Abstract
Purpose :
To estimate anterior segment geometry upon accommodative demand for different ages, which will give insights on new strategies for presbyopia correction
Methods :
43 subjects participated in the study (ages 21 to 64; SE: +1.25 to 8.25D). Images of the eye’s anterior segment were obtained while the subject viewed monocularly a Snellen E-letter, using custom 3-D spectral Optical Coherence Tomography (s-OCT, 840 nm, 25000 A-scans/s, axial range: 7 mm, axial pixel resolution: 3.4 um). 5 measurements (3-D images) were acquired (300 A-scans x 50 B-scans, 11-mm lateral range) for each of the different accommodative demands induced with a Badal optometer: 0-6 D (1 D-steps). Custom algorithms were used for geometrical quantification of Anterior Chamber Depth (ACD), Lens Thickness (LT), Anterior Lens Radius (RAL) and Posterior Lens Radius (RPL). Change of these geometrical parameters in the non-accommodative sate (0D) with age, and change of the parameters per diopter of accommodative demand (acD) with age (i.e., how the geometry changes in response to an accommodation stimulus as a function of age) were evaluated in terms of linear correlations. Equation of the best fitting line, Pearson correlation coefficient (r), and p-values for testing the hypothesis of no correlation were obtained
Results :
For the non-accommodative state (0D), LT increased significantly with age (p<<0.01; LT=3.16+0.02*age; r=0.76), and the rest of parameters decreased significantly with age: ACD (p<0.01; ACD=3.38-0.008*age; r=-0.37), RAL (p<<0.01; RAL=13.07-0.06*age; r=-0.56) and RPL (p<<0.01, RPL=6.79-0.012*age; r=-0.51). Changes of the parameters per diopter (mm/D) with age were also obtained. ΔLT/acD decreased significantly with age (p<<0.01; ΔLT/acD=0.11-0.0018*age; r=-0.84), and the rest of parameters increased significantly with age: ΔACD/acD (p<<0.01; ΔACD/acD=-0.06+0.00096*age; r=0.75), ΔRAL/acD (p<<0.01; ΔRAL/acD=-1.14+0.02*age; r=0.83) and ΔRPL/acD (p<<0.01; ΔRPL/acD=-0.32+0.006*age; r=0.71). No parameter changed significantly with accommodative demand from around 55-60 y.o.
Conclusions :
All the analyzed geometrical parameters decreased significantly with age in the non-accommodative state (0D) except for the LT, that increased, so that the lens becomes more rounded with age. Besides, changes of all the parameters in response to an accommodation stimulus are smaller in absolute value with age, leading to presbyopia around 55-60 y.o.
This is a 2021 ARVO Annual Meeting abstract.