Retina Quiz
Mourner Laments Blurred Vision
Mark T. Dunbar, O.D.A 52-year-old professional mourner noted blurred vision in both eyes. Her job entails traveling by bus to various funeral homes, where she is paid to attend funerals. But she was having difficulty reading bus signs. She does not wear glasses. She reported a new onset of flashing lights in the superior visual field of her right eye.
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| What are these bullous lesions in the peripheral retina of each eye? | |
On dilated fundus exam the vitreous was clear. She had healthy optic
nerves with small cups and good rim color and perfusion O.U. The macula
appeared normal and the vessels had normal caliber. In the periphery in
each eye there was an unusual lesion involving the inferior and inferotemporal
quadrants.
Discussion
This patient has degenerative retinoschisis in both eyes. Retinoschisis is a split between the retina’s outer plexiform and inner nuclear layers. That’s unlike a retinal detachment, which is a separation of the sensory retina from the retinal pigment epithelium. Despite the anatomical differences, it can be difficult to distinguish the two.Retinoschisis usually appears as a sharply circumscribed, smooth, immobile elevation of the inner retina extending posteriorly to the ora serrata. This transparent surface often allows you to view choroidal detail through the schisis cavity. In retinal detachment, the surface is not as smooth, but has more of a corrugated appearance. A retinal detachment will move with eye movements; retinoschisis does not. Long-standing retinal detachments often leave a demarcation line at the junction between the attached and detached retina. Depending on how long the detachment has been there, this demarcation line may appear pigmented. This alone may help distinguish the two conditions. Retinoschisis is not associated with RPE changes because only the outer layers of the retina are in contact with RPE. A retinal detachment will result in a relative scotoma, whereas patients with retinoschisis will have an absolute scotoma.
Degenerative retinoschisis occurs in up to 4% of adults and is bilateral in more than two-thirds of cases. They’re usually inferotemporal, although one study found 28% in the superotemporal quadrant.1 Cystoid degenerative changes in the retina precede peripheral retinoschisis.
There are two forms of peripheral retinal schisis: typical (flat) retinoschisis and reticular degenerative retinoschisis (the more common). Reticular schisis has a higher elevation of the inner retinal wall and extension posterior to the equator. The inner layer of reticular retinoschisis is extremely thin with attenuated blood vessels. Small yellowish-white flecks typically appear on the inner surface cavity in both forms.
Round or oval holes are often present in cases of reticular retinoschisis. Outer-wall holes are far more common than inner-layer ones, and tend to be larger and more numerous. Outer-wall holes have smooth, rounded margins and often a rolled posterior edge. Inner holes are harder to diagnosis because of the varying thickness of the inner retinal layer.
Notice in the photos a large hole in the schisis of each eye. Based on their size and rolled-edge appearance, these are outer-wall holes. Localized retinal detachments can occur in 2-6% of eyes with outer-wall holes.1 Both inner- and outer-wall holes may be necessary for progressive retinal detachment to occur. Outer-wall breaks allow fluid into the subretinal space.
This patient has a combined retinoschisis and retinal detachment in the right eye. The localized detachment doesn’t extend beyond the boundaries of the retinoschisis. In the left eye there’s only a retinoschisis with an outer-wall hole. It’s difficult to tell, but in fact the schisis in the left eye is more transparent and choroidal detail is more readily visible than in the right eye.
Many suggest that outer-layer breaks associated with retinal detachment require treatment—especially if the detachments are progressive. Percentages vary widely on the association of retinoschisis and progressive retinal detachment. Dr. Norman Byer found no cases of progressive retinal detachment in 218 eyes with asymptomatic retinoschisis, despite there being 14 eyes with localized retinal detachment; these did not progress over 9 years.1 Progressive retinal detachment is the major complication of senile retinoschisis.2
Progressive retinal detachments call for vitrectomy and scleral buckling procedures. Because of our patient’s excellent visual acuity and minimal symptoms, we decided to observe her. She has remained stable.
Degenerative retinoschisis generally is benign. Follow these patients every 6-12 months. Posterior extension occurs rarely (about 3% of eyes). Rarer still is extension into the macula. Patients with degenerative retinoschisis can present with inner- and outer-wall breaks. Outer-wall holes are much more common and are more likely associated with localized retinal detachment. In asymptomatic patients localized retinal detachments rarely progress; you can follow these without surgical intervention. Surgery for those with progressive retinal detachment associated with retinoschisis often results in flattening the retinal detachment but not the schisis cavity itself.
1. Byer NE. Long-term natural history study of senile retinoschisis
with implications for management. Ophthalmology 1986;93:1127-37.
2. Hagler WS, Woldoff, HS. Retinal detachment in relation to senile
retinoschisis. Tran Acad Ophth & Otol 1973;OP99-111.
June 15, 2000