A Rare Case of Bilateral Circumscribed Posterior Keratoconus in Microcornea Associated with Unilateral Irido-Fundal Coloboma

Purpose: To report a rare case of bilateral circumscribed posterior keratoconus in microcornea associated with unilateral irido-fundal coloboma. Method: A case of bilateral circumscribed posterior keratoconus associated with unilateral irido-fundal coloboma presented to us with complaints of diminution of vision in both eyes since birth. The patient had undergone renal transplant for end stage renal disease secondary to chronic glomerulonephritis. Anterior segment examination including anterior segment optical coherence tomography, fundus evaluation and Scheimpflug imaging was done to confirm and document the findings of bilateral posterior keratoconus and irido-fundal coloboma. Results: The diagnosis of bilateral posterior keratoconus was made by typical clinical findings and anterior segment optical coherence tomography. Thinning of posterior curvature of cornea was found on slit lamp examination and was confirmed on anterior segment optical coherence tomography (A/S OCT). Since the thinning was localised, diagnosis of bilateral circumscribed posterior keratoconus was made. Unilateral irido-fundal coloboma was documented on anterior segment and fundus photography. Conclusions: This is the first case report documenting bilateral circumscribed posterior keratoconus along with unilateral irido-fundal coloboma. Further studies are required to look for any association between these two diseases and of these diseases with other ocular as well as systemic anomalies.