Refractory Outcomes after Cataract Surgery in Acute Primary Angle-closure Glaucoma Patients Treated with Laser Iridotomy

PURPOSE: To analyze the accuracy of ocular biometry and prediction of postoperative refraction after cataract surgery in acute primary angle-closure glaucoma (ACG) patients treated with laser iridotomy (LI). METHODS: We retrospectively reviewed the medical records of 44 patients who underwent cataract surgery after LI due to ACG (ACG group), and 37 patients who underwent cataract surgery without ocular disease other than cataract (control group) from January 2015 to May 2018. An Acrysof® single piece (SN60WF) was used as the intraocular lens. We performed preoperative ocular biometry and intraocular lens power calculations using AL-Scan®. The accuracy of the postoperative refractive power prediction was analyzed according to the anterior chamber depth (ACD) and axial length (AL). RESULTS: The preoperative ACD was 2.29 ± 0.32 mm in the ACG group and 3.15 ± 0.27 mm in the control group (p 2.31 mm in the ACG group (0.27 ± 0.20 D) and control group (0.27 ± 0.20 D). There was no significant difference in the mean absoluter error between each formula in patients with an AL of 22.1 mm in the ACG and control groups. CONCLUSIONS: Among patients treated with LI due to ACG, those patients with an ACD > 2.31 mm showed no difference in refractory prediction compared to the control group. However, in patients with an ACD < 2.30 mm, the refractory prediction may be inaccurate when using the Haigis formula, a fourth-generation formula that takes into account the ACD.

Comparative Efficacy of the New Optical Biometer on Intraocular Lens Power Calculation (AL-Scan versus IOLMaster)

PURPOSE: To evaluate the agreement in axial length (AL), keratometry, and anterior chamber depth measurements between AL-Scan and IOLMaster biometers and to compare the efficacy of the AL-Scan on intraocular lens (IOL) power calculations and refractive outcomes with those obtained by the IOLMaster. METHODS: Medical records of 48 eyes from 48 patients who underwent uneventful phacoemulsification and IOL insertion were retrospectively reviewed. One of the two types of monofocal aspheric IOLs were implanted (Tecnis ZCB00 [n = 34] or CT Asphina 509M [n = 14]). Two different partial coherence interferometers measured and compared AL, keratometry (2.4 mm), anterior chamber depth, and IOL power calculations with SRK/T, Hoffer Q, Holladay2, and Haigis formulas. The difference between expected and actual final refractive error was compared as refractive mean error (ME), refractive mean absolute error (MAE), and median absolute error (MedAE). RESULTS: AL measured by the AL-Scan was shorter than that measured by the IOLMaster (p = 0.029). The IOL power of Tecnis did not differ between the four formulas; however, the Asphina measurement calculated using Hoffer Q for the AL-Scan was lower (0.28 diopters, p = 0.015) than that calculated by the IOLMaster. There were no statistically significant differences between the calculations by MAE and MedAE for the four formulas in either IOL. In SRK/T, ME in Tecnis-inserted eyes measured by AL-Scan showed a tendency toward myopia (p = 0.032). CONCLUSIONS: Measurement by AL-Scan provides reliable biometry data and power calculations compared to the IOLMaster; however, refractive outcomes of Tecnis-inserted eyes by AL-Scan calculated using SRK/T can show a slight myopic tendency.

Comparison of Ocular Biometry Measurements Using A-Scan Ultrasound and Two Types of Partial Coherence Interferometers

PURPOSE: To compare the measurement results of 3 ocular biometry devices, A-scan ultrasound and two types of partial coherence interferometers in normal and cataractous eyes. METHODS: This study included 42 normal eyes and 40 cataractous eye. Axial length and anterior chamber were measured using three ocular biometry measurements, ultrasonography (HiScan®, Optikon 2000, Rome, Italy), IOL Master® (Carl Zeiss, Jena, Germany), and AL-scan® (Nidek, Gamagori, Japan), and mean corneal curvature and corneal diameter were measured using two partial coherence interferometers. The results were compared in each group. RESULTS: Significant differences in measurements existed among the 3 ocular biometry devices (A-scan ultrasound, IOL Master® and AL-scan®) in normal eyes (p < 0.001) and cataractous eyes (p = 0.034). However, the measurements were not significantly different between the 2 partial coherence interferometers (IOL Master® and AL-scan®) in both groups. We confirmed lower agreement among the 3 ocular biometry devices in cataractous eyes compared with normal eyes in terms of a larger range of 95% agreement and error in cataractous eyes. CONCLUSIONS: Significant differences in measurements were observed when using the 3 ocular biometry devices in both normal and cataractous eyes. Because of low agreements between ocular biometry devices in cataractous eyes, complementing the measurements between ocular biometry devices is necessary when measuring cataractous eyes.

Comparative Analysis of Corneal Refractive Power Measured with AL-Scan(R), Autokeratometer, and Pentacam(R)

PURPOSE: To investigate clinical availability of AL-Scan(TM) (Nidek, Gamagori, Japan) by comparing corneal refractive power with AL-Scan(TM), Autokeratometer(TM) (Topcon KR-1, Tokyo, Japan) and Pentacam(TM) (Oculus, Wetzlar, Germany) devices. METHODS: Seventy-one patients (142 eyes) who visited our hospital for refractive surgery were tested using AL-Scan(R), Autokeratometer and Pentacam(R) and corneal refractive power was compared among devices. RESULTS: When comparing measurements with AL-Scan(R), Autokeratometer and Pentacam(R), the mean corneal refractive power was 43.37 +/- 1.32 D (2.4 mm zone), 43.35 +/- 1.32 D (3.3 mm zone), 43.36 +/- 1.35 D, and 43.35 +/- 1.36 D respectively and showed no significant differences. Corneal refractive power had strongly positive linear correlation (p < 0.001) and Bland-Altman plots showed high degree of agreement among AL-Scan(R), Autokeratometer and Pentacam(R) devices. CONCLUSIONS: Because measuring ocular biometry with AL-Scan(R) including axial length, intraocular lens power calculation and topography simultaneously is possible, clinical use is convenient. Corneal refractive power was not different when compared with autokeratometer and Pentacam(R) devices, thus, AL-Scan(R) can be used in the clinical environment.

Measurement Comparison of Anterior Segment Parameters between AL-Scan(R) and Pentacam(R)

PURPOSE: To investigate the clinical availability of AL-Scan(R) (Nidek, GAMAGORI, Japan) by comparing anterior segment parameters measured with AL-Scan(R) and Pentacam(R) (Oculus, Wetzlar, Germany). METHODS: Seventy-three patients (117 eyes) who received refractive surgery at our hospital were tested with AL-Scan(R) and Pentacam(R). We compared measurements including anterior chamber depth, central corneal thickness, white-to-white, and corneal curvature. RESULTS: When comparing measurements obtained with AL-Scan(R) and Pentacam(R), the anterior chamber depth (p < 0.001), central corneal thickness (p < 0.001) and 2.4 mm zone K value (p = 0.038) showed significant differences; the white-to-white (p = 0.348) and 3.3 mm zone K value (p = 0.429) showed no significant differences. All AL-Scan(R) and Pentacam(R) parameters had a strong positive linear correlation (p < 0.001). The Bland-Altman plots showed a high degree of agreement between AL-Scan(R) and Pentacam(R) in all parameters except for anterior chamber depth. CONCLUSIONS: AL-Scan(R) is convenient to use clinically because simultaneous measurements of ocular biometry including axial length, intraocular lens power, and topography are possible. However, because differences in some anterior segment parameters exist when compared with Pentacam(R), measurements with AL-Scan(R) may require comparisons with other instruments.

Accuracy of Ocular Biometry and Postoperative Refraction in Cataract Patients with AL-Scan(R)

PURPOSE: To compare the axial lengths, anterior chamber depths, and keratometric measurements and to predict postoperative refractions of AL-Scan(R), IOL master(R), and ultrasound. METHODS: A total of 40 eyes in 30 patients who received cataract surgery were included in the present study. The axial length, anterior chamber depth, and keratometry were measured by 2 types of partial coherence interferometry (AL-Scan(R) and IOL master(R)) and ultrasound. The SRK/T formula was used to calculate IOL power, and the predictive error which subtracts predictive refraction from postoperative refraction was compared among the ocular biometry devices. RESULTS: Axial lengths were 23.08 +/- 0.62 mm, 23.09 +/- 0.62 mm, and 22.99 +/- 0.62 mm measured by AL scan(R), IOL master(R), and ultrasound, respectively. Axial length measured by ultrasound was statistically significantly shorter than AL scan(R) and IOL master(R) (p < 0.001, p < 0.001, respectively). The anterior chamber depth and keratometry were 3.11 +/- 0.06 mm and 44.82 +/- 1.34 D measured by AL scan(R), and 3.13 +/- 0.06 mm and 44.85 +/- 1.26 D measured by IOL master(R), respectively. The differences of anterior chamber depth and keratometry between the 2 devices were not statistically significant (p = 0.226, p = 0.331, respectively). The mean absolute prediction errors were 0.44 +/- 0.35 D, 0.40 +/- 0.34 D, and 0.39 +/- 0.30 D in AL-Scan(R), IOL master(R) and ultrasound, respectively, and were not statistically significantly different (p = 0.843, p = 0.847, p = 1.000, respectively). CONCLUSIONS: The ocular biometric measurements and prediction of postoperative refraction using AL-Scan(R) were as accurate as IOL master(R) and ultrasound.