Assessment Of Visual Field Defects Research Articles

Objective Assessment of Visual Field Defects Caused by Optic Chiasm and Its Posterior Visual Pathway Injury.

To investigate the characteristics and objective assessment method of visual field defects caused by optic chiasm and its posterior visual pathway injury. Typical cases of visual field defects caused by injuries to the optic chiasm, optic tracts, optic radiations, and visual cortex were selected. Visual field examinations, visual evoked potential (VEP) and multifocal visual evolved potential (mfVEP) measurements, craniocerebral CT/MRI, and retinal optical coherence tomography (OCT) were performed, respectively, and the aforementioned visual electrophysiological and neuroimaging indicators were analyzed comprehensively. The electrophysiological manifestations of visual field defects caused by optic chiasm injuries were bitemporal hemianopsia mfVEP abnormalities. The visual field defects caused by optic tract, optic radiation, and visual cortex injuries were all manifested homonymous hemianopsia mfVEP abnormalities contralateral to the lesion. Mild relative afferent pupil disorder (RAPD) and characteristic optic nerve atrophy were observed in hemianopsia patients with optic tract injuries, but not in patients with optic radiation or visual cortex injuries. Neuroimaging could provide morphological evidence of damages to the optic chiasm and its posterior visual pathway. Visual field defects caused by optic chiasm, optic tract, optic radiation, and visual cortex injuries have their respective characteristics. The combined application of mfVEP and static visual field measurements, in combination with neuroimaging, can maximize the assessment of the location and degree of visual pathway damage, providing an effective scheme for the identification of such injuries.

Assessment of visual field defects and optic disc changes in patients with high myopia

Glaucoma is a leading cause of global irreversible blindness. Primary open angle glaucoma (POAG) is the most common form of glaucoma and affects 44.1 million individuals worldwide. Furthermore, there is a disproportionate burden of POAG in Asia, with Asians accounting for 53% (23.5 million) of POAG cases worldwide. While early detection of POAG is important in delaying or halting the progression of the disease, a better understanding of the interplay between major risk factors for POAG is crucial. aim of this study is to assess the effects of myopia on POAG in the patient attending MYH Indore OPD (central India). It is a hospital based, prospective, non-randomised case study. 60 eyes of high myopic patients and 60 eyes of general Ophthal OPD patients were evaluated. The statistical software namely SPSS 19.0, were used for the analysis of the data and Microsoft word and Excel have been used to generate graphs, tables etc. In our study, we found that, in high myopic patient, there were increase in chances of glaucomatous optic disc changes, and these changes were influenced by age and not influenced with gender, degree of myopia.

Eye-tracking-based visual field analysis (EFA): a reliable and precise perimetric methodology for the assessment of visual field defects

ObjectiveSeveral studies report evidence for training-related neuroplasticity in the visual cortex, while other studies suggest that improvements simply reflect inadequate eye fixation control during perimetric prediagnostics and postdiagnostics.Methods and analysisTo...

Assessment of visual field defects in cerebrovascular disease (CVD)

To expedite the rehabilitation process of CVD patients, it becomes imperative to identify and assess the extent of the Visual Field defect and the type of CVD. Through this study we aim to assess the visual field loss in patients following Cerebrovascular disease (CVD) and correlate the site and vessel involved with the Visual Field Loss. The study is a cross sectional study carried out over 3 months. All patients with anterior or posterior circulation stroke irrespective of the cause at 2 weeks following the episode of stroke formed a part of this study. They underwent a thorough ophthalmological assessment and Visual Field Assessment. Also, the corresponding radiological data was analysed for the site and the vessels involved in the CVD and correlated with the visual field defect obtained. A total of 25 patients were assessed with 88% being male and 12% female. Common co-morbidities were ischemic heart disease (IHD), diabetes mellitus (DM) and hypertension (HTN). Here, 100% of the patients with IHD had visual field loss as a symptom (P=0.032). All the patients who had gait abnormalities and giddiness as complaints were found to present primarily with visual field defect (P=0.032). When the Posterior Cerebral Artery (PCA) was involved visual field defect was seen in 100% of the patients (Left PCA, P=0.032) and in 60% of patients with Right PCA involvement (P=0.133). Hundred percent of patients with Right occipital lobe involvement had a visual field defect (P=0.032). PCA involvement with the Left Lower temporal field loss and also MCA involvement with Right nasal fields were found to correlate significantly (P= 0.015, 0.022, 0.023 respectively). Hence, incorporating Ophthalmological assessment in all patients of stroke helps in rehabilitation of the patients better and at the earliest. Keywords: Cerebrovascular disease, Nasal, Rehabilitation, Site of lesion, Temporal, Vascular territory, Visual field defect.

Chromatic Pupilloperimetry Measures Correlate With Visual Acuity and Visual Field Defects in Retinitis Pigmentosa Patients

PurposeTo evaluate the ability of chromatic pupilloperimetry to identify visual field (VF) defects in patients with retinitis pigmentosa (RP) and to test the correlation between pupilloperimetry impairment and retinal structural and functional measures.MethodsThe pupil responses of 10 patients with RP (mean age, 41.3 ± 16.2 years) and 32 healthy age-similar controls (mean age, 50.7 ± 15.5 years) for 54 focal blue and red stimuli presented in a 24-2 VF were recorded. The pupilloperimetry measures were correlated with Humphrey VF mean deviation, best-corrected visual acuity, and ellipsoid zone area.ResultsSubstantially lower percentage of pupil contraction and maximal pupil contraction velocity (MCV) were recorded in patients with RP throughout the VF in response to blue and red stimuli. The mean absolute deviation (MADEV) in the latency of MCV (LMCV) was significantly larger in patients compared with controls for blue and red stimuli (P = 1.0 × 10−7 and P = 1.0 × 10−6, respectively). The LMCV MADEV differentiated between patients and controls with high specificity and sensitivity (area under the receiver operating characteristic curve, 0.987 and 0.973 for blue and red, respectively). The MADEV of LMCV for blue stimuli correlated with best-corrected visual acuity (ρ = 0.938, P = 5.9 × 10−5) and ellipsoid zone area (ρ = −0.857; P = 0.002). The MADEV of LMCV for red stimuli correlated with Humphrey VF mean deviation (ρ = −0.709; P = 0.022). Minimizing the test to 15 targets maintained a diagnosis of retinal damage in patients with RP with high sensitivity and specificity (area under the receiver operating characteristic curve, 0.927).ConclusionsThe chromatic pupilloperimetry measures significantly correlated with retinal function and structure in patients with RP at various disease stages.Translational RelevanceChromatic pupilloperimetry may enable objective assessment of visual field defects and visual acuity in RP.

The Brentano Illusion Test (BRIT): An implicit task of perceptual processing for the assessment of visual field defects in neglect patients

ABSTRACT In brain damaged patients with unilateral spatial neglect (USN), the differential diagnosis between the presence and absence of a unilateral visual half-field deficit (VHFD) is hampered by the similarity of their phenomenology. The absence of stimuli detection in the contralateral visual field, indeed, can be due to the co-occurrence of USN and VHFD or the sole presence of the USN. The disentangling of the two conditions is required to devise more specific rehabilitation programmes. Daini et al. [2002. Exploring the syndrome of spatial unilateral neglect through an illusion of length. Experimental Brain Research, 144(2), 224–237.] reported a difference in performance for the two conditions when the tasks required the bisection of Brentano illusory stimuli. Only when USN and VHFD co-occurred, the leftward illusory effect was disrupted. Based on previous findings, in this cross-sectional study, we developed the Brentano Illusion Test (BRIT), a clinical tool that helps the identification of VHFD in USN patients. The BRIT is a simple behavioural test of line bisection aimed at verifying the presence or absence of implicit processing in USN and thus helping the diagnosis of VHFD in USN patients; it also provides normative data for the line bisection task and the length effect.

Chromatic Multifocal Pupillometer for Objective Perimetry and Diagnosis of Patients with Retinitis Pigmentosa

To assess visual field (VF) defects and retinal function objectively in healthy participants and patients with retinitis pigmentosa (RP) using a chromatic multifocal pupillometer. Cross-sectional study. The right eyes of 16 healthy participants and 13 RP patients. Pupil responses to red and blue light (peak, 485 and 625 nm, respectively) presented by 76 light-emitting diodes, 1.8-mm spot size at different locations of a 16.2° VF were recorded. Subjective VFs of RP patients were determined using chromatic dark-adapted Goldmann VFs (CDA-GVFs). Six healthy participants underwent 2 pupillometer examinations to determine test-retest reliability. Three parameters of pupil contraction were determined automatically: percentage of change of pupil size (PPC), maximum contraction velocity (MCV; in pixels per second), and latency of MCV (LMCV; in seconds). The fraction of functional VF was determined by CDA-GVF. In healthy participants, higher PPC and MCV were measured in response to blue compared with red light. The LMCV in response to blue light was relatively constant throughout the VF. Healthy participants demonstrated higher PPC and MCV and shorter LMCV in central compared with peripheral test points in response to red light. Test-retest correlation coefficients were 0.7 for PPC and 0.5 for MCV. In RP patients, test point in which the PPC and MCV were lower than 4 standard errors from the mean of healthy participants correlated with areas that were indicated as nonseeing by CDA-GVF. The mean absolute deviation in LMCV parameter in response to the red light between different test point was significantly higher in RP patients (range, 0.16-0.47) than in healthy participants (range, 0.02-0.16; P < 0.0001) and indicated its usefulness as a diagnostic tool with high sensitivity and specificity (area under the receiver operating characteristic curve (AUC), 0.97, Mann-Whitney-Wilcoxon analysis). Randomly reducing the number of test points to a total of 15 points did not significantly reduce the AUC in RP diagnosis based on this parameter. This study demonstrates the feasibility of using a chromatic multifocal pupillometer for objective diagnosis of RP and assessment of VF defects.

Study of visual field in healthy chronic smokers

Background: Visual disturbances caused by smoking have been studied extensively though the pathogenesis is poorly understood. The significance to diagnose visual field disturbances because of smoking is that prognosis for return of vision is always good if the consumption of tobacco is restrained timely. Aims & Objective: To study visual field in healthy smokers. Materials and Methods: In this study, subjects from the outpatient clinic were selected randomly: 30 healthy smokers and 30 nonsmokers. These subjects were divided into two groups: test (smokers) and control (nonsmokers). Ocular examination of all the subjects was done including intraocular pressure measurement and fundus examination. Further, visual field analysis was carried out using an automated perimeter (M700; Medmont International). Then, interpretation of visual field was done along with assessment of visual field defects. Values obtained were analyzed using Z-test and unpaired Student’s t-test. p-Value less than 0.05 was considered to be statistically significant. Results: Average deviation (AD) and patterned deviation (PD) were found to be significantly high in smokers as compared to nonsmokers (p < 0.001). It was also observed that AD and PD were significantly high if the smoking load (average number of cigarettes multiplied by average duration of smoking) is more than 50,000 (p < 0.005 and p < 0.02, respectively). In smokers, retinal sensitivity was found to decrease and the presence of localized scotomas was observed, but the central vision was found to be preserved. Conclusion: This study is important in diagnosing visual field defects in tobacco amblyopia to stop nicotine toxicity in time with early intervention, thereby preventing further damage to the optic nerve.

Customized, automated stimulus location choice for assessment of visual field defects.

To introduce a perimetric algorithm (gradient-oriented automated natural neighbor approach [GOANNA]) that automatically chooses spatial test locations to improve characterization of visual field (VF) loss without increasing test times. Computer simulations were undertaken to assess the performance of GOANNA. GOANNA was run on a 3° grid of 150 locations, and was compared with a zippy estimation by sequential testing (ZEST) thresholding strategy for locations in the 24-2 test pattern, with the remaining 98 locations being interpolated. Simulations were seeded using empirical data from 23 eyes with glaucoma that were measured at all 150 locations. The performance of the procedures was assessed by comparing the output thresholds to the input thresholds (accuracy and precision) and by evaluating the number of presentations required for the procedure to terminate (efficiency). When collated across whole-fields, there was no significant difference in accuracy, precision, or efficiency between GOANNA and ZEST. However, GOANNA targeted presentations on scotoma borders; hence it was more precise and accurate at locations where the sensitivity gradient within the VF was high. Compared with ZEST, GOANNA was marginally less precise in areas of the VF that had spatially uniform sensitivity, but improved accuracy and precision in regions surrounding scotoma edges. GOANNA provides a principled framework for automatic placement of additional test locations to provide spatially denser testing around the borders of VF loss.

Assessment of functional and morphometric endpoints in patients with non-arteritic anterior ischemic optic neuropathy (NAION)

The primary objective of this bi-center explorative pilot study was the quantitative assessment of visual field defects and retinal nerve fiber layer thickness (RNFT) over 6months in patients with acute non-arteritic anterior ischemic optic neuropathy (NAION), in order to elucidate the natural course of NAION and provide a reference dataset for future treatment studies. 16 patients (age 41-80years, nine males, seven females) suffering from acute NAION and presenting within 7days after onset of symptoms were included in this study. The following examinations were carried out at the initial visit (month 0) and at months 2, 4 and 6: entire (90°) visual field examination with automated static white-on-white perimetry, quantified by mean defect (MD); peripapillary retinal nerve fiber layer thickness (RNFT) measurement with spectral domain optical coherence tomography (SD-OCT); assessment of distant best correct visual acuity (D-BCVA) and a quantification of the relative afferent pupillary defect (RAPD) using the swinging flashlight test with neutral density filters. Perimetric Mean Defect (MD) and RNFT values were each compared between the consecutive visits using the non-parametric Friedman test. The initial MD was 6.2dB (IQR 5.0-7.4) without significant changes further on. RNFT was 183μm (IQR 148-252) initially, decreased significantly at month 2 (78μm (IQR 71-93) and further at month 4 (64μm (IQR 58-74) and 6 (61μm (IQR 52-81), Friedman test, p < 0.001). Initially, RNFT was above normal limits (due to swelling) in 15/16 patients; at month 2 it was below normal limits in 13/16 patients, at month 4 in 12/13 patients and at month 6 in 9/10 patients. 7/16 patients exhibited segmental swelling of the optic disc, whereas the entire circumference of the optic disc showed RNFL thickening in 9/16 patients. Functional deficits were present directly after onset of NAION and did not change relevantly further on. Morphological changes comprise severe swelling after onset of NAION, which rapidly turns into atrophy. Already after 2months more than 80% of the patients showed a RNFT below normal limits. Progressive RNFL thinning between month 2 and month 4 suggests ongoing atrophy, whereas a stable morphologic end point is reached after month 4.

Significance of Visual Evoked Potentials in the Assessment of Visual Field Defects in Primary Open-Angle Glaucoma: A Review

Visual evoked potentials is an important visual electrophysiological tool which has been used for the evaluation of visual field defects in primary open-angle glaucoma and is an appropriate objective measure of optic nerve function. Significant correlations between the magnitude of the VEP parameters and MD of Humphrey static perimetry suggest that the impaired visual cortical responses observed in glaucoma patients can be revealed by both electrophysiological and psychophysical methods. In addition, the severity of global glaucomatous damage evidenced by reduction in MD could depend on the delay in neural conduction from retina to the visual cortex as revealed by the significant correlation between VEP latencies and MD which also supports the validity of the VEP testing in progression of glaucoma.

Current electrophysiology in ophthalmology

To summarize current technique, indications, and pitfalls of electrophysiologic testing used in ophthalmology. Visual evoked potentials (VEPs) may be useful as an objective measurement of refractive error in complicated patients. VEP P100 latency was found superior to color vision and visual field in early stages of hydroxychloroquine maculopathy. VEP results can be predictive of visual recovery in traumatic optic neuropathy. Multifocal electroretinogram (ERG) or VEP can provide an objective assessment of visual field defects not yet present on automated perimetry in patients with glaucomatous and nonglaucomatous optic neuropathies. In patients with intraocular lymphoma, reduced amplitudes of all ERG components can be recorded, with the b-wave amplitude being most significantly affected. Various visual electrophysiologic tests are useful to the ophthalmologist, each with different indications. The flash ERG is most useful in diffuse retinal disorders, whereas the multifocal ERG is superior in localized retinal disease. VEPs can be valuable in diagnosing optic neuropathies, nonorganic visual loss, and assessing visual function in infants or children.

The Peritest, a new automatic and semi-automatic perimeter.

The Peritest is a new automatic and semi-automatic (manual) perimeter for detection and limited assessment of visual field defects. It uses either multiple or single stimulus static perimetry. The lightsources are LED's. A total of 206 positions can be examined including the center; 151 positions inside 25 degrees-eccentricity. The programmes use a threshold-related gradient adapted suprathreshold (0.6) strategy. The results are printed on a special chart using non-interpolated grey scales for indicating local reduction of sensitivity. General and local reduction of sensitivity are separated. The progress of the examination can be followed on a LED-monitor. The reliability of the patient is measured. 70% of small early glaucomatous defects (that are only found by high resolution meridional static perimetry) were detected. Such defects are not usually detected by routine kinetic perimetry. More peripheral defects were detected (greater than 25 degrees) than by kinetic perimetry. Due to the relatively high number of stimuli the typical configuration of defects was satisfactorily demonstrated for defects of moderate size and larger. The duration of the examination varies from less than 4 min. for a semi-automatic examination of normal eyes to 10-20 min. for automatic examination of eyes with defects of moderate size (average 15 minutes for 206 positions).

Die Bewertung von Augenschäden in der privaten Unfallversicherung

Together with a team from the HUK association (an association of liability, accident, transport and legal protection insurance-companies) the authors discussed a new assessment table for diminution of vision and have recommended its use by private accident insurance companies. The table was worked out on the basis of guidelines issued by the Deutsche Ophthalmologische Gesellschaft in 1981. In cases of bilateral eye damage the total extent of the disability - based on the specific diminution of usability of each eye - should be calculated according to the conditions of the insurance companies and not by a medical expert. Further proposals for the assessment of visual field defects and other kinds of eye damage covered by private accident insurance were also brought into line with the recommendations issued by the Deutsche Ophthalmologische Gesellschaft in 1981.

Clinical Experiences with the Use of an Automated Perimeter (Otopus) in the Diagnosis and Management of Patients With Glaucoma and Neurologic Diseases

This is a study of 59 patients, 42 with glaucoma and 17 with neurological disease, to compare the Octopus automated perimeter with the conventional Goldmann and Tubinger perimeters for detection and assessment of visual field defects. We believe the Octopus automated perimeter is an excellent method for screening patients suspected of glaucoma and can be expected to identify over 90% of the patients actually having visual field loss due to glaucoma. In patients with neurological disease, the Goldmann perimeter was superior to either the Octopus or Tubinger perimeters in providing clinically useful information.