Effect of residual ocular spherical aberration on objective and subjective quality of vision in pseudophakic eyes

Risk Factors for Corneal Monochromatic Aberrations and Implications for Multifocal and Extended Depth-of-Focus Intraocular Lens Implantation

PURPOSE

To discuss factors influencing corneal aberrations that might influence the optical quality after intraocular lens (IOL) implantation.

METHODS

PubMed and Scopus were the main resources used to search the medical literature. An extensive search was performed to identify relevant articles concerning factors influencing the level of corneal aberrations as of August 27, 2023. The following keywords were used in various combinations: corneal, aberrations, defocus, astigmatism, spherical aberration, coma, trefoil, quadrafoil, intraocular lens, and IOL.

RESULTS

Conclusive evidence is lacking regarding the correlation between age and changes in corneal aberrations. Patients with astigmatism have greater corneal higher-order aberrations than those with minimal astigmatism, particularly concerning trefoil and coma. Increased levels of corneal higher-order aberrations are noted following contact lens wear, in patients with dry eye disease, and with pterygium. Increased higher-order aberrations have been reported following corneal refractive surgery and for 3 months following trabeculectomy; regarding intraocular lens surgery, the results remain controversial.

CONCLUSIONS

Several factors influence the level of corneal higher-order aberrations. Multifocal and extended depth-of-focus IOLs can share similarities in their optical properties, and the main difference arises in their design and performance with respect to spherical aberration. Preoperative evaluation is critical for proper IOL choice, particularly in corneas with risk of high levels of aberrations. [J Refract Surg. 2024;40(6):e420-e434.].

Effect of larger corneal spherical aberration in improving the near visual acuity of eyes implanted with the TECNIS Symfony

Purpose

To explore the effect of corneal spherical aberration on the visual acuity and visual quality of eyes implanted with the TECNIS Symfony intraocular lens (IOL).

Methods

A total of 43 patients with age-related cataract (60 eyes) undergoing phacoemulsification and TECNIS Symfony IOL implantation were enrolled in this study. The uncorrected distance (UDVA), intermediate (UIVA), near visual acuity (UNVA), corrected distance visual acuity (CDVA), contrast sensitivity, and ocular spherical aberration were recorded 3 months after surgery. Preoperative and postoperative corneal spherical aberration were also measured using the iTrace device. Objective scattering index (OSI), modulation transfer function cut-off frequency (MTF cut-off), and Strehl ratio (SR) were measured by the Optical Quality Analyzing System. Catquest-9SF questionnaire were applied too. Spearman's correlation analysis was used to evaluate the relationship between spherical aberration and visual quality parameters.

Results

Patients were satisfied with their postoperatively visual quality. And the postoperative logMAR UDVA, UIVA, UNVA, and CDVA was 0.05 ± 0.07, 0.04 ± 0.06, 0.15 ± 0.07, and 0.03 ± 0.05, respectively. The mean preoperative corneal spherical aberration was 0.24 ± 0.10 μm, which is the only factor influencing postoperatively UNVA, and it was negatively correlated with UNVA and glare contrast sensitivity under 18 cpd (cycle/degree, cpd) spatial frequency (r = -0.403, -0.300, -0.360; all P < 0.05). Additionally, the greater the residual spherical aberration of the cornea, the better the near vision after operation. The mean postoperative ocular spherical aberration was -0.03 ± 0.07 μm, it was not correlated with visual acuity, contrast sensitivity, and visual quality (all P > 0.05).

Conclusion

Preoperative positive spherical aberration can benefit near vision while decrease contrast sensitivities at high spatial frequencies when implanted with the TECNIS Symfony IOL.

Comparative visual performance of diffractive bifocal and rotationally asymmetric refractive intraocular lenses

We compared the visual performance of a diffractive bifocal intraocular lens (IOL) with + 4.0 D near addition (ZMB00 [Johnson & Johnson Surgical Vision]) and a rotationally asymmetric refractive IOL with + 1.5 D near addition (LS-313 MF15 [Teleon Surgical BV]) 10 weeks after cataract patients' last surgery for bilateral ZMB00 or LS-313 MF15 implantation between 2011 and 2020, with the lenses of each eye implanted within 3 months of each other. The ZMB00 and LS-313 MF15 groups comprised 1326 eyes of 663 patients (age: 67.0 ± 7.8 years; females/males, 518/145) and 448 eyes of 224 patients (73.6 ± 7.0 years; females/males, 125/99), respectively. A linear mixed-effects model using data for both eyes, with strict adjustments for sex, age, subjective refraction spherical equivalent, subjective refraction cylinder, corneal astigmatism, axial length, corneal higher-order aberrations, and pupil diameter, ensured statistical validity. Compared to LS-313 MF15, ZMB00 achieved significantly superior uncorrected near visual acuity, reduced higher-order aberrations (ocular/internal, scaled to a 4-mm pupil; Wavefront_4_post_Ocular_Total Higher-Order Aberration/Third/Fourth/Trefoil/Coma/Tetrafoil/Spherical, Wavefront_4_post_Internal_Astigmatism/Total Higher-Order Aberration/Third/Trefoil/Coma/Tetrafoil/Spherical), and superior distance and near spectacle independence (p < 0.00068, Wald test). Contrast sensitivity, measured without (visual angle of the test target: 6.3°/4.0°/2.5°/1.6°/1.0°/0.7°) or with glare (4.0°/2.5°/1.6°/1.0°/0.7°), was significantly better in the LS-313 MF15 than the ZMB00 group (p < 0.00068, Wald test).

Visual Performance of a Novel Optical Design of a New Multifocal Intraocular Lens

PURPOSE

To evaluate the optical performance and quality of vision of a novel optical design of a new trifocal intraocular lens (IOL) using a proprietary modified algorithm.

METHODS

In this prospective, non-randomized, single-armed, single-center, open-label study, a total of 20 patients (40 eyes) who were candidates for multifocal lens implantation were recruited for implantation with the multifocal Intensity SL IOL (Hanita Lenses). Evaluation performed at 1 and 7 to 10 days and 1 and 3 months after implantation included corrected and uncorrected distance visual acuities at far, intermediate (80 cm), and near (40 cm). Monocular and binocular visual acuities, defocus curves, and contrast sensitivity were measured and questionnaires for grading subjective visual quality, satisfaction, and visual function were provided.

RESULTS

Three months postoperatively, monocular uncorrected visual acuity for distance, intermediate, and near averaged 0.03 ± 0.11, 0.09 ± 0.09, and -0.22 ± 0.09 logMAR, respectively (Snellen 20/21.4, 20/24.6, and 20/12). Corrected monocular visual acuity for distance, intermediate, and near averaged -0.07 ± 0.06, 0.03 ± 0.09, and -0.25 ± 0.07 logMAR (20/17, 20/21.4, and 20/11.2), respectively. Binocular corrected visual acuity for distance, intermediate, and near was -0.1 ± 0.06, -0.02 ± 0.09, and -0.28 ± 0.04 logMAR (20/15.8, 20/19, and 20/10.5), respectively. Contrast sensitivity was similar to the normal population in photopic and mesopic conditions. Defocus curves showed that this IOL provided visual acuity of 20/28.9 or better between a defocus of +1.00 and -3.50 diopters. The Visual Function Index-14 questionnaire showed that patients reported high satisfaction. Patients specifically noted good quality of vision at near and intermediate distances.

CONCLUSIONS

The Intensity SL IOL can provide good quality distance, intermediate, and particularly strong near vision after cataract surgery and independence from spectacles with good patient satisfaction. [J Refract Surg. 2022;38(3):150-157.].

Bias of near-infrared light in evaluation of patients implanted with multifocal intraocular lenses

PURPOSE

To compare visual quality between subjective tests and optical devices using near-infrared (NIR) light in patients implanted with monofocal, multifocal and enlarged depth-of-focus (EDoF) intraocular lenses (IOLs).

METHODS

Cross-sectional study enrolling patients aged between 55 and 75 (axial length between 22 and 25 mm) bilaterally implanted with Tecnis IOLs (Johnson & Johnson) four months previously: 40 patients (80 eyes) with monofocal ZCB00, 41 patients (82 eyes) with bifocal diffractive ZMB00 and 48 patients (96 eyes) with EDoF Symfony. They were examined using subjective and objective tests. The subjective tests comprised visual acuity (VA) with ETDRS charts, contrast sensitivity (CS) with Pelli-Robson and CSV-1000E tests, and clear vision range (CVR). The objective tests using NIR light were performed with the KR-1 W wavefront analyzer and the OQAS.

RESULTS

In the subjective tests, the monofocal group achieved the best outcomes in some of the VA and CS sections, while the bifocal group obtained the worst outcomes in some of the CS sections. In the objective tests, the bifocal group achieved the best results for VA and CS. Discrepancies between pseudoaccommodation range and CVR were found in the bifocal and EDoF groups.

CONCLUSIONS

Assessment of visual quality using NIR light implies greater bias for diffractive lenses than for EDoF lenses. This bias may be even greater with devices using longer light wavelengths or Hartmann-Shack technology. The difference in wavelength between NIR and visible light leads to dimming of near-vision focus and magnification of distance focus.

Objective visual quality one year after toric IOL implantation for correction of moderate and high corneal astigmatism

AIM

To compare the objective visual quality after implantation of a toric intraocular lens (IOL) in order to correct moderate or high corneal astigmatism at the one year postoperative follow-up.

METHODS

From December 2017 to June 2018, 66 patients (90 eyes) with simple age-related cataract with regular corneal astigmatism greater than 1.5 D were enrolled in this prospective self-control study. The patients were implanted with Proming^® toric IOL (model: AT3BH-AT6BH). The subjects were divided into moderate astigmatism group (46 eyes, 1.5-2.5 D) and high astigmatism group (44 eyes, >2.5 D). The uncorrected distance visual acuity, residual astigmatism and axial position of IOL were observed before operation, 3, 6mo and 1y after operation. Modulation transfer function cutoff (MTF cutoff), Strehl ratio (SR), object scatter index (OSI) were observed by OQAS II to evaluate the objective visual quality of patients.

RESULTS

There was no significant difference in UCVA, residual astigmatism, axial deviation, MTF cutoff, SR and OSI between moderate and high astigmatism group (all P>0.05). After 3mo, UCVA, MTF cutoff and SR were significantly increased (all P<0.05), residual astigmatism and OSI were significantly decreased (all P<0.05). After 3mo, all the indexes remained stable.

CONCLUSION

Proming toric IOL can effectively treat age-related cataract patients with moderate-to-high regular corneal astigmatism, correcting corneal astigmatism, improving UCVA, ensuring long-term stability in the capsule, and providing patients with better visual quality.

Pupillodynamics and corneal spherical aberrations in a set of Indian cataract patients and its implications for aberrometric customisation of intraocular lenses

Purpose:

Assessment of pupil diameter in various light conditions and the corresponding corneal spherical aberrations in a cohort of Indian eyes with bilateral senile cataracts and the possible use of this data in aberrometric customization of intraocular lenses (IOLs).

Methods:

In this prospective observational study done at a tertiary eye care centre in India, the selected patients were subjected to measurement of their pupil diameters in scotopic, mesopic, and photopic conditions as well as the corresponding corneal spherical aberrations, using the Sirius Topographer (Costruzione Strumenti Oftalmici, Florence, Italy). Shapiro–Wilk test, Independent t-test, ANOVA with Bonferroni correction on post-hoc testing were used for statistical analysis.

Results:

104 eyes of 52 patients were enrolled for the study. The mean age was 53 ± 11.88 years. The mean scotopic, mesopic, and photopic pupil sizes were 4.37 mm (4.11–4.63 mm), 3.92 mm (3.71 mm–4.15 mm), and 3.37 mm (3.18–3.67 mm), respectively. There was a statistically significant difference (P = <0.001) in the mean corneal spherical aberration measured at the 6 mm zone (0.23 ± 0.02 microns) and at the 4 mm zone (0.06 ± 0.01 microns).

Conclusion:

The mean corneal spherical aberration corresponding to the average mesopic pupil size of our patient population was substantially lower than that of the scotopic pupil size and also less than the amount corrected by most of the negative aspheric IOLs. This perhaps indicates the need for customising IOLs based on the spherical aberrations of cornea at the zone corresponding to the mesopic pupil diameter for optimal residual total postoperative spherical aberrations.

Static and Dynamic Factors Associated With Extended Depth of Focus in Monofocal Intraocular Lenses

PURPOSE

To analyze factors affecting depth of focus (DOF) and near vision functionality in eyes implanted with aspheric monofocal intraocular lenses (IOLs).

METHODS

This prospective study included 111 eyes of 74 patients that underwent phacoemulsification with monofocal IOL implantation. Ninety-one normal eyes were randomized to receive aberration-free (n = 30) or negative-spherical aberration (SA) IOLs (n = 61). Twenty post-hyperopic femto-LASIK eyes received aberration-free IOLs. Corneal higher-order aberrations (SA, coma, trefoil, and corneal asphericity) for a 6 mm pupil were measured by Scheimpflug tomography. Ray-tracing metrics (visual Strehl optical transfer function [VSOTF], effective range of focus [EROF], sphere shift [SS], EROF-SS), pupil size measurements at far and near, and ocular and corneal SA were obtained using ray-tracing aberrometry. Distance-corrected near visual acuity (DCNVA) and subjective defocus curves up to ±4.0 diopters were evaluated.

RESULTS

Multivariable logistic regression found corneal profile and IOL type to be determinants of extended DOF with monofocal IOLs. The aberration-free IOL group showed significantly better DCNVA and higher total SA than the negative-SA group. Post-hyperopic LASIK eyes showed significantly better DCNVA; higher negative SA, coma, and Q value (P < .05), and smaller pupil size (P = .05) than normal eyes implanted with aberration-free IOLs.

CONCLUSION

Corneal profile and type of IOL implanted were the most important factors influencing near vision functionality with aspheric monofocal IOLs. Higher positive SA in the aberration-free group potentially led to better DCNVA than the negative-SA group in normal eyes. Hyperprolate corneas had better DOF curves and DCNVA than normal corneas. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Individually Customized IOL Versus Standard Spherical Aberration-Correcting IOL

PURPOSE

To compare the visual performance of an individually customized intraocular lens (IOL) versus a standard spherical aberration-correcting IOL.

METHODS

In this prospective comparative study, 74 eyes of 60 patients scheduled for cataract surgery were randomized in a 2:1 ratio to receive either an individually customized IOL (; HumanOptics AG, Erlangen, Germany; customized group) or an aspheric IOL with a standard correction of spherical aberration (SA) (Tecnis ZCB00; Johnson & Johnson Vision Surgical, Inc., Santa Ana, CA; standardized group). In the customized group, IOL calculation was based on a minimum of a merit function that contained terms representing residual refraction, residual SA, and modulation transfer function. In the standardized group, the IOL was calculated with a routine procedure using the Holladay formula and had a standard SA correction of -0.27 µm. Refraction, visual acuity (far, intermediate, near), photopic and mesopic contrast sensitivity, defocus curve, corneal and ocular spherical aberration, and pupil size were measured 4 weeks and 3 months postoperatively.

RESULTS

The customized group comprised 48 eyes of 37 patients and the standardized group 26 eyes of 23 patients. At 3 months, mean total ocular SA (5 mm) was 0.04 ± 0.06 µm in the customized group and -0.01 ± 0.05 µm in the standardized group. Uncorrected distance visual acuity and distance-corrected near visual acuity were statistically significantly better in the customized group. Contrast sensitivity testing yielded significantly better results in the customized group under photopic and mesopic conditions for almost all spatial frequencies. Compared to the standardized group, the defocus curve of the customized group showed a wider plateau surrounding the distance focal point.

CONCLUSIONS

With the implantation of an individually optimized aspheric IOL visual performance, especially contrast sensitivity, can be significantly improved compared to a standard aberration-correcting IOL. [J Refract Surg. 2019;35(9):565-574.].

Objective optical quality in eyes with customized selection of aspheric intraocular lens implantation

BACKGROUND

To compare the postoperative optical quality in eyes with customized selection and random selection of aspheric intraocular lens (IOL) implantation.

METHODS

A prospective, nonrandomized study was implemented in adult cataract patients who underwent unilateral phacoemulsification with aspheric IOL implantation. Patients were allocated into two treatment groups: a customized group and a control group. In the customized group, the aspheric IOL selection was based on the corneal spherical aberration to enable the postoperative target ocular spherical aberration closest to zero; in the control group, the aspheric IOLs were chosen using a random strategy. Primary outcome measurements included the following objective optical quality assessments: higher-order aberrations obtained by a Hartmann-shack aberrometer at 4 mm and 6 mm pupil diameters; objective scatter index (OSI), modulation transfer function (MTF) cut-off, Strehl ratio (SR) and a simulated contrast visual acuity-optical quality analysis system value (OV) obtained by a double-pass system with a 4-mm aperture. Subjective visual acuity was measured as secondary outcome. All the patients were followed up for 3 months.

RESULTS

Eighty-four patients in the customized group and 78 patients in the control group were evaluated. There was no significant difference in postoperative visual acuity between the two groups (P > 0.05). Significantly less ocular higher-order aberrations were shown in the customized group (P < 0.05). No significant difference was shown in OSI, MTF cut-off, SR and OV between the two groups (P > 0.05).

CONCLUSIONS

Although customized selection of aspheric IOL implantation showed less postoperative ocular aberrations, it performed similarly to random selection of aspheric IOL implantation in terms of postoperative visual acuity, simulated contrast visual acuity, intraocular scatter, modulation transfer function and Strehl ratio.

TRIAL REGISTRATION

Retrospectively registered on 07/06/2019. Registration number: ChiCTR1900024356 .

Effect of Spherical Aberration on the Optical Quality after Implantation of Two Different Aspherical Intraocular Lenses

PURPOSE

To compare the effect of spherical aberration on optical quality in eyes with two different aspherical intraocular lenses.

METHODS

120 eyes of 60 patients underwent phacoemulsification. In patients' eyes, an aberration-free IOL (Aspira-aA; Human Optics) or an aberration-correcting aspherical IOL (Tecnis ZCB00; Abott Medical Optics) was randomly implanted. After surgery, contrast sensitivity and wavefront measurements as well as tilt and decentration measurements were performed.

RESULTS

Contrast sensitivity was significantly higher in eyes with Aspira lens under mesopic conditions with 12 cycles per degree (CPD) and under photopic conditions with 18 CPD (p = 0.02). Wavefront measurements showed a higher total spherical aberration with a minimal pupil size of 4 mm in the Aspira group (0.05 ± 0.03) than in the Tecnis group (0.03 ± 0.02) (p = 0.001). Strehl ratio was higher in eyes with Tecnis (0.28 ± 0.17) with a minimal pupil size larger than 5 mm than that with Aspira (0.16 ± 0.14) (p = 0.04). In pupils with a minimum diameter of 4 mm spherical aberration had a significant effect on Strehl ratio, but not in pupils with a diameter less than 4 mm.

CONCLUSIONS

Optical quality was better in eyes with the aberration-correcting Tecnis IOL when pupils were large. In contrast, this could not be shown in eyes with pupils under 4 mm or larger. This trial is registered with Clinicaltrials.gov NCT03224728.

Comparative study of visual function and ocular aberrations of two different one-piece designed hydrophilic acrylic intraocular lens

PURPOSE

To determine whether the aspherical IOL, Tecnis ZCB00, can improve the visual quality by measuring visual acuity, wavefront aberrations, and contrast sensitivity.

METHODS

It was a retrospective case series. Patients who underwent phacoemulsification cataract surgery were divided into two groups. One group (Group TC) was implanted with one-piece aspherical acrylic IOL (Tecnis ZCB00, AMO); the other (Group SA) was implanted with one-piece spherical acrylic IOL (Sensar AAB00, AMO). Eighty-eight eyes were selected into this study, among them 43 eyes in 26 male cases and 45 eyes in 29 female cases. Thirty-six eyes in 23 cases were in Group TC, and 52 eyes in 32 cases were in Group SA. Three months postoperatively, aberrations were analyzed with i-Trace visual function analyzer (Tracy Technologies, USA). Contrast sensitivities were measured with Takaci-CGT-1000 contrast glare tester (Seiko, Japan).

RESULTS

All the 88 eyes underwent phacoemulsification with intraocular lens implantation, without complications during or after surgery. Three months postoperatively, the uncorrected vision acuity in Group TC was significantly better than in Group SA (P = 0.007). At the pupil size of 5.0 mm, higher-order aberrations in Group TC were significantly higher than in Group SA (P = 0.02), especially the spherical aberration (Z ₄⁰ ) (P < 0.001); at the pupil size of 4.0 mm, Z ₄⁰ in Group SA was statistically higher than in Group TC (P < 0.001); at the pupil size of 3.0 mm, higher-order aberrations such as coma (Z ₃^-1,1 ) and trefoil aberration (Z ₃^-3,3 ) in Group SA were obviously higher than in Group TC (P = 0.01). In the low spatial frequency, the contrast sensitivity and the glare sensitivity in Group TC were significantly higher than in Group SA (P < 0.05).

CONCLUSIONS

By the short-term follow-up (3 months), the aspherical acrylic IOL can reduce the higher-order aberrations (especially the spherical aberration) and increase the contrast sensitivity to improve the visual performance.

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.

Effect of the pigment-free optical zone diameter of decorative tinted soft contact lenses on visual function

AIMS

We investigated changes in visual function after wearing decorative tinted soft contact lenses with different pigment-free optical zone diameters.

METHODS

A prospective study was performed in 30 eyes of 30 healthy volunteers. Best-corrected visual acuity (BCVA), ocular higher-order aberrations (HOAs), modulation transfer function (MTF), Strehl ratio and contrast sensitivity were evaluated after wearing clear lens and tinted lenses with different pigment-free optical zone diameters (4, 5 and 6 mm).

RESULTS

BCVA decreased from 0.00 logMAR after wearing a clear lens to 0.04±0.04 logMAR after wearing 4 mm optical zone lens (p<0.001). As the optical zone diameter decreased, ocular aberrations were induced. Total HOAs, coma aberration and secondary astigmatism showed significant difference between clear lens and 5 or 4 mm optical zone lenses (p<0.050). Spherical aberration and trefoil showed significant difference between clear lens and 4 mm optical zone lens (p<0.050). The results for Strehl ratio revealed poorer optical quality for both 5 and 4 mm optical zone lens (both p=0.002). The entire ocular MTF was significantly different, corresponding to the decreased optical zone diameter. The HOAs showed a correlation with the blocked pupil covered by the tinted part (r=0.435, p<0.001). In photopic and mesopic conditions, the contrast sensitivity decreased significantly with the reduced pigment-free optical zone diameters.

CONCLUSION

Decorative tinted contact lenses significantly increased ocular aberrations and decreased optical quality and contrast sensitivity, as the pigment-free optical zone diameter decreased. Therefore, consumers of tinted lenses should be informed about the possible disturbance in visual function.

TRIAL REGISTRATION NUMBER

NCT02537275.

Clinical study of customized aspherical intraocular lens implants

AIM

To compare if there is an improvement in visual functions with age-related cataracts between patients receiving a aspherical intraocular lens (IOL) based on corneal wavefront aberration and patients randomly assigned lenses.

METHODS

A total of 124 eyes of 124 patients with age-related cataracts were placed in experimental group and a group receiving randomly assigned (RA) lenses. The experimental group was undergone Pentacam corneal spherical aberration measurement before surgery; the targeted range for residual total spherical aberration after surgery was set to 0-0.3 µm. Patients with a corneal spherical aberration <0.3 µm were implanted with a zero-spherical aberration advanced optics (AO) aspherical IOL and patients with an aberration ≥0.3 µm received a Tecnis Z9003 aspherical lens in experimental group. RA patients were randomly implanted with an AO lens or a Tecnis Z9003 lens. Three months after surgery total spherical aberration, photopic/mesopic contrast sensitivities, photopic/mesopic with glare contrast sensitivities, and logMAR vision were measured.

RESULTS

Statistical analysis on logMAR vision showed no significant difference between two groups (P=0.413). The post-surgical total spherical aberration was 0.126±0.097 µm and 0.152±0.151 µm in the experimental and RA groups, respectively (P=0.12). The mesopic contrast sensitivities at spatial frequencies of 6, 12 and 18 c/d in the experimental group were significantly higher than of the RA group (P=0.00; P=0.04; P=0.02). The mesopic with glare contrast sensitivity in the experimental group at a spatial frequency of 18 c/d was also significantly higher vs the RA group (P=0.01).

CONCLUSION

Pre-surgical corneal spherical aberration measurement in cataract patients followed by customized selection of aspherical IOL implants improved mesopic contrast sensitivities at high spatial frequencies, and thus is a superior strategy compared to the random selection of aspherical IOL implants.

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.

Double-pass system assessing the optical quality of pseudophakic eyes

PURPOSE

To compare the optical quality measurements obtained from the double-pass system and ocular aberrations, subjective visual acuity, and contrast sensitivity score in pseudophakic eyes.

METHODS

Three months after cataract surgery, modulation transfer function (MTF) cutoff frequency, Strehl ratio, objective scatter index, and objective pseudoaccommodation obtained from the double-pass system were compared with total aberration, higher-order aberration, and spherical aberration obtained from ray-tracing aberrometer. In addition, parameters of the double-pass system were compared with subjective visual acuity and the contrast sensitivity score.

RESULTS

Forty eyes of 40 patients were included. The MTF cutoff frequency and Strehl ratio were negatively correlated with total aberration (r = -0.503, p = 0.003; r = -0.509, p = 0.003, respectively) and subjective visual acuity (r = -0.453, p = 0.007; r = -0.354, p = 0.040, respectively). The objective scatter index was positively correlated with total aberration (r = 0.451, p = 0.024) and subjective visual acuity (r = 0.516, p = 0.008). The MTF cutoff frequency showed a correlation with contrast sensitivity score under photopic and mesopic conditions.

CONCLUSIONS

Optical quality parameters obtained from the double-pass system were correlated with ocular aberrations, subjective visual acuity, and contrast sensitivity score in pseudophakic eyes.

Comparison of visual quality between aspheric and spherical IOLs

PURPOSE

To determine if aspheric intraocular lens (IOL) implantation produces the same degree of postoperative ocular aberration and contrast sensitivity as spherical IOL implantation.

METHODS

In this randomized prospective comparative study, 60 eyes of 30 cataract surgery patients were randomly assigned to receive a spherical IOL (Rayner 620H) in one eye and an aspheric IOL (Rayner 920H) in the contralateral eye. All patients were examined at 1 month postoperatively. Primary outcomes of contrast sensitivity and ocular wavefront higher order aberrations (HOAs) were assessed.

RESULTS

Aspheric IOLs (median total HOAs 0.26 root mean square [RMS]; range 0.13-0.82 RMS) produced significantly lower total HOAs than spherical IOLs (median total HOAs 0.34 RMS; range 0.18-1.08 RMS; p<0.05). Contrast sensitivity was significantly better with aspheric IOLs (median contrast sensitivity 1.8 log units; range 1.35-1.8 log units) than with spherical IOLs (median contrast sensitivity 1.65 log units; range 1.35-1.8 log units; p<0.05).

CONCLUSIONS

When compared with a structurally (platform and material) similar spherical IOL (Rayner 620H), aspheric IOLs (Rayner 920H) appear to significantly reduce HOAs and yield better levels of contrast sensitivity under photopic conditions.

Comparison of optical quality parameters and ocular aberrations after wavefront-guided laser in-situ keratomileusis versus wavefront-guided laser epithelial keratomileusis for myopia

BACKGROUND

To compare optical quality, ocular scattering, and higher-order aberrations (HOAs) after laser in-situ keratomileusis (LASIK) versus laser epithelial keratomileusis (LASEK).

METHODS

A total of 47 eyes from 47 participants who had undergone LASIK (group I) or LASEK (group II) procedure at least 6 months prior were enrolled. Ocular aberrations and modulation transfer function (MTF) values measured using iTrace, a ray-tracing type aberrometer, were compared to MTF (modulation transfer function) cut-off values, Strehl ratio, and objective indices of scattering obtained using the Objective Quality Analysis System II (OQAS II).

RESULTS

There was no significant correlation between the postoperative optical quality parameters and the HOAs between both groups. In group I, the MTF cut-off value was significantly correlated with cylinder refraction (p = 0.037), and the objective scattering index (OSI) was positively correlated with spherical equivalent (p = 0.023). In group II, there was a statistically significant correlation between the OSI and achieved refractive correction (p = 0.001). Regression analysis showed that the OSI was the most significant predictor of MTF cut-off values after refractive surgery. Additionally, MTF values measured by OQAS were significantly lower than those measured by iTrace without correlation.

CONCLUSION

Optical quality after refractive surgery may be influenced by not only ocular aberrations but also by scattering. Even though the accuracies of the machines used in this study to measure optical quality have yet to be proven, this study showed limited correlation among the values measured using the two different machines after refractive surgery. Therefore, for more generalized evaluation of visual function after refractive surgery, more advanced optical devices still need to be developed.

[Use of "mix-and-match" aspheric intraocular lenses in cataract surgery to enhance depth of field and stereoscopic performance]

INTRODUCTION

One of the remaining challenges in cataract surgery is to compensate for lost accommodative function. The purpose of our study is to evaluate reading ability with a combination of two different aspheric intraocular lenses.

PATIENTS AND METHODS

This retrospective study included 40 eyes (20 patients). The control group (28 eyes, 14 patients) received two negative aspheric intraocular lenses (Acrismart 36A(®), Carl Zeiss Meditec), while the aspheric-optimized group (12 eyes, six patients) received an AcriSmart 36A(®) in the dominant eye and a zero-aspheric intraocular lens (Acrismart 46 LC(®), Carl Zeiss Meditec) in the fellow eye. Patients with corneal asphericity between 0.15 and 0.30 μm and a bilateral monocular postoperative visual acuity of at least 20/20 were eligible for inclusion. Uncorrected and best corrected visual acuity was measured for near, intermediate and distance vision. Corneal and total higher-order aberrations, monocular and binocular defocus curve, and stereoscopic performance were assessed.

RESULTS

Postoperative spherical equivalent and best corrected distance visual acuity were not significantly different between the two groups (P=0.11 and P=0.82 respectively). However, the aspheric-optimized group (36A(®)/46 LC(®)) exhibited better near and intermediate visual acuity (P<0.05), and better stereoscopic vision (P=0.027).

DISCUSSION

The depth of field results in pseudophakes implanted with "mix-and-match" aspheric lenses demonstrates that the binocular combination of two different aspheric profiles seems to improve near vision without affecting stereoscopic vision.

Visual and aberrometric outcomes in eyes with an angle-supported phakic intraocular lens

PURPOSE

To evaluate the postoperative changes in spherical aberration and the point-spread function (PSF) induced by the implantation of a new angle-supported phakic intraocular lens (pIOL).

SETTING

Department of Ophthalmology, St. Bassiano Hospital, Bassano del Grappa, Italy.

DESIGN

Prospective nonrandomized cohort study.

METHODS

Eyes with high myopia had implantation of an Acrysof Cachet angle-supported pIOL. Preoperative and postoperative total spherical aberration and PSF were measured using a Luneau 80 Wave+ wavefront aberrometer (high-resolution Hartmann-Shack technology) at a fixed entrance pupil scan size of 5.0 mm under pharmacologic mydriasis. Preoperative and postoperative data were analyzed and compared using the Student t test.

RESULTS

Thirty-five eyes of 18 patients were included in the statistical analysis. The Student t test for paired data (95% confidence interval) showed a statistically significant difference between preoperative data and postoperative data. The mean preoperative total spherical aberration Z(4,0) was -0.001 μm ± 0.076 (SD) preoperatively and -0.13 ± 0.11 μm postoperatively (P≤.05). The mean PSF was 0.28 ± 0.15 preoperatively and 0.34 ± 0.16 postoperatively (P<.05).

CONCLUSION

Implantation of the angle-supported pIOL in eyes with high myopia improved the quality of vision, inducing negative spherical aberration and increasing the PSF under mesopic conditions.

Effect of interaction of macroaberrations and scattered light on objective quality of vision in pseudophakic eyes with aspheric monofocal intraocular lenses

PURPOSE

To assess the impact of wavefront ocular aberrations on objective vision quality and depth of focus in pseudophakic patients.

SETTING

University Hospital Bretonneau of Tours, Francois Rabelais Medicine Faculty of Tours, France.

DESIGN

Cohort study.

METHODS

Consecutive eyes having implantation of an aspheric monofocal intraocular lens (IOL) (Acri.Smart) were studied. Aberrometry measurements were performed under mesopic conditions with a 6.0 mm pupil using a Wavescan aberrometer. Objective evaluation of optical vision quality was performed using the Optical Quality Analysis System II. The 3 measurements were the modulation transfer function values (MTF cutoff); objective depth of focus, which was computed as the focus range at which Strehl ratio did not fall below 50% of the maximum; and the objective scatter index.

RESULTS

Fifty-four eyes (30 patients) were enrolled. Six months postoperatively, MTF cutoff values were increased with decreasing total ocular spherical aberration, ocular trefoil, and 2nd-order astigmatism (P<.05). Objective depth of focus was positively correlated with 2nd-order astigmatism (r(2) = 0.171, P<.001) and total spherical aberration (r(2) = 0.091, P=.028). Objective scatter was more beneficial for depth of focus, with a significantly positive correlation with this parameter (r(2) = 0.28, P=.002), than compromising of optical quality (no significant correlation with MTF measurements in same multiple regression analysis).

CONCLUSION

Three ocular aberrations (2nd-order astigmatism, trefoil, spherical aberration) seemed to interact with objective contrast sensitivity and depth of focus, whereas residual spherical aberration exerted opposite effects on image quality in individual patients.