Abstract
Purpose :
To investigate intraocular pressure (IOP) variation according to month and time of year among a primary eye care population in an urban, academic eye care facility.
Methods :
As part of a separate investigation, IOP measurements were collected on patients belonging to several practitioners over approximately a five-year period at an urban, academic eye care facility in Chicago, Illinois. Data on ocular health status, general medical health, and other subject characteristics was also collected, with some information acquired with via a written questionnaire completed at time of examination. Subjects were excluded if they were <18 years of age, and eyes were excluded if there was a history of past intraocular surgery, uveitis, ocular trauma, or if IOP was not measured via Goldmann tonometry. Using multiple regression analysis, cross-sectional IOP level was explored as a function of numerous health and demographic variables.
Results :
The analysis included 2,407 subjects, which was mostly African-American (83%) and female (64%). Mean age of subjects was 50.3 +/- 15.2 years (18-94 years). Overall mean IOP was 15.1 +/- 3.6 mm Hg and 15.2 +/- 3.4 mm Hg for right/left eyes. Controlling for numerous other subject variables, including but not limited to gender, race, refractive error, presence of long anterior lens zonules, education level, smoking status, diastolic blood pressure, presence of diabetes, body mass index, presence of diabetes, and history of cancer, regression analyses demonstrated that IOP level was significantly associated with time of year in terms of quarterly and bimonthly intervals (P<0.001). Using bimonthly grouping that included Dec/Jan, Feb/Mar, Apr/May, etc., eyes had statistically (P<0.05) highest IOPs in Dec/Jan (15.6 +/- 3.6 mm Hg) and lowest in Oct/Nov (14.7 +/- 3.3 mm Hg). In additional to longer term, i.e., seasonal/quarterly variation in IOP, an observable, shorter-term cyclical pattern of IOP variation was also observed that appeared to have about two-month long intervals.
Conclusions :
For this cross-sectional analysis, strong time of year variation in IOP was observed, which was also accompanied by shorter, approximately bimonthly cycles of fluctuation. These data further support that time of year should be considered as a potential confounder for cross-sectional investigations of IOP.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.