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Visual Field Assessment (visual + field_assessment)

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Medical Sciences	100%

Selected Abstracts

Visual field assessment and the Austroads driving standard

CLINICAL & EXPERIMENTAL OPHTHALMOLOGY, Issue 1 2002
Isabel M McLean MB BS
Abstract Purpose:,To compare the conventional (Humphrey 24-2) automated visual field testing with the Goldmann standard visual field test for driving, and to predict how many patients with glaucoma may not meet the Australian driving standard with respect to visual fields. Methods: Four patients (retinitis pigmentosa, glaucoma or vigabatrin treatment) with marked visual field defects as determined by uniocular static computerized perimetry (conventional testing) were re-evaluated with binocular kinetic Goldmann IV4e target field test (Australian driving standard). A series of 48 consecutive patients seen by the Glaucoma Inheritance Study in Tasmania were assessed with both static computerized perimetry and the Goldmann IV4e target test. Results:,The four patients with severe visual field defects (on computerized perimetry) were found to meet the driving standard on the binocular Goldmann IV4e target test. On computerized perimetry, 15 of 48 patients from the Glaucoma Inheritance Study in Tasmania were found to have visual field defects of sufficient severity that they may not meet the driving standard. However, only five of these patients failed the driving standard for visual fields, two of whom were still driving. Conclusions:,Patients with severe field defects on conventional uniocular automated perimetry may still meet the Goldmann standard visual field test for driving. Approximately 30% of glaucoma patients would have visual field loss shown on Humphrey 24-2 test of a severity that requires further testing to determine if they meet the driving standard. Ten per cent of glaucoma patients tested did not meet the driving standard for visual fields. [source]

Tilted disc syndrome may mimic false visual field deterioration

ACTA OPHTHALMOLOGICA, Issue 6 2008
Marja-Liisa Vuori
Abstract. Purpose:, Tilted disc syndrome is a congenital anomaly of the eye characterized by mostly upper temporal visual field defects. The aim of the present study was to evaluate the effect of gradual myopic correction in the improvement of visual field defects associated with tilted disc syndrome. Methods:, The visual field was examined in 38 eyes of 24 patients using standard Goldmann perimetry. The isoptres IV-4e, I-4e, I-3e and I-2e were plotted. The defective isoptres were tested again with gradually increasing myopic correction until no further change was noted. Results:, The most common type of defect was a relative upper temporal defect (19 eyes). Temporal relative defects were found in five eyes, upper altitudinal field defects in six eyes, an enlarged blind spot in four eyes, and an inferior field defect in one eye. The visual field defect partly or totally disappeared with increased myopic correction in 18 (50%) eyes. The mean improvement was 17.0 ± 6.2 degrees and the mean additional myopic correction was 3.1 ± 1.5 D. Conclusions:, Even a small change in near correction during visual field examination may imply worsened or improved visual field defects in tilted disc syndrome. To prevent a false interpretation of field deterioration in a patient with tilted disc syndrome and glaucoma, visual field assessment should include examination with the myopic correction that provides the maximal improvement of the defective visual field. [source]

CASE REPORT: Clinical application of mfERG/VEP in assessing superior altitudinal hemifield loss

CLINICAL AND EXPERIMENTAL OPTOMETRY, Issue 4 2005
Dr Henry Ho-lung Chan PhD FAAO
Multifocal ERG (mfERG) and multifocal VEP (mfVEP) have been used widely in the investigation of pathological changes or functional variations in the visual system. Altitudinal hemifield loss is a visual field defect that is usually found in patients with ischaemic optic neuropathy (ION). Anterior ischaemic optic neuropathy (AION) is a complex multi-factorial disease and it is difficult to diagnose according to clinical symptoms and signs alone. AION is believed to be caused by an infarction of the optic nerve due to the occlusion of the posterior ciliary arteries. The current report presents a patient diagnosed with non-arteritic AION. In this report, the mfERG findings did not match the results of the visual field test but those of the mfVEP did. After consideration of the visual electrophysiological and visual field results, the defect arises from neither the retina nor the visual pathway behind the optic chiasma. Hence, the optic nerve is the most likely location of the lesion, causing the superior altitudinal hemi-field loss. This report shows that the mfERG and mfVEP techniques can be used for objective visual field assessment to supplement the conventional visual field testing. [source]

Clinical application of the multifocal visual evoked potential

CLINICAL AND EXPERIMENTAL OPTOMETRY, Issue 3 2004
David P. Crewther PhD
Background: Measures of visual function thresholds such as visual acuity and visual fields are generally dependent on subjective responses and assume maintenance of fixation, attention and motivation. In the young, elderly, cognitively impaired or malingering populations, such measures may be inaccurate or difficult to obtain. The Visual Evoked Response Imaging System (VERIS) has been claimed to give more objective topographic recordings of retinal and cortical function. This paper aims to explore the adequacy of this technique in four unusual, unrelated, clinically difficult cases. Methods: Multifocal visual evoked potentials (mfVEPs) recorded on the VERIS System 3.01 are used to assess visual function in four cases with contradictory clinical findings or unreliable subjective responses. Results: Patient 1 had sustained a head injury and had normal ocular and pupil examination but light perception in the right eye and 6/5 acuity in the left. Multifocal VEPs showed a marked depression of the right visual field with little macular response. Patient 2 had sustained a head injury, had a left field hemianopia, possible macular sparing and loss of much of the right field, reduced but variable visual acuities, good near vision and normal ocular fundi. Multifocal VEPs showed a severe depression in both visual fields (L more than R) with little macular response. Patient 3 had a left optic nerve meningioma and experienced great difficulty with visual field assessment. mfVEPs showed a bilateral depression in the superior field particularly the left field, with a larger deficit in the left eye. Patient 4 had unexplained visual acuity and peripheral field deficits. mfVEP results were inconclusive in this case. Discussion: Where there is difficulty performing traditional techniques or conflicting clinical findings, mfVEPs may provide additional objective information to aid in the assessment of patients. [source]