Outcomes of toric intraocular lens realignment surgery done using slit-lamp method and wavefront aberrometry method

Purpose: To compare the slit?lamp method and wavefront aberrometry method based on outcomes of toric realignment surgeries. Settings: Tertiary care ophthalmic hospital. Design: Retrospective study. Methods: This study included all eyes undergoing toric intraocular lens (TIOL) realignment surgery between January 2019 and December 2021 for which TIOL axis assessment by slit?lamp method and wavefront aberrometry method was available. Data were retrieved from electronic medical records, and we documented demographics, uncorrected visual acuity (UCVA), subjective refraction, and TIOL axis by slit?lamp and wavefront aberrometry methods on postoperative day 1 and day 14. In patients with misalignment, TIOL was realigned to the original position in group 1 (27 patients) and to an axis based on calculations provided by wavefront aberrometer in group 2 (25 patients). Post?realignment surgery, UCVA, subjective refraction, and TIOL axis by slit?lamp and wavefront aberrometry methods were assessed and analyzed. Results: We analyzed 52 eyes and found that the mean preoperative misalignment with the slit?lamp method (44.9° ±20.0°) and wavefront aberrometry (47.1° ±19.5°) was similar. The corresponding degrees of misalignment post?TIOL repositioning surgeries were 5.2° ±5.2° (slit?lamp method) and 4.7° ±5.1° (wavefront aberrometry) (P = 0.615). Both groups showed significant improvement in median log of minimum angle of resolution (logMAR) UCVA and reduction in median refractive cylinder. Conclusions: Slit?lamp method is as good as wavefront aberrometer method to assess TIOL axis. Toric realignment surgery is found to be safe, and realigning TIOL based on either slit?lamp method or wavefront aberrometer method equally improved UCVA and decreased residual refractive cylinder.

Mesopic Pupillometry in Pre-LASIK Patients by a Placido-Disc Topographer and Hartmann-Shack Aberrometer

@#Introduction: Precise pupillometry is crucial to determine ablation optical zone (OZ) size selection in LASIK. Significant difference in the selection induces unwanted postoperative night visual disturbance. Placido-disc topographer and Hartmann-Shack aberrometer are commonly used in LASIK preoperative assessment. However, little is known on the precision and agreement of these devices in pupillometry. Hence, this study aimed to evaluate the precision (repeatability and reproducibility) and inter-device agreement of a Placido-disc topographer and Hartmann-Shack aberrometer in measuring mesopic pupil size in pre-LASIK patients. Methods: Mesopic pupillometry on 38 pre-LASIK patients were performed using both devices by two masked operators, on two separate sessions. Intra-session repeatability, inter-operator reproducibility and inter-device agreement were analysed. A disagreement value of ±0.5 mm and 95% limits of agreement (LoA) were determined. Results: Hartmann-Shack aberrometer demonstrated higher repeatability and reproducibility than Placido-disc topographer in mesopic pupillometry. Ninety-seven percent and all of Hartmann-Shack wavefront aberrometer pupillometry were within ±0.5 mm in repeated sessions and between the operators, respectively. The mesopic pupil size obtained from Placido-disc topographer was significantly larger than Hartmann-Shack aberrometer results (P = 0.02). The agreement between devices was low (LoA > ±1 mm) and only 53% of Placido-disc topographer pupillometry were within ±0.5 mm of Hartmann-Shack aberrometer pupillometry. Conclusion: Hartmann-Shack aberrometer has higher precision within sessions and between operators, and it provides smaller mesopic pupillometry than Placido-disc topographer. Precise mesopic pupillometry could assist refractive surgeons in choosing a correct ablation OZ size during LASIK surgery to improve postoperative outcome.

Evaluation of Optical Quality Parameters and Ocular Aberrations in Multifocal Intraocular Lens Implanted Eyes

PURPOSE: We investigated the correlations between optical quality parameters obtained from the double-pass system and ocular aberrations obtained from the ray-tracing aberrometer in multifocal intraocular lens (IOL) implanted eyes. MATERIALS AND METHODS: Twenty eyes from 20 patients were enrolled in this study. Modulation transfer function cutoff frequency, The Strehl ratio, objective scatter index, and objective pseudo-accommodation obtained from the double-pass system were compared with root mean square (RMS) total aberration, RMS higher-order aberration, and spherical aberration obtained from the ray-tracing aberrometer. Additionally, parameters of the double-pass system and ray-tracing aberrometer were compared with manifested refraction values and subjective visual acuity, respectively. RESULTS: There was no statistically significant correlation between optical quality parameters obtained from the double-pass system and ocular aberrations, except between the Strehl ratio and RMS total aberration (r=-0.566, p=0.018). No significant correlations were found between the parameters of both devices, and manifested refraction values or subjective visual acuity. CONCLUSION: Optical quality parameters, especially the Strehl ratio, in multifocal IOL implanted eyes were affected by RMS total aberration. Further studies based on accurate measurements of ocular aberrations and additional optical quality parameters are needed to delineate relationships between optical quality parameters and ocular aberrations in multifocal IOL implanted eyes.

The Efficacy of KR-1W Aberrometer in Assessing the Astigmatism after Toric Intraocular Lens Implantation

PURPOSE: To evaluate the efficacy of the KR-1W aberrometer in assessing the astigmatism and the achieved axis after AcrySof Toric intraocular lens (IOL) implantation. METHODS: Thirty-nine patients (48 eyes) that had undergone phacoemulsification and AcrySof Toric IOL implantation were included in the present study. At postoperative 1 month, ocular aberrations of all the eyes were measured using the KR-1W aberrometer before mydriasis and the achieved axis of AcrySof Toric IOL was measured by slit lamp examination after mydriasis. The achieved axis measured by slit lamp examination and the astigmatism of the implanted AcrySof Toric IOL were compared with the KR-1W. RESULTS: The mean achieved lens axis after mydriasis measured by slit lamp examination and KR-1W was 86.43 +/- 47.49 degrees and 88.93 +/- 41.22 degrees, respectively. The correlation coefficient of the 2 methods was 0.992 (p < 0.001). The measured astigmatism according to the AcrySof Toric IOL model was 1.11 +/- 0.47D in SN60T3, 1.71 +/- 0.51D in SN60T4, and 3.32 +/- 0.78D in SN60T5. CONCLUSIONS: Without the need to directly evaluate the axis of implanted Toric IOL after mydriasis, the achieved lens axis can be measured by the KR-1W without mydriasis. The AcrySof Toric IOL model could be assessed by the KR-1W without information about the AcrySof Toric IOL model.

Comparison of the Refractive Error Measurement Using Different Methods in Wavefront-Guided LASEK

PURPOSE: To predict the accuracy of preoperative refractive error measurement methods in wavefront-guided laser-assisted subepithelial keratectomy (LASEK) surgery and to formulate a nomogram for satisfactory surgical results. METHODS: The medical records of 30 patients (57 eyes) who had undergone wavefront-guided LASEK were reviewed. The ideal surgical ablation amount was defined as the sum of the real surgical ablation amount and the remaining refractive errors. Comparison between the ideal surgical ablation amount and preoperative refractive errors was made using autorefraction, manifest refraction, cycloplegic refraction, postcycloplegic refraction, wavescan, and iTrace aberrometer measurements. RESULTS: The refractive errors measured by the postcycloplegic refraction showed the closest relation with the ideal surgical amount, and the nomogram based on this refraction correlated statistically significantly with the ideal surgical ablation amount. The refractive error using the wavescan also showed more accurate refractive measurements than the autorefractor and iTrace aberrometer. CONCLUSIONS: Accurate manifest refraction immediately before surgery is the most important in determining the ablation amount. Additionally, the refractive errors measured with the wavescan, which is an aberrometer used for wavefront-guided LASEK, showed a minimal amount of errors. After reviewing the results, the nomogram based on these 2 methods can be concluded to possibly contribute to an increase in the accuracy of surgery.

Comparison of Aberrations in Korean Normal Eyes Measured With Two Different Aberrometers

PURPOSE: To compare ocular higher order aberrations measured by two different aberrometers in a sample of normal eyes. METHODS: We included 41 normal eyes of Koreans in this study. Ocular aberration data were obtained through three measurements per eye using Zywave and OPD-Scan devices. Spherical equivalent and higher order aberrations calculated in the central 6 mm zone and expressed as root mean square (RMS) values were analyzed. RESULTS: A comparison of measurements between the Zywave and OPD-Scan devices demonstrated no statistically significant differences in the RMS values of total higher order aberration (p=0.11), but significant differences were detected in the RMS values of total spherical aberration, total coma and total trefoil (p<0.01). CONCLUSIONS: The two different aberrometers that we tested are suitable for taking repeated measurements and are internally consistent, but not interchangeable.

Comparison of WaveScan Aberrometer Refraction to Subjective Manifest Refraction and Autorefractor

PURPOSE:To compare the accuracy of myopic refraction using an aberrometer (WaveScan, Visx, Santa Clara, CA, USA) with manifest refraction using retinoscopy and an autorefractor. METHODS: The medical records of 200 eyes in 100 patients who visited our clinic from February 2005 to February 2007 for refractive surgery were reviewed retrospectively. We compared the refractive errors obtained using an aberrometer, retinoscopy, and an autorefractor (KR-7100, Topcon, Tokyo, Japan). All of the measured refractive errors were converted to power vectors for statistical analysis. The power vectors consisted of the M vector (M), J0 vector (J0), and J45 vector (J45). RESULTS: The mean sphere was -4.75 diopters (D) and the mean cylinder was -0.66D with retinoscopy. Power vectors of the aberrometer (PVw) were highly correlated with power vectors of retinoscopy (PVr) and the autrorefractor (PVa). The correlation coefficients (R2) between PVw and PVr were 0.960 (M), 0.852 (J0), and 0.679 (J45) and the correlation coefficients between PVw and PVr were 0.963 (M), 0.685 (J0), and 0.516 (J45). Mean differences were -0.247+/-0.412D (M), 0.034+/-0.120D (J0), and -0.017+/-1.07D (J45) between PVw and PVr, and were -0.068+/-0.403D (M), -0.055+/-0.194D (J0), and -0.052+/-0.165D (J45) between PVw and PVa. CONCLUSIONS: The measurement of refractive errors using a WaveScan aberrometer seems to be reliable and accurate, although some myopic shift was observed.

A contralateral eye study comparing apodized diffrative and full diffrative lenses: wavefront analysis and distance and near uncorrected visual acuity

PURPOSE: To evaluate intraindividual visual acuity, wavefront errors and modulation transfer functions in patients implanted with two diffractive multifocal intraocular lenses. METHODS: This prospective study examined 40 eyes of 20 cataract patients who underwent phacoemulsification and implantation of a spherical multifocal ReSTOR intraocular lens in one eye and an aspheric Tecnis ZM900 multifocal intraocular lens in the other eye. The main outcome measures, over a 3-month follow-up period, were the uncorrected photopic distance and near visual acuity and the defocus curve. The visual acuity was converted to logMAR for statistical analysis and is presented in decimal scale. The wavefront error and modulation transfer function were also evaluated in both groups. RESULTS: At the 3-month postoperative visit, the mean photopic distance uncorrected visual acuity (UCVA) was 0.74 ± 0.20 in the ReSTOR group and 0.76 ± 0.22 in the Tecnis group (p=0.286). The mean near UCVA was 0.96 ± 0.10 in the ReSTOR group and 0.93 ± 0.14 in the Tecnis group (p=0.963). The binocular defocus curve showed measurements between the peaks better than 0.2 logMAR. The total aberration, higher-order aberration and coma aberration were not significantly different between the groups. The spherical aberration was significantly lower in the Tecnis group than in the ReSTOR group. (p=0.004). Both groups performed similarly for the modulation transfer function. CONCLUSION: The ReSTOR SN60D3 and Tecnis ZM 900 intraocular lenses provided similar photopic visual acuity at distance and near. The diffractive intraocular lenses studied provided a low value of coma and spherical aberrations, with the Tecnis intraocular lens having a statistically lower spherical aberration compared to the ReSTOR intraocular lens. In the 5 mm pupil diameter analyses, both intraocular lens groups showed similar modulation transfer functions.

Power Vector and Aberrations Using Corneal Topographer and Wavefront Aberrometer Before and After Pterygium Surgery

PURPOSE: To determine the power vector and aberrations before and after surgery for pterygium using a corneal topographer and a wavefront aberrometer. METHODS: The study group consisted of 34 eyes of 31 patients with pterygium, and were divided into two groups by pterygium size ( or = 3 mm, group II). Power vector and wavefront aberrations were evaluated using a corneal topographer (Oculus inc., Germany) and a wavefront aberrometer (LADARWAVE(R), Hartmann shack aberrometer, Alcon inc., US) at pre- and postoperative 1 week, 1 month, and 3 months. RESULTS: The preoperative blurring strength (B) and high order aberrations significantly decreased at postoperative 3 months in all groups (P or = 3 mm). To reduce aberrations and astigmatism effectively, we suggested surgical intervention in eyes with pterygia sized < 3.0 mm.

Clinical Comparison of Laser Ray Tracing Aberrometer and Shack-Hartmann Aberrometer

PURPOSE: To compare ocular aberrations measured with a laser ray tracing aberrometer (iTrace(R), Tracey technology) or a Shack-Hartmann aberrometer (Zywave(TM), Bausch & Lomb). METHODS: A total of 68 eyes were included in this study. After manifest refraction (MR) and pupil dilation, aberrations and phoroptor predicted refraction (PPR) were measured with the Zywave(TM) and iTrace(R) devices. The study group was subdivided into a more myopic group (-4.33 D). The root mean square (RMS) errors of the total high order, spherical, coma and 3rd~5th order aberrations were compared. RESULTS: The mean and SE of MR was -4.33+/-2.03 diopter (D), and that of the PPR was -4.20+/-2.13 D in iTrace(R) and -4.42+/-2.23 D in Zywave(TM). A paired-t test of the PPR and MR indicated that they were not statistically different. Zernike coefficients were expressed in the opposite sign in the 2nd and 4th order. The coma and spherical aberrations were larger in Zywave(TM). In a scattergram of each Zernike coefficient, the coefficient of determination (R2) was very low with higher order aberrations, with an exception for coma and spherical aberrations. The correlation of RMS error was greater in the less myopic group. CONCLUSIONS: Taking PPR values as a good reference of MR was a reliable method. For the HOA, only coma and spherical aberrations showed good correlations between Zywave(TM) and iTrace(R), and the correlations for HOA were decreased for the high myopic eyes.