Effect of five years of treatment with nipradilol eye drops in patients with normal tension glaucoma

Pressure Clamping During Ocular Perfusions Drives Nitric Oxide-Mediated Washout

Purpose

The aim of this study was to test the hypothesis that nitric oxide (NO) mediates a pressure-dependent, negative feedback loop that maintains conventional outflow homeostasis and thus IOP. If true, holding pressure during ocular perfusions will result in uncontrolled production of NO, hyper-relaxation of the trabecular meshwork, and washout.

Methods

Paired porcine eyes were perfused at constant pressure of 15 mm Hg. After 1 hour acclimatization, one eye was exchanged with N5-[imino(nitroamino)methyl]-L-ornithine, methyl ester, monohydrochloride (L-NAME) (50 µm) and the contralateral eye with DBG, and perfused for 3 hours. In a separate group, one eye was exchanged with DETA-NO (100 nM) and the other with DBG and perfused for 30 minutes. Changes in conventional outflow tissue function and morphology were monitored.

Results

Control eyes exhibited a washout rate of 15% (P = 0.0026), whereas eyes perfused with L-NAME showed a 10% decrease in outflow facility from baseline over 3 hours (P < 0.01); with nitrite levels in effluent positively correlating with time and facility. Compared with L-NAME-treated eyes, significant morphological changes in control eyes included increased distal vessel size, number of giant vacuoles, and juxtacanalicular tissue separation from the angular aqueous plexi (P < 0.05). For 30-minute perfusions, control eyes showed a washout rate of 11% (P = 0.075), whereas DETA-NO-treated eyes showed an increased washout rate of 33% from baseline (P < 0.005). Compared with control eyes, significant morphological changes in DETA-NO-treated eyes also included increased distal vessel size, number of giant vacuoles and juxtacanalicular tissue separation (P < 0.05).

Conclusions

Uncontrolled NO production is responsible for washout during perfusions of nonhuman eyes where pressure is clamped.

Effects of BAK-free travoprost treatment for 3 years in patients with normal tension glaucoma

BACKGROUND

The purpose of this study was to evaluate the effects of benzalkonium (BAK)-free travoprost monotherapy administered for 3 years on intraocular pressure and visual field performance.

METHODS

The intraocular pressure of 76 patients with normal tension glaucoma was monitored every 1-3 months. A Humphrey visual field test was performed every 6 months after treatment and compared with the results before treatment. Visual field performance was also evaluated by trend and event analysis.

RESULTS

Thirty cases discontinued within 3 years. Mean intraocular pressure after 3 years of travoprost treatment (14.1 ± 2.4 mmHg) was significantly lower than that before treatment (16.8 ± 2.6 mmHg, P < 0.0001). There was no change in the mean deviation and pattern standard deviation as measured by Humphrey visual field test after 3 years of treatment compared with before treatment. Visual field performance was worse in one patient (2.8%) by trend analysis and five patients (13.9%) by event analysis. Treatment was discontinued in six cases (7.9%) due to the appearance of adverse reactions.

CONCLUSION

BAK-free travoprost monotherapy was effective in reducing intraocular pressure for at least 3 years; however, visual field performance worsened in 2.8%-13.9% of patients with normal tension glaucoma.