Macular Choroidal Thickening in Keratoconus Patients: Swept-Source Optical Coherence Tomography Study.

Purpose: To determine the choroidal thickness (CT) profile in keratoconus (KC) patients using swept-source optical coherence tomography (SS-OCT).

Methods: This was a prospective, cross-sectional study. One hundred two eyes of 52 KC patients were studied using Pentacam and SS-OCT. The macular CT profile was created by manually measuring the distance between the retinal pigment epithelium and the choroid-sclera junction on horizontal b-scans at nine different macular locations. The results were compared to 93 eyes of 93 healthy controls.

Results: Mean age of the KC group was 34.9 ± 13.5 years and mean axial length (AL) was 24.1 ± 1.3 mm. Mean topographic KC classification (TKC) was 2.0; 39 eyes were classified as early KC (TKC <1-2), 34 eyes as moderate (TKC 2, 2-3), and 29 as advanced (TKC 3+). Mean subfoveal CT was 383.2 μm in KC patients and 280.5 μm in control group ( P < 0.001). CT in KC patients was statistically thicker in all measure locations ( P < 0.001). CT in KC eyes decreased with age, approaching control group at >45 years old, losing statistical significance ( P = 0.37).

Conclusions: CT in KC patients is statistically thicker than in healthy population. After age 45, CT decreases approaching control group values.

Translational Relevance: This study describes changes in the CT profile of KC patients, a disease that was considered purely corneal. These choroidal changes argue that KC is a disease that likely involves several ocular structures other than the cornea, and could open new research lines related to the pathophysiology of KC.