Comparison of Measurement of Anterior Segment Parameters Between Scheimpflug Camera and Ultrasound Biomicroscopy

PURPOSE: To evaluate the clinical reliability of Pentacam(R) by comparing anterior chamber parameters measured by Oculus Pentacam system (Oculus Inc., Germany) and Hi-scan ultrasound biomicroscopy (OPTIKON 2000, Rome, Italy) in primary angle closure (PAC) and normal patients. METHODS: A prospective study was performed from June 2006 to January 2007. Fifty-one eyes in 26 primary angle-closure patients and 39 eyes in 20 normal control patients, for a total of 90 eyes of 46 patients were recruited from glaucoma out-patient clinics. The correlation and agreement of both measurements of anterior chamber depth and anterior chamber angle measured by UBM and Pentacam(R) were calculated. Sensitivity and specificity of each tool were also compared and the diagnostic value of angle closure was examined. RESULTS: Anterior chamber depth measured by UBM and Pentacam(R) showed strong correlation in the normal control group (r=0.821) and PAC group (r=0.957). Anterior chamber angle showed moderate correlation in the normal control group (r=0.523) and PAC group (r=0.456) while good agreement was also observed. In diagnosing angle closure, anterior chamber measurements appear similar in UBM and Pentacam(R) using the ROC curve (AUC of UBM, 0.942; AUC of Pentacam(R), 0.931). CONCLUSIONS: Pentacam(R) shows high to moderate correlation of anterior chamber measurements and good agreement compared with UBM. Pentacam(R) shows similar ability in diagnosing angle closure compared with UBM and thus is expected to be a good tool in diagnosing angle closure.

Wavefront and Visual Function Analysis After Aspherical and Spherical Intraocular Lenses Implantation

PURPOSE: To compare postoperative wavefront aberration and visual functions between aspherical Tecnis Z9003, a new acrylic aspheric intraocular lens (IOL), and spherical AcrySof SA60AT IOL. METHODS: Fifty patients (56 eyes) who underwent cataract extraction and were implanted with spherical or aspherical IOLs were randomly evaluated by wavefront analysis, including an examination of spherical aberration and higher-order aberrations using two different types of aberrometers (ray tracing and automatic retinoscope), manifested refraction, a contrast sensitivity test, and modulation transfer function (MTF), three months after surgery. RESULT: There were no statistically significant differences of spherical equivalent and best-corrected visual acuity between the two different IOL groups. However, the aspherical IOL group showed less spherical aberration and better contrast sensitivity and MTF than the spherical IOL group. CONCLUSIONS: Tecnis Z9003 could compensate for positive spherical aberrations of the cornea and improve contrast sensitivity and MTF, thereby improving visual function.