Corneal oblique astigmatism changes result from advancing age, which include an against-the-rule shift and an increase in irregular astigmatism, according to research published in Eye. The incidence of oblique astigmatism is greater in the temporal side meridians, and while men have a higher incidence earlier in their lives, the incidence among women increases with advancing age, according to the report.
Investigators enrolled 1000 patients (56% women; mean age, 67.5 years) with corneal oblique astigmatism in a cross-sectional cohort study and performed videokeratographic examination. The team stratified participants according to astigmatism meridian (31°–45°; 46°–59°; 121°–135°; and 136°–149°) and compared regular and irregular astigmatism, and vertical, horizontal, and oblique astigmatism components among the 4 groups while considering age, sex, and eye side (right vs left).
Corneal oblique astigmatism incidence rates between the 4 meridian categories did not differ significantly among age groups or between sexes. This incidence was significantly higher among eyes with an oblique astigmatism between 31° and 59° in the left eye and 121° to 149° in the right eye. Men had a higher incidence of corneal oblique astigmatism at an earlier age compared with women (beginning age 40 years), but a transition toward increased incidence among women began around age 60 years and persisted into their 70 s and 80 s (P <.0001), where they demonstrated a greater incidence than men.
The amount of corneal oblique astigmatism increased with age, demonstrating a shift toward against-the rule astigmatism and increased irregular astigmatism, according to the report.
“These findings are clinically relevant when performing correction of preexisting oblique astigmatism at the time of cataract surgery, including the use of a toric intraocular lens or limbal relaxing incisions,” according to the researchers. “For example, on the basis of the findings of the present study, preexisting oblique astigmatism should be fully corrected or overcorrected because the oblique astigmatism may increase again after surgery.”
The study’s cross-sectional nature is an acknowledged limitation to the research.
Hayashi K, Uno K, Manabe SI, Hirata A. Prevalence and characteristics of oblique astigmatism. Eye (Lond). Published online March 16, 2023. doi:10.1038/s41433-023-02470-7