Retinoschisis is an eye condition where the retina, the light-sensitive tissue at the back of the eye, splits into two layers. This separation can occur in different parts of the retina, potentially affecting vision depending on the location and extent of the split. Optical Coherence Tomography (OCT) is a precise, non-invasive imaging technology that plays a significant role in diagnosing and managing this condition. It offers detailed cross-sectional views of the retinal layers.
Understanding Optical Coherence Tomography
Optical Coherence Tomography (OCT) is an advanced imaging system that uses light waves to generate detailed images of the eye’s internal structures. It bounces invisible red light off the retina, measuring reflections to construct high-resolution, cross-sectional views. This allows examination of each retinal layer with near-cellular precision.
The OCT scan is straightforward and comfortable. It is non-invasive and typically takes 5 to 10 minutes per eye. Patients rest their chin on a support and look at a fixed target while the machine scans the eye without physical contact. Sometimes, eye drops may be used to dilate pupils for a clearer view, which can cause temporary light sensitivity.
Visualizing Retinoschisis on an OCT Scan
An OCT scan reveals the characteristic separation of the retinal layers in retinoschisis. On the cross-sectional image, this appears as a clear space or “schisis cavity” within the retina. OCT can identify which retinal layers are involved.
In degenerative (senile) retinoschisis, affecting older adults, the splitting often occurs in the outer plexiform layer. It appears as a smooth, dome-shaped elevation of the inner retinal layers, sometimes with fine, glistening dots. Juvenile X-linked retinoschisis, a hereditary form affecting younger males, frequently involves the inner nuclear layer or ganglion cell layer, and often presents with tiny intraretinal cysts, sometimes forming a “spoke-wheel” pattern. OCT may also show darker vessels over the affected area due to shadowing.
Differentiating from Retinal Detachment
Distinguishing retinoschisis from a rhegmatogenous retinal detachment is important for OCT, as both conditions can cause retinal elevation but require different management. On an OCT scan, retinoschisis is characterized by a splitting within the neurosensory retina, with inner and outer retinal layers connected by bridging fibers. Fluid in a schisis cavity is contained within the retinal layers.
In contrast, a retinal detachment involves the separation of the neurosensory retina from the underlying retinal pigment epithelium (RPE). On OCT, this appears as a distinct, often undulating, separation between the retina and the RPE, with subretinal fluid. Unlike retinoschisis, detachment usually involves a retinal tear or break, allowing fluid from the vitreous cavity to collect underneath. This anatomical distinction on OCT helps prevent misdiagnosis and guides treatment.
Monitoring Disease Progression and Complications
After diagnosis, OCT scans monitor retinoschisis long-term, as many cases are observed rather than treated. Regular OCT scans track the stability and size of the schisis cavity. This helps determine if the condition is stable or changing.
OCT can also detect complications like inner or outer retinal holes within the schisis cavity. These breaks can lead to a “schisis detachment,” where fluid extends into the subretinal space, or even a rhegmatogenous retinal detachment if both layers break. Monitoring with OCT is important for preserving vision and indicating when intervention is necessary.