Rhegmatogenous Retinal Detachment with Horseshoe Tear
medium
eye Ophthalmology
A 62-year-old highly myopic man (myopia −8.5 D) presents with sudden onset of floaters, photopsias, and a progressive superior curtain-like visual field defect in the right eye for 18 hours. Dilated fundus examination reveals a corrugated bullous elevation of the retina in the superotemporal quadrant with loss of choroidal pattern. The structure marked **A** in the diagram shows a U-shaped tear with the flap pointing toward the vitreous base at the equatorial region. Which of the following best describes the PRIMARY PATHOPHYSIOLOGIC MECHANISM that led to the formation of this tear?
A. Spontaneous rupture of a retinal microaneurysm due to chronic hypertension
B. Osmotic swelling of the retina secondary to diabetic macular edema
C. Vitreous traction on the retina following posterior vitreous detachment (PVD), causing a full-thickness retinal break
D. Necrosis of the retinal pigment epithelium from acute central retinal artery occlusion
Explanation
Why "Vitreous traction on the retina following posterior vitreous detachment (PVD), causing a full-thickness retinal break" is right
The horseshoe (flap) tear marked A is the pathognomonic configuration of rhegmatogenous retinal detachment. The U-shaped tear with its flap pointing toward the vitreous base results directly from vitreous traction on adherent vitreoretinal tufts following PVD — the precipitating event in most RRD cases. As liquefied vitreous (synchysis) collapses posteriorly, it exerts dynamic traction on these focal adhesions, creating the full-thickness break that allows liquefied vitreous to dissect into the subretinal space. This mechanism is the cornerstone of RRD pathophysiology and is emphasized in AAO BCSC Retina §11 and Ryan's Retina 6e.
Why each distractor is wrong
Spontaneous rupture of a retinal microaneurysm due to chronic hypertension: Microaneurysm rupture causes retinal hemorrhage and exudative retinal detachment, not a full-thickness break with a characteristic horseshoe flap. Hypertensive retinopathy does not produce the vitreous-traction-mediated tear seen here.
Osmotic swelling of the retina secondary to diabetic macular edema: Diabetic macular edema causes thickening of the retina but does not create a full-thickness break or the U-shaped flap tear. This mechanism is relevant to exudative detachment, not rhegmatogenous detachment.
Necrosis of the retinal pigment epithelium from acute central retinal artery occlusion: CRAO causes inner retinal ischemia and whitening but does not produce a full-thickness retinal break or the characteristic horseshoe tear. The RPE remains intact in CRAO.
High-YieldNEET PG
Horseshoe tear = vitreous traction on vitreoretinal tufts after PVD; flap points toward vitreous base; this is the defining mechanism of RRD.
AAO BCSC Retina §11; Ryan's Retina 6e
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