Gender gaps in first and last authorship in ophthalmology randomized controlled trials: A two-decade analysis

Purpose To characterize 21-year trends in first- and last-author representation inferred as female in ophthalmology randomized controlled trial reports and examine associations with journal impact factor and first-last author pairing. Methods This repeated cross-sectional bibliometric study identified PubMed-indexed ophthalmology randomized controlled trial reports published from 2004 through 2024. Gender-API assignments were retained at 90% or greater accuracy. Annual proportions and Theil-Sen slopes were calculated, and a publication-year-by-authorship-position interaction tested whether temporal trends differed. Secondary analyses examined journal impact factor, first-last author pairing, geographic composition, and sensitivity to alternative inference thresholds. Results Among 10,887 records, 953 were excluded because neither the first nor last author had a usable given name, leaving 9,934 articles. Qualifying assignments were available for 7,913 first-author and 7,878 last-author positions. Inferred female first authorship increased from 26.2% in 2004 to 38.3% in 2024 (slope, + 0.51 percentage points per year; 95% CI, 0.39 to 0.68; p < 0.001), and last authorship increased from 27.8% to 31.0% (+0.36; 95% CI, 0.10 to 0.57; p = 0.006). The year-by-position interaction was not statistically significant (+0.178 percentage points per year; 95% CI, −0.063 to 0.419; p = 0.148). Journal impact factor was not significantly associated with either authorship position. The adjusted odds of an inferred female last author were higher when the first author was inferred as female (OR, 1.28; 95% CI, 1.10 to 1.49; p = 0.001). Conclusion Representation inferred as female increased in both authorship positions, with no statistically significant difference between temporal trends.