NEWS & EVENTS
Retinal Review, Issue 73
A 35 year-old woman presented to the retinal service complaining of a scotoma in her right eye. On examination, BCVA was 20/20 ou, IOP was within normal limits. She did not have an APD OU, and anterior segment examination was unremarkable. HVF 60-4 was performed and revealed the following.
The field was consistent with an infero-nasal scotoma in her right eye. The field in her left eye showed rim artifact. The patient’s pupils were dilated and DFE revealed the following:
DFE revealed the patient had a translucent area of elevation supero-temporally in the right eye approaching the arcade. Scleral depressed examination did not reveal any full thickness retinal breaks. Scleral depressed exam of the contralateral eye revealed a similar area close to the ora serrata supero-temporally. SD-OCT of the macula was unremarkable.
The differential diagnosis in this case includes chronic rhegmatogenous retinal detachment, serous retinal detachment, choroidal effusion, or retinoschisis. In this case, the patient had bilateral retinoschisis. Her right eye was more advanced than the left eye and had outer retinal wall holes. (See arrows).
Retinoschisis is defined as a spitting of the retinal layers and comes in 2 distinct forms: degenerative retinoschisis and x-linked retinoschisis. The more common type is senile retinoschisis, in which the outer plexiform layer of the retina splits in two. The etiology is unknown. It typically presents as a transparent, smooth appearing retinal elevation. By definition, there is no full thickness break in the retina. The schisis cavity may be shallow, or quite bullous. The schisis cavity is immobile, and the surface may have a glistening appearance. Retinoschisis causes an absolute scotoma, hence our patient had an infero-nasal scotoma in HVF corresponding to the supero-temporal schisis.
Generally, retinoschisis is a benign condition, and can be observed. However, sometimes the schisis cavity may progress posteriorly. Some have advocated lasering the posterior edge of the schisis cavity to prevent its posterior progression. However, this technique has not been proven useful in the literature.
There is approximately a 20% chance of developing outer wall breaks in the schisis cavity. Even more rare, is the development of a “schisis detachment,” in which the retinoschisis converts into a retinal detachment. 0.05% of retinoschisis cases develop into RDs. The retina detaches due to the formation of an inner wall break. Liquified vitreous then enters the inner wall break, then the schisis cavity, and then accesses the subretinal space through the outer wall breaks.
Initially, our patient was observed for any signs of progression of the retinoschisis.
One year later, the patient returned and denied change in the size of the scotoma. However, DFE revealed that the appearance of the retinoschsis had changed.
There was evidence of new subneurosensory fluid posterior to the previous schisis demarcation, consistent with schisis detachment. In that year, the patient had developed an inner wall break in the schisis cavity that was not visible.
Due to the macula threatening location of the schisis detachment, the decision was made to take the patient to the operating room for repair of the schisis detachment. The patient underwent a successful pars plana vitrectomy, endolaser, air fluid exchange and gas injection for her right eye.
Post-operatively, the patient retains 20/20 vision in that eye. She still has the absolute scotoma. Post-operative funduscopic photo shows chorioretinal scarring in the area of the previous schisis cavity consistent with diffuse lasering of the area which was necessary to prevent redetachment of the retina.