The role of the cornea and lid margins in RGP lens initial comfort

Purpose. To establish the relative importance of the cornea and lid margins in the initial comfort of RGP lenses. Method. The interaction between the lens and either the lid margins or the cornea was manipulated by employing different combinations of RGP and SCL lenses. Five different lens combinations - (a) SCL alone, (b) RGP between two SCLs, (c) SCL underneath RGP, (d) RGP underneath SCL and (e) RGP alone - were worn by each of five subjects in separate trials. Subjective comfort was assessed at fifteen minutes using a 100 point numerical rating scale. Results. The mean comfort levels for each lens combination were a) 97 ± 4, b) 72 ± 16, c) 53 ± 12, d) 52 ± 26 and e) 47 ± 17. For the control eye which did not wear a lens mean comfort was 99 ± 2. No statistically significant differences were found between conditions c), d) and e), however all were significantly different from a), b) and the control. In addition, condition b) differed significantly from both a) and the control. Conclusions. These results suggest that the lid margin is the major factor in determining the initial comfort of RGP lenses.