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Digital Visual Acuity and Reading Performance with Positive and Negative Display Polarities After Bilateral
Thanapong Somkijrungroj1, Nuntachai Surawatsatien1, Waraluck Supawatjariyakul2
1Center of Excellence in Retina, Department of Ophthalmology, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, The Thai Red Cross Society, Bangkok, Thailand.
Introduction:
Traditional acuity charts may not fully capture visual performance during everyday digital device use. Digital screen-based assessments may better reflect contemporary visual demands, and display polarity may influence reading performance in patients with multifocal intraocular lenses (MF-IOLs). Furthermore, display polarities differ in luminance and contrast characteristics, which may influence pupil size and reading performance in patients with MF-IOLs. We aimed to compare digital visual acuity (VA) between positive (black-on-white) and negative (white-on-black) display polarities and evaluated reading speed and critical print size (CPS) in patients with bilateral diffractive MF-IOLs.
Methods:
In this non-randomized, observational study, consecutive participants who underwent bilateral diffractive MF-IOL (AcrySof IQ PanOptix) implantation with repeated assessments at postoperative day 1, week 1, month 1, and month 3. Monocular and binocular uncorrected and corrected distance, intermediate, and near VA were assessed using a Snellen chart and MNREAD application on an iPad. Reading acuity between display polarities was compared using paired t-tests, while reading speed and CPS were assessed using the positive display polarity.
Results:
Twenty-six participants completed the study. At 3 months, uncorrected distance VA was -0.084 ± 0.079 logMAR. Digital VA at 60 cm and 40 cm was -0.115 ± 0.104 and -0.008 ± 0.084 logMAR, respectively. Reading performance did not differ significantly between positive and negative display polarities at 60 cm (p = 0.055). Mean CPS was 0.173 ± 0.0168 logMAR at 1 month and 0.238 ± 0.100 logMAR at 3 months. Mean reading speed was 84.63 ± 27.46 WPM at 1 month and 101.89 ± 72.62 WPM at 3 months (p = 0.133).
Conclusions:
Bilateral diffractive MF-IOLs provided favorable digital and conventional visual outcomes with small differences observed and were not considered clinically meaningful. Digital reading assessments provided complementary functional information, including reading speed and critical print size, without replacing conventional VA assessment.
