Autosomal recessive inheritance.
There is substitution of valine for glutamine in the 6th position on
the beta chains of the haemoglobin molecules.
c. What ocular signs may be present?
The following signs are specific to patient with sickle cell
comma-shaped conjunctival vessels
- sea-fan lesions in the peripheral retina
- vitreous haemorrhage
- salmon patches (results from intraretinal and subretinal
- black sun bursts (commonly follows salmon patch and
results from RPE hyperplasia)
- tractional retinal detachment
- angioid streaks
- macular ischaemia
- central retinal artery and vein occlusion
- rhegmatogenous retinal detachment