Giant tear dialysis in the outer layer of retinoschisis

Diagnosis and Management of Degenerative Retinoschisis and Related Complications

Degenerative retinoschisis is a common condition characterized by elevation of the inner layers of the peripheral retina. While uncomplicated retinoschisis (i.e. with no associated retinal layer breaks) is almost invariably a benign process, retinal detachment associated with isolated outer layer breaks (termed schisis-detachment) is fairly common. Historically, schisis-detachment has been treated with a variety of interventions ranging from retinopexy to intraocular surgery. Based on published descriptions of the natural history of the disease, these interventions are likely unnecessary in many cases and may place the patient's vision at unnecessary risk. Progressive symptomatic schisis-related retinal detachment, on the other hand, is a vision threatening condition that requires intervention. While clinical examination remains the mainstay of diagnosis, recent advances in multimodal imaging can provide supplemental information in subtle cases and may prove valuable for long-term disease monitoring. When evaluating patients with peripheral retinal elevation, it is important for ophthalmologists to make an accurate diagnosis and understand the risk-benefit ratio associated with intervention. Thus, we summarize the current literature on the natural history, clinical and imaging diagnosis, and surgical management of degenerative retinoschisis and its related complications.

Giant retinal tears

A giant retinal tear (GRT) is a full-thickness neurosensory retinal break that extends circumferentially around the retina for three or more clock hours in the presence of a posteriorly detached vitreous. Its incidence in large population-based studies has been estimated as 1.5% of rhegmatogenous retinal detachments, with a significant male preponderance, and bilaterality in 12.8%. Most GRTs are idiopathic, with trauma, hereditary vitreoretinopathies and high myopia each being causative in decreasing frequency. The vast majority of GRTs are currently managed with a pars plana vitrectomy; the use of adjunctive circumferential scleral buckling is debated, but no studies have shown a clear anatomical or visual advantage with its use. Similarly, silicone oil tamponade does not influence long-term outcomes when compared with gas. Primary and final retinal reattachment rates are achieved in 88% and 95% of patients, respectively. Even when the retina remains attached, however, visual recovery may be limited. Furthermore, fellow eyes of patients with a GRT are at higher risk of developing retinal tears and retinal detachment. Prophylactic treatment under these circumstances may be considered but there is no firm evidence of its efficacy at the present time.

OUTCOMES OF SURGERY FOR PROGRESSIVE SYMPTOMATIC RETINAL DETACHMENT COMPLICATING RETINOSCHISIS

PURPOSE

To select the best surgical technique and predict the surgical success in cases of progressive symptomatic retinal detachment complicating retinoschisis (PSRDCR).

METHODS

Cases were divided into three groups: group I, those with outer layer breaks (OLBs) positioned anterior to the equator and no proliferative vitreoretinopathy (PVR); group II, those with OLB(s) at or posterior to the equator and no PVR at presentation; and group III, PVR greater than grade B at presentation. A retrospective study of 30 such eyes presenting to the authors and a review of the 47 previously reported cases to which the three-group anatomical classification might be applied were performed.

RESULTS

In group I, the overall primary and final success rates were 85% (17/20) and 95% (19/20), respectively. In group II, the corresponding data were 67% (34/51) and 94% (48/51), respectively. Group III eyes fared badly with primary and final success rates of 0 (0/6) and 17% (1/6), respectively.

CONCLUSION

The overall 66% primary anatomical success rate was lower than those reported in most series of rhegmatogenous retinal detachment uncomplicated by retinoschisis. In group I, the surgical technique used had no detectable influence on outcome. Vitrectomy appears to have been the procedure of choice in group II, but a significant P value could not be demonstrated to support it (Yates corrected chi test, P = 0.84). This study, however, had very low power with which to investigate for such effects. PVR greater than grade B at presentation was not previously been recognized in cases of PSRDCR and when present was associated with very poor primary and final reattachment rates.

Senile schisis detachment with posterior outer layer breaks

BACKGROUND

Senile retinoschisis with associated retinal detachment in the presence of multiple or large posterior outer layer breaks is rare. Despite many and significant developments in vitreoretinal surgery for this situation, no definitive therapeutic guidelines exist. In an observational study three different approaches performed by two of the authors are presented.

METHODS

Eighteen eyes of 18 patients with symptomatic schisis detachment and large posterior outer layer breaks were analyzed retrospectively. The fovea was detached in six eyes. Four eyes had laser photocoagulation and/or transscleral cryopexy (Group I), and five eyes had extensive scleral buckling (Group II). In nine eyes primary vitrectomy and gas endotamponade were performed, including inner layer resection in two eyes (Group III). The median follow-up period was 13 months.

RESULTS

Initial anatomic success, which was defined as complete reattachment of the outer retinal layer, was achieved in two of four eyes of Group I, in four of five eyes of Group II, and in seven of nine eyes of Group III. Inner layer separation persisted in 11 of 16 eyes. Visual acuity improved in 3 of 18 eyes, remained unchanged in 9 of 18 eyes, and worsened in 6 of 18 eyes. Complications included in Group I were persistent outer retinal layer detachment (two eyes); in Group II, proliferative vitreoretinopathy (PVR) detachment (one eye), CME (one eye), diplopia (one eye), late redetachment (one eye); in Group III, secondary rhegmatogenous detachment (one eye) PVR detachment (two eyes), macular pucker (one eye), preexisting CME (two eyes), subretinal perfluorocarbon liquid (one eye), transient central serous detachment (one eye), and nuclear sclerosis (five of eight eyes).

CONCLUSION

Photocoagulation alone may be considered a first approach in selected cases of schisis detachment complicated by large posterior outer layer breaks. By use of present surgical techniques, today pars plana vitrectomy is the most rational approach allowing an exact evaluation of the complex retinal architecture, a controlled coagulation, and an adequate tamponade of the involved area. Resection of the inner layer seems to increase the risk for epiretinal membrane formation.

Symptomatic retinoschisis-detachment involving the macula

We treated three patients (four eyes) in whom posteriorly situated retinoschisis-detachments became symptomatic because of elevation of a limited area of full-thickness retina at the macula adjacent to these lesions. Laser photocoagulation alone was successful in achieving long-term macular reattachment in one eye but failed in both eyes of a bilaterally affected patient. In this patient, retinal cryopexy, external drainage of subretinal and retinoschisis cavity fluid, and intravitreal air injection attained long-term macular reattachment and retinoschisis cavity collapse in both eyes. In the third patient, cryopexy, drainage of subretinal and retinoschisis cavity fluid, and scleral buckling failed to reattach the retina. Subsequent laser photocoagulation induced reabsorption of subretinal fluid but without retinoschisis cavity collapse. Alternative management strategies for these unusual cases include retinal cryopexy alone and vitrectomy techniques.

Pars plana vitrectomy in the management of retinal detachments associated with degenerative retinoschisis

Pars plana vitrectomy and gas-fluid exchange were used to successfully reattach eyes of 12 patients who had symptomatic retinoschisis retinal detachments (RDs) associated with large or posterior outer-layer holes. Visual acuity improved postoperatively in seven (58%) eyes, was unchanged in two (17%) eyes, and decreased in three (25%) eyes. Loss of vision was secondary to a mild posterior subcapsular cataract in one eye and to epiretinal membranes in the other two. In two other eyes, cataracts developed that subsequently required an extracapsular cataract extraction (ECCE) and posterior chamber intraocular lens (PC IOL) implantation with 20/20 visual acuity in both eyes after cataract surgery. All eyes with a macula-involved RD stabilized or improved in visual acuity. Surgical indications, techniques, and results in the management of these retinoschisis RDs are discussed.

The management of retinal detachment complicating degenerative retinoschisis

We repaired six retinal detachments complicating degenerative retinoschisis by using simultaneous external subretinal fluid drainage and intraocular gas injection without a scleral buckle or vitrectomy. The outer wall breaks were 30 to 135 degrees in size, and in three cases, extended close to the arcade vessels. We achieved retinal reattachment and collapse of the schisis cavity at surgery in all six cases. In one case, the retina redetached postoperatively, but it was repaired with a scleral buckle and gas injection. This technique simplified the management of retinal detachments complicating degenerative retinoschisis, particularly those with large or posterior outer-layer breaks.

Degenerative retinoschisis with giant outer layer breaks and retinal detachment

Five unusual cases of retinal detachment were caused by giant (more than 90 degrees) posterior breaks in the outer layer of degenerative retinoschisis. All retinas were successfully reattached by a variety of surgical techniques. The two cases managed with scleral buckling required subsequent buckle removal because of macular distortion. Treatment with cryotherapy or laser, together with intraocular air and postoperative positioning, gave better anatomic results.