Accuracy of Corneal Astigmatism in Different Region Modes

Study Overview
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Brief Summary
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To analyze the difference between measured total corneal astigmatism and actual corneal astigmatism under different region modes and optimize the region setting.

Official Title
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Accuracy of Corneal Astigmatism in Different Region Modes

Conditions
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Astigmatism, Cornea

Intervention / Treatment
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* Other: patients with corneal astigmatism


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age ≥ 18 years Patients who had received phacoemulsification surgery with or without implantation of toric IOL are with a certain amount of corneal astigmatism. Best corrected visual acuity ≥ 0.66 (20/30 Snellen) Exclusion Criteria: Corneal diseases or severe irregular astigmatism (e.g., pterygium, keratoconus), existence of corneal opacification; Ocular disease which may affect visual acuity (e.g., glaucoma, uveitis, retinal disease, pathologic myopia); History of ocular surgery or ocular trauma before this cataract surgery; Decentration of IOL > 0.3mm or tilt > 5° Implantation of multifocal IOL history of wearing of rigid contact lens within the past 4 weeks or soft contact lens within 1 week;

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| patients with corneal astigmatism<br>Patients who had received phacoemulsification surgery with or without implantation of toric IOL are with a certain amount of corneal astigmatism. | Other: patients with corneal astigmatism<br>* The total corneal astigmatism, anterior chamber depth, will be measured by a Scheimpflug tomographer. Pupil size will be measured by itrace device and MONCV3 device. Residual astigmatism will be tested by subjective refraction.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Vectorial difference | The vectorial difference between measured corneal astigmatism (under multiple different region mode settings) and actual corneal astigmatism. | ≥1 month after surgery | 
| pupil size | pupil size of patients in a bright environment measured by itrace device and MONCV3 device | ≥1 month after surgery | 
| pupil size 2 | pupil size of patients measured by Pentacam HR device | ≥1 month after surgery | 
| residual astigmatism | residual astigmatism tested by subjective refraction | ≥1 month after surgery | 
| total corneal astigmatism | Total corneal astigmatism measured by a scheimpflug tomographer under different region mode settings. | ≥1 month after surgery | 
| Anterior chamber depth | The distance between corneal apex and anterior surface of IOL measured by a scheimpflug tomographer | ≥1 month after surgery | 
| actual corneal astigmatism | actual corneal astigmatism is derived from residual astigmatism at corneal plane and cylindrical power of IOL at corneal plane through Holladay 2 formula. | ≥1 month after surgery | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Toric, Corneal Astigmatism, Scheimpflug, pupil size