Dorzolamide/timolol plus latanoprost is an effective second-line therapy for open-angle glaucoma

This prospective, placebo-controlled, crossover study randomized patients who were insufficiently controlled on latanoprost monotherapy to either dorzolamide/timolol (DTFC) or latanoprost/timolol fixed combination (LTFC) or DTFC and latanoprost.

After three months, patients were then crossed over to the next treatment.  All three adjunctive therapies significantly decreased IOP compared with latanoprost alone, but the addition of DTFC to latanoprost resulted in the greatest IOP reduction. 

The authors conclude that based on the extent of pressure reduction demonstrated in this study, a physician should be able to better judge the second-line therapy that should best achieve an individual patient's pressure goal, by either replacing latanoprost with a fixed combination or by adding dorzolamide based fixed combination.

Still, they say, more research is required generally to determine the best stepwise approach in the treatment of open-angle glaucoma.