BLOG: Topical prostaglandins and MIGS

Topical prostaglandins have been an effective treatment for glaucoma for a decade. The most common currently used in the United States are latanoprost, travoprost and bimatoprost. The mechanism of action for these drops reduces IOP by stimulating aqueous drainage through the uveoscleral outflow pathway.

While effective, these prostaglandins may cause some adverse effects including conjunctival hyperemia, deepening of the upper eyelid sulcus, eyelash lengthening or bristling, and iris and eyelid pigmentation changes. Additionally, prostaglandins cause significant cellular changes in the outflow pathway tissues. Studies have found that these drugs can cause areas of the ciliary muscle to enlarge and elongate, essentially remodeling the extracellular matrix. These changes increase outflow rates, but also alter outflow pathways tissue permeability.

While this degradation of the extracellular matrix improves aqueous humor outflow through the uveoscleral pathway, it can also make treatment by MIGS procedures such as the iStent (Glaukos) less productive. Therefore, I do not utilize the iStent and searched for simpler methods to treat my glaucoma patients that could relieve them of their medication burden.

I have found laser therapy with Iridex’s MicroPulse technology to be a much safer, effective treatment for my patients. I can typically reduce patient medications by an average of three, which is a significant benefit. The MicroPulse treatments produce equivalent results of a more invasive surgery without the risks inherent with those procedures. I have also come across no reimbursement issues, whether or not the procedure is performed with or without cataract surgery.

References:

Nilsson SF, et al. Invest Ophthalmol Vis Sci. 2006;doi:10.1167/iovs.05-1627.

Richter M, et al. Invest Ophthalmol Vis Sci. 2003;doi:10.1167/iovs.02-1281.

Toris C, et al. Surv Ophthalmol. 2008;doi:10.1016/j.survophthal.2008.08.010.

Weinreb RN, et al. Surv Ophthalmol. 2002;doi:10.1016/S0039-6257(02)00306-5.

Disclosure: Toyos reports she is a speaker and consultant for Valeant and Sun; conducts research for Lumenis, Magellan and Kala; is a speaker and consultant and does research for Shire, Mallinckrodt and MixtoLasering; is a consultant and does research for DigiSight; does research for Novaliq; and is a consultant for Iridex.