Myopic Peripapillary Sinkhole: Prolapse of Retinal Nerve Fiber Layer and Posterior Vitreous Into a Sclerochoroidal Hollow Causing Peripapillary Choroidal Thickening and Cavitation

The pathogenesis of peripapillary choroidal thickening and cavitation, a yellow-orange, dome-shaped lesion inferotemporal to the myopic conus, is unknown.^1,2 Some investigators believe the anomaly is congenital in origin owing to the presence of a cleftlike communication between the retina and choroid with vitreous prolapse and anomalous vessels.³ However, we observed a case that developed similar findings but due to a different cause, the gradual sinking of peripapillary retinal tissue into a sclerochoroidal cavity associated with retinal hole formation and posterior vitreous prolapse, newly termed myopic peripapillary sinkhole.

A 63-year-old myopic man was first evaluated in 1984 for pigment dispersion syndrome and suspicious optic discs. Owing to the appearance of the disc and a visual field defect in his left eye, topical antiglaucoma therapy was initiated with betaxolol hydrochloride, 0.25%, twice daily and the intraocular pressure remained between 13 and 16 mm Hg over several decades. Serial disc photographs in the left eye between 1984 (baseline) and 1994 revealed the gradual collapse and ultimate disappearance of a peripapillary retinal vessel associated with an enlarging retinal hole, adjacent disc hemorrhages, and the development of a yellow-orange peripapillary lesion (Figure 1).

Results of a 3-dimensional topographic analysis of the peripapillary tissue (Figure 2) were normal in the right eye. However, the left eye revealed a broad and deep inferotemporal peripapillary depression. Additional views showed collapsed retinal tissue with hole formation and an underlying optically empty space, likely representing vitreous prolapse into a sclerochoroidal cavity (video).

We believe that prior to the development of myopia, the retinal nerve fiber layer is in contact with underlying sclera.⁴ We postulate that as the eye elongates, ectatic sclera pulls away from the overlying retina, creating a hollow or cavern.⁵ The roof of the cavern (the retinal nerve fiber layer) gradually collapses, possibly due to excessive overlying pressure, weakened underlying sclerochoroidal architecture, and/or malnutrition from absence of the choroid in the conus.⁶ As the retinal nerve fiber layer and accompanying vessels collapse (a telltale sign of the sinkhole), axons and retinal nerve fiber layer capillaries kink, with resulting visual field loss, disc hemorrhages, and retinal hole formation. At a crucial point, the retinal hole facilitates the escape of liquid vitreous into the underlying ectatic sclerochoroidal hollow, completing the sinkhole process. We observed 3 other cases of peripapillary thickening and cavitation that manifested in patients older than 55 years. Although we were not able to witness the development of the sinkhole, we suspect that we missed the initial retinal prolapse phase and witnessed only the end of the sinkhole process.

The definition of a sinkhole is a depression in the ground communicating with a subterranean passage and formed by collapse of a cavern roof. Our patient's series of events seems to resemble this natural phenomenon. The entity known as peripapillary thickening and cavitation may be part of a constellation of acquired peripapillary findings as evidenced by the chance long-term observation of a series of events culminating in a finding most accurately described as a myopic peripapillary sinkhole.

Correspondence: Dr Fellman, Glaucoma Associates of Texas, 10740 N Central Expressway, Ste 300, Dallas, TX 75231 (rfellman@glaucomaassociates.com).