Contrast sensitivity is our ability to differentiate between an object and its background. It affects many of our daily activities, such as reading signs, driving, and walking down a flight of stairs. Contrast sensitivity is also a critical—yet often-overlooked—symptom of glaucoma. In a recent article in Optometry Times, Ben Casella, OD, FAAO, discusses how a patient taught him to pay closer attention to contrast sensitivity in his practice.*

The first exam

A 47-year-old Caucasian male, now 51, approached Dr. Casella in 2015 in search of a comprehensive eye examination and a new, updated pair of glasses. He was nearsighted (myopic) and had difficulty focusing on close objects (presbyopic). His best-corrected visual acuity (BCVA) was 20/20 in both eyes. 

The comprehensive exam revealed that his right optic nerve head had a larger cup and appeared at risk for glaucoma. His retinal nerve fiber layer was also asymmetric, and the patient had no history of trauma. Dr. Casella asked him to return for baseline glaucoma testing within a week or two.

The follow-up

The patient returned four years later in October of 2019. His BCVA remained 20/20 in each eye, and he had no cataracts. Though his left optic nerve appeared largely unchanged, his right optic nerve showed open-angle glaucoma (OAG) that required treatment. 

The patient was given prostaglandin analog drops to administer to his right eye at bedtime, with a goal of 50% reduction in intraocular pressure (IOP). Within a month, the IOP of both eyes was nearly the same. At his three-month follow-up in February 2020, his IOP remained unchanged.

The lesson

What Dr. Casella found intriguing was that the patient hadn’t noticed the visual field defect of his glaucoma. It was the noticeable change in his right eye’s contrast sensitivity that compelled the man to return to the doctor’s office. The patient’s surprising experience taught him the importance of giving contrast sensitivity a more prominent place in all his glaucoma patient interactions.

“I often talk about contrast sensitivity with patients with cataracts, but I am going to do a better job of addressing this aspect of glaucoma, as well,” wrote Dr. Casella.

*Casella, B. P. (2020, June 12). Contrast Sensitivity Manifests in Glaucoma Patient with No Cataracts. Optometry Times. https://www.optometrytimes.com/view/contrast-sensitivity-manifests-in-glaucoma-patient-with-no-cataracts

Any sources from outside of Prevent Blindness do not imply an endorsement from Prevent Blindness. The contents of the material used are the responsibility of the authoring organization, Responsum Health.