Clinical biomicroscopy and retinoscopy findings of keratoconus in a Middle Eastern population

Abstract

Background: The present work was conducted to investigate the prevalence of clinical biomicroscopy and retinoscopy findings of corneas with keratoconus (KC) at first presentation and their relationship with disease severity. Method: In a prospective cross-sectional study, 371 consecutive KC patients were examined by slitlamp biomicroscopy and retinoscopy at the time of diagnosis. This research evaluates the prevalence of clinical findings such as a corneal protrusion, Vogt's striae, Fleischer's ring, Munson's sign, Rizzuti's sign, corneal scars, as well as any additional KC signs such as prominent nerve fibres, scissoring reflex and Charleaux ‘oil droplet’ sign on retinoscopy. Keratometry (mean K), central and thinnest corneal thickness (CCT and TCT), anterior and posterior elevation (AE and PE), and astigmatism by means of Pentacam, and visual acuity (VA) were recorded for each patient. The severity of KC was graded on the basis of the Keratoconus Severity Score. Results: Corneal protrusion, scissoring reflex, corneal thinning, Fleischer's ring, and prominent nerve fibres were the most prevalent findings in the keratoconic corneas (71.7 per cent, 64.2 per cent, 56.6 per cent, 55.5 per cent and 54.7 per cent, respectively). Those KC patients with these clinical findings had significantly higher mean K, AE and PE, while having significantly lower CCT, TCT and VA compared to those who did not present these signs (p < 0.05). The presence of clinical findings was associated with more severe disease (p < 0.001, all comparisons). Wearing contact lenses was associated with the increase in the risk of corneal scarring (p = 0.009, odds ratio = 1.761, 95 per cent confidence interval = 1.126 to 2.755). Conclusion: This study provided information regarding the presence of the clinical slitlamp biomicroscopic and retinoscopic findings with severity of KC. A positive association was found between the presence of clinical signs and topographic parameters. In addition, wearing contact lenses was associated with the increase in the risk of corneal scarring.