Background: Choroideremia is an X-linked recessive condition characterized by progressive chorioretinal degeneration. Recently, peculiar scleral ectasias, termed scleral "pits" and "tunnels," have been described as a novel finding in patients with choroideremia, but little is known regarding their etiology or their evolution over time.
Subjects: This is a retrospective chart review of consecutive patients with molecularly-confirmed choroideremia and related female carriers seen at a university-based tertiary referral center from January 2010 to July 2016. Multimodal imaging was evaluated for the evolution of scleral pits on fundus photography and scleral tunnels on optical coherence tomography (OCT). The presence of scleral pits and tunnels was correlated with markers of disease severity including age, visual acuity, and severity of visual field loss.
Results: Thirty patients (21 affected males, 9 female carriers) were included in the study. Scleral pits were seen in 38.1% (8/21) of affected males and found to occur at insertion sites of the posterior ciliary arteries. Those with scleral pits were older, had poorer visual acuity, and more severe visual field loss than those without (p ≤ 0.05). Scleral tunnels were common (68.4%, 13/19 affected males with available OCT imaging), but no statistically-significant associations with disease severity were seen. The development of new scleral pits and tunnels was observed on longitudinal imaging in 4 and 2 affected males, respectively. No scleral pits or tunnels were visualized in any female carriers.
Conclusions: Scleral pits represent degeneration around the posterior ciliary arteries and may be useful as clinical markers of disease severity in choroideremia.