Restoring sensitivity to timolol after long-term drift in primary open-angle glaucoma.

Area of Science:

• Ophthalmology
• Glaucoma Research
• Pharmacology

Background:

• Primary open-angle glaucoma (POAG) management often involves topical timolol.
• Long-term timolol use can lead to diminished efficacy, necessitating treatment adjustments.
• Intraocular pressure (IOP) control is crucial to prevent glaucoma progression.

Purpose of the Study:

• To investigate the impact of a temporary timolol withdrawal (a "timolol holiday") on IOP control in POAG patients.
• To evaluate the effect of adding dipivefrin during the timolol holiday on subsequent timolol response.
• To determine if the duration of the timolol holiday influences the re-instated timolol efficacy.

Main Methods:

• Prospective, randomized, single-masked study over 6 months.
• 39 eyes with POAG on chronic 0.5% timolol underwent a 30 or 60-day timolol holiday.
• 23 eyes received 0.1% dipivefrin twice daily during the holiday; 16 did not.

Main Results:

• Restoring timolol led to a greater IOP decrease in the dipivefrin group (8.2 +/- 1.5 mmHg) compared to the non-dipivefrin group (3.9 +/- 1.2 mmHg).
• The IOP reduction in the non-dipivefrin group was less pronounced and shorter in duration (<60 days).
• In the dipivefrin group, a 60-day holiday resulted in a more prolonged IOP reduction, with IOP remaining <23 mmHg throughout follow-up.

Conclusions:

• A temporary discontinuation of timolol, especially when combined with dipivefrin, can re-sensitize the eye to timolol's IOP-lowering effects.
• Dipivefrin use during a timolol holiday enhances the subsequent response to timolol therapy in POAG.
• A 60-day timolol holiday with dipivefrin appears most effective for achieving sustained IOP control in POAG patients.