I recently read a JAMA Ophthalmology article in which Drs. Hendrik Scholl and Caroline Klaver discuss pentosan and macular disease. Pentosan is a treatment for a chronic bladder condition called interstitial cystitis. The macula is the center portion of the retina.
There seems to be an association between the use of pentosan and disease of the macula. Though this is not a well-established causal correlation yet, as the authors describe, there is definitely reason to be wary of the effect that pentosan can have on the retina. In their article, Scholl and Klaver recommend a baseline retinal exam for all patients when starting pentosan and then annually while continuing treatment.