Evaluation Of Contrast Sensitivity Research Articles

Features of contrast sensitivity in patients with age-related cataracts

аge-related cataracts are a common ophthalmological condition characterised by clouding of the lens of the eye. This leads to reduced visual acuity, blurred images, and impaired colour perception. To assess the need for cataract surgery, it is important to evaluate contrast sensitivity, which shows a person's ability to distinguish small details that differ in brightness. The development of accurate and effective methods for the diagnosis and treatment of cataracts is an urgent scientific and practical problem. The aim of the study is to determine the diagnostic value of contrast sensitivity in patients with age-related cataracts by comparing two methods of its study. The study was conducted at the Department of Ophthalmology of the Bogomolets National Medical University on the basis of St. Michael's Clinical Hospital in Kyiv and the Medical Ophthalmological Centre ‘Zir 100%’. The study included 100 patients (100 eyes) aged 45 to 75 years diagnosed with age-related cataracts and undergoing phacoemulsification surgery with IOL implantation. The study involved 55 women and 45 men. Patients were divided into 2 groups: Group 1 - 50 patients (50 eyes) who underwent contrast sensitivity measurement using the Pelli-Robson table, Group 2 - 50 patients (50 eyes) who underwent Clinic CSF Contrast Sensitivity test. To participate in the study, all participants had to sign an informed consent. Measurements were performed 1 day before surgery and 7 days and 1 month after surgery. According to the results of the study, the comparison of contrast sensitivity between men and women did not reveal a statistically significant difference when using both methods (p=0.5). This indicates that gender is not a determining factor in the change in contrast sensitivity within the study sample. Regardless of the method of measurement, the average values of contrast sensitivity in men and women are similar, which confirms the absence of sex dependence in the functional results of the visual system by this parameter. The analysis of the results of the two methods of measuring contrast sensitivity showed that the Clinic CSF Contrast Sensitivity test demonstrates statistically higher results compared to the Pelli-Robson table (p value < 0.05). This may be due to the more accurate and sensitive measurement methods used in digital devices, which can better reflect subtle changes in contrast sensitivity. Therefore, the Clinic CSF Contrast Sensitivity test may provide a more sensitive assessment of contrast sensitivity, making it a more effective tool in clinical practice for assessing functional vision.

Reduced contrast sensitivity function and outer retina thickness in convalescent Vogt-Koyanagi-Harada disease

BackgroundTo evaluate contrast sensitivity function (CSF) in convalescent Vogt-Koyanagi-Harada (VKH) disease and investigate the relationship between CSF and chorioretinal thickness in VKH patients with and without sunset glow fundus (SGF).MethodsThis is a cross-sectional study. Seventy-six eyes of VKH patients and 56 eyes of normal controls were evaluated. Patients were divided into SGF and non-SGF groups. The best-corrected visual acuity (BCVA) of all the participants was ≤0.0 logMAR. Their CSF and macular chorioretinal thickness were measured with quantitative CSF (qCSF) and Optical Coherence Tomography (OCT) and compared using repeated measures analysis of variance at the group level. Relationships between CSF and macular chorioretinal thickness were evaluated using generalized estimating equations.ResultsThe CSF was significantly impaired in the SGF group compared to that in the control group (p = 0.001), especially at medium and high spatial frequencies. No significant CSF difference was found between the non-SGF group and control group, nor between the SGF and non-SGF groups. Compared to the controls, outer retinal thickness (ORT) in both VKH subgroups was significantly reduced (P < 0.001 or 0.005, respectively), although their outer nuclear layer thickness (ONLT) and choroidal thickness (CT) were not significantly different (both P = 1.000, P = 0.829 or 0.112, respectively). We found no significant correlation between CSF metrics and outer retinal thickness.ConclusionsDespite good recovery of visual acuity, reduced CSF and outer retina thickness were found in convalescent VKH patients. CSF may be an important and sensitive metric to evaluate functional vision in VKH disease.

Evaluation of Long-term Rotational Stability and Functional Performance of Two Toric Multifocal IOL Models Beyond 5 Years.

To assess visual outcomes and stability of lens alignment more than 3 years after implanting either the AT Lisa Tri Toric (Carl Zeiss Meditec) or the Acrysof IQ Restor Toric (Alcon Laboratories, Inc) intraocular lens (IOL). Patients who had received either the AT Lisa Tri Toric or the Acrysof IQ Restor Toric IOL were included in the study. The average follow-up period was 5.4 years for the AT Lisa Tri Toric group and 7.9 years for the Acrysof IQ Restor group. The examinations covered included: subjective refraction, monocular and binocular corrected and uncorrected visual acuity at far (4 m), intermediate (75 cm), and near (40 cm) distances, binocular best-corrected defocus curve analysis (4 m), contrast sensitivity evaluation, assessment of IOL axial position, and presence of positive dysphotopsia. A total of 42 eyes were evaluated. Both groups exhibited good long-term lens axial stability. The AT Lisa Tri Toric group had a mean misalignment of 4.8 ± 3.2° from the preoperatively determined axis, whereas the Acrysof IQ Restor Toric group had an average misalignment of 5.4 ± 4.5° (no statistically significant difference, P = .578). Mean achieved spherical equivalent was -0.19 ± 0.36 diopters (D) for the AT Lisa Tri Toric group and 0.15 ± 0.39 D for the Acrysof IQ Restor Toric group. In the AT Lisa Tri Toric group, 18 eyes (72%) achieved an uncorrected distance visual acuity of 0.10 logarithm of the minimum angle of resolution (20/25 Snellen) or better, compared to 15 eyes (88%) in the Acrysof IQ Restor Toric group. Overall, 21 eyes (84%) in the AT Lisa Tri Toric group and 14 eyes (83%) in the Acrysof IQ Restor Toric group achieved a postoperative spherical equivalent refraction between -0.50 and +0.50 D. Both the AT Lisa Tri Toric and the Acrysof IQ Restor Toric IOLs showed good long-term stability and functional outcomes. They proved to be effective options for restoring vision at far, intermediate, and near distances, providing a viable solution for presbyopia correction even several years after implantation. [J Refract Surg. 2024;40(11):e845-e853.].

Clinical Outcomes after Implantation of a Novel Binocular Complementary Extended Depth-of-Focus Intraocular Lens Compared to Bilateral Low Near-Add Multifocal Intraocular Lenses

Introduction: Nowadays, patients expect to be less spectacle dependent at all distances after cataract surgery. However, all intraocular lens (IOL) models that currently offer this function can also have negative visual effects. Aim of this study was therefore to compare the visual function performance of a novel and a conventional IOL solution for multifocality. Methods: Patients scheduled for bilateral cataract surgery were randomized to receive one of two different IOL combinations: either a binocular complementary extended depth-of-focus IOL set or a low near-add MIOL. Patients had visual acuity (VA) assessment at distance, intermediate, and near as well as evaluation of contrast sensitivity, halometry, and reading performance. Results: In total, 56 eyes of 28 patients were enrolled. At 6 months, there were no statistically significant differences in binocular VA between the ARTIS SYMBIOSE and the AT LARA. Contrast sensitivity, measured binocularly, at 1.5 cycles per degree under photopic conditions without glare was 1.54 logCS with the ARTIS SYMBIOSE and 1.43 logCS with the AT LARA (p = 0.046), under mesopic conditions with glare at 1.5 and 3 cycles per degree 1.31 logCS and 1.28 logCS with the ARTIS SYMBIOSE, respectively, compared to 0.58 logCS and 0.51 logCS with the AT LARA (p = 0.002; p = 0.006). Binocular halos and reading performance between both groups were similar. Conclusion: There were no significant differences between both groups in VA at different distances, reading ability, or halometry. The contrast sensitivity at low spatial frequencies was better in the ARTIS SYMBIOSE group under photopic conditions without glare as well as mesopic conditions with glare, which could potentially improve quality of vision with these IOLs, especially under mesopic conditions.

Evaluation of contrast sensitivity in patients with congenital red-green color vision deficiency.

To evaluate mesopic and photopic contrast sensitivity in patients with congenital red-green color vision deficiency regarding with and without glare conditions and to compare these findings with age- and gender-matched healthy controls with normal color vision. Patients with congenital red-green color vision deficiency and age- and gender-matched healthy controls were included in this cross-sectional comparative study. Contrast sensitivity measurements were taken from all subjects in 4 different conditions; binocular mesopic-without glare, mesopic-with glare, photopic-without glare, photopic-with glare, and the results were compared. Twenty one patients with color vision deficiency (13 deuteranopic, 8 protanopic) and 22 age- and gender-matched healthy controls were included in the study. The mean age was 35.2 ± 13.5years in the protan group, 30.6 ± 7.7years in the deutan group, 32.0 ± 8.8years in the control group, and there was no significant difference in age between the groups (P > 0.05). The mean mesopic and photopic contrast sensitivity values of the groups at all spatial frequencies (1.5, 3, 6, 12, 18cpd) were not statistically significant when evaluated by the multifactor repeated measures test of ANOVA to evaluate the effect of light conditions (with and without glare) (P > .05). Mesopic and photopic contrast sensitivity values of patients with congenital red-green color vision deficiency were similar to healthy controls regarding with and without glare conditions.

Evaluation of contrast sensitivity in visually impaired individuals using K-CS test. A novel smartphone-based contrast sensitivity test-Design and validation.

To describe the development and investigate the accuracy of a novel smartphone-based Contrast Sensitivity (CS) application, the K-CS test. A total of 67 visually impaired and 50 normal participants were examined monocularly using the novel digital K-CS test and the Pelli-Robson (PR) chart. The K-CS test examines letter contrast sensitivity in logarithmic units, using eight levels of contrast from logCS = ~0,1 to logCS = ~2,1 at two spatial frequencies of 1.5 and 3 cycles per degree (cpd). The K-CS test was compared to the gold standard, PR test and intra-session test repeatability was also examined. The K-CS test in normally sighted was found to agree well with the PR, providing comparable mean scores in logCS (±SD) (K-CS = 1.908 ± 0.06 versus PR = 1.93 ± 0.05) at 1.5 cpd and mean (± SD) logCS at 3 cpd (K-CS = 1.83 ± 0.13 versus PR = 1.86 ± 0.07). The mean best corrected visual acuity of visually impaired participants was 0.67 LogMAR (SD = 0.21) and the K-CS was also found to agree well with the Pelli-Robson in this group, with an equivalent mean (±SD) logCS at 1.5 cpd: (K-CS = 1.19 ± 0.27, PR = 1.15 ± 0.31), 3 cpd: K-CS = 1.01 ± 0.33, PR = 0.94 ± 0.34. Regarding the intra-session test repeatability, both the K-CS test and the PR test showed good repeatability in terms of the 95% limits of agreement (LoA): K-CS = ±0.112 at 1.5 cpd and ±0.133 at 3 cpd, PR = ±0.143 at 1.5 cpd and ±0.183 in 3 cpd in visually impaired individuals. The K-CS test provides a quick assessment of the CS both in normally sighted and visually impaired individuals. The K-CS could serve as an alternative tool to assess contrast sensitivity function using a smartphone and provides results that agree well with the commonly used PR test.

One-year outcomes of resveratrol supplement with aflibercept versus aflibercept monotherapy in wet age-related macular degeneration.

To determine the one-year outcomes of resveratrol oral supplement in patients suffering from wet age-related macular degeneration (AMD). Fifty naïve and previously untreated patients suffering from wet AMD, were randomly assigned in two subgroups of 25 patients each. All the participants were treated with 3 monthly intravitreal injections of 2.0 mg aflibercept (IAIs) followed by injections "according to need", while in one group the patients also received daily two tablets of resveratrol oral supplement. Prior to treatment initiation, a complete ophthalmological examination, including best corrected visual acuity (BCVA) and contrast sensitivity evaluation, optical coherence tomography (OCT) scans, fundus autofluorescence (FAF), fluorescein angiography, indocyanine green angiography, and OCT angiography (OCTA), was performed to every participant, while all of them completed the Hospital Anxiety and Depression Scale (HADS) questionnaire, in order to assess their quality of life (QoL) status. The patients were assessed monthly for 1y with FAF, and OCT or OCTA; the main endpoints were the number IAIs, the changes in BCVA, in contrast sensitivity, and in patients' QoL status. No significant differences were present between the groups regarding the baseline demographic and clinical data. Over the 12-month period, a similar number of IAIs was applied in both groups (4.52±1.00 vs 4.28±0.90, P=0.38), while the rest of the clinical data also did not differ significantly after the completion of the study period. However, for HADS Depression (11.88±2.51 vs 8.28±1.54, P<0.001) and HADS Anxiety (11.92±2.52 vs 7.76±1.51, P<0.001) questionnaires values, the score was significantly better in patients who received resveratrol supplements. Moreover, a statistically significant difference was detected in the mean change from baseline values of contrast sensitivity (0.17±0.19 vs 0.35±0.24, P=0.005), HADS Depression (0.08±1.38 vs -3.88±1.48, P<0.001), and HADS Anxiety (0.36±1.98 vs -5.12±2.70, P<0.001) scores, in favour of the patients treated with resveratrol supplements. The resveratrol oral supplement is a complementary treatment in cases of wet AMD, highlighting its effectiveness in improving patients' QoL status.

Digital contrast sensitivity chart with varying visual acuity: Development and validation.

Contrast sensitivity (CS) evaluation is very much necessary for the diagnosis and management of eye conditions. Several disadvantages seen in the traditionally used Pelli-Robson (PR) chart persuaded us to develop a novel digital device for the evaluation of CS at various levels of visual acuity (VA) for early detection of deteriorating vision. The new chart was constructed on the Debian software. Letters were constructed at each level of VA from 6/60 to 6/6 with a contrast of 0-2.25 logCS. The newly constructed chart was validated against the PR chart. The data were analyzed on the SPSS software version 23. The Pearson's correlation test was used to find out the correlation between the digital CS chart (DCSC) and PR charts. On successful construction of a DCSC with varying VA, 56 participants were examined with a mean age of 20.43 ± 1.44 years. The mean CS with PR was 1.84 ± 0.13 logCS, whereas DCSC was 2.09 ± 0.14 logCS. The correlation between the two charts was moderate having r = 0.489 with P = 0 (confidence interval 95%). A newly developed CS chart is efficient in examining the CS in clinical practice and has good repeatability; it may help in the early detection and monitoring of ocular diseases.

Correlation between Visual Acuity, Contrast Sensitivity and Depth of Vision before and after Partial Time Occlusion Therapy in Strabismic and Anisometropic Amblyopes

Background Amblyopia is known as the visual developmental disorder that follows selective disruption of the visual input to one eye early in life. It is considered the second most common cause of decreased visual acuity in both children and adults affecting greatly both economic and social life. It affects most of the visual parameters, so great efforts are carried out in developing effective methods controlling different deficits in amblyopia, being a great concern for all the society. However, monocular occlusion therapy remains the easiest and most popular way despite that there are many doubts in its reliability in controlling visual abnormalities other than acuity. Purpose To compare the different performance of anisometropic and strabismic eyes with moderate amblyopia, using partial occlusion therapy regarding visual acuity, contrast sensitivity and depth of vision. Methods Forty-nine children between 7 and 12 years old suffering from moderate amblyopia were classified into two groups: 25 anisometropic amblyopes and 24 strabismic ones. Two hour occlusion regimen with near activity was conducted by patients, assured by parents monitoring. Evaluation of visual acuity, contrast sensitivity and stereoacuity was conducted at each visit throughout the treatment regimen which was continued for 6 months on monthly follow up basis. Results Children in both groups improved significantly in visual acuity. There was a considerable difference among the distribution of improvement within each group where 9% of strabismic amblyopes achieved full visual recovery as compared to 40% in the anisometropic group, and 62.5% had residual amblyopia as compared to 36% in the anisometropic one, in spite of no significant difference of average improvement between groups (&amp;lt;0.0001). Only 42% of the strabismic amblyopes improved in stereoacuity as compared to 88% of the anisometropic ones, however, the difference in mean improvement was not significant between the two groups. Conclusion Children with moderate anisometropic or strabismic amblyopia 7-12 years old, can get considerable benefits from part time occlusion therapy in different visual aspects. The anisometropic amblyopes have better contrast sensitivity improvement and more reliable expectations of recovery being largely dependent on the initial visual acuity.

Assessing low vision care and the utilisation of optical low vision aids among patients with visual impairment in Taiwan.

The aim of this study was to examine the quality of assessment and the utilisation of optical low vision aids (OLVAs) among people with visual impairment (VI) in Taiwan. The study included 577 participants between 4 and 100 years of age (314 males and 263 females). All participants had been certified by the Ministry of the Interior of Taiwan, indicating that they had undergone a thorough and comprehensive low vision assessment, including evaluation of visual acuity (VA), contrast sensitivity, colour vision, visual fields and glare disability. Furthermore, all participants who consented to refraction had received prescriptions for OLVAs. All participants were prescribed one or more OLVAs such as eyeglasses, tinted lenses, magnifiers, closed-circuit television magnifiers, telescopes, or screen magnifiers. Among the 577 individuals, 515 received correction for refractive errors, providing the best-corrected VA (BCVA). The improvement in VA was significant at both distance and near, improving from 1.29 ± 0.55 to 1.01 ± 0.52 logMAR (p < 0.001) and from 1.29 ± 0.56 to 1.01 ± 0.52 logMAR (p < 0.001), respectively. Eyeglasses were the primary OLVAs chosen by 333 participants (64.7%), while 53.3%-80.3% of participants combined eyeglasses with other OLVAs to enhance their visual performance. The most commonly used and effective OLVA was eyeglasses. Skilfully utilising appropriate refractive and VA measurements is crucial for determining the most suitable and beneficial OLVA for individuals with VI.

Оценка показателей пространственной контрастной чувствительности в диагностике компьютерного зрительного синдрома у пользователей девайсами (данные пилотного исследования)

In the modern world, there is an increase in the severity of computer vision syndrome (CVS) when using digital devices. Despite numerous studies of ophthalmic symptoms of CVS, neuro-ophthalmic manifestations remain poorly understood. Evaluation of spatial contrast sensitivity (SCS) indicators can be relevant and informative in identifying functional changes in the visual system when using devices. A pilot study was conducted with the participation of 15 healthy people. The subjects were assessed the SCS in the process of habitual activity in a personal device, which was considered a visual load using the author's program «Visocontrastometry» after 15 minutes, 30 minutes, 45 minutes of use. The results were analyzed using descriptive statistics, and the nonparametric Mann – Whitney test was used to test for significance. According to the data obtained, in all time intervals, there is a decrease in SCS at the experimental stage compared with the control indicators of SCS. A statistically significant difference is observed 15 minutes after the visual load at a spatial frequency of 1.0 cycle/deg in the blue color range (p ≤ 0.05). The method for assessing the SCS has shown its adequacy for studying the neuro-ophthalmological aspects of CVS. Keywords: сomputer vision syndrome, contrast sensitivity, device

Optic Neuritis: Evaluation of Visual Acuity and Contrast Sensitivity. A Hospital Based Cross Sectional Study

Optic Neuritis: Evaluation of Visual Acuity and Contrast Sensitivity. A Hospital Based Cross Sectional Study

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.

Spectral-sensitive proton radiography of thin samples with the pixel detector Timepix3

We evaluate a high-resolution contrast-enhanced method for energy-sensitive radiography of thin samples with low-energy protons at the light-ion Tandetron accelerator of the NPI-CAS in Rez near Prague. We make use of the high-sensitivity of the hybrid semiconductor pixel detectors Timepix enabled by integrated per-pixel signal processing electronics. For this work we use the Timepix3 ASIC chip equipped with a 500 µm Si sensor operated with the fast data rate AdvaPix readout electronics interface. Measurements are performed in air with a 2.9 MeV proton microbeam on thin samples (<100 µm thick). As referential and testing sample we use a set of aluminum foils stacked into a closely packed assembly of varying layers of well-defined thickness. This and other samples were imaged and placed in front of the detector in transmission geometry. Radiographies were collected with focused beam (few mm size) and a microbeam (few µm size). The imaging principle is based on high-resolution spectrometry of single transmitted particles. Contrast is obtained by registration of small differences in the deposited energy of the proton after passing through the sample. This can be measured in wide-range by detailed spectral-tracking analysis of the pixelated clusters in the pixel detector. We examine and evaluate various cluster-track parameters sensitive for imaging contrast such as deposited energy, cluster area (number of pixels) and cluster height (maximum energy value of the pixels in the cluster). The position of interaction in the detector is registered in sub-pixel resolution down to few µm scale for the particles and geometry used. Radiographies are reconstructed based on these individual parameters imaged in image bins of adjustable size (few µm up to few tens of µm). The technique developed with different cluster parameters is presented together with evaluation of image contrast sensitivity on various types of samples and beam energies.

Evaluation of contrast sensitivity in non-high-risk proliferative diabetic retinopathy treated with panretinal photocoagulation with and without intravitreal injections of ranibizumab.

To evaluate contrast sensitivity in non-high-risk, treatment-naïve proliferative diabetic retinopathy patients treated with panretinal photocoagulation and intravitreal injections of ranibizumab) versus panretinal photocoagulation alone. Sixty eyes of 30 patients with bilateral proliferative diabetic retinopathy were randomized into two groups: one received panretinal photocoagulation and ranibizumab injections (study group), while the other received panretinal photocoagulation alone (control group). All eyes were treated with panretinal photocoagulation in three sessions according to the Early Treatment Diabetic Retinopathy Study guidelines. Contrast sensitivity measurements were performed under photopic conditions (85 cd/m2) with the Visual Contrast Test Sensitivity 6500 chart, allowing for the evaluation of five spatial frequencies with sine wave grating charts: 1.5, 3.0, 6.0, 12.0, and 18.0 cycles per degree (cpd). Outcomes were measured in contrast sensitivity threshold scores among and within groups, from baseline to 1, 3, and 6 months. Fifty-eight eyes (28 in the study group and 30 in the control group) reached the study endpoint. A comparative analysis of changes in contrast sensitivity between the groups showed significant differences mainly in low frequencies as follows: at month 1 in 1.5 cpd (p=0.001) and 3.0 cpd (p=0.04); at month 3 in 1.5 cpd (p=0.016), and at month 6 in 1.5 cpd (p=0.001) and 3.0 cpd (p=0.026) in favor of the study group. In eyes of patients with non-high-risk proliferative diabetic retinopathy, panretinal photocoagulation treatment with ranibizumab appears to cause less damage to contrast sensitivity compared with panretinal photocoagulation treatment alone. Thus, our evaluation of contrast sensitivity may support the use of ranabizumab as an adjuvant to panretinal photocoagulation for the treatment of proliferative diabetic retinopathy.

Contrast Sensitivity Measurement Tests and Methods

Contrast is a measure of the amount of lightness or darkness an object has in relationship to its background. Usually, it is described as Contrast Sensitivity (CS), which actually is the inverse of the contrast threshold. More often than not, stimulus set includes grating patterns of various sizes that are presented in a stationary manner or are dynamically presented by reversing the contrast at different rates.&#x0D; A variety of tests were developed, in order to asses and evaluate contrast sensitivity, in many different ways. A classical method, to check for contrast sensitivity, is the Pelli-Robson contrast sensitivity chart.&#x0D; The Bailey-Lovie contrast sensitivity chart is another letter chart that deals with differences in the number of letters read on the high and low contrast charts, with a main drawback, the necessity to follow the size of the letters.&#x0D; The Functional Acuity Contrast Test is designed to identify vision loss from a variety of disorders, many of which are not detected by high or low contrast Snellen Acuity tests. The MARS Letter Contrast Sensitivity Test shows good agreement with the Pelli-Robson test and possibly it may be the alternative to the Pelli-Robson chart, in clinical practice and research.

SLM-based interferometer for assessing the polychromatic neural transfer function of the eye.

A novel interferometric instrument for measuring neural transfer function (NTF) of the eye is presented. The device is based on a liquid-crystal-on-silicon spatial light modulator (SLM), which is used to create two laterally separated wavefronts in the pupil plane of the eye that interfere on the retina. The phase mask on the SLM, consisting of two diffraction gratings mixed in a checkerboard pattern and acting as a shearing interferometer, allows independent control of spatial frequency, orientation, and contrast of the fringes, as well as the field of view in a wide polychromatic spectrum. Coupled with a supercontinuum source, the system is able to produce achromatic fringes on the retina. The instrument was successfully tested in six normal subjects in four light conditions: polychromatic light and monochromatic blue, green and red light respectively (central wavelengths - 450, 550 and 650 nm). On average, the NTF in polychromatic light was approximately 20% higher than for green and red light, although not statistically significant due to high intersubject variability. Due to all-digital control of the interference fringes, the device is optically simple and virtually unsusceptible to vibrations, allowing its use in a non-laboratory environment. The study also contributes to color vision research, allowing to evaluate contrast sensitivity function without monochromatic or chromatic aberrations.

Standard Results and Contrast Sensitivity Reestablishment after Implantation of a Trifocal Intraocular Lens

ABSTRACT Purpose/Aim To assess, following the standards, the results of safety, efficacy and predictability for a trifocal intraocular lens and to evaluate contrast sensitivity and visual acuity defocus curve. Materials and Methods Fifty subjects operated on cataract surgery or refractive lens exchange with a trifocal intraocular lens have been recruited for the study. The monocular uncorrected visual acuity (VA) at far, intermediate (67 cm) and near (40 cm) distances in addition to corrected VA at far and near distances was evaluated at 1 week, 1 month and 3 months after surgery. Postoperative refraction, binocular contrast sensitivity function (CSF) and binocular defocus curves were also collected at the 3-month follow-up visit. Results Mean uncorrected VA was 0.10, 0.07 and 0.05 logMAR at far, intermediate and near distances. Corrected distance VA at far and near distances was 0.04 and 0.02 logMAR. Ninety percent and 100% achieved a spherical equivalent in ±0.50 D and ±1.00 D, respectively. CSF was above normal range for 12 and 18 cycles per degree (cpd) in all the conditions, inside the normal range in 1.5, 3 and 6 cpd and only decreased below normal range for 1.5 and 3 cpd in mesopic vision without glare. Conclusions The procedure achieved a safety, efficacy and predictability similar to those reported by previous studies. The CSF was generally enhanced after the procedure in comparison to those reported in non-operated subjects above 60 years old. Previous studies might underestimate the effective distance of the intermediate and near foci.

Enhanced aspheric optic: the ideal compromise for intermediate visual acuity.

We read with interest the study by Mencucci et al. in which the visual outcome, optical quality, and patient satisfaction of the TECNIS Eyhance ICB00 IOL were analyzed and compared with those of the TECNIS ZCB00 IOL.1 The authors concluded that the Eyhance ICB00 IOL provided better uncorrected intermediate visual acuity (UIVA) and higher intermediate spectacle independence without impairment of far vision and visual quality, compared with the ZCB00 IOL.1 In general, the study is well designed. On the other hand, the article has some weaknesses. First, the depth of focus of an optical system might be influenced by appropriate modification of spherical aberration (SA).2 In a young human eye, SA is a combination of the positive SA of the cornea and the negative SA of the crystalline lens.3 The SA of the cornea is highly variable between 0.0 and +0.64 μm with an average of +0.22 to +0.33 μm, according to different authors.3,4 Patients included in the study by Mencucci et al. had a comprehensive preoperative ophthalmological examination but not evaluation of the corneal SA. Because of the relatively small sample size, there is no guarantee that the average corneal SA was the same in the 2 groups of patients. Second, the authors compared the newly developed Eyhance ICB00 IOL with the ZCB00 IOL (both with −0.27 μm SA at 6.0 mm pupil), and they found a significantly higher UIVA in the Eyhance IOL group. The aspheric IOLs with negative SA have presumably decreased depth of focus. For that reason, it would be better to compare the visual performance of the Eyhance ICB00 IOL also with an SA-free monofocal aspheric IOL, where one can expect a wider depth of focus and, theoretically, a better intermediate visual acuity (VA). Third, mesopic contrast sensitivity is a sensitive measure of visual performance of IOLs. The authors evaluated contrast sensitivity under photopic conditions at different spatial frequencies, but they did not examine it under mesopic conditions. There are data in the literature that the only difference between TECNIS ZCB00 IOL and another monofocal aspheric IOL was the better mesopic contrast sensitivity with TECNIS ZCB00 IOL.5 Fourth, the optical quality parameters were analyzed correctly with the same pupil diameter, but there were no data in the article whether the subjective VA (especially intermediate) was assessed with the same pupil size. Of course, it is technically hard to measure these data during VA testing, but different pupil sizes alone can result in different depth of focus, that is, without taking into account the type of the implanted IOL. Pupil size measurement before VA testing might partially help to solve this obvious problem. We do believe that it is possible to construct a monofocal IOL with an ideal compromise between relatively wide depth of focus and satisfactory optical quality. However, the data obtained about TECNIS Eyhance ICB00 IOL are not sufficient to declare that this type of IOL would be the ideal compromise. Further investigations are necessary.

Time course of changes in contrast sensitivity following intravitreal ranibizumab injection for branch retinal vein occlusion.

To evaluate contrast sensitivity (CS) in patients with branch retinal vein occlusion (BRVO) following intravitreal ranibizumab injection (IVR), and to investigate the relationship between CS and retinal microstructure. A retrospective, observational case series. We included 23 eyes with treatment naïve BRVO followed up for 6months after treatment. Best-corrected visual acuity (BCVA), letter contrast sensitivity (LC), and 10% low contrast visual acuity (LCVA) were measured. All tests were performed before and 1, 2, 3, 4, 5, and 6months after treatment. Based on optical coherence tomography (OCT) images, we assessed central retinal thickness (CRT), presence of serous retinal detachment (SRD), and status of the external limiting membrane (ELM) and ellipsoid zone (EZ). IVR treatment significantly improved CS (LC: P < 0.0001, LCVA: P = 0.004) as well as BCVA (P = 0.015) and CRT (P < 0.0001). LC and LCVA at 6months after treatment were significantly correlated with presence of SRD before treatment. At 6months after treatment, LCVA was significantly correlated with pre-treatment CRT (P = 0.042). In patients with good baseline BCVA, LCVA showed significant improvements (P = 0.022) although their BCVA did not change. In patients with poor improvement in BCVA, LC and LCVA also showed significant improvements (P = 0.008, P = 0.005). IVR treatment for BRVO improves both BCVA and CS. Even in patients without any improvement in visual acuity, CS does improve.