Examination of the Effect of Handhaler Tiotropium, a Long-acting Anticholinergic, on Anterior Chamber Parameters

Chronic obstructive pulmonary disease (COPD) is a persistent, chronic inflammatory disease of the lungs. Tiotropium, used in the treatment of COPD, is a muscarinic receptor antagonist that provides long-acting bronchodilation. In this study the researchers aimed to investigate the effects of Tiotropium on eye anterior chamber parameters.

The study was conducted prospectively between October 2023 and April 2024 after obtaining local Ethics Committee approval (Giresun EAH KEAK 2023/180 and 9.10.2023/02). Patients diagnosed with COPD and included in Group A according to the GOLD 2024 guidelines, along with healthy volunteers, were enrolled. Patients diagnosed with COPD, with mMRC scale 0-1, CAT score <10, who had never experienced an exacerbation before or had a mild severity exacerbation once that not required hospitalization were considered as Group A. Patients were examined in three groups: Group 1 consisted of COPD patients not receiving treatment, Group 2 consisted of healthy volunteers for similar age and gender, and Group 3 consisted of COPD patients of the same age and gender with receiving Tiotropium 18 mcg Handihaler. A total of 108 patients, 36 patients in each group, were included in the study. Anterior chamber parameters, intraocular pressure values and photopic-mesopic pupil diameters were measured at the initial visit for Group 1 and Group 2 patients, and at the third month of treatment for Group 3 patients.

Anterior segment optical coherence tomography (AS-OCT) was used to measure anterior chamber and angle parameters, corneal topography was utilized to assess anterior chamber depth, pupil diameter measurements in mesopic and photopic conditions, and intraocular pressure (IOP) was calculated using Goldmann applanation tonometry. Each patient underwent a comprehensive ophthalmic evaluation, including testing of best-corrected visual acuity, slit-lamp biomicroscopy, and fundoscopic examination.

Corneal topography (Topcon Aladdin Corneal Topography, Japan) was used to evaluate anterior chamber depth and pupil diameter in mesopic and photopic conditions. Pupil diameters measured with corneal topography were obtained by the same researcher, using the same device, at the same times of day and under similar lighting conditions.

Intraocular pressure was measured using Goldman Applanation tonometry. All measurements were conducted by the same researcher around 10 a.m., using the same tonometer device, without any manipulation or negligible manipulation of the eyelids. Applanation was performed by rotating the dial on the Goldman tonometer previously set to 10 mm Hg. The procedure was repeated after one minute. If the difference between the first and second readings was greater than 2 mm Hg, a third reading was performed. The average of the data obtained from two readings was taken, and if a third reading was needed, the median was used instead.