The aim of our study was to investigate the role of visual load levels in intraocular pressure (IOP) elevation in patients taking prostaglandin analogs and to try to optimize the conditions for their effects on the uveoscleral outflow.
Material and methods
A total of 33 patients (40 eyes) with first diagnosed primary open-angle glaucoma (POAG) and resistance to latanoprost 0.005 % IOP were included in this study. These patients were pre-examined with the definition of visual and reading acuity, refraction, and true, tolerant, and target IOP with perimetry and ophthalmoscopy. Subjects were divided into two groups of comparable age, sex, and refraction. In each group, the thickness of the ciliary body by ultrasound biomicroscopy was investigated, and the level of near visual load and tolerated correction for near were defined.
It was found that in both groups, 85 % of the eyes with POAG had moderately high (3–6 h per day) and high (> 6 h per day) near visual load. Maximal ciliary body thickness in both groups was significantly higher than the results received by other authors: 0.881 ± 0.039 mm in group 1 and 0.889 ± 0.049 mm in group 2. Also, a direct dependence of the ciliary body thickness on the true value of IOP (r = 0.52) was observed. Hypercorrection of presbyopia was made in group 1 gradually, in steps of 0.25 D. The value of additional correction averaged 0.5 ± 0.13 D. The magnitude of additional correction was inversely related to age (r = 0.79). To assess the effectiveness of presbyopia overcorrection in reducing IOP 1 year later, tonometry, visual acuity check, perimetry (MD/year method), ophthalmoscopy, and measurement of the thickness of the ciliary body were performed. In group 1, the reduction of IOP (17.3 ± 0.84 mmHg) was statistically significant (p < 0.01), and its value was close to the average tolerant IOP (17.0 ± 0.67 mmHg), but was higher than the target (14.3 ± 0.67 mmHg). Also, in this group, statistically significant (p < 0.01) decrease in the thickness of the ciliary body was observed, more marked in patients with high near visual load (r = 0.47). Progression of glaucoma according to perimetry was significantly less (p < 0.01) in the group with hypercorrection of presbyopia as compared with the group with ordinary correction.
Overcorrection of presbyopia, in addition to antihypertensive therapy, may be a way to regulate IOP for patients with high near visual load and POAG.