Abstract
Purpose :
The role of high order aberrations (HOA) in refractive error development and progression remains unknown. We hypothesize that HOA affect emmetropization and relate to the degree of refractive error induced in experimental models of myopia. We tested this hypothesis by measuring overall and individual HOA Zernike polynomials through defocus inducing contact lenses longitudinally in common marmosets.
Methods :
HOA, spherical equivalent (SE) and vitreous chamber depth (VCD) were measured under cycloplegia in 12 marmosets treated monocularly with contact lenses (-5D N=5; +5D N=7, contralateral eye was treated with Plano contacts (PL) and served as control) at 70 days of age (baseline, treatment started), 4 and 8 weeks into treatment. HOA, SE and VCD were measured using a COAS G200 (Hartmann-Shack aberrometer), autorefractor (Nidek ARK-900) and A-scan ultrasound respectively.
Results :
Marmosets treated with -5D developed myopia (change in SE and VCD: -4.45±2.29D, 0.64±0.14mm) compared to +5D (change in SE and VCD: 0.52±0.96D, 0.34±0.07mm) and PL (change in SE and VCD: -1.00±1.23D, 0.45±0.09mm), all p<0.001. In all treatment groups, the total and averaged HOA RMS for each order (3rd to 10th order) did not differ between groups (p>0.05). When the individual Zernike polynomials were examined through the contact lenses, only spherical aberration (SA) differed significantly between treatment groups: -5D treated animals developed more negative SA (4-week change: -0.09±0.02µm, 8-week change: -0.13±0.11µm) compared to +5D (4-week change: 0.07±0.12µm, 8-week change: 0.01±0.05µm) and PL (4-week change: 0.00±0.07µm, 8-week change: 0.00±0.06µm), p<0.05. A correlation was observed between the change in SA, VCD (R2=0.40, p=0.002) and SE (R2=0.23, p=0.03). Furthermore, the 4 week change in SE was predicted by the baseline Z(10,-4)(R2=0.31, p=0.006), the 8 week change in SE was predicted by the 4 week Z(9,1), Z(10,4) and Z(10,-4)(R2=0.50, p=0.004), and the 8 week change in VCD was predicted by the SE, VCD and Z(10,6)(R2=0.80, p<0.001) at 4 weeks.
Conclusions :
Defocus-inducing contact lenses do not affect the total and individual order RMS of HOA, but appear to specifically alter SA. Animals treated with negative lenses exhibit a more negative SA, suggesting a potential link between SA change and the development of myopia. Further, some of the 10th order HOA were able to predict future changes in ocular growth and refractive error.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.