Retinal Screening Study

The primary purpose of the retinal screening study is early detection of retina and optic nerve diseases, using a very fast routine for evaluation of pupil light reflex. The goal is to establish a procedure for timely diagnosis and treatment, before damage to the retina and optic nerve becomes irreversible. This methodology was developed for veterinary use by Dr. Grozdanic and his team, and demonstrates high accuracy in detecting many common retina and optic nerve problems in veterinary patients.1

We also have a strong interest in early detection of autoimmune retinal diseases, with a specific focus on Sudden Acquired Retinal Degeneration Syndrome (SARDS). Dr. Grozdanic and his team pioneered the method for the detection of SARDS using a chromatic pupil light reflex test a decade ago.2,3

In October 2016, Dr. Grozdanic and his team reported detection of SARDS in dogs that had completely normal day vision (American College of Veterinary Ophthalmology Annual Conference, Monterey, CA). As a result of this work, veterinary ophthalmologists worldwide can now diagnose dogs affected with SARDS at a much earlier stage of the disease.

Dogs diagnosed with SARDS that have normal day vision have an almost 80% chance of keeping their sight if timely medical treatment is initiated. Dogs with this disease have 100% risk of blindness if left untreated, or if treatment is not aggressive or timely.

Dr. Grozdanic and his team are also looking at incidence of retinal toxicity in dogs treated with regular monthly heartworm medications containing ivermectin, and some novel anti-parasitic agents with prolonged delivery mechanism. Over the last five years, clinicians from Animal Eye Consultants of Iowa noticed a significant increase in the number of patients developing visual problems (night vision loss, intermittent night and day vision loss, depth-perception issues), which have been associated with the use of these drugs. In many of these patients, pupil light reflex abnormalities are the very first clinical symptom of the problem.

The goal of the retinal screening study is to enroll approximately 100 general veterinary practices in Iowa, and screen 36,000 veterinary patients during the first year of the study in order to determine incidence of retina and optic nerve diseases, SARDS and heartworm/anti-parasitic medication toxicity in the general veterinary patient population.

For more information about the study and how to participate, please contact Animal Eye Consultants of Iowa. Email: or 1-860-IOWA-EYE, or just visit the study website at:

Retina Screening Study
(click pdf to view or download)

1Grozdanic et al., Vet Ophthalmol. 2012 Sep;15 Suppl 2:94-104
2Grozdanic et al., Invest Ophthalmol Vis Sci. 2007 Nov;48(11):5178-83
3Grozdanic et al., Grozdanic et al, Vet Clin North Am Small Anim Pract. 2008 Mar;38(2):361-87

Instrument instruction use video