Male infant aged 6 months (affected) and heterozygous in his mother who was seen in our clinic for presenting divergent strabismus with absence of fixation in the left eye.
Both pregnancy and delivery had passed without complications. As personal history, the infant had been involved in a traffic accident the previous month.
On examination the anterior pole was normal in both eyes.
In the left fundus there was an inferior retinal detachment associated with a vitreous veil with retinal traction up to the papilla. 

No retinal changes were observed in the right fundus.
Retinoscopy showed a neutral point of +3.00 -2.00 at 10o in the right eye and +3.50 +0.50 at 7o in the left eye.
Given the history of the traffic accident, a traumatic origin was attributed to the retinal detachment in the left eye.
Periodic check-ups were carried out. The retinal detachment evolved towards complete resorption, with a demarcation line appearing in the temporal retina. The macula adapted, presenting an alteration at the level of the retinal pigment epithelium. 

After a few months, vitreous flanges were observed in the inferior temporal arcade in the right eye. This led to the possibility of peripheral retinoschisis as the origin of the retinal detachment in the left eye.
Both macular OCT and ERG were performed, but the results could not be assessed in both tests due to the patient's poor cooperation given his young age. A DNA study was therefore performed on a peripheral blood sample. A mutation (Q154R) was observed in exon 5 of the XLRS gene responsible for X-linked retinoschisis. The mutation was present in hemizygosis in the patient (affected) and in heterozygosis in his mother (carrier).
At the age of 6 years, visual acuity was 20/20 in the right eye and 20/400 in the left eye, despite prolonged treatment with hourly occlusions of the right eye.
Examination revealed inferior temporal vitreous condensation in the right eye and inferior temporal peripheral retinoschisis in the left eye, associated with residual fibrosis of the inferior temporal arcade. 

The absence of foveal schisis was noted by OCT in both eyes.