Typical (Flat) Retinoschisis

Overview

A typical retinoschisis presents as retinal splitting within the outer plexiform layer and is thought to occur due to the coalescence of cysts in peripheral cystoid degeneration. A typical retinoschisis is shallow, round or oval in shape and is found anterior to the equator. They are usually bilateral and are most commonly found in the inferotemporal retina.

Shallow retinoschisis may be difficult to detect, particularly on non-stereoscopic widefield imaging. Some clues include the presence of a mild haze partially obscuring choroidal detail and diversion of the blood vessels due to elevation of the inner retinal layers. Retinal blood vessels within an area of retinoschisis may also appear darker in colour than surrounding vessels.

OCT shows retinal splitting at the level of the outer plexiform layer.

Other associated clinical findings may include areas of capillary non-perfusion, telangiectasia and retinal haemorrhages. Retinal holes or detachments are rare in the typical form of retinoschisis.

Case Examples

  • Case 1

    A 47 year old asymptomatic Asian female with best corrected visual acuity of 6/6 (20/20) in the right eye.

    Optomap and green separation images (right inferotemporal retina)

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    Optomap and green separation images (right inferotemporal retina)

    Widefield imaging shows an area of peripheral cystoid degeneration. The associated retinoschisis is difficult to identify on widefield imaging alone in this patient.

    Spectralis OCT line scans taken through (1) and at the border (2) of the area of cystoid degeneration

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    Spectralis OCT line scans taken through (1) and at the border (2) of the area of cystoid degeneration

    OCT through the area of cystoid degeneration (1) shows retinoschisis and numerous intraretinal hyper-reflective dots. An OCT line scan taken at the posterior edge of the cystoid degeneration shows a shallow splitting of the retina at the level of the outer plexiform layer.

    Optomap and green separation images (left inferotemporal retina)

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    Optomap and green separation images (left inferotemporal retina)

    Imaging shows an area of peripheral cystoid degeneration in the left inferotemporal retina The associated retinoschisis is difficult to identify again, but in this eye, the green separation image gives an indication of the edge of the retinoschisis (there is a subtle colour variation posterior to the area of cystoid degeneration).

    Spectralis OCT line scans taken through (1) and at the border (2) of the area of cystoid degeneration

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    Spectralis OCT line scans taken through (1) and at the border (2) of the area of cystoid degeneration

    OCT through the area of cystoid degeneration shows a splitting of the retinal layers with hyper-reflective dots, similar to the right eye. An OCT line scan taken posterior to the area of cystoid degeneration also shows a shallow splitting of the retina (schisis). The edge of the retinoschisis is coincident with the edge seen on Optomap imaging.

  • Case 2

    An asymptomatic 70 year old Caucasian female with best corrected visual acuity of 6/6 (20/20).

    Optomap and green separation images (right supero-temporal retina)

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    Optomap and green separation images (right supero-temporal retina)

    Widefield imaging shows an area of peripheral cystoid degeneration with an adjacent retinoschisis and retinal tear. The flap of the tear is surrounded by a redder border and the edge of the retinoschisis can be identified by the blue arrows.

    Spectralis OCT line scans through the region of interest

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    Spectralis OCT line scans through the region of interest

    OCT through the superotemporal retina (1) shows a retinoschisis and numerous hyper-reflective intraretinal dots.

    A scan taken through the retinoschisis, adjacent to the retinal hole (2) shows the schisis and a localised retinal detachment.

    A scan taken through the retinal tear (3 and 4) shows the flap of torn retina with an associated retinal detachment. Cystoid degeneration can be seen adjacently.

References

Thanos, A., Todorich, B., Pasadhika, S., Khundkar, T., Xu, D., Jain, A., Ung, C., Faia, L. J., Capone, A., Williams, G. A., Yonekawa, Y., Sarraf, D., & Wolfe, J. D. (2019). Degenerative Peripheral Retinoschisis: Observations From Ultra-Widefield Fundus Imaging. Ophthalmic Surgery, Lasers & Imaging Retina, 50(9), 557-564.

Wallsh, JO, Gallemore,RP (2017) Identifying rhegmatogenous detachments in bullous retinoschisis with optical coherence tomography studies, American Journal of Ophthalmology Case Reports, Volume 6, Pages 38-40