Abstract
Purpose :
To systematically study anterior segment changes during dynamic, long-range accommodation.
Methods :
Design: Prospective, observational study.
Participants: A total of 26 young, healthy, third-decade subjects with less than ±0.5D refractive error.
Methods: On swept-source anterior segment optical coherence tomography (CASIA-2, Tomey Corp, Japan), anterior segment structural changes were recorded on accommodation, from baseline (0 diopter) to 8 diopters.
Main outcome measures: Software generated automated changes in corneal thickness and volume, anterior chamber depth and area, iris area and curvature, lens curvature, lens thickness, lens tilt and decentration at each diopter, and qualitative changes in the ciliary body were noted.
Results :
Results: 52 eyes of 26 subjects were evaluated, with mean age of 25.92±1.64 years. Each successive dioptric accommodative stimulus from baseline, lead to progressive decremental responses in anterior lens curvature (p<0.001), posterior lens curvature (p<0.001), anterior chamber depth (p<0.001) and anterior chamber area (p=<0.05) with corresponding, incremental responses in lens thickness (p<0.001) noted till 8D. However, the overall and inter-dioptric responses were more significant during the initial phases of stimulation, up to 4D, as compared to later. Likewise, iris (nasal and temporal) curvature (p<0.001) and area (p<0.001) also showed dynamic changes in a coordinated manner. Cornea and anterior chamber width changes were statistically insignificant, even though fluctuations were noted at higher dioptres.
Conclusions :
Conclusions: On progressively increasing accommodation, initial significant changes were seen as primarily lenticular, complementary anterior chamber and associated iris changes. Whereas, accommodation at higher diopters showed significantly altered lens position and other complex anterior segment structural changes.
This is a 2021 ARVO Annual Meeting abstract.