Far and Near Contrast Sensitivity and Quality of Vision with Six Presbyopia Correcting Intraocular Lenses.

The objective of this prospective, randomized, double-masked study was to compare the contrast sensitivity and quality of vision of patients bilaterally implanted with the following six different presbyopia correcting intraocular lenses (IOLs): SV25T0 (n = 19), ATLISA 809M (n = 18), ATLISA TRI 839MP (n = 19), ZKB00 (n = 20), ZLB00 (n = 20) and Symfony ZXR00 (n = 20). For comparison purposes, 36 patients were implanted with a monofocal lens (ZA9003). Contrast sensitivity was assessed binocularly at distance under photopic, mesopic and mesopic plus glare conditions, and at near under photopic conditions. Quality of vision was explored in terms of photic phenomena and spectacle independence. Overall, the monofocal lens offered better contrast sensitivity, under all illumination conditions, and less occurrence and intensity of photic phenomena. Amongst the multifocal IOL (MIOL) designs, the extended depth of focus Symfony ZXR00 provided better contrast sensitivity than the other MIOLs, particularly at intermediate and high spatial frequencies. Up to 40% and 50% of patients implanted with MIOLs reported glare and halos, respectively. The SV25T0 resulted in less occurrence and intensity of halos. The evaluation of photic phenomena and contrast sensitivity under different illumination conditions may reflect real-life, visually challenging situations, and thus provide insightful information to assist ophthalmic surgeons when selecting the best intraocular lens for their patients.

Visual acuity and defocus curves with six multifocal intraocular lenses.

PURPOSE: The purpose of this prospective, randomized, double-masked, study was to compare the visual performance of patients after bilateral implantation of six different IOLs. METHODS: The following IOLs were used in the study: SV25T0 (n = 19), ATLISA 809M (n = 18), ATLISA Tri 839MP (n = 19), ZKB00 (n = 20), ZLB00 (n = 20) and Symfony ZXR00 (n = 20). Visual performance was assessed by the monocular distance-corrected visual acuity at 4 m (CDVA), distance-corrected intermediate visual acuity (DCIVA) at 60 cm and distance-corrected near visual acuity (DCNVA) at 40 cm. Binocular defocus curves were obtained for a range of defocus from + 1.50 D to - 4.50 D, in 0.50 D steps. Quality of life was assessed with the VF-14 questionnaire. RESULTS: CDVA was better with the Symfony ZXR00 than with the SV25T0 (p = 0.032), ATLISA Tri 839MP (p = 0.032) and ATLISA 809M (p = 0.018). The Symfony ZXR00 offered the best DCIVA, followed by the ZKB00. The best and worst DCNVA results corresponded to the ZLB00, and the SV25T0 and Symfony ZXR00, respectively. Defocus curves at distance were good in all groups, although the Symfony had a wider range of clear vision (- 1.50 D to + 0.50 D), with no decay. For intermediate vision, only the Symfony obtained sharp visual acuity. The ATLISA 809M, ATLISA Tri 839MP and ZLB00 were superior at near distance. CONCLUSIONS: The extended depth of focus of the Symfony ZXR00 offers a superior range of clear vision at far and intermediate distances than other multifocal designs, with worse results at near distance. Visual outcomes reflect the particular optical, geometrical and power distribution characteristics of each IOL.

Visual acuity and image quality in 5 diffractive intraocular lenses.

PURPOSE: To compare objective image quality at distant, intermediate, and near foci with the corresponding visual acuity (VA) in patients symmetrically implanted with 5 different diffractive multifocal intraocular lenses (IOLs) (ReSTOR SV25T0, Tecnis ZKB00, Tecnis ZLB00, AT LISA 809, and AT LISA Tri 839MP) and a monofocal lens (Tecnis ZA9003) 3 months after cataract intervention. METHODS: Objective image quality, measured as the area under the modulation transfer function curve (AMTF), was tested in vitro in an eye model. In addition, corrected distance visual acuity and distance-corrected intermediate and near visual acuities (DCIVA and DCNVA) were assessed in a group of 79 patients, randomly implanted with one of the lenses. RESULTS: Image quality and VA at the distant focus was good for all lens designs, but was similarly compromised at the intermediate focus, where the best DCIVA corresponded to the low add ZKB00. At the near focus, the monofocal lens and the distance dominant SV25T0 had the worst AMTF values, with the ZLB00 presenting the best DCNVA. The relationship between AMTF and VA was found not to be linear, with VA being similarly good for AMTF values over a certain threshold. CONCLUSIONS: Visual acuity of pseudophakic patients reflected the optical quality of the specific IOL design within a certain range of measurements, beyond which maximum VA is limited by other ocular, optical, and neuropsychophysical factors.

Halo and Through-Focus Performance of Four Diffractive Multifocal Intraocular Lenses.

PURPOSE: To compare, as a function of pupil size, the through-focus performance and halo features of four diffractive intraocular lenses (IOLs). METHODS: Three diffractive bifocal IOLs (ReSTOR +2.5 D SV25T0, Tecnis +2.75 D ZKB00, and AT LISA +3.75 D 809M) and a diffractive trifocal IOL (AT LISA tri +3.33 D, +1.66 D 839MP) were tested in vitro in a modified International Organization for Standardization eye model. The modulation transfer function (MTF) at the IOLs' foci was obtained with pupils ranging from 2.0 to 5.0 mm. Through-focus MTF curves (at 50 cycles/mm) were compared among all the IOLs. The halo formation and characteristics were obtained from image analysis. RESULTS: The multifocal IOLs studied in this work showed, at their foci, secondary out-of-focus images, which originate halos and whose characteristics depend on the lens design and pupil size. The smallest halo occurred for the distance focus of the SV25T0. The distance and near foci of the SV25T0 yielded, respectively, the best and lowest optical quality among the studied IOLs. The distance focus of the ZKB00, AT LISA, and AT LISA tri were of similar quality, but the near focus of the ZKB00 outperformed the near foci of the rest of the IOLs. The IOLs' optical performance gradually deteriorates as pupil increases. CONCLUSIONS: Differences in the design of the diffractive IOLs translate into differences in optical quality at their foci, through-focus performance, and halo features, which can offer further information to surgeons when selecting which IOL to implant.

Stereo-acuity in patients implanted with multifocal intraocular lenses: is the choice of stereotest relevant?

PURPOSE: A randomized and double-blinded study design was implemented to assess the stereo-acuity in patients symmetrically implanted with four types of multifocal intraocular lenses (MIOLs), compared to a monofocal lens (control group). In addition, the influence of the type of test employed for the evaluation of stereo-acuity was explored. MATERIALS AND METHODS: Six months after cataract intervention, stereo-acuity was measured with the Titmus and TNO stereotests in 143 patients implanted with one of the following MIOL lens types: hybrid spherical SN60D3, hybrid aspheric SN6AD1, diffractive aspheric ZMA00 and refractive spherical NXG1. A control group implanted with the monofocal aspheric ZA9003 (in which stereo-acuity was measured with a near addition) was also included in the study. RESULTS: Statistically significant better stereo-acuity was found in the monofocal group with both stereotests (except for the SN60D3 group with the Titmus test) (all p < 0.001). No significant differences in stereo-acuity between MIOLs were found using the Titmus test. However, with the TNO, patients implanted with hybrid diffractive MIOLs exhibited statistically significant worse stereo-acuity than those with the refractive design (SN60D3, p < 0.001; SN6AD1, p = 0.006). CONCLUSIONS: Patients implanted with MIOLs have worse stereo-acuity than those implanted with monofocal IOLs due to the decrease in retinal image contrast originating in the simultaneous presence of two images. A wavelength-based stereotest such as the TNO induces large differences in image contrast between fellow eyes implanted with diffractive-based MIOLs, which may result in an underestimation of the real stereo-acuity of the patient.

Comparison of far and near contrast sensitivity in patients symmetrically implanted with multifocal and monofocal IOLs.

PURPOSE: A prospective, randomized, double-masked, clinical trial was designed to evaluate distance and near contrast sensitivity (CS) in patients symmetrically, and randomly, implanted with 4 different multifocal intraocular lens (MIOL) designs (ReSTOR SN6AD1, ReSTOR SN60D3, ReZoom NXG, and Tecnis ZMA00) and a monofocal control group (Tecnis ZA9003), 6 months after cataract intervention. METHODS: Photopic, mesopic, and mesopic with glare distance CS, as well as photopic near CS, was evaluated with the CSV-1000 CS test and the Vistech VCTS 6000 system, respectively, in a group of 180 patients attending the ophthalmology department of Sant Pau Hospital, Barcelona, for cataract intervention and lens implantation. RESULTS: Statistically and clinically significant differences were found between the monofocal and multifocal lens groups at all spatial frequencies and illumination conditions, both during distance and near CS evaluation (all p<0.05), with the monofocal lens offering the best performance in all cases. Contrast sensitivity was similarly compromised in all MIOL models at distance, although MIOLs with diffractive optics and aspheric profiles showed a non-statistically significant trend to perform better in mesopic conditions. Near CS was lower for refractive, distance dominant lens designs, particularly at medium to high spatial frequencies. CONCLUSIONS: The present results, which reflect intraocular lens (IOL) characteristics in optics, profile, and add power, may contribute to help surgeons decide on the type of IOL most suitable for each patient by taking into consideration the individual needs for critical distance and near vision, both in terms of visual acuity and contrast sensitivity.

Visual acuity, contrast sensitivity, subjective quality of vision, and quality of life with 4 different multifocal IOLs.

PURPOSE: This prospective, randomized, double-masked, clinical trial was designed to evaluate visual acuity, contrast sensitivity, subjective quality of vision, and quality of life in 47 patients symmetrically, and randomly, implanted with 4 different IOL designs (SN6AD1, SN60D3, ReZoom NXG1, and Tecnis ZMA00), 3 months after cataract intervention. METHODS: Binocular corrected and uncorrected distance visual acuity, binocular distance corrected (BCNVA) and uncorrected (UCNVA) near visual acuity, binocular distance corrected (BCIVA) and uncorrected (UCIVA) intermediate visual acuity, photopic, mesopic, and mesopic with glare contrast sensitivity, quality of vision, and quality of life were evaluated. RESULTS: Statistically and clinically significant differences were found in BCNVA and UCNVA at 33 cm between high and low add power IOLs, while diffractive SN6AD1 lenses achieved better UCNVA at 40 cm than refractive ReZoom IOLs. Asphericity and low add power were found to improve BCIVA. Contrast sensitivity was similarly compromised in all IOL models, although diffractive optics and aspheric profiles performed better in mesopic conditions. All IOL types received similar overall satisfaction and quality of life scores. Whereas ReZoom patients depended on their spectacles for near tasks, intermediate vision was spectacle independent. Photic phenomena were present in all IOLs, albeit more frequent in ReZoom IOLs. CONCLUSIONS: The present results, which reflect IOL characteristics in optics, profile, and add power, may contribute to help surgeons decide on the type of IOL most suitable for each patient, especially those with high visual demands at near and intermediate distances.

Central thickness of hydrogel contact lenses as a predictor of success when fitting patients with tear deficiency.

A randomized, double masked, study was designed in order to investigate the relationship between the central thickness of hydrogel contact lenses and the overall comfort of patients with tear deficiency. To allow for statistical analysis, a thin lens was fitted in one eye and a thicker lens of the same characteristics in the contralateral eye. Subjects were asked to wear the lenses for 30 days on a normal daily wear basis and to graduate several factors such as comfort, dryness sensation, redness, photophobia, tearing, quality of vision and others. The results indicate that thicker lenses were preferred in terms of comfort, dryness sensation, photophobia and handling whereas thinner lenses were considered to give a better quality of vision. As a whole, thicker lenses were better tolerated by the patient. Central thickness was found to be of significant relevance when choosing a contact lens, especially when the tear film is deficient.