This study aimed to examine the effect of Tiotropium, which is used in the treatment of COPD, on eye symptoms.The study was conducted prospectively. Patients were examined in three groups. Thirty-six patients were included in each group 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.

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.

This study is the first research that investigate the effects of Tiotropium on anterior chamber parameters, pupil diameters, and intraocular pressure in COPD treatment.

Inclusion Criteria:

1. Clinical diagnosis of COPD
2. Not receiving any COPD treatment
3. Receiving only 18 mcg Tiotropium treatment
4. With written consent

Exclusion Criteria:

1. Patients under 18 years of age 2. Pregnant women 3. Without written consent 4. Receiving the following medications: 4a. Inhaled and/or systemic steroids 4b. Long-acting inhaled beta-2 agonists 4c. Combined long-acting beta-2 agonists and long-acting anticholinergics 4d. Topical medication

5. Patients with the following comorbidities 5a. Glaucoma 5b. Cataract 5c. Hypertension 5d. Diabetes Mellitus 5e. Patients had previously undergone eyelid, refractive, or intraocular surgery, those with corneal diseases altering the corneal surface

6. Patients receiving topical medications for chronic eye diseases 7. Patients receiving medications for diabetes mellitus 8. Patients receiving medications for hypertension 8. Patients those using contact lenses

Three groups were formed for the study. 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 handhaler Tiotropium 18 mcg. 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.