Tolerance to residual astigmatism of an isofocal intraocular lens.

PURPOSE: To evaluate the impact of residual astigmatism on the optical and visual performance of an enhanced-monofocal isofocal intraocular lens (EM Isopure, BVI medical, Belgium) compared to a monofocal one (Micropure, BVI medical, Belgium). METHODS: Laboratory investigation and prospective, comparative and randomized clinical study. Optical quality was assessed on an optical bench for 2.0, 3.0, and 4.5 mm pupils. The effect of residual astigmatism was investigated from through-focus images recorded with increasing amounts of regular positive astigmatism induced with a deformable mirror. To evaluate the impact of residual astigmatism, 28 eyes of 28 patients were randomly assigned to either group. Residual astigmatism was induced with positive and negative cylinder lenses at 90 and 180°. Visual acuity (VA) was measured at each step. RESULTS: The optical performance of both IOLs was quite similar for 2.0 and 3.0 mm pupils. For 4.5-mm pupil, the EM Isopure showed a significant reduction of its optical quality in comparison with the monofocal IOL. When visual performance was evaluated, no statistically significant differences were found for any power of induced astigmatism. More differences were found when positive induced astigmatism was compared within each group, and VA was better when the astigmatism was induced at 180° vs. 90°. The greatest differences were found for and induced positive astigmatism of + 1.50D (p = 0.009 for Isopure and p = 0.023 for Micropure). CONCLUSIONS: The tolerance to residual astigmatism of the EM Isopure lens is similar to that of a reference monofocal lens with pupils up to 3.5 mm.

Spatio-chromatic vision with multifocal diffractive intraocular lens.

BACKGROUND: This study aims to detect alterations in the spatio-chromatic pseudophakic vision produced by multifocal diffractive intraocular lenses (IOLs) and provides a physical interpretation. METHODS: In vitro characterization of the imaging performance of two diffractive IOLs: AT LISA Tri (Zeiss) and FineVision (PhysIOL) in on-bench model eye illuminated with red (R, 625 nm), green (G, 530 nm) and blue (B, 455 nm) lights. We used the metrics: energy efficiency (EE), area under the modulation transfer function, longitudinal chromatic aberration (LCA), and halo intensity. Through-focus (TF) analysis and calculation of the expected defocus curve under white (W) daylight were included. In vivo visual acuity (VA) of 50 pseudophakics (60 eyes) was assessed under W, R, G, B lights at far and near. Two clinical experiments evaluated LCA and R, G, B TF-EE effects on pseudophakic vision and their relative importance. RESULTS: Clinical mean VA values under W light agreed with the predicted values at far and near for both IOLs. LCA measurements and R, G, B TF-EE curves were consistent with their lens design based on the 0th and 1st diffraction orders operative for far and near vision, respectively. LCA effects were compensated at near but noticed at far (- 0.75 D under B light). We detected strong asymmetry in visual resolution depending on the object distance and the illuminating wavelength-red predominance at far, blue predominance at near-in consistency with the TF-EE measurements. CONCLUSIONS: Diffractive multifocal IOL designs produce asymmetries in the spatio-chromatic vision of pseudophakics beyond the alterations strictly due to LCA. VA asymmetry for far/near object distance under R and B illumination is clinically detectable in subjects implanted with IOLs with 0th and 1st diffraction orders for far and near vision, respectively. Such VA asymmetry cannot be explained solely from the influence of defocus, as would be derived from a chromatic difference of power, but mainly from the wavelength dependence of the EE.

Pitfalls of Using NIR-Based Clinical Instruments to Test Eyes Implanted with Diffractive Intraocular Lenses.

The strong wavelength dependency of diffractive elements casts reasonable doubts on the reliability of near-infrared- (NIR)-based clinical instruments, such as aberrometers and double-pass systems, for assessing, post-surgery, the visual quality of eyes implanted with diffractive multifocal intraocular lenses (DMIOLs). The results obtained for such patients when using NIR light can be misleading. Ordinary compensation for the refractive error bound to chromatic aberration is not enough because it only considers the best focus shift but does not take into account the distribution of light energy among the foci which strongly depends on the wavelength-dependent energy efficiency of the diffractive orders used in the DMIOL design. In this paper, we consider three commercial DMIOL designs with the far focus falling within the range of (-1, 0, +1)-diffractive orders. We prove theoretically the differences existing in the physical performance of the studied lenses when using either the design wavelength in the visible spectrum or a NIR wavelength (780 to 850 nm). Based on numerical simulation and on-bench experimental results, we show that such differences cannot be neglected and may affect all the foci of a DMIOL, including the far focus.

Beam-Shaping Extended Depth of Focus Intraocular Lens: Optical Assessment With Corneas of Increasing Spherical Aberration.

PURPOSE: To assess the optical quality and halo formation of a beam-shaping extended depth-of-focus (EDOF) intraocular lens (IOL) (AcrySof IQ Vivity; Alcon Laboratories, Inc) with corneas of long-range spherical aberration (SA) such as those resulting from myopic laser ablations. METHODS: The optical quality of the EDOF IOL and a reference monofocal IOL was evaluated with three corneas (A, B, and C, with SA =+0.135, +0.290, +0.540 µm, respectively, for a 5.15-mm pupil at the IOL plane). The through-focus modulation transfer function area (MTFa) curves were obtained between -5.00 and +2.00 diopters (D) defocus range. The halo was also assessed with the three corneas. RESULTS: Through-focus MTFa curves for a 4.5-mm IOL pupil showed a slight decrease in the maximum MTFa value provided by the EDOF IOL compared to the monofocal IOL in the three corneal situations (A: 45.9 vs 38.6 units; B: 41.1 vs 33.1 units, and C: 26.9 vs 23.8 units). For the 3.0-mm pupil, the EDOF IOL also had lower maximum MTFa than the monofocal IOL; however, the depth-of-focus increased to -2.20 D. With corneas A and B, the halo induced was of low energy with both IOLs. With cornea C, the EDOF IOL created a much larger and intense halo. CONCLUSIONS: The EDOF IOL provided a good distance optical performance and an extended range of focus of approximately 2.00 D, with a halo of low intensity when evaluated with a corneal SA similar to the one induced by a low to moderate myopic ablation. With a high myopic ablation, the halo induced would be of considerable size and energy. [J Refact Surg. 2023;39(2):95-102.].

Comparison of visual performance between two aspheric monofocal intraocular lens models.

CLINICAL RELEVANCE: It is important to distinguish between visual acuity, optical quality and quality of vision when outcomes obtained with intraocular lenses are evaluated. These parameters, that includeobjective and subjective tests, should be assessed to obtain results that are not biased. BACKGROUND: To assess the difference in visual and optical quality between two monofocal intraocular lens models. METHODS: : This was a prospective, parallel and randomised clinical study conducted at Miranza IOA, a private clinic in Madrid, Spain. Sixty patients were implanted bilaterally, 30 per group, with two aspheric IOLs with induced spherical aberration of -0.27 µm for Group A and -0.20 µm for Group B. Visual outcomes obtained at 1 and 3 months after surgery included both uncorrected (UCVA) and corrected monocular distance visual acuity (DCVA), objective scattering index (OSI), modulation transfer function (MTF) cut-off, Strehl Ratio (SR), contrast sensitivity defocus curve (CSDC), intraocular lens spherical aberration (SA), and longitudinal chromatic aberration of the eye. Activity limitations in daily life were assessed using CatQuest-9SF questionnaire. RESULTS: There were statistically significant differences for DCVA (0.04 LogMAR; p = .008) and SR (0.03; p = .003) between groups. Outcomes related to CSDC showed statistically significant differences for vergences between -0.50 D and +1.00 D (3 mm pupil) and for vergences of 0.00 D and +0.50 D (4.5 mm pupil) between groups. Overall, Group A showed better results regarding visual and optical quality, including a lower longitudinal chromatic aberration result in comparison to Group B. Patient satisfaction evaluated with CatQuest-9SF showed that Group A achieved better outcomes, although the differences were statistically significant only for the 'Reading text on television' item (p = 0.027). CONCLUSIONS: Both intraocular lens models showed excellent quantity of vision, optical and visual quality as well as high patient satisfaction. Despite this, the the Group A model provided slightly better outcomes than the Group B model.

Optical Assessment and Expected Visual Quality of Four Extended Range of Vision Intraocular Lenses.

PURPOSE: To assess the optical performance of four extended range of vision (ERV) intraocular lenses (IOLs) and predict the visual quality of the average pseudophakic patient. METHODS: Four ERV IOLs (LuxSmart, Bausch & Lomb; Vivity, Alcon Laboratories, Inc; Tecnis Eyhance, Johnson & Johnson Vision; and Isopure, PhysIOL) were inserted in an on-bench model eye. Their performance was assessed using through-focus modulation transfer function (MTF)-based metrics, through-focus point spread function, and halo analysis for three pupils (2.0, 3.0, and 4.5 mm). The expected visual acuity and the range of vision was estimated from the through-focus area under the MTF curve. A monofocal IOL (Tecnis ZCB00; Johnson & Johnson Vision) was included as reference. RESULTS: The Tecnis ZCB00 showed the highest image quality at far for all pupil conditions, closely followed by the Tecnis Eyhance. The LuxSmart and Vivity performed similarly in the intermediate range (-1.00 to -2.00 diopters [D]) with a 3.0-mm pupil and showed better performance than the other ERV IOLs for that range. All ERV lenses presented pupil dependent performance. All lenses reached normal expected visual acuity (0.0 logMAR) at far distance. The Tecnis ZCB00, Tecnis Eyhance, and Isopure decreased their expected visual acuity with defocus (0.1 logMAR at 66 cm) faster than the LuxSmart and Vivity (0.0 logMAR at 66 cm). The LuxSmart and Vivity produced greater halos than the Tecnis ZCB00, but they showed little change with larger pupils. The Isopure lens showed a pupil-dependent halo. CONCLUSIONS: The expected visual acuity decreased with the object distance differently, depending on the ERV design. The Vivity and LuxSmart lenses showed an expanded imaging capability (⩾ 0.50 D) with respect to a monofocal lens that may benefit intermediate vision. The Tecnis Eyhance and Isopure lenses showed more modest extensions that mainly rely on pupil constriction. [J Refract Surg. 2022;38(11):688-697.].

Optical and Clinical Outcomes of an Enhanced Monofocal Intraocular Lens for High Hyperopia.

PURPOSE: To evaluate the optical and clinical performance of an enhanced monofocal intraocular lens (IOL) (TECNIS Eyhance ICB00; Johnson & Johnson Vision) in patients with high hyperopia and a short axial length. METHODS: Power mapping, wavefront analysis, and the through-focus modulation transfer function area (TF-MTFa) were measured in vitro for three IOL powers (10.00, 20.00, and 30.00 diopters [D]). The clinical study included 22 patients with an axial length of less than 22.5 mm. Uncorrected (UDVA) and corrected (CDVA) distance visual acuity and binocular defocus curve were evaluated 6 months postoperatively. RESULTS: For the three IOL powers, the power mapping revealed an increase in positive power from the periphery to the center of the lens, providing an extra positive correction of 1.00 D for a 2-mm pupil size. The TF-MTFa curves showed only a peak of maximum MTFa at the distance focus. As the pupil size became smaller, there was a focus extension effect, providing an extended depth of focus of up to -1.50 D for a 2-mm pupil size. No significant dependency of the IOL base power on the power profile, wavefront, or optical quality was found. The clinical outcomes showed that all patients achieved a binocular CDVA of 0.1 logMAR or better. The mean visual acuity was better than 0.1 logMAR between +0.50 and -1.50 D of defocus. At a vergence of -2.00 D, the visual acuity was 0.11 ± 0.13 logMAR. CONCLUSIONS: The monofocal enhanced IOL provided good distance optical and visual quality and optimal visual acuity up to an intermediate-near vision distance of 50 to 40 cm in patients with high hyperopia and a short axial length. [J Refract Surg. 2022;38(9):572-579.].

Optical and Clinical Outcomes of an Extended Range of Vision Intraocular Lens.

PURPOSE: To assess the in vitro optical quality and halo formation of the AcrySof IQ Vivity intraocular lens (IOL) (Alcon Laboratories, Inc) and to evaluate the clinical outcomes in patients who had bilateral implantation of this IOL. METHODS: The optical quality was evaluated with the PMTF optical bench (Lambda-X). Through-focus modulation transfer function area (MTFa) curves between -5.00 and +2.00 diopters (D) were obtained for 3- and 4.5-mm pupil apertures. The halo was assessed in vitro with a test bench. The clinical study included 30 patients. Uncorrected (UDVA) and corrected (CDVA) distance visual acuity and binocular defocus curve were evaluated 6 months postoperatively. RESULTS: The through-focus MTFa curve for the 4.5-mm pupil size showed only one peak at distance focus (38.4 units). For the 3-mm pupil size, the through-focus MTFa showed a lower peak of MTFa (28.9 units), located at -0.70 D, and an extended depth of focus up to -2.20 D. The halo formed was larger and more intense compared to a standard monofocal IOL. The clinical outcomes at 6 months revealed satisfactory visual acuity outcomes. All patients achieved a binocular CDVA of 0.1 logMAR or better. The mean visual acuity was better than 0.2 logMAR between +1.00 and -2.00 D of defocus. At a vergence of -2.50 D, the visual acuity was 0.31 ± 0.09 logMAR. CONCLUSIONS: The AcrySof IQ Vivity IOL provided good distance optical and visual quality and an extended range of focus of approximately 2.00 D, obtaining an optimal or functional visual acuity up to 50 to 40 cm. The halo formed was low intensity overall, but higher intensity than a monofocal IOL. [J Refract Surg. 2022;38(3):168-176.].

Pupil size differences between female and male patients after cataract surgery.

PURPOSE: To evaluate the changes in pupil diameter in women and men after cataract surgery. The correlation of pupillary changes with the variables age and anterior chamber depth will be analyzed. METHODS: The values of 109 randomized eyes who underwent cataract surgery were obtained and divided into two groups, 71 women and 38 men. Pupil diameter was measured preoperatively and 3-months postoperatively using the pupillometer software of the Topolyzer Vario (Wavelight Laser Technologie AG). Anterior chamber depth was obtained with Pentacam® (Oculus). Differences in pupillary diameters were investigated and correlations with age and anterior chamber depth were analyzed. RESULTS: For mesopic pupils, the male group had greater reduction in their postoperative pupillary diameter, -0.56 mm (-12.4%), than the female group, -0.38 mm (-8.2%), P = 0.025. Photopic postoperative pupils reduced to a lesser extent, yet more in men than in women (-0.11mm [-4.5%] vs. -0.04 [-1.6%], P = 0.048). Weak significant negative correlation was found between photopic pupillary changes in women with age (r = -0.24, P = 0.041), and positive correlation for mesopic pupillary changes in men with age (r = +0.34, P = 0.039). CONCLUSIONS: Patients experience pupil reduction after cataract surgery in general, but more in men than in women and for both photopic and mesopic lighting conditions. The differences are statistically significant and have moderate clinical relevance. Concerning pupillary changes, weak but opposite sign correlations were found between male/female gender and age. Trial registration number at ClinicalTrials.gov Identifier: NCT04286646.

Impact of Lens Material on Objective Refraction in Eyes with Trifocal Diffractive Intraocular Lenses.

PURPOSE: Compare subjective (Rx) and objective (ObjRx) refractions outcomes with two autorefractors models and an aberrometer in eyes implanted with a hydrophobic trifocal IOL (FineVision POD F GF, Physiol, Liége, Belgium) and a hydrophilic one (FineVision POD F, Physiol, Liége, Belgium). METHODS: Prospective comparative cohort study, with 100 subjects randomly assigned to either the POD F group (n = 50) or the POD F-GF group (n = 50). Postoperative eye examinations at 1-month visit included seven result sets, one for each assessment method: Rx, AR (automated refraction measured with the autorefractor KR8800), WF-P (Zernike-coefficients-based objective refraction, photopic pupil size), WF-M (Zernike-coefficients-based objective refraction, mesopic pupil size), WF-4 (Zernike-coefficients-based objective refraction, 4 mm pupil), OPD-C (automated refraction measured with the aberrometer OPD in the central pupil/photopic conditions), and OPD-M (automated refraction measured with the aberrometer OPD under mesopic conditions). RESULTS: Mean differences between ObjRx and Rx reached statistical significance for sphere and spherical equivalent (M) only with OPD-C in the POD F-GF group. All ObjRx methods showed significant differences with Rx in the POD F group, with some values differing by more than 0.50 D (-0.58 D in M for the WF-P). Bland Altman plots showed better agreement for the astigmatic components, and for sphere and spherical equivalents in both IOL groups measured with AR and OPD-M. CONCLUSIONS: None of the objective methods of refraction evaluated in this study were as reliable as the subjective refraction, irrespective of the lens material, but POD F-GF ObjRx seems to differ less with Rx than POD F ObjRx values.

Optical design and performance of a trifocal sinusoidal diffractive intraocular lens.

Two theoretical sinusoidal diffractive profile models to build up a trifocal intraocular lens (IOL) are analysed. Topographic features of the diffractive zones such as their shape, step height and radii, as well as the energy efficiency (EE) of the foci, depends on the particular model, and are compared to the ones experimentally measured in a trifocal lens that claims to be designed with a generic sinusoidal diffractive profile: the Acriva Trinova IOL (VSY Biotechnology, The Netherlands). The topography of the IOL is measured by confocal microscopy. The EE is experimentally obtained through-focus with the IOL placed in a model eye. The experimental results match very accurately with one of the theoretical models, the optimum triplicator, once that a spatial shift in the sinusoidal profile is introduced in the model.

Through-Focus Energy Efficiency and Longitudinal Chromatic Aberration of Three Presbyopia-Correcting Intraocular Lenses.

Purpose: To compare the chromatic performance of the Bausch & Lomb Versario 3F trifocal intraocular lens (IOL) with the PhysIOL FineVision MicroF trifocal IOL and the Johnson & Johnson Vision TECNIS Symfony ZXR00 extended range of vision (ERV) IOL. Methods: The through-focus energy efficiency (TF-EE) was measured in vitro with red (R), green (G), and blue (B) wavelengths and was used to obtain the focus powers and longitudinal chromatic aberrations (LCAs) for each IOL. Other metrics, derived from the RGB TF-EE curves, were assessed for a more complete description of the chromatic performance of the IOLs. Results: Both of the trifocal IOLs, although not specifically designed to tackle chromatic aberrations, showed acceptable LCA (≤0.50 D) in all foci with more balanced R and B efficiencies of their foci. Despite having the lowest TF-EE value at all foci, the Versario 3F demonstrated the most balanced chromatic performance with the smoothest energy transition among all foci and the smallest chromatic span. The Symfony lens effectively reduced LCA at distance and intermediate foci (≤0.36 D), despite the unbalanced and asymmetric R and B efficiencies at its foci. Conclusions: To fully describe the chromatic performance of an IOL it is necessary to take into account not only the LCA but also the RGB TF-EE and chromatic span. This comprehensive analysis suggests that, in comparison with the other IOLs under study, the Versario 3F lens might contribute to further mitigating the impact of chromatic aberration. Translational Relevance: The in vitro bench testing of the optical properties of modern presbyopia-correcting intraocular lenses (more specifically in this work, the polychromatic through-focus energy efficiency and longitudinal chromatic aberration) provides objective and complementary information that helps to interpret the visual quality outcomes of pseudophakic patients obtained in clinics.

Optical Performance of a Monofocal Intraocular Lens Designed to Extend Depth of Focus.

PURPOSE: To test the performance of a new monofocal intraocular lens, intended to extend depth of focus (Tecnis Eyhance, ICB00; Johnson & Johnson Vision, Inc) (ICB-IOL), in comparison to a standard monofocal IOL (Tecnis 1-piece, ZCB00; Johnson & Johnson Vision, Inc) (ZCB-IOL) of the same platform and material. METHODS: Assessment of the optical performance of the two IOLs was made in vitro using an optical test bench with a model eye. The spherical aberration, modulation transfer function (MTF), and area under the MTF (MTFa) were obtained for pupil sizes ranging from 2 to 5 mm. Through-focus MTFa curves between -3.00 and +1.00 diopters (D) were obtained with three pupil sizes (2, 3, and 4.5 mm). Halo formation was also assessed for both lenses. RESULTS: The ICB-IOL had slightly worse optical quality at its best focus (ie, lower MTF scores at distance vision) and more negative spherical aberration than the ZCB-IOL for pupils ranging from 2 to 3 mm. The maximum of the through-focus MTFa curve of the ICB-IOL with a 2-mm pupil shifted to a myopic defocus of -0.50 D. For larger pupils (≥ 3.5 mm), there were no differences in spherical aberration, MTF scores, and halo energy between the two lenses. CONCLUSIONS: The new ICB-IOL is a modified monofocal lens with 0.50 D of additional power in its central 2-mm zone and more negative spherical aberration values, which induce a myopic shift of the maximum of optical quality and could improve intermediate vision. For pupils larger than 3.5 mm, there were no differences between IOLs. The new ICB-IOL design would produce photic phenomena comparable to a standard IOL. [J Refract Surg. 2020;36(9):625-632.].

Equivalence of two optical quality metrics to predict the visual acuity of multifocal pseudophakic patients.

This article studies the relationship between two metrics, the area under the modulation transfer function (MTFa) and the energy efficiency (EE), and their ability to predict the visual quality of patients implanted with multifocal intraocular lenses (IOLs). The optical quality of IOLs is assessed in vitro using two metrics, the MTFa and EE. We measured them for three different multifocal IOLs with parabolic phase profile using image formation, through-focus (TF) scanning, three R, G, B wavelengths, and two pupils. We analyzed the correlation between MTFa and EE. In parallel, clinical defocus curves of visual acuity (VA) were measured and averaged from sets of patients implanted with the same IOLs. An excellent linear correlation was found between the MTFa and EE for the considered IOLs, wavelengths and pupils (R2 > 0.9). We computed the polychromatic TF-MTFa, TF-EE, and derived mathematical relationships between each metrics and clinical average VA. MTFa and EE proved to be equivalent metrics to characterize the optical quality of the studied multifocal IOLs and also in terms of clinical VA predictability.

Comparison of visual and optical quality of monofocal versus multifocal intraocular lenses.

OBJECTIVE: To compare visual quality in patients implanted with Tecnis® monofocal (ZCB00) and multifocal (ZMB00) intraocular lenses taking into account their optical quality measured in vitro with an eye model. METHODS: In total, 122 patients participated in this study: 44 implanted with monofocal and 78 with multifocal intraocular lenses. Measurements of visual acuity and contrast sensitivity were performed. The optical quality of the intraocular lenses was evaluated in three image planes (distance, intermediate and near) using an eye model on a test bench. The metric considered was the area under the curve of the modulation transfer function. RESULTS: Optical quality at the far focus of the monofocal intraocular lens (area under the curve of the modulation transfer function = 66.97) was considerably better than that with the multifocal lens (area under the curve of the modulation transfer function = 32.54). However, no significant differences were observed between groups at the distance-corrected visual acuity. Distance-corrected near vision was better in the multifocal (0.15 ± 0.20 logMAR) than that in the monofocal group (0.43 ± 0.21 logMAR, p < 0.001), which correlated with the better optical quality at near reached by the multifocal intraocular lens (area under the curve of the modulation transfer function = 29.11) in comparison with the monofocal intraocular lens (area under the curve of the modulation transfer function = 5.0). In intermediate vision, visual acuity was 0.28 ± 0.16 logMAR (multifocal) and 0.36 ± 0.14 logMAR (monofocal) with p = 0.014, also in good agreement with the values measured in the optical quality (area under the curve of the modulation transfer function = 10.69 (multifocal) and 8.86 (monofocal)). The contrast sensitivity was similar in almost all frequencies. Pelli-Robson was slightly better in the monofocal (1.73) than in the multifocal group (1.64; p = 0.023). CONCLUSION: Patients implanted with multifocal ZMB00 achieved a distance visual acuity similar to those implanted with monofocal ZCB00, but showed significantly better intermediate and near visual acuity. A correlation was found between intraocular lenses' optical quality and patients' visual acuity. Contrast sensitivity was very similar between the multifocal and monofocal groups.

Clinical assessment of chromatic aberration in phakic and pseudophakic eyes using a simple autorefractor.

We describe a psychophysical method and a simple setup - an autorefractor with a Scheiner disc, sequentially illuminated with red and blue lights - for the clinical assessment of the longitudinal chromatic aberration (LCA) in phakic and pseudophakic patients. This method applies to the unaccommodated eye, even in the presence of positive or negative refractive errors and astigmatism. It measures the chromatic difference of refraction as an estimate of LCA. We built a proof of concept from inexpensive and off-the-shelf optomechanical components with which we obtained the preliminary clinical results presented in the paper. We considered one control group of phakic patients and three groups of pseudophakic patients with monofocal implants of different designs and materials. The results, satisfactory and consistent with those reported by other researchers in related works, demonstrate the method and system feasibility.

Visual acuity of pseudophakic patients predicted from in-vitro measurements of intraocular lenses with different design.

The optical quality of a set of IOLs (modeling set: one monofocal and two bifocals) was assessed through focus by the area under the modulation transfer function (MTFa) metric and related to the visual acuity (VA) defocus curves of pseudophakic patients implanted with said IOLs. A non-linear relationship between the MTFa and clinical VA was obtained with an asymptotic limit found to be the best VA achievable by the patients. Two mathematical fitting functions between clinical VA and MTFa were derived with high correlation coefficients (R2≥0.85). They were applied to the MTFa obtained from a different set of IOLs with advanced designs (trial set: one extended range of vision -ERV-, one trifocal ERV and one trifocal apodized) to predict VA versus defocus of patients implanted with these IOLs. Differences between the calculated VA and the clinical VA for both fitting models were within the standard deviation of the clinical measurements in the range of -3.00 D to 0.00 D defocus, thus proving the suitability of the MTFa metric to predict clinical VA performance of new IOL designs.

Patient-Perceived and Laboratory-Measured Halos Associated with Diffractive Bifocal and Trifocal Intraocular Lenses.

PURPOSE: To examine and assess the halos generated in distance vision by multifocal intraocular lenses (IOLs) using both in vitro objective and in vivo subjective methods. SETTING: The objective method was carried out in the optics laboratory of the Applied Optics and Image Processing Group (Universitat Politècnica de Catalunya -Barcelona). The psychophysical and subjective methods were carried out in the Instituto de Oftalmología Avanzada Madrid Innova Ocular. DESIGN: Optical bench results and prospective evaluation of consecutive cases. METHODS: The IOLs examined were TECNIS®one-piece bifocals with addition powers of +4.00 D, +3.25 D, and +2.75 D and the trifocals AT-LISA-tri® and FineVision®. In the objective assessment, we examined halos around the far focus images of a pinhole formed by each IOL in an optical bench. For the in vivo study, we recruited 100 patients who had been bilaterally implanted one month earlier with the IOLs under study. Participants were subjected to psychophysical halometry (Halo v1.0) on the eye with better, distance-corrected, visual acuity and were required to subjectively grade halos by responding to the question "How much do halos bother you?" RESULTS: The objective method revealed that the halo size increased with addition power and that the two trifocals gave rise to a double-halo pattern. Scores in the halometry also indicated a direct relationship between the halo size and addition power. The subjective results indicated fewer complaints about halos associated with the trifocal than bifocal IOLs. CONCLUSIONS: The addition power of the tested IOLs affected both laboratory-measured and patient-perceived halos. Trifocal lenses generated fewer complaints about halos. Precise: Multifocal intraocular lenses (MIOLs) give rise to halos observed by patients under conditions of dim lighting. This study compares laboratory characterized halos generated by five MIOLs with patient-perceived halos.