OcuLearning › Retina
Retinal Arterial Macroaneurysm
ROUTINE — Retina
Symptoms
- sudden vision loss: typically due to acute hemorrhage (vitreous or macular)
- gradual blurring: caused by chronic exudation and macular edema
- floaters: if blood breaks through into the vitreous cavity
- systemics: almost universally associated with hypertension
Clinical Findings
Demographics & location
- classic profile: elderly women (70s–80s) with chronic hypertension
- anatomy: saccular dilation of a major retinal artery within the first 3 bifurcations
- superotemporal arcade is the most common site (highest pressure/flow)
Multi-level hemorrhage (near-pathognomonic)
- blood in ≥3 levels: subretinal, intraretinal, and pre-retinal (sub-hyaloid)
- the hemorrhage is centered at an arterial bifurcation or A/V crossing
Exudative pattern
- "circinate" ring of hard exudates surrounding the aneurysm
- chronic macular edema mimicking diabetic retinopathy
Natural history
- most RAMs spontaneously thrombose, fibrose, and involute after a bleeding event
Etiology
Pathophysiology
- mechanical shear stress weakens the arterial wall at points of turbulence
- atherosclerosis and chronic hypertension are the primary drivers
- ~30% of cases have a concurrent retinal vein obstruction
Red Flags
- multi-level hemorrhage centered on an artery: suggests RAM over other pathologies
- subfoveal hemorrhage: high risk of permanent photoreceptor toxicity; requires displacement
- multiple macroaneurysms: indicates severely uncontrolled systemic hypertension
- premacular sub-hyaloid hemorrhage: can be drained with YAG to speed recovery
Investigations
Ocular exam
- dilated exam looking for the "light bulb" arterial dilation and circinate exudates
Imaging
- OCT: essential for tracking macular edema and subretinal blood volume
- ICG Angiography: superior to FA for seeing the RAM through overlying blood
- IVFA: shows focal hyperfluorescence (the aneurysm) with late leakage
Systemic workup
- mandatory blood pressure check and referral to PCP for cardiovascular management
Treatment
Medical & surgical
- observation: for the majority of cases as they tend to self-thrombose
- anti-VEGF: effective for associated macular edema
- focal laser: gentle argon/yellow laser to the aneurysm; avoid the feeding artery
- displacement: intravitreal gas injection to move blood away from the fovea
- vitrectomy: for dense vitreous hemorrhage or thick sub-ILM macular blood
Systemic
- primary care coordination for aggressive hypertension and lipid control
Clinical Pearl
Most macroaneurysms self-thrombose and need no treatment — the exception is submacular hemorrhage, where pneumatic displacement with tPA can rescue central vision.
Differential Diagnosis
- • valsalva retinopathy (similar multi-level blood, but no aneurysm)
- • diabetic retinopathy (microaneurysms are smaller and venous-side)
- • coats disease (massive exudation in young males)
- • exudative amd (associated with drusen and subretinal neovascularization)