Treatment decisions of UK hospital optometrists and ophthalmologists in patients with nAMD: a vignette study

PURPOSE: A vignette study to examine treatment decisions made by UK hospital optometrists in patients with neovascular age-related macular degeneration (nAMD) and the effect of optometrists' experience on agreement.

METHODS: Patients with nAMD attending Manchester Royal Eye Hospital, Manchester, UK were identified as potential candidates for the case series of vignettes. The cases were chosen to reflect a varied case-mix with respect to difficulty as well as ensuring good quality of the images. Each vignette included a history summary consisting of the number of previous injections given and visual acuity measurements at baseline, the previous visit, and the current visit. Images were compiled to show baseline fundus photographs and ocular coherence tomography (OCT) images with the current visit images on which the treatment decision was to be made along with the images from the previous visit. Hospital optometrists were recruited and asked to complete the series of vignettes, deciding if treatment was required at that visit and how confident they felt with that decision. Their responses were compared to the reference standard created by a consensus of consultant ophthalmologists with a sub-speciality interest in medical retina.

RESULTS: Regarding treatment decision for optometrists, the percentage correct value was 75% with the sensitivity being 75.6% (95% CI 70.1-80.3) and the specificity as 75.1% (95% CI 72.1-77.8). No statistically significant difference was found between differing levels of experience. However, there was a significant difference in confidence levels between groups. Potentially sight threatening decisions accounted for 6.4% of the optometrists' decisions, 3.5% were made with a high confidence rating suggesting no discussion with an ophthalmologist was required.

CONCLUSIONS: Although the optometrists showed modest agreement with the reference standard in a series of cases that have higher than average complexity, the optometrists showed a similar amount of variability within their treatment decisions compared to the reference standard. The optometrists were therefore not inferior in their performance compared to the ophthalmologists and this can be seen as supporting evidence for their extended role within this clinical area. Experience did not have an effect on 'correct' treatment decisions although there was a statistically significant effect on increasing confidence of treatment decision.