A Comparative Study Of Corneal Horizontal Diameter Measured By Tthree Different Instruments

Objective:To compare the front section measurement evaluation system Pentacam HR,IOL Master 500,caliper three instrument measuring the diameter of the corneal level difference,and evaluates three kinds of instruments have problems eye intraocular lens crystals into(Implantable collamer lens,ICL)technique,the application of to select the most optimal ICL to implant diameter in order to avoid the occurrence of postoperative adverse events and make patients get better visual effect.Methords:this study is a prospective study,including 52 eyes of 27 patients who planned to undergo ICL V4 C implantation to correct ametropia in our hospital from January to June 2020.Before surgery,three instruments including Pentacam HR,IOL Master 500 and caliper were used to measure corneal horizontal diameter(WTW).The measured data were statistically analyzed to compare the differences and correlations between the measured results of the three instruments.The WTW values measured by Pentacam HR were input into the formula of the IOL manufacturer to calculate the diameter of ICL,and then the ICL was implanted.Postoperative parameters such as arch height and anterior chamber depth were examined by the anterior segmental measurement and evaluation system Pentacam HR.The optimal naked visual acuity,intraocular pressure,corneal endothelium count and arch height were observed 3 months after operation to evaluate the postoperative efficacy.Resuits: The mean corneal horizontal diameters measured by Pentacam HR,IOL Master and caliper were 11.64±0.43 mm,11.91±0.43 mm and11.59±0.45 mm,respectively.There was no statistical difference between Pentacam HR calipers and Pentacam HR calipers.The differences between IOL Master and Pentacam HR calipers were statistically significant(P < 0.05).Conclusion: The horizontal diameter of cornea measured by the three instruments can be used as a reference to each other.There was no significant difference in the measured values of horizontal corneal diameter between Pentacam HR and calipers,and they could be substituted for each other in clinical practice.However,IOL Master’s measured value is too large,so it is not recommended to directly apply its measured value to the calculation of ICL diameter,but the measured value can be used according to the corrected difference with Pentacam HR and caliper measurements.The post-operative arch height obtained from ICL diameter calculated on the basis of WTW measured by Pentacam HR is ideal,and Pentacam HR measurement and evaluation system is an objective instrument for non-contact measurement,with simple operation,good repeatability,high patient comfort and cooperation degree.Therefore,ICL diameter can be calculated according to WTW measured by Pentacam HR for clinical implantation.