Multi-center Clinical Trial on Corneal Morphology Analysis in Chinese Population

Based on the corneal morphometry instrumentation Oculus Pentacam, which is commonly used before and after clinical refractive surgery, we will collect the corneal morphological and biologic parameters of the population under refractive surgery screening in refractive surgery centers around the country, and construct corneal morphology database in different living areas of Chinese people. Based on this, compared with the suspected keratoconus and keratoconus population, the screening criteria and reference standards accord with the characteristics of keratoconus of Chinese ethnic will be achieved.

Study Overview

• Status: Unknown
• Conditions: Cornea
• Intervention / Treatment: Device: Scheimpflug tomography system (Pentacam) measurement

Detailed Description

The safety of refractive surgery has always been the focus of attention, keratoconus screening is the most important part for the preoperative examination of refractive surgery. Favorable tools and appropriate indicators are the premise of fast and accurate screening, and the corneal morphology from various regions of China have various characteristics, the use of uniform standards developed by foreign screening will always induce a lot of problems, for example, the differences of cornea morphological features between European and American ethnic and Chinese race, as well as the corneal morphometric indicators between various regions of China, will cause varying degrees of false-positive or false-negative screening results. Based on this, in order to further improve the safety of refractive surgery effectively and to obtain the effective and accurate screening of suspected keratoconus population, this study will be conducted to collect the corneal morphological characteristics database of Chinese people from all over the country, and to develop a database of Chinese ethnographic characteristics for screening keratoconus indicators and reference valuable to guide clinical screening and surgical design.

• Study Type: Observational
• Enrollment (Anticipated): 50000

Contacts and Locations

Study Locations

• China
  • Tianjin, China
    • Recruiting
    • Tianjin Eye Hospital
    • Contact: Yan Wang, director; Phone Number: +86-02227305083; Email: wangyan7143@vip.sina.com

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 14 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Chinese population of different nation from several provinces,including Jilin, Xi'an, Yunnan, Wuhan,etc.

Description

Inclusion Criteria:

• No less than 18 years old, in good health, have no active disease in the body and eye, have permanent resident status and have lived in the local area for at least 5 years (please mark the nation).

Exclusion Criteria:

• Eye diseases, glaucoma, ocular hypertension, glaucoma patients with normal pressure, fundus lesions, ptosis and other eyelid abnormalities.

Study Plan

How is the study designed?

Design Details

• Observational Models: Case-Crossover
• Time Perspectives: Cross-Sectional

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

Chinese population; Chinese population of different nation from several provinces.

Device: Scheimpflug tomography system (Pentacam) measurement; The Scheimpflug tomography system (Pentacam,Oculus GmbH, Wetzlar, Germany) is a rotating Scheimpflug camera that measures 138,000 true elevation points to compute corneal topography. Patients were asked to blink twice and then look at the fixation device. Image acquisition was a 2-second scan of 50 rotational Scheimpflug images through the corneal sighting point, the point where the ray of light from the fovea to the fixation device crossed the cornea. All measurements were performed just after a blink to minimize the effect of tear film alteration on the data. Acceptable maps had at least 10.0 mm of corneal coverage with no extrapolated data in the central 9.0 mm zone.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
corneal thickness	preoperative

Secondary Outcome Measures

Outcome Measure	Time Frame
corneal curvature measured by the Pentacam system	preoperative
coma aberration measured by the Pentacam system	preoperative
aspherical index measured by the Pentacam system	preoperative
spherical aberration measured by the Pentacam system	preoperative
corrected distance visual acuity	preoperative
uncorrected distance visual acuity	preoperative
refractive diopter	preoperative
corneal volume measured by the Pentacam system	preoperative
kapple angle measured by the Pentacam system	preoperative
introcular pressure	preoperative
corneal diameter measured by the Pentacam system	preoperative
anterior chamber depth measured by the Pentacam system	preoperative
anterior chamber angle measured by the Pentacam system	preoperative

Collaborators and Investigators

• Sponsor: Tianjin Eye Hospital
• Collaborators: Gansu Provincial Hospital; Health Science Center of Xi'an Jiaotong University; Xinjiang Medical University; Wuhan General Hospital of Guangzhou Military Command; Second People's Hospital of Yunnan Province; Jilin University
• Investigators: Study Director: Yan Wang, director, Tianjin Eye Hospital; Principal Investigator: Xiaoyu li, Second People's Hospital of Yunnan Province; Principal Investigator: Yan Zhang, Jilin University; Principal Investigator: Jun Yang, Gansu Provincial Hospital; Principal Investigator: Jing Li, Health Science Center of Xi'an Jiaotong University; Principal Investigator: Xianglong Yi, Xinjiang Medical University; Principal Investigator: Zhengwei Shen, Wuhan General Hospital of Guangzhou Military Command

Publications and helpful links

General Publications

• Silverman RH, Urs R, RoyChoudhury A, Archer TJ, Gobbe M, Reinstein DZ. Combined tomography and epithelial thickness mapping for diagnosis of keratoconus. Eur J Ophthalmol. 2017 Mar 10;27(2):129-134. doi: 10.5301/ejo.5000850. Epub 2016 Aug 8.
• Chan TCY, Biswas S, Yu M, Jhanji V. Comparison of corneal measurements in keratoconus using swept-source optical coherence tomography and combined Placido-Scheimpflug imaging. Acta Ophthalmol. 2017 Sep;95(6):e486-e494. doi: 10.1111/aos.13298. Epub 2016 Nov 2.
• Patrao LF, Canedo AL, Azevedo JL, Correa R, Ambrosio R Jr. Differentiation of mild keratoconus from corneal warpage according to topographic inferior steepening based on corneal tomography data. Arq Bras Oftalmol. 2016 Jul-Aug;79(4):264-7. doi: 10.5935/0004-2749.20160075.
• Naderan M, Rajabi MT, Zarrinbakhsh P, Farjadnia M. Is keratoconus more severe in pediatric population? Int Ophthalmol. 2017 Oct;37(5):1169-1173. doi: 10.1007/s10792-016-0382-5. Epub 2016 Oct 25.
• Ma J, Zhao L, Yang Y, Yun D, Yu-Wai-Man P, Zhu Y, Chen C, Li JO, Li M, Zhang Y, Cui T, Meng X, Zhang L, Zhang J, Song Y, Lei Y, Liu J, Huangfu X, Jiang L, Cai J, Wu H, Shang L, Wen D, Yi X, Zhang Y, Li X, Xiao J, He R, Yang Y, Yang J, Cheng GPM, Bai J, Zhong X, Guo H, Yan P, Wang Y, Lin H. Associations Between Regional Environment and Cornea-Related Morphology of the Eye in Young Adults: A Large-Scale Multicenter Cross-Sectional Study. Invest Ophthalmol Vis Sci. 2021 Feb 1;62(2):35. doi: 10.1167/iovs.62.2.35.

Helpful Links

• Combined tomography and epithelial thickness mapping for diagnosis of keratoconus.
• Comparison of corneal measurements in keratoconus using swept-source optical coherence tomography and combined Placido-Scheimpflug imaging
• Differentiation of mild keratoconus from corneal warpage according to topographic inferior steepening based on corneal tomography data
• Is keratoconus more severe in pediatric population?

Study record dates

Study Major Dates

• Study Start: November 1, 2015
• Primary Completion (Anticipated): August 1, 2019
• Study Completion (Anticipated): December 1, 2019

Study Registration Dates

• First Submitted: December 28, 2016
• First Submitted That Met QC Criteria: January 3, 2017
• First Posted (Estimate): January 5, 2017

Study Record Updates

• Last Update Posted (Actual): May 4, 2018
• Last Update Submitted That Met QC Criteria: May 3, 2018
• Last Verified: May 1, 2018

More Information

Terms related to this study

• Keywords: Chinese population; corneal curvature; higher order aberrations; corneal morphology; corneal thickness
• Other Study ID Numbers: Tianjin EH-pentacam

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No