The purpose of this study is to report the prevalence data for total corneal astigmatism (TCA) in cataract surgery candidates.
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.
Study Type
OBSERVATIONAL
Enrollment
11,000
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 The Barrett toric calculator uses an unpublished mathematical prediction method of TCA based on anterior corneal measurements.
Peking University Third Hospital
Beijing, Beijing Municipality, China
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.
Time frame: 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.
Time frame: 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The Barrett toric calculator uses an unpublished mathematical prediction method of TCA based on anterior corneal measurements.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.
Time frame: At Enrollment
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