Losartan is a commonly prescribed oral medication for high blood pressure (hypertension). Now, research by Cleveland Clinic’s Cole Eye Institute suggests that the drug may be effective as an eye drop for reducing scarring in the cornea and restoring vision, even in long-standing cases.*

Three decades of exploratory research

Surgeon Steven E. Wilson, M.D. is the Director of Corneal Research at the Cole Eye Institute. For several decades, his research team has been funded by the National Institutes of Health (NIH) and the Department of Defense to study wound healing in the cornea, as well as drugs that may prevent excessive scarring after injury, surgery, or infection. 

In the process, Wilson’s team has examined how scar tissue-forming cells called myofibroblasts form in the cornea. Knowing that transformative growth factor (TGF) beta-1 and -2 play a critical role in scarring, Wilson theorized that losartan may prevent scar formation, since it inhibits TGF signaling.

Two foundational animal studies were completed.

• The first study, appearing earlier this year in Experimental Eye Research, was done on rabbits that underwent corneal surgery. After a month, corneas given topical losartan were clearer. Scarring was disappearing along the edge, and continuing toward the center. Oral administration of losartan had no effect on the cornea. Wilson said it would “likely take weeks to months” of continuous effect for human patients to see any significant improvement in scarring.
• The second study, appearing over the summer in Translational Vision Science and Technology, experimented with topical losartan and steroids for treating deep burn injuries in rabbit corneas. After a month, corneas given both medications were significantly clearer.
  

Promising in people

Wilson theorized that losartan could benefit any instance of scarring, regardless of how long-standing it was. Physicians in Brazil who were trained by Wilson tested this theory by creating an off-label topical solution of losartan for human use. According to the results:

• One patient developed corneal inflammation after LASIK surgery, leaving severe scarring that reduced vision to 20/200. After five months of losartan eye drop use, full corneal transparency returned and vision was 20/30.
• Another patient had scarring and abnormal new blood vessel growth following surgery. After just 15 days of losartan eye drops, the patient saw a “dramatic” decline in scarring, with more progress observed from continued use.

Though these two cases have yet to be published, Wilson is enthusiastic. “The first two patients are far enough along that we know they have had dramatic clearing. In my experience, no other drug treatment has performed like this.”

Future research

Currently, treating corneal damage involves topical steroids, but they may not completely stop scarring, there are risks to using them, and their effect can be temporary if usage is stopped. On the other hand, Wilson has shown that combining steroids with losartan may be the best approach to corneal scarring with severe inflammation. Wilson and his team plan to start a broader study of this combination therapy soon.

*Cleveland Clinic. (2022, September 7). Hypertension Drug Losartan Reverses Scarring and Restores Vision After Cornea Damage. https://consultqd-clevelandclinic-org.cdn.ampproject.org/c/s/consultqd.clevelandclinic.org/hypertension-drug-losartan-reverses-scarring-and-restores-vision-after-cornea-damage/amp