Medication Adherence & Special-Population Management

Why Adherence Fails

Complex multidrug dosing schedules are among the most consistently cited barriers to adherence in glaucoma. The deeper problem is structural. Early glaucoma is typically asymptomatic, so patients get no immediate symptomatic feedback reinforcing daily drop use, unlike a painful condition where the medication's effect is felt directly. Framing glaucoma as a chronic, lifelong condition requiring ongoing therapy, comparable to hypertension or diabetes rather than something curable, sets realistic expectations and supports long-term compliance. Depression predicts worse adherence independent of actual visual impairment, which makes mental health status worth screening for as a modifiable risk factor.

Adjusting Therapy by Patient

• Elderly with reactive airway disease: topical beta-blockers such as timolol are absorbed systemically via the nasolacrimal duct and can precipitate bronchospasm in patients with asthma or COPD, a risk compounded by the reduced physiologic reserve common in older patients.
• Chronic kidney disease: oral carbonic anhydrase inhibitors such as acetazolamide are renally cleared and can cause significant metabolic acidosis and electrolyte disturbance when renal function is impaired. Topical CAIs or an alternative drug class are generally preferred instead.
• Pseudophakic patients: prostaglandin analogs raise the risk of cystoid macular edema in pseudophakic or aphakic eyes, likely through prostaglandin-mediated breakdown of the blood-retinal barrier. Monitor when starting a PGA in this subgroup.
• Cognitively impaired patients: selective laser trabeculoplasty (SLT) is often favored as a first-line intervention because it doesn't depend on daily patient compliance, sidestepping the adherence problem entirely.
• Anticoagulated patients (for example, warfarin for a mechanical heart valve) who need trabeculectomy: coordinate perioperative anticoagulation management with the prescribing physician. Abrupt discontinuation risks thromboembolic events, while continued anticoagulation raises bleeding risk during bleb-forming surgery, so this decision is never made unilaterally.

Switching vs. Adding Therapy

When a patient on maximally tolerated monotherapy still progresses despite adequate IOP lowering, the usual next step is switching to a different drug class rather than adding a second medication outright. The goal is identifying the single most effective monotherapy before committing to combination treatment (see Anti-Glaucoma Medications for the individual drug classes).