Abstract
Purpose :
a) to study the safety and tolerability of the eye drops in guinea pigs in vivo, b) to study the effect of eye drops on spontaneous myopia in albino guinea pigs.
Methods :
The safety and efficacy of IVMED-85 (copper formulation) were investigated in albino guinea pigs (pups) starting at age 1 week. Spontaneous myopic albino guinea pigs were used as a model of pediatric myopia. Spontaneous myopia is potentially of high interest because this type of myopia may be more similar to human myopia than experimentally-induced versions.
In general pups were housed in a 12h light/12h dark cycle. In all pups, one eye was control either vehicle or left untreated. The other eye was treated with IVMED-85 eye drops twice a day for approximately 8-10 weeks. We examined: 1) refractive error and axial length and 2) corneal curvature and central corneal thickness. Instruments used were streak retinoscopy for refractive error, Lenstar for axial length and central corneal thickness and Keratron handheld topography for cornea curvature. Measurements were taken between 5-7 days of age (baseline-no treatment) and then weekly or biweekly after eye drops.
Guinea pigs were tested for serum copper at baseline and at end point for copper toxicity. Intraocular pressures (IOPs) was measured with a floating tip tonometer prior to treatment and every 2 weeks. Safety observations of the cornea and score irritation of conjunctiva and sclera including redness, chemosis, and discharge was performed bi-weekly. Histopathological analysis (n=2) was evaluated by ophthalmologist in all dissected eye tissues. Topography images were taken before treatment and bi weekly for 8 weeks.
Results :
Histopathological analysis demonstrated no observed toxicity in all dissected eye. IOP measurements were within normal limits 15-25 mmHg for all eyes during the study. IVMED-85 was effective in reducing myopic progression in the treatment eye while the contralateral eye in same guinea pig continued to become more myopic. There was no difference in axial length between treatment and control eyes. IVMED-85 was effective in decreasing the corneal curvature compared to control eye.
Conclusions :
We propose a novel topical eye drop for the treatment of pediatric myopia. IVMED-85 will induce flattening of corneal curvature and reduction of myopia. These topical treatments will enable a non-invasive and relatively cost-effective treatment for myopia without cycloplegia.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.