Although ischemic changes may be apparent on the retina, maculopathy may be asymptomatic at first leaving visual acuity unchanged. Central retinal artery occlusion is a known feature of non-proliferative sickle cell retinopathy that has a low incidence in patients with non proliferative sickle cell retinopathy. Optic nerve sign is represented by dilated capillaries that can be visualized in the nerve using fluorescein angiography. Visual acuity often remains unchanged with this finding. Angioid streaks: Angioid streaks may be seen in up to 6% of cases. Proliferative sickle cell retinopathy (PSCR)
Proliferative sickle retinopathy is the most severe ocular complication of sickle cell disease. Even though PSCR begins in the first decade of life, the condition remains asymptomatic and unnoticed until visual symptoms occur due to vitreous hemorrhage or retinal detachment. Goldberg classification
Goldberg classified PSR into following 5 different self-explanatory stages:

Stage of peripheral arterial occlusion and ischemia: It is the earliest abnormality that can be visualized by fundus examination. The occluded arterioles can be seen as dark red lines. They eventually turn into white silver-wire vessels. Stage of peripheral arteriolar-venular anastomoses: Arteriolar-venular anastomoses develop as blood is diverted from blocked arteries to nearby venules. Stage of neovascularization and fibrous proliferation: Neovascularization starts from the arteriolar-venular anastomoses, and grow into the ischemic retina. Characteristic fan-shaped appearance due to neovasularization is known as sea fan neovascularization. Stage of vitreous hemorrhage. Peripheral neovascular tufts bleed and cause vitreous hemorrhage. Stage of vitreoretinal traction bands and tractional retinal detachment: Traction on the sea fan and adjacent retina causes traction retinal detachment.
Bevacizumab is an anti-VEGF drug used in intravitreal injection that is known to cause reversal of sea fan lesions and reduce the duration of vitreous hemorrhage. Intravitreal injection of anti-VEGF drugs can also be used prior to surgery to aid separation of tissues involved in the sea fan lesion and to reduce intraoperative and postoperative hemorrhage. It is useful in combination with photocoagulation. Laser
Indications for laser photocoagulation include
Peripheral neovascularization of upwards of 60° circumference
Sickle cell retinopathy affecting both eyes
Large elevated sea fans
Rapid progression of neovascularizationThere are two methods of photocoagulation mainly used; feeder vessel coagulation and scatter laser coagulation. The first method closes the vessels that supply the neovascularized areas using laser burns. Both the xenon arc and argon laser can be used however, the argon laser carries a reduced risk of complications. In comparison, scatter laser coagulation has an indirect effect. Ischemic retina produces vascular endothelial growth factor (VEGF) which  promotes neovascularization. Scatter laser coagulation destroys this ischemic retina using laser burns thus preventing vitreous hemorrhage, retinal detachment and vision loss. Surgery
Surgical intervention is indicated for severely advanced disease that poses a threat to visual acuity. Indications include longstanding vitreous haemorrhage, vitreous haemorrhage in both eyes, vitreous haemorrhage in patients with only one eye, epiretinal membranes, macular holes and the various forms of retinal detachment. Scleral buckle was a previously popular surgical intervention however, its complications include anterior segment ischemia as a result of vascular occlusion. The vascular occlusion can in turn lead to phthisis bulbi.