Keratoconus: A One-Sided Debate

Background. A 30-year old man diagnosed with refractive amblyopia OD, was referred for a contact lens fitting. After additional testing was completed the diagnosis was changed to unilateral keratoconus and the patient was successfully fit to a specialty gas permeable lens design OD. Case Report. Presenting symptoms included blurry and double vision with haloes around lights and intermittent tearing, OD. Unaided distance visual acuity (DVA) was 20/100 OD and 20/15 OS. Manifest refraction included a significant degree of myopic astigmatism OD and only a minimal amount OS. While performing biomicroscopy keratoconic signs of prominent corneal nerves and Vogt’s Striae were observed OD only. Keratometric mires were distorted OD and clear OS. Corneal mapping with the Humphrey Atlas Topographer revealed a moderately steep apex OD only with abnormal corneal irregularity (CIM) and shape factor (SF) measurements elicited.OD. On pachymetry the central corneal thickness was measured as 466μm OD and 523μm OS. A light feather touch fluorescein pattern with average edge clearance was seen with the prescribed contact lens OD. After adaptation, the DVA was 20/20- OD with the contact lens compared to 20/15 OS without correction, and a resolution of the patient’s presenting symptoms was reported. Conclusion. Keratoconus is sited as a clinically non-inflammatory corneal ectasia that is typically bilateral and asymmetric. The question of whether monocular keratoconus truly exists is controversial. This case reflects a rare circumstance where only the monitoring of progression will determine whether the initial diagnosis of unilateral keratoconus stands the test of time