Reduced Contrast Sensitivity Research Articles

Reduced Contrast Sensitivity Function in Central and Peripheral Vision by Disability Glare.

Various glares can decrease visual performance and cause discomfort, thus increasing drivers' risk for traffic accidents in real life. The current study aimed to systematically investigate glare sensitivity in the central and peripheral visual fields by measuring contrast sensitivity function (CSF) under nonglare, steady glare, and transient glare conditions. Nine observers with normal visual acuity in the dominant eye were enrolled. The CSF in central and peripheral vision (the 5° upper left visual field) was measured in a mesopic environment while the stimulus was displayed under three conditions: nonglare, steady glare, and transient glare. An orientation identification task was used to obtain the CSF. After the experiment, the observers were asked to report their level of discomfort in the presence of the glare. The area under the log CSF (AULCSF) and cut-off spatial frequency served as indicators of visual performance. In agreement with previous studies, both steady and transient glare reduced the AULCSF and cut-off frequency. However, the AULCSF and cut-off frequency were reduced more for central vision than for nearly peripheral vision. In addition, the extent of the decreases in the AULCSF and cut-off frequency was greater for steady glare than for transient glare; in contrast, more discomfort was associated with transient glare than steady glare.

THE PROGRESSION OF MACULAR STRUCTURAL AND FUNCTIONAL CHANGES IN LATE-ONSET RETINAL DEGENERATION.

To characterize the progression of structural and functional changes in the retinas of a small cohort of unrelated patients with early late-onset retinal degeneration and evaluate these changes as potential biomarkers for future treatment trials. Best-corrected visual acuity, contrast sensitivity, Goldman visual fields, retinal sensitivity measurement by mesopic microperimetry, extent of ellipsoid zone disruption using spectral domain optical coherence tomography, and fundus autofluorescence imaging were performed at each biennial visit. Three unrelated patients with molecularly confirmed late-onset retinal degeneration (S163R mutation in C1QTNF5 ) were prospectively followed for 4 years. The patient's ages were 44, 54, and 62 at baseline. Over the 4-year follow-up period, one patient demonstrated a significant reduction in best-corrected visual acuity (6 Early Treatment of Diabetic Retinopathy Study letters), whereas two patients suffered a significant reduction in contrast sensitivity. Early in the disease, there was a close relationship between ellipsoid zone disruption and a loss in retinal sensitivity. Later in the course of the disease, there were areas outside the zones of ellipsoid zone disruption that also suffered progressive loss of retinal sensitivity, suggesting that ellipsoid zone loss was not the only factor responsible for the loss of retinal sensitivity. Changes in fundus autofluorescence and Goldman visual field loss were not closely related to changes in ellipsoid zone disruption or retinal sensitivity loss. This study has found that the monitoring of the progression of ellipsoid zone disruption and changes in mesopic microperimetry may be useful biomarkers in future clinical trials in patients with late-onset retinal degeneration.

Dopaminergic Retinal Cell Loss and Visual Dysfunction in Parkinson Disease.

Considering the demonstrated implication of the retina in Parkinson disease (PD) pathology and the importance of dopaminergic cells in this tissue, we aimed to analyze the state of the dopaminergic amacrine cells and some of their main postsynaptic neurons in the retina of PD. Using immunohistochemistry and confocal microscopy, we evaluated morphology, number, and synaptic connections of dopaminergic cells and their postsynaptic cells, AII amacrine and melanopsin-containing retinal ganglion cells, in control and PD eyes from human donors. In PD, dopaminergic amacrine cell number was reduced between 58% and 26% in different retinal regions, involving a decline in the number of synaptic contacts with AII amacrine cells (by 60%) and melanopsin cells (by 35%). Despite losing their main synaptic input, AII cells were not reduced in number, but they showed cellular alterations compromising their adequate function: (1) a loss of mitochondria inside their lobular appendages, which may indicate an energetic failure; and (2) a loss of connexin 36, suggesting alterations in the AII coupling and in visual signal transmission from the rod pathway. The dopaminergic system impairment and the affection of the rod pathway through the AII cells may explain and be partially responsible for the reduced contrast sensitivity or electroretinographic response described in PD. Also, dopamine reduction and the loss of synaptic contacts with melanopsin cells may contribute to the melanopsin retinal ganglion cell loss previously described and to the disturbances in circadian rhythm and sleep reported in PD patients. These data support the idea that the retina reproduces brain neurodegeneration and is highly involved in PD pathology. ANN NEUROL 2020;88:893-906.

Visual performance and patient satisfaction after implantation of extended range-of-vision IOLs: bilateral implantation vs 2 different mix-and-match approaches.

To compare the visual outcomes and patient satisfaction after bilateral implantation of an extended range-of-vision intraocular lens (ERoV IOL) (Tecnis Symfony) vs 2 different mix-and-match approaches combining the ERoV IOL with bifocal IOLs. Glory Seoul Eye Clinic, Seoul, South Korea. Prospective observational nonrandomized comparative study. Patients undergoing cataract surgery were distributed into 3 groups based on their lifestyle and near visual demands: bilateral Symfony IOL, mix-and-match Symfony IOL with bifocal +3.25 diopters (D) IOL, and Symfony IOL with bifocal +4.0 D IOL. Binocular uncorrected visual acuity for distance, intermediate, and near, manifest refraction, defocus curve, contrast sensitivity, and subjective visual perception and satisfaction (photic phenomena, spectacle independence, and patient satisfaction) were evaluated at 1 week, 1 month, and 3 months postoperatively. The study comprised 103 people (206 eyes). There were no significant differences for uncorrected visual acuity between groups for distance, intermediate, and near vision (P > .05). Contrast sensitivity under low and high luminance conditions was not different between groups (P > .05). Influence of glare on image perception was found to reduce contrast sensitivity more in the bilateral group for smaller target sizes (P < .05). Patients implanted bilaterally with Symfony IOLs reported photic phenomena more frequently than those implanted with the mix-and-match combinations. All combinations evaluated provided good visual outcomes for distance, intermediate, and near. The lower incidence of photic phenomena reported by patients, and the lower reduction on contrast sensitivity for low illumination levels with the presence of glare, suggest that mix-and-match approaches might be a better option compared with bilateral implantation of ERoV IOLs.

Correlation in acute CSCR between hyperreflectivity on the infrared image in optical coherence tomography and fluorescein angiography.

To determine the association between hyperreflective area identified on the reference image (en-face image) in spectral domain optical coherence tomography (SD-OCT) scan and the leak on fluorescein angiography in patients with acute treatment naive central serous chorioretinopathy (CSCR). Retrospective, observational chart review. The reference image (en-face) image on SD OCT raster scan was examined for the presence of a hyperreflective spot and an attempt was made to correlate its location on the actual leak seen on FFA using anatomical landmarks as reference. Follow up was 6 months after CSCR resolution. Appropriate statistical analysis was made. Sixty-two patients (65 eyes; 49 males) with CSCR were identified of which 62/65 eyes (95.38%) showed the said correlation. The mean age was 31.24 years. The mean follow-up was 17.25 months. The mean BCVA at baseline was 0.28 logMAR. The mean final BCVA was 0.08. The hyperreflective spot noted on the infrared (reference) image correlated the most with the classic ink-blot leakage as well as the minimally enhancing/ill-defined leakage pattern. In 37/41 eyes, the area of hyperreflectivitiy correlated with the pigment epithelial detachment. The hyperreflective spot resolved in most patients who received photodynamic therapy but persisted in most patients who received eplerenone therapy. Persistent hyperreflectivity after subretinal fluid resolution appeared to correlate with persistent metamorphopsia and reduced contrast sensitivity in eyes with no subretinal fluid. We demonstrate an interesting correlation between the area of leak and the OCT reference image (en face) used to determine the level of the scan. The study looks at the potential applicability of a correlation between leaking areas on fundus fluorescein angiography and a hyperreflective area on the infrared image in optical coherence tomography (OCT) in patients with central serous chorioretinopathy (CSCR).

Ocular manifestations of Parkinson disease

Background: Parkinson's disease (PD) is the second most common neurodegenerative disorder. We aimed to review both the disease and the drug-related ocular manifestations of PD.&#x0D; Methods: In this manuscript, we have reviewed and summarized existing literature on the ocular manifestations and drug-related complications of PD. We have also discussed the use of current noninvasive imaging techniques, such as optical coherence tomography (OCT), for the early diagnosis and monitoring of PD.&#x0D; Results: Impaired color vision, reduced stereopsis, reduced contrast sensitivity, pupillary abnormalities, eye movement disorders, convergence insufficiency, dry eye syndrome, glaucoma, visual dysfunctions, retinal abnormalities, and drug-related side effects were among the listed ocular manifestations of PD. There is a large knowledge gap regarding the type of glaucoma affecting PD patients—whether it is open-angle or other types. Further case studies and long-term follow-ups during PD progression are necessary to fill this gap. Patient compliance with follow-up visits for more visual field tests and OCT during PD progression may become problematic when dementia and cognitive impairment occur.&#x0D; Conclusions: There is a general need for clinicians to perform further tests and more visual examinations to rule out ocular manifestations. Furthermore, additional clinical trials are needed to further evaluate the use of different types of OCT findings as biomarkers of PD progression. This would aid in early diagnosis and in delaying disease progression, if treated promptly.

Prevalence of Charles Bonnet syndrome in patients with glaucoma: a systematic review with meta-analyses.

Glaucoma is a widespread sight-threatening condition often only recognized when very pronounced. It is initially characterized by peripheral visual field losses, while advanced stages also affect the central vision. Some of these patients may experience visual hallucinations, the Charles Bonnet syndrome (CBS). In this systematic review and meta-analysis, we provide an overview of the literature dealing with the prevalence of CBS in patients with glaucoma. We searched the databases PubMed/MEDLINE, Embase, Web of Science, the Cochrane Central and PsycInfo on 22 March 2020. Eight studies (n=827 patients) were identified and included for a qualitative and quantitative analysis. No studies included a representative sample of patients with only glaucoma. In patients with glaucoma in different stages and with ocular comorbidities, prevalence of CBS was 2.8% (CI95%: 0.7-6.1%). Among patients with glaucoma where all had bilateral low visual acuity, prevalence of CBS was 13.5% (CI95%: 8.4-19.6%). In patients with glaucoma who visited vision rehabilitation clinics, presumably due to an extensive vision impairment, prevalence of CBS was 20.1% (CI95%: 16.8-23.6%). Risk factors of CBS besides low vision were high age, female gender, reduced contrast sensitivity and not living alone. Taken together, we find that CBS may not be rare in patients with advanced glaucoma with and without ocular comorbidities. However, limitations of the current literature should be highlighted and careful approach towards conclusions is important. More studies are needed to better understand the prevalence and risk factors among different populations of patients with glaucoma.

Visual outcomes after bilateral implantation of a new generation diffractive trifocal intraocular lens

Cataract surgery today has become more of a refractive surgery with high patient expectations and demand of independence from glasses. Modern cataract surgery is characterized by obtaining precise postoperative target refraction with the premium intraocular lenses (IOLs) available today. The multifocal IOLs are designed to reduce the spectacle dependence after cataract surgery. Previously a variety of studies were performed that confirmed a significant improvement in uncorrected visual acuity after implantation of multifocal IOLs as compared to monofocal IOLs.1‒5 Initially multifocal IOLs that were designed were having a bifocal design which allowed the patient to have a good distance and near visual acuity post operatively, but near vision came at the expense of reduced contrast sensitivity.6‒8 Nowadays, due to increased use of computers the preference of spectacles has changed from near to intermediate distance. In this sense achieving an intermediate vision with an IOL is a good option. The IOL technologies in the latest times help in rehabilitating the distance and near visual acuities and also by incorporating a component of intermediate vision (ie, trifocal IOLs) to ensure spectacle independence.9‒11 The present study aims at assessing the performance of AT LISA tri 839MP trifocal diffractive IOL in terms of visual acuity and independence from spectacles. The other objectives are to assess changes in the distance, near and intermediate visual acuities, contrast sensitivity postoperatively and plotting the defocus curves.

Promising recovery biomarkers after first event acute demyelinating optic neuritis

BackgroundAcute demyelinating optic neuritis is often a first episode of subsequent CNS demyelinating disease, most frequently multiple sclerosis (MS). The majority of the patients have substantial recovery of the high contrast visual acuity (HCVA) and 30-2 perimetry, but reduced contrast sensitivity persists in 56% of eyes after an episode of optic neuritis. Cross sectional studies of MS patients show low contrast visual acuity (LCVA) correlates modestly with RNFL thickness and macula ganglion cell +IPL layer (GCL) thickness. Considering the potential severity of the vision deficits at onset, and GCL thinning at outcome, we hypothesized 10-2 perimetry and LCVA deficits would be frequent following an episode of optic neuritis. MethodsWe prospectively studied 32 eyes of 32 patients (9 men, 23 women, age 34 years ± 10) with first time acute optic neuritis. We measured LCVA 2.5% (# letters seen), GCL thickness and loss, and 10-2 mean deviation (MD in decibels, dB) within 15 days from symptoms onset and at six months. The 10-2 threshold perimetry, a novel assessment in the MS research field, included to further characterize central vision function. We used correlation analysis to assess associations between GCL thickness and thinning and 10-2 perimetry as well as LCVA 2.5% at six months. ResultsCompared to fellow eyes we found significant residual LCVA deficits in 28/32 study eyes at 6 months with 12.6 ± 15.8 letters seen, p=0.001). Similarly, 10-2 MD threshold perimetry in the study eyes at 6 months showed significant difference relative to the fellow eyes, p=0.01.In regards to GCL changes at 6 months, we found statistically significant reduction of the GCL thickness in the study eyes relative to the fellow eyes (study eyes 69.6 ± 9.6 µm, fellow eyes 82.7 ± 4.7 µm, p=0.001), with thinning present in 29/32 eyes. The mean GCL thinning at 6 months in the study eyes was 12.4 ± 8.4 µm.Correlation analysis of associations between primary outcome measures at 6 months showed significant relationship between GCL thickness and 10-2 MD threshold perimetry (0.43, p = 0.015) but not with LCVA. At six months, the mean GCL thinning strongly correlated with the 10-2 MD (-0.60, p=0.01) and moderately with LCVA (-0.46, p=0.008). ConclusionsGCL thickness is the best structural and LCVA and 10-2 MD are sensitive functional measures for determining residual deficits due to optic neuritis. The 10-2 MD correlates best with the outcome GCL thickness and loss. Our findings also suggest that 10-2 threshold perimetry and macular GCL can provide functional and structural promising biomarker signals to explore neuro-protective research.

The relationship between neurovascular coupling, vision and sensory performance, and concussion history in Special Operations Forces combat soldiers

Objective To determine the relationship between neurovascular coupling (NVC), vision and sensory performance in Special Operations Forces (SOF) combat soldiers with and without concussion history. Methods We studied 61 SOF combat soldiers (male, age = 33.8 ± 3.7 years, n = 40 with concussion history [Median = 3; range = 1–10+]). We instrumented our participants with transcranial Doppler to quantify NVC response during reading and visual search tasks. All participants completed vision and sensory performance testing (Senaptec Sensory Station). We performed separate multiple regressions to determine if relationships between NVC and vision and sensory performance testing existed while controlling for concussion history, and to investigate the interaction between NVC and concussion history. Results Those with higher visual search NVC response magnitudes demonstrated significantly worse contrast sensitivity when controlling for concussion history (F 1,60=4.57, ß = 0.03, p = .04, R 2 = 12.6%). We did not observe any other significant relationships between NVC and visual and sensory performance tests nor did we observe any significant interactions between NVC and concussion history (p > .05). Conclusions Heightened NVC response magnitudes are related to reduced contrast sensitivity in SOF combat soldiers. Because concussion history does not impact the relationships between outcomes, these measures may be utilized for performance evaluation at any point in a soldier’s career. The lack of relationships between NVC response magnitude and some of the other vision and sensory performance outcomes suggests that implementing NVC assessment may add unique information and enable clinicians to detect physiological deficits that may otherwise go undetected.

Considerations of Visual Quality in Ocular Surgery as Presented at Dry Eye University

Visual quality may be described as the visual experience which reflects the optimal optical efficiency of the eye. Patients undergoing ocular surgery expect improvement in visual acuity. Ocular surgeons typically aim to improve best-corrected visual acuity. Refractive surgeons, on the other hand, strive to improve uncorrected visual acuity. It is not uncommon that patients with excellent corrected visual acuity following surgery may be dissatisfied with visual quality which is less than anticipated due to unexpected visual disturbances. These visual phenomena may include ghosting, glare, halos, reduced contrast sensitivity, and visual fluctuation.

Correlation between Retinal Nerve Fibre Layer Thickness and Glycosylated Haemoglobin in Non Proliferative Diabetic Retinopathy

Abstract Background Diabetes mellitus is a metabolic disorder characterized by chronic hyperglyaemia. Diabetes cause many complication. diabetic retinopathy is common complication which affects up to 80 percent of all patients who have diabetes for more than10 years or more. Retinal functional abnormalities as reduced contrast sensitivity and ERG abnormalities could be detected in diabetic patients before microvascular lesions can be detected in ophalmological examination. Purpose to determine correlation between retinal nerve fibre layer thickness measured by Optical coherence tomography and glycosylated haemoglobin in type 2 non proliferative diabetic retinopathy. Patients and Methods In our study was conducted on patient recruited from National institute of Diabetes and endocrinology in the ophthalmic clinic. Patients were evaluated for peri-papillary retinal nerve fibre layer ( RNFL) thickness by optical coherence tomography (RS 3000 advance). Blood were taken for HbA1c. The study was included 164 eyes from 87 patients. The patients were non proliferative diabetic retinopathy(NPDR) classified into three groups according to Early Treatment Diabetic Retinopathy Study into; Mild group was 69 eyes from 35 patients, moderate group58 eyes from 31 patient, Severe group 37 eyes from 21 patients. Results The severe group show statistically significant difference with the others (P &amp;lt; 0.001) except with mild group in nasal and inferior quadrant, therefore the thickness was high in the severe groups because the edema in RNFL. In our study we observed decrease in total thickness of RNFL in peripapillary area. However, among each quadrant we observed that the superior quadrant was thinner compared to other quadrants (p &amp;lt; 0.001). There was insignificant correlation between RNFL thickness with the Glycosylated haemoglobin ( HbA1c )in all NPDR groups. Conclusion Early NPDR patients appear to have thinner RNFL thickness and severe NPDR patients show increasing RNFL thickness. There are not correlation between RNFL thickness and glycosylated haemoglobin.

Detection of structural and electrical disturbances in macula and optic nerve in Alzheimer’s patients and their correlation with disease severity

ABSTRACTAim: To evaluate and compare structural and functional changes in macula and optic nerve in Alzheimer disease (AD) patients and healthy subjects.Methods: Both eyes of 20 AD patients and 40 age-matched healthy controls were evaluated. All subjects were evaluated by cognitive testing and comprehensive ophthalmological examination, including visual acuity, visual fields, color vision, contrast sensitivity, anterior, and posterior segment examination, optical coherence tomography, multifocal electroretinography (mfERG), and pattern-reversal visual evoked potential (pVEP).Results: AD patients showed significantly reduced contrast sensitivity, thinner nerve fiber layer, ganglion cell layer andmacular volume. Multifocal ERG wave amplitudes were significantly reduced with delayed implicit times, which correlated significantly with the inner retinal layer thinning and poorer disease severity scores. The correlation with structural changes and disease severity was highest for pVEP, which showed significant derangement in AD patients.Conclusion: Subclinical visual dysfunction may be present in AD patients, which may be detected as inner retinal thinning. A probable photoreceptor abnormality may also form a part of the AD disease process.

Multifocal intraocular lenses and retinal diseases

PurposeMultifocal intraocular lenses (MIOLs) are often discouraged in patients with or at risk of retinal disorders (including diabetic retinopathy, age-related macular degeneration, and epiretinal membranes), as MIOLs are believed to reduce contrast sensitivity (CS). Concerns with MIOLs have also been raised in individuals with visual field defects, fixation instability or eccentric preferred retinal locations. The aim of this study is to review the influence of MIOL on quality of vision in patients with retinal diseases.MethodsWe reviewed the PubMed and Web of Science databases to identify relevant studies using the following keywords: multifocal intraocular lens, cataract surgery, cataract extraction, lens exchange, diabetic retinopathy, age-related macular degeneration, and contrast sensitivity.ResultsStudies evaluating CS in MIOLs present conflicting results: MIOLs either did not influence CS or resulted in worse performance under low-illuminance conditions and higher spatial frequencies when compared to monofocal IOLs. Nevertheless, MIOLs preserved CS levels within the age-matched normal range. Two studies reported that patients with concurrent retinal diseases receiving a MIOL, both unilaterally and bilaterally, reported a significant improvement in visual-related outcomes. Individuals with a monofocal IOL in one eye and a MIOL in the fellow eye reported greater subjective satisfaction with the MIOL.ConclusionWe were unable to find evidence suggesting that patients with retinal diseases should be advised against MIOLs. Nevertheless, more research is needed to address the aforementioned concerns and to optimize the use of MIOLs in eyes with retinal disease.

A Clinical Study of Optic Disc Edema in a Tertiary Eye Center of Nepal.

To evaluate the etiology and clinical presentation of cases with optic disc edema presenting to a tertiary eye center of Nepal. The etiology of optic disc edema ranges from relatively benign to potentially sight and life threatening conditions. Till date very few studies have been done on disc edema in Nepal. The authors conducted a prospective, descriptive study at B.P. Koirala Lions Center for Ophthalmic Studies (BPKLCOS), Nepal. All cases with disc edema presenting to the out patient department (OPD) from January 1, 2014 to June 30, 2015 were included in the study. Total 112 patients were included in the study, out of which diagnosis could be established in 99. The mean age of the patients was 32.54 ± 13.97 years with the majority being female. The most common cause of disc edema was idiopathic intracranial hypertension (IIH) (37.5%,). Majority of the patients complained of isolated diminution of vision (38.4%). Among the eyes affected, 78.3% had best corrected visual acuity (BCVA) 6/6-6/18, 36.6% had color vision defect and 31.4% had reduced contrast sensitivity. The most common visual field defect was isolated enlarged blind spot (39.7 %). IIH followed by optic neuritis (ON) are the most common causes of disc edema. Conditions with disc edema mainly affect the age group 21-40 years with females affected 2.5 times more than males. Visual acuity, color vision and contrast sensitivity are deranged in majority of cases of ON and normal in majority of cases of IIH.

Impact of OCT and visual function in multiple sclerosis patients treated with Fingolimod

AbstractPurposeTo evaluate the effect of Fingolimod during one year on the neuro‐retinal structures and visual function in patients with multiple sclerosis (MS).MethodsSeventy eight eyes of 78 patients with MS treated with Fingolimod were evaluated every 3 months (for a year) and compared with 32 MS patients treated with Interferon. All subjects underwent visual acuity (VA) test for high and low contrast (100%, 2.5% and 1.25%), contrast sensitivity vision (using the CSV‐1000 and Pelli‐Robson tests), color vision (using the Fansworth and L'Anthony D15 desaturated tests), the thickness of the retinal fiber layer, the ganglion cell layer and the macula by Fourier‐domain optical coherence tomography (OCT).ResultsIn MS patients treated with Fingolimod, a decrease in visual acuity was registered in 100% and 1.25% contrasts (p = 0.009 and p = 0.008respectivelly), as well as a reduction in contrast sensitivity in the Pelli‐Robson test (p &lt; 0.001). Structurally a decrease in the ganglion cell layer (p = 0.008) and an increase in macular thickness (p = 0.006) were found. In MS patients treated with Interferon there is a significant decrease only in ganglion cell layer thickness (p = 0.006), being this decrease higher than in the Fingolimod group (P &lt; 0.006).ConclusionsTreatment with Fingolimod causes a significant decrease in visual acuity and contrast sensitivity. It also causes an increase in average central macular thickness compared to the Interferon treatment. It's probable that the increase in central macular thickness is the cause of changes in visual function.

Selectively reduced contrast sensitivity in high schizotypy

Deficits in the ability to encode small differences in contrast between adjacent parts of an image (contrast sensitivity) are well documented in schizophrenic patients. In the present study, we sought to determine whether contrast sensitivity deficits reported in schizophrenic patients are also evident in those who exhibit high schizotypy scores in a typical (i.e., non-schizophrenic) population. Using the O-Life Questionnaire, we determined the effects of schizotypy on spatial (0.5, 2 and 8 c/deg) and spatiotemporal (0.5 and 8 c/deg at 0.5 and 8 Hz) contrast sensitivity in 73 young (18–26 years), majority female (n = 68) participants. We found differences in contrast sensitivity that were spatial, spatiotemporal and O-Life subscale specific. Spatial contrast sensitivity was significantly lower in high, compared to low schizotypes at low spatial frequencies (0.5 c/deg) in those who scored highly on the Unusual Experiences and Cognitive Disorganisation O-Life subscales. For moving stimuli, individuals with high scores on the Unusual Experiences subscale exhibited lower spatiotemporal contrast sensitivity for 0.5 and 8 c/deg patterns drifting at 8 Hz. Although the effects reported here were relatively small, this is the first report of reduced contrast sensitivity in schizotypy.

Contrast sensitivity before and after small incision lenticule extraction and femtosecond laser in situ keratomileusis

Introduction: Contrast sensitivity function after laser ablation of the cornea in refractive surgery is an important tool for measuring quality of visual function. The effect of small incision lenticule extraction (SMILE) and femtosecond laser in situ keratomileusis (FS-LASIK) on visual function can be compared by measuring spatial contrast sensitivity.&#x0D; Purpose: This study was to compare contrast sensitivity function in patients undergoing refractive surgery for myopia at Tilganga Institute of Ophthalmology.&#x0D; Methods: In a retrospective study, 15 subjects who underwent refractive surgeries comprising 9 cases of SMILE and 6 cases of FS-LASIK at Tilganga Eye Hospital were enrolled in the study. A major assessment included best corrected monocular contrast sensitivity with functional vision analyzer at spatial frequencies of 1.5, 3, 6, 12, and 18 cycles/deg in photopic condition (85 cd/m2) before, 3 months, and 1 year after the surgery. The average functional acuity contrast test scores for each spatial frequency were recorded. Differences between preoperative and postoperative contrast sensitivity at each spatial frequency were analyzed through parametric paired Student’s t-test.&#x0D; Results: Contrast sensitivity of postoperative FS-LASIK and SMILE did not differ from preoperative values at a photopic level. However, at high spatial frequency (12 and 18 cycles/deg), contrast sensitivity function improved significantly (p &lt; 0.05) in eyes after FS-LASIK. Eyes after SMILE surgery did not show any reduction in contrast sensitivity at all the spatial frequencies.&#x0D; Conclusion: Under photopic conditions, the contrast sensitivity function is unaffected by SMILE or FS-LASIK.

An Unexpected Spontaneous Motion-In-Depth Pulfrich Phenomenon in Amblyopia.

The binocular viewing of a fronto-parallel pendulum with a reduced luminance in one eye results in the illusory tridimensional percept of the pendulum following an elliptical orbit in depth, the so-called Pulfrich phenomenon. A small percentage of mild anisometropic amblyopes who have rudimentary stereo are known to experience a spontaneous Pulfrich phenomenon, which posits a delay in the cortical processing of information involving their amblyopic eye. The purpose of this study is to characterize this spontaneous Pulfrich phenomenon in the mild amblyopic population. In order to assess this posited delay, we used a paradigm where a cylinder rotating in depth, defined by moving Gabor patches at different disparities (i.e., at different interocular phases), generates a strong to ambiguous depth percept. This paradigm allows one to accurately measure a spontaneous Pulfrich phenomenon and to determine how it depends on the spatio-temporal properties of stimulus. We observed a spontaneous Pulfrich phenomenon in anisometropic, strabismic, and mixed amblyopia, which is posited to be due to an interocular delay associated with amblyopic processing. Surprisingly, the posited delay was not always observed in the amblyopic eye, was not a consequence of the reduced contrast sensitivity of the amblyopic eye, and displayed a large variability across amblyopic observers. Increasing the density, decreasing the spatial frequency, or increasing the speed of the stimulus tended to reduce the observed delay. The spontaneous Pulfrich phenomenon seen by some amblyopes was variable and depended on the spatio-temporal properties of the stimulus. We suggest it could involve two conflicting components: an amblyopic delay and a blur-based acceleration.

Ocular abnormalities in beta thalassemia patients: prevalence, impact, and management strategies.

Beta thalassemia (β-thalassemia) is a hereditary disease caused by defective globin synthesis and can be classified into three categories of minor (β-TMi), intermedia (β-TI), and major (β-TM) thalassemia. The aim of our study is to investigate the effects of β-thalassemia and its treatment methods on different parts of the eye and how early-diagnostic methods of ocular complications in this disorder would prevent further ocular complications in these patients by immediate treatment and diet change. We developed a search strategy using a combination of the words Beta thalassemia, Ocular abnormalities, Iron overload, chelation therapy to identify all articles from PubMed, Web of Science, Scopus, and Google Scholar up to December 2018. To find more articles and to ensure that databases were thoroughly searched, the reference lists of selected articles were also reviewed. Complications such as retinopathy, crystalline lens opacification, color vision deficiency, nyctalopia, depressed visual field, reduced visual acuity, reduced contrast sensitivity, amplitude reduction in a-wave and b-wave in Electroretinography (ERG), and decrease in the Arden ratio in Electrooculography (EOG) have all been reported in β-thalassemia patients undergoing chelation therapy. Ocular problems due to β-thalassemia may be a result of anemia, iron overload in the body tissue, side effects of iron chelators, and the complications of orbital bone marrow expansion.