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Retinal arterial macroaneurysms (RAMs) are dilated blood vessels that commonly occur in the bifurcations of retinal arteries. While they are usually asymptomatic, RAMs can lead to vision loss if hemorrhaging occurs. In this article, we explore a case where a presumed RAM caused a patient to experience a loss of central vision.
Patient History
A 73-year-old black male visited the University Eye Institute with complaints of a “curtain” or “veil” obstructing his left eye. His left eye’s vision had progressively deteriorated over the past six years. The patient denied any history of headaches, flashes, floaters, ocular trauma, or infections.
The patient had previously been diagnosed with primary open-angle glaucoma, but had discontinued his prescribed medication after one year of use. His last physical exam was about four months prior, during which he reported no chronic or infectious diseases. The patient denied having diabetes, hypertension, cardiovascular disease, cancer, tuberculosis, shortness of breath, and cough. He also mentioned not taking any medications and having no known drug allergies. The patient did not smoke, drink, or use steroids, but he did mention receiving multiple unknown vaccines during a past tour of military duty and extensive travel experience. His family history was negative for diabetes, cardiovascular disease, cancer, and glaucoma.
Diagnostic Data
During the examination, the patient’s blood pressure measured 150/98mm Hg in the left arm while sitting. His visual acuity in the right eye was 20/40 with correction, while the left eye revealed no red reflex due to small pupils and a posterior subcapsular cataract. Other findings included equal-sized pupils, a positive afferent pupillary defect in the left eye, full confrontation fields in the right eye, restricted superonasal fields in the left eye, smooth and unrestricted extraocular muscles in both eyes, and normal intraocular pressure and pachymetry readings.
The posterior segment examination of the left eye showed a white, feathery growth that obscured the macula, along with presumed feeder vessels and a horseshoe-shaped subretinal and preretinal hemorrhage. No retinal breaks or detachments were observed. Pertinent fundus findings in the right eye revealed a large cup-to-disc ratio and no inferior rim, while the left eye showed a smaller cup-to-disc ratio, difficulty assessing due to cataracts, and absence of the inferior rim.
Tentative Diagnosis
Based on the findings, the working diagnosis was an unknown retinal lesion. The patient was referred to a retinal specialist for further evaluation and advised to visit his primary care physician for a physical examination to evaluate possible hypertension.
Follow-Up and Diagnosis
At a one-week follow-up with the retinal specialist, the distance acuity in the right eye improved with correction. However, the left eye exhibited a positive afferent pupillary defect and a vitreous hemorrhage. Fluorescein angiography revealed sharp borders in the area of the subretinal lesion and no choroidal neovascular membrane.
After comprehensive observation and angiography, the final diagnosis was a thrombosed retinal arterial macroaneurysm with subretinal and intraretinal hemorrhages. The patient was scheduled for a follow-up appointment with the retinal clinic in two months.
Further Follow-Up and Treatment
Two months later, the patient was evaluated by another retinal specialist. The specialist confirmed the diagnosis of a RAM, although uncertainty arose due to the inability to detect the focal aneurysm. A review of photos from six years prior revealed the presence of an inferior nasal venous out-pouching close to the left optic nerve, suggesting the possibility of the lesion being a retinal venous macroaneurysm.
A glaucoma evaluation was also initiated, revealing progressive cupping in both eyes. The patient was prescribed Xalatan and Timoptic XE eye drops to manage his glaucoma. The importance of preserving the remaining vision in his right eye was emphasized, along with continued compliance with glaucoma drops and follow-up exams.
In addition to the treatment of the RAM and related ocular sequelae, it is crucial to rule out and treat any underlying systemic conditions. The patient was advised to undergo a full physical examination to investigate possible associated systemic problems. A letter outlining the necessary systemic conditions to be ruled out was sent to his primary care physician.
Discussion
Retinal arterial macroaneurysms are acquired vascular dilations that occur in the first three bifurcations of retinal arteries or at arteriovenous crossings. They are usually asymptomatic but can cause acute vision loss if hemorrhaging occurs. RAMs predominantly affect females over the age of 60 and are commonly associated with systemic hypertension.
The histopathogenesis of RAMs can be linked to physical changes resulting from systemic conditions like hypertension, arteriosclerosis, cardiovascular disease, dyslipidemia, and embolic disease. Damage to the arterial wall, decreased elasticity, and blood turbulence contribute to the development of a RAM. Unlike diabetic retinopathy, where capillaries and small venuoles are affected, macroaneurysms primarily involve arteries.
When managing RAMs, treatment options include laser photocoagulation, vitrectomy, and intravitreal tissue plasminogen activator (t-PA) injections. Laser treatments aim to seal off or cause involution of the RAM, while vitrectomy removes collected blood. Intravitreal t-PA injections can help break down submacular hemorrhages.
In conclusion, RAMs can lead to significant visual deficits but can be managed with prompt diagnosis and appropriate treatment. Close collaboration between optometrists, retinal specialists, and other healthcare professionals is vital to ensure comprehensive care for patients with RAMs.
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