An 87-year-old white female was urgently referred to our clinic with complaint of sudden vision loss in her left eye. She noticed the loss upon awakening on the same morning. She was extremely upset and distressed by this event. Her medical history is only remarkable for systemic hypertension for several years otherwise she was in good health. She had cataract surgery in both eyes 12 years earlier. Her BCVA OD was 20/25 and OS 20/400. All other findings were unremarkable, except for well-centered posterior chamber lens implants OU. Her dilated fundus examination revealed signs of very mild hypertensive retinopathy such as arteriosclerosis. The left eye had a dense hemorrhage that covered almost the entire macular area and a notable round lesion along the superotemporal vessels consistent with a retinal arterial microaneurysm (RAM), most likely the origination of the large hemorrhage. (Figure 1)
Figure 1) Fundus photograph of the right eye (A) mild arteriosclerosis and arteriovenous crossing defects. The left eye (B) aneurysmal lesion marked by blue arrow is seen along superotemporal vessels (blue arrow), additionally, a large multi-layer hemorrhage, composed of mainly preretinal component is obscuring the macular view.
Optical coherence tomography (OCT) was instrumental in localizing the macular hemorrhage, showing that the majority of it was in the preretinal and subhyaloid space. (Figure 2)
Without significant evidence of subretinal involvement, a good prognosis could be expected following resolution or removal of the macular hemorrhage. Based on this, following a discussion with the patient and her son in regards to management options and obtaining informed consent, a pars plana vitrectomy (PPV) and internal limiting membrane (ILM) peel was planned and performed on the following day.
Figure 2) Two high-resolution scan orientation of spectral domain (SD) OCT shows a large preretinal hemorrhage (blue arrows) and a second smaller subhyaloid “layered” hemorrhage (yellow arrow). Other than the hypo-reflectivity caused by the dense superficial macular hemorrhage, (orange brackets) no visible subretinal lesion can be detected.
Following an uneventful PPV with ILM peel, on the one-day post-operative visit, the patient indicated well tolerating the day and night of the surgery as well as improved vision. Her visual acuity was 20/25. The fundus exam and OCT showed a remarkable improvement. (Figure 3)
Figure 3) Fundus photograph (A) shows significant resolution of the hemorrhages noted pre-operatively. The RAM is more obvious. OCT Scans (B) also demonstrated the resolution of the preretinal and subhyaloid hemorrhages, the cross-section of the RAM (C) shows the large aneurysmal lesion extending from the inner retina protruding to the retinal surface.
Patient was followed for 3 months with continued improvement, her visual acuity was 20/20 at her last visit at which time she was referred back to her referring optometrist for continued care.
Discussion
Retinal arterial microaneurysm (RAM) is an acquired focal dilation of usually second-order retinal arterioles causing weakening of the affected vascular wall. As the result, they can be exudative or hemorrhagic and are classified as such. RAMs are most commonly found along the temporal, particularly supero-temporal retinal arteries and range from 100 to 250μm. Often these lesions can be present for some time, with no associated symptoms until the patient experiences macular involving hemorrhage or edema. The diagnosis can be easy before the aforementioned complications, however, these lesions can result in extensive multilayer bleeding. (Figure 4) In the presence of chronic leakage and exudates, the findings can mimic diabetic retinopathy or retinal vein occlusion. Other retinal vascular diseases should always be considered in the differential.
Figure 4) Example of multilayer retinal hemorrhage involving sub-, intra- and pre-retinal spaces caused by a RAM seen on fundus photograph and demonstrated on OCT. Image to the right is the same patient one year later. The embolized RAM (blue arrow) is seen along infratemporal vessels. At this stage, the overall fundus appearance can be misinterpreted as other common vascular retinopathies.
Retina imaging such as fundus photography, fluorescein angiography, OCT and OCTA are instrumental in the assessment of these lesions.
The most common etiologic factor for RAM is systemic hypertension as well as other systemic diseases that could alter arterial wall morphology. RAM more commonly affects elderly women.
Primary prevention of RAM is accomplished by management of the systemic contributary factors. There is no clear consensus on the ophthalmic treatment of RAM. Focal photocoagulation can result in embolization of the lesion, reducing either leakage or casual of bleeding. Although post-laser vision loss can occur caused by prograde arterial occlusion. Anti-VEGF injection can improve retinal and macular edema. In the presence of pre-retinal or vitreous hemorrhage, pars plana vitrectomy can be beneficial as demonstrated in the case presented.
The visual prognosis of RAM depends on the extent of macular involvement. Prognosis can be poor with chronic macular edema or with spontaneous hemorrhages involving the subretinal space.
Conclusion
Acquired retinal arterial microaneurysm are among common retinal vascular diseases. In at-risk patients such as the elderly with a history of systemic hypertension, other cardiovascular diseases, and lipid disorders dilated fundus examination and proper imaging can aid detection and appropriate management in advance of a patient returning with associated loss of vision.
