Macular thicknesses in patients with keratoconus: An optical coherence tomography study

Abstract

Background: Keratoconus, a corneal ectasia associated with thickness and structural changes, has been reported to co-exist with posterior segment ocular conditions. However, very few studies have reported on macular thicknesses in individuals with keratoconus. Aim: The aim of this study was to investigate macular thicknesses in participants with keratoconus. Setting: This study was conducted at the University of KwaZulu-Natal (UKZN). Methods: A comparative cross-sectional research design was used. The sample consisted of 88 participants with 44 each in the control and keratoconus (15, 11 and 18 with mild, moderate and severe keratoconus, respectively) groups. Macular thicknesses were obtained with the Fourierdomain Optovue iVue100 optical coherence tomographer using the nine Early Treatment Diabetic Retinopathy Study sectors. Data were analysed using descriptive and inferential statistics. Results: Overall, the mean macular thicknesses were comparable among the control and three keratoconus groups (p ≥ 0.199). The mean central foveal thickness was greater in the severe keratoconus group (259 μm) than the other three study groups that showed similar measurements (247 μm-248 μm). The central fovea was thinnest followed by the perifovea and parafovea in all four study groups. The mean thickness in the nasal and temporal quadrants of the parafovea and perifovea was thickest and thinnest, respectively, in all four study groups. Conclusion: Macular thicknesses via optical coherence tomography in individuals with keratoconus and controls are similar with thickness differences that are clinically insignificant. Consequently, macular thicknesses should be included in the preoperative assessment of individuals with keratoconus awaiting corneal transplantation to assess the integrity of the retina prior to surgery.