Analysis of corneal topography in patients with pure microphthalmia in Eastern China

Objectives: To determine the typical corneal changes in pure microphthalmia using a corneal topography system and identify characteristics that may assist in early diagnosis. Methods: Patients with pure microphthalmia and healthy control subjects underwent corneal topography analysis (Orbscan IIZ Corneal Topography System; Bausch and Lomb, Bridgewater, NJ, USA) to determine degree of corneal astigmatism (mean A), simulation of corneal astigmatism (sim A), mean keratometry (mean K), simulated keratometry (sim K), irregularities in the 3 - and 5mm zone, and mean thickness of nine distinct corneal regions. Results: Patients with pure microphthalmia (n ¼ 12) had significantly higher mean K, sim K, mean A, sim A, 3.0 mm irregularity and 5.0 mm irregularity, and exhibited significantly more false keratoconus than controls (n ¼ 12). There was a significant between-group difference in the morphology of the anterior corneal surface and the central curvature of the cornea. Conclusions: Changes in corneal morphology observed in this study could be useful in borderline situations to confirm the diagnosis of pure microphthalmia.