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Increasing surgical refinement of procedures to meet both biologic and esthetic demands of patients is seen in today's periodontal practice. For these new technologies, instruments, and surgical techniques are necessary. Technical skills of the clinician are challenged by the limit of range of visual acuity. Periodontal microsurgery improves the outcome of basic periodontal surgical procedures by enhancing normal vision through magnification along with favorable lighting system. It gives enhanced outcomes not possible with traditional macrosurgery in terms of passive wound closure and reduced tissue trauma. The purpose of this review is to provide brief knowledge of periodontal microsurgery: the role of magnification, microsurgical instrumentation and applications of microsurgery.

Purpose: To examine the effects of gaze position and optical blur, similar to that used in multifocal corrections, on stepping accuracy for a precision stepping task among older adults. Methods: Nineteen healthy older adults (mean age, 71.6 +/- 8.8 years) with normal vision performed a series of precision stepping tasks onto a fixed target. The stepping tasks were performed using a repeated-measures design for three gaze positions (fixating on the stepping target as well as 30 and 60 cm farther forward of the stepping target) and two visual conditions (best-corrected vision and with +2.50DS blur). Participants' gaze position was tracked using a head-mounted eye tracker. Absolute, anteroposterior, and mediolateral foot placement errors and within-subject foot placement variability were calculated from the locations of foot and floor-mounted retroreflective markers captured by flash photography of the final foot position. Results: Participants made significantly larger absolute and anteroposterior foot placement errors and exhibited greater foot placement variability when their gaze was directed farther forward of the stepping target. Blur led to significantly increased absolute and anteroposterior foot placement errors and increased foot placement variability. Furthermore, blur differentially increased the absolute and anteroposterior foot placement errors and variability when gaze was directed 60 cm farther forward of the stepping target. Conclusions: Increasing gaze position farther ahead from stepping locations and the presence of blur negatively impact the stepping accuracy of older adults. These findings indicate that blur, similar to that used in multifocal corrections, has the potential to increase the risk of trips and falls among older populations when negotiating challenging environments where precision stepping is required, particularly as gaze is directed farther ahead from stepping locations when walking.

Introduction: Strabismus is known to affect health related quality of life in adults. This study was conducted to compare the quality of life among strabismic and non strabismic visually normal adults.Methods: A prospective cross sectional study was conducted at Nepal Eye Hospital for two years. Fifty three adults with strabismus and fifty three adults without strabismus and normal vision were enrolled. Twenty open ended adult strabismus questionnaire (AS-20) developed by Hatt et al were used to assess the impact of strabismus on patient’s health related quality of life. All the participants reviewed AS-20 instructions for patients prior to completing the questionnaire. The overall AS-20 score was calculated as a mean of all 20 item scores. The psychosocial subscale was calculated as a mean of items 1-10 (inclusive). Function subscale was calculated as a mean of items 11-20 (inclusive).The mean overall and subscale scores were compared between strabismic patients and non-strabismic visually normal adults using Mann Whitney U test.Results: Mean overall scores decreased for patients with strabismus as compared to non strabismic visually normal adults. Mean psychosocial scale among strabismic patients and non strabismic patients was 47.53 ± 24.840 and 95.42 ± 9.631 respectively and mean function subscale among the two groups were 63.57±22.652 and 83.91±13.592 respectively. There was statistical difference in the overall score, psychosocial as well as function subscale between the strabismic and non strabismic visually normal adults (p value 0.00).Conclusion: The overall quality of life appears to be adversely affected in people with strabismus in comparison to the ones without strabismus. Strabismus, being a treatable condition, should not be ignored and corrective measures should be undertaken.

Purpose: The purpose of this study was to investigate the change of contrast sensitivity by prescribing tinted lenses and to provide the clinical manual. Methods: Contrast sensitivity was measured for twenty adults with normal vision while they wore yellow, orange and green tinted lenses. To measure contrast sensitivity, the 5 spatial frequencies (2, 4, 6, 8 and 10 cpd) were used for 33 ms and 233 ms, respectively. Results: The contrast sensitivity was overall higher with 233 ms than 33 ms (p0.64) Conclusions: Yellowish tinted lens that reduces chromatic aberration and the scattering is prescribed for the various purposes to improve visual functions. Before prescribing tinted lens, identifying characteristic of user and tinted lens for cut off wavelengths is recommended.

This study investigated the effects of target distance (30, 35, and 40 cm) and the color of background lighting (red, green, blue, and yellow) on the duration of movements made by participants with low vision, myopia, and normal vision while performing a reaching task; 48 students (21 women, 27 men; M age = 21.8 year, SD = 2.4) participated in the study. Participants reached for a target (a white LED light) whose vertical position varied randomly across trials, ranging in distance from 30 to 40 cm. Movement time was analyzed using a 3 (participant group) × [4 (color of background lighting) × 3 (movement distance)] mixed-design ANOVA model. Results indicated longer times for completing a reaching movement when: participants belonged to the low vision group; the target distance between the starting position and the target position was longer (40 cm); and the reaching movement occurred in the red-background lighting condition. These results are particularly relevant for situations in which a user is required to respond to a signal by reaching toward a button or an icon.

To evaluate the effects of corrective surgery in adult strabismic patients with visual deficits and the stability of postoperative alignments.Retrospective study. Alignment and binocular visual function were evaluated in adult patients with visual deficits (best corrective visual acuity (BCVA)0.3 in one or both eyes) with at least 6 months postoperative follow-up. The results in these patients were compared to those in patients with normal or nearly normal vision (BCVA ≥ 0.6 in the worse eye) matched by the type of strabismus, magnitude of deviation, age at the time of corrective surgery, and length of time before final follow-up.Sixty-four patients aged 28.3 ± 12.0 (17~65) years were included in the visual deficit group, and 64 subjects aged 26.8 ± 9.4 (17~58) years were included in the matched control group. No significant difference was found in the age or deviation angle between the two groups. The surgery was considered a success in 42 patients (65.6%) in the visual deficit group and 55 patients (86%) in the control group at the last visit (ΧAdults with poor vision experienced positive results from corrective surgery via a postoperative shift toward exotropia. Full correction of deviation and postoperative shift should be considered before surgery.

Orbital complications in sickle cell disease are uncommon, but can be severe enough to result in significant morbidity. We report a 10-year-old boy with sickle cell disease who presented with fever, bilateral eyelid edema, proptosis, and diminished vision with left eye involvement more than the right eye. Investigations revealed anemia, thrombocytopenia, and derangement of coagulation profile consistent with disseminated intravascular coagulopathy, and salmonella species was recovered from blood culture. MRI of the orbits showed bilateral large subperiosteal hematomas. The treatment included intravenous antibiotics, pulse methylprednisolone and bilateral canthotomy with surgical drainage of the hematomas. Postoperative visual assessment revealed complete loss of vision in the left eye with normal vision in right eye. This case highlights the importance of the early evaluation and consideration of surgical intervention in sickle cell disease with this rare complication.

To compare the rates of amblyopia and treatment outcomes in children 0-2 years to those of children aged 3-5 years referred from a well-established community-based photoscreening program.The medical records of children who failed vision photoscreening through Iowa KidSight and were subsequently seen at the University of Iowa for a complete eye examination over a 13-year period were retrospectively reviewed. Outcome measures were the number of children obtaining normal vision, the age at which normal vision was attained, and the elapsed time from screening examination to first documentation of normal vision.Of 319 subjects, 67 (21%) were 0-2 years of age and 252 (79%) were at least 3 years of age at screening. Amblyopia was found in 19% of the younger group and 30% of the older group (P = 0.12). Follow-up time was similar between groups. At final follow-up, 8% of children in the younger group did not attain normal vision, compared with 40% in the older group (OR = 8.92; 95% CI, 1.65-92.95; P = 0.009). Normal vision was attained on average at 35 months of age in the younger group and 69 months in the older group (P 0.0001).In our study cohort, children3 years of age were found to have an equivalent rate of amblyopia compared with children ≥3 of age. Those screened between ages 0-2 years of age attained normal vision at a significantly younger age and were more likely to attain normal vision.

Purpose : There is little research evidence to explain why older adults have more problems adapting to new spectacles incorporating astigmatic changes than younger adults. We tested the hypothesis that astigmatic lenses oriented obliquely would lead to errors in verticality perception that are greater for older than younger adults. Methods : Participants included 12 young (mean ± SD age 25.1 ± 5.0 years) and 12 older (70.2 ± 6.3 years) adults with normal vision. Verticality perception was assessed using a computer-based subjective visual vertical (SVV) task, under static and dynamic (in the presence of a moving peripheral distractor) conditions and when viewing targets through the near refractive correction (control condition), and two forms of astigmatic lenses oriented in the vertical, horizontal, and oblique meridians. Results : The older group demonstrated much greater dynamic SVV errors (e.g., 3.4° for the control condition) than the younger group (1.2°, P = 0.002), larger errors with vertical and horizontal astigmatic lenses (older group 4.1°and 5.2° for toric and magnifier lenses vs. younger group 1.2° and 1.4°, respectively, P < 0.001), and a larger influence of the oblique astigmatic lenses (older group 5.6° vs. younger group 2.1°, P

Purpose: The reported signs and symptoms of dry eye (DE) have been discordant. This study evaluated risk factors of DE-related symptoms and signs to explore their association with patient demographics, focusing on the age factor. Methods: The study enrolled 704 consecutive patients visiting general eye clinics who complained of ocular discomfort, but had normal vision. The patients were asked about the presence of six common symptoms related to DE and, tear break-up time (TBUT). The severity of patients&rsquo, keratopathy was also examined, and patients underwent Schirmer&rsquo, s test. Results: Logistic regression analysis demonstrated that younger age (&le, 29 years) was associated with non-visual symptoms and keratopathy, while older age (&ge, 60 years) was associated with short TBUT and low values on Schirmer&rsquo, s test. Middle age was associated with both severe symptoms and signs. Conclusions: Discrepancies in the signs and symptoms of DE may depend, in part, on age, with younger subjects showing severe non-visual symptoms with apparently normal tear function and severe keratopathy, and older subjects showing fewer symptoms and less severe keratopathy despite worse tear function.

Microperimetry, also referred to as fundus perimetry or fundus-driven perimetry, enables simultaneous acquisition of visual sensitivity and eye movement data. We present sensitivity data collected from 60 participants with normal vision using gaze-contingent perimetry. A custom designed spatially dense test grid was used to collect data across the visual field within 13° of fixation. These data are supplemental to a study in which we demonstrated a spatial interpolation method that facilitates comparison of acquired data from any set of spatial locations to normative data and thus screening of individuals with both normal and non-foveal fixation “Methods for normative data comparison in gaze-contigent microperimetry” (Denniss and Astle, 2016) [1].

Purpose It is desirable to make VEP-based acuity estimates match standard subjective acuity numerically, as the latter is familiar to ophthalmologists and optometrists. This is achieved by applying an empirical conversion factor, and previous studies found the resulting values to be within ±1 octave of subjective acuity. This leaves room for improvement. In the present study, we tested for the case of a monocular acuity deficit whether the known difference between subjective and objective acuity in the trusted fellow eye can be used to get a more precise objective estimate in the eye of which the acuity is to be estimated. In other words, we tested whether it would make sense to determine a patient-specific conversion factor. Methods In 19 subjects, we obtained monocular objective and subjective acuity estimates with both eyes. Normal vision and artificially degraded vision were tested. Subjective acuity was taken as the veridical value. We computed the differences between objective and subjective acuity and reasoned that if these were correlated between eyes and acuity levels, the valid information from the trusted healthy eye could be used to improve the precision of the acuity estimate in the other, potentially impaired, eye. Results The difference between objective and subjective acuity values was neither correlated significantly between eyes, nor was it correlated significantly between acuity levels. Conclusions Knowledge about the discrepancy between objective and subjective acuity values in one eye does not help improving the accuracy of acuity estimates in the other eye. The lack of a significant correlation between eyes even at the same acuity level suggests that a major part of the discrepancies between subjective acuity and VEP-based acuity is not the result of factors that would equally apply to both eyes, such as cortical morphology.

Purpose Suppression in amblyopia may be an unequal form of normal interocular suppression or a distinct pathophysiology. To explore this issue, we examined the orientation tuning and contrast dependence of continuous flash suppression (CFS) in adults with amblyopia and visually normal controls. Methods Nine patients (mean age, 26.9 ± SD 4.7 years) and 11 controls (mean age, 24.8 ± SD 5.3 years) participated. In the CFS paradigm, spatially one-dimensional noise refreshing at 10 Hz was displayed in one eye to induce suppression of the other eye, and suppression strength was measured by using a grating contrast increment detection task. In experiment 1, noise contrast was fixed and the orientation difference between the noise and the grating was varied. In experiment 2, noise and grating orientations were identical and noise contrast was varied. Results Suppression patterns varied in both groups. In experiment 1, controls showed consistently orientation-tuned CFS (mean half-height bandwidth, 35.8° ± SD 21.5°) with near-equal strength between eyes. Five of nine patients with amblyopia exhibited orientation-independent CFS. Eight patients had markedly unequal suppression between eyes. Experiment 2 found that increasing the noise contrast to the amblyopic eye may produce suppression of the fellow eye, but suppression remained unequal between eyes. Conclusions Our data revealed that orientation specificity in CFS was very broad or absent in some patients with amblyopia, which could not be predicted by clinical measures. Suppression was unbalanced across the entire contrast range for most patients. This suggests that abnormal early visual experience disrupts the development of interocular suppression mechanisms.

M61, RH, lorry driver, lives with wife, ex smoker (stopped 5 years ago), no other significant PMH, presents with 1 year hx gradually worsening h/a, behavioural changes and vacant episodes (absent seizures) on a background of a 3 year anosmia, o/e mild cognitive impairment and short term memory deficit, anosmia, normal vision and fundoscopy

PurposeTo assess age-related differences in baseline measures of reading performance obtained from the RADNER Reading Charts in healthy eyes with best corrected (ETDRS) distance acuity.MethodsCross-sectional study of participants (n=200) aged 25–74 years (n=20 per 5 years age group). Best corrected distance visual acuity was measured monocularly with ETDRS 2000 Charts. Reading performance was evaluated binocularly with the RADNER Reading Charts. Reading acuity (RA), reading acuity score (RA score), mean reading speed (MEAN-RS), maximum reading speed, reading speed with a long paragraph, critical print size (CPS) and the logMAR/logRAD ratio were analysed.ResultsRA, RA score, CPS-1 (last logRAD with normal reading speed) and ETDRS acuity did not change significantly between age 25 and 54 years. Overall, the mean RA was −0.091±0.07 logRAD, and the RA score was −0.069±0.07 logRAD. The mean difference between the RA and best ETDRS acuity was 0.0603±0.055 logMAR (r=0.62; pConclusionBest corrected RA, reading speed and ETDRS distance acuity were constant until the age of 54 years. An age-related break point was found between the groups aged 50–54 years and 55–59 years; for reading speed, the break point can be assumed to be within the age range of 50–54 years.

Lightly touching a stable reference is associated with sway reduction during standing. Unexpected displacement of the touch reference results in a false-positive balance reaction in some participants, but only with the first such disturbance. This study investigated whether light touch reduces standing sway (1) after the touch reference becomes unreliable, and (2) when participants are aware the touch reference is unreliable. 40 healthy adults, 20 that were naive to the possibility of a touch reference displacement and 20 that were made aware prior to testing, were asked to stand while lightly touching (

BackgroundMicrobial keratitis (MK) is a frequent cause of sight loss in sub-Saharan Africa. However, no studies have formally measured its impact on quality of life (QoL) in this context.MethodsAs part of a nested case–control design for risk factors of MK, we recruited patients presenting with MK at two eye units in Southern Uganda between December 2016 and March 2018 and unaffected individuals, individually matched for sex, age and location. QoL was measured using WHO Health-Related and Vision-Related QoL tools (at presentation and 3 months after start of treatment in cases). Mean QoL scores for both groups were compared. Factors associated with QoL among the cases were analysed in a linear regression model.Results215 case-controls pairs were enrolled. The presentation QoL scores for the cases ranged from 20 to 65 points. The lowest QoL was visual symptom domain; mean 20.7 (95% CI 18.8 to 22.7) and the highest was psychosocial domain; mean 65.6 (95% CI 62.5 to 68.8). At 3 months, QoL scores for the patients ranged from 80 to 90 points while scores for the controls ranged from 90 to 100. The mean QoL scores of the cases were lower than controls across all domains. Determinants of QoL among the cases at 3 months included visual acuity at 3 months and history of eye loss.ConclusionMK severely reduces QoL in the acute phase. With treatment and healing, QoL subsequently improves. Despite this improvement, QoL of someone affected by MK (even with normal vision) remains lower than unaffected controls.

Background: Recent developments in vision restoration include visual prostheses designed to electrically stimulate artificial vision in those who have lost their sight. Major efforts in this area include multi-electrode arrays surgically implanted at various placement areas throughout the visual pathway. Visual prosthetic devices are named according to these placement areas (cortical, optic nerve, sub-retinal and epiretinal). These devices attempt to restore sight for retinal degenerative diseases such as Retinitis Pigmentosa (RP) and Age-related Macular Degeneration (AMD). Aim: To summarise the emerging technologies in the development of artificial ocular devices. Methods: The search methodology comprised seven databases for articles published between January 2000 and March 2017. Outcome data were analysed descriptively with results summarised in a Microsoft Excel database. Both quantitative and qualitative methodologies were used, and the main findings are discussed in a narrative format. Results: Eighty-nine full-text articles were included in this systematic review. Conclusion: The primary goal of these artificial devices is to provide functional vision in order to perform normal daily activities. Even though recent clinical trials in certain countries have shown advances in the development of various vision-restoring devices, they do not produce the same experience for the majority of patients and are unable to completely restore normal vision. The most common type of device according to its placement is the epiretinal device which is also the most successful device as determined in the majority of clinical trials.

PurposeTo examine the intraobserver repeatability of foveal outer nuclear layer (ONL) thickness measurements and evaluate interocular symmetry for patients with achromatopsia (ACHM) and controls.DesignCross-sectional study.SubjectsSixty-four patients withCNGA3- orCNGB3-associated ACHM and 38 patients with normal vision were recruited for analysis.MethodsHorizontal line scans through the fovea of each eye were acquired using optical coherence tomography. Three foveal ONL thickness measurements were made by a single observer using custom software to analyze repeatability. Interocular symmetry was assessed using the average of the three measurements for each eye.Main Outcome MeasuresThe main parameter being measured is foveal ONL thickness.ResultsMean (± SD) foveal ONL thickness for ACHM patients was 74.86 ± 17.82μm (OD) and 75.30 ± 15.68μm (OS) compared to 110.60 ± 15.67μm (OD) and 110.53 ± 13.91μm (OS) for controls. Foveal ONL thickness did not differ between eyes for ACHM (p = 0.821) or control patients (p = 0.961). Intraobserver repeatability was high for foveal ONL measurements in ACHM patients (ICC = 0.939, OD and 0.915, OS) and controls (ICC = 0.991, OD and 0.984, OS).ConclusionsFoveal ONL thickness can be measured with excellent repeatability. While foveal ONL thickness is reduced in ACHM compared to controls, the high interocular symmetry indicates that contralateral ONL measurements could be used as a negative control in early-phase monocular treatment trials.

Keeping the integrity and transparency of the cornea is the most important issue to ensure normal vision. There are more than 10 million patients going blind due to the cornea diseases worldwide. One of the effective ways to cure corneal diseases is corneal transplantation. Currently, donations are the main source of corneas for transplantation, but immune rejection and a shortage of donor corneas are still serious problems. Graft rejection could cause transplanted cornea opacity to fail. Therefore, bioengineer-based corneas become a new source for corneal transplantation. Limbal stem cells (LSCs) are located at the basal layer in the epithelial palisades of Vogt, which serve a homeostatic function for the cornea epithelium and repair the damaged cornea. LSC-based transplantation is one of the hot topics currently. Clinical data showed that the ratio of LSCs to total candidate cells for a transplantation has a significant impact on the effectiveness of the transplantation. It indicates that it is very important to accurately identify the LSCs. To date, several putative biomarkers of LSCs have been widely reported, whereas their specificity is controversial. As reported, the identification of LSCs is based on the characteristics of stem cells, such as a nuclear-to-cytoplasm ratio (N/C) ≥ 0.7, label-retaining, and side population (SP) phenotype. Here, we review recently published data to provide an insight into the circumstances in the study of LSC biomarkers. The particularities of limbus anatomy and histochemistry, the limits of the current technology level for LSC isolation, the heterogeneity of LSCs and the influence of enzyme digestion are discussed. Practical approaches are proposed in order to overcome the difficulties in basic and applied research for LSC-specific biomarkers.

Indoor wayfinding is a major challenge for people with visual impairments, who are often unable to see visual cues such as informational signs, land-marks and structural features that people with normal vision rely on for wayfinding. We describe a novel indoor localization approach to facilitate wayfinding that uses a smartphone to combine computer vision and a dead reckoning technique known as visual-inertial odometry (VIO). The approach uses sign recognition to estimate the user's location on the map whenever a known sign is recognized, and VIO to track the user's movements when no sign is visible. The ad-vantages of our approach are (a) that it runs on a standard smartphone and re-quires no new physical infrastructure, just a digital 2D map of the indoor environment that includes the locations of signs in it; and (b) it allows the user to walk freely without having to actively search for signs with the smartphone (which is challenging for people with severe visual impairments). We report a formative study with four blind users demonstrating the feasibility of the approach and suggesting areas for future improvement.

Eye movements of glaucoma patients have been shown to differ from age-similar control groups when performing everyday tasks, such as reading (Burton et al., 2012; Smith et al., 2014) [1,2], visual search (Smith et al., 2012) [3], face recognition (Glen et al., 2013) [4], driving, and viewing static images (Smith et al., 2012) [5]. Described here is the dataset from a recent publication in which we compared the eye-movements of 44 glaucoma patients and 32 age-similar controls, while they watched a series of short video clips taken from television programs (Crabb et al., 2018) [6]. Gaze was recorded at 1000 Hz using a remote eye-tracker. We also provide demographic information and results from a clinical examination of vision for each participant. Keywords: Eye movements, Scanpaths, Visual fields, Glaucoma, Eye tracking

blindBike is a system that uses multiple sensors including a smartphone camera, gyroscope, gps sensors and a cadence sensor to assist in the process of bicycle driving and navigation for people with low vision. We propose that with the assistance of blindBike it may be possible for those with low vision to be mobile at a new level. However, blindBike can also be assistive to those with normal vision. Through the use of today’s smartphones, the blindBike app can affordably assist with navigation and Road Following. This work focuses on the road following and intersection assistance modules.

Objectives To quantify the annual excess direct medical costs of vision impairment from the perspective of the Bureau of National Health Insurance in Taiwan and to examine whether the costs vary by severity and duration of vision impairment. Methods A retrospective matched cohort analysis was conducted by using data from the Longitudinal Health Insurance Databases between January 1, 2000, and December 31, 2008. All patients newly diagnosed with vision impairment were categorized as having moderate vision loss, severe vision loss, or blindness. Each patient with vision impairment was matched to one randomly selected patient with normal vision by age (±1 year) and sex. At each level of vision impairment, generalized linear models were used to quantify the total annual excess costs and component costs incurred in the first and second years. Results Vision impairment was associated with significantly higher crude excess medical costs. At each level of vision impairment, the total crude medical costs were attributable to different resource utilization and dominated by non–eye-related medical care. After adjusting for covariates, the first-year annual excess costs increased with escalating severity of vision impairment: New Taiwan (NT) $9894 for moderate vision loss, NT $22,760 for severe vision loss, and NT $52,687 for blindness. Similarly, the second-year adjusted costs were estimated as NT $3477, NT $19,532, and NT $28,272 for moderate vision loss, severe vision loss, and blindness, respectively. Conclusions Consistent with Western countries, vision impairment is associated with significantly increased health care costs in Taiwan. The excess costs seem to increase with severity of vision impairment and decrease in the second year.

SIGNIFICANCE: In general, young adults with normal vision show the best visual search performance when compared to children and older adults. Through our study we show that this trend is not observed in individuals with vision impairment. An interaction effect of vision impairment with visual development and aging is observed. PURPOSE: Performance in many visual tasks typically shows improvement with age until young adulthood and then declines with aging. Using a visual search task, this study investigated whether a similar age effect on performance is present in people with central vision loss. METHODS: A total of 98 participants, 37 with normal sight (NS) and 61 with visual impairment (VI) searched for targets in 150 real world digital images. Search performance was quantified by an integrated measure combining speed and accuracy. Participant ages ranged from 5 to 74 years, visual acuity (VA) from −0.14 (20/14.5) to 1.16 logMAR (20/290), and log contrast sensitivity (CS) from 0.48 to 2.0. Data analysis was performed with participants divided into 3 age groups: children (aged45, n=26). RESULTS: Regression (r(2)=0.7) revealed CS (p

The amplitudes of the P100 and N150 early components of evoked potentials in the visual cortex have been analyzed on 33 volunteers with normal vision during matching between the current orientation and that stored in memory. An increase in the P100 response in the occipital and parietal cortical areas was identified as an informative indicator of mismatch between the current and stored-in-memory orientations. This effect was not found for more complex stimuli, namely, spatial patterns. The N150 component demonstrated a similar effect, but in contrast to P100 it was not stimulus specific. Thus, in the first 100 ms, a signal of mismatch between the current and stored-in-memory orientations arises in the early visual areas that represents a mechanism for early implicit response to changes in the basic characteristics of the visual space.

This paper aimed to investigate the accessibility problems encountered by visually disabled and mainstream users on websites and native applications using mobile devices. A total of 10 participants, consisting of 6 blind users and 4 mainstream users took part in this study. A sample of 4 websites and their respective 4 native applications from commercial and governmental organizations were selected and evaluated by means of usability tests. The evaluation resulted in a total of 514 problems encountered, being 409 by blind users and 105 by normal-vision users. The most frequent and most severe problems encountered by blind users on the mobile applications and websites are detailed and compared to the impact they had on mainstream users. The results show initial evidence of critical problems that need to be addressed in the development of mobile applications and websites. Further, they point out to the need of performing more in-depth investigation of accessibility problems encountered by users with visual disabilities to establish effective recommendations to designers. The paper also showed that blind users were more severely impacted by problems in such devices than normal-vision users.

In order to evaluate the effect of the parafoveal area of the retina on smooth pursuit, we compared the horizontal smooth pursuit of visible and amodally completed stimuli in people with central vision loss and controls. In the amodally completed stimuli, a black mask covered the bottom vertex of a moving diamond which is the feature whose movement participants had to track. Both the visible and the amodally completed stimuli moved along regular and irregular sinusoidal motion paths. Our results show that people with central vision loss are able to track a perceptually completed moving stimulus albeit with lower gain, larger tracking errors, and more saccadic eye movements than people with normal vision. Just as the controls, however, people with central vision do better in the no mask condition showing that visual feedback from eccentric vision can improve performance.

More than 100 million people in the United States of America alone suffer from age-related presbyopia caused by a loss of focal accommodation of the eye crystalline lens as the lens stiffens with age. The resulting accommodative error or lag produces blurred images of objects placed at different distances. Conventional fixed uniform or graded power eyeglasses cannot provide accommodation thus resulting in significant visual impairment. In this paper we will discuss the implementation of lightweight auto-focusing eyeglasses that augment the accommodative range thus partially or fully restoring normal vision function. The paper discusses some aspects of the construction of tunable power eyepieces and the implementation of accommodation correction algorithms.

Degrading vision by one eye during a developmental critical period yields enduring deficits in both eye dominance and visual acuity. A predominant model is that ‘reactivating’ ocular dominance (OD) plasticity after the critical period is required to improve acuity in amblyopic adults. However, here we demonstrate that plasticity of eye dominance and acuity are independent, and restricted by the nogo-66 receptor (ngr1) in distinct neuronal populations. Ngr1 mutant mice display greater excitatory synaptic input onto both inhibitory and excitatory neurons with restoration of normal vision. Deleting ngr1 in excitatory cortical neurons permits recovery of eye dominance but not acuity. Reciprocally, deleting ngr1 in thalamus is insufficient to rectify eye dominance but yields improvement of acuity to normal. Abolishing ngr1 expression in adult mice also promotes recovery of acuity. Together, these findings challenge the notion that mechanisms for OD plasticity contribute to the alterations in circuitry that restore acuity in amblyopia.

In a series of experiments, we tested the hypothesis that severely degraded viewing conditions during locomotion distort the perception of distance traveled. Some research suggests that there is little-to-no systematic error in perceiving closer distances from a static viewpoint with severely degraded acuity and contrast sensitivity (which we will refer to as blur). However, several related areas of research-extending across domains of perception, attention, and spatial learning-suggest that degraded acuity and contrast sensitivity would affect estimates of distance traveled during locomotion. In a first experiment, we measured estimations of distance traveled in a real-world locomotion task and found that distances were overestimated with blur compared to normal vision using two measures: verbal reports and visual matching (Experiments 1 a, b, and c). In Experiment 2, participants indicated their estimate of the length of a previously traveled path by actively walking an equivalent distance in a viewing condition that either matched their initial path (e.g., blur/blur) or did not match (e.g., blur/normal). Overestimation in blur was found only when participants learned the path in blur and made estimates in normal vision (not in matched blur learning/judgment trials), further suggesting a reliance on dynamic visual information in estimates of distance traveled. In Experiment 3, we found evidence that perception of speed is similarly affected by the blur vision condition, showing an overestimation in perception of speed experienced in wheelchair locomotion during blur compared to normal vision. Taken together, our results demonstrate that severely degraded acuity and contrast sensitivity may increase people's tendency to overestimate perception of distance traveled, perhaps because of an increased perception of speed of self-motion.

Tablets are increasingly being used in schools for a variety of handwriting tasks. Given that the control of handwriting relies on both visual and proprioceptive feedback, especially in younger writers, this raises the question of whether the texture of the tablet surface affects graphomotor execution. A series of recent studies found that when the smoothness of a tablet screen modifies proprioceptive feedback, the impact on graphomotor execution varies according to the level of the writer’s handwriting skills. However, as the writing on the screen remained visible in these studies, participants may have compensated for the decrease in proprioceptive feedback by relying more heavily on visual information. The aim of the present study was therefore to unravel the respective contributions of different types of sensory feedback during handwriting development and, consequently, the compensatory role of visual information when children and adults have to write on a tablet. To this end, we asked second and fifth graders and adult participants to write letters and pseudowords on a plastic board placed on top of a tablet screen. Participants wrote on either the smooth or the granular side of the plastic board (manipulation of surface friction), and with normal vision or behind a shield that hid the hand and handwriting from direct view (manipulation of vision). Kinematic parameters and legibility were recorded to assess handwriting performances. Results revealed a significant interaction between proprioceptive and visual feedback on letter size, pen speed and legibility, regardless of participants’ age. Furthermore, reducing the visual and proprioceptive feedback had a greater effect on the children’s handwriting performances than on those of adults. Overall, the present study provides new insight into the contribution of the different types of sensory feedback and their interaction with handwriting development. In addition, our results on the impact of tablet surface on graphomotor execution will serve as useful pointers for improving the design of this tool for children, such as increasing the degree of friction of the screen surface.

Increasing popularity of virtual reality (VR) gaming is causing increased concern, as prolonged use induces visual adaptation effects which disturbs normal vision. Effects of VR gaming on accommodation and convergence of young adults by measuring accommodative response and phoria before and after experiencing virtual reality were measured. An increase in accommodative response and a decrease in convergence was observed after immersion in VR games. It was found that visual symptoms were apparent among the subjects post VR exposure.

This paper compares the effects of viewing videos with 2D and 3D displays with regard to the viewing distance (3H vs. 6H, where H is the height of the screen) and viewing time to determine the physical stresses in terms of heart rate variability, galvanic skin resistance (GSR), and performance of the viewer (percent of correct responses). Twenty healthy male university students with a mean age ± standard deviation of 27.7 ± 2.53 years participated in this study as volunteers. None had color blindness, and all had normal vision acuity. Display type by viewing distance interaction had a significant effect on most of the heart rate variability measures and associated with watching time for the GSR responses. The results concluded that viewing the 3D display from a short viewing distance produced significantly high physical stresses compared to viewing the 2D display from the same short viewing distance. However, the 3D display seemed to impart lower physical stress than the 2D display at long viewing distances. The findings of this study indicate that physical stresses appeared significant at close viewing distance after watching a 3D display for 50 min and increased with continued watching time. In addition, viewer performance was higher for the 3D compared to 2D display type.

The purpose of this study was to examine normal vision and eye disease in relation to art. Ophthalmology cannot explain art, but vision is a tool for artists and its normal and abnormal characteristics may influence what an artist can do. The retina codes for contrast, and the impact of this is evident throughout art history from Asian brush painting, to Renaissance chiaroscuro, to Op Art. Art exists, and can portray day or night, only because of the way retina adjusts to light. Color processing is complex, but artists have exploited it to create shimmer (Seurat, Op Art), or to disconnect color from form (fauvists, expressionists, Andy Warhol). It is hazardous to diagnose eye disease from an artist's work, because artists have license to create as they wish. El Greco was not astigmatic; Monet was not myopic; Turner did not have cataracts. But when eye disease is documented, the effects can be analyzed. Color-blind artists limit their palette to ambers and blues, and avoid greens. Dense brown cataracts destroy color distinctions, and Monet's late canvases (before surgery) showed strange and intense uses of color. Degas had failing vision for 40 years, and his pastels grew coarser and coarser. He may have continued working because his blurred vision smoothed over the rough work. This paper can barely touch upon the complexity of either vision or art. However, it demonstrates some ways in which understanding vision and eye disease give insight into art, and thereby an appreciation of both art and ophthalmology.

Although the neural locus of strabismic amblyopia has been shown to lie at the first site of binocular integration, first in cat and then in primate, an adequate mechanism is still lacking. Here we hypothesise that increased temporal dispersion of LGN X-cell afferents driven by the deviating eye onto single cortical neurons may provide a neural mechanism for strabismic amblyopia. This idea was investigated via single cell extracellular recordings of 93 X and 50 Y type LGN neurons from strabismic and normal cats. Both X and Y neurons driven by the non-deviating eye showed shorter latencies than those driven by either the strabismic or normal eyes. Also the mean latency difference between X and Y neurons was much greater for the strabismic cells compared with the other two groups. The incidence of lagged X-cells driven by the deviating eye of the strabismic cats was higher than that of LGN X-cells from normal animals. Remarkably, none of the cells recorded from the laminae driven by the non-deviating eye were of the lagged class. A simple computational model was constructed in which a mixture of lagged and non-lagged afferents converge on to single cortical neurons. Model cut-off spatial frequencies to a moving grating stimulus were sensitive to the temporal dispersion of the geniculate afferents. Thus strabismic amblyopia could be viewed as a lack of developmental tuning of geniculate lags for neurons driven by the amblyopic eye. Monocular control of fixation by the non-deviating eye is associated with reduced incidence of lagged neurons, suggesting that in normal vision, lagged neurons might play a role in maintaining binocular connections for cortical neurons.

Purpose: to define and to compare separate indicators of a functional condition of touch systems of pupils of middle classes with visual impairment and their contemporaries with normal vision. Materials and Methods : pupils of middle classes with visual impairment and pupils of middle classes with normal vision took part in the research. During the research such methods were applied: analysis and synthesis of references, perimetry, determination of visual acuity by means of a special table, acumetry, esthesiometry, determination of resistance of a vestibular mechanism to rotary loadings, methods of mathematical statistics. Results: the analysis of separate indicators of a functional condition of visual, acoustical, vestibular and tactile analyzers of pupils with visual impairment and without them is carried out. Conclusions: it is established that the studied indicators of a functional condition of touch systems at pupils of middle classes with visual impairment are better, than at their contemporaries with normal vision

Purpose This study aimed to develop and validate a new Chinese reading chart for children. The characteristics of reading profiles among Hong Kong children were also investigated. Methods A new reading chart was developed using the design principles of the MNREAD chart. Children (N = 169) aged seven to 11 years with normal vision and no developmental or reading difficulties were recruited from four local Hong Kong primary schools located in four different districts. Reading performance was measured using three versions of the new Chinese reading chart for children as well as six short passages. Repeated reading measures were conducted for 79 participants 4–8 weeks later. A linear mixed-model analysis was performed for the reading measures to identify the contribution of each source of variation (individual participant, among-charts within-session and between-sessions, and error) to the total variance. Results Three reading parameters were derived from the Chinese reading chart for children – maximum reading speed (MRS), critical print size (CPS) and reading acuity (RA). Results from the linear mixed-model and Bland and Altman analyses revealed that all three versions of the chart were reproducible, with little variability among-charts and between-sessions (p

We have studied the effects of normal aging on visual perception and the existence of possible compensatory brain mechanisms. Were measured in three groups of 30 people with normal vision and average age of 19.6, 42.6 and 65.7 years, the response time to the presentation of stimuli (0.5º in diameter grey circles) sequentially in 24 positions of the visual field, distributed in 8 polar coordinates and 3 eccentricities (2.15, 3.83 and 5.53 degrees of visual field). The stimulus was presented for 100 milliseconds, with low and high contrast (6% and 78%, respectively). The experiments were conducted with and without covert attention to stimuli. With age was observed a progressive increase in the response times from the stimuli of 6% of contrast and those presented in the eccentricity of 5.53º. With covert attention, response times were significantly reduced in the three age groups. However, while the younger and older showed similar reductions in the response times, the adult group obtained minor cuts. These results show that during aging occurs a selective and progressive deterioration in the perception of low contrast and that this deterioration is greater in the peripheral macular areas and that from sixty years the visual attention compensating mechanisms have greater efficiency in the improvement of visual perception.

We have studied the effects of normal aging on visual perception and the existence of possible compensatory brain mechanisms. Were measured in three groups of 30 people with normal vision and average age of 19.6, 42.6 and 65.7 years, the response time to the presentation of stimuli (0.5o in diameter grey circles) sequentially in 24 positions of the visual field, distributed in 8 polar coordinates and 3 eccentricities (2.15, 3.83 and 5.53 degrees of visual field). The stimulus was presented for 100 milliseconds, with low and high contrast (6% and 78%, respectively). The experiments were conducted with and without covert attention to stimuli. With age was observed a progressive increase in the response times from the stimuli of 6% of contrast and those presented in the eccentricity of 5.53o. With covert attention, response times were significantly reduced in the three age groups. However, while the younger and older showed similar reductions in the response times, the adult group obtained minor cuts. These results show that during aging occurs a selective and progressive deterioration in the perception of low contrast and that this deterioration is greater in the peripheral macular areas and that from sixty years the visual attention compensating mechanisms have greater efficiency in the improvement of visual perception.

The ability to navigate without getting lost is an important aspect of quality of life. In 5 studies, we evaluated how spatial learning is affected by the increased demands of keeping oneself safe while walking with degraded vision (mobility monitoring). We proposed that safe low vision mobility requires attentional resources, providing competition for those needed to learn a new environment. In Experiments 1 and 2, participants navigated along paths in a real-world indoor environment with simulated degraded vision or normal vision. Memory for object locations seen along the paths was better with normal compared with degraded vision. With degraded vision, memory was better when participants were guided by an experimenter (low monitoring demands) versus unguided (high monitoring demands). In Experiments 3 and 4, participants walked while performing an auditory task. Auditory task performance was superior with normal compared with degraded vision. With degraded vision, auditory task performance was better when guided compared with unguided. In Experiment 5, participants performed both the spatial learning and auditory tasks under degraded vision. Results showed that attention mediates the relationship between mobility-monitoring demands and spatial learning. These studies suggest that more attention is required and spatial learning is impaired when navigating with degraded viewing.

The ability to safely perform cognitive-motor dual-tasks is critical for independence of older adults. We compared age-associated differences in global and segmental control during dual-task walking in sub-optimal sensory conditions. Thirteen young (YA) and 13 healthy older (OA) adults walked a straight pathway with cognitive dual-task of walking-while-talking (WT) or no-WT under four sensory conditions. On randomly selected trials, visual and vestibular inputs were manipulated using blurring goggles (BV) and Galvanic Vestibular Stimulation (GVS), respectively. Gait speed decreased more in YA than OA during WT. Gait speed increased with GVS with normal vision but not BV. Step length considerably decreased with WT. Trunk roll significantly decreased only in OA with GVS in WT. Head roll significantly decreased with GVS regardless of age. Results indicate GVS-induced adaptations were dependent on available visual information. YA reduced their gait speed more than OA to achieve a similar pace to safely perform WT. GVS resulted in both age-groups to reduce head movement. However, with the addition of WT during GVS, OA also stiffened their trunk. Therefore, with increased attentional demands healthy OA employed different compensatory strategies than YA to maintain postural control.

Tourette syndrome (TS) is a childhood-onset developmental disorder characterized by involuntary motor and vocal tics. Previous studies have indicated that children with TS demonstrate postural control anomalies when standing. The aim of this study was to compare postural stability under normal and altered sensory conditions in children with TS and healthy control (HC) children. A convenience sample of twelve children with TS (9 boys and 3 girls; 9.4 ± 1.1 yr) and 12 HC age- and gender-matched children (9.2 ± 1.1 yr) participated in this study. The Sensory Organization Test (SOT) was used to assess postural stability under six altered sensory conditions (1. normal vision, fixed support; 2. eyes closed, fixed support; 3. vision sway-referenced, fixed support; 4. normal vision, support sway-referenced; 5. eyes closed, support surface sway-referenced; 6. both vision and support surface sway-referenced) using the SMART Balance Master® 8.2 (NeuroCom® International, Inc, Clackamas, OR, USA). The results showed significant differences between the two groups in conditions 5 and 6 (p=0.003 and 0.002, respectively). The mean composite equilibrium score in children with TS was significantly lower than that of HC children (p0.000). The results suggested that children with TS had greater difficulty in maintaining postural stability, especially when vestibular information was challenged. The results of this study provide supporting evidence for possible deficits in impaired access to vestibular information and sensorimotor integration of postural control in children with TS.

BACKGROUND: Visual acuity is the resolving power of eyes which enables to distinguish the details and shapes of the objects. It is influenced by the intensity (illumination) of light falling on the object. Measuring visual acuity is a simple test in assessing-health of the eyes, the pathway and visual brain. Intact normal vision is mandatory for selection of posts related to driving and traffic services. Intactness of visual acuity is influenced by a number of factors and one among them is intensity of ambient light. Hence, this study is undertaken to assess optimum light intensity for better visual perception. AIM: To evaluate the association between visual acuity and intensity of light and the optimum intensity of light to carry out for better perception of vision. MATERIALS AND METHODS: 100 literate subjects 50 males and 50 females between 15-45 years, act both as cases and controls. Subjects, instructed to read alphabets and numbers from Snellen chart in 15 watts, 20 watts, 40 watts, 60 watts, 100 watts, 200 watts were considered as the study group and the same subjects in this study in day light as controls. Chart was placed at 6m distance. Both right and left eyes were tested separately in dark room illuminated with controlled light intensities. Number of correct characters read were noted for different illuminations and compared with that of controls. RESULTS: Reduced illumination significantly increased the no of incorrect choices and was statistically significant (P < 0.05) between 15 100 W. Visual acuity was best in 200 W in comparison with day light but was not statistically significant. However Visual acuity showed no significant difference between males and females for different intensities of light.

PURPOSE To determine whether pre-operative electroretinography (ERG) predicts postoperative vision in dogs undergoing retinal reattachment surgery (RRS). METHODS This 18-month prospective study recorded signalment, duration, cause, and extent of retinal detachment and pre-operative vision status. Rod and mixed rod-cone ERG responses were recorded prior to RRS. Referring veterinary ophthalmologists assessed vision 2 months postoperatively. RESULTS Thirty dogs (40 affected eyes) aged 4 months to 12.1 years were included. The detachment extent was 150° -320° in 15 of 40 eyes, 360° in 24 of 40 eyes, and not recorded in one eye. Most dogs had a genetic predisposition for retinal detachment. Eight eyes of seven dogs had previous cataract surgery. Mean estimated duration of detachment prior to surgery was 24.5 ± 19.6 days. Pre-operatively, 34 of 40 eyes were blind, two of 40 eyes were sighted, and four of 40 eyes had severely diminished vision. Compared to normative ERG values in our clinics, pre-operative ERGs were classified as "normal" in five of 40 eyes, "attenuated" in seven of 40 eyes, and "flat" in 28 of 40 eyes. Following RRS, the retina was fully reattached in all operated eyes. Two-month postoperatively, 30 of 40 eyes had "normal" vision as defined by referring veterinary ophthalmologists, six of 40 eyes had "limited" or "diminished" vision and four of 40 eyes were blind. Normal vision was regained in 12 of 12 (100%) of eyes with normal or attenuated pre-operative ERG's, but only in 18 of 28 (64%) of eyes with flat pre-operative ERG 's (Linear-by-linear test, P = 0.029). CONCLUSIONS A recordable pre-operative ERG, even if attenuated, is associated with return of vision in canine RRS patients, and is a favorable prognostic indicator.

Purpose If you cannot follow the story when watching a video, then the viewing experience is degraded. We measured the difficulty of following the story, defined as the ability to acquire visual information, which is experienced by people with homonymous hemianopia (HH). Further, we proposed and tested a novel rehabilitation aid. Methods Participants watched 30-second directed video clips. Following each video clip, subjects described the visual content of the clip. An objective score of information acquisition (IA) was derived by comparing each new response to a control database of descriptions of the same clip using natural language processing. Study 1 compared 60 participants with normal vision (NV) to 24 participants with HH to test the hypothesis that participants with HH would score lower than NV participants, consistent with reports from people with HH that describe difficulties in video watching. In the second study, 21 participants with HH viewed clips with or without a superimposed dynamic cue that we called a content guide. We hypothesized that IA scores would increase using this content guide. Results The HH group had a significantly lower IA score, with an average of 2.8, compared with 4.3 shared words of the NV group (mixed-effects regression, P < 0.001). Presence of the content guide significantly increased the IA score by 0.5 shared words (P = 0.03). Conclusions Participants with HH had more difficulty acquiring information from a video, which was objectively demonstrated (reduced IA score). The content guide improved information acquisition, but not to the level of people with NV. Translational Relevance The value as a possible rehabilitation aid of the content guide warrants further study that involves an extended period of content-guide use and a randomized controlled trial.

Red eye is a common ocular presentation in primary care, and there are several challenges that healthcare practitioners may encounter when caring for such patients. The main ocular conditions that can give rise to red eye are: primary acute angle closure glaucoma, acute iritis, dry eye, blepharitis and conjunctivitis. Red eye can be classified as sight-threatening or non-sight-threatening. Many patients presenting with painless red eye and normal vision usually recover well. However, when red eye is associated with pain, photophobia, watering and blurred vision, it is potentially sight-threatening and must be addressed urgently. Therefore, it is vital for healthcare practitioners to be able to undertake a careful assessment of the patient and make an accurate diagnosis early. This article provides an overview of the common causes of red eye encountered in general practice or an eye clinic. It discusses the nurse's role in the care and management of patients with red eye, with reference to patient assessment, the skills required to make an accurate diagnosis, treatment and health promotion.

Object Postoperative visual outcomes following elective repair of unruptured paraclinoid aneurysms (UPAs) are not well defined. The objective of this study was to investigate the influence of treatment modality on visual function. Methods A systematic literature analysis using the Ovid Medline and EMBASE electronic databases was performed, encompassing all English language studies (published between 1996 and 2016) reporting visual, clinical, and angiographic treatment outcomes for UPAs. Rates of visual morbidity (any new, permanent postoperative deficit in visual acuity or visual field, or worsening of a preoperative deficit), angiographic (recurrence, retreatment) and clinical outcomes (death and dependency, post-treatment subarachnoid hemorrhage (SAH)) were extracted and analyzed. Random effects meta-analysis was performed for comparative studies. Results Twenty-eight studies reported on postoperative visual outcomes, with data available for 1013 endovascular and 691 microsurgical patients. In patients with normal vision undergoing repairs for UPAs, rates of postoperative visual morbidity were higher following microsurgical (10.8%; 95% CI 8.5–13.7) than endovascular (2.0%; 95% CI 1.2–3.2) interventions, p Conclusions In patients with normal vision undergoing repairs for UPAs, there is a positive correlation between visual outcomes and endovascular treatments. When visual compromise is present, surgery provided modest advantage in visual recovery. However, definitive conclusions were not possible due to data heterogeneity. Disclosures M. Asaid: None. A. O’Neill: None. D. Bervini: None. R. Chandra: None. L. Lai: None.