From the 2024 HVPA National Conference
Isabel Hsu A.B. (University of Michigan), Amy Zhang M.D.
Background:
Cataracts are a major cause of vision loss worldwide. The gold-standard treatment is cataract surgery, one of the most common surgeries. The standard procedure requires the use of tropicamide and phenylephrine eye drops for pupillary dilation. These medications are stored in separate containers and administered in sequence. By switching to a combined formulation, surgeons can decrease the economic and environmental costs of ophthalmologic care without adversely impacting patient outcomes.
Methods:
This quality improvement study used a deidentified cohort discovery tool. Patient outcomes were represented by the proportion of complex cataract surgeries (CPT 66982 vs. standard CPT 66984), which involve the use of iris hooks or Malyugin rings for insufficiently dilated pupils. The study period was two years before and after a surgeon decided to switch to combined eye drops. Based on a non-inferiority boundary of odds ratio 1.25 for complications, we aimed to collect n ≥ 3,000 in both comparison groups for a power of 0.883. Demographic information and relevant comorbidities were collected for groups larger than 10 patients.
Results:
Data from 7,811 patients were collected, of which 3,625 were before switching formulations and 4,186 were after (Table 1). The mode for participant age was between 71 and 80 years in both groups. Fifty-five percent of participants were female. Across groups, 47 percent of patients had diabetes and 71 percent had hypertension. Six percent were Black or African American, 3 percent were Asian American, 1 percent were unknown, and 82 percent were white. One percent were Hispanic or Latino, 92 percent were not Hispanic or Latino, and 1 percent had unknown ethnicity. Of note, sets of fewer than 10 individuals were assumed to be 0 to protect patient confidentiality. Thus, percentages may not add up to 100 percent.
Across surgeons, 16.5 percent of cataract surgeries were coded as complex (S.D. = 6.5 percent) before switching and 15.3 percent (S.D. = 6.1 percent) after, on average. A paired Student’s t-test with two-tailed distribution shows a p-value of 0.35 across n = 12 surgeons. Thus, the proportion of complex cataract surgeries did not significantly increase after switching. Combination dilating eye drops were not significantly inferior to the standard regimen in requirement for iris hooks or Malyugin rings.
Conclusions:
Switching from individual bottles to a tropicamide-phenylephrine combination eye drop did not adversely affect surgical complexity. Separate bottles require twice the labor of ordering, inventorying, storage, and restocking in addition to intraoperative administration. Use of a single container decreases plastic waste and cost of care. The decision to switch remains at the individual surgeon level, but has broader implications for workforce productivity, health care costs, and environmental footprint. This study at a large academic medical center in the United States demonstrates that combined tropicamide-phenylephrine drops are not inferior to the standard regimen of separate drops in cataract surgery.