Effect of Age on Latanoprost 0.005% in Patients With Glaucoma

Latanoprost is a topical ocular hypotensive medication with a well established safety and efficacy profile. Its effect is mediated by an increase in uveoscleral outflow, due to enzymatic degradation of the extracellular matrix within the ciliary muscle. Since the amount of extracellular matrix within the human eye increases with age, and uveoscleral outflow decreases with age, it would be expected that there should be a difference in the efficacy of latanoprost in patients of different ages. This has not been demonstrated in studies assessing the overall effect of latanoprost across adult age groups using multivariate analysis. (Camras CB et al, 1996).

However, a difference in timing of onset of drug effect may get overlooked in clinical studies and in clinical practice as well, as patients tend to be seen from two to eight weeks after initiation of treatment, by which time any differences in response time may have already occurred and leveled off.

To our knowledge, there are no studies specifically looking at the timing of onset of drug effect of latanoprost in different age groups. Because of the theoretical plausibility of this effect based on the mechanism of action of latanoprost, this represents an opportunity to further elucidate the characteristics of this medication in a manner which has clinical and scientific relevance.

Our aim is thus to determine if there is a difference in timing of onset of the ocular hypotensive effect of latanoprost in glaucoma patients of different age groups.

Inclusion criteria

• diagnosis of open angle glaucoma,
• pseudoexfoliation glaucoma, pigmentary glaucoma or ocular hypertension in one or both eyes;
• IOP above their target pressure as determined by a glaucoma specialist;
• willingness to participate in the study.

Exclusion criteria

• hypersensitivity to any of the components of the treatment medication;
• previous use of topical prostaglandins;
• documented ocular infection or intraocular inflammation within the past year;
• previous filtering surgery or complicated cataract surgery;
• active corneal disease;
• presence of cystoid macular edema;
• laser trabeculoplasty or any other ocular laser procedure within the past three months.