The Evolution of Diagnostics for Keratoconus: From Ophthalmometry to Biomechanics
Akhil Bevara, Pravin K. Vaddavalli
Abstract
PURPOSE: To enumerate the various diagnostic modalities used for keratoconus and their evolution over the past century. METHODS: A comprehensive literature search including articles on diagnosis on keratoconus were searched on PUBMED and summarized in this review. RESULTS: Initially diagnosed in later stages of the disease process through clinical signs and retinoscopy, the initial introduction of corneal topography devices like Placido disc, photokeratoscopy, keratometry and computer-assisted videokeratography helped in the earlier detection of keratoconus. The evolution of corneal tomography, initially with slit scanning devices and later with Scheimpflug imaging, has vastly improved the accuracy and detection of clinical and sub-clinical disease. Analyzing the alteration in corneal biomechanics further contributed to the earlier detection of keratoconus even before the tomographic changes became evident. Anterior segment optical coherence tomography has proven to be a helpful adjuvant in diagnosing keratoconus, especially with epithelial thickness mapping. Confocal microscopy has helped us understand the alterations at a cellular level in keratoconic corneas. CONCLUSION: Thus, the collective contribution of the various investigative modalities have greatly enhanced earlier and accurate detection of keratoconus, thus reducing the disease morbidity.