Abstract
Purpose :
To determine the vertical position of single-vision (SV) and progressive power lens (PPL) region-of-use during computer task at two distances, assessing lens usage variations based on required addition (Add)
Methods :
The pupil position of 15 subjects classified into three groups (G1, 5 non-presbyopic subjects; G2, 5 subjects with Add≤2D; G3, 5 subjects with Add>2D) was recorded with an Eye-Tracker (ET, Tobii Pro Glasses 3, Sweden; sampling frequency 50Hz) while searching a specific location on a map (20 trials) displayed on a TV (70cm; 32.8x53.2deg) and a laptop (PC, 65cm; 15.3x27deg). Two randomly ordered conditions were performed: wearing a SV (Endless Single-Vision, IOT) and wearing a PPL (Essential Steady, IOT) with Add=2D for G1 or prescribed for G2&G3. For each condition, the vertical position-of-use was estimated as the vertical distance (VD) from the mass center of the fixations, projected on the back surface of the lens, to the fitting cross. It was performed independent samples t-test for group comparison and paired t-test for PPL-SV, setting p-value at 0.05
Results :
Considering the use of the PPL for both tasks, the vertical position for each group is G1=1.1±5.2mm; G2=-5.5±7.0mm & G3=-12.5±5.7mm. Users with a required higher addition use a significant lower zone (p-value=0.02 for G1-G2; 0 for G1-G3; 0.02 for G2-G3). When considering the tasks individually G2 uses a lower zone when using the PC (VD=-11.8±2.5mm) compared with the TV (VD=0.8±2.4mm) although accommodative demand is similar. Results for G3 on the PC (VD=-15.7±5.0mm) and the TV (VD=-9.3±4.7mm) indicate a lower zone-of use on PC, likely due to screen position and experiment setup ergonomics. SV lenses yield similar positions between presbyopic (G2&G3) and G1 users when tested on TV, but distinct positions of use on PC
Conclusions :
The wearable ET method identifies regions-of-use in various ophthalmic lens types under diverse natural visual tasks. The experiment distinguishes positions-of-use with SV and PPL lenses for different tasks for presbyopic and non-presbyopic subjects. Parameters influencing the position-of-use include visual task, prescribed addition, and lens type, impacting both addition and ergonomics. These results suggest wearable ET can record lens regions-of-use during tasks, which can be incorporated into the lenses' design
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.