Efficacy of topical timolol eye drops for the treatment of diabetic macular edema

Written by: Prethy Rao, MD

Falavarjani K.G., Hadi Y., Habibi A., Anvari P., Modarres M., Parvaresh M.M.,Jafari S. & Alemzadeh S.A. Ophthalmol Retina. 2019 Jun;3(6):538-539

We live in an exciting time in retina with new pathway drugs being rolled into clinical trials and markets—from TIE2 receptors, DARPins, smaller VEGF antibody fragments (conbercerpt, brolicizumab) etc—for both macular degeneration and diabetic macular edema. Beta blockers are just one more rising class of drugs that are being thrown into the mix, specifically for diabetic macular edema, as beta 2 adrenergic receptors play a role in VEGF expression.

In this month’sOphthalmology Retina accepted manuscripts (ahead of print), Falavajani and colleagues performed a prospective non-randomized, comparative case series that evaluated the role of topical timolol maleate drops(0.5%,1 drop twice daily for 3 months) for the treatment of non-central involving diabetic macular edema. Exclusion criteria were those with a history of intravitreal injections, laser in the upcoming 6 months, other eye pathology, systemic beta blocker use, or other anti glaucoma medications. Non-central edema was defined as thickness above a threshold value in either the superior, inferior, nasal or temporal subfields and a central subfield thickness of 350microns.

Of the 39 eyes (20 eyes on timolol, 19 control eyes), no eyes progressed to central macular edema requiring an intravitreal injection. However, those that received topical timolol had statistically significant lower maximum retinal thickness (MRT) and mean subfield retinal thickness (MST) compared to the controls. In other words, the change in the“highest retinal thickness in any subfield” (MRT) and the change in the mean subfield that contained the maximum retinal thickness point (MST) were lower in the timolol group at 1month and 3 months.

While there have been some studies that have evaluated oral or topical beta blockers for retinal neovascularization, this current series appears to be the first to evaluate a topical agent for macular edema. This begs the question—are we entering yet a new era of drug classes that can be used to battle diabetic macular edema and possible AMD?Should we offer a less invasive topical solution for patients with mild macular edema who are wary of intravitreal injection treatment options?Larger prospective, randomized prospective studies will hopefully help us determine these answers.