Study To Analyse The Causes Of Misdiagnosis Of Keratoconus In Patient Referred To Tertiary Care Centre In India

To determine the factors leading to clinical and topographic misdiagnosis of Keratoconus in patients referred to a tertiary care centre.

Retrospective analysis of records of 560 patients who were referred with a presumed diagnosis of keratoconus between January 2023 and Aug 2024 to our teriary care center in India 

We retrospectively reviewed 560 patients presenting to our tertiary care centre in India with a presumed diagnosis of keratoconus. Slit lamp examination, refraction and corneal topography was done and patients having true keratoconus were excluded. Patients misdiagnosed as keratoconus were included and the factors contributing to the misdiagnosis were analysed.

Of the 560 patients , 217 eyes were misdiagnosed as keratoconus. 10 eyes were finally diagnosed with PMCD (Pellucid Marginal Corneal degeneration) and 8 eyes with ectasia following refractive surgery. The mean age of patients was 18.4 years (6 - 65 years). 123 eyes had amblyopia secondary to high astigmatism, 9 eyes had corneal scar, 2 eyes had PPCD (Posterior Polymorphous corneal degeneration), 1 eye had FECD (Fuchs endothelial corneal Dystrophy). Among the topographic findings 19 eyes had small horizontal White-to-white (HWTW) showing pseudoectasia on Belin-Ambrosio ectasia (BAD) display and 6 eyes had thin pachymetry with no other signs of ectasia.

Compound myopic astigmatism was the commonest condition misdiagnosed as keratoconus in our cohort. Other causes included thin cornea, PPCD, FECD and corneal scars. Small HWTW, Keratometric values and corneal thickness may contribute to the misdiagnosis of KC.