Effect of Dry Eye Treatment on Corneal Astigmatism Measurements

Effect of Dry Eye and Ocular Surface Treatment on Agreement and Repeatability of Corneal Astigmatism Measurements Among Three Devices

This prospective single-center study evaluates the effect of dry eye disease and short-term ocular surface treatment on the agreement and repeatability of corneal astigmatism measurements in patients with age-related cataract. Participants undergoing preoperative cataract evaluation are classified into a control group or a dry eye disease group according to ocular surface symptoms and objective tear film findings.

All participants undergo ocular surface assessment and repeated corneal measurements using three commonly used devices: IOLMaster 700, Pentacam AXL, and iTrace Prime. Measurements include keratometric corneal astigmatism, total corneal astigmatism, and vector components of astigmatism. Patients with dry eye disease receive 0.3% sodium hyaluronate eye drops four times daily for 2 weeks, after which ocular surface assessment and device measurements are repeated.

The primary objective is to determine whether dry eye disease reduces interdevice agreement and test-retest repeatability of corneal astigmatism measurements, and whether short-term ocular surface treatment improves measurement stability. Interdevice agreement is assessed using Bland-Altman analysis, and repeatability is evaluated using within-subject standard deviation, test-retest repeatability, and intraclass correlation coefficient.

Inclusion Criteria:

• Patients with age-related cataract undergoing preoperative ocular examination.
• Ability to complete ocular surface evaluation, including the Ocular Surface
• Disease Index questionnaire, non-invasive tear film break-up time, tear meniscus height, Schirmer test, and ocular surface staining.
• Ability to complete repeated corneal astigmatism measurements using IOLMaster 700, Pentacam AXL, and iTrace Prime.
• Ability to maintain stable fixation during device measurements. Provision of written informed consent.

Exclusion Criteria:

• Previous ocular surgery or ocular trauma.
• Corneal degeneration, corneal dystrophy, or other corneal diseases that could affect corneal measurements.
• Active corneal or conjunctival infection.
• Uveitis.
• Use of any topical eye drops within 24 hours before examination.
• Use of antiglaucoma medications.
• Contact lens wear within 1 month before examination.
• Previous or ongoing treatment for dry eye disease.
• Poor fixation during device measurements.
• Poor-quality measurements from any study device