Factors associated with short and long term IOP fluctuation.

Abstract

Purpose : Attempts have been made to determine the association between ocular and systemic factors with IOP (long-term and short-term fluctuation, peak and mean IOP). However, IOP varies during the day and many previous studies have failed to obtain representative measures of different time points during the day over years in patients with and without glaucoma. This study analyzed patients with multiple diurnal IOP curves to determine ocular and systemic factors that might impact IOP.

Methods : IOP measurements of a minimum of three diurnal IOP curve visits were obtained from a retrospective cohort of 456 patients (912 eyes) who attended from 1984 to 2021 with the diagnosis of different types of glaucoma or glaucoma suspect. Exclusion criteria were a positive history of filtration surgery, any type of cataract extraction surgery within a year before first IOP measurement and a change in medical treatment or surgery during the follow up period. IOP was measured in both eyes in each visit with Goldmann applanation tonometry at 07:00, 09:00, 11:00, 13:00 and 15:00 hours. Ocular variables acquired were lens status, axial length (AL), spherical equivalent (SE) and optic disc diameter. Systemic variables were age, sex, smoking, diabetes mellitus type 2 (T2DM) and systemic arterial hypertension (SAH). IOP variables calculated for each eye were mean IOP (mean of all IOP measurements), mean peak IOP (mean of diurnal curve peaks), long term fluctuation (standard deviation of all IOP measurements) and short term fluctuation (mean of diurnal curve fluctuations). All IOP variables were analyzed using generalized estimating equations accounting for the relationship between both eyes of the same patient.

Results : The mean time between first and last diurnal IOP curve was 29.9 months (SD 28.8). For all subjects, mean IOP in mmHg (SD) was 14.4 (2.9), long-term fluctuation 1.8 (0.8), short-term fluctuation 2.6 (1.1), and peak IOP 15.7 (3.2). Increased age was associated with lower IOP, however it was not significant after adjustment with lens status. Pseudophakic patients had a lower IOP for all variables, except for long term fluctuation. The remaining variables were not associated with any of the IOP variables studied. (Table 1-2)

Conclusions : Age has no effect in IOP when adjusted for lens status, pseudophakic patients have a lower short term fluctuation, mean, and peak IOP. SE, AL, T2DM, SAH, smoking, and disc diameter have no effect in IOP.

This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.