Clinical performance of polynomial lenses versus tri-curve lenses. II: ocular responses.
This study, which was a continuation of the previous one, aimed to determine the subjective and objective responses after wearing polynomial and tri-curve rigid gas permeable (RGP) lenses over a period of 6 months. Subjects were divided into two groups, each of which wore either one of these lens designs and 17 of 22 subjects completed the 6-month study. Subjective responses were assessed by a questionnaire while the objective responses including vision, contrast sensitivity, lens fitting and the corneal integrity, corneal thickness and endothelial cell morphology were assessed by the examiner. There were no significant differences in the subjective ratings, vision, contrast sensitivity and the lens fitting between the two groups. Except for the p-value (p) and the apical radius (r(o)) along the steepest meridian and the coefficient of variation in cell size in the inferior corneal endothelium, there were no significant changes in the palpebral aperture size, the p-value and r(o) along the flattest meridian, corneal thickness and the other endothelial cell variables after the 6-month study period. The poor success and high dropout rates of RGP lens wear in this study stress the importance and need for further investigations of such lenses.
Cheung
S W
SW
Department of Optometry and Radiography, The Hong Kong Polytechnic University, Kowloon, SAR, China. orpeggy@polyu.edu.hk
Cho
P
P
Douthwaite
W
W