necessary toachieve long-term retinal reattachment.⁹ Ofthe 31 eyes with RD treated by Kaiser et al,⁷ 26were treated with primary scleral buckling, 3 with primary vitrectomy, and2 with vitrectomy plus scleral buckling. They reported initial treatment failurein 5 (16%) of the 31 eyes. All 5 eyes were treated initially with a scleralbuckling procedure. Although there were no failures in the primary vitrectomywith scleral buckling group, there was no statistical difference between the2 groups because of small numbers. Despite the small sample sizes, these authorsconcluded that scleral buckling alone may be inadequate in many eyes to relievevitreoretinal traction. They suggest primary vitrectomy combined with scleralbuckling as initial treatment for late RD caused by ROP. In our study, anadditional scleral buckling procedure for reattachment was performed in only1 eye.

Tasman^{5 ,11 ,14} describedvitreoretinal changes in cicatricial retrolental fibroplasia. He detectedround or oval breaks and suggested that cicatricial retrolental fibroplasiais a progressive disease caused by vitreoretinal adhesions. He concluded thatprimary vitrectomy is the only way to approach these vitreoretinal changesand that silicone oil may sometimes be necessary.¹⁵ Machemer⁸ reported 4 cases of late tractional RD that occurredin eyes with cicatricial ROP. All of these eyes had temporal dragging of theretinal vessels. He treated this kind of RD successfully with primary vitrectomy.The results of our study indicate that late RD in patients born prematurelycan be successfully treated with pars plana vitrectomy. Silicone oil tamponadeand additional scleral buckling may be needed in more severe cases.

Retinal detachment is a possible complication of regressed ROP. It isuncertain whether retinal breaks and RD in regressed ROP are secondary toongoing changes of ROP, to abnormal vitreoretinal interface changes causedby ROP, or to other unrecognized factors. Tasman⁵ speculatedthat as a result of vitreous traction, retinal vessels sometimes pulled intothe vitreous cavity because of shrinking vitreous gel. He implied that temporalvitreous traction on the retina is the rule and proposed that this occursbecause the temporal retina, even in full-term infants, is the last area tobecome vascularized and is thus more sensitive to changes in oxygen concentration.That vitreous gel may partially liquefy and form syneresis cavities may alsobe important. Between these cavities, the vitreous fibrils condense and mayinsert into the retina. Thirteen years later, Sebag¹⁶ describedage-related differences in the human vitreoretinal interface. He found thatin 40% of eyes of individuals 20 years or younger, adhesion between the internallimiting membrane and the posterior vitreous cortex was stronger than thatof the Müller cells. Consequently, in his study of dissection of thevitreous from the retina, the inner portions of the Müller cells toreaway from the retina and adhered to the internal limiting membrane–vitreouscortex complex. If the process of liquefying occurs without adequate dehiscencebetween the vitreous cortex and the internal limiting membrane, traction willbe exerted at sites of persistent adhesion and may cause retinal tears. Sebagpresumed that this may be the reason for severity in patients with high myopiaand vitreous degeneration in whom liquefaction is advanced but there is novitreoretinal dehiscence.

In our study, 6 eyes of 7 patients younger than 20 years were highly(6 D) myopic. In some cases, a strongly adherent vitreous cortex was notedduring surgery. Vitreoretinal changes due to high myopia or premature birthmay cause RD. Abnormal vitreoretinal traction may be another factor in thedevelopment of RD.

Machemer⁸ obtained specimens for histologicalexamination during vitrectomy. The membranes in the vitreous cavity were collagenrich and contained cells with glial characteristics. He assumed that chronicexudation from vascular abnormalities was the stimulus for this proliferation.In addition, high myopia and frequent latticelike changes placed these patientsat a higher risk for RD.

We recommend that patients with premature birth should be informed aboutthe possibility and symptoms of RD. Those born prematurely, with or withoutsignificant fundus changes, should be monitored regularly for retinal complications.When RD occurs, primary vitrectomy without scleral buckling can be used forsuccessful reattachment of the retina.

Corresponding author and reprints: Claudia Jandeck, MD, UniversityEye Clinic, Universitätsklinikum Benjamin Franklin, Freie Universität,Berlin, 12200 Berlin, Germany (e-mail: jandeck@zedat.fu-berlin.de).

Submitted for publication January 14, 2003; accepted June 9, 2003.