A new study has found that adults with diabetes in Ontario are getting significantly fewer government-funded eye exams than they were a decade ago, a key component of high-quality diabetes care essential to preventing diabetes-related eye complications.

The decrease is an unintended consequence of the provincial government's decision in 2004 to delist routine eye exams from the Ontario Health Insurance Plan for healthy adults under age 65, said lead researcher Dr. Tara Kiran.

Routine eye exams continue to be funded for adults with diabetes and other medical conditions that affect the eyes, as well as children, seniors and people on social assistance.

Although the study did not address why the number of eye exams dropped, Dr. Kiran said it was almost certainly related to a misunderstanding by patients and health care providers who may have thought that eye exams done by an optometrist were no longer covered for people with diabetes. Patients with diabetes may also have been charged for a publicly insured service, something she was not able to study.

Dr. Kiran is a family doctor and researcher at St. Michael's Hospital and a research fellow at the Institute for Clinical Evaluative Sciences. Her study was published in the Canadian Medical Association Journal.

"Our findings suggest that delisting worsened the quality of diabetes care in Ontario - even though the policy change was not supposed to affect people with diabetes."

Medical guidelines recommend that people with diabetes have a dilated eye exam every one to two years to screen for diabetic retinopathy. Diabetic retinopathy is the major cause of blindness in people of working age. Early detection and treatment of retinopathy through regular eye exams in which the pupil is dilated can significantly reduce the likelihood of blindness.

Dr. Kiran and her colleagues examined data on publicly funded eye exams of adults aged 40 and over with diabetes in Ontario to determine whether delisting annual exams for healthy middle-age adults affected screening for retinopathy in patients with diabetes. They found that eye exam rates for people aged 40 to 65 years remained steady at 69 per cent between 1998 and 2004 but dropped after delisting to 61 per cent in 2006 and 57 per cent in 2010.

At the same time, rates of cholesterol testing and blood glucose testing, both covered by OHIP, rose steadily from 1998 to 2010. Eye exam rates did not decrease for those 65 and over, a group in which eye exams were not delisted for anyone.

"The Ontario government presumably decided to delist eye examinations for healthy adults because these were deemed to be medically unnecessary," Dr. Kiran said. "Although this likely saved money in the short term, the policy change clearly had unanticipated negative consequences."