Total Corneal Astigmatism Prevalence in Cataract Patients

Study Overview
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Brief Summary
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The purpose of this study is to report the prevalence data for total corneal astigmatism (TCA) in cataract surgery candidates.

Detailed Description
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The purpose of this retrospective study is to report the prevalence data for total corneal astigmatism (TCA) in cataract surgery candidates. Preoperative biometric data of all the patients who underwent cataract surgery in the Department of Ophthalmology, Peking University Third Hospital, from January 2019 to May 2023, were collected and analyzed. Data sets with incomplete biometric data were excluded.

Official Title
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Prevalence Data for Total Corneal Astigmatism in Cataract Surgery Candidates

Conditions
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Cataract

Intervention / Treatment
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* Diagnostic Test: IOLMaster 700


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients who underwent cataract surgery in the Department of Ophthalmology, Peking University Third Hospital from January 2019 to May 2023. Exclusion Criteria: Incomplete biometric data .
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

| Intervention/Treatment |
| --- |
|Diagnostic Test: IOLMaster 700|The IOLMaster 700, one of the most commonly used optical biometers for IOL power calculation, measures the anterior corneal surface radius using a telecentric keratometry. Additionally, it employs swept-source optical coherence tomography (SS-OCT) technology to simultaneously measures the posterior cornea surface radius and central corneal thickness (CCT). The AK formula, described by Abulafia et al., is a regression formula that calculates an estimated TCA using K astigmatism. The Barrett toric calculator uses an unpublished mathematical prediction method of TCA based on anterior corneal measurements.|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| total keratometric astigmatism | Total keratometry is calculated based on the anterior and posterior corneal surface radius and CCT using the thick lens formula with the actual indices of refractions for air (1.000), cornea (1.376), and aqueous (1.336) by IOLMaster 700. Total keratometric astigmatism is taken as the TCA measured by IOLMaster 700. | At Enrollment | 
| Abulafia-Koch formula total corneal astigmatism | The AK formula, described by Abulafia et al, is a regression formula that calculates an estimated TCA using K astigmatism. | At Enrollment | 
| Barrett toric calculator total corneal astigmatism | The Barrett toric calculator uses an unpublished mathematical prediction method of TCA based on anterior corneal measurements. AL, ACD, LT, WTW, and K data by IOLMaster 700 were input into the Barrett toric calculator. The target refraction, incision surgically induced astigmatism (SIA), and incision location were all set as 0. The output net astigmatism was recorded as TCA predicted by the Barrett toric calculator. | At Enrollment | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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cataract, astigmatism, prevalence