Patrick J. Caroline and Mark P. Andre first reported about soft lens orthokeratology in 2005. In a number of articles in the past five years, they reported about their research on this topic and their new findings. The aim of this study was to continue the research of Patrick J. Caroline and Mark P. Andre and to collect more information about the outcome of the technique.
Ten subjects with low myopia from -0.25 D to -1.25 D and a refractive astigmatism from plano to -0.75 D were fitted with a -10.00 D CIBA VISION AIR OPTIX® NIGHT&DAY® silicone hydrogel contact lens and were told to wear the lenses over night and everted. Corneal topography and refraction measurements were taken after one night, one week and one month of contact lens wear.
Eight out of ten subjects finished the study, six female and two male. The mean age of the subjects was 23.9 years. With the eight subjects who finished the study, the mean change in subjective refraction was about +1.00 D in the sphere and +0.22 D in the cylinder, with maximum changes of +1.75 D sphere and +0.75 D cylinder. The mean apical power change, measured with the topographer, was 1.11 D. Changes in K - readings ranged from slight corneal steepening in both of the meridians to 0.23 mm of corneal flattening in the horizontal meridian and 0.27 mm of corneal flattening in the vertical meridian. Corneal eccentricity decreased about 0.65 on average. The main complaints and problems were the high minus power and the decentration of the contact lens and the occurrence of ghosting at night.
The results of this study show that everted wear of a high minus silicone hydrogel contact lens can lead to orthokeratology - such as changes in corneal topography and subjective refraction. These changes range from plano to +1.75 D sphere and +0.25 D to +0.75 D cylinder but are unpredictable and vary from subject to subject. Additional studies regarding the contact lens decentration and the unpredictability of the outcome need to be done to optimize the process.