Role of central corneal thickness in circadian intraocular pressure fluctuations among patients with primary open angle glaucoma

الملخص EN

-Objectives: To determine how central corneal thickness in patients with primary open-angle glaucoma correlates with intraocular pressure diurnal fluctuations.

This study also verifies the effect of positioning (supine or sitting) on intraocular pressure.

Methods: This study was conducted on a 38 subjects with mild to moderate primary open angle glaucoma were recruited and evaluated for 24 hours in a controlled environment, having their intraocular pressure measured.

During the hours of 7:00 AM to 9:00 PM, intraocular pressure was measured in the sitting and supine positions, while in the hours of 11:00 PM to 5:00 AM they were made in the supine position only.

Patients were maintained on their normal medication schedules.

Baseline information was gathered from clinical charts in addition to a detailed patient history.

Results: The mean circadian intraocular pressure fluctuation was 8.8 (3.2) mmHg (p<0.0001).

Night time intraocular pressures were on an average 2.3 (2.6) mmHg higher than day time pressures (p<0.0001).

Daytime supine pressures were significantly higher than sitting by 2.8 (1.1) mmHg, (p<0.0001), but daytime supine mean IOP 19.9 (4.0) mmHg was lower than night time supine intraocular pressure of 20.8(4.3), (p=0.04).

Intraocular pressure fluctuations were greater among patients with thinner central corneas.

Inverse relationship was observed between central corneal thickness and daytime supine intraocular pressure flux (Spearman rho= - 0.39, p=0.02) and between central corneal thickness and night time supine intraocular pressure flux (rho = - 0.37, p=0.02).

Conclusion: This study has shown that significant fluctuations in intraocular pressure still occur in clinically controlled patients with primary open-angle glaucoma.

And that those patients with thinner corneas show greater diurnal intraocular pressure fluctuations than patients with thicker corneas.

Furthermore, supine intraocular pressure measurement may provide a more clinically relevant picture in those patients, as compared to sitting pressures.