Abstract :
Keratometry is the measurement of anterior surface of corneal curvature in its steepest and flattest axis by various methods. There are many advances in measurement of keratometric values. Corneal topography and Modern videokeratoscopes provide an accurate representation of the anterior corneal surface to allow assessment of corneal irregularities in keratoconus, pellucid marginal degeneration, preoperative cataract
workup - IOL calculation/TORIC lens implantation, refractive surgery preoperative assessment and post-op evaluation, evaluating pathologies like coneal dystrophies, scars, pterigium, recurrent erosions and contact lens fitting and evaluating the corneal contribution to optical aberrations of the whole eye Astigmatism (more than 0.5 diopters) is a commonly encountered refractive error, accounting for about aprx. 13-40 per
cent of the refractive errors of the human eye according to various studies. In our study, 200 eyes of patients were studied over period of 2 year, with autorefractometer which measures total astigmatism (corneal and lenticular) and Bausch and Lomb manual keratometer and oculus topographer which measures anterior corneal astigmatism and results were compared. In our study 92.5% of eyes had regular astigmatism
while 7.5% of eyes had irregular astigmatism. Various causes of corneal astigmatism were pterygium, keratoconus, PMCD, corneal degeneration, corneal opacity in that order. No significant clinical cause was found in 74.5% of eyes. Maximum repeatability was found with oculus topographer followed by autorefractometer and Bausch and Lomb manual keratometer.
Keyword :
Keratometer, Pterygium.