Meta analysis of comparison of central corneal thickness measurement between Pentacam and A-scan in normal people / 中华实验眼科杂志

ABSTRACT

Background Central corneal thickness (CCT) is one of important parameters of the anterior eye segment.It plays a very important part in corneal refractive surgery and diagnosis of glaucoma.Contacted A-scan remains the gold standard for CCT measurement.Ophthalmologists are trying to look for a more convenient and noncontacted instrument to take place of contacted A-scan for CCT measurement.Objective This system analysis was to evaluate the difference between Pentacam and A-scan in CCT measurement.Methods A systematic literature retrieval was conducted from the MEDLINE,EMbase,Google Scholar,CBM disc and CNKI database with the limitation of publishing time from January 2005 to May 2011.The literature text was limited to the comparison of the CCT values measured by Pentacam and A-scan.The statistical analysis was performed using RevMan 5.1.0 software.Sensitive analysis was carried out and the publishing bias was analyzed using inverted funnel plot.Results A total of 26 studies met the requirement were included in this Meta-analysis with the 12 pieces of Chinese article and 14 pieces of English article,with the total eyes 3677.Heterogeneity was found anmong included studies (P =0.0003,I2 =56％) and random effects model was used.The differential value of CCT derived by Pentacam and A-scan was 1.74 μm,and no significant difference was found between Pentacam and A-scan (WMD =1.74,95％ CI-0.69-4.16,P＞0.05).Fixed effects model was used to exclude the studies with the sample more than 100 eyes as the sensitive analysis.When fixed effect model was used,CCT by Pentacam was 2.73 μm more than A-scan,showing an insignificantly clinical difference.When studies with a sample more than 100 eyes were excluded,the CCT value by Pentacam was 2.64 μm more than A-scan,without clinically significant difference between them.No obvious publishing bias was seen in the included literature.Conclusions The difference between Pentacam and A-scan in CCT measurement is less and could be ignored.