Intraocular Lens Models Research Articles

Visual and optical performance of diffractive multifocal intraocular lenses with different haptic designs: 6 month follow-up

PurposeTo evaluate and compare the visual acuity outcomes and optical performances of eyes implanted with two diffractive multifocal intraocular lens (IOL) models with either a plate haptic design or a modified-C design.MethodsThis retrospective study comprised cataract patients who were implanted with either a plate haptic multifocal IOL model (AcrivaUD Reviol BB MFM 611 [VSY Biotechnology, Amsterdam, the Netherlands], group 1) or a modified-C haptic multifocal IOL model (AcrivaUD Reviol BB MF 613 [VSY Biotechnology, Amsterdam, the Netherlands], group 2) between June 2012 and May 2013. The 6 month postoperative visual acuity, refraction, defocus curve, contrast sensitivity, and wave-front aberration were evaluated and compared between these eyes, using different IOL models.ResultsOne hundred fifty-eight eyes of 107 patients were included in this study. Significant improvement in visual acuities and refraction was found in both groups after cataract surgery (P<0.01). The visual acuity and contrast sensitivity were statistically better in group 1 than in group 2 (P<0.01). No statistically significant difference in the corneal higher-order aberrations was found between the two groups (P>0.05). However, the ocular higher-order aberrations in group 2 were significantly greater than in group 1 (P<0.05).ConclusionAt 6 months postoperatively, both AcrivaUD Reviol BB MFM 611 IOL and AcrivaUD Reviol BB MF 613 IOL achieved excellent visual and refractive outcomes. The multifocal IOL model with plate haptic design resulted in better optical performances than that with the modified-C haptic design.

Estimation of the melatonin suppression index through clear and yellow-tinted intraocular lenses.

To estimate the melatonin suppression index (MSI), which may reflect the nonvisual photoreception function, through commercially available foldable, clear and yellow-tinted intraocular lenses (IOLs). The MSIs for 13 IOL models (6 clear IOLs, 7 yellow-tinted IOLs) with three lens powers were calculated based on previously reported data about the melatonin suppression spectrum, spectral intensity of a 20-W white fluorescent lamp and spectral transmission of IOLs in wavelengths from 300 to 800nm. The models tested were the SA60AT and SN60AT (Alcon Japan); the VA-60BBR, YA-60BBR, and NM-1 (Hoya); the AU6K and AN6K (Kowa); the N4-18B and N4-18YG (Nidek); the X-60 and NX-60 (Santen); and the KS-3Ai and KS-AiN (Staar Japan). The MSIs of the clear IOLs ranged from 1.12 to 1.18mWcm(-2)sr(-1) and those of the yellow-tinted IOLs from 0.74 to 1.01mWcm(-2)sr(-1). All yellow-tinted IOLs had significantly lower MSIs (P<0.0001-0.0021) than the clear IOLs; the %MSI cutoff values for yellow-tinted IOLs compared to the clear IOLs were 11.4-36.2%. The MSIs of the six clear IOLs did not differ based on lens powers (P=0.2159-0.6144). Except for one IOL model, all yellow-tinted IOLs had a lower MSI with higher lens powers compared to those with lower lens powers (P<0.0001-0.0055). Compared to phakic eyes (MSI, 1.03mWcm(-2)sr(-1)), the MSIs of the clear IOLs were higher (%MSI cutoff, -14.6 to -8.4%), whereas those of the yellow-tinted IOLs were lower (2.6-28.1%). Compared to aphakic eyes (MSI, 1.21mWcm(-2)sr(-1)), the MSIs of the clear (2.1-7.4%) and yellow-tinted (16.7-38.6%) IOLs were lower. Yellow-tinted IOLs absorb more circadian rhythm-associated light than clear IOLs. The difference in the lens power is significantly related to the MSI value in some yellow-tinted IOLs. To correlate the current data with the clinical relevance of these findings, the percent loss of the MSI leading to a circadian rhythm disorder needs to be clarified.

Macular thickness measured by optical coherence tomography in pseudophakic eyes with clear vs yellow implant

ObjectiveTo study the use of optical coherence tomography (OCT), for measuring the macular thickness variations produced over time in elderly pseudophakic subjects implanted with a clear intraocular lens (IOL) in one eye, and a yellow IOL in the other eye. MethodsMacular thickness measurements were obtained in the 36 eyes of 18 subjects over 65 years, with cataracts surgically removed from both eyes and implanted with different absorbance (clear and yellow) IOLs in two separate surgeries. Stratus-OCT was used to determine the macular thickness in two sessions with 5 years of difference. ResultsAfter 5 years of follow-up, the eyes implanted with clear IOLs revealed a significant decrease in macular thickness. However, in eyes implanted with yellow IOLs the macular thickness remained stable. The mean overall decrease in macular thickness in eyes implanted with clear IOLs was 5±8μm (p=0.02), and foveal thickness reduction was 10±17μm (p=0.02). ConclusionsThe macular thickness changes produced in eyes implanted with a yellow IOL differ from those with a clear IOL. These observations point to a possible protective effect of yellow IOL against the harmful effects of light in elderly pseudophakic subjects. However, studies with a longer follow-up are still needed to confirm that the protection provided by this IOL model is clinically significant.

In vitro optical performance of a new aberration-free intraocular lens

To assess the optical performance of the new EnVista intraocular lens (IOL). Four aspheric IOLs were evaluated; the new EnVista is one amoung them. This IOL, similarly to the Z-Flex HB and the Bi-Flex 1.8 667AB ones, has a neutral aspheric design, whereas the fourth IOL under test (AcrySof IQ IOL SN60WF) presents a negative spherical aberration (SA). The IOL's aberration patterns were measured in vitro, by setting them up on an optical bench. From these aberration-pattern data, the modulation transfer function (MTF), the average modulation values, and the points spread function (PSF) were calculated. Furthermore, in order to assess the potential optical quality that these IOLs would yield once they are implanted, an average corneal-aberration pattern was juxtaposed to the in-vitro profiles and the same parameters were calculated again. For the IOL-only scenario (ie, without including the corneal factor), it was the EnVista IOL, which is aberration-free that showed the higher MTF, PSF values. This was followed by the other two aberration-free IOL models. However, when the effect of an average corneal pattern was also taken into consideration, the AcrySof IQ IOL SN60WF always outperformed the other neutral-asphericity IOLs. The in-vitro optical performance of the EnVista IOL was good, but it decreases substantially in a whole-eye scenario, when the wavefront profile of an average cornea is added. Other designs with different degrees of SA should be considered for this IOL in order to surpass these results.

Espesor macular medido con tomografía de coherencia óptica en ojos pseudoafáquicos con implante amarillo vs. transparente

ObjectiveTo study the use of optical coherence tomography (OCT), for measuring the macular thickness variations produced over time in elderly pseudophakic subjects implanted with a clear intraocular lens (IOL) in one eye, and a yellow IOL in the other eye. MethodsMacular thickness measurements were obtained in the 36 eyes of 18 subjects over 65 years, with cataracts surgically removed from both eyes and implanted with different absorbance (clear and yellow) IOLs in 2 separate surgeries. Stratus-OCT was used to determine the macular thickness in 2 sessions with 5 years of difference. ResultsAfter 5 years of follow-up, the eyes implanted with clear IOLs revealed a significant decrease in macular thickness. However, in eyes implanted with yellow IOLs the macular thickness remained stable. The mean overall decrease in macular thickness in eyes implanted with clear IOLs was 5±8μm (P=.02), and foveal thickness reduction was 10±17μm (P=.02). ConclusionsThe macular thickness changes produced in eyes implanted with a yellow IOL differ from those with a clear IOL. These observation point to a possible protective effect of yellow IOL against the harmful effects of light in elderly pseudophakic subjects. However, studies with a longer follow-up are still needed to confirm that the protection provided by this IOL model is clinically significant.

Anterior and posterior capsular opacification with the Tecnis ZCB00 and AcrySof SA60AT IOLs: a randomised intraindividual comparison

PurposeTo evaluate and compare the 1-year postoperative levels of posterior capsule opacification (PCO) as well as the level of anterior capsule retraction and opacification (ACO) after implantation of two single-piece...

Follow-up Study of More Than 15 Years of an Angle-Supported Phakic Intraocular Lens Model (ZB5M) for High Myopia

This study confirmed the long-term outcomes of the ZB5M phakic intraocular lens (PIOL). To evaluate the potential long-term risk associated with ZB5M PIOL implantation. A retrospective, nonrandomized, consecutive cohort study of a total of 208 eyes implanted with ZB5M PIOLs at VISSUM Corporación Oftalmológica de Alicante between 1990 and 1996 identified through surgical records (208 eyes of 123 patients); 50 of these patients (97 eyes) had available records and follow-up. ZB5M PIOL implantation. To evaluate the incidence and onset of each complication during the follow-up and risk factors and causes for loss of visual acuity. Mean (SD) preoperative spherical equivalent refraction was -19.36 (6.7) diopters and at the end of follow-up, it was -1.4 (2.6) diopters. Mean (SD) best-corrected visual acuity at the preoperative visit was 0.35 (0.2) decimal and at the end of follow-up, 0.56 (0.3) decimal. Mean (SD) endothelial cell density preoperatively and at the end of follow-up was 2783 (787) cells/mm(2) and 1921 (672) cells/mm(2), respectively. The incidence of cataract during the follow-up was 0.010 eye-year (EY); cornea decompensation, 0.001 EY; ocular hypertension, 0.008 EY; pupil ovalization, 0.020 EY; uveitis, 0.001 EY; and retinal detachment, 0.002 EY. To our knowledge, this is the first study that describes the long-term outcomes and complications of ZB5M PIOLs and suggests increasing the postoperative follow-up examinations in patients older than 40 years, analyzing anterior chamber modifications, and recommends PIOL explantation in cases of an increase in the crystalline size.

Theoretical image performance with customized aspheric and spherical IOLs – when do we get a benefit from customized aspheric design?

Background & PurposeImplantation of an artificial intraocular lens (IOL) during cataract surgery significantly changes the balance of aberrations in the eye. We demonstrate the theoretical superiority of customized aspheric IOL designs over standard spherical IOLs for different values of corneal curvature, asphericity and axial length. MethodsFor a selected set of corneal surfaces we calculated a best-fit equiconvex spherical IOL. In a second step we customized the IOL back surface to correct the wavefront aberrations of the cornea. Then we calculated a quadric approximation of the IOL back surface to retrieve the aspheric parameters of the customized lens in terms of radius of curvature and asphericity/conic constant. The optical performance of the three IOL models was monitored in terms of lateral ray spread (LRS) at retinal plane for variations of corneal curvatures, asphericity and axial lengths of the pseudophakic eye. ResultsThe LRS of customized aspheric IOLs was significantly smaller compared to that of spherical IOLs (typically between 10 and 25dB). For high aspheric coefficients the LRS increased with spherical IOLs. With aspheric IOLs LRS was higher for steep corneas paired with high aspheric coefficients, mostly due to the fitting error of the quadratic function. For several combinations of corneal curvature and aspheric coefficients the focal point of the aspheric IOL was up to 400 times smaller than the spherical one. ConclusionThis study appeals to the reader for the potential benefit of customized aspheric IOL design instead of the principle of a ‘one size fits all’ aspheric coefficient as used currently in clinical practice. A benefit with customized IOLs is less depending from the axial length and can be achieved with corneas of a moderate prolate aspheric shape with an equal or more negative Q value than the average of -0.22. Longer eyes seem to benefit less than short eyes.

Imaging characteristics of delayed surface calcification in hydrophilic intraocular lens models

We report two cases of opacified explanted intraocular lenses (IOL).The first lens was explanted from a cataract patient, then treated in vitro with trypsin/ethylene-diamine-tetra-acetic acid. The second hydrophilic acrylic IOL was explanted from a patient who had undergone sulphur hexafluoride (SF6) gas endotamponade surgery to repair a retinal detachment.

In Vivo Chromatic Aberration in Eyes Implanted With Intraocular Lenses

To measure in vivo and objectively the monochromatic aberrations at different wavelengths, and the chromatic difference of focus between green and infrared wavelengths in eyes implanted with two models of intraocular lenses (IOL). EIGHTEEN EYES PARTICIPATED IN THIS STUDY: nine implanted with Tecnis ZB99 1-Piece acrylic IOL and nine implanted with AcrySof SN60WF IOL. A custom-developed laser ray tracing (LRT) aberrometer was used to measure the optical aberrations, at 532 nm and 785 nm wavelengths. The monochromatic wave aberrations were described using a fifth-order Zernike polynomial expansion. The chromatic difference of focus was estimated as the difference between the equivalent spherical errors corresponding to each wavelength. Wave aberration measurements were highly reproducible. Except for the defocus term, no significant differences in high order aberrations (HOA) were found between wavelengths. The average chromatic difference of focus was 0.46 ± 0.15 diopters (D) in the Tecnis group, and 0.75 ± 0.12 D in the AcrySof group, and the difference was statistically significant (P < 0.05). Chromatic difference of focus in the AcrySof group was not statistically significantly different from the Longitudinal chromatic aberration (LCA) previously reported in a phakic population (0.78 ± 0.16 D). The impact of LCA on retinal image quality (measured in terms of Strehl ratio) was drastically reduced when considering HOA and astigmatism in comparison with a diffraction-limited eye, yielding the differences in retinal image quality between Tecnis and AcrySof IOLs not significant. LRT aberrometry at different wavelengths is a reproducible technique to evaluate the chromatic difference of focus objectively in eyes implanted with IOLs. Replacement of the crystalline lens by the IOL did not increase chromatic difference of focus above that of phakic eyes in any of the groups. The AcrySof group showed chromatic difference of focus values very similar to physiological values in young eyes.

Intraocular Lens Calcification After Keratoplasty

To report calcification of intraocular lenses (IOLs) after various keratoplasty procedures. Clinical data of all cases with calcified IOLs after keratoplasty procedures were analyzed. A total of 6 explanted IOLs were analyzed with light microscopy before and after staining with 1% alizarin red and the von Kossa method. A total of 7 cases occurred after Descemet stripping automated endothelial keratoplasty, 1 case after deep anterior lamellar keratoplasty, and 2 cases after penetrating keratoplasty. Median time interval from keratoplasty to first notice of IOL opacification was 6.5 months (minimum 3 months, maximum 51 months). A total of 3 IOLs had been placed at the time of keratoplasty and 7 IOLs before keratoplasty. All affected IOLs were hydrophilic acrylic and comprised IOLs from at least 3 different polymer sources. Common clinical aspects were some amount of inflammation in the anterior chamber during the postoperative period and use of air at the end of surgery in 8 of the 10 cases. Histochemical analysis demonstrated the presence of fine granular deposits located within the very superficial optic material in all cases. The deposits stained positive for calcium with alizarin red and the von Kossa method. IOL calcification associated with keratoplasty in our series does not seem to be a problem related to a specific IOL model or polymer. The process of calcification may be mediated by inflammation, which also may be related to multiple injections of air into the anterior chamber.

Anterior segment optical coherence tomography in black‐on‐clear polypseudophakia

Anterior segment optical coherence tomography in black‐on‐clear polypseudophakia

Influence of +3.00 D and +4.00 D near addition on functional outcomes of a refractive multifocal intraocular lens model

To clinically evaluate different near additions (adds) (+3.00 diopters [D] and +4.00 D) of the M-flex 630F refractive multifocal intraocular lens (IOL). Departments of Ophthalmology, University of Heidelberg, Germany, and Lithuanian University of Health Sciences, Kaunas, Lithuania. Clinical prospective nonrandomized unmasked study. Preoperatively, cataract patients were assigned to receive bilateral +3.00 D IOLs, +4.00 D IOLs, or +3.00 D (dominant eye) and +4.00 D (nondominant eye) IOLs. Follow-up examinations were performed up to 6 months postoperatively and included refraction, visual acuity (near at 40 cm and distance), the defocus curve, contrast sensitivity, and a subjective questionnaire. Fifty-two patients were enrolled. No significant differences were found in the visual acuity results (P>.05). Four to 6 months postoperatively, the following median uncorrected and corrected distance visual acuity, uncorrected and distance-corrected near visual acuity, and corrected near visual acuity (logMAR) were found in all patients: -0.08, -0.12, 0.20, 0.10, and 0.10. Ninety-eight percent of patients reported being satisfied. The highest near peak versus the biggest intermediate decline in the median monocular defocus curves comparing +3.00 D and +4.00 D multifocal IOLs (logMAR) were 0.16 at 40 cm versus 0.22 at 33 cm (P=.24) and 0.38 at 66 cm versus 0.54 at 50 cm (P<.01). Compared with the +4.00 D add, the +3.00 D near add gave better intermediate results in the defocus curve without compromising distance or near visual acuity.

Bilateral reading performance of 4 multifocal intraocular lens models and a monofocal intraocular lens under bright lighting conditions

To compare changes in reading performance parameters after implantation of 4 multifocal intraocular lens (IOL) models and a monofocal IOL. Department of Ophthalmology, Paracelsus Medical University, Salzburg, Austria. Prospective randomized controlled clinical trial. Patients with bilateral cataract without additional ocular pathology were scheduled for bilateral implantation of Acri.Smart 48S monofocal, Acrysof Restor SN6AD3 apodized multifocal, AT LISA 366D diffractive multifocal, Tecnis ZMA00 diffractive multifocal, or Rezoom refractive multifocal IOLs. Bilateral corrected and uncorrected reading acuity, reading distance, mean and maximum reading speeds, and smallest log-scaled print size of a Radner reading chart were evaluated under bright lighting conditions (500 lux) using the Salzburg Reading Desk. Pupil size was not measured throughout the trial. The minimum follow-up was 12 months. The diffractive multifocal groups had significantly better uncorrected reading acuity and uncorrected smallest print size than the monofocal and refractive multifocal groups 1, 6, and 12months postoperatively. The diffractive IOL groups had comparable uncorrected reading distance of approximately 32 cm, which was larger in the monofocal group (38.9 ± 8.4 cm) and refractive multifocal group (37.1 ± 7.3 cm) at the last visit. Patients with diffractive IOLs could read print sizes of approximately 0.74 to 0.87 mm, which was much better than in the monofocal and refractive multifocal groups. The diffractive AT LISA IOL provided the best reading speed values (mean and maximum, corrected and uncorrected). Multifocal IOLs with a diffractive component provided good reading performance that was significantly better than that obtained with a refractive multifocal or monofocal IOL. Drs. Grabner and Dexl were patent owners of the Salzburg Reading Desk technology (now owned by SRD-Vision, LLC). No other author has a financial or proprietary interest in any material or method mentioned.

In vitro optical performance of nonrotational symmetric and refractive–diffractive aspheric multifocal intraocular lenses: Impact of tilt and decentration

To evaluate the optical quality of Acrysof Restor SN6AD1 refractive-diffractive +3.00 D and Lentis Mplus LS-312 nonrotational symmetric +3.00 D aspheric multifocal intraocular lenses (IOLs) and analyze the effect of tilt and decentration. University of Valencia, Valencia, and University of Murcia, Murcia, Spain. Experimental study. An artificial model eye was used to measure wavefront aberrations of both IOL models. The modulation transfer function (MTF) and point-spread function (PSF) were calculated for a 5.0 mm pupil and under 5 situations: centered, 0.2 mm and 0.4 mm decentered, and 2 degrees and 4 degrees tilted. The refractive-diffractive IOL had the highest MTF values at all spatial frequencies. Similarly, the PSF was worse for the refractive-diffractive IOL. The MTFs for the refractive-diffractive IOL decreased when the IOL was decentered or tilted, being more robust for tilting than decentration. The MTFs for the nonrotational symmetric IOL were similar under all testing conditions. Cutoff frequencies for the refractive-diffractive IOL were stable over the range of tilting studied and comparable with the cutoff when the IOL was centered (approximately 50 cycles per degree [cpd]). When the IOL was decentered, the cutoff frequency decreased by approximately 40 cpd. The nonrotational symmetric IOL cutoff frequencies for misalignment and tilt were low (approximately 30 cpd) and similar under all conditions. The refractive-diffractive IOL provided better optical quality than the nonrotational symmetric IOL. Tilt and decentration had a significant impact on optical quality with both IOLs, being more severe with the nonrotational symmetric IOL.

Visual acuity at intermediate distances after implantation of different models of intraocular lenses

Aim. To study the rehabilitative effect of treatment of cataracts by implanting trifocal refractive-diffractive soft intraocular lens MIOL-Record 3. Methods. 192 patients (216 eyes) who were operated on for cataract participated in the study. The first (main) group included 63 patients (72 eyes) in whom cataract extraction and implantation of the domestic trifocal refractive-diffractive monolithic (soft) intraocular lens MIOL-Record 3 was performed. The second group included 64 patients (70 eyes) in whom cataract extraction and implantation of the domestic bifocal refractive-diffractive lens MIOL-Accord was performed. The third group consisted of 65 patients (74 eyes) in whom cataract extraction and implantation of the domestic monofocal lens MIOL-2 was performed. Preoperative examination was performed the day before surgery, postoperative - after 7 days, 1, 3, 6 and 12 months. Results. The mean value of visual acuity at a distance of 50 cm without correction in the group of patients with MIOL-Record 3 1 month after surgery was 0.42±0.01 and was significantly higher than such in patients with MIOL-Accord and MIOL-2 - 0.14±0.01 and 0.1±0.001, respectively. A questionnaire survey revealed that in the group with MIOL-Record 3 additional correction with glasses is never used at the intermediate distance in 98.62% of the cases, in groups with MIOL-Accord - in 54.28%, and with MIOL-2 - in 25.68% of cases. Patients with MIOL-Record 3 were completely satisfied with the results of surgery in 70.84% of the cases, and in groups with MIOL-Accord and MIOL-2 - in 54.28, and 27.03% of cases, respectively. Conclusion. The conducted studies have established the best rehabilitative effect of the treatment of cataract during implantation of a trifocal refractive-diffractive intraocular lens MIOL-Record 3.

Calcification and Membrane Formation on the Surface of Intraocular Lenses in a Rabbit Model

Purpose: The aim of this study is to evaluate the calcification and membrane formation in different intraocular lenses (IOLs) models by implanting the IOLs in the subcutaneous plane of a Rabbit model.Design: Experimental study.Methods: IOLs were implanted subcutaneously in 13 Japanese albino rabbits for 1 month (n = 6), 3 months (n = 4) and 6 months (n = 3). Five kinds of IOLs were used, including three hydrophobic acrylic IOLs, the MA60AC (Alcon), ZA9003 (AMO) and X-60 (Santen), and two hydrophilic acrylic IOLs, the HP60M and MI60 (Bausch & Lomb). Scanning electron microscopy was used to observe the IOL optics. Energy dispersive x-ray spectroscopy and infrared spectroscopy were used to analyse any surface depositions on the optics, and the modulation transfer function was applied to evaluate the optical performance.Results: Membrane formation was noted to have occurred on the surfaces of the two hydrophobic acrylic IOLs (MA60AC and ZA9003) during the investigation period. The membrane components originated from a serum protein that most likely would be serum albumin. Calcification was noted to have occurred on the surfaces of the two hydrophilic IOLs. However, no calcification was observed on the hydrophobic IOLs, nor was there any membrane formation on the hydrophilic IOLs. The values for the MI60 were not measurable at all at 3 or 6 months. The values of the three hydrophobic IOLs were significantly better than the value for the HP60M at three and six months (p < 0.01).Conclusion: Calcification to the hydrophilic IOLs severely affected optical performance, whereas, membrane formation on the hydrophobic IOLs did not affect optical performance. The X-60 had the optics that best maintained long-term transparency.

Posterior capsular opacification and intraocular lens surface micro-roughness characteristics: An atomic force microscopy study

ObjectiveSurface roughness parameters of various intraocular lenses (IOLs) biomaterials using atomic force microscopy (AFM) are compared. Variation, if any, in the micro-roughness properties of different IOLs made up of the same biomaterial is also explored. Retrospective analysis of posterior capsular opacification (PCO) incidence has been followed up for a period of four years post IOL implantation to evaluate the correlation of PCO formation with surface roughness of IOLs. DesignExperimental materials study. Materials and participantsSurface characteristics of 20 different IOL models were assessed using AFM. These IOL models were made up of PMMA or HEMA or acrylic hydrophobic or acrylic hydrophilic or silicone. Retrospective analysis of PCO incidence in 3629 eyes of 2656 patients implanted with the same IOL models was performed. MethodsTopological characteristics of 20 different IOLs made up of 5 different biomaterials including (i) PMMA, (ii) HEMA, (iii) acrylic hydrophobic, (iv) acrylic hydrophilic and (v) silicone were evaluated using AFM in the tapping mode. Images were acquired with a resolution of 256×256 data points per scan at a scan rate of 0.5Hz per line and a scan size of 10×10μm. Rate of PCO formation in 3629 eyes of 2656 patients implanted with the five different IOL biomaterials was retrospectively analyzed. ResultsAFM images of IOL optic surfaces showed a collection of pores, grooves, ridges and surface irregularities. Surface roughness parameters of the IOL optics were significantly different on comparing lenses of different materials. Acrylic hydrophobic IOLs had minimum surface roughness while acrylic hydrophilic IOLs showed the highest surface roughness. Different IOL models of the same biomaterial showed varied topological roughness characteristics. Retrospective analyses of PCO formation rate after IOL implantation was carried out, which revealed that rate of PCO incidence, was directly proportional to the increase in surface micro-roughness of IOLs. ConclusionsAFM is a powerful technique for the topological characterization of IOLs. Acrylic hydrophobic IOLs showed minimum surface roughness properties as well as minimum PCO incidence over a period of four years post implantation. It is, therefore, tempting to consider acrylic hydrophobic IOLs over other IOL biomaterials as the ideal biocompatible material for lowering PCO incidence. These results suggest an urgent need for manufacturers to optimize the various steps involved in the fabrication of IOLs.

Visual function comparison of 2 aspheric multifocal intraocular lenses

To compare visual function after bilateral implantation of the multifocal Lentis Mplus LS-312 with a nonrotational symmetrical design (copolymer aspheric) or the Acrysof Restor SN6AD1 +3.0 D (hybrid aspheric) intraocular lens (IOL). Fernández-Vega Ophthalmological Institute, Oviedo, Spain. Comparative case series. Six months postoperatively, corrected distance visual acuity (CDVA), distance-corrected near visual acuity (DCNVA), the defocus curve, and photopic and mesopic contrast sensitivity with and without glare were measured. The mean CDVA was 0.02 ± 0.06 (SD) with the copolymer aspheric IOL and -0.06 ± 0.05 logMAR with the hybrid aspheric IOL (P=.07) and the mean DCNVA, 0.10 ± 0.06 and -0.09 ± 0.06 logMAR, respectively. The DCNVA was better with the hybrid aspheric IOL (P<.05). The defocus curve showed that the hybrid aspheric IOL provided better visual acuity from 0.00 to -5.00 diopter (D) vergences (P<.05) except for -1.00 and -1.50 D, where the IOLs were comparable. Contrast sensitivity was better with the hybrid aspheric IOL at 12 cycles per degree (cpd) and 18 cpd under photopic conditions (P<.05). No significant differences were found under mesopic conditions (P>.05). Both IOL models gave good and comparable visual acuity at distance. However, the hybrid aspheric IOL provided better DCNVA than the copolymer aspheric IOL. Intermediate vision was not as good as distance and near and was similar between the 2 IOLs. Photopic contrast sensitivity was better with the hybrid aspheric IOL at high spatial frequencies and comparable between IOLs at low frequencies and under mesopic conditions.

Prevention of Posterior Capsule Opacification With 3 Intraocular Lens Models: a Prospective, Randomized, Long-Term Clinical Trial

The aim of this prospective randomized study was to evaluate the impact of different sharp-edged intraocular lenses (IOLs) (hydrophobic acrylic or silicone) on posterior and anterior lens capsule opacification (PCO and ACO) at 3-year postoperative follow-up. A total of 96 eyes (89 patients) having a standard uncomplicated phacoemulsification procedure for age-related cataract were included in a prospective clinical study: 34 eyes with a 3-piece acrylic hydrophobic (AcrySof, MA3OBA), 32 eyes with a 1-piece acrylic hydrophobic (AcrySof, SA3OAL), and 30 eyes with a 3-piece silicone (CeeOn 911A) IOL. Visual acuity, capsulorrhexis/optic overlapping, ACO and PCO (using EPCO2000 system) were evaluated at 3-year follow-up. Capsulotomies performed by means of neodymium-yttrium-aluminum-garnet (Nd:YAG) laser were recorded. Three years after surgery, the grade of ACO of the capsulorrhexis rim area and the capsule/optic area was significantly greater in the silicone IOL group than in the acrylic IOL groups (P<0.05). During 3 postoperative years, there were no significant differences in the PCO values either in the entire IOL optic area or in the central 3-mm optic zone comparing the groups. Three years after surgery, 9% of eyes with a 3-piece acrylic IOL, 3.1% of eyes with a 1-piece acrylic IOL, and no case in the silicone IOL group had Nd:YAG capsulotomy (P>0.05). The 3-year follow-up after cataract surgery showed no difference in PCO development (EPCO2000) between acrylic hydrophobic and silicone sharp-edged IOLs. However, the need for Nd:YAG laser capsulotomy was higher in the acrylic IOL groups than the silicone IOL group, though the difference was not significant. ACO was greatest in the eyes with 3-piece silicone IOLs.