OcuLearning › Retina
Sickle Cell Retinopathy (Including Sickle Cell Disease, Anemia, and Trait)
ROUTINE — Retina
Symptoms
- asymptomatic: peripheral lesions are often silent until a complication occurs
- floaters: sudden "cobwebs" or spots usually indicate a vitreous hemorrhage
- flashes & shadows: may signal the onset of a tractional retinal detachment
- systemic: history of painful crises, acute chest syndrome, or joint pain
Clinical Findings
Proliferative (Goldberg staging)
- stage i: peripheral arteriolar occlusions ("silver-wire" vessels)
- stage ii: peripheral a-v anastomoses (loops shunting blood around dead zones)
- stage iii: "sea fan" neovascularization (fan-shaped fronds at the periphery)
- stage iv: vitreous hemorrhage
- stage v: tractional retinal detachment
Non-proliferative signs
- salmon patch: pink-orange superficial hemorrhage (resolves to leave a scar)
- black sunburst: pigmented chorioretinal scar from an old hemorrhage
- comma vessels: sickle-shaped capillaries in the inferior bulbar conjunctiva
- macular thinning: temporal macular thinning often seen on OCT
Etiology
Pathophysiology
- abnormal hb causes rbcs to sickle in the low-oxygen environment of the peripheral retina
- vessel occlusion → ischemia → vegf release → neovascularization ("sea fans")
The SC paradox
- hbsc and hb sβ-thal: have more severe eye disease (higher blood viscosity)
- hbss: has more severe systemic crises but less retinopathy (auto-infarction of vessels)
Red Flags
- sea fans (stage 3): high risk for hemorrhage; requires prophylactic laser
- hyphema + sickle: medical emergency; avoid systemic carbonic anhydrase inhibitors (cais)
- tractional rd: requires advanced surgical intervention by a retina specialist
- sickle trait (hbas) + trauma: can still develop severe retinopathy and high iop
Investigations
Ocular imaging
- widefield fluorescein angiography (fa): the gold standard for staging non-perfusion
- oct: used to detect "the maculopathy of sickle cell" (temporal thinning)
Systemic workup
- hemoglobin electrophoresis: essential to define the specific genotype (SS vs SC)
- cbc and reticulocyte count: to monitor systemic disease activity
Treatment
Proliferative disease
- scatter laser: ablate the ischemic peripheral retina to regress sea fans
- anti-vegf: useful as an adjunct to laser or prior to vitrectomy to reduce bleeding
Surgical
- vitrectomy: indicated for non-clearing vitreous hemorrhage or tractional detachment
Systemic
- hydration and oxygenation: critical during any ocular crisis or surgery
- caution: avoid acetazolamide (diamox) as it promotes sickling via acidosis
Clinical Pearl
Proliferative sickle retinopathy is paradoxically most common in SC, not SS — screen SC patients yearly from age 10, and sector laser arrests sea fans before they bleed.
Differential Diagnosis
- • diabetic retinopathy (central dot-blot hemorrhages vs peripheral sickle fans)
- • sarcoidosis (granulomatous inflammation and "candle-wax" drippings)
- • talc retinopathy (refractile crystals in the macula of iv drug users)
- • fevr (genetic, peripheral non-perfusion in younger patients)