Just how common is astigmatism in ametropes, and how many eyeglass wearers could be using toric lenses to correct it? That’s what a team of Canadian researchers recently investigated.
The study evaluated the prescription data of 101,973 spectacle lens wearers ages 14 to 70 to determine the prevalence of various refractive errors. The team then estimated the coverage percentage of frequent replacement soft toric contact lenses using different ranges for sphere, cylinder and axis availability.
Of the total patients, the researchers found that 69.5% were myopic, 26.9% were hyperopic and 3.5% were emmetropic. Within the population, 87.2% had astigmatism in at least one eye, with 37% exhibiting astigmatism of at least -1.00DC in at least one eye. The team notes that with-the-rule astigmatism was most prevalent in patients who were 14 to 20 years old (53%) while against-the-rule astigmatism was most prevalent in those ages 41 to 70 (50.7%).
For astigmatic eyes with a cylinder of at least -0.75DC (41%), they add that the coverage with toric soft lenses varied greatly, ranging from 30.7% to 96.4%, depending on parameter availability.
|Luensmann D, Schaeffer JL, Rumney NJ, et al. Spectacle prescriptions review to determine prevalence of ametropia and coverage of frequent replacement soft toric contact lenses. Cont Lens Anterior Eye. 2018;41(5):412-20.|