Effect of intraocular lens asphericity on vertical coma aberration

The impact of corneal higher-order aberrations on dynamic visual acuity post cataract surgery

Purpose

To explore the influence of corneal higher-order aberrations (HOAs) on dynamic visual acuity (DVA) post cataract surgery.

Methods

A total of 27 patients with 45 eyes following cataract surgery were included in this study. The postoperative monocular object-moving DVA at the velocity of 20, 40, and 80 degrees per second (dps) were examined at 1 month. The total corneal HOAs were measured with Scheimpflug-based corneal topography. The correlation between postoperative DVA and HOAs was analyzed.

Results

Significant difference was shown among DVA at different velocities (P < 0.001). The 20 dps DVA was significantly better than 40 (P < 0.001) and 80 (P < 0.001) dps DVA. No significant difference was observed between 40 and 80 dps DVA (P = 0.420). The vertical coma and the root mean square (RMS) of coma (RMScoma) were statistically correlated with 80 dps DVA (P < 0.05). The vertical trefoil, RMStrefoil and total RMSHOA were statistically correlated with 40 and 80 dps DVA (P < 0.05). The spherical aberration was not significantly associated with postoperative DVA (P > 0.05 for all velocites). The multivariate linear regression model revealed that age was a significant influential factor for 20 dps DVA (P = 0.002), and RMStrefoil (4 mm) and age were significantly associated with 40 and 80 dps DVA (P ≤ 0.01).

Conclusion

The research demonstrated that larger corneal HOAs, especially coma and trefoil aberrations were significantly associated with worse high-speed DVA, but not spherical aberration post cataract surgery.

Comparison of Visual Outcomes and Higher-order Aberrations Between FS-LASIK and SMI-LIKE for Moderate to High Hyperopia: A 2-Year Result

PURPOSE

The aim of the study was to evaluate and compare the long-term visual outcomes and higher-order aberrations (HOAs) between femtosecond laser-assisted in situ keratomileusis (FS-LASIK) and small-incision lenticule intrastromal keratoplasty (SMI-LIKE) in the correction of moderate to high hyperopia.

METHODS

In this study, 16 subjects (20 eyes) underwent FS-LASIK and 7 subjects (10 eyes) underwent SMI-LIKE. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction, mean keratometry (Km), anterior asphericity (Q), and HOAs preoperatively and 2 years postoperatively were obtained in both procedures.

RESULTS

The efficacy indices of the FS-LASIK group and the SMI-LIKE group were 0.85 ± 0.14 and 0.87 ± 0.17, respectively. The safety indices of the FS-LASIK and SMI-LIKE groups were 0.99 ± 0.15 and 1.08 ± 0.24, respectively. No significant difference in safety index or efficacy index was found between the FS-LASIK and SMI-LIKE groups (all P > 0.05). The correlation coefficient of the attempted versus achieved spherical equivalent postoperatively was 0.69 ( P < 0.01) and 0.89 ( P < 0.01) in the FS-LASIK group and SMI-LIKE groups, respectively. The front Km, negative Q value, negative spherical aberrations (SAs), coma, and total HOAs significantly increased postoperatively in the 2 groups ( P < 0.05). The FS-LASIK group had greater changes in Q value and SA postoperatively than the SMI-LIKE group ( P < 0.01).

CONCLUSIONS

SMI-LIKE had similar safety and efficacy to FS-LASIK in the correction of moderate to high hyperopia. However, SMI-LIKE may equip better visual quality postoperatively for its lower Q value and SA changes than FS-LASIK.

The association between ocular biometric components and corneal aberrations

CLINICAL RELEVANCE

Evaluating factors affecting corneal higher-order aberration component has a very important role in interpreting the characteristics of the formed image on the retina.

BACKGROUND

To determine the relationship between ocular biometric components and corneal higher-order aberrations in an elderly population.

METHODS

This report is related to a subsample of the Tehran Geriatric Eye study (TGES), a population-based cross-sectional study that was conducted on individuals aged 60 years and above in Tehran city, Iran using multistage stratified random cluster sampling. All study participants underwent ocular examinations including visual acuity measurement, refraction and slit-lamp biomicroscopy. Anterior segment imaging and corneal aberrometry were performed using Pentacam AXL.

RESULTS

In the present study, 644 eyes of 415 individuals (56.9% female) with mean age of 66.36 ± 4.70 years were evaluated. According to a multiple generalised estimating equation model, the root mean square of total higher-order aberrations was related to age (β = 0.081, p = 0.002), crystalline lens thickness (β = 0.08, p < 0.001), and corneal diameter (β = -0.04, p = 0.014). The root mean square of total coma aberration was directly related to the female sex (β = 0.02, p = 0.05), and crystalline lens thickness (β = 0.06, p < 0.001). There was a direct relationship between the root mean square of third- and fourth-order higher-order aberrations and crystalline lens thickness (p < 0.001). Spherical aberration was directly related to the male sex (β = -0.02, p = 0.004), axial length (β = 0.05, p < 0.001) and central corneal thickness (β = 0.001, p = 0.025), and was inversely related to anterior chamber depth (β = -0.07, p = 0.031) and crystalline lens thickness (β = -0.25, p < 0.001).

CONCLUSION

Ocular biometric components are related to corneal aberrations in the elderly. These factors need to be considered in respect of medical and surgical procedures required for the elderly.

Comparison of visual outcomes of a diffractive trifocal intraocular lens and a refractive bifocal intraocular lens in eyes with axial myopia: a prospective cohort study

Background

To assess and compare the efficacy, safety, accuracy, predictability and visual quality of a diffractive trifocal intraocular lens (IOL) and a refractive rotationally asymmetric bifocal IOL in eyes with axial myopia.

Methods

This prospective cohort study enrolled patients with implantation of the diffractive trifocal IOL or the refractive bifocal IOL. Eyes were divided into four groups according to the IOL implanted and axial length. Manifest refraction, uncorrected and corrected visual acuity at far, intermediate and near distances, prediction error of spherical equivalent (SE), contrast sensitivity and aberrations were evaluated three months after surgery.

Results

In total, 80 eyes of 80 patients were included: 20 eyes in each group. Three months postoperatively, the corrected distance visual acuity of two trifocal groups were significantly better than the axial myopia bifocal group (P = 0.007 and 0.043). There was no significant difference of postoperative SE (P = 0.478), but the SE predictability of the trifocal IOL was better, whether in axial myopia groups (P = 0.015) or in control groups (P = 0.027). The contrast sensitivity was similar among four groups. The total aberration, higher order aberration and trefoil aberration of bifocal groups were significantly higher (all P < 0.001).

Conclusions

The diffractive trifocal IOL and the refractive bifocal IOL both provided good efficacy, accuracy, predictability and safety for eyes with axial myopia. By contrast, the trifocal IOL had a better performance in corrected distance visual acuity and visual quality.

Trial registration

The study was retrospectively registered and posted on clinicaltrials.gov at 12/02/2020 (NCT04265846).

Visual Acuity, Wavefront Aberrations, and Defocus Curves With an Enhanced Monofocal and a Monofocal Intraocular Lens: A Prospective, Randomized Study

PURPOSE

To compare uniocular and binocular visual acuity, wavefront aberrations, and defocus curves using the TECNIS Eyhance (Johnson & Johnson) and RayOne (Rayner) intraocular lenses (IOLs).

METHODS

In this prospective, randomized, comparative study, 50 patients (100 eyes) were randomized to receive the same IOL bilaterally (ClinicalTrials.gov Identifier: NCT04175951). Follow-up visits were at 1 and 3 to 9 months postoperatively. Primary outcome measures were uncorrected distance (UDVA) and uncorrected intermediate (UIVA) visual acuity (logMAR) at 66 cm. Secondary outcome measures were corrected distance (CDVA) and distance-corrected intermediate (DCIVA) visual acuity at 66 cm, manifest refraction, spherical (Z₄⁰) and vertical coma (Z₃^-1) aberrations (total, internal eye, and corneal) at normal pupil size, defocus curves, and Catquest 9SF and Glare and Halos questionnaire on Likert scale (1 = no glare and halos and 4 = continuous).

RESULTS

Uniocular UDVA (P = .02), UIVA (P = .02), and binocular UIVA (P < .01) and uniocular (P = .01) and binocular (P < .01) DCIVA were better with the TECNIS Eyhance IOL at 3 to 9 months. At 3 to 9 months, both uniocular and binocular defocus curves were significantly broader with the TECNIS Eyhance IOL between -0.50 and -3.00 diopters (D). For total and internal eye, there was a statistically but clinically insignificant difference in Z₄⁰ with the TECNIS Eyhance IOL. Rasch scores improved (TECNIS Eyhance: 2.04 ± 1.34 to 2.91 ± 0.81 and RayOne:1.61 ± 1.35 to 2.97 ± 0.16) at 3 to 9 months. Refraction, Z₃^-1, glare, and halos were not different.

CONCLUSIONS

The TECNIS Eyhance IOL provided better DCIVA and broader defocus curves than the RayOne IOL. There was no difference in CDVA or patient-reported outcomes. Although there were some differences in aberrations when measured with normal pupil size, they were not clinically significant. [J Refract Surg. 2022;38(1):10-20.].

Characteristics of Corneal Higher-Order Aberrations in Congenital Ectopia Lentis Patients

Purpose

The purpose of this study was to investigate the characteristics of corneal higher-order aberrations (HOAs) in patients with congenital ectopia lentis (CEL).

Methods

Clinical characteristics and HOAs of 60 patients with CEL and 75 healthy controls at Zhongshan Ophthalmic Center in China were retrospectively analyzed. The Q value and the corneal HOAs in the CEL group and the controls were measured by using Pentacam and compared value between the CEL and control groups. The correlation between HOAs and age was investigated using the Pearson correlation analysis.

Results

The Q value of anterior corneal surface in the CEL group was larger than that in the controls (−0.41 ± 0.17 vs. −0.32 ± 0.13, P = 0.001); the total corneal horizontal coma in the CEL group were larger than that in the controls (0.24 ± 0.18 vs. −0.05 ± 0.14, P < 0.001); both the primary spherical aberrations of the anterior and total corneal surface were lower in the CEL group than that in the controls (for anterior corneal surface: 0.15 ± 0.08 vs. 0.27 ± 0.08 µm, P < 0.001; for total corneal surface: 0.10 ± 0.09 vs. 0.23 ± 0.09 µm, P < 0.001), the anterior and total corneal horizontal coma were negatively associated with age, whereas the anterior and total corneal spherical aberrations were positively associated with age in patients with CEL.

Conclusions

Patients with CEL had higher corneal horizontal coma and lower corneal vertical coma primary spherical aberrations than healthy controls.

Translational Relevance

These findings are informative for the clinical managements in patients with CEL.

Effect of Intraocular Lens Tilt and Decentration on Visual Acuity, Dysphotopsia and Wavefront Aberrations

Tilt and decentration of intraocular lenses (IOL) may occur secondary to a complicated cataract surgery or following an uneventful phacoemulsification. Although up to 2–3° tilt and a 0.2–0.3 mm decentration are common and clinically unnoticed for any design of IOL, larger extent of tilt and decentration has a negative impact on the optical performance and subsequently, the patients’ satisfaction. This negative impact does not affect various types of IOLs equally. In this paper we review the methods of measuring IOL tilt and decentration and focus on the effect of IOL tilt and decentration on visual function, in particular visual acuity, dysphotopsia, and wavefront aberrations. Our review found that the methods to measure the IOL displacement have significantly evolved and the available studies have employed different methods in their measurement, while comparability of these methods is questionable. There has been no universal reference point and axis to measure the IOL displacement between different studies. A remarkably high variety and brands of IOLs are used in various studies and occasionally, opposite results are noticed when two different brands of a same design were compared against another IOL design in two studies. We conclude that <5° of inferotemporal tilt is common in both crystalline lenses and IOLs with a correlation between pre- and postoperative lens tilt. IOL tilt has been noticed more frequently with scleral fixated compared with in-the-bag IOLs. IOL decentration has a greater impact than tilt on reduction of visual acuity. There was no correlation between IOL tilt and decentration and dysphotopsia. The advantages of aspheric IOLs are lost when decentration is >0.5 mm. The effect of IOL displacement on visual function is more pronounced in aberration correcting IOLs compared to spherical and standard non-aberration correcting aspherical IOLs and in multifocal versus monofocal IOLs. Internal coma has been frequently associated with IOL tilt and decentration, and this increases with pupil size. There is no correlation between spherical aberration and IOL tilt or decentration. Although IOL tilt produces significant impact on visual outcome in toric IOLs, these lenses are more sensitive to rotation compared to tilt.

Influence of angle kappa-customized implantation of rotationally asymmetric multifocal intraocular lens on visual quality and patient satisfaction

PURPOSE

To evaluate the visual outcomes and patient satisfaction with angle kappa-customized implantation of SBL-3 (Lenstec, Inc.; +3 D), a rotationally asymmetric multifocal intraocular lens (MIOL).

METHODS

This was a prospective randomized control study. Data from consecutive patients, who underwent bilateral implantation of SBL-3 MIOL from June 2017 to August 2018, were enrolled in the study. One eye of each patient was randomly chosen to receive a horizontal IOL placement (control group), while the other eye received angle kappa-customized placement (design group). The outcomes include uncorrected distance visual acuity (UDVA), uncorrected intermediate visual acuity (UIVA), uncorrected near visual acuity (UNVA), defocus curve, contrast sensitivity, quality of vision and patient satisfaction. The follow-up was 3 months.

RESULTS

The study enrolled 80 eyes of 40 patients. There was no significant difference in mean UDVA, UIVA and UNVA between the two groups. The design group showed significantly better visual acuity at -1.50 D of defocus, based on the defocus curve (p = 0.022), and less vertical coma (p = 0.002) than the control group. No significant differences in contrast sensitivity, modulation transfer function, Strehl ratio and patient satisfaction were found between the two groups.

CONCLUSION

Angle kappa-customized implantation of SBL-3 had little impact on visual outcomes and patient satisfaction, except for a moderate impact on intermediate visual acuity.

Comparison of Outcomes after Phacoemulsification with Two Different Corneal Incision Distances Anterior to the Limbus

Purpose

To compare visual performance and visual quality outcomes after phacoemulsification with two different clear corneal incision (CCI) distances anterior to the limbus in senile cataract patients.

Methods

Retrospective case series. Patients who had undergone phacoemulsification were divided into two groups according to the CCI distances anterior to the limbus. The CCI distances in group A range from 1 mm to 1.5 mm, while those in group B range from 0.5 mm to 1 mm. The visual acuity, refraction, surgically induced astigmatism (SIA), corneal aberrations, anterior segment parameters, and subjective vision quality were evaluated.

Results

This study enrolled 54 eyes, with 27 eyes per group. Both groups had significant improvement in postoperative uncorrected visual acuity (UCVA) and corrected distance visual acuity (CDVA) (P < 0.05). There were no statistically significant between-group differences in postoperative UDVA, CDVA, SIA, corneal aberrations, anterior segment parameters, or VF-QOL questionnaire performance (P > 0.05).

Conclusions

The phacoemulsification with CCI distances ranging from 0.5 mm to 1.5 mm is an effective and safe therapy to senile cataract. The CCI distance anterior to the limbus that ranges from 0.5 mm to 1.5 mm is recommended for routine phacoemulsification.

HIGHER-ORDER ABERRATIONS IN EYES WITH SILICONE OIL TAMPONADE

PURPOSE

To investigate the changes in higher-order aberrations (HOAs) after silicone oil removal and to evaluate their associations with visual acuity.

METHODS

Fifty-nine eyes of 58 patients who underwent SO removal were included. Total, corneal, and internal optic HOAs, and best-corrected visual acuity were measured before and 1 month after SO removal, and changes were compared between phakic and pseudophakic eyes.

RESULTS

Total ocular and internal optic HOAs decreased significantly after SO removal both in pseudophakic (n = 40, all P < 0.001) and phakic eyes (n = 19, P = 0.017, P = 0.004). Preoperative HOAs (P < 0.001) and changes in HOAs (P = 0.006) were greater in pseudophakic eyes than in phakic eyes. Best-corrected visual acuity was significantly improved after SO removal, from 20/105 to 20/78 (P < 0.001) in pseudophakic eyes, whereas there was no difference in phakic eyes (P = 0.714). Preoperative HOAs and the reduction in HOAs after SO removal were greater in best-corrected visual acuity-improved eyes than best-corrected visual acuity-unchanged eyes (P < 0.001).

CONCLUSION

Silicone oil tamponade induced an increase in HOAs, and these increases were greater in pseudophakic eyes than in phakic eyes. Silicone oil may cause additional visual impairments because of HOAs, beyond those caused by retinal diseases, particularly in pseudophakic eyes.

Analysis of corneal higher-order aberrations in cataract patients with high myopia

PURPOSE

To evaluate the differences in corneal higher-order aberrations (HOAs) between cataract patients with high axial myopia and normal cataract patients, and to identify the associated factors.

SETTING

Department of Ophthalmology and Vision Science of the Eye and ENT Hospital of Fudan University, Shanghai, China.

DESIGN

Retrospective case series.

METHODS

Corneal aberrations and axial lengths (ALs) were measured using a rotating Scheimpflug camera (Pentacam) and partial coherence interferometry (IOLMaster) in the high myopia group and the control group.

RESULTS

The study comprised 287 patients (520 eyes). There were 194 eyes in the high myopia group and 326 eyes in the control group. The 5 anterior corneal aberrations-vertical coma, vertical trefoil, horizontal coma, oblique trefoil, and primary spherical aberration-in the high myopia group were 0.07 μm ± 0.38 (SD), -0.11 ± 0.23 μm, 0.07 ± 0.28 μm, -0.02 ± 0.18 μm, and 0.39 ± 0.19 μm, respectively. No negative primary spherical aberrations of the total or anterior corneal surface were found in the high myopia group. Differences between the 2 groups were found in terms of central corneal thickness, astigmatism, primary spherical aberration, vertical coma, and oblique trefoil; however, these differences were not consistent between different age subgroups. Higher-order aberrations were correlated with age. Posterior corneal vertical coma was correlated with AL (Pearson correlation = -0.188, P = .047).

CONCLUSIONS

Negative primary spherical aberrations of the anterior or total corneal surface were not found in the high myopia group. Age showed a strong relationship with HOAs. For cataract patients with high myopia, aspheric intraocular lens implantation is recommended.

Higher order aberrations in a normal adult population

PURPOSE

To determine the distribution of Zernike coefficients and higher order aberrations in a normal population and its relationship with age, gender, biometric components, and spherical equivalent.

METHODS

During the first phase of the Shahroud cohort study, 6311 people of the 40-64-year-old population of Shahroud city were selected through random cluster sampling. A subsample of participants was examined with Zywave aberrometer (The Bausch & Lomb, Rochester, NY) to measure aberrations. Measurements of aberrations were done before cycloplegic refraction, and values generated from a minimum pupil diameter of 5 mm were reported in this analysis.

RESULTS

After applying exclusion criteria, 904 eyes of 577 people were analyzed in this study and mean age in this study was 49.5 ± 5.7 years and 62.9% were female. Mean root-mean-square (RMS) of the third-, fourth-, and fifth-order aberrations was 0.194 μm (95%CI: 0.183 to 0.204), 0.115 μm (95%CI: 0.109 to 0.121), and 0.041 μm (95%CI: 0.039 to 0.043), respectively. Total RMS coma (Z3 (-1,) Z3 (1), Z5 (-1), Z5 (1)), Total RMS trefoil (Z3 (-3,) Z3 (3), Z5 (-3), Z5 (3)), and spherical aberration (Z4 (0)) in the studied population was 0.137 μm (95% CI:0.129-0.145), 0.132 μm (95% CI: 0.123-0.140), and -0.161 μm (95%CI:-0.174 to -0.147), respectively. Mean higher-order Zernike RMS in this study was 0.306 (95% CI: 0.295-0.318) micrometer, and in the multiple model, it significantly correlated with older age and short axial length. The highest amounts of higher-order RMS were observed in hyperopes, and the smallest in emmetropes. Increased nuclear opacity was associated with a significant increase in HO RMS (p < 0.001). Analysis of Zernike coefficients demonstrated that spherical aberration (Z4 (0)) significantly correlated with nuclear cataract only (age-adjusted Coef = 0.37 and p = 0.012).

CONCLUSION

This report is the first to describe the distribution of higher-order aberrations in an Iranian population. Higher-order aberrations in this study were on average higher that those reported in previous studies.

OCULAR WAVEFRONT ABERRATIONS AND OPTICAL QUALITY IN DIABETIC MACULAR EDEMA

PURPOSE

To evaluate optical quality and internal aberrations in patients with diabetic macular edema.

METHODS

In this prospective study, 33 eyes of patients with diabetic macular edema were scanned with a ray-tracing wavefront device. As a control group, wavefront aberrometry was performed in 31 patients. Ocular and internal aberrations and visual quality metrics were evaluated separately to determine whether the source of aberrations was ocular or internal. Main outcome measures included corrected visual acuities, ocular and internal aberrations, Strehl ratio, and modulation transfer function.

RESULTS

There was a statistically significant difference between the groups in internal higher order (HO) root mean square (0.34 ± 0.24 vs. 0.16 ± 0.05), HO Strehl ratio (0.08 ± 0.05 vs. 0.18 ± 0.09), and modulation transfer function (0.29 ± 0.1 vs. 0.4 ± 0.1). There was no statistically significant difference in Strehl ratio and HO root mean square between phakic and pseudophakic patients. Height of cystoid spaces was a significant predictor (P < 0.001) of Strehl ratio. Besides inner and outer segment integrity, HO Strehl ratio significantly determined best-corrected visual acuity.

CONCLUSION

In eyes with macular edema, internal HO wavefront aberrations were greater than in control eyes. This increase in HO wavefront error seems visually relevant. This study results suggest increased intraretinal edema as the source of HO aberrations.

Anterior chamber angle evaluation with ultrasound biomicroscopy and optical coherence tomography in eyes implanted with a Crystalens

This study employs optical coherence tomography (OCT) and ultrasound biomicroscopy (UBM) imaging as well as optical aberrometry to examine correlations between the anterior chamber angle aperture and visual acuity for near vision as well as coma along the horizontal and vertical axes in eyes implanted with an accommodative intraocular lens (Crystalens). A retrospective comparative consecutive case series of 22 eyes of 11 patients (5 males) uneventfully implanted with a Crystalens. Eyes with signs of posterior capsular opacification were excluded. All eyes were examined with 40 MHz UBM (Ellex Eyecubed) and spectral-domain OCT (Zeiss Visante). The angle aperture along the horizontal and vertical meridians was recorded based on the software of the systems. The coma root mean square (RMS) scores for the horizontal and vertical meridians were also recorded with the iTrace aberrometer. The anterior chamber angle was significantly wider along the horizontal axis compared with the vertical axis by UBM (46.37° and 44.20°, respectively) and by OCT (46.79° and 43.58°, respectively) (p = 0.02 in both cases, paired-samples t test). The correlations between the logMAR-converted Jaeger near vision score and the horizontal or vertical angle apertures was not statistically significant. Horizontal coma RMS was significantly inversely correlated with the horizontal angle aperture (r = -0.45, p = 0.03 and r = -0.39, p = 0.04 by OCT and UBM, respectively). Measurement of the horizontal angle aperture by the modalities used may represent an anatomical and clinical predictor of the optical aberrations induced by the Crystalens.

The impact on vision of aspheric to spherical monofocal intraocular lenses in cataract surgery: a systematic review with meta-analysis

PURPOSE

To provide a summary of the impact on vision of an aspheric intraocular lens (IOL) compared with a spherical IOL in cataract surgery.

DESIGN

Systematic review with meta-analysis.

PARTICIPANTS

Patients from published randomized controlled trials (RCTs) of cataract surgery with aspheric compared with spherical monofocal IOL implantation.

METHODS

We systematically searched the peer-reviewed literature in MEDLINE, EMBASE, Web of Science, BIOSIS, and the Cochrane Library according to the Cochrane Collaboration method to identify relevant RCTs. The inclusion criteria were RCTs on cataract surgery comparing the use of aspheric versus spherical IOL implantation that assessed visual acuity, contrast sensitivity, or quality of vision. The effects were calculated as mean differences or standardized mean differences (Hedges' g) and pooled using random-effect models.

MAIN OUTCOME MEASURES

Best-corrected visual acuity (BCVA), contrast sensitivity, and subjective perception of the quality of vision.

RESULTS

Forty-three studies provided data and were included, comprising 2076 eyes implanted with aspheric IOLs and 2034 eyes implanted with spherical IOLs. The BCVA showed a significant difference for aspheric IOLs (-0.01 logarithm of the minimum angle of resolution; 95% confidence interval [CI], -0.02 to -0.00). For contrast sensitivity, a significant advantage for aspheric IOLs was found under photopic and mesopic light conditions (photopic: Hedges' g 0.42, 95% CI 0.24-0.61 (3 cycles per degree [cpd]) to 0.53, 95% CI 0.33-0.73 (12 cpd); mesopic: Hedges' g 0.49, 95% CI 0.23-0.75 (1.5 cpd) to 0.76, 95% CI 0.52-1.00 (18 cpd)). Questionnaires targeting the subjective perception of quality of vision yielded less conclusive results.

CONCLUSIONS

Overall, a patient may achieve better contrast sensitivity with an aspheric IOL than with a spherical IOL, especially under dim light. There was no clinically relevant difference in BCVA between aspheric and spherical IOL implantation. The findings on the subjective perception of visual quality were heterogeneous with no clear result favoring either option.

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.

Internal spherical aberration by ray tracing-type aberrometry in multifocal pseudophakic eyes

PURPOSE

To demonstrate the results of the ray tracing-type aberrometer in measuring spherical aberration (SA) in pseudophakic eyes with monofocal intraocular lens (IOL), aspheric monofocal IOL, or aspheric diffractive multifocal IOL.

METHODS

Total, corneal, and internal SA were measured using iTrace at a 6-mm pupil size in 27 eyes of 27 patients implanted with a monofocal spherical IOL (group 1: Natural, SN60AT), 30 eyes of 30 patients implanted with a monofocal aspheric IOL (group 2: IQ, SN60WF), and 30 eyes of 30 patients implanted with a multifocal aspheric IOL (group 3: ReSTOR, SN6AD1) at 3 months after cataract surgery. We compared the internal SAs of these IOLs in pupil sizes of 3, 4, 5, and 6 mm.

RESULTS

There were no demographic statistically significant differences among the groups. The internal SA of group 1 had a positive value. The internal SA of group 2 was -0.175 ± 0.135 μm in 5-mm pupils and -0.227 ± 0.253 μm in 6-mm pupils. The internal SA of group 3 was -0.072 ± 0.128 μm in 5-mm pupils and -0.173 ± 0.231 μm in 6-mm pupils.

CONCLUSION

Measuring internal SA with iTrace yields relatively accurate results in all types of IOLs with adequate pupil sizes.

Comparison of retinal image quality with spherical and customized aspheric intraocular lenses

We hypothesize that an intraocular lens (IOL) with higher-order aspheric surfaces customized for an individual eye provides improved retinal image quality, despite the misalignments that accompany cataract surgery. To test this hypothesis, ray-tracing eye models were used to investigate 10 designs of mono-focal single lens IOLs with rotationally symmetric spherical, aspheric, and customized surfaces. Retinal image quality of pseudo-phakic eyes using these IOLs together with individual variations in ocular and IOL parameters, are evaluated using a Monte Carlo analysis. We conclude that customized lenses should give improved retinal image quality despite the random errors resulting from IOL insertion.

Fellow-eye comparison of 2 aspheric microincision intraocular lenses and effect of asphericity on visual performance

PURPOSE

To evaluate visual performance and aberrations with aspheric and spherically neutral microincision intraocular lenses (IOLs) and assess the influence of asphericity on visual performance, wavefront aberration, and depth of focus.

SETTING

St. Thomas' Hospital, London, United Kingdom.

DESIGN

Clinical trial and cohort study.

METHODS

In the first study, patients with bilateral cataract were randomized to receive an aspheric Acri.Smart 36A IOL or a spherically neutral Akreos MI60 IOL in the first eye. The other IOL was implanted in the second eye within 3 weeks. Assessments at 3 months were 100% and 9% corrected distance visual acuity (CDVA) and distance-corrected near visual acuity (DCNVA). Aberrations and depth of focus were computed using iTrace software. In the second study, data from the other published study was combined to assess the visual performance, aberration, and depth of focus in groups of spherical, spherically neutral, and negatively aspheric (asphericity -0.17 μm) IOLs.

RESULTS

In part 1, there was no difference in 100% or 9% CDVA, DCNVA, or depth of focus between the 2 microincision IOLs. Total spherical aberration was lower with the aspheric IOL. In part 2, the CDVA and DCNVA were not different between the spherical (n = 44), spherically neutral (n = 32), or aspheric (n = 76) IOLs. Total spherical (P<.01) and vertical coma aberrations decreased with increasing IOL asphericity (P<.01). Depth of focus (4.0 mm pupil) also decreased with increasing asphericity and was significant between the spherical IOL and aspheric IOLs. The DCNVA did not differ between groups.

CONCLUSION

Asphericity of IOLs did not affect distance visual acuity. The difference in depth of focus was significant only between negatively aspheric and spherical IOLs. Asphericity differences up to 20 μm did not influence depth of focus.

Visual outcomes and optical performance of a monofocal intraocular lens and a new-generation multifocal intraocular lens

PURPOSE

To compare visual acuity outcomes and ocular and intraocular optical quality in patients with a monofocal intraocular lens (IOL) or a multifocal IOL with rotational asymmetry.

SETTING

Vissum Corporation, Alicante, Spain.

DESIGN

Comparative case series.

METHODS

Consecutive eyes of cataract patients were divided into 2 groups. One group received a Lentis Mplus LS-312 multifocal IOL and the other, an Acri.Smart 48S monofocal IOL. Distance and near visual acuities, contrast sensitivity, intraocular aberrations (global minus corneal aberrations), and defocus curves were evaluated preoperatively and postoperatively during a 3-month follow-up.

RESULTS

The study evaluated 52 eyes of 29 patients (age range 36 to 87 years); 24 eyes were in multifocal IOL group and 28 eyes, in the monofocal IOL group. Both groups had a significant improvement in uncorrected and corrected distance visual acuities and in distance-corrected near visual acuity (DCNVA) postoperatively (P ≤ .04). The multifocal IOL group had significantly better uncorrected near acuity and DCNVA (Jaeger [J] 5 versus J2) (both P < .01). The defocus curves showed significantly better visual acuities in the multifocal group at several levels of defocus. The multifocal group had significantly higher amounts of postoperative intraocular primary coma (P<.01), especially in eyes with significant IOL tilt, although there were no significant differences in contrast sensitivity between the 2 IOL groups (P ≥ .25).

CONCLUSIONS

The new-generation multifocal IOL restored distance, intermediate, and near visual function after cataract surgery. The optical quality with this type of IOL was particularly affected by IOL tilt and decentration.