Fluctuations in intraocular pressure during body position changes during monotherapy with prostaglandin analogues

Relevance Diurnal fluctuations in intraocular pressure (IOP) can have a destructive effect on the optic nerve [1, 2]. Changes in IOP with a change in body position, for example, during sleep, can lead to disease progression. An accurate study of such fluctuations was not possible due to the lack of devices that work in different positions. Prostaglandin analogues minimize diurnal fluctuations, but this has not been studied with changes in body position [3]. Objective To study the effect of prostaglandin F2α analogues on IOP fluctuations in different body positions. Material and methods The study included 38 patients (50 eyes) with newly diagnosed primary open-angle glaucoma. The examination was conducted before the prescription of a prostaglandin F2α analogue and 1 month after the start of therapy. The examination included IOP measurement in the sitting position with an Icare contact tonometer and a Reichert 7CR bidirectional applanation tonometer (IOPcc – corneal-compensated IOP, IOPg – IOP close to Goldmann measurement). Then, several measurements were taken with a contact tonometer in the supine position. Results Before prescribing therapy, IOPcc, IOPg, and Icare were 25.4 ± 3.2, 25.7 ± 2.3, 22.9 ± 3.4 mmHg, respectively. In the supine position, Icare values ​​were 23.7 ± 3.3 and 24 ± 3.3 mmHg, respectively. In repeated measurements in the sitting position, IOPcc, IOPg, and Icare were 25.4 ± 3.2, 25.7 ± 2.4, and 22.3 ± 3.4 mmHg. After 1 month of therapy with a prostaglandin analogue, the following results were obtained: IOPcc, IOPg, and Icare decreased to 18.2 ± 2.7, 18.2 ± 1.8, and 16.6 ± 2.5 mmHg, respectively. In the supine position, Icare data were 17.3 ± 2.8 and 17.2 ± 2.7 mmHg, respectively. In repeated measurements in the sitting position, IOPcc, IOPg, and Icare reached 18 ± 2.3, 18.4 ± 1.8, and 16.2 ± 2.5 mmHg. respectively. Fluctuations in IOP with changes in body position were 0.83 ± 1.04 mm Hg at the initial examination, and 0.77 ± 1.41 mm Hg at the repeat examination. Conclusion The use of prostaglandin analogues as initial monotherapy for glaucoma allows minimizing fluctuations in IOP with changes in body position [4, 5]. Key words: glaucoma; intraocular pressure; prostaglandin analogues