Quality In Pseudophakic Eyes Research Articles

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.

Peripheral image quality in pseudophakic eyes.

The purpose of this work was to evaluate peripheral image quality in the pseudophakic eye using computational, physical, and psychophysical methods. We designed and constructed a physical model of the pseudophakic human eye with realistic dimensions using a corneal phantom and a board-only camera that was pivoted around an axis that matched the anatomical center of a human retina, assuming a radius of curvature of 12 mm, while it was submersed in a 23.4 mm long water filled chamber to emulate human ocular axial length. We used this optical setup to perform direct recording of the point spread function (PSF) and the associated retinal images for a commercial intraocular lens (IOL). Additionally, psychophysical tests were carried out to investigate the impact of the off-axis astigmatism in peripheral visual performance, where spectacle-induced astigmatism simulated the pseudophakic conditions in healthy subjects. Our findings using the physical eye model confirm the existence of large amounts of astigmatism in the periphery of the pseudophakic eye. The psychophysical tests revealed a significant reduction of detection sensitivity in the peripheral visual field. The latter suggests that off-axis astigmatism in patients implanted with IOLs may have performance and safety implications for activities requiring efficient peripheral vision.

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

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

Optical quality evaluation of pseudophakic eyes implanted different materials of IOL by optical quality analysis system

Background Phacoemulsification with IOL implantation can reduce the light scattering caused by cataract, but many patients with IOLs implantation complained of glare or blurred vision.IOLs from different materials will affect IOL refractive index (RI) and optical design, which affect the value of scattered light of IOLs implantation. Objective This study was to analyze the effect of IOL materials on optical quality in pseudophakic eyes with optical quality analysis system (OQAS). Methods The clinical data of 95 eyes from 65 patients with age-related cataract who received phacoemulcification with IOL implantation in Tianjin Eye Hospital from March to Octomber were retropectively analyzed.Three types of IOL, including AR40e, Acrysof SA60AT and Rayner 620H, were implanted in 32 eyes, 30 eyes and 33 eyes, respectively.The visual quality indexes were detected and evaluated using OQAS, including uncorrected distance visual acuity (UCDVA, LogMAR), objective scatter index (OSI), modulation transfer function cut off (MTF cut off), strehl ratio (SR), Profile width at 50% point scatter function (PSF), Profile width at 10% PSF and contrast visual acuity under the 100%, 20%, 9% contrasts. Results The UCDVA was ≥0.3 in the eyes of AR40e group, SA60AT group and 620H group 1 month after surgery.No significant difference was found in the best corrected distance visual acuity (BCDVA, LogMAR) among three groups (F=1.362, P=0.246). The OSI was 1.72±1.11, 1.89±1.07 and 2.13±1.13 in the AR40e group, SA60AT group and 620H group, with a significant difference among the groups (F=3.638, P=0.045), and the OSI was significantly lower in the AR40e group than that in the SA60AT group or 620H group (both at P<0.05). No considerable difference in MTF cut off among the groups (F=2.401, P=0.192). The SR value was significantly elevated and the PSF at both 50% and 10% was declined in the AR40e group compared with the SA60AT group and 620H group (all at P<0.05). A significant difference was found in 9% contrast visual acuity among the three groups (F=3.866, P=0.038), and 9% contrast visual acuity was better in the AR40e group than that in the SA60At group or the 620H group (both at P<0.05). Negative correlations were found betwee OSI and BCDVA in the AR40e group, SA60AT group and 620H group (r=-0.275, P=0.041; r=-0.287, P=0.042; r=-0.233, P=0.037). Conclusions OQAS can evaluate optical quality of cataract patients after opeartion objectively.Material and RI of IOL have a great effect on visual quality after phacoemulcification with IOL implantation, especially under the low contrast environment.The operated eyes implanted hydrophobic acrylic IOLs with a lower RI can get better optical quality in comparison with the eyes implanted hydrophilic IOLs. Key words: Pseudophakia; Lens implantation, intraocular; Acrylic resins; Hydrophobic and hydrophilic interactions; Scattering, radiation; Contrast sensitivity; Visual acuity; Refraction, ocular

Effect of high-order aberrations and scattered light on visual quality in pseudophakic eyes with aspheric monofocal IOLs

Background High order aberrations and scattered light may be the main influencing factors of visual quality after phacoemulsification combined the aspherical IOL implantation.However, the study on objectively assessing the impact of them is little. Objective This study was to assess the impact of high order aberrations and scattered light on visual quality after phacoemulsification combined the aspherical IOL implantation. Methods A series cases-observational study was performed.Sixty-seven eyes of 53 patients who finished phacoemulsification and aspherical IOL implantation for at least 3 months in Tianjin Eye Hospital from February to August 2014 were enrolled.The root mean square (RMS) of total aberrations and high order aberrations was measured under the 4 mm pupil diameter with i-Trace aberrometer, including general high order aberrations, spherical aberrations, coma, and trefoil of entire eye, cornea and internal optics.The correlations between ocular aberrations and corneal or internal optic aberrations were analyzed.Objective scatter index (OSI) and objective visual quality parameters were measured, including MTF cut off frequency (MTF cut off), strehl ratio (SR) and OQAS values (100%OV, 20%OV, 9%OV) with OQASⅡ, and the correlations between the objective visual quality parameters and OSI, ocular aberrations, corneal aberrations or internal optic aberrations were analyzed.In addition, the correlations between OSI and ocular, corneal or internal optic aberrations were evaluated.Writen informed censent was obtained from each patient before entering the study. Results Ocular aberrations were significantly positively correlated with corneal or internal optic aberrations (r=0.255-0.586, all at P<0.05; r=0.582-0.907, all at P<0.01), and the associations between internal optic and ocular aberrations was stronger than those between corneal and ocular aberrations.The objective visual quality parameters were negatively correlated with ocular, corneal and internal optic aberrations (r=-0.247- -0.675, all at P<0.05; r=-0.245- -0.497, all at P<0.05; r=-0.246- -0.513, all at P<0.05)as well as with OSI(r=-0.620--0.781, all at P<0.01). Most of the associations between internal optic aberrations and objective visual quality parameters were stronger than those of corneal aberrations.Furthermore, ocular, corneal and optical aberrations were all positively correlated with OSI (r=0.396-0.727, all at P<0.01; r=0.320-0.522, all at P<0.05; r=0.319-0.598, all at P<0.01). Conclusions High order aberrations and scattered light seem to interact with objective visual quality in aspherical IOL implanted eyes, and the correlation between internal optic aberrations and ocular aberrations tends to be stronger than that of corneal aberrations. Key words: Cataract; Aspherical intraocular lens; Aberration; Scattered light; Visual quality

Simulation of the Through-Focus Modulation Transfer Functions According to the Change of Spherical Aberration in Pseudophakic Eyes

To evaluate the effects of spherical aberration (SA) correction on optical quality in pseudophakic eyes, we simulated the optical quality of the human eye by computation of the modulation transfer function (MTF). We reviewed the medical records of patients who underwent cataract surgery in Asan Medical Center, retrospectively. A Zywave aberrometer was used to measure optical aberrations at 1-12 postoperative months in patients with AR40e intraocular lens implants. The MTF was calculated for a 5 mm pupil from measured wavefront aberrations. The area under the MTF curve (aMTF) was analyzed and the maximal aMTF was calculated while changing the SA ( $-0.2{\sim}+0.2{\mu}m$ ) and the defocus (-2.0 ~ +2.0 D). Sixty-four eyes in 51 patients were examined. The maximal aMTF was $6.61{\pm}2.16$ at a defocus of $-0.25{\pm}0.66D$ with innate SA, and $7.64{\pm}2.63$ at a defocus of $0.08{\pm}0.53D$ when the SA was 0 (full correction of SA). With full SA correction, the aMTF increased in 47 eyes (73.4%; Group 1) and decreased in 17 eyes (26.6%; Group 2). There were statistically significant differences in Z(3, -1) (vertical coma; P = 0.01) and Z(4, 4) (tetrafoil; P = 0.04) between the groups. The maximal aMTF was obtained at an SA of $+0.01{\mu}m$ in Group 1 and an SA of $+0.13{\mu}m$ in Group 2. Optical quality can be improved by full correction of SA in most pseudophakic eyes. However, residual SA might provide benefits in eyes with significant radially asymmetric aberrations.

Influence of different acrylic intraocular lens materials on optical quality of vision in pseudophakic eyes

To analyze the effect of hydrophobic and hydrophilic acrylic intraocular lens (IOL) material on the optical quality in pseudophakic eyes with a clear posterior capsule and assess in vitro forward light scatter of these IOLs. St. Thomas' Hospital, London, United Kingdom. Comparative case series. Eyes with a hydrophobic or hydrophilic acrylic IOL and a clear posterior capsule within the central 4.0 mm at least 3 months postoperatively were identified from 2 ongoing studies. Data on 100% and 9% logMAR corrected distance visual acuities (CDVA) and total eye aberrations with a 4.0 mm pupil were collected. The 10% and 50% point-spread function (PSF) values of double-pass measurements were collected. In vitro forward light scattering was analyzed for the IOL models using a standardized laboratory technique. Twenty-eight eyes had hydrophilic IOLs, and 43 had hydrophobic IOLs. There was no significant difference in IOL power, postoperative spherical equivalent, or 100% logMAR CDVA between hydrophilic IOLs and hydrophobic acrylic IOLs. Nine percent logMAR CDVA (P=.000), 10% PSF (P=.005), 50% PSF (P=.008), and Zernike polynomial 4 (P=.000) were significantly different between the IOL groups. Although in vitro forward-scatter levels were low in both groups, hydrophilic IOLs had more forward scatter. Hydrophobic acrylic IOLs gave better low contrast visual acuity. Even within the acrylic subgroup, the optical quality varied significantly. The IOL material is an important factor influencing the optical quality of vision with different acrylic IOLs.

Aspheric intraocular lenses enhance contrast sensitivity

Evaluation of: Pandita D, Raj SM, Vasavada VA, Vasavada VA, Kazi NS, Vasavada AR. Contrast sensitivity and glare disability after implantation of AcrySof IQ natural aspherical intraocular lens: prospective randomized masked clinical trial. J. Cataract Refract. Surg. 33, 603–610 (2007).Intraocular lens (IOL) design is one of the major factors influencing visual function in pseudophakic eyes. Eyes implanted with a spherical IOL showed a reduction in the optical quality, caused, in part, by the increased positive spherical aberration of the IOL. Aspheric IOLs with negative spherical aberrations have been developed to compensate for the positive spherical aberrations of the cornea. Thus, aspheric IOLs have been used to increase the optical quality of pseudophakic eyes and, consequently, their visual quality. The paper under evaluation offers the results of a study assessing the contrast sensitivity and glare disability, as patient’s visual performance indexes, after implantation of an aspheric IOL. This study demonstrates that eyes implanted with the AcrySof® IQ aspheric IOL had significantly higher contrast sensitivity than those spherical IOLs under mesopic conditions, with and without glare.

Wavefront-customized intraocular lenses.

Recent advances in ocular wavefront measurement and in intraocular lens materials and manufacturing methods have brought cataract surgery to the brink of a period in which customized correction of higher-order aberrations with intraocular lenses may become standard practice. Retinal image quality in pseudophakic eyes is limited by the wavefront aberrations of the cornea and the intraocular lens. The Tecnis Z9000 is the first commercially available intraocular lens designed to account for the wavefront aberrations of the cornea, specifically spherical aberration. Clinical findings with the Tecnis Z9000 intraocular lens show improved contrast sensitivity at low and mid spatial frequencies. However, if the lens decenters or tilts modestly, higher-order aberrations are created, and the lens may underperform relative to standard intraocular lenses. At present, one firm is developing an intraocular lens that may be modified in vivo with near ultraviolet energy. Such a technology offers tremendous potential for a fully customized intraocular lens. Wavefront-customized intraocular lenses offer the promise of near perfect retinal image quality, such that only diffraction, chromatic aberration, retinal sampling and neural factors will limit vision in pseudophakic eyes.

Image quality in pseudophakic eyes with two different types of intraocular lenses ranging in the degree of high myopia

The image quality of pseudophakic eyes with intraocular lenses in high myopia was studied by applying geometric and wave optics. Two types of intraocular lenses (IOL) were compared—one that was meniscus shaped and the other either planoconcave or planoconvex [bending factor (X)511]. A geometric study of image quality was used to analyze the transverse spherical aberration (TA) and the chromatic aberration (chromatic difference of the blur circles, CDBC). The loss of image quality and visual acuity increases as the TA and CDBC increase. The polychromatic modulation transfer function (MTF) was obtained using the point-spread function (PSF), taking into account spherical aberration and defocus coefficients. Finally, for chromatic and spherical aberrations and polychromatic MTF, the type of IOL that would best improve image quality for a given patient can be established.

Image quality in pseudophakic eyes with two different types of intraocular lenses ranging in the degree of high myopia

The image quality of pseudophakic eyes with intraocular lenses in high myopia was studied by applying geometric and wave optics. Two types of intraocular lenses (IOL) were compared—one that was meniscus shaped and the other either planoconcave or planoconvex [bending factor (X)511]. A geometric study of image quality was used to analyze the transverse spherical aberration (TA) and the chromatic aberration (chromatic difference of the blur circles, CDBC). The loss of image quality and visual acuity increases as the TA and CDBC increase. The polychromatic modulation transfer function (MTF) was obtained using the point-spread function (PSF), taking into account spherical aberration and defocus coefficients. Finally, for chromatic and spherical aberrations and polychromatic MTF, the type of IOL that would best improve image quality for a given patient can be established.