Ocular aberrations and visual performance with an aspheric single-piece intraocular lens: Contralateral comparative study

Spherical aberrations and their role in modern ophthalmology

Spherical aberration is an imperfection of the optical system of the human eye. The role of spherical aberration of the human eye in the quality of vision and pseudoaccommodation is reviewed. Spherical aberration is an imperfection of the optical system of the human eye. In most cases, due to well-developed neuroadaptation, it is insignificant for the perception of the image. Nevertheless, its role in modern ophthalmology is far from straightforward. On the one hand, there are clinical scenarios in which an excess of spherical aberration degrades the retinal image and leads to a high dissatisfaction rate among patients.©Recently, there is a growing interest in the modulation of spherical aberration in the clinical setting. Modern intraocular lenses as well as laser refractive procedures are aimed at interfering with spherical aberrations of the optical system in order to increase range of pseudoaccommodation. Here, we review the role of spherical aberration of the human eye in the quality of vision and pseudoaccommodation.

Characteristics and influencing factors of corneal higher-order aberrations in patients with cataract

PURPOSE

To observe the distribution characteristics of corneal higher-order aberrations (HOAs) in cataract patients, and analyze the relationship of HOAs with patients' age and ocular biometric parameters.

METHODS

This retrospective study reviews the patients with cataract in Wuhan Aier Eye Department from January to August 2022. Root mean square (RMS) of the total HOA (tHOA), spherical aberration (SA), coma and trefoil aberration of the anterior cornea at central 4 and 6 mm optic zone were measured by the Wavefront Aberrometer (OPD-Scan III; Nidek Inc, Tokyo, Japan). The biometric parameters including axial length (AL), keratometry (K), central corneal thickness (CCT) and lens thickness (LT) were measured by swept-source coherence laser interferometry (OA-2000; TOMEY Corp, Aichi, Japan). Subgroup analyses and multiple linear regression analyses were used to determine whether HOAs were associated with age and ocular biometric parameters.

RESULTS

A total of 976 patients (976 eyes) were included, averagely aged 65 years. At central 4 and 6 mm optic zone, the mean RMS of tHOA were respectively 0.20 and 0.65 μm, the SA were 0.06 and 0.30 μm, the coma aberration were 0.11 and 0.35 μm, and the trefoil aberration were 0.12 and 0.30 μm. The tHOA decreased with age until 60 years and then started to increase afterwards. The tHOA, coma and trefoil aberration increased with corneal astigmatism. The tHOA, SA, and coma aberration differ among different AL groups, and emmetropes had the smallest tHOA, SA, and coma aberration.

CONCLUSIONS

With increasing age, the value of tHOA decrease first and started increasing at 60 years. The trends of corneal HOAs are consistent with corneal low-order aberrations. The values of tHOA, SA and coma aberration were the smallest in emmetropic eyes.

Visual outcomes and safety of the TECNIS Symfony intraocular lens: results of a pivotal clinical trial

Randomized comparison of the TECNIS Symfony (ZXR00) and the TECNIS 1-piece monofocal (ZCB00) intraocular lenses in cataract surgery demonstrates improved intermediate and near vision with TECNIS Symfony.

To compare the effectiveness and safety of the TECNIS Symfony intraocular lens (IOL; ZXR00) with the TECNIS 1-piece monofocal IOL (ZCB00).

Distribution of corneal spherical aberration in a Tanzanian population

Purpose

To investigate the distribution of corneal spherical aberration (SA) in Tanzanian people of African descent, and to examine the correlation between corneal SA and ocular parameters.

Design

Cross-sectional population-based study.

Methods

Residents aged 40 years and older in three villages in the Mkuranga district in Tanzania were enlisted as study participants. Corneal higher-order aberrations (HOAs) for the right eye were measured with a wavefront analyzer (KR-1W, Topcon) and calculated for the central 6.0-mm zone. Corneal curvature radius (CR), corneal astigmatism, and axial length (AL) were also measured and their correlation with corneal SA was assessed.

Results

The right eyes of 657 participants (336 male, 321 female) were analyzed. The mean age of the subjects was 57.2 ± 10.3 years (mean ± SD). The mean corneal SA (Zernike spherical aberration coefficient C₄⁰) was 0.188 ± 0.095 μm (-0.242 to 0.613). The SAs in about three-quarters of all subjects were between 0.10 and 0.30 μm. The root mean squares of total corneal HOAs and the third- and fourth-order aberrations were 0.629 ± 0.250 μm, 0.539 ± 0.236 μm, and 0.269 ± 0.110 μm, respectively. Corneal SA showed weak significant correlations with CR (Spearman’s rank correlation coefficient, r = -0.177, p < 0.001), corneal astigmatism (r = -0.142, p < 0.001), AL (r = -0.168, p < 0.001), and age (r = -0.085, p < 0.05).

Conclusions

This finding may be beneficial for selecting aspheric intraocular lens in this population.

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 .

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.

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.

A comparative study on visual and optical performance of Akreos AO and Kontur AB IOLs after phacoemulsification cataract surgery

PURPOSE

Akreos AO and Kontur AB are two commonly used intraocular lenses (IOLs) in Iran. This study was designed to evaluate the visual performance of these lenses.

METHODS

In a comparative interventional study, 35 patients (70 eyes) were recruited, and each IOL was implanted in one eye of the patients, randomly. Best corrected visual acuity (BCVA), contrast sensitivity, aberrometric analysis, and depth of focus were evaluated 1 month and 3 months postoperatively. A visual quality questionnaire was also filled for each eye, and the results were compared.

RESULTS

Mean age of the patients was 60.97 ± 7.00 years. BCVA was not significantly different between the two eyes, before, 1 month, and 3 months postoperatively (p > 0.05 for all). Photopic and mesopic contrast sensitivity was not different between the two lenses instead of photopic 18 cycles per degree, 3 months postoperatively and in mesopic 6 cycles per degree 1 month postoperatively (p = 0.034 and p = 0.002, respectively). Aberrometric factors including HoRMS, Total RMS, and Higher order without Z(4,0) were not significantly different between the two lenses (p > 0.05 for all), but they were slightly lower for Akreos AO. Post-operative distance-corrected visual acuity for intermediate and near vision were not different between the two groups (p > 0.05, respectively).

CONCLUSION

Visual performance of Akreos AO and Kontur AB is similar. However, contrast sensitivity and aberrometric parameters are slightly better for Akreos AO IOL.

High order aberration and straylight evaluation after cataract surgery with implantation of an aspheric, aberration correcting monofocal intraocular lens

AIM

To evaluate the quality of vision in respect to high order aberrations and straylight perception after implantation of an aspheric, aberration correcting, monofocal intraocular lens (IOL).

METHODS

Twenty-one patients (34 eyes) aged 50 to 83y underwent cataract surgery with implantation of an aspheric, aberration correcting IOL (Tecnis ZCB00, Abbott Medical Optics). Three months after surgery they were examined for uncorrected (UDVA) and corrected distance visual acuity (CDVA), contrast sensitivity (CS) under photopic and mesopic conditions with and without glare source, ocular high order aberrations (HOA, Zywave II) and retinal straylight (C-Quant).

RESULTS

Postoperatively, patients achieved a postoperative CDVA of 0.0 logMAR or better in 97.1% of eyes. Mean values of high order abberations were +0.02±0.27 (primary coma components) and -0.04±0.16 (spherical aberration term). Straylight values of the C-Quant were 1.35±0.44 log which is within normal range of age matched phakic patients. The CS measurements under mesopic and photopic conditions in combination with and without glare did not show any statistical significance in the patient group observed (P≥0.28).

CONCLUSION

The implantation of an aspherical aberration correcting monofocal IOL after cataract surgery resulted in very low residual higher order aberration (HOA) and normal straylight.

The Optical Performance of Spherical and Aspheric Intraocular Lenses in Pediatric Eyes: A Comparative Study

PURPOSE

To compare the optical performance of aspheric intraocular lenses (IOLs) designed to correct the corneal spherical aberration versus spherical IOLs in pediatric eyes after cataract surgery.

METHODS

In this prospective study, 40 eyes of patients 6 to 16 years old with developmental cataract were randomly assigned to receive a spherical IOL or an aspheric IOL after pediatric cataract surgery. At 3 months postoperatively, the outcomes compared between the two groups were best-corrected visual acuity, contrast sensitivity, and wavefront aberrometry.

RESULTS

The mean best-corrected visual acuity was 0.32 ± 0.19 logMAR in the spherical IOL group and 0.28 ± 0.16 logMAR in the aspheric IOL group (P = .179). The aspheric IOL group showed better contrast sensitivity at 1.5, 3, and 6 cycles per degree than the spherical IOL group (P < .05). Total ocular aberrations, higher-order aberrations, and spherical aberrations were significantly lower in the aspheric IOL group (P < .05).

CONCLUSIONS

The results suggest that aspheric IOLs compensate for the spherical aberration of pediatric eyes. In comparison to spherical IOLs, eyes with aspheric IOLs had decreased ocular aberrations, particularly spherical aberration, which contributed to better contrast sensitivity in these eyes. Further studies are required to evaluate the role of aspheric IOLs in children.

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.

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.

Change in efficiency of aspheric intraocular lenses based on pupil diameter

PURPOSE

To measure the effect of spherical aberration correction by aspheric intraocular lenses (IOLs) based on pupil diameter, and to determine the minimum pupil diameter for each aspheric IOL.

DESIGN

Retrospective cross-sectional study.

METHODS

Eight-six patients (169 eyes) who were implanted with a HOYA AF-1 NY-60 (HOYA Corporation) or Tecnis ZCB00 1-piece IOL (Abbott Medical Optics Inc) were enrolled. Ocular, corneal, and internal spherical aberrations were measured at the 1-month postoperative visit using the Wavefront Analyzer KR-1W (Topcon). Minimum pupil diameter, which is required for each aspheric IOL to be effective, was calculated using a regression equation.

RESULTS

The mean value of internal spherical aberration of the Tecnis ZCB00 group (-0.09 ± 0.094 μm) was lower than that of the HOYA NY-60 group (-0.05 ± 0.072 μm) (P = .005). The original negative spherical aberrations of the HOYA NY-60 (-0.18 μm) were measured at a pupil diameter of 5.6 mm, and for the Tecnis ZCB00 (-0.27 μm) at a pupil diameter of 6.1 mm. The aspheric IOL efficiency dropped to 0% when the pupil diameter was 3.47 mm for the Tecnis ZCB00 group and 3.71 mm for the HOYA NY-60 group.

CONCLUSIONS

When the pupil diameters of patients are smaller than 3.4 mm for the Tecnis ZCB00 and 3.7 mm for the HOYA NY-60, the spherical aberration correction using these aspheric IOLs seems to be ineffective. Approximately 10% of the eyes showed smaller pupil size than the minimum effective diameter under mesopic conditions.

Visual and optical performance of eyes with different corneal spherical aberration implanted with aspheric intraocular lens

AIM

To compare the visual and optical performance of eyes with different corneal spherical aberration (SA) implanted with spherical aberration-free intraocular lens (IOLs).

METHODS

Thirty-six patients with different corneal SA had phacoemulsification with implantation of spherical aberration-free IOLs. Patients were divided into 3 groups according to the value of preoperative corneal SA. Eyes with corneal SA <0.10µm were assigned to group A, those with 0.10 ≤corneal SA <0.20µm to Group B, and those with 0.20≤ corneal SA <0.35µm to Group C. Best-corrected visual acuity (BCVA), contrast sensitivity, corneal SA, total ocular aberrations, and depth of focus were recorded 3 months postoperatively. Distance-corrected near and intermediate visual acuity was studied to measure depth of focus.

RESULTS

BCVA and contrast sensitivity were similar between groups. There were no significant differences in distance-corrected near or intermediate visual acuity. Corneal SA was similar before and 3 months after surgery in the 3 groups. With a 5.0mm pupil diameter, root mean square values for total ocular higher-order aberrations (HOAs) were lower in groups A and B than in group C. Total ocular SA was lower in group A than in groups B and C. SA was also lower in group B than in group C. Coma and trefoil were similar between the groups.

CONCLUSION

Implantation of spherical aberration-free IOLs in eyes with different corneal SA results in similar visual performance at BCVA, contrast sensitivity and depth of focus.