Comparison of the 1st Generation and 3rd Generation Wavefront-Guided LASIK for the Treatment of Myopia and Myopic Astigmatism.

Purpose: To compare refractive, visual, and patient-reported outcomes associated with a 1st generation wavefront-guided (WFG) treatment with those associated with a 3rd generation WFG treatment. Patients and Methods: This retrospective study included patients who underwent femtosecond laser-assisted in situ keratomileusis (LASIK) for myopia/myopic astigmatism. Two random stratified samples of patients who underwent either 1stgeneration (WaveScan, Johnson & Johnson Vision, Santa Ana, CA) or 3rd generation (iDesign 2.0, Johnson & Johnson Vision, Santa Ana, CA) treatment matched on preoperative refraction were compared (4290 eyes of 2145 patients in each group). One-month postoperative visual, refractive, and patient-reported outcomes were analyzed. Refractive and monocular visual acuity analyses were performed using one random eye of each patient. Results: The percentage of eyes achieving 20/20 or better uncorrected vision was 91.3% (1958/2145) in the 1st generation group and 95.9% (2056/2145) in the 3rd generation group (p<0.01). Binocularly, the percentage of patients with 20/20 or better UDVA was 97.0% (2080/2145) and 99.2% (2127/2145) in the 1st and 3rd generation groups, respectively (p<0.01). The mean postoperative MSE was -0.01 ± 0.33 D in the 1st generation group and +0.19 ± 0.33 D in the 3rd generation group (p<0.01). Postoperative refractive astigmatism had a mean value of -0.20 ± 0.26 D and -0.18 ± 0.24 D in the 1st and 3rd generation groups, respectively (p<0.01). The mean correction index of refractive astigmatism was 1.09 ± 0.53 in the 1st generation group and 1.02 ± 0.38 in the 3rd generation group, p<0.01. The overall percentage of patients satisfied with vision was 92.8% (1991/2145 patients) in the 1st generation group and 97.3% (2087/2145 patients) in the 3rd generation group (p<0.01). Conclusion: For the majority of postoperative variables, there were significant differences between 1st and 3rd generation treatments. The 3rd generation treatments had better visual acuity outcomes and higher patient satisfaction.

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.

Comparison of an open view autorefractor with an open view aberrometer in determining peripheral refraction in children

Purpose: The aim of this study was to compare central and peripheral refraction using an open view Shin-Nippon NVision-K 5001 autorefractor and an open view COAS-HD VR aberrometer in young children.MethodsCycloplegic central and peripheral autorefraction was measured in the right eye of 123 children aged 8 to 16 years. Three measurements each were obtained with both Shin-Nippon NVision-K 5001 autorefractor and COAS-HD VR aberrometer along the horizontal visual field up to 30° (nasal and temporal) in 10° steps. The refraction from the autorefractor was compared with aberrometer refraction for pupil analysis diameters of 2.5-mm and 5.0-mm.ResultsThe Shin-Nippon was 0.30 D more hyperopic than COAS-HD VR at 2.5-mm pupil and 0.50 D more hyperopic than COAS-HD VR at 5-mm pupil for central refraction. For both pupil sizes, the 95% limits of agreement were approximately 0.50 D for central refraction, and limits were wider in the nasal visual field compared to the temporal visual field. The mean difference for both J0 and J45 were within 0.15 D and the 95% limits of agreement within 0.90 D across the horizontal visual field.ConclusionDefocus components were similar between the Shin-Nippon autorefractor and the COAS-HD VR aberrometer with a 2.5-mm pupil for most visual field angles. However, there was a significant difference in defocus component between the Shin-Nippon autorefractor and the COAS-HD VR aberrometer with a 5.0-mm pupil, wherein the autorefractor measured more hyperopia. The astigmatic components J0 and J45 were similar between instruments for both central and peripheral refraction. (AU)

Agreement of anterior segment measurements between LenStar LS 900 optical biometer and OPD Scan III wavefront aberrometer devices in eyes with cataract.

PURPOSE: To compare the inter-device agreement of anterior eye segment measurements between LenStar LS 900 optical biometer and OPD Scan III wavefront aberrometer. METHODS: This is a retrospective study involving 59 patients (78 eyes) with cataract. Their angle Alpha, angle Kappa, pupil size and white-to-white (WTW) distance were measured by LenStar LS 900 optical biometer and OPD Scan III wavefront aberrometer, respectively, and pairwise agreement comparisons were performed between them. RESULTS: The most agreement of various parameters was occurred, with intraclass correlation coefficient (ICC) of WTW = 0.930; angle Alpha = 0.853; angle Kappa = 0.898; and pupil size = 0,976 in bright environment. Furthermore, in dark environment, the ICC of WTW, angle Alpha, angle Kappa, and pupil size were 0.927, 0.791, 0.915, and 0.990, respectively. Bland-Altman plot showed similar excellent agreement in the outcomes of the two devices for these measurements testing. CONCLUSIONS: There was an excellent agreement between the LenStar LS 900 optical biometer and OPD Scan III wavefront aberrometer for WTW, angle Alpha, angle Kappa, and pupil size measurements. In clinical practice, these measurements obtained by LenStar LS 900 optical biometer and OPD Scan III wavefront aberrometer can be used interchangeably.

Comparison of an open view autorefractor with an open view aberrometer in determining peripheral refraction in children.

PURPOSE: The aim of this study was to compare central and peripheral refraction using an open view Shin-Nippon NVision-K 5001 autorefractor and an open view COAS-HD VR aberrometer in young children. METHODS: Cycloplegic central and peripheral autorefraction was measured in the right eye of 123 children aged 8 to 16 years. Three measurements each were obtained with both Shin-Nippon NVision-K 5001 autorefractor and COAS-HD VR aberrometer along the horizontal visual field up to 30° (nasal and temporal) in 10° steps. The refraction from the autorefractor was compared with aberrometer refraction for pupil analysis diameters of 2.5-mm and 5.0-mm. RESULTS: The Shin-Nippon was 0.30 D more hyperopic than COAS-HD VR at 2.5-mm pupil and 0.50 D more hyperopic than COAS-HD VR at 5-mm pupil for central refraction. For both pupil sizes, the 95% limits of agreement were approximately 0.50 D for central refraction, and limits were wider in the nasal visual field compared to the temporal visual field. The mean difference for both J0 and J45 were within 0.15 D and the 95% limits of agreement within 0.90 D across the horizontal visual field. CONCLUSION: Defocus components were similar between the Shin-Nippon autorefractor and the COAS-HD VR aberrometer with a 2.5-mm pupil for most visual field angles. However, there was a significant difference in defocus component between the Shin-Nippon autorefractor and the COAS-HD VR aberrometer with a 5.0-mm pupil, wherein the autorefractor measured more hyperopia. The astigmatic components J0 and J45 were similar between instruments for both central and peripheral refraction.

Comparative Analysis of the Visual, Refractive and Aberrometric Outcome with the Use of 2 Intraocular Refractive Segment Multifocal Lenses.

To demonstrate the results of ray tracing higher- and lower-order aberrations in pseudophakic eyes with rotationally asymmetrical segment multifocal lenses, total high- and low-order aberrations, measured by root mean square value (RMS), refraction, uncorrected distance and uncorrected near visual acuity (UCDVA and UCNVA), and tear break-up time, were measured at scotopic size in 42 eyes of patients implanted with bifocal refractive Mplus15/Mplus30 IOL with +1.5 dpt near addition (42 eyes of patients implanted with Mplus15)/+3.0 dpt near addition (91 eyes of patients implanted with Mplus30), and 107 eyes of control group. No significant differences were noticed between the examined groups concerning UCDVA, UCNVA, and tear break-up time (p < 0.001). Coma and total high-order aberrations were significantly higher for the Mplus30 lens in comparison to the Mplus15 lens and the control group (Coma, Trefoil p < 0.001, Secondary Astigmatism p = 0.002). The spherical aberrations were significantly higher in the lower-addition lens (p = 0.016) in comparison to the control group and to the higher-addition lens group (p < 0.001). Both intraocular lens models were successful at reaching refractive aim, good distance, and near function with the lower higher-order aberrations for the low-addition lens.

Serially Checked Spherical Aberration Can Evaluate the Anti-Myopia Effect of Orthokeratology Lens in Children.

We aimed to investigate the changes in higher-order aberrations (HOAs) after wearing orthokeratology (OK) lenses in myopic patients. The study included 15 eyes from ten myopic patients, whose refractive error was myopia less than -4.5 diopters (D) and astigmatism less than 1.5 D. Uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA) were measured, and Zywave® aberrometry was performed at baseline and 1, 3, and 6 months following OK lens wear. The mean age was 11.5 years (range: 9-15 years). There was a significant improvement in UCVA (p ≤ 0.001) and a decrease in the spherical equivalent measured with auto-refraction at 6 months (p ≤ 0.001). Total HOAs significantly increased after OK lens wear (p ≤ 0.001), with spherical aberration increasing approximately 3.9-fold (p = 0.05). Spherical aberration demonstrated statistically significant positive correlations with the change in spherical equivalent at 3 and 6 months (p = 0.007 and 0.003, respectively). After wearing properly prescribed OK lens, all subjects had significantly improved UCVA and decreased myopic spherical equivalent, with increased total HOAs and positive spherical aberration at 1 month, and the changes were maintained at 6 months. Serially checked spherical aberration could evaluate the anti-myopia effect of the orthokeratology lens in children.

Accommodation lags are higher in myopia than in emmetropia: Measurement methods and metrics matter.

PURPOSE: To determine whether accommodative errors in emmetropes and myopes are systematically different, and the effect of using different instruments and metrics. METHODS: Seventy-six adults aged 18-27 years comprising 24 emmetropes (spherical equivalent refraction of the dominant eye +0.04 ± 0.03 D) and 52 myopes (-2.73 ± 0.22 D) were included. Accommodation responses were measured with a Grand Seiko WAM-5500 and a Hartmann-Shack Complete Ophthalmic Analysis System aberrometer, using pupil plane (Zernike and Seidel refraction) and retinal image plane (neural sharpness-NS; and visual Strehl ratio for modulation transfer function-VSMTF) metrics at 40, 33 and 25 cm. Accommodation stimuli were presented to the corrected dominant eye, and responses, referenced to the corneal plane, were determined in the fellow eye. Linear mixed-effects models were used to determine influence of the refractive group, the measurement method, accommodation stimulus, age, race, parental myopia, gender and binocular measures of heterophoria, accommodative convergence/accommodation and convergence accommodation/convergence ratios. RESULTS: Lags of accommodation were affected significantly by the measurement method (p < 0.001), the refractive group (p = 0.003), near heterophoria (p = 0.002) and accommodative stimulus (p < 0.05), with significant interactions between some of these variables. Overall, emmetropes had smaller lags of accommodation than myopes with respective means ± standard errors of 0.31 ± 0.08 D and 0.61 ± 0.06 D (p = 0.003). Lags were largest for the Grand Seiko and Zernike defocus, intermediate for NS and VSMTF, and least for Seidel defocus. CONCLUSIONS: The mean lag of accommodation in emmetropes is approximately equal to the previously reported depth of focus. Myopes had larger (double) lags than emmetropes. Differences between methods and instruments could be as great as 0.50 D, and this must be considered when comparing studies and outcomes. Accommodative lag increased with the accommodation stimulus, but only for methods using a fixed small pupil diameter.

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.

Accuracy evaluation of objective refraction using the wavefront aberrometer in pseudophakic eyes.

PURPOSE: To evaluate the accuracy of wavefront-derived objective refraction in pseudophakic eyes. METHODS: Retrospective case series. A total of 356 eyes (356 patients) that underwent phacoemulsification and posterior chamber intraocular lens implantation were included. Noncycloplegic subjective manifest refraction (MR) and objective refraction results from the wavefront aberrometer were obtained and compared. Subgroup analysis of objective refraction at 2.6-mm zone was performed based on axial length (AL) and average keratometry. RESULTS: The biases (at the 2.6-mm, 3-mm, and 4-mm zones) were - 0.29 ± 0.37 D, - 0.53 ± 0.41 D, and - 0.51 ± 0.60 D for sphere; - 0.27 ± 0.36 D, - 0.52 ± 0.38 D, and - 0.53 ± 0.51 D for spherical equivalent (SE); 0.03 ± 0.20 D, 0.03 ± 0.22 D, and 0.04 ± 0.27 D for J0; and 0.01 ± 0.16 D, 0.03 ± 0.22 D, and 0.01 ± 0.22 D for J45, respectively. Objective refraction for sphere, SE, and J0 (at 2.6 mm, 3 mm, and 4 mm) was significantly different from MR (P < 0.05), while J45 values were equal. The objective refraction at 2.6 mm was the most accurate in short eyes (≤ 22.5 mm) with a minimum bias for SE (- 0.15 ± 0.28 D) and highest percentage of SE within ± 0.25 to ± 0.75 D of MR. However, there was no difference between the keratometry subgroups. CONCLUSIONS: The wavefront aberrometer achieved the best accuracy at 2.6 mm in pseudophakic eyes with short AL. It still needs modification to be used as a substitute for MR in such patients.

Clinical evaluation of the repeatability of ocular aberrometry obtained with a new pyramid wavefront sensor.

PURPOSE: To evaluate the intrasubject repeatability of the ocular aberrometry obtained with a new ocular pyramidal aberrometer technology in a sample of normal eyes. METHODS: A total of 53 healthy eyes of 53 subjects with ages ranging from 18 to 45 years were included in this study. In all cases, three consecutive acquisitions were obtained. Intrasubject repeatability of the measurements with a pyramidal aberrometer was calculated. Intrasubject repeatability for 4.0- and 6.0-mm pupils was evaluated within the subject standard deviation (Sw) and intraclass correlation coefficient. RESULTS: Low values of the Sw and intraclass correlation coefficient outcomes close to 1 were observed for the sphere and cylinder at 3.0-mm pupil size. Most low Sw and intraclass correlation coefficient values close to 1 were observed for total, low-order aberrations and higher-order aberrations root mean square and for each Zernike coefficient analysis (intraclass correlation coefficient ⩾0.798) at 4.0-mm pupil size, with more limited outcomes for the aberrometric coefficient of Z(4, 4) with an intraclass correlation coefficient of 0.683. For a 6.0 mm pupil diameter, low Sw and intraclass correlation coefficient values close to 1 were observed for all aberrometric parameters or Zernike coefficients analyzed (intraclass correlation coefficient ⩾0.850). CONCLUSION: The new pyramidal aberrometer Osiris provides repeatable and consistent measurements of ocular aberrometry measurements in normal eyes.

In-Vivo Evaluation of Peripheral Refraction Changes with Single Vision and Multifocal Soft Contact Lenses.

This study investigated in-vivo changes of peripheral refraction with commercially available single vision and multifocal soft contact lenses, utilizing different designs and various corrective power values. Starting at the fovea, wave-front aberrations were measured up to 30o nasal retinal eccentricity, in 10o increments, using a commercially available Shack-Hartmann aberrometer. Three different types of contact lenses were fitted in an adult subject's right eye: Acuvue Oasys Single Vision (ASV), Proclear Multifocal D with 2.50 diopters (D) add power (PMD), and ArtMost SoftOK (SOK). Each lens type was fitted in corrective power values of -2.00 D, -4.00 D, and -6.00 D. Refractive errors were computed in power vector notation: The spherical equivalent (M), the Cartesian Jackson-Cross-Cylinder (J0), and the oblique Jackson Cross Cylinder (J45) from measured second order Zernike terms. Acuvue Oasys Single Vision lenses produced a slight myopic shift at 30o retinal periphery (-0.32 D ± 0.05) without significant differences between the various lens power values. Proclear Multifocal D lenses did not create clinically significant myopic shifts of at least -0.25 D. All SOK lenses produced clinically significant relative myopic shifts at both 20o (-0.61 D ± 0.08) and 30o (-1.42 D ± 0.15) without significant differences between the various lens power values. For all lens types and power values, off-axis astigmatism J0 was increased peripherally and reached clinical significance beyond 20o retinal eccentricity. The increased amount of off-axis astigmatism J0 did not show a significant difference for the same type of lenses with different dioptric power. However, at 30o retinal eccentricity, SOK lenses produced significantly higher amounts of off-axis astigmatism J0, compared with ASV and PMD lenses (SOK versus ASV versus PMD: -1.67 D ± 0.09, -0.81 D ± 0.07, and -0.72 D ± 0.15). Both ASV and SOK lenses showed no clinically significant differences in the amount of introduced astigmatic retinal image blur, with various lens power values. Proclear Multifocal D lenses showed a systematic increase of astigmatic retinal image blur with an increase of add power. At 30o retinal eccentricity, -6.00 D SOK lenses introduced 0.73 D astigmatic retinal image blur, while PMD and ASV lenses introduced 0.54 D and 0.37 D, respectively. In conclusion, relative peripheral refractions, measured in-vivo, were independent of the contact lenses central corrective power. The SOK contact lenses demonstrated a stronger capability in rendering relative peripheral myopic defocus into far periphery, compared to the other lens designs used in this study. This was accompanied by higher amounts of introduced astigmatic retinal image blur.

Profile of off-axis higher order aberrations and its variation with time among various refractive error groups.

Peripheral higher order aberrations (HOA) of 646 children at 30° temporal, nasal and inferior visual field were measured under cycloplegia (5 mm pupil diameter) using a commercially available Shack-Hartmann aberrometer in the Sydney Myopia Study [age, 12.7 ±â€¯0.4 years (mean ±â€¯standard deviation)] and five years later in the Sydney Adolescent Vascular and Eye Study. At baseline, 176 eyes were emmetropic, 95 were myopic and 375 were hyperopic. Coma, 3rd order and RMS of coma increased with eccentricity for all eyes and no difference was observed for 4th order and RMS of C(4,0) among refractive error groups. More positive C(4,0) was observed for hyperopic eyes at periphery. At follow up, 26% had 'myopic change' and 70% had 'no change' in refractive error. At follow-up, horizontal coma became more negative at nasal field and more positive at temporal field for all eyes. More positive C(4,0) for hyperopic eyes at baseline may indicate variation in optical characteristics of peripheral cornea and crystalline lens. An increase in horizontal coma with time, irrespective of refractive error change, may be attributed to variation in the shape factor of peripheral cornea and crystalline lens and/or misalignment of optical surfaces/components relative to the visual axis (angle kappa) as the eye grows in axial length.

Visual, aberrometric, photic phenomena, and patient satisfaction after myopic wavefront-guided LASIK using a high-resolution aberrometer.

PURPOSE: The purpose of this study was to evaluate the visual, refractive, and aberrometric outcomes as well as the level of patient satisfaction and photic phenomena after myopic laser in situ keratomileusis (LASIK) surgery using wavefront-guided (WFG) ablations based on measurements obtained with a high-resolution aberrometer. PATIENTS AND METHODS: This study was a prospective analysis including 253 eyes of 127 patients (aged between 19 years and 54 years) undergoing WFG LASIK using the STAR S4 IR Excimer Laser System combined with the iDesign System and iFS Femtosecond Laser. Visual, refractive, and aberrometric outcomes during a 2-month follow-up as well as patient satisfaction and photic phenomena were evaluated by means of a questionnaire. RESULTS: A total of 85% (215/253) and 99% (251/253) of eyes achieved a postoperative (Postop) uncorrected distance visual acuity of 20/16 and 20/20, respectively, and all eyes achieved an uncorrected distance visual acuity of 20/25. Postop spherical equivalent values were within ±0.25 D and ±0.50 D in 97% and 100% of eyes, respectively. Likewise, manifest cylinder was <0.25 D in 97% (245/253) of eyes. A statistically significant reduction was found in the total root mean square (P<0.001) and in the level of primary spherical aberration (P=0.001). Postop difficulties related to vision were graded as minimal, with low levels of photic phenomena and high levels of patient satisfaction. The level of difficulty to perform daily activities and the level of glare perceived by patients while driving car were significantly decreased (P<0.001). CONCLUSION: WFG LASIK surgery using the technology evaluated is predictable and effective for the correction of myopia and leads to high levels of patient satisfaction.

Evaluation of patient visual comfort and repeatability of refractive values in non-presbyopic healthy eyes.

AIM: To evaluate the intra-operator repeatability in healthy subjects using the WAM-5500 auto-kerato/refractometer and the iTrace aberrometer, to compare the refractive values and the subjective refraction obtained with both devices and to determine which of these three spherocylindrical corrections allows the subject to achieve the best visual comfort. METHODS: Forty-two non-presbyopic healthy eyes of 42 subjects were enrolled in this prospective study. Refractive values were compared, evaluating the repeatability, the relationship between the methods and the best visual comfort obtained. RESULTS: Sphere, cylinder and axis results showed good intraclass correlation coefficients (ICC); the highest ICC was obtained using the spherical refraction with the autorefractometer and the aberrometer, achieving levels of 0.999 and 0.998, respectively. The power vector (PV) was calculated for each refraction method, and the results indicated that there were no statistically significant differences between them (P>0.05). Direct comparison of PV measurements using the three methods showed that aberrometer refraction gave the highest values, followed by the subjective values; the autorefractometer gave the lowest values. The subjective method correction was most frequently chosen as the first selection. Equal values were found for the autorefractometer and the aberrometer as the second selection. CONCLUSION: The iTrace aberrometer and the WAM-5500 auto-kerato/refractometer showed high levels of repeatability in healthy eyes. Refractive corrections with the aberrometer, the autorefractometer and subjective methods presented similar results, but spherocylindrical subjective correction was the most frequently selected option. These technologies can be used as complements in refractive evaluation, but they should not replace subjective refraction.

Clinical outcomes of wavefront-guided laser in situ keratomileusis to treat moderate-to-high astigmatism.

PURPOSE: The purpose of this study was to evaluate the refractive and visual outcomes of wavefront-guided laser in situ keratomileusis (LASIK) in eyes with myopic astigmatism and cylindrical component ≥2.0 diopter (D). METHODS: In this retrospective study, 611 eyes that underwent LASIK for simple or compound myopic astigmatism were analyzed. Preoperative refractive cylinder ranged from -2.00 D to -6.00 D (mean -2.76±0.81 D), and the sphere was between 0.00 D and -9.75 D (mean -2.79±2.32 D). Predictability, visual outcomes, and vector analysis of changes in refractive astigmatism were evaluated. RESULTS: At 3 months after LASIK, 83.8% of eyes had uncorrected distance visual acuity of 20/20 or better, 90.3% had manifest spherical equivalent within ±0.50 D, and 79.1% had residual refractive cylinder within ±0.50 D of intended correction. The mean correction ratio for refractive cylinder was 0.92±0.14, the mean error of angle was -0.45°±2.99°, and the mean error vector was 0.37±0.38 D. A statistically significant correlation was found between the error of magnitude (arithmetic difference in the magnitudes between surgically induced refractive correction and intended refractive correction) and the intended refractive correction (r=0.26, P<0.01). CONCLUSION: Wavefront-guided LASIK for the correction of myopic astigmatism is safe, effective, and predictable.

Comparing the relative peripheral refraction effect of single vision and multifocal contact lenses measured using an autorefractor and an aberrometer: A pilot study.

PURPOSE: To compare the contributions of single vision (SVCL) and multifocal contact lenses (MFCL) to the relative peripheral refraction (RPR) profiles obtained via an autorefractor and an aberrometer in a pilot study. METHODS: Two instruments, Shin-Nippon NVision K5001 (SN) and COAS-HD, were modified to permit open field PR measurements. Two myopic adults (CF, RB) were refracted (cycloplegia) under eight conditions: baseline (no CL); three SVCLs: Focus Dailies(®) (Alcon, USA), PureVision(®) (Bausch & Lomb, USA) and AirOptix(®) (Alcon, USA); and four MFCLs: AirOptix(®) (Alcon, USA), Proclear(®) Distant and Near (Cooper Vision, USA), and PureVision(®) (Bausch & Lomb, USA). CLs had a distance prescription of -2.00D and for MFCLs, a +2.50D Add was selected. Five independent measurements were performed at field angles from -40° to +40° in 10° increments with both instruments. The COAS-HD measures were analyzed at 3mm pupil diameter. Results are reported as a change in the relative PR profile, as refractive power vector components: M, J180, and J45. RESULTS: Overall, at baseline, M, J180 and J45 measures obtained with SN and COAS-HD were considerably different only for field angles ≥±30°, which agreed well with previous studies. With respect to M, this observation held true for most SVCLs with a few exceptions. The J180 measures obtained with COAS-HD were considerably greater in magnitude than those acquired with SN. For SVCLs, the greatest difference was found at -40° for AirOptix SV (ΔCF=3.20D, ΔRB=1.56D) and for MFCLs it was for Proclear Distance at -40° (ΔCF=2.58D, ΔRB=1.39D). The J45 measures obtained with SN were noticeably different to the respective measures with COAS-HD, both in magnitude and sign. The greatest difference was found with AirOptix Multifocal in subject RB at -40°, where the COAS-HD measurement was 1.50D more positive. In some cases, the difference in the RPR profiles observed between subjects appeared to be associated with CL decentration. CONCLUSION: For most test conditions, distinct differences were observed between the RPR measures obtained with the two modified instruments. The differences varied with CL design and centration. Although the pilot study supports the interchangeable use of the two instruments for on- and off-axis refraction in unaided eyes or eyes corrected with low/no spherical aberration; we advocate the use of the COAS-HD over the SN for special purposes like refracting through multifocal CLs.

Comparison of wavefront aberrations in rabbit and human eyes.

BACKGROUND: The rabbit is one of the most common animal models used for preclinical safety evaluation of new cataract surgery and laser vision-correction technologies in ophthalmic research; however, the distributions of wavefront aberrations in rabbit eyes are unknown. The purpose of this study was to investigate the similarities and differences of wavefront aberrations between rabbit and human eyes. METHODS: Monochromatic wavefront aberrations of left and right eyes of 12 rabbits and 12 human subjects with normal vision were measured by a commercial aberrometer (WaveScan Wavefront System, Abbott Medical Optics Inc, California, USA). Comparison of wavefront aberrations in rabbit and human eyes is based on a 6.0 mm pupil. RESULTS: The rabbit eyes have an average spherical refraction of 1.51 ± 0.83 D and a cylindrical refraction of -1.03 ± 0.63 D. The average spherical refractive error of the human eyes used in this study was -2.03 ± 2.59 D with a cylindrical refraction of -1.27 ± 1.01 D. The average wavefront error root-mean-square (RMS) from higher-order aberrations is 0.34 µm in rabbits (6.0 mm pupil), which is higher compared to the wavefront error RMS value of human eyes (0.26 µm). The largest higher-order aberration in rabbit eyes is vertical coma (Z7, 0.19 ± 0.16 µm), whereas the largest higher-order aberration in human eyes is spherical aberration (Z12, 0.07 ± 0.13 µm). Wavefront error RMS, vertical coma and some higher-order aberrations are significantly correlated between the right and left rabbit eye. CONCLUSION: Compared to wavefront aberrations in the human eye measured in this study, the rabbit eye has less refractive error but larger higher-order aberrations both in wavefront error RMS and some higher-order aberration terms. Similar to human eyes, wavefront error and some higher-order aberrations are significantly correlated between the right and left rabbit eye.

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.

Evaluation of the auto-refraction function of the Nidek OPD-Scan III.

BACKGROUND: The aim was to evaluate the validity and repeatability of the auto-refraction function of the Nidek OPD-Scan III (Nidek Technologies, Gamagori, Japan) compared with non-cycloplegic subjective refraction. The Nidek OPD-Scan III is a new aberrometer/corneal topographer workstation based on the skiascopy principle. It combines a wavefront aberrometer, topographer, autorefractor, auto keratometer and pupillometer/pupillographer. METHODS: Objective refraction results obtained using the Nidek OPD-Scan III were compared with non-cycloplegic subjective refraction for 108 eyes of 54 participants (29 female) with a mean age of 23.7 ± 9.5 years. Intra-session and inter-session variability were assessed on 14 subjects (28 eyes). RESULTS: The Nidek OPD-Scan III gave slightly more negative readings than results obtained by subjective refraction (Nidek mean difference -0.19 ± 0.36 DS, p < 0.01 for sphere; -0.19 ± 0.35 DS, p < 0.01 for mean spherical equivalent; -0.002 ± 0.23 DC, p = 0.91 for cylinder; -0.06 ± 0.38 DC, p = 0.30 for J0 and -0.36 ± 0.31 DC for J45, p = 0.29). Auto-refractor results for 74 per cent of spherical readings and 60 per cent of cylindrical powers were within ± 0.25 of subjective refraction. There was high intra-session and inter-session repeatability for all parameters; 90 per cent of inter-session repeatability results were within 0.25 D. CONCLUSION: The Nidek OPD-Scan III gives valid and repeatable measures of objective refraction when compared with non-cycloplegic subjective refraction.