Abstract
Purpose :
To investigate the change in pupil barycenter during dynamic pupil responses and its role in the customization of multifocal soft contact lenses (MFSCL) for myopia control.
Methods :
Dynamic pupillometry was performed on 6 eyes of 3 subjects in mesopic conditions. 3 consecutive measurements were acquired to test for the potential adaptation to repeated flashes of light. Test was then repeated with the contralateral eye occluded to investigate the impact of ambient lighting to the untested eye. Repeated ANOVA was conducted to test the impact of consecutive measurements and paired t-test was performed to test the effect of occluding the untested eye. 3 different MFSCLs were fitted on 6 eyes of 3 subjects followed by a detailed evaluation of centration and movement.
Results :
There was no statistically significant difference of either the maximum or minimum pupil diameter (PDmax and PDmin) of both eyes among 3 consecutive measurements (45 seconds apart) Wilks' Lambda p = .78, .33, .09, and .80 for PDmax and PDmin of OD and OS, respectively. However, there was a consistent trend of larger PD with the untested eye occluded (0.32+/-0.21mm and 0.15+/-0.06mm for PDmax and PDmin, respectively). The difference was significant for PDmin OD (p = 0.035) and PDmax OS (p= 0.043). There was a consistent trend of temporal and superior displacement of pupil center during constriction for both eyes (Δx 0.17+/-0.03; Δy 0.15+/-0.22), which was significant for OD (p<0.005 for Δx and =0.037 for Δy). All 3 MFSCLs showed consistent inferior and temporal decentration (0.35+/-0.25mm horizontally and 0.48+/-0.20mm vertically) with mean range of movement of 0.40+/-0.30mm horizontally and 0.61+/-0.36mm vertically.
Conclusions :
There was no apparent dampening effect with consecutive measurements that were 45 seconds apart, indicating repeatability of dynamic pupil testing. With the contralateral eye occluded, PDmax and PDmin were larger than without occlusion, suggesting that ambient light affects the consensual pupil response. Pupil barycenter showed superotemporal displacement during pupil constriction. Combined with the consistent pattern of inferotemporal decentration of MFSCLs, dynamic pupillometry and diagnostic fitting of MFSCL should be considered prior to customizing a displaced optic center MFSCL design for better alignment to the patient’s pupil center and better predictability of imposed defocus as a myopia-inhibiting signal.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.