Choroidal Caverns: A Novel Optical Coherence Tomography Finding in Geographic Atrophy

Abstract

Purpose: To describe and interpret "choroidal caverns," an unreported optical coherence tomography (OCT) finding in the choroid of patients with geographic atrophy (GA) secondary to atrophic AMD.

Methods: Retrospective analysis of patients with GA. Main outcomes measures included estimation of the prevalence of choroidal caverns, their localization and relation with retinal-choroidal structures by reviewing medical records and multimodal imaging.

Results: One hundred twenty consecutive patients (mean age 80.5 ± 8.61 years) were included. Among the 201 eyes with GA, 17 eyes of 15 patients presented choroidal caverns on OCT B-scan in GA areas (a total of 43 choroidal caverns, mean 2.5/eye, variably localized in the Sattler and Haller layers, with relative preservation of the choriocapillaris). This accounts for 12.5% estimated prevalence (6.5-18.5, 95% confidence interval [CI]) of choroidal caverns in GA areas of atrophic AMD patients. Choroidal caverns appeared on OCT (both B-scan and en face) as gaping hyporeflective cavities in the choroid, typically empty, angular, without hyperreflective borders, often with punctate/linear hyperreflectivities internally. Indocyanine angiography and OCT-Angiography confirmed that the areas occupied by these cavities do not represent perfused choroidal blood vessels.

Conclusions: Choroidal caverns represent a relatively infrequent peculiar finding in GA areas of atrophic AMD eyes. They appear as gaping angular hyporeflective cavities in areas devoid of choroidal vessels, often with punctate/linear hyperreflectivities internally. Choroidal caverns may possibly arise from nonperfused ghost vessels and persistence of stromal pillars where the vessels were originally situated.

Figure 1

MultiColor imaging, ICGA en face optical coherence tomography (OCT), and B-scan OCT of choroidal caverns. MultiColor imaging (A) shows refractile intense hyperreflective material in correspondence of the choroidal caverns (dotted circles). Indocyanine green angiography (B) and en face OCT (C) of choroidal caverns (asterisk) reveals that the areas occupied by these cavities are devoid of significant blood flow (arrowheads). Optical coherence tomography B-scan (D) shows the choroidal caverns as gaping hyporeflective cavities in the choroid (both Sattler and Haller layers, with relative preservation of the choriocapillaris), well distinguishable from choroidal vessels, which are slightly hyperreflective due to the presence of blood, with characteristic hyperreflective border due to the vessel wall (arrow). The cavities in choroidal caverns are typically empty, angular, with punctate hyperreflectivities internally (asterisk).

Figure 2

Optical coherence tomography angiography (OCT-A), and en face and simultaneous B-scan OCT in the right eye of a patient with multiple choroidal caverns. Optical coherence tomography angiography (A) and en face OCT (B) show choroidal caverns as cavities devoid of significant blood flow (arrowheads and dotted circles). Note the choroidal caverns localized at different levels within the choroid layers.

Figure 3

Simultaneous infrared reflectance and B-scan OCT in the left eye of patient with multiple choroidal caverns. Optical coherence tomography B-scan reveals multiple choroidal caverns as gaping hyporeflective angular cavities in the choroid (Sattler and Haller layers, with relative preservation of both the choriocapillaris) with punctate/linear hyperreflectivities internally (enlarged view).