Precision of a commercial hartmann-shack aberrometer: limits of total wavefront laser vision correction

Repeatability of pyramidal aberrometer measurements in keratoconus and normal eyes

PURPOSE

To evaluate the intrasubject repeatability of pyramidal aberrometer measurements in a sample of keratoconus and normal eyes.

SETTING

American University of Beirut Medical Center, Beirut, Lebanon.

DESIGN

Prospective comparative repeatability analysis.

METHODS

Study population: Keratoconus and normal eyes from adult patients. Observation procedures: Each eye was evaluated with 3 consecutive acquisitions using a pyramidal aberrometer. Main outcome measures: The repeatability of different ocular higher-order aberrations and lower-order aberrations (HOAs and LOAs, respectively), and Zernike coefficients down to the fifth order, was evaluated. Repeatability was assessed by within-subject SDs (Sw), repeatability limits ( r ), and intraclass correlation coefficients (ICCs), among other parameters.

RESULTS

72 keratoconus patients (72 eyes) and 76 normal patients (76 eyes) were included. In normal and keratoconus eyes, the ICC of total LOAs and HOAs, as well as each of the Zernike coefficients, was >0.9. The Sw for keratoconus eyes with mean maximal keratometry (Kmax) <50 diopters (D) was 0.1345 for total LOAs, 0.0619 for total HOAs, 0.0292 for horizontal coma, 0.0561 for vertical coma, and 0.0221 for spherical aberration as compared with 0.2696, 0.1486, 0.0972, 0.1497, and 0.0757 for keratoconus eyes with Kmax ≥50 D. Similar trend of better repeatability for grade 1 keratoconus and HOAs <2 D as compared with grades 2 and 3 keratoconus and eyes with HOAs >2 D were also noted.

CONCLUSIONS

Ocular aberrometer measurements generated by high definition pyramidal aberrometers have high repeatability in both normal and mild keratoconus eyes and moderate repeatability, yet still clinically acceptable, in advanced keratoconus. This is of particular importance in ocular wavefront-guided treatments.

Comparing the clinical applicability of wavefront phase imaging in keratoconus versus normal eyes

The aim of this work is to quantitatively assess the wavefront phase of keratoconic eyes measured by the ocular aberrometer t·eyede (based on WaveFront Phase Imaging Sensor), characterized by a lateral resolution of 8.6 µm without requiring any optical element to sample the wavefront information. We evaluated the parameters: root mean square error, Peak-to-Valley, and amplitude of the predominant frequency (Fourier Transform analysis) of a section of the High-Pass filter map in keratoconic and healthy cohorts. Furthermore, we have analyzed keratoconic eyes that presented dark-light bands in this map to assess their period and orientation with the Fourier Transform. There are significant statistical differences (p value < 0.001) between healthy and keratoconic eyes in the three parameters, demonstrating a tendency to increase with the severity of the disease. Otherwise, the quantification of the bands reveals that the width is independent of eye laterality and keratoconic stage as orientation, which tends to be oblique. In conclusion, the quantitative results obtained with t·eyede could help to diagnose and monitor the progression of keratoconus.

Ultra-High Resolution Optical Aberrometry in Patients with Keratoconus: A Cross-Sectional Study

INTRODUCTION

This study performs optical aberration assessment in patients using a novel ultra-high-resolution device. The objective of this study is to analyze optical aberrations, especially the very high order wavefront (more than 10th order of Zernike coefficients), and compare between keratoconus and healthy patients.

METHODS

In this cross-sectional study, we analyzed 43 eyes from 25 healthy patients and 43 eyes from 27 patients with keratoconus using corneal tomography and a very high-resolution (8.55 µm) aberrometer prototype (T-eyede) outfitted with a sensor originally developed for use in the field of astrophysics. Corneal aberration values were assessed using an optical model built with Zemax optical software, while ocular aberrations were assessed using T-eyede. In addition, image-processing analysis was performed of the wavefront phase, creating a high-pass filter map.

RESULTS

We found lower values for ocular aberrations than corneal aberrations in both groups (p < 0.001). Specifically, we found a reduction in primary astigmatism (0.145 µm) and primary coma (0.017 µm). Also, the keratoconus group showed significantly higher wavefront aberration values compared with controls (p < 0.001). An analysis of the high-pass filter map revealed 2 contrasting results: one smooth or clear, while the other presented a banding pattern. Almost all in the control group (95%) showed the first pattern, while 77% of the keratoconus group showed a banding pattern on the filtered map (chi-squared test, p < 0.001).

CONCLUSION

This device provides reliable, precise measurements of ocular aberrations that correlate well with corneal aberrations. Furthermore, the extraordinary high-resolution measurements revealed unprecedented micro changes in the wavefront phase of patients with keratoconus that varied with disease stage. These findings could lead to new screening or follow-up methods.

Reliability and agreement of apparent chord mu measurements between static and dynamic evaluations

PURPOSE

To assess the repeatability and agreement of Cartesian coordinates and the length of apparent chord mu and pupil diameter measurements during static (Galilei G4) and dynamic (Topolyzer Vario) evaluations.

SETTING

IOBA-Eye Institute, Valladolid, Spain.

DESIGN

Case series.

METHODS

3 consecutive measurements per scenario (Galilei G4 and Topolyzer Vario under low mesopic and photopic conditions) were performed by the same clinician. The intrasession repeatability was assessed using the within-subject SD (Sw), the precision, the coefficient of variation, and the intraclass correlation coefficient (ICC). The agreement was analyzed using repeated-measures analysis of variance and the Bland-Altman method.

RESULTS

Thirty-seven healthy participants were recruited. The Sw values for chord mu parameters and pupil diameter ranged from 0.01 to 0.03 and 0.08 to 0.21, respectively. The ICC was ≥0.89 for all parameters. Galilei G4 and Topolyzer Vario under low mesopic and photopic conditions provided significantly different measures of apparent chord mu length (0.23 ± 0.11 mm, 0.30 ± 0.10 mm, and 0.25 ± 0.11 mm, respectively, P ≤ .02), X-coordinate (-0.18 ± 0.12 mm, -0.27 ± 0.11 mm, and -0.21 ± 0.12 mm, respectively, P < .001), and pupil diameter (3.38 ± 0.50 mm, 6.29 ± 0.60 mm, and 3.04 ± 0.41 mm, respectively, P < .001). Y-coordinate values obtained by Galilei G4 and Topolyzer Vario under low mesopic conditions were significantly different (0.06 ± 0.13 mm vs 0.03 ± 0.11 mm, respectively, P = .02), in contrast to Galilei G4 and Topolyzer Vario under photopic conditions (0.05 ± 0.13 mm, P = .82) and both illumination conditions of Topolyzer Vario (P ≥ .23).

CONCLUSIONS

Galilei G4 and Topolyzer Vario provide consistent measurements of apparent chord mu Cartesian coordinates and length, as well as pupil diameter; however, the measurements are not interchangeable. Ophthalmic surgeons should consider these findings when planning customized intraocular lens implantation and refractive surgery procedures.

Repeatability and Agreement of a New Scheimpflug Device and a Hartmann-Shack Aberrometer With a Ray-Tracing Aberrometer in Normal, Keratoconus, and CXL Groups

PURPOSE

To assess repeatability and agreement of a Scheimpflug topographer and a Hartmann-Shack aberrometer with a ray-tracing aberrometer in normal, keratoconus, and corneal cross-linking (CXL) groups.

METHODS

In this cross-sectional, observational study, normal, keratoconus, and CXL groups with 125 eyes in each of the three groups were included. All eyes underwent three sets of measurements, at a single visit, using the Pentacam AXL Wave (Oculus Optikgeräte GmbH) and iTrace (Tracey Technologies). Keratometry, pachymetry, objective refraction, and total ocular aberrations including root mean square (RMS) lower order aberrations (LOAs), RMS higher order aberrations (HOAs), RMS coma, and spherical aberrations (SA) were analyzed. Objective assessment of haze after CXL was done using the Pentacam AXL Wave. Repeatability was assessed using within-subject standard deviation (Sw), test-retest variability, within-subject coefficient of variation (COV), and intraclass correlation coefficient (ICC). Bland-Altman analysis assessed 95% limits of agreement and correlation coefficient (r) determined the strength of the relationship between measurements.

RESULTS

The Pentacam AXL Wave had Sw for keratometry of 0.12 in the normal group and 0.15 in the keratoconus group and lower (poorer) Sw of 0.17 in the CXL group. For pachymetry, Sw was 9.18, 9.53, and 10.11 in the normal, keratoconus, and CXL groups, respectively. Total aberrations had ICCs ranging from 0.88 for RMS HOAs to 0.95 for SA in the normal group, 0.86 for RMS HOAs to 0.92 for SA in the keratoconus group, and 0.72 for RMS HOAs to 0.82 for SA (poorer) in the CXL group. In the normal group, mean differences between the two devices were nonsignificant for all parameters except SA (0.011 ± 0.038 μm, P < .01; limits of agreement = -0.09 to 0.07; r = 0.87). In the keratoconus group, mean differences were significant in all aberrations except RMS LOAs (-0.27 ± 0.85 μm, P = .10; limits of agreement = -3.3 to 3.8; r = 0.92). In the CXL group, all parameters varied significantly (P < .006).

CONCLUSIONS

The Pentacam AXL Wave showed comparable repeatability in the normal and keratoconus groups, but was poorer in the CXL group, more so with increasing corneal haze. Both devices can be used interchangeably in normal eyes, except for SA, but not in eyes with keratoconus or CXL for aberration measurements. [J Refract Surg. 2022;38(3):201-208.].

The optics of the human eye at 8.6 µm resolution

Ocular optics is normally estimated based on up to 2,600 measurement points within the pupil of the eye, which implies a lateral resolution of approximately 175 µm for a 9 mm pupil diameter. This is because information below this resolution is not thought to be relevant or even possible to obtain with current measurement systems. In this work, we characterize the in vivo ocular optics of the human eye with a lateral resolution of 8.6 µm, which implies roughly 1 million measurement points for a pupil diameter of 9 mm. The results suggest that the normal human eye presents a series of hitherto unknown optical patterns with amplitudes between 200 and 300 nm and is made up of a series of in-phase peaks and valleys. If the results are analysed at only high lateral frequencies, the human eye is also found to contain a whole range of new information. This discovery could have a great impact on the way we understand some fundamental mechanisms of human vision and could be of outstanding utility in certain fields of ophthalmology.

Repeatability and Agreement of Wavefront aberrations of Pentacam AXL Wave- a new hybrid topographer and aberrometer with ITrace in healthy eyes

PURPOSE

To assess repeatability and agreement of Pentacam AXL Wave, with iTrace aberrometer.

SETTING

Narayana Nethralaya, Bangalore, India.

DESIGN

Prospective ,cross-sectional study.

METHODS

One hundred eyes of 100 patients underwent three sets of measurements, at a single visit, using Pentacam AXL Wave (Oculus, Germany) and iTrace (Tracey Technologies, USA).Lower-order aberration (LOA), higher-order aberration (HOA), Coma and Spherical Aberrations (SA) were analyzed. Repeatability was assessed using within-subject standard deviation (Sw), test-retest variability (TRT), within-subject coefficient of variation (COV) and Intraclass Correlation Coefficient (ICC). The Bland-Altman analysis was used to assess 95% limits of agreement (LoA) and the correlation coefficient (r) to determine strength of relationship between measurements.

RESULTS

All measurements with Pentacam AXL Wave had repeatability with an ICC for total ocular aberrations ranging from 0.84 for HOAto 0.92 for LOA and corneal from 0.76 for HOA to 0.86 for LOA The Sw, TRT, COV of all aberrations were significantly lower (better) than those of iTrace (p < 0.001). The mean differences between 2 devices were insignificant for the comparison of all parameters, except for spherical aberration (0.011(0.002571 to 0.02008; P= 0.01). Both devices showed excellent corelations for ocular aberrations (tHOA (P=0.12,LoA= -0.52 to 0.025; r= 0.89); LOA (P=0.14, LoA = -2.71 to 2.61  ; r= 0.96) coma (P=0.27, LoA = -0.11 to 0.12; r= 0.89) and in SA (P=0.01,  LoA = -0.09 to 0.07;r=0.97)).

CONCLUSIONS

The repeatability estimates for wavefront aberrations using Pentacam AXL Wave were significantly better than that using iTrace. Both devices showed excellent corelations for total ocular aberrations.

Monochromatic higher order aberrations in highly myopic eyes with Staphyloma

BACKGROUND

Prevalence of high myopia is continuously increasing, thus, patients affected with staphyloma are abundant worldwide. Assessment of the quality of vision in these patients is mandatory for a proper clinical counselling, specially when undergoing surgical procedures that require intraocular lenses implantation. Thus, the purpose of the study was to assess monochromatic higher order aberrations (HOAs) in highly myopic eyes with staphyloma with or without a dome-shaped macula.

METHODS

Participants underwent spectral-domain optical coherence tomography, ocular axial biometry, dual Scheimpflug photography and integrated Placido disk topography, and Hartmann-Shack wavefront analysis. Five groups were evaluated: a low-moderate myopia control group (< 6.00 diopters, n = 31) and four high myopia (≥6.00 diopters) groups: eyes without staphyloma (n = 18), eyes with inferior staphyloma (n = 14), eyes with posterior staphyloma without dome-shaped macula (n = 15) and eyes with posterior staphyloma with dome-shaped macula (n = 17). Subsequently, two new groups (including all participants) were created to assess differences between myopia with and without staphyloma. One-way analysis of covariance was performed using age and lens densitometry as covariates.

RESULTS

Statistically significant (p ≤ 0.05) differences in anterior corneal fourth-order HOAs were observed between the low-moderate myopia and no-dome-shaped macula (Mean: 0.16 μm) and dome-shaped macula posterior staphyloma groups (Mean: 0.12 μm) in younger patients (≤45 years old). The same groups also showed (p ≤ 0.05) significant differences for anterior corneal primary spherical aberration (Mean: 0.19 and 0.13 μm, respectively). In addition, anterior corneal tetrafoil was significantly higher (p = 0.04) in dome-shaped macula compared to no-dome-shaped macula (Mean: 0.18 vs 0.06 μm, respectively). When all participants were grouped together, significantly lower mean anterior corneal primary spherical aberration (0.15 μm vs. 0.27 μm, p = 0.004) and higher internal primary spherical aberration (0.04 μm vs. -0.06 μm, p = 0.04) was observed in staphyloma compared to no-staphyloma myopic patients.

CONCLUSIONS

Eyes with high myopia and staphyloma have less positive anterior corneal primary spherical aberration and less negative internal primary spherical aberration, suggesting that the anterior corneal surface tends to mimic in a specular fashion the posterior pole profile. This corneal behaviour appears to change in patients older than 45 years.

Pyramidal Aberrometry in Wavefront-Guided Myopic LASIK

PURPOSE

To evaluate measurement repeatability and clinical results for pyramidal aberrometry in routine myopic wavefront-guided laser in situ keratomileusis (LASIK).

METHODS

Results from 265 consecutive eyes treated with myopic wavefront-guided LASIK using the Amaris 1050RS Excimer Laser and Peramis pyramidal aberrometer (SCHWIND eye-tech-solutions GmbH) were reviewed. Limits of repeatability were calculated for the aberrometric refraction spherical equivalent and higher order aberrations for the Peramis aberrometer using results from three consecutive scans acquired preoperatively and postoperatively for the first 100 eyes treated.

RESULTS

The 95% limits of repeatability for pyramidal aberrometric measurement were: 0.3 diopters (D) for sphere, 0.2 D for cylinder, and 0.1 D (dioptric equivalent) for 3rd and 4th order aberration indices. A total of 95% of eyes were within ±0.50 D of the manifest refraction spherical equivalent target postoperatively. Uncorrected distance visual acuity was 20/20 or better in 96% of 232 eyes with a plano refraction target outcome. A total of 97% of eyes had a refraction cylinder of 0.50 D or less. No eyes lost one or more line of corrected distance visual acuity.

CONCLUSIONS

These data demonstrate good measurement repeatability, safety, and efficacy for pyramidal aberrometry in routine myopic LASIK. [J Refract Surg. 2020;36(7):442-448.].

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 (S_w) and intraclass correlation coefficient.

RESULTS

Low values of the S_w and intraclass correlation coefficient outcomes close to 1 were observed for the sphere and cylinder at 3.0-mm pupil size. Most low S_w 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 S_w 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.

Comparison Between Aberrometry-Based Binocular Refraction and Subjective Refraction

Purpose

We evaluate the efficacy of a new system of binocular refraction, mainly based on ocular aberrometry (EYER) and compare it with the traditional subjective refraction as gold standard.

Methods

A prospective, double blind, and transversal study was performed on 99 subjects (35 men, 64 women; mean age 37.22 ± 18.04 years; range, 7–70 years). Refractive surgery or irregular cornea were considered exclusion criteria. Subjective refraction was performed by three different optometrists and EYER by other optometrists on three different days randomly. The binocular best corrected visual acuity (BBCVA), subjective vision evaluated with visual analogue scale (VAS), refraction spent time, and mean spherical equivalent (MSE), and vertical and oblique cylindrical components (J0 and J45) were analyzed.

Results

A positive strong correlation between EYER and subjective refraction was found for MSE (Pearson, 0.984; P < 0.001) and J0 and J45 (Pearson, 0.837; P < 0.001 and Pearson, 0.852; P < 0.001, respectively) in the total group. There were no statistically significant differences for BBCVA (P < 0.05). The VAS scores were 84.29 ± 12.29 with the EYER and 86.89 ± 12.38 with subjective refraction (P = 0.031). The spent time to perform the refraction was statistically lower (P < 0.05) with the EYER compared to conventional subjective refraction for all groups.

Conclusions

The EYER system showed similar results in terms of spherical and cylindrical components, visual acuity being the spent time in the refraction lower than conventional subjective refraction.

Translational Relevance

This new objective refraction system provides less chair spent time with similar results than subjective refraction.

Repeatability of a Commercially Available Adaptive Optics Visual Simulator and Aberrometer in Normal and Keratoconic Eyes

PURPOSE

To evaluate the repeatability of aberration measurement obtained by a Hartmann-Shack aberrometer combined with a visual adaptive optics simulator in normal and keratoconic eyes.

METHODS

One hundred fifteen normal eyes and 92 eyes with grade I and II keratoconus, as per the Amsler-Krumeich classification, were included in the study. To evaluate the repeatability, three consecutive measurements of ocular aberrations were obtained by a single operator. Zernike analyses up to the 5th order for a pupil size of 4.5 mm were performed. Statistical analyses included the intraclass correlation coefficient (ICC) and within-subject standard deviation (SD).

RESULTS

For intrasession repeatability, the ICC value for sphere and cylinder was 0.94 and 0.93 in normal eyes and 0.98 and 0.97 in keratoconic eyes, respectively. The ICC for root mean square of higher order aberrations (HOA_RMS) was 0.82 in normal and 0.98 in keratoconic eyes. For 3rd order aberrations (trefoil and coma), the ICC values were greater than 0.87 for normal eyes and greater than 0.92 for keratoconic eyes. The ICC for spherical aberration was 0.92 and 0.90 in normal and keratoconic eyes, respectively.

CONCLUSIONS

Visual adaptive optics provided repeatable aberrometry data in both normal and keratoconic eyes. For most of the parameters, the repeatability in eyes with early keratoconus was somewhat better than that for normal eyes. The repeatability of the Zernike terms was acceptable for 3rd order (trefoil and coma) and spherical aberrations. Therefore, visual adaptive optics was a suitable tool to perform repeatable aberrometric measurements. [J Refract Surg. 2017;33(11):769-772.].

Precision and agreement of higher order aberrations measured with ray tracing and Hartmann-Shack aberrometers

BACKGROUND

To assess the precision and agreement of measurements of higher order aberrations (HOAs) obtained with a ray tracing aberrometer (iTrace) and a Hartmann-Shack aberrometer (Topcon KR-1 W).

METHODS

Prospective evaluation of the diagnostic test. Data from the right eyes of 92 normal subjects obtained using the two devices were included in this study. Two observers performed 3 consecutive scans to determine the intraobserver repeatability and interobserver reproducibility. About one week later, one observer performed an additional 3 consecutive scans to obtain the intersession reproducibility. The within-subject standard deviation (Sw), test-retest repeatability (TRT) and intraclass correlation coefficient (ICC) were used to assess the precision, while Bland-Altman plots were performed to assess the agreement.

RESULTS

For intraobserver repeatability of the ocular, corneal and internal HOAs, Topcon KR-1 W showed a 2.77Sw of 0.079 μm or less and ICCs of 0.761 or more; and iTrace showed a 2.77Sw of 0.105 μm or less and ICCs of 0.805 or more. The ICCs of the internal HOAs of interobserver reproducibility were less than 0.75 except for spherical aberration (SA) (0.862), and interobserver reproducibility of the counterpart showed similar but lower results. For the ocular, corneal and internal HOA measurements, statistically significant differences existed between the Topcon KR-1 W and iTrace (all P < 0.05). No significant differences were observed in the ocular SA and internal coma.

CONCLUSIONS

The ray tracing and Hartmann-Shack method aberrometers provided excellent repeatability but less reliable reproducibility in the measurement of HOAs (except for SA). The two aberrometers should not be interchangeable in clinical application because of the significant differences in HOA measurements between them.

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.

Comparison of short-term refractive surgery outcomes after wavefront-guided versus non-wavefront-guided LASIK

PURPOSE

To evaluate and compare visual and refractive outcomes after laser-assisted in situ keratomileusis (LASIK) surgery for the correction of myopia or myopic astigmatism using 3 different treatment protocols.

METHODS

We included 736 eyes of 369 patients (age 18-62 years) divided into 3 groups: 235 eyes of 118 patients (MEL80 group) undergoing LASIK using optimized aspheric ablation profiles (MEL80 excimer laser; Carl Zeiss Meditec), 248 eyes of 124 patients (Wavescan group) undergoing wavefront-guided (WFG) LASIK (STAR S4IR excimer laser + Wavescan aberrometer; Abbott Medical Optics), and 253 eyes of 127 patients (iDesign group) undergoing WFG LASIK (STAR S4IR excimer laser + iDesign system; Abbott Medical Optics). Visual and refractive outcomes were evaluated 2 months after surgery.

RESULTS

A total of 91% (215/235), 95% (237/248), and 99% (251/253) of eyes achieved a postoperative uncorrected distance visual acuity of 0.0 logMAR (≈20/20) in the MEL80, Wavescan, and iDesign groups, respectively. Postoperative spherical equivalent (SE) was within ±0.5 D in 95% (223/235), 98% (242/248), and 100% (253/253) of eyes in these same 3 groups, respectively. Likewise, manifest cylinder was below 0.50 D in 95% (223/235), 97% (241/248), and 100% (253/253) of eyes. Significant differences in postoperative SE and cylinder were found between the MEL80 and iDesign groups (p&lt;0.05).

CONCLUSIONS

All evaluated LASIK treatment protocols are predictable and effective for the correction of myopia. The treatment planned with a high resolution aberrometer obtained the best postoperative refractive outcomes.

Objective and subjective visual quality after implantation of all optic zone diffractive multifocal intraocular lenses: a prospective, case-control observational study

BACKGROUND AND AIMS

To evaluate the objective and subjective optical quality of all optic zone diffractive multifocal intraocular lens (IOL).

METHODS

Fifty patients (50 eyes) having phacoemulsification and IOL implantation surgery were enrolled. 25 patients were implanted with all optic zone diffractive multifocal IOL and 25 patients with monofocal IOL. Objective optical quality parameters under 4 mm pupil using Optical Quality Analysis System (OQAS), subjective visual acuity (VA) at 85 cd/m² luminance and questionnaire concerning halo and visual function were assessed.

RESULTS

The multifocal group gained similar objective optical outcomes, such as OQAS values at contrast 100%, 20%, 9%, modulation transfer function cut-off and Strehl ratio, as the monofocal group. Objective scatter index (OSI) was significantly better in the monofocal group. Distance corrected near VA, uncorrected near VA, distance corrected intermediate VA and uncorrected intermediate VA were significantly better in the multifocal group. The difference in uncorrected distance VA and best corrected distance VA between the monofocal and multifocal groups was not significant. Mild halos and glare were reported in both groups and a significant difference between the two groups was not observed; however, moderate glare and halos were reported only in the multifocal group (2/25). There was no significant difference between the two groups when visual function was compared.

CONCLUSIONS

All optic zone diffractive multifocal IOLs provided almost the same objective optical quality as monofocal IOLs did under 4 mm pupil besides good all distance visual performance, but with greater OSI, indicating that implantation provides good optical quality in daytime but with more intraocular scatter light.

TRIAL REGISTRATION NUMBER

NCT02234635, post-results.