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Update your Knowledge with MKSAP 17 Q&A: Answer and Critique

Answer

D: Retinal detachment

Educational Objective

Diagnose retinal detachment.

Critique

This patient most likely has retinal detachment. Retinal detachment, which occurs mainly in patients with myopia, results when the neurosensory layer of the retina separates from the retinal pigment epithelial layer and choroid. The characteristic features of retinal detachment are floaters, flashes of light (photopsias), and squiggly lines, followed by a sudden, peripheral visual field defect that resembles a black curtain and progresses across the entire visual field. The most common type of retinal detachment is posterior vitreous detachment (PVD), which typically occurs in persons aged 50 to 75 years. Symptoms usually progress over a period of 1 week to 3 months and can lead to blindness. Patients with retinal detachment should be urgently evaluated by an ophthalmologist.

Age-related macular degeneration (AMD) is a leading cause of blindness in older patients. In dry AMD, extracellular material (drusen) is deposited in the macular region of one or both eyes. Patients often report a gradual loss of vision. In wet AMD, patients with pre-existing dry AMD will progress to develop new vessel growth under the retina. Bleeding and exudation from these vessels result in sudden (or rapid onset over weeks), painless blurring or warping of central vision. Wet AMD results in severe vision loss. This patient's peripheral vision loss and the presence of floaters and photopsias are not consistent with AMD.

Patients with branch retinal vein occlusion, which is caused by arterial compression of the retinal vein, are typically asymptomatic. Funduscopic examination may reveal an afferent pupillary defect, congested retinal veins, scattered retinal hemorrhages, and cotton wool spots in the region of occlusion, which are not present in this patient.

Central retinal artery occlusion (CRAO) is caused by vasospasm or emboli. Patients with CRAO are usually elderly and present with profound and sudden vision loss. Findings on funduscopic examination include afferent pupillary defect and cherry red fovea that is accentuated by a pale retinal background, both of which are absent in this patient.

Key Point

Retinal detachment, which occurs mainly in patients with myopia, is characterized by floaters, photopsias, and squiggly lines, followed by a sudden, peripheral visual field defect that resembles a black curtain and progresses across the peripheral field of vision.

Bibliogrpahy

Lee E, Dogramaci M, Williamson T. Displacement of the retina. Ophthalmology. 2012 Jan;119(1):206.e1; author reply 206-7. [PMID: 22214956]

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