Measuring spatial visual loss in rats by retinotopic mapping of the superior colliculus using a novel multi-electrode array technique

BACKGROUND

The retinotopic map property of the superior colliculus (SC) is a reliable indicator of visual functional changes in rodents. Electrophysiological mapping of the SC using a single electrode has been employed for measuring visual function in rat and mouse disease models. Single electrode mapping is highly laborious requiring long-term exposure to the SC surface and prolonged anesthetic conditions that can adversely affect the mapping data.

NEW METHOD

To avoid the above-mentioned issues, we fabricated a fifty-six (56) electrode multi-electrode array (MEA) for rapid and reliable visual functional mapping of the SC. Since SC is a dome-shaped structure, the array was made of electrodes with dissimilar tip lengths to enable simultaneous and uniform penetration of the SC.

RESULTS

SC mapping using the new MEA was conducted in retinal degenerate (RD) Royal College of Surgeons (RCS) rats and rats with focal retinal damage induced by green diode laser. For SC mapping, the MEA was advanced into the SC surface and the visual activities were recorded during full-filed light stimulation of the eye. Based on the morphological examination, the MEA electrodes covered most of the exposed SC area and penetrated the SC surface at a relatively uniform depth. MEA mapping in RCS rats (n=9) demonstrated progressive development of a scotoma in the SC that corresponded to the degree of photoreceptor loss. MEA mapping in the laser damaged rats demonstrated the presence of a scotoma in the SC area that corresponded to the location of retinal laser injury.

COMPARISON WITH EXISTING METHODS AND CONCLUSIONS

The use of MEA for SC mapping is advantageous over single electrode recording by enabling faster recordings and reducing anesthesia time. This study establishes the feasibility of the MEA technique for rapid and efficient SC mapping, particularly advantageous for evaluating therapeutic effects in retinal degenerate rat disease models.

Assessing fall risk and equilibrium function in patients with age-related macular degeneration and glaucoma: An observational study

BACKGROUND

Falls in older adults are a significant public health concern, and age-related macular degeneration (AMD) and glaucoma have been identified as potential visual risk factors. This study was designed to assess equilibrium function, fall risk, and fall-related self-efficacy (an individual's belief in their capacity to act in ways necessary to reach specific goals) in patients with AMD and glaucoma.

METHODS

This observational study was performed at the Otorhinolaryngology Department of Shinseikai Toyama Hospital. The cohort comprised 60 participants (AMD; n = 30; median age, 76.0 years; and glaucoma; n = 30; median age, 64.5 years). Visual acuity and visual fields were assessed using the decimal best-corrected visual acuity and Humphrey visual field tests, respectively. The evaluation metrics included pathological eye movement analysis, bedside head impulse test, single-leg upright test, eye-tracking test, optokinetic nystagmus, and posturography. Furthermore, we administered questionnaires for fall risk determinants including the Dizziness Handicap Inventory, Activities-Specific Balance Confidence Scale, Falls Efficacy Scale-International, and Hospital Anxiety and Depression Scale. The collected data were analyzed using descriptive statistics, and Spearman's correlation analysis was employed to examine the interrelations among the equilibrium function, fall risk, and other pertinent variables.

RESULTS

Most participants exhibited standard outcomes in equilibrium function evaluations. Visual acuity and field deficits had a minimal impact on subjective dizziness manifestations, degree of disability, and fall-related self-efficacy. Both groups predominantly showed high self-efficacy. No significant correlation was observed between visual acuity or field deficits and body equilibrium function or fall risk. However, greater peripheral visual field impairment was associated with a tendency for sensory reweighting from visual to somatosensory.

CONCLUSION

Self-efficacy was higher and fall risk was relatively lower among patients with mild-to-moderate visual impairment, with a tendency for sensory reweighting from visual to somatosensory in those with greater peripheral visual field impairment. Further studies are required to validate these findings.

Reduced spatial attentional distribution in older adults

Older adults show decline in visual search performance, but the underlying cause remains unclear. It has been suggested that older adults' altered performance may be related to reduced spatial attention to peripheral visual information compared with younger adults. In this study, 18 younger (M = 21.6 years) and 16 older (M = 69.1 years) participants performed pop-out and serial visual search tasks with variously sized gaze-contingent artificial central scotomas (3°, 5°, or 7° diameter). By occluding central vision, we measured how attention to the periphery was contributing to the search performance. We also tested the effect of target eccentricity on search times and eye movements. We hypothesized that, if attention is reduced primarily in the periphery in older adults, we would observe longer search times for more eccentric targets and with central occlusion. During the pop-out search, older adults showed a steeper decline in search performance with increasing eccentricity and central scotoma size compared with younger adults. In contrast, during the serial search, older adults had longer search times than younger adults overall, independent of target eccentricity and scotoma size. Longer search times were attributed to higher cost-per-item slopes, indicating increased difficulty in simultaneously processing complex symbols made up of separable features in aging, possibly stemming from challenges in spatially binding individual features. Altogether, our findings point to fewer attentional resources of simultaneous visual processing to distribute over space or separable features of objects, consistent with decreased dorsal visual stream functioning in aging.

Does the sampling frequency of an eye tracker affect the detection of glaucomatous visual field loss?

PURPOSE

Evidence suggests that eye movements have potential as a tool for detecting glaucomatous visual field defects. This study evaluated the influence of sampling frequency on eye movement parameters in detecting glaucomatous visual field defects during a free-viewing task.

METHODS

We investigated eye movements in two sets of experiments: (a) young adults with and without simulated visual field defects and (b) glaucoma patients and age-matched controls. In Experiment 1, we recruited 30 healthy volunteers. Among these, 10 performed the task with a gaze-contingent superior arcuate (SARC) scotoma, 10 performed the task with a gaze-contingent biarcuate (BARC) scotoma and 10 performed the task without a simulated scotoma (NoSim). The experimental task involved participants freely exploring 100 images, each for 4 s. Eye movements were recorded using the LiveTrack Lightning eye-tracker (500 Hz). In Experiment 2, we recruited 20 glaucoma patients and 16 age-matched controls. All participants underwent similar experimental tasks as in Experiment 1, except only 37 images were shown for exploration. To analyse the effect of sampling frequency, data were downsampled to 250, 120 and 60 Hz. Eye movement parameters, such as the number of fixations, fixation duration, saccadic amplitude and bivariate contour ellipse area (BCEA), were computed across various sampling frequencies.

RESULTS

Two-way ANOVA revealed no significant effects of sampling frequency on fixation duration (simulation, p = 0.37; glaucoma patients, p = 0.95) and BCEA (simulation, p = 0.84; glaucoma patients: p = 0.91). BCEA showed good distinguishability in differentiating groups across different sampling frequencies, whereas fixation duration failed to distinguish between glaucoma patients and controls. Number of fixations and saccade amplitude showed variations with sampling frequency in both simulations and glaucoma patients.

CONCLUSION

In both simulations and glaucoma patients, BCEA consistently differentiated them from controls across various sampling frequencies.

Reduced peripheral vision in glaucoma and boundary extension

CLINICAL RELEVANCE

Peripheral vision is known to be critical for spatial navigation. However, visual cognition, which impacts peripheral vision, has not been studied extensively in glaucoma.

BACKGROUND

Spatial memory was assessed with a known to induce a robust memory distortion called "boundary extension" in which participants erroneously remember seeing more of a scene than was present in the sensory input.

METHODS

Fifteen patients with glaucoma and 15 age-matched normally sighted controls participated in the experiment. Participants were shown 10 photographs of natural scenes randomly displayed for 0.5 s or 10 s. Following each scene, the participant was asked to draw it from memory.

RESULTS

On average, boundary extension was larger, by 12%, for patients than for controls, but the difference was significant for 4 photographs. Patients tended to add more space between the object and the edges than there was between the objects and the border of the photograph. A control experiment in which participants were asked to draw isolated objects without scene context resulted in a significant reduction of the memory distortion in both groups, but patients still drew the objects smaller than controls.

CONCLUSION

The reduced field of view in glaucoma has an impact on spatial memory for scenes and on perception of size.

Higher susceptibility to central crowding in glaucoma

CLINICAL RELEVANCE

Crowding limits many daily life activities, such as reading and the visual search for objects in cluttered environments. Excessive sensitivity to crowding, especially in central vision, may amplify the difficulties of patients with ocular pathologies. It is thus important to investigate what limits visual activities and how to improve it.

BACKGROUND

Numerous studies have reported reduced contrast sensitivity in central vision in patients with glaucoma. However, deficits have also been observed for letter recognition at high contrast, suggesting that contrast alone cannot completely account for impaired central perception.

METHOD

Seventeen patients and fifteen age-matched controls were randomly presented with letters in central or parafoveal vision at 5° eccentricity for 200 ms. They were asked to decide whether the central T was upright or inverted. The T was either presented in isolation (uncrowded) or flanked by two Hs (crowded) at various spacings. Contrast was manipulated: 60% and 5%.

RESULTS

Compared to controls, patients exhibited a significant effect of crowding in central vision, with higher accuracy for the isolated T than for HTH only at low contrast. In parafoveal vision, an effect of crowding was also observed only in patients. The spacing to escape crowding varied as a function of contrast. Larger spacing was required at low contrast than at high contrast. Susceptibility to crowding was related to central visual field defect for central presentations and to contrast sensitivity for parafoveal presentations, only at low contrast. Controls were at ceiling level both for central and parafoveal presentations.

CONCLUSION

Crowding limits visual perception, impeding reading and object recognition in cluttered environments. Visual field defects and lower contrast sensitivity in glaucoma can increase susceptibility to central and parafoveal crowding, the deleterious effect of which can be improved by manipulating contrast and spacing between elements.

Central visual field damage in glaucoma eyes with choroidal microvasculature dropout with and without high axial myopia

PURPOSE

To characterise the relationship between a deep-layer microvasculature dropout (MvD) and central visual field (VF) damage in primary open-angle glaucoma (POAG) patients with and without high axial myopia.

DESIGN

Cross-sectional study.

METHODS

Seventy-one eyes (49 patients) with high axial myopia and POAG and 125 non-highly myopic POAG eyes (97 patients) were enrolled. Presence, area and angular circumference of juxtapapillary MvD were evaluated on optical coherence tomography angiography B-scans and en-face choroidal images.

RESULTS

Juxtapapillary MvD was detected more often in the highly myopic POAG eyes (43 eyes, 86%) than in the non-highly myopic eyes (73 eyes, 61.9%; p=0.002). In eyes with MvD, MvD area and angular circumference (95% CI) were significantly larger in the highly myopic eyes compared with the non-highly myopic eyes (area: (0.69 (0.40, 0.98) mm2 vs 0.31 (0.19, 0.42) mm2, p=0.011) and (angular circumference: 84.3 (62.9, 105.8) vs 74.5 (58.3, 90.9) degrees, p<0.001), respectively. 24-2 VF mean deviation (MD) was significantly worse in eyes with MvD compared with eyes without MvD in both groups (p<0.001). After adjusting for 24-2 MD VF, central VF defects were more frequently found in eyes with MvD compared with eyes without MvD (82.7% vs 60.9%, p<0.001). In multivariable analysis, higher intraocular pressure, worse 24-2 VF MD, longer axial length and greater MvD area and angular circumference were associated with worse 10-2 VF MD.

CONCLUSIONS

MvD was more prevalent and larger in POAG eyes with high myopia than in non-highly myopic POAG eyes. In both groups, eyes with MvD showed worse glaucoma severity and more central VF defects.

Saccadic re-referencing training with gaze-contingent FRL-'fixation': Effects of scotoma type and size adaptation

Foveal vision loss makes the fovea as saccadic reference point maladaptive. Training programs have been proposed that shift the saccadic reference point from the fovea to an extrafoveal location, just outside the area of vision loss. We used a visual search task to train normal-sighted participants to fixate target items with a predetermined 'forced retinal location' (FRL) adjacent to a simulated central scotoma. We found that training was comparatively successful for scotomata that had either a sharp or blurry demarcation from the background. Completing the task with sharp-edged scotoma resulted in overall higher training gains. Training with blurry-edged scotoma, however, yielded overall better results when scotoma size was increased after training and participants needed to adapt to a more eccentric FRL, as may be necessary in patients with progressive degenerative eye diseases.

Outer Retinal Hyperreflective Dots: A Potential Imaging Biomarker in Rhegmatogenous Retinal Detachment

PURPOSE

To investigate hyperreflective dots (HRDs) on baseline OCT in rhegmatogenous retinal detachment (RRD).

DESIGN

Retrospective cohort study.

SUBJECTS

Consecutive primary fovea-off RRDs presenting between January 2012 and September 2022.

METHODS

Visual acuity (VA) was obtained at baseline, 3, 6, and 12 months. Baseline foveal OCT scans were graded for the presence of HRDs in the outer retina, morphologic stage of RRD in the parafovea, and foveal photoreceptor integrity (intact, patchy or complete loss of the bacillary layer). Epiretinal membrane (ERM) and cystoid macular edema (CME) were graded after surgery.

MAIN OUTCOME MEASURES

The primary outcome was the proportion of patients in each morphologic stage with HRDs present on OCT and their association with postoperative VA. Secondary outcomes included association with the height of foveal detachment, duration of central vision loss, RRD extent, and development of ERM/CME.

RESULTS

A total of 351 patients were included. The presence of HRDs by morphologic stage of RRD was 0% in stage 1, 4.5% (2/42) in stage 2, 13% (7/54) in stage 3a, 16% (20/126) in stage 3b, 48% (40/83) in stage 4, and 85% (35/41) in stage 5. Hyperreflective dots were associated with increasing stage of RRD (P < 0.001), reduced integrity of foveal photoreceptors (P < 0.001), and reduced postoperative VA at 3, 6, and 12 months (P < 0.001), after excluding visually significant cataracts and adjusting for covariates. There was also a significant association between HRDs and height of foveal detachment, duration of central vision loss, and RRD extent (P < 0.001). Hyperreflective dots were neither associated with postoperative ERM formation nor with its severity (P = 0.27). Nevertheless, they were associated with the occurrence of CME at 3 and 6 months after surgery (P = 0.01; P = 0.006).

CONCLUSIONS

Hyperreflective dots have been hypothesized to consist of intraretinal inflammatory cells. We found that HRDs were significantly associated with the morphologic stage, extent, duration, and height of the RRD before surgery and with reduced VA and CME after surgery. Our results suggest that HRDs are associated with photoreceptor degeneration, as longstanding and extensive RRDs are more likely to present with HRDs. The association of HRDs with CME provides insight into the possible importance of inflammatory processes in RRD before and after surgery.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Foveal cone loss in tamoxifen maculopathy: a case report

BACKGROUND

Tamoxifen is used in low dose concentrations (20-40 mg per day) as a therapy for breast cancer but is known to have ocular side effects. In this case report, the foveal cone integrity in a tamoxifen-treated patient who complained of a small central scotoma in the left eye while reading was examined using high resolution adaptive optics imaging.

CASE PRESENTATION

Both eyes of a 54-year-old Caucasian, non-hispanic female who had been treated with tamoxifen for 1.5 years were examined using various imaging modalities including fundus photography, fundus autofluorescence, fluorescein angiography, spectral-domain optical coherence tomography, and adaptive optics scanning laser ophthalmoscopy. Clinical spectral-domain optical coherence tomography showed a very small disruption to the photoreceptor layer at the fovea in the left eye only. However, adaptive optics scanning laser ophthalmoscopy imaging revealed foveal cone loss in both eyes, but to a lesser extent in the right eye. Inner retinal changes were not observed in either eye.

CONCLUSION

The area of cone loss was similar in size to a single newsprint letter when projected onto the retina, matching the patient's description of a scotoma in the left eye. Given the isolated loss of foveal cone photoreceptors with the absence of previously reported inner retinal and vascular changes, our results may indicate the earliest retinal changes associated with tamoxifen retinopathy.

The Effect of Varied Microperimetric Biofeedback Training in Central Vision Loss: A Randomized Trial

SIGNIFICANCE

This investigation reports for the first time the effects of different microperimetric biofeedback strategies in visually impaired subjects with central field loss.

PURPOSE

This study aimed to evaluate the effects of two MP-3 microperimeter biofeedback strategies on the visual performance of subjects with central vision loss. Moreover, changes between the groups were compared to provide indications of practice with biofeedback stimulation in subjects with central vision loss.

METHODS

Using simple randomization, 19 participants were trained according to two different biofeedback stimulation approaches using the MP-3 microperimeter. Patients were assigned to two different groups: subjects trained for 2 days a week (group A) and 3 days a week (group B). The patients in each group were randomized to perform a total of 10 or 15 sessions.

RESULTS

Fixation stability increased from 4.5 ± 2.8 to 2.3 ± 2.2° 2 and from 8.2 ± 6.9 to 1.4 ± 1° 2 after 2 and 3 weekly biofeedback training sessions, respectively ( P < .05). Biofeedback training induced a significant improvement of 40.7 and 29.4% in reading speed for groups A and B, respectively ( P < .05). A comparison of two weekly biofeedback training sessions with three weekly biofeedback sessions demonstrated greater fixation stability in group B ( P < .05).

CONCLUSIONS

This study concludes that a biofeedback intervention is effective in enhancing oculomotor control in patients with central vision loss. In our study, a more intensive biofeedback strategy seemed to produce significantly better results in terms of functional vision parameters.

Foveal avascular zone vessel density is associated with visual field progression in early-stage glaucoma eyes with central visual field damage

We investigated the relationship between foveal avascular zone (FAZ)-related parameters, assessed by optical coherence tomography angiography (OCT-A), and visual field (VF) progression in early-stage open-angle glaucoma (OAG) eyes with central visual field (CVF) defects. Early-stage glaucoma eyes [VF mean deviation (MD) ≥ - 6 dB] with CVF defects were included. The rates of longitudinal change in FAZ-related parameters and structural parameters were evaluated and compared between VF progressors and non-progressors, using linear mixed effects models. Cox proportional hazards model and linear regression models were used to identify factors associated with VF progression, the VF MD reduction rate and the change rate of mean total deviation in central 12 VF points (MTD10). A total of 131 eyes were included and VF progression was detected in 32 eyes (24.4%) during 3.45 years of follow-up. The rates of reduction in vessel density in the 300 µm width annular region surrounding the FAZ (FD300) and macular ganglion cell-inner plexiform layer thickness (mGCIPLT) were significantly faster in progressors than in non-progressors. The faster VF MD or MTD10 reduction rates were associated with faster rates of FD300 loss and mGCIPLT reduction. The FD300 reduction rate is significantly associated with VF progression in early-stage OAG eyes with CVF defects. FD300 may be an adjunctive biomarker of VF progression in glaucomatous eyes with CVF defects.

INFLUENCE OF PREOPERATIVE POSTURING ON SUBFOVEAL FLUID HEIGHT IN MACULA-OFF RETINAL DETACHMENTS

PURPOSE

To evaluate the effect of preoperative posturing on subfoveal fluid height (SFFH) in macula-off retinal detachment.

METHODS

A prospective study including patients with macula-off retinal detachment with SFFH measurable on optical coherence tomography (OCT) and duration of loss of central vision (LCV) ≤ 7 days. Linear OCT volume scans were performed at baseline, after 1 minute, 1 hour, 4 hours, and on the next morning. For the first hour, all patients remained in an upright position. Patients were then either instructed to posture until the surgery according to the location of the primary retinal break (posturing group) or were not given any instructions (control group).

RESULTS

Twenty-four patients were included in the posturing group and 11 patients in the control group. There was no significant change in SFFH between baseline, 1 minute, 1 hour, and 4 hours. The mean SFFH in the control group increased by 243 µ m from 624 (±268) µ m at baseline to 867 (±303) µ m the next morning ( P < 0.01) but decreased in the posturing group by 150 µ m from 728 (±416) to 578 (±445) µ m ( P = 0.03). There was a significant association of the SFFH the next morning with posturing ( P < 0.01) and SFFH at baseline ( P < 0.01), but not with location of primary break ( P = 0.20). The change in SFFH from baseline to the next morning was significantly associated with posturing and primary break location ( P < 0.01), but not with SFFH at baseline ( P = 0.21).

CONCLUSION

Preoperative posturing is an effective measure to prevent progression of macular detachment in macula-off retinal detachment.

A presaccadic perceptual impairment at the postsaccadic location of the blindspot

Saccadic eye movements are preceded by profound changes in visual perception. These changes have been linked to the phenomenon of 'forward remapping', in which cells begin to respond to stimuli that appear in their post-saccadic receptive field before the eye has moved. Few studies have examined the perceptual consequences of remapping of areas of impaired sensory acuity, such as the blindspot. Understanding the perceptual consequences of remapping of scotomas may produce important insights into why some neurovisual deficits, such as hemianopia are so intractable for rehabilitation. The current study took advantage of a naturally occurring scotoma in healthy participants (the blindspot) to examine pre-saccadic perception at the upcoming location of the blindspot. Participants viewed stimuli monocularly and were required to make stimulus-driven vertical eye-movements. At a variable latency between the onset of saccade target (ST) and saccade execution a discrimination target (DT) was presented at one of 4 possible locations; within the blindspot, contralateral to the blindspot, in post-saccadic location of the blindspot and contralateral to the post-saccadic location of the blindspot. There was a significant perceptual impairment at the post-saccadic location of the blindspot relative to the contralateral post-saccadic location of the blindspot and the post-saccadic location of the blindspot in a no-saccade control condition. These data are consistent with the idea that the visual system includes a representation of the blindspot which is remapped prior to saccade onset.

Efficient versus inefficient visual search as training for saccadic re-referencing to an extrafoveal location

Central vision loss is one of the leading causes of visual impairment in the elderly and its frequency is increasing. Without formal training, patients adopt an unaffected region of the retina as a new fixation location, a preferred retinal locus (PRL). However, learning to use the PRL as a reference location for saccades, that is, saccadic re-referencing, is protracted and time-consuming. Recent studies showed that training with visual search tasks can expedite this process. However, visual search can be driven by salient external features - leading to efficient search, or by internal goals, usually leading to inefficient, attention-demanding search. We compared saccadic re-referencing training in the presence of a simulated central scotoma with either an efficient or an inefficient visual search task. Participants had to respond by fixating the target with an experimenter-defined retinal location in the lower visual field. We observed that comparable relative training gains were obtained in both tasks for a number of behavioral parameters, with higher training gains for the trained task, compared to the untrained task. The transfer to the untrained task was only observed for some parameters. Our findings thus confirm and extend previous research showing comparable efficiency for exogenously and endogenously driven visual search tasks for saccadic re-referencing training. Our results also show that transfer of training gains to related tasks may be limited and needs to be tested for saccadic re-referencing-training paradigms to assess its suitability as a training tool for patients.

Correlation between Central Visual Field Defects and Stereopsis in Patients with Early-to-Moderate Visual Field Loss

PURPOSE

To investigate the association between stereoacuity and the presence of central visual field defects (CVFDs) due to glaucoma.

DESIGN

A prospective, cross-sectional cohort study.

PARTICIPANTS

Participants with early-to-moderate glaucoma with a visual acuity better than 20/40, less than a 2-line difference in visual acuity between eyes, and 2 reliable Humphrey visual fields (VFs) (24-2 SITA standard) with mean deviation (MD) in the worse eye better than - 12 dB.

METHODS

Stereoacuity was measured using the Titmus stereo test. Participants with a significant field defect (P < 0.005) in any 1 of the central 4 points in the 24-2 SITA standard total deviation map in either eye were classified as having a CVFD. Vision-related quality of life (VR-QOL) was measured using 25-item National Eye Institute Visual Function Questionnaire scores. Logistic regression was used to determine the associations between the level of stereoacuity and age, sex, race, glaucoma type, presence of CVFDs, visual acuity, contrast sensitivity, and VF MD.

MAIN OUTCOME MEASURES

Stereoacuity in the CVFD and non-CVFD groups.

RESULTS

Sixty-five participants met the inclusion criteria. The mean age of the participants was 64.3 ± 8.0 years, and 64.6% were women. The median stereoacuity was 60 arc seconds (interquartile range [IQR], 40-120 arc seconds). Forty-two (65%) patients had CVFDs, and 23 (35%) patients did not. The median stereoacuity of the CVFD group was worse than that of the non-CVFD group (60 arc seconds [IQR, 50-140 arc seconds] vs. 40 arc seconds [IQR, 40-80 arc seconds], respectively; P = 0.001). The non-CVFD group had a higher percentage of participants with normal stereopsis than the non-CVFD group (61% vs. 21%, respectively; P = 0.001). A multivariable analysis found that the presence of CVFDs was associated with worse stereopsis levels (odds ratio, 4.49; P = 0.021). The CVFD group had a lower Visual Functioning Questionnaire-25 (VFQ-25) composite score (84.0 vs. 91.4; P = 0.004) and lower VFQ-25 subscale scores for general vision, near activities, and mental health (P < 0.05).

CONCLUSIONS

Central visual field defects were associated with increased odds of poor stereoacuity in patients with early-to-moderate glaucomatous VF loss. Specifically, patients without CVFDs are more likely to have normal stereopsis and higher VR-QOL than those with CVFDs. Patients with CVFDs should be counseled regarding how depth perception difficulties may affect daily living.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Visual Fields in Epidemic Retinitis

AIM

The aim of the study is to analyze visual fields defects (VFDs) in epidemic retinitis (ER).

METHODS

Patients with ER and Humphrey's visual field (HFA) 30-2 performed after resolution were studied. VFD severity grading was performed. Patients treated with oral doxycycline (Group-A) versus doxycycline-steroids (group-B) were compared.

RESULTS

Thirty-five eyes of 25 patients were studied. Nasal, inferior, temporal and central VFD were seen in 19 (54.2%), 13 (37.1%), 7 (20%) and 6 (17.1%) eyes, respectively. Grade 0, 1, 2 and 3 VFDs were seen in 4 (11.4%), 15 (42.8%), 12 (34.2%) and 4 (11.4%) eyes respectively. Seven eyes with ≥1 year of follow-up post-resolution also showed grade 0-3 scotomas. Mean severity of scotoma was grade 1.15 (Median: 1) and 1.42 (Median: 1.5) in groups A (n = 13) and B (n = 14), respectively (p = .637).

CONCLUSION

ER can cause VFD persisting long after resolution. Treatment with oral doxycycline without steroids was non-inferior to combined treatment with respect to VFD.

A CASE OF RAPIDLY PROGRESSIVE RETINOPATHY ASSOCIATED WITH PEMBROLIZUMAB IMMUNOTHERAPY FOR METASTATIC UROTHELIAL CARCINOMA

PURPOSE

To describe a novel case of bilateral rapidly progressive retinopathy after immunotherapy with pembrolizumab for metastatic urothelial carcinoma.

METHODS

Case report.

RESULTS

A 64-year-old man undergoing pembrolizumab immunotherapy was referred to our hospital because of bilateral acute vision loss. His best-corrected visual acuity was 20/30 in the right eye and 20/320 in the left eye, and a visual field test revealed central and paracentral scotomas in the right eye and central scotoma in the left eye. We suspected immune-related retinopathy based on the progressive photoreceptor damage with abnormal electroretinogram findings, absence of overt intraocular inflammation, and presence of malignancy. Cessation of pembrolizumab and steroid pulse therapy followed by decreasing oral prednisolone improved visual function and photoreceptor damage, although there was recurrence after pembrolizumab was restarted.

CONCLUSION

We reported a case of rapidly progressive retinopathy that may have been triggered by pembrolizumab immunotherapy for metastatic urothelial carcinoma. High-dose corticosteroid pulse therapy was effective in reversing photoreceptor damage.

Relationships of Macular Functional Impairment With Structural and Vascular Changes According to Glaucoma Severity

Purpose

To determine the pointwise relationships of central visual field (VF) defects with macular ganglion cell loss and macular vessel density (VD) loss during various stages of glaucoma.

Methods

Eyes with primary open-angle glaucoma (POAG) were subjected to optical coherence tomography (OCT) and OCT angiography (OCTA) to evaluate macular ganglion cell layer (GCL) thickness and macular VD in the superficial and deep vascular complexes (SVC and DVC). OCT, OCTA, and VF locations were matched after correcting for retinal ganglion cell (RGC) displacement. Pointwise correlations of GCL thickness and VDs of the SVC and DVC with central VF sensitivity (VFS) were evaluated by Pearson's correlation analysis and compared in eyes with early and advanced POAG by Meng's test.

Results

Of the 100 eyes, 52 and 48 were classified as early and advanced POAG. Macular VD showed overall better correlation with central VFS than GCL thickness in both the early and advanced groups. SVC density showed the strongest correlation with central VFS in all groups (R = 0.327 in early group, R = 0.325 in advanced group, all P < 0.001). Although DVC density showed better correlation with VFS (R = 0.311) than GCL thickness (R = 0.212) in the early group (P < 0.001), the correlation was comparable in the advanced group (R = 0.199 and 0.176, respectively, P = 0.254).

Conclusions

After adjustment for RGC displacement, macular SVC density was better correlated with central VFS than macular GCL thickness in both early and advanced POAG. Macular DVC density showed better correlation with VFS than GCL thickness in early but not in advanced POAG, indicating that DVC loss may be involved in early central VF loss.

Dual Sensory Impairment: Impact of Central Vision Loss and Hearing Loss on Visual and Auditory Localization

Purpose

In the United States, AMD is a leading cause of low vision that leads to central vision loss and has a high co-occurrence with hearing loss. The impact of central vision loss on the daily functioning of older individuals cannot be fully addressed without considering their hearing status. We investigated the impact of combined central vision loss and hearing loss on spatial localization, an ability critical for social interactions and navigation.

Methods

Sixteen older adults with central vision loss primarily due to AMD, with or without co-occurring hearing loss, completed a spatial perimetry task in which they verbally reported the directions of visual or auditory targets. Auditory testing was done with eyes open in a dimly lit room or with a blindfold. Twenty-three normally sighted, age-matched, and hearing-matched control subjects also completed the task.

Results

Subjects with central vision loss missed visual targets more often. They showed increased deviations in visual biases from control subjects as the scotoma size increased. However, these deficits did not generalize to sound localization. As hearing loss became more severe, the sound localization variability increased, and this relationship was not altered by coexisting central vision loss. For both control and central vision loss subjects, sound localization was less reliable when subjects wore blindfolds, possibly due to the absence of visual contextual cues.

Conclusions

Although central vision loss impairs visual localization, it does not impair sound localization and does not prevent vision from providing useful contextual cues for sound localization.

SPONTANEOUS CLOSURE AND RECURRENT OPENING TIMES TWO OF A MACULAR HOLE IN A SURGICALLY NAIVE EYE

PURPOSE

To report a case of an idiopathic macular hole with recurrent opening and spontaneous closure in a surgically naive eye.

METHODS

A retrospective review of medical records was performed in addition to a review of the current literature.

RESULTS

An 82-year-old man was referred for the management of a full-thickness macular hole in the right eye. Visual acuity was 20/60, and dilated fundus examination was notable for a posterior vitreous detachment, macular hole, and mild epiretinal membrane. Optical coherence tomography confirmed the presence of a full-thickness macular hole. The patient declined surgical intervention and elected to observe. Five weeks later, optical coherence tomography confirmed spontaneous closure. One year later, a recurrent partial thickness outer retinal hole was noted on dilated fundus examination and optical coherence tomography that subsequently spontaneously closed for the second time. The following year, the patient represented with a new scotoma and metamorphopsia and was found to have a full-thickness macular hole. This time the patient was elected for surgical intervention (25-gauge pars plana vitrectomy, epiretinal membrane peel, and 14% C3F8), resulting in closure of the macular hole and improvement in visual acuity to 20/25+1.

CONCLUSION

This case highlights a rare presentation of a see-saw pattern of opening and closing of a macular hole in a treatment-naive eye. The presence of a posterior vitreous detachment and epiretinal membrane suggests that other factors than anterior-posterior and tangential traction may be a contributing in the formation and closure of idiopathic macular holes.

Relationship Between Suppression Scotomas and Stereoacuity in Anisometropic Amblyopia With Successfully Treated Visual Acuity

Purpose

The purpose of this study was to investigate the relationship among suppression scotoma size, stereoacuity, and four-prism base-out test (4ΔBOT) results in anisometropic amblyopia with successfully treated visual acuity.

Methods

We included 103 cases of anisometropic amblyopia successfully treated for visual acuity without strabismus. Stereoacuity was measured using a Randot Stereotest. The size of the suppression scotomas was measured using a new device, the polarized four dot (P4D) test. This is a modification of the Worth 4 dot test (W4D) device. The patients were divided into three groups based on the 4ΔBOT results: normal (group A = 29 cases), subnormal (group B = 48 cases), and abnormal (group C = 26 cases) response groups. The horizontal diameter of the suppression scotomas and stereoacuity in logarithmic values with a base of 20 seconds of arc (″) were compared among the 3 groups.

Results

The mean age at P4D testing was 8.4 ± 2.1 years. The average horizontal diameters of the suppression scotomas were 0.35 ± 0.79Δ, 2.01 ± 0.82Δ, and 5.50 ± 2.72Δ in groups A, B, and C, respectively, showing significant differences (A versus B: P < 0.0001, A versus C: P < 0.0001, and B versus C: P < 0.0001; 1-way ANOVA). The average logarithmic stereoacuity were 1.07 (24.95″), 1.22 (38.84″), and 1.47 (82.79″) in groups A, B, and C, respectively, thereby showing significant differences between the groups (A versus B: P < 0.0001, A versus C: P < 0.0001, and B versus C: P < 0.0001; 1-way ANOVA). Stereoacuity and horizontal diameter of the suppression scotoma were strongly correlated (r = 0.732, P < 0.0001).

Conclusions

The suppression scotoma size measured using P4D correlated significantly with stereoacuity and the 4ΔBOT results.

Consistency of preferred retinal locus across tasks and participants trained with a simulated scotoma

After loss of central vision following retinal pathologies such as macular degeneration (MD), patients often adopt compensatory strategies including developing a "preferred retinal locus" (PRL) to replace the fovea in tasks involving fixation. A key question is whether patients develop multi-purpose PRLs or whether their oculomotor strategies adapt to the demands of the task. While most MD patients develop a PRL, clinical evidence suggests that patients may develop multiple PRLs and switch between them according to the task at hand. To understand this, we examined a model of central vision loss in normally seeing individuals and tested whether they used the same or different PRLs across tasks after training. Nineteen participants trained for 10 sessions on contrast detection while in conditions of gaze-contingent, simulated central vision loss. Before and after training, peripheral looking strategies were evaluated during tasks measuring visual acuity, reading abilities and visual search. To quantify strategies in these disparate, naturalistic tasks, we measured and compared the amount of task-relevant information at each of 8 equally spaced, peripheral locations, while participants performed the tasks. Results showed that some participants used consistent viewing strategies across tasks whereas other participants' strategies differed depending on task. This novel method allows quantification of peripheral vision use even in relatively ecological tasks. These results represent one of the first examinations of peripheral viewing strategies across tasks in simulated vision loss. Results suggest that individual differences in peripheral looking strategies following simulated central vision loss may model those developed in pathological vision loss.

Training With Simulated Scotoma Leads to Behavioral Improvements Through at Least Two Distinct Mechanisms

Purpose

Individuals with central vision loss due to macular degeneration (MD) often spontaneously develop a preferred retinal locus (PRL) outside the area of retinal damage, which they use instead of the fovea. Those who develop a stable PRL are more successful at coping with their vision loss. However, it is unclear whether improvements in visual performance at the PRL are specific to that retinal location or are also observed in other parts of the retina. Perceptual learning literature suggests that the retinal specificity of these effects provides insight about the mechanisms involved. Better understanding of these mechanisms is necessary for the next generation of interventions and improved patient outcomes.

Methods

To address this, we trained participants with healthy vision to develop a trained retinal locus (TRL), analogous to the PRL in patients. We trained 24 participants on a visual search task using a gaze-contingent display to simulate a central scotoma.

Results

Results showed retinotopically specific improvements in visual crowding only at the TRL; however, visual acuity improved in both the TRL and in an untrained retinal locus.

Conclusions

These results suggest that training with an artificial scotoma involves multiple mechanistic levels, some location-specific and some not, and that simulated scotoma training paradigms likely influence multiple mechanisms simultaneously. Eye movement analysis suggests that the non-retinotopic learning effects may be related to improvements in the capability to maintain a stable gaze during stimulus presentation. This work suggests that effective interventions promoting peripheral viewing may influence multiple mechanisms simultaneously.

Oculomotor changes following learned use of an eccentric retinal locus

People with bilateral central vision loss sometimes develop a new point of oculomotor reference called a preferred retinal locus (PRL) that is used for fixating and planning saccadic eye movements. How individuals develop and learn to effectively use a PRL is still debated; in particular, the time course of learning to plan saccades using a PRL and learning to stabilize peripheral fixation at the desired location. Here we address knowledge limitations through research describing how eye movements change as a person learns to adopt an eccentric retinal locus. Using a gaze-contingent, eye tracking-guided paradigm to simulate central vision loss, 40 participants developed a PRL by engaging in an oculomotor and visual recognition task. After 12 training sessions, significant improvements were observed in six eye movement metrics addressing different aspects involved in learning to use a PRL: first saccade landing dispersion, saccadic re-referencing, saccadic precision, saccadic latency, percentage of useful trials, and fixation stability. Importantly, our analyses allowed separate examination of the stability of target fixation separately from the dispersion and precision of the landing location of saccades. These measures explained 50% of the across-subject variance in accuracy. Fixation stability and saccadic precision showed a strong, positive correlation. Although there was no statistically significant difference in rate of learning, individuals did tend to learn saccadic precision faster than fixation stability. Saccadic precision was also more associated with accuracy than fixation stability for the behavioral task. This suggests effective intervention strategies in low vision should address both fixation stability and saccadic precision.

Saccades during visual search in macular degeneration

Macular degeneration (MD) compromises both high-acuity vision and eye movements when the foveal regions of both eyes are affected. Individuals with MD adapt to central field loss by adopting a preferred retinal locus (PRL) for fixation. Here, we investigate how individuals with bilateral MD use eye movements to search for targets in a visual scene under realistic binocular viewing conditions. Five individuals with binocular scotomata, 3 individuals with monocular scotomata and 6 age-matched controls participated in our study. We first extensively mapped the binocular scotoma with an eyetracker, while fixation was carefully monitored (Vullings & Verghese, 2020). Participants then completed a visual search task where 0, 1, or 2 Gaussian blobs were distributed randomly across a natural scene. Participants were given 10 s to actively search the display and report the number of blobs. An analysis of saccade characteristics showed that individuals with binocular scotomata made more saccades in the direction of their scotoma than controls for the same directions. Saccades in the direction of the scotoma were typically of small amplitude, and did not fully uncover the region previously hidden by the scotoma. Rather than make more saccades to explore this hidden region, participants frequently made saccades back toward newly uncovered regions. Backward saccades likely serve a similar purpose to regressive saccades exhibited during reading in MD, by inspecting previously covered regions near the direction of gaze. Our analysis suggests that the higher prevalence of backward saccades in individuals with binocular scotomata might be related to the PRL being adjacent to the scotoma.

Multi-res: An interface for improving reading without central vision

Loss of sharp foveal vision, as is inherent to Macular Degeneration (MD), severely impacts reading. One strategy for preserving patients' reading ability involves a one-by-one serial visual presentation (SVP) of words, whereby words are viewed extrafoveally. However, the method is limited as patients often retain the natural tendency to foveate words, thus bringing those words in the scotomal region. Additionally, SVP offers no compensation for the fact that orthographic input is degraded outside the fovea. Addressing these issues, here we tested a novel interface wherein texts are presented word-by-word, but with multiple repetitions (Multi-Res) of each word being displayed simultaneously around the fovea. We hypothesized that the Multi-Res setup would lead readers to make fewer detrimental eye movements, and to recognize words faster as a consequence of multiplied orthographic input. We used eye-tracking to simulate a gaze-contingent foveal scotoma in normally-sighted participants, who read words either in classic SVP or in Multi-Res mode. In line with our hypotheses, reading was drastically better in the Multi-Res condition, with faster recognition, fewer saccades and increased oculomotor stability. We surmise that the Multi-Res method has good potential for improving reading in central vision loss, over and above classic SVP techniques.

Application of Spatial Cues and Optical Distortions as Augmentations during Virtual Reality (VR) Gaming: The Multifaceted Effects of Assistance for Eccentric Viewing Training

The present study investigates the effects of peripheral spatial cues and optically distorting augmentations over eccentric vision mechanisms in normally sighted participants with simulated scotoma. Five different augmentations were tested inside a virtual reality (VR)-gaming environment. Three were monocular spatial cues, and two were binocular optical distortions. Each was divided into three conditions: baseline with normal viewing, augmentation with one of the assistance methods positioned around the scotoma, and one with only the simulated central scotoma. The study found that the gaming scenario induced eccentric viewing for the cued augmentation groups, even when the peripheral assistance was removed, while for the optical distortions group, the eccentric behavior disappeared after the augmentation removal. Additionally, an upwards directionality of gaze relative to target during regular gaming was found. The bias was maintained and implemented during and after the cued augmentations but not after the distorted ones. The results suggest that monocular peripheral cues could be better candidates for implementing eccentric viewing training in patients. At the same time, it showed that optical distortions might disrupt such behavior. Such results are noteworthy since distortions such as zoom are known to help patients with macular degeneration see targets of interest.

Combined central retinal vein and cilioretinal artery occlusion in a 25-year-old woman

We report a case of a 25-year-old woman with sudden and painless diminution in vision and central scotoma in her left eye (LE). She was a smoker and had been taking combined oral contraceptive (COC) pills for 1 year. On admission, the best-corrected visual acuity (BCVA) was 1,5/50 in the LE.

Posterior segment examination revealed optic disc edema with flame-shaped retinal hemorrhages, mildly tortuous and dilated retinal veins. Moreover, retinal edema in the peripapillary and perimacular region, foci of hemorrhages and Roth’s spots in the posterior pole, as well as pale superior papillomacular bundle were observed.

Fundus fluorescein angiography (FFA) confirmed the delayed flow of contrast through the cilioretinal artery in the LE. The clinical picture suggested left central retinal vein (CRVO) with cilioretinal artery occlusion (CLRAO). All laboratory and imaging tests were normal except for homozygous methylenetetrahydrofolate reductase (MTHFR) gene mutation (A1298C genotypes). However, serum homocysteine (Hcy) level was normal. Low molecular weight heparin (LMWH) treatment was administered. Retinal lesions, as well as BCVA improved, but central scotoma remained.

Abbreviations: aPTT = activated partial thromboplastin time, BCVA = best-corrected visual acuity, CBC = complete blood count, CLRAO = cilioretinal artery occlusion, COC = combined oral contraceptive, CRA = central retinal artery, CRP = serum C-reactive protein, CRVO = central retinal vein occlusion, CT = computed tomography, CTA = computed tomography angiography, ECG = electrocardiography, ESR = erythrocyte sedimentation rate, FERG = flash electroretinogram, FFA = fundus fluorescein angiography, GCA = ganglion cell analysis, GCL = ganglion cell layer, Hcy = homocysteine, ICGA = indocyanine green angiography, INR = international normalized ratio, IOP = intraocular pressure, IPL = inner plexiform layer, LE = left eye, LMWH = low molecular weight heparin, mfERG = multifocal electroretinogram, MTHFR = methylenetetrahydrofolate reductase, OCT = optical coherence tomography, RE = right eye, VF = visual field

Ocular and Hemodynamic Factors Contributing to the Central Visual Function in Glaucoma Patients With Myopia

Purpose

The purpose of this study was to investigate the ocular and hemodynamic factors contributing to the central visual function in glaucoma patients with myopia.

Methods

This study was a prospective observational study, which included 236 eyes of 140 patients with normal-tension glaucoma (NTG), which includes 114 eyes with mild myopia (axial length ≥24 and <26 mm) and 122 eyes with moderate-to-severe myopia (axial length ≥26 mm). Ocular characteristics were axial length and posterior pole profiles, including peripapillary atrophy (PPA) to disc area ratio, disc tilt ratio, disc torsion, and disc-foveal angle. Hemodynamic factors included standard deviation of the mean of qualified normal-to-normal intervals (SDNN) of a heart rate variability (HRV) test and vessel density (VD) parameters from optical coherence tomography angiography (OCTA). The root mean square error was estimated as a measure of the VD fluctuation. Association between ocular characteristics and VD parameters of the OCTA with the central sensitivity of the 10-degree visual field or the presence of central scotoma were analyzed.

Results

Deep layer VD of the peripapillary and macular areas showed significant differences between mild and moderate-to-severe myopia (P = 0.034 and P = 0.045, respectively). Structural parameters, especially PPA to disc area ratio, had significant correlation with peripapillary VD parameters in myopic eyes. Lower SDNN value (ß = 0.924, P = 0.011), lower deep VD of the macular area (ß = 0.845, P = 0.001), and greater fluctuation of deep VD in the peripapillary area (ß = 1.517, P = 0.005) were associated with the presence of central scotoma in patients with glaucoma with myopia in multivariate logistic regression analysis.

Conclusions

The structural changes by myopia, especially in the peripapillary region, affected VD parameters in myopic eyes. Lower deep VD and greater VD fluctuation in the peripapillary region showed association with central scotoma in patients with glaucoma with myopia, suggesting both structural and vascular changes by myopia may be related to central visual function in glaucoma patients with myopia.

Structure-function analysis of MP3 microperimetry versus Octopus perimetry in central glaucomatous visual field defects

INTRODUCTION

To compare the structure-function relationship with microperimetry and Octopus perimetry in primary open angle glaucoma (POAG) patients with central visual field (VF) defects.

METHODS

40 eyes of 24 patients with POAG were enrolled. Circumpapillary retinal nerve fiber layer (cpRNFL) analysis measured by spectral-domain optical coherence tomography (SD-OCT) of the superotemporal, temporal, and inferotemporal optic nerve head (ONH) sectors were related to corresponding microperimetric and Octopus VF clusters using the G2 grid-pattern with dynamic strategy, respectively. The structure-function relationships of both devices were assessed via a segmented regression, as well as linear regression across overall SD-OCT cpRNFL values and outside normative (<1%) SD-OCT cpRNFL values.

RESULTS

Linear and segmented regression fits were similar with both devices. Across overall cpRNFL sectorial values, structure-function relations for the superotemporal, temporal and inferotemporal sectors were R2=0.176 (p=<0.001), R2=0.008 (p=0.069), and R2=0.294 (p=<0.001) for microperimetry, and R2= 0.189 (p=<0.001), R2= 0.020 (p=0.002), and R2= 0.326 (p=<0.001) for Octopus perimetry. For corresponding values outside normative limits (<1%), the relationships were R2=0.113 (p=<0.001), R2=0.001 (p=0.836), and R2=0.420 (p=<0.001) for microperimetry, and R2= 0.192 (p=<0.001), R2= 0.002, (p=0.336), and R2= 0.366 (p=<0.001) for Octopus perimetry.

DISCUSSION/CONCLUSION

Structure-function analysis was similar for both devices. Fundus-tracking should be further evaluated in a longitudinal setting in patients affected by glaucoma.

Case Report: Bilateral Cecocentral Visual Field Defect Secondary to Congenital Optic Disc Pit

SIGNIFICANCE

Congenital optic disc pits are known to cause complications, commonly maculopathy due to retinoschisis and/or neurosensory retinal detachment. Retinal nerve fiber layer defects with associated visual field defects without maculopathy are another complication and can result in decreased visual function but have rarely been reported in the literature, especially bilaterally.

PURPOSE

This case report describes a patient with bilateral cecocentral visual field defects due to congenital optic nerve pits without associated maculopathy.

CASE REPORT

A 42-year-old Black man presented with blur symptoms at near uncorrected. Of note, there was no history of substance abuse or nutritional deficiencies. Best-corrected acuities were 20/20 in the right eye and 20/30 in the left eye. Clinical examination revealed bilateral focal grayish depression of the temporal optic nerve cup with associated papillomacular retinal nerve fiber layer defects. Optical coherence tomography (OCT) imaging revealed bilateral focal excavation of the temporal cup, temporal thinning of the retinal nerve fiber layer, and correlated binasal thinning of the ganglion cell complex, in the absence of retinoschisis or neurosensory detachment. Threshold visual field testing revealed stable bilateral cecocentral visual field defects. A diagnosis of bilateral cecocentral visual field defect secondary to congenital optic disc pits was made based on the patient's history and clinical examination.

CONCLUSIONS

A cecocentral visual field defect, unrelated to maculopathy, is a less common complication of congential optic disc pits that can cause decreased visual function. This case report provides evidence of this bilateral ocular condition and reviews the reported clinical, OCT, and threshold visual field manifestations of the disease. Specifically, spectral-domain OCT ganglion cell analysis seems useful in localizing the visual field defect.

Introducing the 24-2C Visual Field Test in Neuro-Ophthalmology

PURPOSE

The Humphrey 24-2C visual field test is a modified 24-2 visual field test that incorporates 10 additional test points in the central 10° of vision. This study compares the new 24-2C test to the standard Humphrey 10-2 visual field test in patients presenting for neuro-ophthalmology evaluation to evaluate its ability to detect central visual field defects.

METHODS

Twenty-five neuro-ophthalmology patients (42 eyes) underwent both 24-2C and 10-2 visual field testing using the Humphrey perimeter. The number of flagged total deviation (TD) and pattern deviation (PD) points of the 10 added test points of the 24-2C were compared with the corresponding 10-2 fields at the P < 5%, P < 2%, and P < 1% significance levels. The total number of flagged TD points were further analyzed by diagnosis. An experienced neuro-ophthalmologist evaluated all visual fields, commenting on the added value for clinical practice.

RESULTS

There was no significant difference between the number of flagged TD and PD points of the 10 extra 24-2C points and corresponding 10-2 points at all significance levels. When analyzed by diagnosis, there was no significant difference in the number of flagged TD points in patients with optic neuritis, ischemic optic neuropathy, optic atrophy, and no neuro-ophthalmic disease. The added 24-2C points aided in identifying visual field defects and areas of spared central vision and had similar diagnostic value as the 10-2.

CONCLUSIONS

The 24-2C is able to detect visual field loss in the central 10° that corroborates with loss detected in the 10-2 pattern. The 24-2C exhibits potential to be used as a hybrid between the 24-2 and 10-2 to better evaluate visual field defects.

The retinal and perceived locus of fixation in the human visual system

Due to the dramatic difference in spatial resolution between the central fovea and the surrounding retinal regions, accurate fixation on important objects is critical for humans. It is known that the preferred retinal location (PRL) for fixation of healthy human observers rarely coincides with the retinal location with the highest cone density. It is not currently known, however, whether the PRL is consistent within an observer or is subject to fluctuations and, moreover, whether observers' subjective fixation location coincides with the PRL. We studied whether the PRL changes between days. We used an adaptive optics scanning laser ophthalmoscope to project a Maltese cross fixation target on an observer's retina and continuously imaged the exact retinal location of the target. We found that observers consistently use the same PRL across days, regardless of how much the PRL is displaced from the cone density peak location. We then showed observers small stimuli near the visual field location on which they fixated, and the observers judged whether or not the stimuli appeared in fixation. Observers' precision in this task approached that of fixation itself. Observers based their judgment on both the visual scene coordinates and the retinal location of the stimuli. We conclude that the PRL in a normally functioning visual system is fixed, and observers use it as a reference point in judging stimulus locations.

An audio-visual motor training improves audio spatial localization skills in individuals with scotomas due to retinal degenerative diseases

Several studies have shown that impairments in a sensory modality can induce perceptual deficits in tasks involving the remaining senses. For example, people with retinal degenerative diseases like Macular Degeneration (MD) and with central scotoma show biased auditory localization abilities towards the visual field's scotoma area. This result indicates an auditory spatial reorganization of cross-modal processing in people with scotoma when the visual information is impaired. Recent works showed that multisensory training could be beneficial to improve spatial perception. In line with this idea, here we hypothesize that audio-visual and motor training could improve people's spatial skills with retinal degenerative diseases. In the present study, we tested this hypothesis by testing two groups of scotoma patients in an auditory and visual localization task before and after a training or rest performance. The training group was tested before and after multisensory training, while the control group performed the two tasks twice after 10 min of break. The training was done with a portable device positioned on the finger, providing spatially and temporally congruent audio and visual feedback during arm movement. Our findings show improved audio and visual localization for the training group and not for the control group. These results suggest that integrating multiple spatial sensory cues can improve the spatial perception of scotoma patients. This finding ignites further research and applications for people with central scotoma for whom rehabilitation is classically focused on training visual modality only.

Impact of living with a bilateral central vision loss due to geographic atrophy-qualitative study

OBJECTIVE

Geographic atrophy (GA), a type of dry age-related macular degeneration, affects vision as central vision loss (CVL). The challenges faced due to bilateral CVL in activities of daily living and strategies taken to overcome those challenges are not very well understood in the Indian population. This qualitative study aims to understand the impact on everyday life activities and related adaptive and coping strategies in people with long-standing bilateral CVL due to GA in India.

DESIGN, PARTICIPANTS, SETTING AND METHODS

A qualitative study using a semistructured face-to-face interview was conducted on 10 people with bilateral CVL after obtaining written informed consent. The interviews were audio-recorded, and were transcribed verbatim. Thematic analysis was carried out to understand the challenges faced and adaptive methods due to the impact of CVL.

RESULTS

Ten participants (50% male) with a median age (IQR) of 72 (70, 74) years were interviewed. All the participants had best-corrected visual acuity of ≤6/60 in the better eye and reported an absolute central scotoma with the home Amsler chart. Qualitative thematic analysis identified four main themes: challenges in everyday living (difficulty in face identification, reading), challenges with lifestyle and socialisation (driving, cooking, reading for a longer duration, watching TV, socially inactive), psychological implications (depression, poor self-esteem, fear due to poor vision) and strategies to overcome the challenges (voice identification, technology support).

CONCLUSION

GA has a severe negative impact on the quality of life in people with CVL. Inability to recognise faces was the main reason for dependency on others and being socially disconnected. The findings will help clinicians in providing improved rehabilitative care.

An implementation of Bubble Magnification did not improve the video comprehension of individuals with central vision loss

PURPOSE

People with central vision loss (CVL) watch television, videos and movies, but often report difficulty and have reduced video comprehension. An approach to assist viewing videos is electronic magnification of the video itself, such as Bubble Magnification.

METHODS

We created a Bubble Magnification technique that displayed a magnified segment around the centre of interest (COI) as determined by the gaze of participants with normal vision. The 15 participants with CVL viewed video clips shown with 2× and 3× Bubble Magnification, and unedited. We measured video comprehension and gaze coherence.

RESULTS

Video comprehension was significantly worse with both 2× (p = 0.01) and 3× Bubble Magnification (p < 0.001) than the unedited video. There was no difference in gaze coherence across conditions (p ≥ 0.58). This was unexpected because we expected a benefit in both video comprehension and gaze coherence. This initial attempt to implement the Bubble Magnification method had flaws that probably reduced its effectiveness.

CONCLUSIONS

In the future, we propose alternative implementations of Bubble Magnification, such as variable magnification and bubble size. This study is a first step in the development of an intelligent-magnification approach to providing a vision rehabilitation aid to assist people with CVL.

CASE REPORT

The most common cause of visual field loss in ophthalmology is glaucoma. Other causes of visual field damage include local damage to the eye itself in intrabulbar or retrobulbar neuritis or injuries. However, they can also be caused by general diseases, e.g. in endocrine orbitopathy, toxic and nutritional neuropathy, or in diseases that are localized intracranially. Each of these findings in itself suggests the nature of the lesion, its intracranial location, lateral occurrence, as well as in which part of the visual pathway the lesion is located. The use of perimeter has therefore become the primary examination method, which is available, is not demanding and will quickly allow a diagnosis to be made. When found on a perimetric examination, it is necessary to indicate targeted imaging examinations, such as computed tomography or magnetic resonance imaging. The article describes a patient who was primarily examined at the Department of Ophthalmology, Faculty of Medicine, Comenius University and the University hospital of Bratislava. The patient reported visual field outages, and after subsequent computed tomography, she was interdisciplinary managed and surgery was done on at the Neurosurgical Department. After the operation, there was a significant improvement without a pathological finding on the perimeter.

Audio-Visual Thumble (AVT): A low-vision rehabilitation device using multisensory feedbacks

Since the 70s sensory substitution devices have been used for blind individuals to compensate for the lack of vision and enable them to perceive environment through intact sensory modalities. In this study, we present a rehabilitation device called Audio Visual Thumble (AVT), which is a small ring-like device with LED and buzzer, that can be worn on pharynx. We focus on a unique group of low-vision individuals with a black spot or scotoma in their visual field due to a disease called Macular Degeneration. The visual localization abilities of these individuals are highly impaired due to developing scotoma. We recently showed that also their audio localization skills are impaired [9]. Rehabilitation techniques developed so far for Macular Degeneration focus on visual modality only. Since audition can also be used to improve their spatial skills, we developed the AVT device. It permits to associate the multisensory information (audio and visual feedbacks) coming from the device with the own movement (proprioceptive feedback). We propose that the AVT has the potential to help people with visual dysfunctions to improve in the identification of audio and visual targets outside or at the edge of the residual visual field. AVT could be used for a wide range of applications combined with classical rehabilitation techniques in Macular Degeneration patients.Clinical relevance- This device can be an effective addition for low-vision rehabilitation experts and can be used combined with classical rehabilitation methods.

Using eye movements to detect visual field loss: a pragmatic assessment using simulated scotoma

Glaucoma is a leading cause of irreversible sight-loss and has been shown to affect natural eye-movements. These changes may provide a cheap and easy-to-obtain biomarker for improving disease detection. Here, we investigated whether these changes are large enough to be clinically useful. We used a gaze-contingent simulated visual field (VF) loss paradigm, in which participants experienced a variable magnitude of simulated VF loss based on longitudinal data from a real glaucoma patient (thereby controlling for other variables, such as age and general health). Fifty-five young participants with healthy vision were asked to view two short videos and three pictures, either with: (1) no VF loss, (2) moderate VF loss, or (3) advanced VF loss. Eye-movements were recorded using a remote eye tracker. Key eye-movement parameters were computed, including saccade amplitude, the spread of saccade endpoints (bivariate contour ellipse area), location of saccade landing positions, and similarity of fixations locations among participants (quantified using kernel density estimation). The simulated VF loss caused some statistically significant effects in the eye movement parameters. Yet, these effects were not capable of consistently identifying simulated VF loss, despite it being of a magnitude likely easily detectable by standard automated perimetry.

Hazard Detection With Monocular Bioptic Telescopes in a Driving Simulator

Purpose

In most states, people with reduced visual acuity may legally drive with the aid of a bioptic telescope. However, concerns have been raised that the ring scotoma may impair detection of peripheral hazards. Using a driving simulator, we tested the hypothesis that the fellow eye would be able to compensate for the ring scotoma when using a monocular telescope.

Methods

Sixteen bioptic users completed three drives with binocular viewing interleaved between three drives with monocular viewing. Forty pedestrians appeared and ran on the road for 1 second, including 26 within the ring scotoma, while participants were reading road signs through their own monocular telescopes. Head movements were analyzed to determine whether the pedestrian appeared before or only while using the telescope.

Results

For pedestrians that appeared only during bioptic use and were likely in the area of the ring scotoma, detection rates were significantly higher in binocular (fellow eye can compensate) than monocular (fellow eye patched) viewing (69% vs. 32%; P < 0.001); this was true for both current and noncurrent drivers. For pedestrians appearing before or after bioptic use, detection rates did not differ in binocular and monocular viewing. However, detection rates were even higher and reaction times shorter when the telescope was not being used.

Conclusions

Both current and noncurrent drivers'  fellow eyes were able to compensate, at least in part, for the ring scotoma.

Translational Relevance

When using monocular telescopes, the fellow eye reduces the impact of the ring scotoma on hazard detection in binocular viewing.