Effect of Dry Eye Treatment on Corneal Astigmatism Measurements

Jin Yang400 enrolled

Overview

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.

Study Type

INTERVENTIONAL

Allocation

NON_RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Enrollment

400

Conditions

Dry Eye Cataract

Eligibility

Sex: ALL

Medical Language ↔ Plain English

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

Outcomes

Primary Outcomes

Interdevice Agreement of Corneal Astigmatism Measurements

Interdevice agreement of corneal astigmatism measurements among IOLMaster 700, Pentacam AXL, and iTrace Prime will be assessed using Bland-Altman analysis. Pairwise comparisons will be performed for IOLMaster 700 versus Pentacam AXL, IOLMaster 700 versus iTrace Prime, and Pentacam AXL versus iTrace Prime. The main parameters include keratometric corneal astigmatism, total corneal astigmatism, and their vector components J0 and J45. The mean difference and 95% limits of agreement will be calculated.

Time frame: Baseline and 2 weeks after ocular surface treatment in the dry eye disease arm.

Test-Retest Repeatability of Corneal Astigmatism Measurements

Test-retest repeatability of corneal astigmatism measurements obtained using IOLMaster 700, Pentacam AXL, and iTrace Prime will be evaluated using three consecutive valid measurements from each device. The main parameters include keratometric corneal astigmatism, total corneal astigmatism, and their vector components J0 and J45. Repeatability will be assessed using within-subject standard deviation, test-retest repeatability calculated as 2.77 times the within-subject standard deviation, and intraclass correlation coefficient with 95% confidence intervals.