Retinoschisis
 

This is a common case for indirect ophthalmoscopy using a 20D. There is a dome-shaped, smoothly elevated transparent lesion in the peripheral retina. Most commonly seen in the upper temporal quadrant. There are holes on the lesions. Other signs: examine the opposite eyes for similar lesion look at the patient's glasses as 70% of them are hypermetropic.

Questions:

1. How does retinoschisis develop?

Answer

The degenerative type of retinoschisis is thought to arise from coalescence and extension of the cavities of peripheral cystoid degeneration.

 

2. What are the types of retinoschisis?

Answer

In degenerative retinoschisis the retina is split in the outer plexiform layer. In reticular  retinoschisis (less common) the splitting occurs in the nerve fibre layer.

 

3. How can retinoschisis be differentiated from retinal detachment?

Answer

The following sings are seen in retinal detachment which are absent in retinoschisis:

tobacco dust and or haemorrhage in the vitreous
a corrugated and irregular surface
atrophy of the underlying retinal pigment epithelium
demarcation line and macrocysts
The visual field shows relative scotoma in retinal detachment but absolute scotoma in retinoschisis.
Laser photocoagulation will create a burnt in retinoschisis but not in retinal detachment because of the presence of subretinal fluid which prevent the burning of the retinal pigment epithelium.

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