Clinical measurement of anterior chamber depth and lens thickness in myopic eyes with ultrasound and pentacam scheinpflug system

Abstract

Objective Anterior chamber depth （ACD） and lens thickness（LT） measurement gives important details in cataract or glaucoma stlrgery. And ACD is also strictly required in refractive surgery, such as excimer laser photorefractive keratectomy or phakic anterior ehamber lens implant. This investigation was to assess the accuracy of ultrasound and Pentaeam scheinpflug imaging system measuring ACD,LT in myopic eyes. Methods Thirty-eight eyes of 38 subjects aged 18 -28 years underwent non-contact tonometry, autorefraction and subjective refraction examination. After accommodative paralysis, ACD and LT from 38 right eyes were measured with scheimplug imaging system（Pentacam） and A sonography. Results The ACD value measured by Pentacam and A sonography was（ 3.33± 0. 24 ）mm and（ 3.81±0.24） ram, respectively, indicating a significant difference between the results of these two methods （ P 〈 0.01 ） and a positive linear correlation between them （ r = 0. 967, P 〈 0.01 ）. The LT value measured by Pentacam and A sonography was（3.34±0. 26） mm and（3.54±0. 17） mm respectively with the significant difference （ P 〈0.01 ） and a significant linear correlation between these two outcomes （ r =0. 815 ,P 〈0.01 ）. The difference in LT between the two methods was higher with the increase of diopter of refractive error, Conclusion Pentacam,as a new 3-dimensional mathematical model of the anterior segment, presents some different results from A sonography in the measurement of ACD and LT. Enough consideration should be payed to clinical evaluation of these results. Key words: Pentacam; anterior chamher depth; lens thickness; ultrasonography