Abstract
Purpose :
Acute angle closure glaucoma due to pupillary block is a risk during mydriasis for examination of the posterior chamber (Pandit RJ, et al, 2000). Meta-analysis is a technique to control for variability between studies by weighting them by their study size and variability. Typically this is used to measure effect size, it can also be used to estimate the frequency of disease, such as prevalence and incidence.
Methods :
Sixteen datasets from published clinical studies were analyzed for this study resulting in a population of 594,640. Incidence of narrow angle closure after mydriasis was used as the primary outcome. Individual data set incidence variance was calculated using incidence multiplied by inverse incidence divided by the study size (Barendregt, et al 2013). The meta incidence was then calculated by summing the individual incidence divided by individual variance divided by one over the pooled variance. This process was repeated for all mydriatics combined, and for each individual pharmacological agent. The confidence interval was calculated from the square root of the summed inverse variance.
Results :
Meta-incidence of angle closure was 1 in 18,500 +/-178. Tropicamide with phenylephrine had the highest incidence at 1 in 17,600+/-177. Many pharmacological agents had no incidence of angle closure which is probably due to low sample sizes. Factors increasing the risk of incidence were consistent with previously reported literature including age, gender, and refractive error status. Unsurprisingly, the risk for angle closure due to mydriasis has the highest incidence in patients with previously diagnosed glaucoma.
Conclusions :
In populations with low prevalence of narrow or open angle glaucoma, the risk of angle closure due to mydriasis is very low. The average north American eye doctor sees 6000 patients a year, suggesting a closed angle would occur once every three years if all patients were dilated. In that population, a high percentage would have factors increasing their risk. In populations at increased risk due to age, refractive error, gender and underlying open/closed angle glaucoma, evaluation of the anterior segment is critical before dilation. The lack of incidence of narrow angle glaucoma with many agents is most probably due to low sample sizes and should in no way be considered absolutely safe.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.