Macular choroidal thickness in keratoconus.

CLINICAL RELEVANCE: Expanding practitioner knowledge regarding potential changes in ocular structure of keratoconic eyes will improve the eye care practice and patient management.

BACKGROUND

This study aimed to compare the difference in choroidal thickness between keratoconus patients and two control groups of myopic-astigmatism and emmetropic subjects.

METHODS

A case-control study was undertaken which included 50 patients with keratoconus, 50 with myopic-astigmatism, 30 with emmetropia aged between 18 and 39 years. Choroidal thickness was measured at three different locations, including the subfoveal, nasal, and temporal (750 micrometres) to the fovea, using a spectral-domain optical coherence tomography with an enhanced depth imaging technique.

RESULTS

The mean spherical equivalents were 0.03 ± 0.05, -3.00 ± 0.2, and -3.00 ± 0.3 dioptre in emmetropic, myopic-astigmatism and keratoconus subjects, respectively. The choroid was significantly thicker in keratoconus patients than in myopic-astigmatism and emmetropic subjects in the subfoveal (396 ± 14, 314 ± 12, and 320 ± 18 μm, respectively, p < 0.001), temporal (405 ± 14, 317 ± 12, and 328 ± 19 μm, respectively, p < 0.001) and nasal (376 ± 14, 285 ± 12, and 311 ± 18 μm, respectively; p < 0.001).

CONCLUSION

Choroidal thickness is increased in keratoconus. The exact mechanism for choroidal thickening in individuals with keratoconus is unknown, but inflammatory responses could be the reason.