Detection Of Visual Field Loss Research Articles

Objective detection of visual field defects with multifrequency VEPs.

To correlate multifrequency pattern reversal VEPs in quadrants (QmfrVEPs) with perimetric field losses for objective detection of visual field losses. QmfrVEP measurements were performed using four LED-based checkerboard stimulators to stimulate the four quadrants of the visual field. QmfrVEPs were measured monocularly in 5 normal subjects and in 5 glaucoma patients who showed losses in conventional Octopus perimetry. The pattern reversal frequency varied slightly between the stimulators: (11.92, 12.00, 12.08 and 12.16 reversals/sec). The responses to the different stimuli were identified by discrete Fourier analysis. VEPs were recorded using different electrode configurations, and the recording with the highest signal-to-noise ratio (SNR) was used for further analysis. QmfrVEP responses from the different quadrants can be reliably measured and separated using the 0.08 reversals/sec interstimulus reversal frequency differences. The signal-to-noise ratio in the four quadrants was significantly correlated with the equivalent visual field losses obtained with perimetry (Spearman rank correlation: P < 0.001). In the five glaucoma patients, the SNR was reduced in 15 out of the 16 quadrants with a perimetric defect, in comparison to the results in quadrants of healthy subjects. This confirms the sensitivity of the procedure. QmfrVEP responses can be measured reliably. This pilot study suggests that high SNR values exclude visual field defects and that focal defects can be identified in glaucoma patients. www. gov . NCT00494923.

Detection of post-stroke visual field loss by quantification of the retrogeniculate visual pathway

Visual field loss is associated with poor post-stroke functional outcomes. However, early detection of visual field loss is often challenging in patients with disabling stroke. This study explored the association between the microstructural integrity of the retrogeniculate pathway and visual field loss in disabling stroke patients undergoing inpatient rehabilitation. Thirty patients with stroke lesions involving the retrogeniculate visual pathway were included. The degree of visual field loss was determined by the visual field index and mean deviation using automated perimetry. The fractional anisotropy (FA) values were obtained for the lateral geniculate nucleus and optic radiation; the FA laterality indices, representing the degree of degeneration, were calculated. The FA values were compared between the affected and unaffected hemispheres. The patients were categorized into complete and incomplete hemianopia groups, and their FA values were compared. The relationship between the FA laterality index and the degree of visual field loss was assessed. FA values of the lateral geniculate nucleus and optic radiation were lower on the affected side than on the unaffected side (P < 0.001 and P < 0.001, respectively). The affected optic radiation in the complete hemianopia group showed a lower FA value than in the incomplete group (P = 0.006). The FA laterality index of the optic radiation was positively correlated with the degree of visual field loss (visual field index, ρ = 0.629; mean deviation, ρ = 0.568). The quantification of the retrogeniculate visual pathway may aid in detecting post-stroke visual field loss. The microstructural integrity of the optic radiation is associated with the severity of visual field loss.

Short-Listing the Program Choice for Perimetry in Neurological Conditions (PoPiN) Using Consensus Methods.

Background:Neurological conditions frequently cause visual field loss, commonly resulting in perimetry requests for suspected or known conditions. Currently there are no national guidelines for perimetry in neurological conditions. A wide choice of perimetry programs exists. An inappropriate program choice could fail to detect visual field loss. Two phases in this study determined preference of perimetry programs for detection of visual field loss in four common neurological conditions (idiopathic intracranial hypertension (IIH), optic neuropathies, chiasmal compression and stroke), to aid the design of research and clinical practice guidelines.Methods:A survey consisted of 47 perimetry programs. Orthoptists and neuro-ophthalmologists were asked which perimetry programs they considered important for use in the four neurological conditions. These programs were short-listed for discussion in a consensus meeting. A nominal group technique was used for the consensus meeting to reach consensus on the three most favoured perimetry programs appropriate for the four conditions.Results:Twenty-six participants completed the survey (51% return rate). Nine programs were found to be not applicable to any of the conditions. The short-lists for the conditions varied between six and ten perimetry programs. Seven participants discussed the survey results at a consensus meeting to agree the three most favoured perimetry programs for IIH, optic neuropathy and chiasmal compression (manual/semi manual kinetic, static 30–2 and full-field 120) and for stroke (manual/semi manual kinetic, static 30–2 and monocular Esterman).Conclusion:A wide range of perimetry programmes were explored thoroughly through survey and consensus methods in order to determine clinician preference for their use in neuro-ophthalmic practice. The three most favoured perimetry programs for the four conditions was established.

Detection of Visual Field Loss in Pituitary Disease: Peripheral Kinetic Versus Central Static

Visual field assessment is an important clinical evaluation for eye disease and neurological injury. We evaluated Octopus semi-automated kinetic peripheral perimetry (SKP) and Humphrey static automated central perimetry for detection of neurological visual field loss in patients with pituitary disease. We carried out a prospective cross-sectional diagnostic accuracy study comparing Humphrey central 30-2 SITA threshold programme with a screening protocol for SKP on Octopus perimetry. Humphrey 24-2 data were extracted from 30-2 results. Results were independently graded for presence/absence of field defect plus severity of defect. Fifty patients (100 eyes) were recruited (25 males and 25 females), with mean age of 52.4 years (SD = 15.7). Order of perimeter assessment (Humphrey/Octopus first) and order of eye tested (right/left first) were randomised. The 30-2 programme detected visual field loss in 85%, the 24-2 programme in 80%, and the Octopus combined kinetic/static strategy in 100% of eyes. Peripheral visual field loss was missed by central threshold assessment. Qualitative comparison of type of visual field defect demonstrated a match between Humphrey and Octopus results in 58%, with a match for severity of defect in 50%. Tests duration was 9.34 minutes (SD = 2.02) for Humphrey 30-2 versus 10.79 minutes (SD = 4.06) for Octopus perimetry. Octopus semi-automated kinetic perimetry was found to be superior to central static testing for detection of pituitary disease-related visual field loss. Where reliant on Humphrey central static perimetry, the 30-2 programme is recommended over the 24-2 programme. Where kinetic perimetry is available, this is preferable to central static programmes for increased detection of peripheral visual field loss.

Review of the Use of SWAP and FDT for the Early Detection of Visual Field Loss

Background: To review the literature reporting SWAP and FDT for the early detection of visual field loss in glaucoma. Methods: A review of literature publi shed on Medline, Scopus and Web of Science between 1966 and present was undertaken with only articles in the English language reviewed.

Validation of Testvision, an internet‐based test for the detection of visual field loss

AbstractPurpose The aim of the present study was to determine if the program Damato Testvision (DT), www.testvision.org, adequately detects visual field loss from glaucoma.Methods DT is available in three versions and was tested on 97 patients (188 eyes). The procedure was performed with a laptop connected to a computer monitor and a mouse placed on a height adjustable table. To determine sensitivity and specificity DT was compared to two gold standards: 1; Hodapp, Parrish and Anderson classification (Hodapp) of Humphrey 30:2 and 2; doctors' diagnoses.Results A total of 361 DT Standard tests were performed on 115 eyes. DT comparisons with Hodapp achieved sensitivity and specificity of 55% and 93% respectively when comparing no disease to early glaucomatous loss (AUC; 0,871). If early loss was merged with the no disease group, the sensitivity and specificity were 78% and 90% respectively (AUC; 0.931) Compared to the doctors' diagnosis DT achieved sensitivity and specificity of 52%; 96% respectively when borderline patients were classified in the glaucoma group (AUC; 0,867). If borderline patients were classified as controls: DT achieved sensitivity and specificity of 63%; 92% (AUC; 0,897).Conclusion Our study indicates that DT may be a promising tool to detect visual field defects in a pre‐selected population. The test is successful without prior training of the test person but minimal computer knowledge is advisable. The authors believe that internet based visual field examination may play a role as an easy accessible and affordable test. With further development, DT could be a tool for glaucoma screening in the home setting. Future studies need to evaluate DTs performance in the general population without prior selection.

Retinal nerve fibre layer attenuation: clinical indicator for vigabatrin toxicity

To investigate whether persistent visual field defects among patients exposed once to the antiepileptic drug vigabatrin (VGB) were associated with peripapillary retinal nerve fibre layer thickness (RNFLT) attenuation. Nine individuals with partial epilepsy and VGB-attributed visual field loss (group 1; 18 eyes) and seven age- and gender-matched individuals with epilepsy and no previous VGB exposure (group 2; 14 eyes) were included in the study. Full-field 120 point screening perimetry out to 60 degrees from central fixation using the Humphrey Field Analyzer was performed. RNFLT was quantified by optical coherence tomography (OCT) using Fast RNFLT protocol, Stratus OCT (3.0) after pupillary dilation. The results from the right eye are presented in this article. Among the patients with VGB-attributed visual field loss, five patients had only peripheral field defect (group 1a) and the remaining four had advanced field defects both in the periphery and within 30° from central fixation (group 1b). None of the patients in the control group had manifest visual field loss. The mean RNFLT among the patients with VGB-attributed visual field loss was significantly attenuated compared to the controls [mean total RNFLT: group 1: 75.6 ± 12.7 μm, group 2: 103.5 ± 9.7 μm, mean difference 27.9 μm, (CI 15.9-39.9; p < 0.001)]. RNFLT values classified as borderline according to normative database (Stratus OCT) occurred more frequently among individuals with VGB-attributed visual field loss than in controls (frequency in group 1: 6/9; group 2: 0/7, p = 0.011). The nasal, superior and inferior quadrants of RNFLT in individuals with VGB-attributed visual field loss were significantly attenuated, while no difference was detected in temporal quadrants compared to controls. Both individuals with peripheral and those with advanced visual field losses in the VGB group had attenuated mean total RNFLT compared to controls (p = 0.006, p = 0.002, respectively). Occurrence of borderline classification of total RNFLT ≤5th percentile was more frequent among individuals with advanced visual field loss than among controls (p = 0.048). Persistent visual field loss attributed to VGB is associated with reduced peripapillary RNFLT and was detected both among patients with advanced and among patients with only peripheral visual field defects. Measurements of RNFLT with OCT might be considered as a diagnostic supplement in the follow-up of patients exposed to vigabatrin.

Frequenzverdopplungsperimetrie

Glaucoma is a disease in which death of retinal ganglion cells is associated with loss of visual function. The gold standard for visual field testing has been standard automated perimetry (SAP). However, up to 30-50% of retinal ganglion cells must be lost before a scotoma is detected with SAP. Therefore, investigators have been interested in finding diagnostic techniques that would allow earlier detection of visual field loss than that detected by standard white-on-white perimetry. Frequency-doubling technology (FDT) has been suggested as a promising technique that may detect glaucomatous ganglion cell damage earlier than SAP by targeting a sparsely spaced subsystem of Mgamma retinal ganglion cells where cell damage is less masked by redundancy. The second generation of FDT perimetry, the Matrix FDT, was released with the intention of improving the spatial resolution of visual field defects. In this article we present FDT and discuss data that compare FDT with standard white-on-white perimetry.

Short-wavelength automated perimetry and retinal nerve fiber layer evaluation in suspected cases of glaucoma.

To determine if short-wavelength automated perimetry (SWAP) provides evidence that indicates early functional losses in ocular hypertensive subjects and to establish a direct comparison with early structural abnormalities in the retinal nerve fiber layer (RNFL). A total of 160 eyes belonging to 83 patients with ocular hypertension (intraocular pressure >21 mm Hg and normal results on standard automated perimetry evaluation), on which a SWAP and RNFL study were performed, were examined. One hundred twenty-eight age-matched subjects without ocular hypertension were evaluated to establish the 95% and 99% confidence intervals at each of the 76 exploration points of the SWAP test. The RNFL study results were normal in 83 cases (51.8%) and pathologic in 77 cases (48.1%). The SWAP results were pathologic in 57 cases (35.6%). Significant differences (P<.001) were observed when comparing the distribution of normal and pathologic SWAP results among the types of defects in the RNFL (focal wedge, diffuse atrophy, and mixed atrophy). Short-wavelength automated perimetry is a useful test for the early detection of visual field losses. It is more sensitive than standard automated perimetry and provides a high association with RNFL assessment, which has proved capable of detecting signs of glaucomatous damage several years before the onset of the typical visual field defects.

Factors influencing short wavelength automated perimetry in normal subjects

Background: Short wavelength automated perimetry (SWAP) has been shown to be useful in the early detection of visual field losses in glaucoma. This study investigates the effects of patient‐related variables on SWAP.Methods: Eight normal subjects performed SWAP under a range of refractive blur conditions (plano, +1.00 D, +2.00 D, +3.00 D) and filter conditions (0.3 neutral density, yellow).Results: The results of this study were:1 SWAP in normal subjects was unaffected by refractive blur up to +3.00D.2 Filters produced an overall depression in SWAP sensitivity results proportional to their 400 nm transmission.Conclusion: SWAP is a robust visual field test insensitive to moderate amounts of refractive error. However, as different visual mechanisms are being measured by the two tests, care should be taken when trying to compare SWAP directly with conventional white‐on‐white perimetry.

Morphologic Changes in the Lamina Cribrosa Correlated with Neural Loss in Open-Angle Glaucoma

We divided 25 glaucomatous human eyes into three groups representing mild (Group 1, seven eyes), moderate (Group 2, 11 eyes), and severe (Group 3, six eyes) optic nerve damage, based on visual field testing or remaining number of optic nerve fibers. The optic nerve head of each eye was examined by scanning electron microscopy. Compression of the successive lamina cribrosa sheets was the earliest detected abnormality, occurring in some eyes before the detection of visual field loss. Backward bowing of the entire lamina cribrosa was a later change and involved its upper and lower poles more than the mid-nerve head. The diameter of the scleral opening at the level of Bruch's membrane did not enlarge in these adult glaucomatous eyes. Mechanical compression of the nerve head occurred early enough to be considered a primary pathogenetic event in glaucomatous damage.

A Clinical Comparison of Three Computerized Automatic Perimeters in the Detection of Glaucoma Defects

The ability to detect glaucomatous field defects of three automatic computerized perimeters (COMPETER, OCTOPUS, and PERIMETRON) was compared in a clinical study of 74 patients. This study included patients with glaucoma, those with suspected glaucoma in whom the visual fields were completely normal, and normal subjects. The reference fields were obtained by careful static and kinetic manual perimetry on the Tübinger perimeter. All the automatic instruments gave similar high rates of detection of visual field loss and low false-positive test results. Quantity conventional manual perimetry is necessary to support automatic perimetric results, but automatic perimeters already can do a large proportion of routine perimetric screening.