Abstract
Purpose :
To restore age related loss in HA levels in the vitreous of the presbyopic monkey eye to determine if intravitreal injection of HA restores the accommodative response.
Methods :
We injected 0.3ml of HA (14mg/ml; Healon GV) into the vitreous near the optic nerve region, quantified the accommodative response to i.v. pilocarpine (2mg/kg wt) before and after HA injection, and compared accommodative responses at both time points. Accommodative amplitude was measured by Hartinger coincidence refractometry. Accommodative movements of the lens, and ciliary muscle were measured by ultrasound biomicroscopy (UBM; 50, 20 MHz) and choroidal movements in the region of the optic nerve were measured by OCT.
Results :
Two weeks following HA injection the accommodative response to pilocarpine increased dramatically compared to baseline (ipsilateral eye; pre-HA); lens thickening ([increased] by 0.32= 0.07mm), forward ciliary muscle movement (by 0.36 + 0.01mm), centrifugal choroidal movement around the optic nerve (by 0.66 + 0.19mm) and accommodative amplitude (by 3.25 ± 0.50 diopters (p=0.10; n=2), and the anterior lens surface became more sharply curved (by 3.2 ± 0.32 mm radius of curvature). The HA effect was maintained six weeks following injection. The accommodative response in the control eye did not change. Further data is being collected in 4 additional monkeys and the results will be presented.
Conclusions :
The data suggest that HA levels are important to accommodative movements of the lens, muscle and for accommodative amplitude. These experiments may provide insights into presbyopia therapy, the mechanisms of accommodation, presbyopia, accommodating IOL function and perhaps glaucomatous optic neuropathy.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.