Ocular Spherical Aberration Research Articles

Using adaptive optics to optimize the spherical aberration of eyes implanted with EDOF and enhanced monofocal intraocular lenses.

To assess the effect of change in ocular spherical aberration (SA) with adaptive optics on visual acuity (VA) at different defocus after implantation of extended depth-of-focus (EDOF) and enhanced monofocal intraocular lenses (IOLs). Narayana Nethralaya Eye Hospital, Bangalore, India. Prospective, longitudinal, observational. 80 eyes (40 patients) that had cataract surgery were included in the study. 40 eyes were implanted with Eyhance EDOF IOLs and the remaining with Vivity EDOF IOLs. Baseline ocular aberrations were measured with a visual adaptive optics aberrometer, then the optimal SA was determined by increasing it in steps of -0.01 μm up to -0.1 μm until the maximum improvement in near distance VA was observed for a given eye. Then the defocus curve for each eye was measured after modifying the ocular SA by magnitude equal to optimal SA. Most of the eyes accepted a negative induced SA of -0.05 μm (Eyhance group: 67.6%; Vivity group, 45.2%). In the Eyhance group (dominant eyes), VA improved at -2 diopters (D) ( P < .02) only and degraded at 0 D, +0.5 D, and +1 D defocus ( P < .05). In the Vivity group, the VA remained unchanged at all defocus ( P > .05). In the Eyhance group (nondominant eyes), VA improved at -3.5 D defocus only and degraded at +1.5 D and +2 D defocus ( P < .05). In the Vivity group, VA improved at -2.5 D defocus ( P < .05) only. A negative induced SA of -0.05 μm in implanted eyes was optimal for a slight improvement in distance-corrected near and intermediate VA without any significant decrease in baseline distance-corrected VA.

Effect of spherical aberration on visual acuity and depth of focus in pseudophakic eyes.

To assess the performance of 4 intraocular lenses (IOLs) in various spherical aberration (SA) conditions, using the VAO adaptive optics simulator. Cullen Eye Institute, Baylor College of Medicine, Houston, Texas. Prospective case series. Distance-corrected visual acuities at distance (CDVA), intermediate (DCIVA), and near (DCNVA) were measured in 42 dilated pseudophakic eyes at baseline and with ocular SA ranging from -0.4 to +0.4 μm in increments of 0.2 μm (6.0-mm pupil). 4 IOL types were assessed: monofocal IOLs with zero-SA, enhanced-monofocal, extended depth-of-focus (EDOF), and continuous range-of-vision. Compared with SA = 0 μm, significant changes (all P < .05) were: (1) zero-SA monofocal IOLs' DCNVA at high contrast improved by 0.13 logMAR with SA = -0.4 μm and worsened by 0.09 and 0.10 logMAR with SA = +0.2 and +0.4 μm, respectively. DCNVA at low contrast worsened by 0.09 logMAR with SA = +0.4 μm; and (2) with SA = -0.4 μm, the enhanced monofocal IOL lost 0.06 logMAR of CDVA at high contrast and gained 0.09 logMAR of DCNVA at low contrast. There were no significant changes from SA = 0 μm for EDOF and continuous range-of-vision IOLs. Zero-SA and EDOF IOLs were the most and least sensitive to SA modulation, respectively. In perfect optical systems where all the optical elements are aligned, induction of targeted amounts of negative SA improved the depth of focus of some IOL types. No benefit was found with positive SA.

Clinical and Aberrometric Outcomes of a New Implantable Collamer Lens for Myopia and Presbyopia Correction in Phakic Patients.

To assess the clinical and aberrometric outcomes of a new Implantable Collamer Lens (EVO Viva ICL; STAAR Surgical) to correct moderate to high myopia and presbyopia. The study included 80 eyes of 40 patients who had bilateral EVO Viva ICL implantation. Uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction, presbyopic add power, binocular through-focus visual acuity, total ocular spherical aberration (SA), coma aberration, and root mean square of ocular higher order aberrations (RMS HOAs) (i-Trace Aberrometer; Tracey Technologies) for a 4.5-mm pupil size were evaluated. The mean binocular postoperative UDVA and CDVA were 0.09 ± 0.19 and 0.02 ± 0.03 logMAR, respectively. The postoperative spherical equivalent was -0.61 ± 0.54 diopters (D). The presbyopic add power reduced from +1.31 ± 0.74 D preoperatively to +0.44 ± 0.58 D after surgery (P < .0001). The mean visual acuity was 0.1 logMAR or better (20/25 or better) across the vergence range from +0.50 to -1.50 D, better than 0.2 logMAR (20/32 or better) up to the vergence of -2.00 D, and remained better than 0.3 logMAR (20/40 or better) up to the vergence of -2.50 D. The total ocular aberrations induced by EVO Viva ICL were -0.34 ± 0.09 µm of SA, 0.24 ± 0.18 µm of coma, and 0.26 ± 0.12 µm of RMS HOAs. The outcomes support that the new ICL might be a good alternative for myopia and presbyopia correction in patients aged between 45 and 55 years. Further studies are needed to evaluate the threshold lens misalignment from which the patient´s visual quality would be affected. [J Refract Surg. 2023;39(9):589-596.].

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

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

Intraocular Lens Tilt and Decentration after Cataract Surgery with and without Primary Posterior Continuous Curvilinear Capsulorrhexis.

To evaluate intraocular lens (IOL) tilt and decentration and their effects on high-order aberrations (HOAs) after cataract surgery with and without primary posterior continuous curvilinear capsulorrhexis (PPCCC). Fujian Provincial Hospital, Fujian, China. Prospective, intraindividual, randomized, comparative clinical trial. This study enrolled 64 eyes of 32 patients with age-related cataract who underwent bilateral cataract surgery and IOL implantation. In randomized order, all patients had phacoemulsification cataract surgery with PPCCC in one eye (PPCCC group) and routine cataract surgery in the contralateral eye (NPCCC group). IOL decentration, tilt, HOAs, modulation transfer function, and point spread function were measured at 1 day, 1 week, 1 month, and 3 months after surgery using OPD-Scan III. 52 eyes of 26 patients were available for analysis. The mean overall decentration in NPCCC group was significantly higher than in PPCCC group at 3 months (0.302±0.157 mm vs 0.187±0.099 mm, P<0.001). Under 3-mm pupil, internal spherical aberration (SA) 1 day after surgery, and coma 1 week after surgery were lower in PPCCC group compared with NPCCC group (0.15±0.10 μm vs 0.30±0.21 μm, P<0.001, and 0.34±0.18 μm vs 0.47±0.31 μm, P=0.03, respectively). IOL decentration was significantly correlated with ocular and internal coma, ocular and internal SA, and internal HOAs at 5-mm pupil (R=0.083 and R=0.099, R=0.650 and R=0.613, R=0.418, respectively, all P<0.01). Less IOL decentration was observed in PPCCC group at 3 months after surgery, indicating that PPCCC may result in better IOL centrality.

Visual and refractive outcomes of new intraocular lens implantation after cataract surgery

To report the visual and refractive outcomes of new aspheric hydrophobic acrylic monofocal intraocular lens (IOL). Retrospective case series. This study included eyes of patients who underwent routine cataract surgery for uncomplicated age-related cataract with implantation of a Aktis SP (NS-60YG; Nidek Co. Ltd., Japan) IOL and attended regular follow ups at 1 week, 1 month, 3 months, and 12 months. At each post-operative visit, ophthalmological evaluation included measurement Uncorrected (UCVA) and Best corrected visual acuity (BCVA), contrast sensitivity, posterior capsular opacification (PCO), optical aberrations, analysis of point spread function (PSF) and modulation transfer function (MTF). The study included 2102 eyes of 1358 patients aged 45 to 75 years (mean age 62.6 years ± 5.6 SD). The mean preoperative BCVA was 0.56 ± 0.26 logMAR. At 1 year follow up, the mean postoperative UCVA and BCVA were 0.11 ± 0.09 and 0.02 ± 0.03 logMAR, respectively. At the end of 6 months, around 1487 (93%) eyes had BCVA of 20/20 and better than 20/30 in 100% of the eyes. Mild posterior capsule opacification (PCO) was observed in 56 patients, but none required Nd YAG laser capsulotomy. There was reduction in ocular spherical aberration and Higher order aberrations (HOAs) as compared to pre operative. This explains better contrast sensitivity obtained by MTF and PSF values. The study shows that the Aktis SP IOL is safe, effective, and stable lens that could be inserted through 2.2 mm incision with satisfactory visual and refractive outcomes, even in late post-operative period.

Comparative study of decentration, tilt and visual quality after implantation of aspherical intraocular lenses

Objective: To compare the difference of decentration and tilt among 4 kinds of aspherical intraocular lenses (IOLs), and to analyze their objective visual quality. Methods: Prospective non-randomized controlled clinical trial. Age-related cataract patients who planned to undergo phacoemulsification and IOL implantation in the Affiliated Hospital of North Sichuan Medical College from April to June in 2020 were divided into ZCB00 group, SN60WF group, A1-UV group, and AO group according to IOL types. Thirty right eyes and thirty left eyes were selected in each group. Before operation and at 1 day, 1 week and 1 month postoperatively, decentration and tilt values were measured by a new swept-source anterior-segment optical coherence tomography device (CASIA2), and wavefront aberrations, objective scatter index (OSI), modulation transfer function cut off frequency (MTF cut off) and Strehl ratio (SR) were also examined. Values of decentration, tilt and visual quality compared among 4 groups were took from the right eye. One-way analysis of variance was used for inter-group comparison, and repeated measurement one-way analysis of variance was used for intra-group comparison. Data between right eyes and left eyes from all the individuals were compared by independent sample t-test. Results: A total of 181 patients (240 eyes) were enrolled, and 169 patients (224 eyes) completed the follow-up (114 right eyes and 110 left eyes). There were 77 males and 92 females, with an age of (69±9) years. There was no significant difference in gender, age, axial length, decentration and tilt of crystalline lens and IOL power among 4 groups (all P>0.05). At 1 day, 1 week and 1 month postoperatively, there was significant difference in decentration value among 4 groups (F=7.11, 6.12, 4.66; all P<0.05). For further pairwise comparison, the decentration value of SN60WF group was higher than that of the other 3 groups at 1 day and 1 week postoperatively, and the decentration value of SN60WF group was (0.259±0.101) mm at 1 month postoperatively, which was higher than that of ZCB00 group (0.177±0.099) mm and AO group (0.163±0.122) mm, and the differences were statistically significant (using SNK-q test, both P<0.05). The IOL tilt value in the ZCB00 group, SN60WF group, A1-UV group, and AO group at 1 month postoperatively were (4.806±1.129)°, (5.080±1.309)°, (4.586±1.338)°, (5.112±1.406)°, respectively. No significant difference in tilt value among 4 groups was found at any time after surgery (all P>0.05). In each group, there was no significant difference in decentration and tilt value at different postoperative time points (all P>0.05). At 1 month postoperatively, there was no significant difference in decentration and tilt at horizontal and vertical directions respectively among 4 groups (all P>0.05), and in each group, there was no significant difference in decentration and tilt value between right eyes and left eyes (all P>0.05), and IOLs tended to tilt towards the inferonasal or inferotemporal direction in both eyes. With 4-mm and 6-mm pupil diameter, there was significant difference in internal (F=131.32, 85.17) and ocular (F=46.64, 47.55) spherical aberration among 4 groups (all P<0.01). For further pairwise comparison, the spherical aberration of AO group was higher than that of the other 3 groups, and the difference was statistically significant (using SNK-q test, all P<0.05). There was no significant difference in OSI, MTF cut off and SR among 4 groups (all P>0.05). Conclusions: The four types of IOLs show decentration and tilt in varying degrees after implantation in the capsular bag, but this difference do not lead to clinical significance. Human eyes have tolerance to mild decentration and tilt of aspheric IOLs, showing good visual quality.

Refractive and visual outcomes of two different aspheric monofocal intraocular lenses with differing tinting and spherical aberration values

Purpose: To compare refractive and visual outcomes of two diffractive monofocal intraocular lenses (IOLs) with different tinting and spherical aberration values. Study design: Retrospective case series. Methods: The right eye of consecutive patients who had undergone bilateral implantation of SZ-1 (NIDEK Co. Ltd., Gamagori, Japan) or ZCB00 (Johnson and Johnson Inc. New Brunswick, NJ, USA) IOLs was evaluated. Refractive outcomes, changes in visual acuity, ocular spherical aberration, and changes in photopic and mesopic contrast sensitivity were analyzed. Results: Thirty-three eyes received the SZ-1 IOL (SZ-1 group, while 29 eyes received the ZCB00 IOL (ZCB00 group). The mean preoperative manifest refraction spherical equivalent (MRSE) was −1.48 ± 4.74 D and −0.34 ± 1.50 in the SZ-1 group and ZCB00 group, respectively. At 3 months, the mean MRSE was −0.87 ± 1.08 D and −0.65 ± 0.76, respectively (p=0.25). At 3 months postoperatively, the mean best spectacle-corrected visual acuity was 0.14 ± 0.20 LogMAR and 0.11 ± 0.17 LogMAR, respectively (p=0.67). At the same time point, ocular spherical aberration was statistically significantly different (0.01 ± 0.23 μm vs. −0.51 ± 0.51 μm, respectively; p<0.0001). Postoperatively, the mean photopic and scotopic contrast sensitivity did not differ between the groups (p=0.57). Conclusion: Postoperative refractive outcomes and visual acuity following the implantation of these aspheric IOLs were similar. The different asphericity and yellow tinting of the SZ-1 IOL did not affect postoperative visual performance.

Long-term Outcomes After LASIK Using a Hybrid Bi-aspheric Micro-monovision Ablation Profile for Presbyopia Correction.

To evaluate visual outcomes 6 years after hybrid bi-aspheric multifocal central laser in situ keratomileusis for presbyopia correction (PresbyLASIK) treatments. Thirty-eight eyes of 19 patients consecutively treated with central PresbyLASIK were assessed. The mean age of the patients was 51 ± 3 years at the time of treatment with a mean spherical equivalent refraction of -0.57 ± 1.98 diopters (D) and mean astigmatism of 0.58 ± 0.57 D. Monocular corrected distance visual acuity (CDVA), corrected near visual acuity (CNVA), and distance-corrected near visual acuity (DCNVA), uncorrected distance visual acuity (UDVA), uncorrected intermediate visual acuity (UIVA), distance-corrected intermediate visual acuity (DCIVA), and uncorrected near visual acuity (UNVA) were assessed preoperatively and postoperatively for the dominant eye, non-dominant eye, and binocularly. Subjective quality of vision and near vision were assessed using the 10-item, Rasch-scaled, Quality of Vision (QoV) Questionnaire and Near Activity Visual Questionnaire (NAVQ), respectively. At 6 years postoperatively, mean binocular UDVA was 20/18 ± 4 and mean binocular UNVA and UIVA were 0.11 ± 0.13 and -0.08 ± 0.08 logRAD, respectively. Spherical equivalent showed a slow hyperopic drift of +0.10 D per year with refractive astigmatism stable from 6 weeks postoperatively. Defocus curves showed an improvement of 0.4 Snellen lines at best focus from 1 to 6 years of follow-up, reaching preoperative levels. Compared to the preoperative status, the corneal and ocular spherical aberrations (at a 6-mm diameter) decreased and were stable from 3 months of follow-up. Questionnaires revealed a postoperative unaided QoV score comparable to preoperative scores and with an improved postoperative unaided NAVQ score compared to preoperative scores with best correction. Presbyopic treatment using a hybrid bi-aspheric micro-monovision ablation profile is safe and efficacious even after 6 years postoperatively. The postoperative outcomes indicate improvements in binocular vision at far, intermediate, and near distances. An 8% re-treatment rate should be considered to increase satisfaction levels, including a 3% reversal rate. [J Refract Surg. 2020;36(2):89-96.].

Effect of Orthokeratology Lens on Contrast Sensitivity Function and High-Order Aberrations in Children and Adults.

Overnight orthokeratology (OOK) lenses are used to temporarily decrease myopic refractive error and improve uncorrected vision. Overnight orthokeratology lenses significantly increase ocular and corneal high-order aberrations (HOAs) and compromise contrast sensitivity function (CSF) to a degree correlated with myopic correction achieved. In Taiwan, OOK lenses are mainly used in children for myopia control. However, information regarding its effects in this population remains limited. This study discusses the change in HOAs and CSF after 28 nights of OOK lens use in children compared with that in adults. In total, 46 children (9-18 years) and 26 adults (>18 years) who visited Ophthalmology Department of Mackay Memorial Hospital from October to December 2013 were enrolled. Contrast sensitivity and ocular/corneal total high-order, coma, and spherical aberrations (SA) were tested before OOK treatment. After 28 days of overnight use, CSF and topography were reexamined, and data were collected and analyzed using t test and Pearson correlation coefficients. In total, 23 eyes of 23 children and 14 eyes of 14 adults were evaluated. The treatment resulted in a significant increase in ocular total HOA, coma, and SA in both groups. However, CSF declined more in adults than children. Our study revealed that OOK lenses decrease CSF to a greater extent in adults than that in children despite no significant differences in the change of ocular HOAs between both subject groups. We proposed children may have better neural adaptation to compensate for optical aberrations induced by OOK lens use.

Correlation and predictability of ocular aberrations and the visual outcome after quadrifocal intraocular lens implantation: a retrospective longitudinal study

BackgroundTo evaluate the correlating and predicting factors of visual outcome after implantation of newly developed diffractive quadrifocal intraocular lens (IOL).MethodsA retrospective longitudinal study was conducted. Patients who underwent diffractive quadrifocal IOL implantation with a follow-up period longer than six months and records of wavefront aberrometer within one week perioperatively were enrolled. Accordingly, a total of 73 eyes from 73 patients were included. The postoperative distance and near visual acuity, ocular aberrations and postoperative symptoms were collected. The correlation and predictability between ocular aberrations and the postoperative visual outcome were evaluated.ResultsThe corrected distance visual acuity (CDVA) one month postoperatively was significantly better than the preoperative status, and insignificant improvement was found six months postoperatively. Preoperative Tracey refraction spherical equivalent (TRSE), angle alpha, and spherical aberration (SA) were significantly correlated with postoperative CDVA and near corrected visual acuity (NCVA). For postoperative ocular aberrations, TRSE, angle alpha, and SA were significantly correlated with CDVA six months postoperatively and NCVA, while the trefoil, internal higher order aberration (HOA) and total HOA were associated with NCVA. Preoperative angle alpha could predict all postoperative visual performances, while postoperative TRSE and angle alpha could predict the CDVA six months postoperatively and NCVA. A large angle alpha is associated with visual disturbance and dissatisfaction.ConclusionThe angle alpha preoperatively and postoperatively was correlated with the postoperative vision and could predict visual outcome in patients who had diffractive quadrifocal IOL implanted. Furthermore, the majority of ocular aberrations were also associated with certain postoperative vision.

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

BackgroundTo compare the postoperative optical quality in eyes with customized selection and random selection of aspheric intraocular lens (IOL) implantation.MethodsA 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.ResultsEighty-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).ConclusionsAlthough 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 registrationRetrospectively registered on 07/06/2019. Registration number: ChiCTR1900024356.

Evaluation of Visual Quality in Pseudophakic Eyes with Different Ocular Spherical Aberrations

ABSTRACT Purpose To evaluate the effects of different residual total ocular spherical aberration (SA) on objective and subjective visual quality in pseudophakic eyes. Methods This prospective consecutive study comprised 171 patients with age-related cataract and undergone unilateral uneventful phacoemulsification. All participants were divided into four groups based on residual ocular SA at 6 mm pupil: negative SA (≤−0.10 μm, group A), neutral SA (0.00 ± 0.05 μm, group B), slightly positive SA (0.10 ± 0.05 μm, group C), and more positive SA (0.20 μm, group D), respectively. Subjective visual acuity and contrast sensitivity, and objective optical quality and ocular aberrations were analyzed 3 months postoperatively. Results There was no significant difference in baseline measurements across all groups. Postoperatively, no statistically significant differences were found in visual acuity between groups (P > .05), while differences reached statistical significance in mesopic contrast sensitivity at 12 and 18 cpd (P < .01). There were significant differences in ocular SA and higher-order aberrations at 6 mm pupil, as well as in optical quality parameters (P < .05). Group C showed a minimum value of objective scatter index (1.17 ± 0.55) but maximum values of modulation transfer function cutoff (31.94 ± 9.18) and optical quality value OV 100% (1.07 ± 0.31), indicating lower intraocular scattering and superior optical quality. Conclusions This comprehensive evaluation is conducive to deepening the understanding of visual and optical performance of pseudophakic eye. A modest amount of positive ocular SA seemed to be a more preferable option for enhancing visual quality after aspheric ntraocular lense (IOL) implantation.

Comprehensive Evaluation of Retinal Image Quality in Comparing Different Aspheric to Spherical Intraocular Lens Implants

ABSTRACTPurpose: To compare the visual and optical quality of eyes implanted with three aspheric versus two spherical intraocular lenses (IOL) after cataract surgery.Methods: This prospective comparative study included 349 eyes of 349 patients with age-related cataract and undergone uneventful phacoemulsification. Implanted posterior monofocal IOLs have an aspheric optic (Tecnis ZCB00 [Johnson & Johnson Vision], Acrysof IQ SN60WF [Alcon], Akreos AO [Bausch & Lomb]) or a spherical optic (Akreos [Bausch & Lomb], Sensar AR40e [Johnson & Johnson Vision]). Postoperatively, objective optical quality parameters were performed using an Optical Quality Analysis System II (Visiometrics), and wave-front aberrations were assessed using a KR-1W aberrometer (Topcon). Meanwhile, subjective visual acuity was performed using a logarithm of the minimum angle of resolution chart at 3 months after cataract surgery.Results: Statistical significant differences (P < .05) across all groups were found regarding intraocular and total ocular spherical aberration (SA) at 4.0 mm and 6.0 mm pupil diameter and total high-order aberration (tHOA) at 6.0 mm pupil diameter. Furthermore, differences among the evaluated groups were observed regarding several objective parameters such as objective scatter index (OSI), modulation transfer function cutoff (MTF cutoff), Strehl ratio (SR) at two dimensions and contrast visual acuity (OV) at three contrast levels.Conclusions: The present results reflect the optical characteristics of IOL in vivo. The scattering light and high-order aberration may be the main reasons for the degradation of retinal imaging quality in comparing different aspheric to spherical IOL implants.

Optical behavior of the eye implanted with extreme intraocular lens powers

To evaluate the induced ocular aberrations after cataract surgery with extreme low- powered and high-powered spherical monofocal intraocular lenses (IOLs) using a new pyramidal wavefront sensor aberrometer. Vissum Instituto Oftalmológico, Alicante, Spain. Prospective observational comparative study. This study included patients who had cataract surgery with implantation of a spherical monofocal IOL. The patients were divided into three groups according to the IOL power. Group 1: +20 diopters (D) to +23 D; Group 2: less than +10 D; and Group 3: +29 D or more. Assessment after 3months included: uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction, contrast sensitivity function test (Ginsburg), corneal aberrometry, and total ocular aberrometry with a pyramidal wavefront sensor aberrometer (Osiris) for 4.0mm, 4.5mm, and 5.0mm pupil diameters. The study comprised 88 eyes of 56 patients. There were no differences between all groups in terms of refractive error, corneal aberrometry, or total ocular higher-order aberrations at any analyzed pupil diameter. The ocular spherical aberration (SA) was not significantly different between groups with a 4.0mm pupil. The SA was significantly lower in Group 2 when compared with Group 1 and Group 3 for both 4.5mm(P=.01 and P=.001, respectively) and 5.0mm(P=.002 and P=.002, respectively). There was no significant difference in SA between Group 1 (+20 D to 23 D) and Group 3 (≥+29 D) at any analyzed pupil diameter. Higher SA did not correlate to lower contrast sensitivity. Despite the theoretical evidence, only a negligible amount of clinically insignificant aberrations were induced by high-powered positive IOLs. Low-powered IOLs did not induce significant levels of SAs.

Effects of decentration and tilt on the optical performance of 6 aspheric intraocular lens designs in a model eye

To compare the effect of decentration and tilt on the optical performance of 6 aspheric intraocular lens (IOL) designs in a model eye. Department of Ophthalmology, Graduate School of Medicine, Dokkyo Medical University, Tochigi, Japan. Experimental study. In theoretical simulations, the amount of spherical aberration in the IOL was varied to produce residual ocular spherical aberration (range -0.15 to 0.30μm) at a 6.0mm entrance pupil. Wavefront aberration analyses were performed with the ZEMAX optical design program (version August 20, 2014) to obtain the ocular root-mean-square values of astigmatism, coma, trefoil, and higher-order aberrations (HOAs) when the IOL was centered on the insertion position and misaligned at a 4.0mm entrance pupil. The retinal visual images were calculated using the same conditions. Six 20.0 diopter (D) aspheric IOLs and one 20.0 D spherical IOL were used for the experimental studies. Each IOL was inserted in the model eye. The actual alignments were measured using a Scheimpflug camera (EAS-1000). The wavefront aberrations and visual images were gauged using a wavefront analyzer (KR-1W) at several IOL alignments. Intraocular lens decentration and tilt increased wavefront aberrations and degraded optical performance. Astigmatism, coma, and HOAs generated by misaligned IOLs were related to the amount of spherical aberration correction of the IOLs. The extent of spherical aberration remained unchanged by the amount of misalignment. Experimental model eye results showed trends similar to theoretical results. The spherical aberration correction amount in the aspheric IOL design was critical for the astigmatism, coma, and HOAs generated by the IOL misalignment. Additional spherical aberration corrections led to a more sensitive optical performance degradation resulting from IOL misalignment.

Multifocal contact lenses: towards customisation?

Firstly, to determine if eyes with spherical aberration (SA) that deviates significantly from the average level underperform when fitted with a simultaneous-imaging contact lens (CL) with a power profile calculated for an 'average eye'. Secondly, to determine if CL customisation can improve image quality in these eyes after fitting with a bifocal CL. A statistical model of the wavefront aberration function of normal eyes was used to generate a vector of Zernike fourth-order SA coefficients from 100 synthetic eyes. Four bifocal power profiles were modelled: centre-near (CN) or centre-distance (CD), and two-zone or four-zone. All designs had 0.1-mm-wide transition zones. Different levels of distance and add powers were modelled, using well-established computational wave-optics methods. Zone widths were optimised to obtain maximal multifocal efficiency (MFE), a metric based on the visual Strehl that synthesises the through-focus curve in one number. The MFE was calculated for each synthetic eye coupled with each bifocal power profile. For an 'average eye', the mean MFE values were 0.33 vs 0.25 and 0.32 vs 0.29, for CN vs CD and two vs four zone designs, respectively. When the four power profiles were assessed in eyes with non-average levels of ocular SA, the MFE decreased with higher levels of SA (eye and CL combined) for all designs. Some of this reduction in MFE could be prevented by adjusting the nominal distance and add power of the bifocal profiles to compensate for the increased or decreased level of combined SA. The four-zone CN profile showed better tolerance for different levels of ocular SA than the two-zone designs, but this was not true for the four-zone CD design. Eyes with SA levels differing significantly from the average level underperform when fitted with simultaneous-imaging CLs with power profiles calculated for average eyes. Our findings suggest that visual performance at distance and near when wearing bifocal CLs can be improved by using a semi-customised approach.

Patient-specific determination of change in ocular spherical aberration to improve near and intermediate visual acuity of presbyopic eyes.

The purpose was to determine the optimum negative spherical aberration induction required to improve near and intermediate visual acuity (VA) of presbyopic eyes. A total of 174 normal and diabetic (no retinopathy) presbyopic eyes (age ≥ 40 years) were measured with visual adaptive optics simulator (Voptica, Spain). First, baseline uncorrected VA and aberrations were measured. VA at 40 cm (near), 80 cm (intermediate) and distance was measured. Then, a negative spherical aberration (SA) was added to baseline ocular SA, and VA at all targets was reassessed after correction of distance refractive error. Clinically, baseline SA and root mean square of higher order aberrations were similar between the normal and diabetic presbyopic eyes. Baseline VA of the diabetic eyes at near and intermediate was better than the same of normal eyes (P = 0.001). After SA change, VA at near and intermediate of both normal and diabetic presbyopic eyes improved. However, fewer diabetic eyes needed higher SA change than normal eyes (P = 0.03). The corresponding trends with change in VA at near and intermediate were also similar between the normal and diabetic eyes. Patient-specific modulation of ocular SA to improve near and intermediate VA in a large cohort of eyes was successful in improving VA, sometimes even distance VA.

First results with a new intraocular lens design for the individual correction of spherical aberration

To assess the feasibility of individual compensation of corneal spherical aberration with a custom intraocular lens (IOL). Department of Ophthalmology, Rudolf Virchow Klinikum Glauchau, Glauchau, Germany. Prospective case series. Cataract patients were randomized to receive an individual aberration-correcting IOL (Invidua-aA; Group A) or a standard aspheric aberration-free IOL of otherwise identical design (Aspira-aA; Group B). In Group A, the IOL was designed according to preoperative calculation of the corneal spherical aberration Z(4,0). The aim was to achieve an overall postoperative ocular spherical aberration close to zero. Four weeks and 3months postoperatively, the refraction, visual acuity (far, intermediate, and near distance), photopic and mesopic contrast sensitivities (with and without glare), defocus curve, corneal and ocular spherical aberration, and pupil size were measured. Group A, 57 eyes of 42 patients and Group B, 29 eyes of 27 patients. Preoperatively, there was no difference in corneal spherical aberration between groups (P>.05). Three months postoperatively, residual ocular spherical aberration Z(4,0) was significantly lower in Group A (P<.001). Photopic and mesopic contrast sensitivities (with and without glare) were significantly higher in Group A at most spatial frequencies. Monocular defocus curve and distance, intermediate, and near visual acuity outcomes did not differ significantly between groups. Implantation of a custom monofocal aspheric IOL effectively reduced overall ocular spherical aberration. Clinical outcomes indicate that IOLs with an individual spherical aberration correction improve functional vision, especially contrast sensitivity, compared with standard aberration-free IOLs.

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

BackgroundTo assess the precision and agreement of measurements of higher order aberrations (HOAs) obtained with a ray tracing aberrometer (iTrace) and a Hartmann-Shack aberrometer (Topcon KR-1 W).MethodsProspective evaluation of the diagnostic test. Data from the right eyes of 92 normal subjects obtained using the two devices were included in this study. Two observers performed 3 consecutive scans to determine the intraobserver repeatability and interobserver reproducibility. About one week later, one observer performed an additional 3 consecutive scans to obtain the intersession reproducibility. The within-subject standard deviation (Sw), test-retest repeatability (TRT) and intraclass correlation coefficient (ICC) were used to assess the precision, while Bland-Altman plots were performed to assess the agreement.ResultsFor intraobserver repeatability of the ocular, corneal and internal HOAs, Topcon KR-1 W showed a 2.77Sw of 0.079 μm or less and ICCs of 0.761 or more; and iTrace showed a 2.77Sw of 0.105 μm or less and ICCs of 0.805 or more. The ICCs of the internal HOAs of interobserver reproducibility were less than 0.75 except for spherical aberration (SA) (0.862), and interobserver reproducibility of the counterpart showed similar but lower results. For the ocular, corneal and internal HOA measurements, statistically significant differences existed between the Topcon KR-1 W and iTrace (all P < 0.05). No significant differences were observed in the ocular SA and internal coma.ConclusionsThe ray tracing and Hartmann-Shack method aberrometers provided excellent repeatability but less reliable reproducibility in the measurement of HOAs (except for SA). The two aberrometers should not be interchangeable in clinical application because of the significant differences in HOA measurements between them.