Statistics from Altmetric.com
Acquired retinoschisis affects 7% of people aged >40 years and is bilateral in 85%.1,2 Although retinoschisis is generally asymptomatic and stable, retinal detachment can supervene in one of three ways. Two of these are rare, are associated with posterior vitreous detachment (PVD), and justify surgical correction; thus, a retinal tear and detachment may originate within non-schitic retina or open breaks in the inner leaf of a schisis may allow fluid vitreous to be recruited into the cyst and thence to pass through breaks in the outer leaf, causing it to separate from the retinal pigment epithelium (RPE) over a wide area. The third mechanism—“schisis detachment”—is quite common (for example, 9% prevalence in Byer’s series2) and reflects the opening of outer leaf breaks alone. No fluid vitreous gains access to the cyst or subretinal space whether or not inner leaf breaks are present. Schisis detachments remain relatively localised owing to the viscous nature and limited volume of cyst fluid,3 and the action of the RPE pump can eventually lead to reattachment of the retina and collapse of the cyst. Byer’s natural history studies resulted in his recommending that surgery for schisis detachments be limited to eyes withsymptomaticprogression.2,3 We present a patient with sequential bilateral schisis detachments, each of which was symptomatic at onset but which settled spontaneously.
In March 2000 a 46 year old man was referred with a 2 day history of photopsia and a disturbance in the upper part of the visual field in his right eye. Visual acuity was 6/5 unaided in each eye, and neither eye had a PVD. Funduscopy revealed a schisis detachment inferiorly in the right eye with a curvilinear outer leaf break at the posterior limit of the cyst (fig 1A). The detachment extended midway between the main inferotemporal branch retinal artery and the fovea. The full thickness of retina delineating the superotemporal edge of the outer leaf break had a sawtooth pattern of outer retinal shagreen, while the free inferonasal edge of the break was rolled over. The oedema resolved within a week and no surgical intervention was recommended, merely observation. A bullous inferotemporal retinoschisis was also noted in the left eye, extending almost to the major vascular arcade (fig 1B). During 3 years of follow up, a clinically obvious decrease in the height of the cyst and spontaneous closure of the outer leaf break were observed in the right eye, RPE atrophy indicating the extent of previous retinal detachment (fig 1C and E). Right vision has remained 6/5 albeit with visual field loss superiorly.
In November 2001, photopsia and visual field disturbances were experienced in the left eye. Examination revealed a curvilinear outer leaf break at the posterior limit of the inferotemporal cyst (fig 1D). The associated schisis detachment encroached upon, but did not involve, the left fovea. Given the patient’s history, surgery was considered unnecessary. Again the retinoschisis cavity deflated and subretinal fluid slowly absorbed leaving RPE atrophy in its wake (fig 1F). Left vision has remained 6/5 but with an absolute superonasal scotoma.
Most outer leaf breaks develop well within the confines of a retinoschisis, and cyst fluid separates the RPE and outer leaf only in the immediate vicinity of the breaks.3 However, the giant outer leaf breaks responsible for the schisis detachments in our patient were each located at the posterior limit of a large retinal cyst. It is unsurprising, therefore, that the detachments progressed beyond the retinoschisis and were symptomatic.
This is the first report of symptomatic schisis detachments that settled without surgery. We agree with Byer2,3 that the appropriate management for non-progressive schisis detachments is “to do nothing,” and believe this policy can be extended to symptomatic, inferior schisis detachments that do not involve the fovea. Surgical intervention, including retinopexy around the breaks, might well have induced sight threatening complications in our patient2,4,5 while offering no real prospect of a better outcome or prognosis.