Authors: Matthew P. Quinn, Marlo Whitehead, Sudeep Gill, Erica de L.P. Campbell, Robert J. Campbell

Author Disclosure Block: M.P. Quinn: None. M. Whitehead: None. S. Gill: None. E. de L.P. Campbell: None. R.J. Campbell: None.

Abstract Body:

Purpose: To examine trends in the distribution of new glaucoma patients and new glaucoma suspects between ophthalmologists and optometrists in Ontario; and, to determine patient-level predictors of provider type.

Study Design: Longitudinal, retrospective, population-based study using provincial health care databases.

Methods: Ontario Health Insurance Plan beneficiaries over 65 years of age were included. Population-based rates of new diagnosis of glaucoma or glaucoma suspect status with and without therapy initiation (i.e. first-ever medication or laser trabeculoplasty) were obtained using population-wide databases from 2007 to 2017. Logistic regression was used to assess factors associated with type of provider. Institutional REB approval was obtained.

Results: A total of 362,174 persons were diagnosed with and/or initiated therapy for glaucoma. Over the study period, the rate of diagnosis without therapy initiation by an ophthalmologist increased from 366 to 503 per 100,000 population, and by an optometrist from 367 to 433 per 100,000 population. Over the same period, the rate of glaucoma therapy initiation by an ophthalmologist declined from 1003 to 725 per 100,000 population. Before 2011, optometrists in Ontario did not prescribe medications. Subsequently, the rate of glaucoma therapy initiation by an optometrist increased to 94 per 100,000 population in 2017. In this final year of the study, ophthalmologists provided care to 53% of persons receiving a glaucoma diagnosis without therapy initiation and to 88% of persons initiating glaucoma therapy. Predictors for receipt of care from an ophthalmologist included greater age, increasing comorbidity score, female sex, and previous cataract, cornea, or retina surgery. Patients living in rural areas were less likely to receive care from an ophthalmologist (all P <0.0001).

Conclusions: While the majority of care for new glaucoma patients in Ontario is delivered by ophthalmologists, optometrists are playing a growing role. This appears to be predominantly in the diagnosis of glaucoma suspects, especially those who are younger and healthier. Since extension of prescribing privileges in 2011, optometrists in Ontario have been initiating therapy at an increasing rate. Nevertheless, nearly 9 out of 10 patients receiving first-line therapy for glaucoma are treated by ophthalmologists. Overall, the rate of treatment initiation by ophthalmologists in persons over 65 has been declining and this finding bears exploration in subsequent work.