Table 1.

Initial parameters of the refractive corrections.

	Radius of curvature, mm	Conic constant	Refractive index	Distance, mm
Spectacles
Anterior surface	(Variable)	–(1/ncorr) (Zadnik, Barr, & Edrington, 1998)	1.510	2.000
Posterior surface	100	–(ncorr/nair) (Zadnik, Barr, & Edrington, 1998)	1.000	12.000
Scleral lenses
Anterior surface	(Variable)	–(1/ncorr) (Zadnik, Barr, & Edrington, 1998)	1.415	0.300
Posterior surface	7.20	–(ncorr/ntears) (Zadnik, Barr, & Edrington, 1998)	1.3368 (Patel, Boyd, & Burns, 2000)	0.325

n_corr = refractive index of corrective lens; n_tears = refractive index of tear fluid; n_air = refractive index of air.