Aspheric Intraocular Lens Research Articles

Profile of a new extended range-of-vision IOL: a laboratory study

PurposeTo evaluate the surface profile of a new-generation extended range-of-vision intraocular lens (IOL) and to compare it with that obtained for a monofocal IOL based on the same platform.MethodsProspective, experimental, laboratory study comparing the surface profile of the DFT015 (AcrySof IQ Vivity; Alcon Laboratories, Inc.), a new-generation presbyopia-correcting IOL, with the profile of the SN60WF (AcrySof IQ; Alcon Laboratories, Inc.), an aspheric monofocal IOL based on the same platform. Raw profiles were obtained using contact profilometry. The best-fit form was then subtracted from each raw profile to highlight potential differences.ResultsNo significant differences were appreciated in raw profiles. On the contrary, after form removal, the new extended range-of-vision IOL showed a peculiar profile characterized by the presence of two altitudinal symmetrical changes in the order of 1 µm, localized in the central portion of the optic.ConclusionsThe new-generation extended range-of-vision IOL evaluated showed a smooth change of its surface compared to the same platform monofocal IOL. The altitudinal changes blended in the central design of the new presbyopia-correcting IOL, although micrometric, might play a crucial role in creating a continuous focal range while minimizing visual disturbances.

Long-Term Clinically Significant Posterior Capsular Opacification Development Pattern in Eyes Implanted with an Aspheric Monofocal Intraocular Lens with a Square Optic Edge.

Purpose To analyse the posterior capsular opacification (PCO) development pattern in the long term in eyes implanted with a monofocal intraocular lens (IOL) with a square edge all around the optic. Methods Longitudinal retrospective study is data analyzed from a total of 7059 eyes from 4764 patients (mean age: 75.8 years) undergoing cataract surgery with implantation of an aspheric monofocal IOL (Bi-Flex HL 677AB/677P, Medicontur, Budapest, Hungary). These data were retrospectively collected using the electronic medical record of the hospitals involved. Nd : YAG capsulotomy rates were calculated per year during a follow-up of more than 10 years. The Kaplan–Meier analysis was used to establish the transparent capsule survival rate. Results The Nd : YAG capsulotomy rate increased from 1.1% at 1 year postoperatively to 17.2% at 5 years after surgery. No significant differences were found between eyes with and without capsulotomy in terms of age (p = 0.202), gender (p = 0.061), type of anaesthesia used (p = 0.128), and presence of conditions such as hard cataract (p = 0.111) or pseudoexfoliation (p = 0.137). IOL power was significantly lower in those eyes of patients requiring Nd : YAG capsulotomy during the follow-up (p < 0.001). Significantly more eyes implanted with the preloaded model of the IOL required capsulotomy (p < 0.001). Mean survival time and rate were 9.38 years and 85.9%, respectively. Conclusions Most eyes undergoing cataract with implantation of the Bi-Flex IOL do not develop a clinically significant PCO requiring Nd : YAG capsulotomy in the long term. IOL material and design may be the main factors accounting for this finding.

Effect of misalignment at different orientations associated with angle κ on optical performance of aspheric intraocular lenses with different surface designs.

Intraocular lens (IOL) misalignment and angle κ have had significant negative impact on post-operative quality of vision. ZEMAX software has been used to imitate the optical performance of pseudophakic eyes with different IOL surface designs at different orientations of IOL misalignment (decentration of 0.4 mm and tilt of 7°, and with the existence of 0.5 mm angle κ). We found that an aspheric balanced curve optic surface maintained better optical performance via inducing less coma aberration. Coma aberration played an unexpectedly important role in the optical performance. With angle κ, the impact of IOL misalignment on visual quality was associated with the orientation of decentration and tilt, indicating that the coma compensation also took effect in pseudophakic eyes. Due to the high incidence of post-operative IOL misalignment, our results provide evidence of the importance of considering personalized angle κ before cataract surgery for patients.

Contrast Sensitivity Test After Phacoemulsification with Implantation of Hydrophobic Aspheric Monofocal Intraocular Lens (IOL) at Family Medical Center Hospital Sentul

In Indonesia, the prevalence of cataract is 80 %. The main purpose of phacoemulsification with theimplantation of intraocular lens (IOL) is to improve visual acuity on cataract patient. The outcome ofcataract surgery should be evaluated based on visual acuity and quality of vision. Contrast sensitivityexamination can provide important information about the visual capabilities of individuals. The aim of thisresearch is to find out the contrast sensitivity value on cataract patients after phacoemulsification with theimplantation of hydrophobic aspheric monofocal IOL at FMC Hospital, Sentul on December 2018 untilJanuary 2019. This research used cross sectional descriptive design. The contrast sensitivity test isconducted on subject that fulfill the inclusive and exclusive criteria. This test is conducted using Vistech6500. The mean value of contrast sensitivity of 50 eyes at 1.5 cpd was 184.11, at 3 cpd was 235.5, at 6 cpdwas 207.360, at 12 cpd was 119.830, and at 18 cpd was 52.914. The result, the mean contrast sensitivity of50 eyes at the 1.5 and 3 cpd is higher compared to maximum value of Vistech 6500. However at 6, 12 and 18cpd the mean contras sensitivity depleted compared to maximum value of Vistech 6500. The result of meancontrast sensitivity based on age was the middle-aged (45-59 years) had a better contrast sensitivitycompare than young old (60-74 years) and very old category (75-90 years).

Multicountry clinical outcomes of a new nondiffractive presbyopia-correcting IOL.

To evaluate the effectiveness and safety of a new presbyopia-correcting intraocular lens (IOL) with a nondiffractive design, DFT015, compared with an aspheric monofocal IOL, SN60WF. 19 investigational sites in 4 countries: Australia, Canada, Spain, and the United Kingdom. Prospective, randomized, parallel-group, controlled, assessor- and patient-masked clinical study. Participants aged ≥22 years with bilateral cataracts were randomized to DFT015 or SN60WF in a 5:4 ratio and masked until final postoperative follow-up at month 6. The primary effectiveness objective was superiority of DFT015 over SN60WF in mean monocular photopic distance-corrected intermediate visual acuity (DCIVA) at month 3. Secondary effectiveness objectives included noninferiority of DFT015 to SN60WF in mean monocular photopic corrected distance visual acuity (CDVA) and superiority in the mean monocular photopic distance-corrected near visual acuity (DCNVA) at month 3. Visual disturbances were assessed at month 6. 282 patients were randomized to DFT015 (n = 159) or SN60WF (n = 123). All effectiveness objectives were achieved at month 3 in first eyes. For monocular photopic results in first eyes, DFT015 demonstrated superior mean DCIVA (least squares means of -0.139 logMAR in favor of DFT015, P < .001), noninferior mean CDVA (97.5% upper confidence limit [UCL] of the difference was <0.1 logMAR) and superior mean DCNVA (95% UCL of the difference was <0.0 logMAR) compared with SN60WF at month 6. DFT015 exhibited a similar visual disturbance profile to that of SN60WF. DFT015 provided superior intermediate and near vision and a similar visual disturbance profile compared with an aspheric monofocal IOL.

Stability of Various Types of Aspheric Intraocular Lenses After Implantation: A One-Year Retrospective Study.

ObjectiveThe aim of the present study was to evaluate the stability of four different types of aspheric intraocular lenses (IOLs) after implantation.MethodsThis retrospective study included 124 eyes implanted with four different types of aspheric IOLs including a one-piece four-loop fixed hydrophilic acrylic IOL, a one-piece flat fixed acrylic IOL, a one-piece two-loop fixed acrylic IOL, and a three-piece two-loop fixed silicone IOL. IOL decentration, tilt, and ocular coma‐like aberration (coma) at one-week, one-month, three-month, and one-year time points were evaluated postoperatively.ResultsIOL decentration, tilt, and coma in the AO, 36A, IQ, and KS-AiN implantation groups were statistically significantly different one week and one year postoperatively (p < 0.01). There were significant differences between each of the pairs of groups (p < 0.01), except for coma between the AO and 36A implantation groups one week postoperatively (p > 0.05). When comparing the different time points (ie, one week, one month, three months, and one year postoperatively), IOL decentration, tilt, and coma were significantly different in each group (p < 0.05). IOL decentration, tilt, and coma in each group increased over the period from one week to one year postoperatively. A positive linear correlation was observed between IOL decentration or tilt and coma one year postoperatively (p < 0.01).ConclusionOne-piece multi-point fixed acrylic IOLs demonstrate better stability when compared with three-piece two-point fixed silicone IOLs. IOL decentration, tilt, and coma increase gradually over time. Ocular coma‐like aberrations are influenced by the stability of IOLs.

Individual design of aberration-free intraocular lenses.

An analytical tool capable of easily calculating a new aspheric intraocular lens (IOL) (shape factor, aspherization) chosen to be designed as "aberration free" in terms of spherical aberration and/or coma is reported. In terms of retinal image quality, the theoretical performances given by the new proposed IOLs compare well with commercial IOLs.

Does Every Calculation Formula Fit for All Types of Intraocular Lenses? Optimization of Constants for Tecnis ZA9003 and ZCB00 Is Necessary.

Background and Objectives: To evaluate the performance of intraocular lenses (IOLs) using power calculation formulas on different types of IOL. Materials and Methods: 120 eyes and four IOL types (BioLine Yellow Accurate Aspheric IOL (i-Medical), TECNIS ZCB00, TECNIS ZA9003 (Johnson & Johnson) (3-piece IOL) and Softec HD (Lenstec)) were analyzed. The performance of Haigis, Barret Universal II and SKR-II formulas were compared between IOL types. The mean prediction error (ME) and mean absolute prediction error (MAE) were analyzed. Results: The overall percentage of eyes predicted within ±0.25 diopters (D) was 40.8% for Barret; 39.2% Haigis and 31.7% for SRK-II. Barret and Haigis had a significantly lower MAE than SRK-II (p < 0.05). The results differed among IOL types. The largest portion of eyes predicted within ±0.25 D was with the Barret formula in ZCB00 (33.3%) and ZA9003 (43.3%). Haigis was the most accurate in Softec HD (50%) and SRK-II in Biolline Yellow IOL (50%). ZCB00 showed a clinically significant hypermetropic ME compared to other IOLs. Conclusions: In general, Barret formulas had the best performance as a universal formula. However, the formula should be chosen according to the type of IOL in order to obtain the best results. Constant optimizations are necessary for the Tecnis IOL ZCB00 and ZA9003, as all of the analyzed formulas achieved a clinically significant poor performance in this type of IOL. ZCB00 also showed a hypermetropic shift in ME in all the formulas.

Efficacy comparison between toric intraocular lens and aspheric intraocular lens plus steep-axis incision in cataract patients with low corneal astigmatism.

The present study aimed to evaluate and compare the efficacy of toric intraocular lens (IOL) implantation and aspheric IOL implantation with steep-axis incision for correcting mild to moderate corneal astigmatism in cataract patients. A prospective, single-center, open label, randomized, two-arm study was designed. Cataract patients with corneal astigmatism of 1.0-2.0D were enrolled and divided into test and control groups. The test group had the AcrySof® IQ Toric IOL implanted and the control group had the AcrySof® IQ IOL implanted with a steep-axis corneal incision. All patients underwent examinations of uncorrected distance visual acuity (UCDVA), corrected distance visual acuity (CDVA), subjective refraction, and corneal astigmatism before surgery and at the 1-day, 1-month, and 3-month follow-ups. Vector astigmatism analysis was evaluated using the Alpins method. We enrolled 26 eyes of 20 patients in the study, with 13 eyes in each group. The test group had better vision than the control group at the 3-month follow-up and had more cases with a UCDVA of 20/20 (10/13 vs. 4/13). The surgically induced astigmatism (SIA) vector of the test group was higher than that of the control group (1.22±0.64 vs. 0.84±0.45). The correction index of the test group was closer to 1 compared to that of the control group (0.7 vs. 0.46). Approximately 85% of patients in the test group had an angle of error within -15° to 15°. However, only 23% of patients in the control group were within that range. Though steep-axis corneal incision was cost-saving and easy-to perform, its astigmatismcorrecting efficacy was not as good as the Toric IOL implantation for cataract patients with low to moderate corneal astigmatism.

Comparison of spherical and aspherical intraocular lenses with decentration and tilt error using a physical model of human contrast vision and an image quality metric

PurposeIn this study, two intraocular lenses (spherical IOL SA60AT and aspherical IOL SN60WF) are examined in an eye model under conditions of misalignment (defocus, decentration and tilt). The lenses are rated using the contrast sensitivity function (CSF) based on Barten's physical model. The square root integral (SQRI) method is used as a quality criterion comparable to the subjective image quality assessment of the human eye. MethodsThe IOLs to be tested are decentered from 0 to 1mm and tilted from −5 to +5 degrees in the Navarro eye model (optimized for far-point 6m and pupil aperture 3mm). The defocus of the IOLs is ±0.1mm at the anterior chamber depth (ACD). The optical modulation transfer function (MTF) is simulated with a ray tracing program. The SQRI is calculated using this MTF and the Barten CSF model (for in-focus at aperture 3 and 4.5mm and for defocus at 3mm). ResultsWith increasing decentration, the spherical IOL shows a significantly smaller loss of quality for both apertures compared to the aspherical lens. With an aperture of 4.5mm, the image quality of the aspherical IOL is better for small decentration and tilt. The loss of quality of the spherical IOL increases with increasing tilt in both directions. In contrast, the image quality of the aspherical IOL is reduced under decentration for certain tilt values. For ACD−0.1mm, both IOLs behave similarly to the in-focus situation. For ACD+0.1mm, the influence of tilt without decentration is small for both IOLs. With increasing decentration, the quality loss of the aspherical IOL is similar to that in-focus and greater than that of the spherical lens. ConclusionIn general, under the same conditions the spherical SA60AT displays a lower tolerance in loss of quality of subjective vision with lens alignment errors, in comparison to the aspherical SN60WF, limited by certain combinations of decentration and tilt according to this study. This study shows a way to evaluate IOLs based on the subjective visual performance of the eye.

Rotational Stability of a New Hydrophobic Acrylic IOL With Modified C-loop Haptics.

To assess rotational stability, axial stability, decentration, and tilt of the Rayner RAO800C single-piece hydrophobic acrylic intraocular lens (IOL) (Rayner Intraocular Lenses Ltd) from end of surgery to 4 to 7 months postoperatively. Surgeries were performed at the Department of Ophthalmology at the Medical University of Vienna. A total of 130 eyes of 68 patients received an aspheric hydrophobic Rayner RAO0800C IOL. IOLs were randomly implanted to the 0 ± 10, 45 ± 10, 90 ± 10, or 135 ± 10 degree axis. Baseline measurement was performed with the patient still supine on the operating table. Axis alignment after 1 hour, 1 week, 1 month, and 4 months was evaluated by retroillumination pictures. Postoperative IOL decentration, tilt, and aqueous depth at 4 months were assessed using an anterior segment swept-source optical coherence tomography. Absolute median IOL rotation from end of surgery to 4 months was 2.4 degrees (range: 0.0 to 85.0 degrees). Median IOL rotation from end of surgery to 1 hour, 1 hour to 1 week, 1 week to 1 month, and 1 month to 4 months was 1.6 (range: 0.0 to 86.2), 1.1 (range: 0.0 to 28.8), 0.6 (range: 0.0 to 5.2), and 0.7 (range: 0.0 to 2.6) degrees. Respective proportions of IOLs rotating more than 5, 10, and 20 degrees from end of surgery to 4 months were 23.9%, 11.0%, and 6.4%. Horizontal and vertical decentration at 4 months was -0.09 ± 0.14 and 0.09 ± 0.14 mm, respectively. Horizontal and vertical tilt at 4 months was -4.78 ± 1.36 and -1.58 ± 1.10 degrees, respectively. A posterior axial shift of 0.052 ± 0.055 mm was observed from 1 week to 4 months. Although median IOL rotation appeared to be low, a significant proportion of IOLs rotated postoperatively. Decentration and tilt values were generally low. A minimal posterior optic shift was observed after 1 week. [J Refract Surg. 2021;37(2):112-118.].

Project hyperopic power prediction: accuracy of 13 different concepts for intraocular lens calculation in short eyes

PurposeTo evaluate the accuracy of intraocular lens (IOL) power calculation in a patient cohort with short axial eye length to assess the performance of IOL power calculation schemes in strong...

Safety and efficacy of A1-UV aspheric intraocular lens implantation over the postoperative 5 years

Objective: To evaluate the clinical safety and efficacy of A1-UV aspheric intraocular lens (IOL) implantation over the postoperative 5 years. Methods: Prospective cohort study. The subjects came from a finished multicenter, randomized and controlled clinical trial with a follow-up period of 1 year from April to November 2012. The clinical research centers were Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Peking University Third Hospital, Tianjin Medical University Eye Hospital, and Daping Hospital of Army Medical University. Cataract patients in the experimental group were implanted with A1-UV type IOL, while cataract patients in the control group were implanted with SN60WF type IOL, and monocular patients were enrolled. From April to May 2018, patients enrolled in the previous study were recalled for follow-up and continued observation. The visual acuity, spherical equivalent, postoperative complications, non-contact intraocular pressure and subjective evaluation results were statistically analyzed preoperatively, at 1 to 2 days, 1 week, 1 month, 3 months, 6 months, 1 year and 5 years after operation. The main statistical methods included Mann Whitney U test, Wilcoxon signed rank test, independent sample t test, chi square test and Fisher exact test. Results: A total of 42 subjects (22 in the experimental group and 20 in the control group) completed 5-year continuous observation. Among the 42 subjects, 28 were female and 14 were male. The age was (70±9) years, and the time from surgery to recall was (5.77±0.19) years. The age, gender distribution, left/right eye distribution, axial length, IOL power and nucleus hardness classification data of the experimental group and the control group were balanced and comparable (all P>0.05). At different visiting time points, there was no significant difference in the best corrected distance visual acuity (BCDVA), best corrected near visual acuity (BCNVA), uncorrected distance visual acuity (UCDVA) and uncorrected near visual acuity (UCNVA) between the groups (all P>0.05). At 5 years after operation, the UCDVA, BCDVA and BCNVA of the two groups were significantly improved compared with the baseline [all P<0.01; UCDVA was improved from 0.75 (0.30 to 1.30) to 0.10 (-0.10 to 0.70) in the experimental group and from 0.75 (0.30 to 1.60) to 0.20 (-0.10 to 0.80) in the control group; BCDVA was from 0.60 (0.10 to 1.00) to 0.00 (-0.10 to 0.54) in the experimental group and from 0.60 (0.10 to 1.60) to 0.10 (-0.10 to 0.50) in the control group; BCNVA was from 0.55 (0.00 to 1.10) to 0.10 (-0.10 to 0.60) in the experimental group and from 0.55 (0.10 to 1.60) to 0.10 (-0.20 to 0.60) in the control group], but there was no significant change in the UCNVA (both P>0.05). There were no significant differences in the spherical equivalent, intraocular pressure, subjective evaluation of visual adverse symptoms, distance vision spectacle independence and comprehensive evaluation of satisfaction between the groups (all P>0.05). In the experimental group, one eye (4.5%) had an abnormal pupil, one eye (4.5%) had an abnormal IOL with a few particles on the surface of the IOL but no glistening, and 3 eyes (13.6%) had posterior capsular opacification (PCO); in the control group, one eye (5.0%) had an abnormal cornea, five eyes (25.0%) had abnormal IOLs [one eye (5.0%) had IOL calcification, and four eyes (20.0%) had IOL glistening], and one eye (5.0%) had PCO with posterior capsular folds and IOL tilt. There was no significant difference in PCO and IOL abnormality between the two groups (both P>0.05), but there was significant difference in the occurrence of IOL glistening (P=0.04). Conclusion: The long-term effect of A1-UV aspheric IOL on improving the UCDVA is stable and good, with high subjective satisfaction of patients, a low incidence of PCO, no glistening and good biocompatibility, over the postoperative 5 years. (Chin J Ophthalmol, 2021, 57: 41-47).

The relationship between angle kappa and astigmatism after phacoemulsification with implanting of spherical and aspheric intraocular lens.

Purpose:To determine the significance of any association between either change in angle kappa (K°) or the rectilinear displacement (L, mm) of the first Purkinje image relative to the pupil center and unexpected changes in astigmatism after phacoemulsification.Methods:Orbscan II (Bausch and Lomb) measurements were taken at 1, 2, and 3 months after unremarkable phacoemulsification in patients implanted with spherical (group 1, SA60AT, Alcon) or aspheric (group 2, SN60WF, Alcon) nontoric IOLs. The outputs were used to calculate L. Astigmatism, measured by autorefractometry and subjective refraction, was subjected to vector analysis (polar and cartesian formats) to determine the actual change induced over the periods 1–2 and 2–3 months postop.Results:Chief findings were that the mean (n, ±SD, 95%CI) values for L over each period were as follows: Group 1, 0.407 (38, ±0.340, 0.299–0.521), 0.315 (23, ±0.184, 0.335–0.485); Group 2, 0.442 (45, ±0.423, 0.308–0.577), 0.372 (26, ±0.244, 0.335–0.485). Differences between groups were not significant. There was a significant linear relationship between (A) the change in K (ΔK = value at 1 month-value at 2 months) and K at 1 month (x), where ΔK =0.668-3.794X (r = 0.812, n = 38, P = <0.001) in group 1 and ΔK = 0.263x -1.462 (r = 0.494, n = 45, P = 0.002) in group 2, (B) L and the J45 vector describing the actual change in astigmatism between 1 and 2 months in group 2, where J45 (by autorefractometry) =0.287L-0.160 (r = 0.487, n = 38, P = 0.001) and J45 (by subjective refraction) =0.281L-0.102 (r = 0.490, n = 38, P = 0.002), and (C) J45 and ΔK between 2 and 3 months in group 2, where J45 (by subjective refraction) =0.086ΔK-0.063 (r = 0.378, n = 26, P = 0.020).Conclusion:Changes in the location of the first Purkinje image relative to the pupil center after phacoemulsification contributes to changes in refractive astigmatism. However, the relationship between the induced change in astigmatism resulting from a change in L is not straightforward.

Age affects intraocular lens attributes preference in cataract surgery.

PURPOSE:The aim of this study is to analyze the effects of age on intraocular lens (IOL) attributes preference.MATERIALS AND METHODS:We enrolled 4213 eyes that underwent smooth phacoemulsification and IOL implantation between January 2005 and June 2018. Patients were subdivided into six groups according to their ages, i.e.,≤40, 41–50, 51–60, 61–70, 71–80, and ≥ 81 years old. The difference in preference of IOL attributes regarding age, gender, and year of surgery was analyzed separately. The analyzed IOL attributes included asphericity, astigmatism-correction, presbyopia-correction, and blue-blocking function.RESULTS:The patients averaged 68.3 ± 11.6 years old at the time of surgery. There was no significant difference in age between males and females. There were 1980 patients (47.0%) selected aspheric IOL, 822 patients (19.5%) selected multifocal (MF) IOL, 93 patients (2.2%) selected toric IOL, and 859 patients (20.4%) selected blue-blocking IOL. Adoption of aspheric and MF IOL increased significantly during the study (P < 0.001 for both attributes). There were more young patients selected aspheric and MF IOL (P < 0.001 for both), and the change in the trend of adoption over the years was also most significant in the young group (P < 0.001 for both). The proportion of patients that selected blue-blocking IOL decreased significantly after 2011 (P < 0.001). There was no gender preference in aspheric, MF, and toric IOL selection. However, there were more male patients selected blue-blocking IOL (P = 0.018).CONCLUSION:The adoption of IOLs with emerging technologies increased significantly over the years. Younger adults tended to adopt advanced technology IOL more than the older ones.

Misalignment and tilt effect on aspheric intraocular lens designs after a corneal refractive surgery.

PurposeTo numerically evaluate and compare the tolerance to misalignment and tilt of aspheric intraocular lenses (IOLs) designed for three eyes: with standard cornea and with simulated corneas after myopic and hyperopic laser ablation surgery.MethodsThree aspheric IOLs of +20.00 diopter (D) with different spherical aberration (SA) () values have been designed using a theoretical model eye. Drastic changes on the theoretical eye anterior corneal asphericity have been performed to simulate myopic and hyperopic refractive surgeries. The effect of IOL misalignment and tilt on the image quality has been evaluated using a commercial optical software design for the three eye models. Image quality was assessed from the modulation transfer function (MTF), root mean square (RMS) values of defocus, astigmatism, coma and spherical aberration (), and retinal images obtained from a visual simulator using an aleatory optotype of 0.00 LogMar visual acuity (VA).ResultsIOL misalignment and tilt reduced MTF values in general, and increased wavefront aberrations errors. Aberration-free IOLs maintained best the MTF values when misalignments were applied, together with good on-axis optical quality. IOLs with negative SA () correction decreased the MTF value under 0.43 for misalignments values higher than 0.50 mm with the three corneas. The effect of misalignment on RMS astigmatism and coma was correlated with the IOL SA () and with the three corneas.ConclusionsThis theoretical study shows that the largest degradation in image quality arises for the IOL with the highest amount of spherical aberration (). Moreover, it has been found that the aspherical design has a more influential role in misalignment tolerance than in tilt tolerance.

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.

Corneal Topography for Intraocular Lens Selection in Refractive Cataract Surgery

The purpose of this review is to evaluate the usefulness of corneal topography to select premium intraocular lenses (IOLs), including aspherical IOLs, toric IOLs, and multifocal IOLs, in refractive cataract surgery. Corneal topography can detect corneal regular astigmatism, corneal irregular astigmatism (higher-order aberrations [HOAs]) including spherical aberration, and corneal shape abnormalities after corneal refractive surgery. Surgeons can explain to the patients with significant corneal HOAs about its effect on postoperative visual function before surgery. Multifocal IOLs should not be selected for such eyes. For eyes with abnormal corneal shape, appropriate IOL power calculation formulae can be applied. In the case of toric IOLs, regular astigmatism and corneal HOAs should be checked. Before implanting an aspheric IOL, it is ideal to confirm spherical aberration of the cornea is not below the normal range. Because corneal HOAs, abnormal corneal shape after corneal refractive surgery, corneal regular astigmatism, and corneal spherical aberration increase postoperative refractive errors and poor vision quality with premium IOLs, corneal topography before cataract surgery is helpful in screening patients who are not appropriate candidates for premium IOLs.

Comparison of visual quality after implantation of A1-UV and SN60WF aspheric intraocular lens.

To compare the visual performance of pseudophakic eyes implanted with A1-UV and SN60WF aspheric intraocular lens (IOL), and to investigate the correlations between visual quality parameters and pupil size. This prospective comparative study included 105 eyes of 90 patients with age-related cataract who underwent uneventful phacoemulsification. The subjects were divided into two groups according to the implanted IOL type. Three months postoperatively, visual acuity and contrast sensitivity were measured, wave-front aberrations were assessed using a KR-1W aberrometer (Topcon), and objective optical quality parameters were performed using an optical quality analysis system-OQAS II (Visiometrics). Independent sample t-test and Spearman correlation analysis were used for data analysis. There were no significant differences found in visual acuity, contrast sensitivity and visual quality parameters between the two groups (P>0.05). The measured intraocular spherical aberration (SA) in A1-UV IOL eyes of -0.19±0.05 µm was close to the designed SA value of -0.20 µm. The modulation transfer function cutoff, Strehl ratio and OQAS values were negatively correlated with pupil size in both groups (P<0.01). The subjective and objective visual quality in pseudophakic eyes with A1-UV and SN60WF IOLs are comparable. For aspheric IOL eyes, visual quality decreases with increasing pupil size.

Analysis of the Effect of Intraocular Lens Implantation on Retinal Nerve and Postoperative Nursing Outcome Based on Ultrasound Imaging

Traumatic cataract is a common complication of ocular contusion. Caused by various forms of trauma, the course and prognosis of traumatic cataract are also different. Intraocular lens (IOL) implantation is the most effective treatment at the present time and can provide good visual quality and near, medium, and far vision. In this study, an adaptive medical ultrasound image denoising algorithm was constructed based on the biological vision mechanism and was applied to observe IOL implantation and postoperative care of 30 patients with traumatic cataract. Results showed that eyesight could be restored to the original healthy state after IOL implantation, and eyesight was close to normal 3 months after surgery. The corresponding noise pixel block of the noise reduction algorithm was obviously the lowest. A total of 30 patients (9 patients with contusion, 13 patients with intraocular foreign body, and 8 patients with perforation) were treated with aspheric and multifocal IOL to achieve the expected outcome. The noise reduction algorithm constructed in this study effectively reduced the speckle noise of ultrasound images, improved the clarity of ultrasound images, and achieved the effective observation of medical nursing outcome after traumatic cataract IOL implantation. After IOL implantation, the retinal nerves of patients with traumatic cataract were affected to different degrees.