A Randomized Trial to Evaluate the Effect of Toric Versus Spherical Contact Lenses on Vision and Eyestrain

Abstract

Objectives:To compare the effect of toric versus spherical soft contact lenses on objective measures of visual performance using visual acuity and electromyography of the orbicularis oculi muscle.Methods:Current soft contact lens wearers with −0.75 to −1.75 D astigmatism in each eye were binocularly fitted with toric (1-Day ACUVUE MOIST for astigmatism) and spherical (1-Day ACUVUE MOIST) contact lenses in random order. After each fitting and at 1-week follow-up, high- and low-contrast visual acuities were measured. Electromyography was used to objectively evaluate eyestrain. Linear mixed models were used to assess differences between toric and spherical contact lenses.Results:The mean age (±SD) of the 60 participants was 27.5±5.0 years, spherical refractive error was −3.68±2.01 D, and cylinder was −1.28±0.36 D. High- and low-contrast visual acuities with toric lenses were better than with spherical lenses at both fitting (toric high-contrast: −0.065±0.078 and low-contrast: 0.133±0.103 vs. spherical high-contrast: 0.001±0.104 and low-contrast: 0.224±0.107) and follow-up (toric high-contrast: −0.083±0.087 and low-contrast: 0.108±0.107 vs. spherical high-contrast: −0.015±0.095 and low-contrast: 0.211±0.104) (all P<0.0001). Electromyography-measured eyestrain was less with toric versus spherical contact lenses at fitting (least-square ratio of toric over spherical=0.72; P=0.0019) but not at follow-up (ratio=0.86; P=0.11).Conclusion:These results suggest that toric contact lenses provided improved objective measures of vision in a low-to-moderate astigmatic population.

Optical Quality and Visual Performance With Different Toric Contact Lens Designs

“…Several recent studies have reported the benefit of correcting low amounts of astigmatism in comparing distance vision and near visual performance with digital devices or night-time driving performance. [30][31][32][33][34] According to a recent systematic literature review on the epidemiology and burden of astigmatism, 35 uncorrected astigmatism decreases the vision-related quality of life and work productivity, in addition to posing an economic burden on patients. Based on these results, a proactive prescription of toric CLs for eyes with astigmatism is recommended because improved visual performance and more patient satisfaction are expected when astigmatism is corrected properly.…”

Associations between Binocular Vision Disorders and Contact Lens Dissatisfaction

“…In those with low to moderate amounts of astigmatism, toric CLs improve visual acuity, [206][207][208] subjective vision, 16 visual symptoms, 16 eyestrain, 207 and satisfaction 16 compared to spherical CLs. While prescribing spherical CLs to those with significant astigmatism may have been a source of vision problems in the past, 209 it does not appear to be a current source.…”

“…Correcting low to moderate amounts of astigmatism with toric CLs can improve subjective vision, 16 visual symptoms, 16 and eyestrain, 207 compared to correction with spherical CLs. All participants in the current study wore spherical CLs, including those with up to 1.00 D of astigmatism, suggesting uncorrected astigmatism may have been a…”

Clinical Investigation of Flat Pack Toric Contact Lenses and Wearer Attitudes to Environmental Impact

“…4 This is beneficial to patients as studies indicate improved visual acuity and contrast sensitivity when fitted with toric contact lenses. [5][6][7] More recently, a study comparing subjective and objective measures of visual performance with digital devices in astigmatic patients trialing toric and spherical lenses of the same material found that participants preferred the comfort and vision with the toric contact lenses. 8 Dumbleton et al 9 investigated contact lens drop out in a retrospective sample of over 4,000 lapsed wearers, and while discomfort was cited as the most common cause, poor vision and issues with lens handling were also common causes of lens discontinuation.…”

“… 4 This is beneficial to patients as studies indicate improved visual acuity and contrast sensitivity when fitted with toric contact lenses. 5 – 7 More recently, a study comparing subjective and objective measures of visual performance with digital devices in astigmatic patients trialing toric and spherical lenses of the same material found that participants preferred the comfort and vision with the toric contact lenses. 8 …”