Improved Contrast Sensitivity Research Articles

Blue light–filtering and violet light–filtering hydrophobic acrylic foldable intraocular lenses: Intraindividual comparison

To compare the clinical outcomes after cataract surgery and implantation of a blue light-filtering IOL (AcrySof IQ SN60WF) or a violet light-filtering intraocular lens (IOL) (OptiBlue ZCB00V). Four surgical sites in Japan. Prospective case series. One eye of patients with bilateral cataract was randomly allocated to the blue light-filtering IOL and the fellow eye to the violet light-filtering IOL. Visual acuity and contrast sensitivity were assessed over 3months. The incidence of cyanopsia was evaluated using the neutralization method. The study enrolled 110 eyes of 55 patients. There was no significant difference in visual acuity between the two IOLs. Based on the neutralization results 1week postoperatively, 15 cases (27.8%) with the light-filtering IOL and 8 cases (14.8%) with the violent light-filtering IOL had cyanopsia; the difference reached statistical significance (P=.049). After 2weeks, the difference in the incidence of cyanopsia was not significant. Postoperative contrast sensitivity under photopic condition at 1week and 3months and contrast sensitivity under mesopic conditions at 3months were significantly better with the violet light-filtering IOL than with the blue light-filtering IOL (P<.05). The violet light-filtering IOL yielded highly satisfactory clinical outcomes, including reduction of cyanopsia and a potential improvement in contrast sensitivity. The different chromophores of the IOL and its different material and design might have contributed.

A DOUBLE-MASKED, RANDOMIZED, SHAM-CONTROLLED, SINGLE-CENTER STUDY WITH PHOTOBIOMODULATION FOR THE TREATMENT OF DRY AGE-RELATED MACULAR DEGENERATION.

The LIGHTSITE I study investigated the efficacy and safety of photobiomodulation (PBM) treatment in subjects with dry age-related macular degeneration. Thirty subjects (46 eyes) were treated with the Valeda Light Delivery System, wherein subjects underwent two series of treatments (3× per week for 3-4 weeks) over 1 year. Outcome measures included best-corrected visual acuity, contrast sensitivity, microperimetry, central drusen volume and drusen thickness, and quality of life assessments. Photobiomodulation-treated subjects showed a best-corrected visual acuity mean letter score gain of 4 letters immediately after each treatment series at Month 1 (M1) and Month 7 (M7). Approximately 50% of PBM-treated subjects showed improvement of ≥5 letters versus 13.6% in sham-treated subjects at M1. High responding subjects (≥5-letter improvement) in the PBM-treated group showed a gain of 8 letters after initial treatment (P < 0.01) and exhibited earlier stages of age-related macular degeneration disease. Statistically significant improvements in contrast sensitivity, central drusen volume, central drusen thickness, and quality of life were observed (P < 0.05). No device-related adverse events were reported. Photobiomodulation treatment statistically improved clinical and anatomical outcomes with more robust benefits observed in subjects with earlier stages of dry age-related macular degeneration. Repeated PBM treatments are necessary to maintain benefits. These pilot findings support previous reports and suggest the utility of PBM as a safe and effective therapy in subjects with dry age-related macular degeneration.

Microperimetric changes and fixation stability status after half-dose photodynamic therapy for chronic central serous chorioretinopathy.

The aim of this study was to evaluate the effect of half-dose verteporfin photodynamic therapy on central retinal sensitivity, status of fixation stability, and choroidal thickness in patients with chronic central serous chorioretinopathy. In total, 22 eyes of 22 patients with chronic central serous chorioretinopathy were enrolled, and all the eyes received indocyanine green angiography-guided half-dose verteporfin photodynamic therapy. Best-corrected visual acuity, contrast sensitivity, and retinal sensitivity in the central 10° and status of the fixation stability are assessed by MAIA microperimetry, and optical coherence tomography findings (central macular thickness and subfoveal choroidal thickness) were evaluated at baseline and 1, 3, and 6 months after the half-dose verteporfin photodynamic therapy. Subretinal fluid was completely resolved in 9 eyes at 1 month and in 17 eyes at 3 months. There was recurrence in two eyes at 6 months and five of the eyes had a persistent subretinal fluid through all the time points. Best-corrected visual acuity, contrast sensitivity, and retinal sensitivity improved significantly 6 months after half-dose verteporfin photodynamic therapy. Fixation stability did not change in either follow-up visit. Central macular thickness and subfoveal choroidal thickness decreased significantly at 6 months of the visits compared to baseline. There was not any systemic and ocular side effect after the treatment. This study shows that there is significant improvement in best-corrected visual acuity, contrast sensitivity, and retinal sensitivity after half-dose verteporfin photodynamic therapy. The status of fixation stability remained unchanged in the eyes with chronic central serous chorioretinopathy after half-dose verteporfin photodynamic therapy. Furthermore, half-dose verteporfin photodynamic therapy is also effective in decreasing central macular thickness and subfoveal choroidal thickness.

REDD1 Activates a ROS-Generating Feedback Loop in the Retina of Diabetic Mice.

PurposeThe present study was designed to evaluate the role of the stress response protein REDD1 in diabetes-induced oxidative stress and retinal pathology.MethodsWild-type and REDD1-deficient mice were administered streptozotocin to induce diabetes. Some mice received the antioxidant N-acetyl-l-cysteine (NAC). Visual function was assessed by virtual optometry. Retinas were analyzed by Western blotting. Reactive oxygen species (ROS) were assessed by 2,7-dichlorofluoroscein. Similar analyses were performed on R28 retinal cells in culture exposed to hyperglycemic conditions, NAC, and/or the exogenous ROS source hydrogen peroxide.ResultsIn the retina of diabetic mice, REDD1 expression and ROS were increased. In cells in culture, hyperglycemic conditions enhanced REDD1 expression, ROS levels, and the mitochondrial membrane potential. However, similar effects were not observed in the retina of diabetic mice or cells lacking REDD1. In the retina of diabetic mice and cells exposed to hyperglycemic conditions, NAC normalized ROS and prevented an increase in REDD1 expression. Diabetic mice receiving NAC also exhibited improved contrast sensitivity as compared to diabetic controls. Hydrogen peroxide addition to culture medium increased REDD1 expression and attenuated Akt/GSK3 phosphorylation in a REDD1-dependent manner. In REDD1-deficient cells exposed to hyperglycemic conditions, expression of a dominant negative Akt or constitutively active GSK3 increased the mitochondrial membrane potential and promoted ROS.ConclusionsThe findings provide new insight into the mechanism whereby diabetes-induced hyperglycemia causes oxidative stress and visual dysfunction. Specifically, hyperglycemia-induced REDD1 activates a ROS-generating feedback loop that includes Akt/GSK3. Thus, therapeutic approaches targeting REDD1 expression and ROS may be beneficial for preventing diabetes-induced visual dysfunction.

Transorbital alternating current stimulation modifies BOLD activity in healthy subjects and in a stroke patient with hemianopia: A 7 Tesla fMRI feasibility study

BackgroundModifying brain activity using non-invasive, low intensity transcranial electrical brain stimulation (TES) has rapidly increased during the past 20 years. Alternating current stimulation (ACS), for example, has been shown to alter brain rhythm activities and modify neuronal functioning in the visual system. Daily application of transorbital ACS to patients with optic nerve damage induces functional connectivity reorganization, and partially restores vision. While ACS is thought to mainly modify neuronal mechanisms, e.g. changes in brain oscillations that can be detected by EEG, it is still an open question, whether and how it may alter BOLD activity. ObjectiveWe evaluated whether transorbital ACS modulates BOLD activity in early visual cortex using high-resolution 7 Tesla functional magnetic resonance imaging (fMRI). MethodsIn this feasibility study transorbital ACS in the alpha range and sham ACS was applied in a random block design in five healthy subjects for 20 min at 1 mA. Brain activation in the visual areas V1, V2 and V3 were measured using 7 Tesla fMRI-based retinotopic mapping at the time points before (baseline) and after stimulation. In addition, we collected data from one hemianopic stroke patient with visual cortex damage after ten daily sessions with 25–50 min stimulation duration. ResultsIn healthy subjects transorbital ACS increased the activated cortical surface area, decreased the fMRI response amplitude and increased coherence in the visual cortex, which was most prominent in the full field task. In the patient, stimulation improved contrast sensitivity in the central visual field. BOLD amplitudes and coherence values were increased in most early visual areas in both hemispheres, with the most pronounced activation detected during eccentricity testing in retinotopic mapping. ConclusionsThis feasibility study showed that transorbital ACS modifies BOLD activity to visual stimulation, which outlasts the duration of the AC stimulation. This is in line with earlier neurophysiological findings of increased power in EEG recordings and functional connectivity reorganization in patients with impaired vision. Accordingly, the larger BOLD response area after stimulation can be explained by more coherent activation and lower variability in the activation. Alternatively, increased neuronal activity can also be taken into account. Controlled trials are needed to systematically evaluate the potential of repetitive transorbital ACS to improve visual function after visual pathway stroke and to determine the cause-effect relationship between neural and BOLD activity changes.

Exploring the Role of Telemedicine in Low Vision Rehabilitation in Patients with Heredomacular Degeneration – A Novel Concept

Background Teleophthalmology is widely used for screening and diagnosis of many eye disorders. But its role in low vision rehabilitation is unexplored. The purpose of this study was to explore the feasibility of teleophthalmology for visual rehabilitation. Methods We prospectively enrolled 15 patients (age range 12-30 years, mean 16±3.2 years) with heredomacular degeneration with reduced central vision but healthy paracentral retina. We used visual stimulation and biofeedback with video game play. After the baseline investigations, the patients were given a compact disc with the video game and were trained to play the game. Subsequently, they did 40 hours of the visual training at home which was monitored using teleophthalmology by us at our tertiary institute. We used video chat and screen sharing software to guide the patients and monitor compliance. The primary outcome was feasibility of monitoring visual training remotely and secondary outcome was improvement in visual function. Results Seven patients returned for follow up after completing the training. The visual acuity improved from 0.74±0.29 to 0.66±0.32 logMAR (p=0.043). There was significant improvement in contrast sensitivity (p=0.023) and fixation stability (p=0.018). The vision related quality of life questionnaire showed improved scores. The ease of communication, patient comfort were high. The office visits were limited to two. Conclusions Our study showed preliminary evidence of benefit of teleophthalmology in visual rehabilitation and monitoring. The reduced visits would likely promote compliance and reduce economic burden of the rehabilitatory training.

EFFICACY OF ORAL GLUTATHIONE ADDITION IN LUTEIN SUPPLEMENTATION ON CONTRAST SENSITIVITY IMPROVEMENT IN DRY AGE-RELATED MACULAR DEGENERATION: A RANDOMIZED CONTROLLED TRIAL

Objective: Age-related macular degeneration (ARMD) is the macular abnormality causing central vision loss in the elderly. One prevention for ARMD is the provision of antioxidants, such as lutein. Reduced form of glutathione (GSH) is a source of cysteine and sulfhydryl, playing a role in detoxification, transport, and metabolic processes. Both are prospected to have a synergistic effect in the prevention of ARMD. This study aimed to determine the efficacy of GSH addition in lutein supplementation to improve the contrast sensitivity of dry type ARMD patients.&#x0D; Methods: This randomized controlled trial was conducted at an eye hospital and a tertiary general hospital from April 2016 to June 2016. This study involved 22 dry ARMD patients. Subjects were randomized and divided into treatment groups with 20 mg lutein with the addition of 500 mg GSH and 20 mg lutein only, for 30 days. Contrast sensitivity measurement was performed with Lea Numbers® Low Contrast Flip Chart before and after the treatment. Contrast sensitivity was analyzed comparatively with paired t-test.&#x0D; Results: Contrast sensitivity improvement was observed in both the groups. Contrast sensitivity improvement of the group with additional GSH (3.62±1.44, p&lt;0.05) was a 3-fold of the lutein group only (1.25±0.44, p&gt;0.05). The result was statistically significant for the group treated with GSH addition.&#x0D; Conclusion: GSH addition in lutein supplementation provoked better contrast sensitivity improvement in dry ARMD patients.

Short-term effects of intravitreal bevacizumab in contrast sensitivity of patients with diabetic macular edema and optimizing glycemic control

AimsTo analyze contrast sensitivity of intravitreal bevacizumab injections with optimizing glycemic control versus optimizing glycemic control (in combination with sham injections) in eyes with Diabetic Macular Edema (DME). DesignProspective, interventional, masked, randomized controlled trial. MethodsForty-one eyes of 34 patients with type 2 diabetes mellitus and DME with glycated hemoglobin (HbA1c) < 11% received either intravitreal bevacizumab injection (Group 1) or sham injection (Group 2) at 0 and 6 weeks along with optimizing glycemic control. Mean change in best-corrected visual acuity (BCVA), contrast sensitivity (CS), optical coherence tomography (OCT)-measured by central macular thickness (CMT) were compared and correlated at baseline, 2, 6 and 12 weeks. ResultsThe study showed a mean CS improved in group 1 from 1.14 ± 0.36 logCS to 1.32 ± 0.24 logCS and also in group 2 from 1.11 ± 0.29 logCS to 1.18 ± 0.29 logCS at 12 weeks (P = 0.12). CS and CMT promptly decreased in group 1 compared to group 2 at 2 weeks (ΔCS = 0.15 ± 0.25 vs. 0.03 ± 0.15 logCS; P = 0.04; ΔCMT = 116 ± 115 vs. 17 ± 71 μm; P = 0.01). There was a mean reduction of approximately 0.5% in HbA1c levels in both groups at 12 weeks (P = 0.002). ConclusionThe use of bevacizumab in combination with optimizing glycemic control results in earlier improvement of contrast sensitivity in type 2 diabetes patients with DME. However, the optimizing glycemic control itself has shown also to be effective at 12 weeks.ClinicalTrials.gov Identifier: NCT02308644.

Ocular findings and vision status of learners with oculocutaneous albinism

Background: Oculocutaneous albinism results in defects of the visual pathway and ocular structures. Aim: To determine the ocular findings and vision status of learners with oculocutaneous albinism (OCA) as well as to establish the level of visual acuity, contrast sensitivity and reading rate improvements following optical correction. Setting: Three special education schools in KwaZulu-Natal, South Africa. Methods: A total of 81 learners with OCA participated in this study. Testing procedures included logMAR distance and near visual acuity (VA) measurements, cover tests, retinoscopy (dry), subjective refraction, tangent screen, ophthalmoscopy, contrast sensitivity and reading rate determination. Results: The majority of participants (96.3%) had wheat straw coloured hair and 95.1% had grey irides. All the learners presented with iris-transillumination and an absent foveal reflex and all but one exhibited nystagmus. Esophoria and esotropia represented 72.8% of binocular vision anomalies. Myopic astigmatism was noted in 41.4% of the learners while with the rule astigmatism was predominant (64%). Following optical correction, VA significantly improved from a range of 0.50 to 1.40 logMAR to a range of 0.5 to 1.06 logMAR for distance ( p 0.05). Conclusion: Learners with OCA exhibited various ocular and vision defects which impair visual functions. Their VA and contrast sensitivity could be significantly improved with optical correction; however, their reading rate was not improved.

Comparison of ranibizumab alone versus ranibizumab with targeted retinal laser for branch retinal vein occlusion with macular edema.

Purpose:To determine the effect of ultra-widefield fluorescein angiography (UWFFA)-guided targeted retinal photocoagulation (TRP) in branch retinal vein occlusion (BRVO) with macular edema after intravitreal Ranibizumab (RBZ).Methods:33 eyes of 32 treatment naïve patients diagnosed as BRVO with macular edema were prospectively randomized to 0.5 mg Ranibizumab only (RBZ group) (n = 17) or Ranibizumab with UWFFA-guided laser (RBZ + TRP group) (n = 16). Both groups received three injections at monthly intervals and PRN henceforth. RBZ + TRP group additionally underwent UWFFA-guided TRP of peripheral capillary nonperfusion areas 1 week post injection. Outcome measures included improvement in visual acuity, central subfoveal thickness (CST), and the number of injections required with a minimum follow-up of 9 months.Results:Both groups showed significant improvement in mean BCVA (25.7 ± 8.19 letters, P < 0.001 vs. 23.38 ± 7.56 letters, P < 0.001; in RBZ and RBZ + TRP group, respectively) and reduction in mean central subfoveal thickness (379.12 ± 242.7 μm, P < 0.001 vs. 253.75 ± 137.9 μm, P < 0.001 in RBZ and RBZ + TRP group, respectively) at 9 months. The number of injections in the RBZ group (5.76 ± 1.3) was significantly greater than RBZ + TRP (4.06 ± 0.99) (P < 0.001). Both groups had significant improvement in contrast sensitivity and mean deviation on visual fields; however, the difference between the groups was not significant (P = 0.62 and P = 0.79, respectively).Conclusion:UWFFA-guided TRP reduced the number of injections of Ranibizumab in patients having BRVO with macular edema, while maintaining similar benefits in the improvement of BCVA, central subfoveal thickness without deleterious effect on the visual field, and contrast sensitivity.

Lutein-Containing Antioxidants in Patients with Primary Open-Angle Glaucoma and Dry Type of Age-Related Macular Degeneration

Objective.To assess the dynamics of structural-functional markers in patients with combined pathology: primary open-angle glaucoma (POAG) and age-related macular degeneration (AMD) with the background of lutein-containing drugs at long-term follow-up.Patients and Methods.The period of research was from November 2016 to January 2018; A parallel prospective study of patients (88 eyes), mean age 67.81 ± 8.41 (M ± σ); 67.64 (63.14; 73.08) (Me, Q25%, Q75%) years with combined pathology POAG and AMD (AREDS I and II). Patients were divided into 2 groups, the first group — a study group received Retinorm, by 1 capsule 3 times a day during a meal for 1 year, a second control group of 17 patients (32 eyes) did not receive lutein-containing medicines during the observation period. The study group consisted of 29 patients (55 eyes). There were 7 males and 22 females among them. The control group consisted of 19 patients (33 eyes), 2 males and 17 females among them. Visual acuity, standard automatic computer perimetry, optical coherence tomography, determination of spatial contrast sensitivity was carried out in all patients at the beginning of the study and after 1 year.Results.The maximum correlated visual acuity (MCVA) according to the table ETDRS increased in the study group and decreased in the control group, 95% the confidence interval for the changes in the MCVA: 0.1813636; 1.018182; 1.927273 и –3.878788; –2.393939; –0.8477273 (optotypes), respectively (W = 499.5; p = 0,0002919). Statistically significant changes in the thickness of the layer of nerve fibers of the retina (RNFL) neither in the middle nor in the sectors was revealed, and the thickness of the retina in oval foveal zone by sector: upper, temporal and lower statistically significantly decreased in the control group, while remaining unchanged in the observation group (р &lt; 0.05). Spatial contrast sensitivity (SCS) after 1 year of use Retinorm remained at the same level in the control group, while there was a statistically significant increase in spatial contrast sensitivity in the main group, especially at high spatial frequencies is observed (р &lt; 0.05).Conclusion.The results of the study indicate a positive effect of Retinorm used for 1 year. It was reflected in the improvement visual acuity in the distance, improvement of spatial contrast sensitivity, especially at high spatial frequencies, and the preservation of structural retinal indices both in the foveal zone and peripapillary.

Clinical outcomes following trifocal diffractive intraocular lens implantation for age-related cataract in China.

PurposeThe aim of this study was to evaluate visual, refractive and patient satisfaction outcomes following implantation of a trifocal diffractive intraocular lens (IOL).Patients and methodsThis prospective, consecutive study included patients undergoing lens phacoemulsification of cataract and implantation of a trifocal diffractive IOL (AT LISA tri 839MP). Visual outcomes, including near, intermediate and distance visual acuity (VA), refractive error, contrast sensitivity, defocus curve and patient satisfaction were assessed preoperatively and postoperatively.ResultsThirty IOLs were implanted in 26 patients. Distance VA improved significantly from 0.70±0.45 to 0.08±0.11 logMAR (p<0.0001) 1 week postoperatively, and to 0.07±0.13 logMAR (p<0.0001) at 1 month and 0.05±0.10 logMAR (p<0.0001) at 3 months. Uncorrected near and intermediate VA, as well as corrected near, intermediate and distance VA, were stable and maintained during the follow-up period. Preoperative anterior chamber depth demonstrated an association with effective adjustment of postoperative spherical equivalent using a regression formula (p=0.007). No significant differences were observed for VA at defocus curves of 0 to −3 D. Contrast sensitivity at each spatial frequency improved significantly at 1 week, 1 month and 3 months under photopic and photopic with glare conditions. Under mesopic and mesopic with glare conditions, significant differences were observed postoperatively at low and medium spatial frequencies. Patients reported a high level of satisfaction and an absence of glare or halo 3 months postoperatively.ConclusionIn this study, the trifocal diffractive IOL provided excellent visual performance at all distances and improved contrast sensitivity under different conditions, resulting in high levels of patient satisfaction and spectacle independence in Chinese patients.

Contrast‐balanced binocular treatment in children with deprivation amblyopia

BackgroundChildren with deprivation amblyopia due to childhood cataract have been excluded from much of the emerging research into amblyopia treatment. An investigation was conducted to determine whether contrast‐balanced binocular treatment – a strategy currently being explored for children with anisometropic and strabismic amblyopia – may be effective in children with deprivation amblyopia.MethodsAn unmasked, case‐series design intended to assess proof of principle was employed. Eighteen children with deprivation amblyopia due to childhood cataracts (early bilateral n = 7, early unilateral n = 7, developmental n = 4), as well as 10 children with anisometropic (n = 8) or mixed anisometropic and strabismic amblyopia (n = 2) were prescribed one hour a day of treatment over a six‐week period. Supervised treatment was available. Visual acuity, contrast sensitivity, global motion perception and interocular suppression were measured pre‐ and post‐treatment.ResultsVisual acuity improvements occurred in the anisometropic/strabismic group (0.15 ± 0.05 logMAR, p = 0.014), but contrast sensitivity did not change. As a group, children with deprivation amblyopia had a smaller but statistically significant improvement in weaker eye visual acuity (0.09 ± 0.03 logMAR, p = 0.004), as well a significant improvement in weaker eye contrast sensitivity (p = 0.004). Subgroup analysis suggested that the children with early bilateral deprivation had the largest improvements, while children with early unilateral cataract did not improve. Interestingly, binocular contrast sensitivity also improved in children with early bilateral deprivation. Global motion perception improved for both subgroups with early visual deprivation, as well as children with anisometropic or mixed anisometropic/strabismic amblyopia. Interocular suppression improved for all subgroups except children with early unilateral deprivation.ConclusionThese data suggest that supervised contrast‐balanced binocular treatment should be further investigated as a treatment option for children with deprivation amblyopia. However, for children with more severe deprivation amblyopia due to early unilateral cataracts, supplementary or alternative options should also be explored.

Deletion of REDD1 Prevents Hyperglycemia-Induced Reactive Oxygen Species Accumulation and Retinal Cell Death

Apoptosis of retinal neurons is accelerated by diabetes and the onset of increased cell death occurs early in disease progression. The present study was designed to evaluate molecular defects that contribute to diabetes-induced neuroretinal apoptosis and visual dysfunction. We recently demonstrated that the stress response protein REDD1 is induced by hyperglycemia in the retina of diabetic mice in a manner that contributes to neuronal cell death and visual dysfunction. One potential mechanism whereby REDD1 promotes neuronal apoptosis is through upregulation of reactive oxygen species (ROS), as the protein forms a pro-oxidant complex. In the retina of streptozotocin-induced diabetic mice, ROS levels, neuronal cell death, and REDD1 expression were increased concomitant with attenuation of contrast sensitivity thresholds, as assessed by behavioral optomotry. In R28 retinal cells in culture, hyperglycemic conditions increased REDD1 expression, ROS levels, and cell death. However, addition of the antioxidant N-acetyl-L-cysteine (NAC) to culture medium was sufficient to prevent the increase in ROS and cell death in response to hyperglycemic conditions. Moreover, REDD1-deficient cells did not exhibit increased ROS or cell death in response to hyperglycemic conditions. Similarly, in REDD1-deficient diabetic mice, ROS levels and cell death in retina were similar to that observed in nondiabetic mice. Finally, oral administration of NAC improved contrast sensitivity in diabetic mice relative to vehicle treated diabetic controls, demonstrating a key role for ROS levels in diabetes-induced visual dysfunction. Overall, the findings support therapeutic approaches targeting REDD1 and ROS production in the prevention of diabetes-induced visual dysfunction. Disclosure W.P. Miller: None. A. Toro: None. M.D. Dennis: None.

Visual Outcomes and Higher Order Aberrations Following LASIK on Eyes with Low Myopia and Astigmatism.

Background:Laser-Assisted in situ Keratomileusis (LASIK) can induce corneal aberrations that can impact vision and patient satisfaction. Recent developments in laser technologies have helped minimise these aberrations.Objective:To assess the quality of vision and change in Higher-Order Aberrations (HOAs) following wavefront-optimized LASIK in low-myopic astigmatic patients.Methods:LASIK was performed on a total of 76 eyes in patients with myopia <4.0 D and cylinder <2.0 D using the WaveLight® EX500 excimer and FS200 femtosecond laser platform. Visual acuity, contrast sensitivity and HOAs were measured at 1 and 3 months postoperatively and compared to preoperative values. Subjective quality of vision was assessed pre- and postoperatively using a VF14 questionnaire.Results:Mean postoperative Spherical Equivalent (SE) was -0.09 ± 0.26 µm with 95% of patients within ± 0.5 D of attempted SE. Postoperative uncorrected distance visual acuity was 20/20 or better for 96% of patients. Contrast sensitivity increased against horizontal and vertical gratings at all spatial frequencies except for vertical gratings at 18 cycles/degree. Spherical aberration and total HOA increased by 0.085 µm and 0.13 µm respectively. The mean VF14 score increased from 89.2 ± 16.7% to 99 ± 1.4% postoperatively.Conclusion:LASIK performed using the WaveLight® EX500 excimer and WaveLight® FS200 laser platform provided improved contrast sensitivity and visual acuity with minimal introduction of HOAs, making it a suitable platform for low myopic astigmatic patients.

Endogenous attention improves perception in amblyopic macaques

Amblyopia, a developmental disorder of vision, affects many aspects of spatial vision as well as motion perception and some cognitive skills. Current models of amblyopic vision based on known neurophysiological deficiencies have yet to provide an understanding of the wide range of amblyopic perceptual losses. Visual spatial attention is known to enhance performance in a variety of detection and discrimination tasks in visually typical humans and nonhuman primates. We investigated whether and how voluntary spatial attention affected psychophysical performance in amblyopic macaques. Full-contrast response functions for motion direction discrimination were measured for each eye of six monkeys: five amblyopic and one control. We assessed whether the effect of a valid spatial cue on performance corresponded to a change in contrast gain, a leftward shift of the function, or response gain, an upward scaling of the function. Our results showed that macaque amblyopes benefit from a valid spatial cue. Performance with amblyopic eyes viewing showed enhancement of both contrast and response gain whereas fellow and control eyes' performance showed only contrast gain. Reaction time analysis showed no speed accuracy trade-off in any case. The valid spatial cue improved contrast sensitivity for the amblyopic eye, effectively eliminating the amblyopic contrast sensitivity deficit. These results suggest that engaging endogenous spatial attention may confer substantial benefit to amblyopic vision.

Reducing Spatial Uncertainty Through Attentional Cueing Improves Contrast Sensitivity in Regions of the Visual Field With Glaucomatous Defects.

PurposeCurrent clinical perimetric test paradigms present stimuli randomly to various locations across the visual field (VF), inherently introducing spatial uncertainty, which reduces contrast sensitivity. In the present study, we determined the extent to which spatial uncertainty affects contrast sensitivity in glaucoma patients by minimizing spatial uncertainty through attentional cueing.MethodsSix patients with open-angle glaucoma and six healthy subjects underwent laboratory-based psychophysical testing to measure contrast sensitivity at preselected locations at two eccentricities (9.5° and 17.5°) with two stimulus sizes (Goldmann sizes III and V) under different cueing conditions: 1, 2, 4, or 8 points verbally cued. Method of Constant Stimuli and a single-interval forced-choice procedure were used to generate frequency of seeing (FOS) curves at locations with and without VF defects.ResultsAt locations with VF defects, cueing minimizes spatial uncertainty and improves sensitivity under all conditions. The effect of cueing was maximal when one point was cued, and rapidly diminished when more points were cued (no change to baseline with 8 points cued). The slope of the FOS curve steepened with reduced spatial uncertainty. Locations with normal sensitivity in glaucomatous eyes had similar performance to that of healthy subjects. There was a systematic increase in uncertainty with the depth of VF loss.ConclusionsSensitivity measurements across the VF are negatively affected by spatial uncertainty, which increases with greater VF loss. Minimizing uncertainty can improve sensitivity at locations of deficit.Translational RelevanceCurrent perimetric techniques introduce spatial uncertainty and may therefore underestimate sensitivity in regions of VF loss.

First and second eye cataract surgery and driver self-regulation among older drivers with bilateral cataract: a prospective cohort study

BackgroundDriving a car is the most common form of transport among the older population. Common medical conditions such as cataract, increase with age and impact on the ability to drive. To compensate for visual decline, some cataract patients may self-regulate their driving while waiting for cataract surgery. However, little is known about the self-regulation practices of older drivers throughout the cataract surgery process. The aim of this study is to assess the impact of first and second eye cataract surgery on driver self-regulation practices, and to determine which objective measures of vision are associated with driver self-regulation.MethodsFifty-five older drivers with bilateral cataract aged 55+ years were assessed using the self-reported Driving Habits Questionnaire, the Mini-Mental State Examination and three objective visual measures in the month before cataract surgery, at least one to three months after first eye cataract surgery and at least one month after second eye cataract surgery. Participants’ natural driving behaviour in four driving situations was also examined for one week using an in-vehicle monitoring device. Two separate Generalised Estimating Equation logistic models were undertaken to assess the impact of first and second eye cataract surgery on driver-self-regulation status and which changes in visual measures were associated with driver self-regulation status.ResultsThe odds of being a self-regulator in at least one driving situation significantly decreased by 70% after first eye cataract surgery (OR: 0.3, 95% CI: 0.1–0.7) and by 90% after second eye surgery (OR: 0.1, 95% CI: 0.1–0.4), compared to before first eye surgery. Improvement in contrast sensitivity after cataract surgery was significantly associated with decreased odds of self-regulation (OR: 0.02, 95% CI: 0.01–0.4).ConclusionsThe findings provide a strong rationale for providing timely first and second eye cataract surgery for older drivers with bilateral cataract, in order to improve their mobility and independence.

Results of neuroprotective therapy in primary open-angle glaucoma

To determine the relationships between the changes in functional parameters of vision that occur in primary open-angle glaucoma (POAG) patients on neuroprotective therapy. The study included 146 patients with stages I-III POAG aged 40 to 85 years. The patients were randomly divided into the study group and the control group at 2:1 ratio. All patients received traditional neuroprotective therapy. Patients of the study group were additionally treated with Retinalamine (#10, intramuscularly, one course). The patients were examined during the initial visit, then after 1 and 3 months; the examination included collection of anamnesis data, visometry, Maklakov tonometry, ophthalmoscopy, Förster white stimulus field of vision test, photostress test, and contrast sensitivity test. Examination data are included in the analysis. In the setting of drug therapy, patients showed widening of the visual field, improvement of uncorrected visual acuity and contrast sensitivity, and reduction of photostress test recovery time. Direct correlation was found between Retinalamine use, and uncorrected visual acuity and contrast sensitivity; it also had negative correlation with photostress test result. No adverse events occurred during the course of the study. Retinalamin (Russia) has prolonged neuroprotective effect in glaucoma. The drug is most effective in glaucoma stages I A and II A.

Closed-circuit television systems : Current importance and tips on adaptation and prescription

Closed-circuit television systems (CCTVs) have become an indispensable tool in rehabilitating low vision patients. Compared to optical visual aids, apart from providing maximum magnification these devices have the additional advantage of improved contrast sensitivity and an enlarged field of view. They are often the only visual aid enabling patients to regain reading ability. Our data reflect adecrease in the number of prescriptions caused by improved counseling of low-vision patients. Any prescription of reading aids must be preceded by comprehensive testing and counseling. More recent developments, such as electronic magnifiers are becoming increasingly more important but they are no substitute for CCTV.