Introduction and epidemiology
Classification of retinopathy
Hemoglobin mutations and structural changes
Name | Genetics | Systemicmanifestations | PSR prevalence (Fekrat and Goldberg [7]) | PSR prevalence (Dembélé et al. [8]) | PSR prevalence (Bonanomi et al. [9]) | PSR prevalence (Leveziel et al. [10]) | PSR prevalence (Downes et al. [11]) | |
---|---|---|---|---|---|---|---|---|
HbSS | Sickle cell anemia | Sickle cell homozygote | Most severe systemically | 3% | 5.2% | 14.64% | 18.1% | 14% |
HbSC | Sickle cell “C” trait | Sickle cell heterozygote, with another abnormal HbC allele | Mild systemically | 33% | 12.4% | 54.54% | 54.6% | 43% |
HbSThal | β-Thalassaemia anemia | Sickle cell heterozygote, with another β-thalassaemia allele | Severe form systemically (βo) Milder form systemically (β+) | 14% | 9.4% (Sβ° thalassemia) 9.3% (Sβ+-thalassemia) | – | – | – |
HbSD, HbSE, HbSO | Sickle cell heterozygote, with another abnormal Hb allele | Varies systemically | – | – | – | – | – | |
HbAS | Sickle cell trait | Sickle cell heterozygote, with 1 normal Hb allele | Mild systemically | – | – | – | – |
Non-proliferative sickle cell retinopathy (stages I–II)
Proliferative sickle cell retinopathy (stages III–V)
Orbital manifestations of SCD
Glaucoma
Genetic and systemic risk factors of sickle cell retinopathy and proliferative sickle cell retinopathy
Diagnosis
Differential diagnoses
Differential diagnoses | |
---|---|
Macular ischemia/infarction | Diabetic retinopathy Retinal vascular occlusion, e.g., posterior ciliary artery thrombosis Retinal embolization, e.g., talc retinopathy, internal carotid artery embolism Infectious retinopathy, e.g., toxoplasmosis, dengue (Yip et al. [40]). |
Ischemic vascular disease | Proliferative diabetic retinopathy Central/branch retinal vein occlusion Ocular ischemic syndrome Radiation retinopathy Retinopathy of prematurity Familial exudative vitreoretinopathy Eales’ disease Blood dyscrasias, e.g., chronic myeloid leukemia, deficiency of protein C, or protein S |
Ischemic inflammatory disease | Sarcoidosis Retinal vasculitis Intermediate uveitis Acute retinal necrosis |
Miscellaneous | Incontinentia pigmenti. Vascular occlusive phenomena of small vessels causing avascular peripheral retina and peripheral neovascularization. Autosomal dominant vitreoretinochoroidopathy. Associated vascular abnormalities, e.g., microaneurysms, vascular leakage, arteriolar attenuation, venous beading, venous sheathing, venous occlusion, focal venous staining, and retinal neovascularisation Chronic rhegmatogenous retinal detachment with macrocyst formation, peripheral capillary non-perfusion, telangiectasias, and retinal neovascularization. Neovascularization posterior to the retinal holes (Bonnet [41]), which could have a seafan configuration (Georgalas et al. [42]). Non-rhegmatogenous retinal detachment with secondary neovascularization, e.g., Coats disease, peripheral retinoschisis (Pearson and Jagger [43]). Scleral buckle. A tight encirclage may impair the long posterior ciliary arteries and choroidal venous drainage (Duguid et al. [44]). Retinitis pigmentosa (Kadayifcilar et al. [45]). |