Juvenile Retinoschisis Workup

Updated: May 02, 2017
  • Author: Leslie Small, OD; Chief Editor: Donny W Suh, MD, FAAP  more...
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Workup

Imaging Studies

Red-free illumination fundus examination and photography can help reveal subtle foveal schisis that may be difficult to visualize with ophthalmoscopy. [3]

Optical coherence tomography (OCT) provides high-resolution cross-sectional images of the macular region. In individuals with X-linked juvenile retinoschisis (XLRS), OCT reveals cystic spaces primarily in the inner nuclear and outer plexiform layers of the retina.

OCT can be useful in differentiating retinoschisis from retinal detachment. OCT may be limited by reflectivity from dense hemorrhage, which may interfere with the visualization of the retina. The view of the periphery using OCT is somewhat limited. However, wide-field spectral-domain OCT (SD-OCT) imaging may augment the ability to capture peripheral schisis.

Fluorescein angiography (FA) does not aid in the diagnosis of X-linked juvenile retinoschisis. However, FA can help differentiate foveal schisis cavity from cystoid macular edema. In X-linked juvenile retinoschisis, the angiographic results are normal, whereas in cystoid macular edema, late hyperfluorescence in a petaloid pattern is seen. Peripheral areas of nonperfusion can also be seen.

Indocyanine green (ICG) angiography performed on patients with X-linked juvenile retinoschisis shows a distinct hyperfluorescence in the macular region that is associated with radial lines of hypofluorescence centered on the foveola in the early phase. This feature disappears in the late phase of the ICG angiography. 

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Other Tests

Electroretinogram (ERG) can be used as a diagnostic tool (see image below).

Electroretinogram of a patient with juvenile retin Electroretinogram of a patient with juvenile retinoschisis.

In recessive X-linked juvenile retinoschisis, ERG findings show negative-shaped responses (eg, normal a-wave, reduced b-wave). Normally, the b-wave has a greater amplitude than the a-wave. In recessive X-linked juvenile retinoschisis, the b-wave amplitude does not rise up to the level where the a-wave began. With age and increasing atrophy of the retinal pigment epithelium, a-wave and b-wave amplitudes may both be reduced. However, a negative ERG is not unique to XLRS; it is seen in several acquired retinal disorders. [3]

ERG dysfunction is found throughout the retina and is not limited to schitic areas. Therefore, both focal and macular ERG and full-field ERG yield similar results.

The electro-oculography findings are normal in young patients, and it is not a useful tool in the late stages as the light peak-to-dark trough ratio deteriorates. The visual-evoked response exhibits delayed peak times consistent with abnormal macular function.

DNA sequencing of the XLRS1 gene can be a useful to confirm the diagnosis.

The mutation in RS1 can be detected in 90%-95% of patients who have a clinical diagnosis. It not only helps confirm the diagnosis but also provides useful information for genetic counseling of the patient and offspring. Females who are at risk of being carriers of the mutation may also be offered genetic testing and counseling. [3]  

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Histologic Findings

 X-linked juvenile retinoschisis results from splitting of the inner retina, primarily within the nerve fiber layer in the fovea and in the periphery. Splitting may also occur within the ganglion cell layer or the internal limiting membrane. A filamentous, extracellular material with features consistent with a Muller cell origin has been described within the retina.

 An analysis of an undiluted sample of intraschisis fluid obtained during surgical repair of a patient with X-linked juvenile retinoschisis revealed the presence of two proteins. They were tenascin-C, an extracellular matrix protein involved in wound healing, and cystatin C, an ubiquitous cysteine protease inhibitor implicated in inflammation. 

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