Date Published: January 31, 2019
Publisher: Public Library of Science
Author(s): Masahiko Ayaki, Yukari Tsuneyoshi, Kenya Yuki, Kazuo Tsubota, Kazuno Negishi, Sanjoy Bhattacharya.
Prostaglandin analogues (PG) reduce intra-ocular pressure by enhancing uveoscleral flow at the ciliary body, which controls accommodation via the ciliary muscle. We investigated the effect of PG on accommodation and presbyopia progression in glaucoma patients.
We conducted a clinic-based, retrospective, cross-sectional study. Inclusion criteria were bilateral phakic patients aged 40–69 years with best corrected visual acuity better than 20/30. Exclusion criteria were any disease affecting vision other than glaucoma and history of ocular surgery. Subjects with no prescription or vision-affecting disease served as controls (n = 260). The glaucoma patients were prescribed eye drops containing 0.005% latanoprost for more than six months (n = 23). We measured the binocular near add power at a distance of 30 cm in both groups and compared the results using Kaplan-Meier analysis.
The mean age (± SD) of the control subjects was 51.5 ± 5.2 years and 39% were male. Similarly, the glaucoma patients had a mean age of 51.0 ± 7.2 years and 39% were male. There were no significant differences in age, gender, intra-ocular pressure, spherical equivalent, astigmatism, or anisometropia between groups. Survival analysis indicated that the glaucoma patients in this study reached the endpoint (near add power of +3.00 D) significantly earlier than control patients (P = 0.0001; generalized Wilcoxon test).
Exacerbation of presbyopia progression in glaucoma patients is a potential side effect of latanoprost eyedrops.
Presbyopia and glaucoma are typical age-related eye diseases. Presbyopia is the loss of accommodation, and its progression predominantly depends on progressive lens hardening and decreased ciliary muscle mobility. It is an inevitable and irreversible part of the normal aging process, and a huge economic burden worldwide [1–6]. Glaucoma patients tend to be elderly and their visual function may have declined because of visual field loss, cataract, and presbyopia.
Out of 6121 patients who visited the study institute during the study period, 260 control subjects and 23 glaucoma patients were finally analyzed following the stated inclusion and exclusion criteria (Fig 1). Xalatan was prescribed to 17 glaucoma patients and Xalacom was prescribed to 6 patients. Of those patients receiving Xalatan, four used hyaluronate, one used diquafosol, and one used rebamipide to alleviate dry eye. In addition, three patients used cyanocobalamin, levocabastine, and fluorometholone eyedrops, respectively. One patient prescribed Xalacom used hyaluronate. There were no significant differences in age, gender, IOP, spherical equivalent, astigmatism, or anisometropia between the groups (Table 1).
The present study revealed that progression of presbyopia, as indicated by near add power, was accelerated in glaucoma patients with a history of latanoprost eyedrop use compared with healthy subjects with no history of eye disease or eyedrop use. Previous studies [16,19] indicated that latanoprost could reduce accommodation in young subjects after a single instillation and one month of use, and this study is the first study to be conducted in middle- to older aged patients. Although the contractility of the isolated ciliary muscle did not diminish with age, stiffened posterior ciliary muscle attachments might still play a possible role in restricting muscle and lens mobility during accommodation . We speculate that latanoprost induces weak pseudomyopia and contraction of the ciliary muscle that may be reversible in young subjects, but become irreversible in the elderly. Ciliary muscle contraction might also become persistent with long-term latanoprost use. Consequently, long-term use may cause the muscle to stiffen and result in the apparent progression of presbyopia. Participating glaucoma patients used eyedrops other than latanoprost, including timolol malate, fluoromethoron, cyanocobalamine, and lubricating eyedrops. This is a possible confounding factor since a previous study showed some effect on timolol on the flattening of lens and ciliary muscle contraction , although the effect was still less than that of PGs and the other eyedrops have no reported effects on accommodation.