Women aged 40 to 59 years preferred greater under-correction of contact lens power than men of the same age, despite similar near addition requirements, according to a retrospective study published in Clinical Optometry that analyzed habitual contact lens prescriptions in more than 3,000 patients across adulthood.
Study Design and Patient Population
The analysis examined refractive data from 3,082 patients aged 20 to 79 years who attended an eye clinic in Kanagawa, Japan between 2018 and 2024. Investigators compared full refractive correction with the power of contact lenses patients selected for daily use, defining under-correction as the difference between preferred lens power and full correction. Patients were stratified into three age groups: 20 to 39 years, 40 to 59 years, and 60 to 79 years.
The cohort included 2,314 women and 768 men with bilateral phakic eyes and best-corrected distance visual acuity better than 20/30. Ophthalmic testing included autorefractometry, slit-lamp examination, intraocular pressure measurement, funduscopy, visual field testing, optical coherence tomography, and dry eye assessments such as tear break-up time and corneal staining. Near addition power was measured at 30 cm using a standardized chart.
The primary metric was Δ lens power, defined as difference in lens power between preferred corrective power and full refractive correction.
Greater Under-Correction Observed in Women
Sex differences were most pronounced in patients aged 40 to 59 years. In that group, women had greater under-correction than men, with mean Δ lens power of 0.41 diopters in women vs 0.34 diopters in men. Women in the same age group also had slightly lower visual acuity while wearing contact lenses compared with men.
By contrast, near addition requirements were nearly identical between sexes across all age groups. In the 40 to 59 year group, mean near addition was approximately 1.34 diopters in women and 1.35 diopters in men. Progression of near addition with age also followed similar trajectories for both sexes, increasing at approximately 0.08 diopters per year.
Other refractive differences were observed. In the 40 to 59 year group, men had greater astigmatic error and anisometropia than women. Ocular surface parameters were generally worse in women compared with men, except for the Schirmertest.
Factors Associated With Under-Correction
Regression analyses identified different factors associated with under-correction by sex. In women, Δ lens power was associated with myopic spherical equivalent, astigmatic error, anisometropia, near addition power, contact lens power, and visual acuity with contact lenses. In men, under-correction was associated with myopic spherical equivalent, astigmatic error, visual acuity with contact lenses, and tear break-up time. Age was not significantly associated with under-correction ineither sex.
The calculated under-correction (Δ lens power)ranged from 0.41 to 0.27 diopters, depending on sex but not on age. The researchers noted that under-correction is sometimes used to maintain acceptable distance vision while improving near vision during daily activities.
Study Limitations
Study limitations included the retrospective design, recruitment from a single clinic population, and lack of objective measurements of accommodation, lifestyle factors, or working distance that could influence habitual visual demands. The larger number of women compared with men may have introduced detection bias, although the sample size for men remained sufficient for statistical analysis.
The researchers concluded that the current results reveal sex differences in the preferred power of contact lenses to achieve comfortable habitual visual acuity. As they noted, “the magnitude of under-correction was significantly greater in women than men aged 40 to 59 years.”
Disclosures: The researchers reported no conflicts of interest.
Source: Clinical Optometry
