Effects of Topical Latanoprost on Intraocular Pressure and Myopia Progression in Young Guinea Pigs

PURPOSE. To determine whether latanoprost, a prostaglandin analog proven to be very effective in reducing intraocular pressure (IOP) in humans, can also slow myopia progression in the guinea pig form deprivation (FD) model. METHODS. Two-week-old pigmented guinea pigs underwent monocular FD and daily topical latanoprost (0.005%, n = 10) or artificial tears (control, n = 10) starting 1 week after the initiation of FD, with all treatments continuing for a further 9 weeks. Tonometry, retinoscopy, and high-frequency A-scan ultrasonography were used to monitor IOP, refractive error, and ocular axial dimensions, respectively. RESULTS. Latanoprost significantly reduced IOP and slowed myopia progression. Mean interocular IOP differences (+/-SEM) recorded at baseline and week 10 were -0.30 +/- 0.51 and 1.80 +/- 1.16 mm Hg (P = 0.525) for the control group and 0.07 +/- 0.35 and -5.17 +/- 0.96 mm Hg (P < 0.001) for the latanoprost group. Equivalent interocular differences for optical axial length at baseline and week 10 were 0.00 +/- 0.015 and 0.29 +/- 0.04 mm (P < 0.001; control) and 0.02 +/- 0.02 and 0.06 +/- 0.02 mm (P = 0.202; latanoprost), and for refractive error were +0.025 +/- 0.36 and -8.2 +/- 0.71 diopter (D) (P < 0.001; control), and -0.15 +/- 0.35 and -2.25 +/- 0.54 D (P = 0.03; latanoprost). CONCLUSIONS. In the FD guinea pig model, latanoprost significantly reduces the development of myopia. Although further investigations into underlying mechanisms are needed, the results open the exciting possibility of a new line of myopia control therapy.