Spectacle prescriptions review to determine prevalence of ametropia and coverage of frequent replacement soft toric contact lenses
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PURPOSE: To determine the prevalence of ametropia and astigmatism in a clinic population and to estimate the coverage of frequent replacement soft toric lenses. METHODS: A review of patient files was conducted at three clinical sites. Prescription data collected between January 2014 and March 2017 in a patient cohort 14 to 70 years of age inclusive were analyzed to determine prevalence of ametropia and astigmatism. The percent coverage of frequent replacement soft toric contact lenses has further been estimated using different ranges for sphere, cylinder and axis availability. RESULTS: In total 101,973 patients were included in the analysis of which 69.5% were considered myopic, 26.9% hyperopic and 3.5% emmetropic as determined by the eye with the larger absolute value of the spherical equivalent refraction. Astigmatism in at least one eye was found in 87.2% of the population, with 37.0% of the patients exhibiting astigmatism of at least -1.00DC in at least one eye. With-the-rule astigmatism was most prevalent in the 14 to 20 year-olds (53.0%), while against-the-rule astigmatism was most prevalent in the 41 to 70 year-olds (50.7%). For astigmatic eyes with a cylinder of at least -0.75DC (n = 83,540; 41% of all eyes), the coverage with toric soft lenses varied greatly depending on parameter availability and ranged between 30.7% (sphere: Plano to -3.00D, cylinder: up to -1.75DC, axes: 90 ± 10° and 180 ± 10°) and 96.4% (sphere: + 6.00D to -10.00D, cylinders: up to -2.75DC, 18 axes). CONCLUSION: Currently available frequent replacement soft toric contact lenses provide coverage for up to 96.4% of potential patients.
