Skill Checkup: A 61-Year-Old Man With Central Visual Acuity Blurring

F. Ryan Prall, MD


September 24, 2021

Figure 1. Exudative (wet) age-related macular degeneration (AMD) is a degenerative disease of the macula lutea, the central area of the retina, where visual acuity is maximal (dark blue). AMD occurs in "dry" or "wet" forms. In the wet form, shown here, new choroidal blood vessels form (neovascularization) and invade the region located under the macula lutea; retinal hemorrhages can occur because these new vessels are very fragile, leading to destruction of the macula lutea.

In the setting of exudative or wet form of AMD, the sine qua non is pathologic choroidal neovascular membranes (CNVM) that develop under the retina. Without treatment, the CNVMs can leak fluid and blood, which may cause a centrally blinding disciform scar. Patients who develop subretinal hemorrhage from CNVM typically report an acute onset, as described in this patient, but others experience insidious blurring due to shallow subretinal fluid or pigment epithelial detachments. Although most cases of AMD are non-neovascular or atrophic, the less common neovascular form of AMD actually causes the majority of severe vision loss associated with the condition.

Aging is the greatest risk factor for AMD, and the condition usually appears in patients 50 years and older. In patients younger than 50, hereditary macular dystrophies should be considered. Other risk factors include northern European ancestry and genetics, with smoking shown to be a major modifiable risk factor. Some patients with AMD are asymptomatic with the condition diagnosed incidentally, but others may notice mild symptoms, including minimally blurred central visual acuity, contrast and color disturbances, and metamorphopsia. If geographic atrophy develops in the macular region, patients may notice a scotoma, which can enlarge over months to years. Ultimately, exudative AMD usually culminates with a stable central scotoma, and visual acuity falls below the reading level and the legal driving level.


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