An observational study in Cataract, sponsored by Peking University Third Hospital. Not yet recruiting at 1 site in China. Per ClinicalTrials.gov, last updated 2023-11-28.
Sponsored by Peking University Third Hospital · Observational
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.
1,701 studies on the registry are indexed under Cataract; 230 are open to participants now.
This study's planned enrollment of 11,000 is above the median of 81 across 484 observational studies indexed under Cataract.
Browse Cataract studies →Peking University Third Hospital is the lead sponsor of 735 studies on the registry; 262 are open to participants now.
Counted across the registry records on this site, refreshed daily.
All the patients who underwent cataract surgery in the Department of Ophthalmology, Peking University Third Hospital from January 2019 to May 2023.
Exclusion Criteria:
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 The Barrett toric calculator uses an unpublished mathematical prediction method of TCA based on anterior corneal measurements.
Also known as: the Abulafia-Koch formula, the Barrett toric calculator
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
Plan to share: No
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This study is not yet recruiting, as verified in Nov 2023. You cannot join it, but the record below documents what was studied.
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Peking University Third Hospital