Automatic (Octopus) and manual (Goldmann) perimetry in glaucoma

Childhood cerebral visual impairment subtype classification based on an extensive versus a limited test battery

Purpose

To classify CVI subtypes and compare the added value of an extensive test battery over a limited test battery in subtype classification of cerebral visual impairment (CVI) in children.

Methods

Seventy-five children with a clinical diagnosis of CVI (median [IQR] age: 9 [7-12] years) were identified from the medical records. The extensive test battery included visual acuity, contrast sensitivity, ocular alignment, eye movement analysis, visual field analysis, optic nerve head evaluation, and evaluation of visual perception. The limited test battery included visual acuity, contrast sensitivity, ocular alignment, and evaluation of visual perception. Principal component analysis (PCA) followed by cluster analysis was done, for both test batteries separately, to determine the optimum subtype classification for CVI.

Results

Fifty-one participants with an extensive test battery with mild to moderate visual impairment were included in the main analysis. This resulted in four CVI subtypes for the extensive test battery (subtle characteristics, higher-level visual function deficits, lower-level visual function deficits, and higher- and lower- level visual function deficits) and three CVI subtypes for the limited test battery (subtle characteristics, higher-level visual function deficits, and higher- and lower- level visual function deficits). There were significant differences between the subtypes for 9 out of 10 measures of the extensive and all 4 measures of the limited test battery (p < 0.05). The subtle characteristics subtype (extensive n = 19, limited n = 15) showed near normal lower and higher-level visual functions in both test batteries. The higher-level visual function deficits subtype (extensive n = 18, limited n = 24) showed near normal visual acuity combined with significant visual perceptual deficits in both test batteries; accompanied by visual pathways defects and abnormal eye movement behavior in the extensive test battery. The higher- and lower- level visual function deficits subtype (extensive n = 4, limited n = 12) showed both higher and lower-level visual function deficits in both test batteries, but application of the extensive test battery revealed additional visual pathways defects and abnormal eye movement behavior. The lower-level visual function deficits CVI subtype (extensive n = 10) was a new subtype identified by the extensive test battery. This subtype showed lower-level visual function deficits together with abnormal eye movement measures.

Conclusion

This data-driven study has provided meaningful CVI subtype classifications based on the outcomes of various key functional and structural measures in CVI diagnosis. Comparison of the extensive test battery to the limited test battery revealed the added value of an extensive test battery in classifying CVI. The outcomes of this study, therefore, have provided a new direction in the area of CVI classification.

A comparison of tangent screen, goldmann, and humphrey perimetry in the detection and localization of occipital lesions

OBJECTIVE

To compare manual kinetic perimetry with tangent screen and Goldmann techniques and automated static perimetry with the Humphrey Field Analyzer in the detection and localization of occipital lobe lesions.

DESIGN

Prospective consecutive comparative case series.

PARTICIPANTS

Twelve patients with well-defined occipital lobe infarcts on magnetic resonance (MR) imaging were studied.

MAIN OUTCOME MEASURES

The patients were tested by tangent screen, Goldmann, and Humphrey perimetry (central 30-2 threshold program). The three visual fields were compared and correlated with MR images.

RESULTS

All three perimetric techniques detected the presence of postchiasmal lesions. However, localization of lesions differed with perimetric technique. Visual fields obtained from tangent screen and Goldmann perimetry were similar and corresponded well with the location of lesions on MR images in all 12 patients. Humphrey perimetry inaccurately localized the lesion to the proximal part of the postchiasmal pathway by revealing incongruous fields in two patients, failed to detect sparing of the posterior occipital cortex or occipital pole in four patients, and estimated a larger extent of damage in one patient when compared with MR images and manual perimetry.

CONCLUSIONS

All three perimetric techniques are satisfactory screening tests to detect occipital lesions. However, tangent screen and Goldmann perimetry provide information about the location and extent of lesions that is more consistent with prevailing knowledge of the effects of the lesion in the postgeniculate visual pathway.

Temporal visual field in glaucoma: a re-evaluation in the automated perimetry era

We prospectively studied 152 glaucoma patients (192 eyes) and 31 normal subjects (31 eyes) tested with the 30-2 program and a customized temporal periphery program on the Humphrey Field Analyzer to determine the usefulness of routine testing temporal to the blind spot. We found that in 53 glaucomatous and each of 31 control eyes the central 30 degrees and temporal peripheral field were normal. In eyes with glaucomatous defects, testing temporal to the blind spot provided information equivalent to the central Bjerrum area in 66 eyes, less in 62 eyes, and more in 11 eyes. Temporal field testing was most useful in eyes with a diffusely depressed Bjerrum area (mean defect less than -8.30 dB). This study suggests that automated static perimetry commonly reveals glaucomatous defects temporal to the blind spot, but usually adds significant information over central testing only in patients with late visual field changes.

Computerized perimetry in glaucoma management

The present article discusses the role of computerized perimetry in the management of patients with suspect and manifest glaucoma. The value of visual field examination is compared to that of inspection and photography of the optic disc and to some extent to retinal nerve fibre layer photography. Computerized perimetry is related to standard manual visual field examination. Guidelines are offered for the choice of test programs and for the interpretation of results.

Full threshold versus quantification of defects for visual field testing in glaucoma

Nineteen glaucoma patients, 17 ocular hypertensives, and 16 normal subjects underwent visual field testing on the Humphrey Field Analyzer using two programs: full threshold (thresholding of all test points with double-crossing technique) and quantification of defects (thresholding only points that deviated more than 6 dB from a presumed normal retinal contour). The purpose of the study was to compare the diagnostic value of information gained by the latter, less time-consuming test with that of the full threshold procedure. The average time requirement per eye was 13 min 11 s for full thresholding and 4 min 22 s for quantification of defects. Of the 104 sets of fields, the diagnosis was at variance in 18. The differences were most often due to shallow defects in otherwise normal fields or shallow defects surrounding deeper scotomas that had been detected by both programs. The shallow defects placed the fields in more advanced diagnostic categories and were all detected with the full threshold technique.

Manipulation of sensitivity in visual field investigation

Sophistication of computer software and flexibility of stimulus and background luminance parameters in static perimeter design offer the opportunity for increased information in the assessment of the visual field. Relationships between dynamic ranges and resulting sensitivity gradients in a group of 10 normal 21 year old subjects using the Octopus automated perimeter, the Dicon Autoperimeter 2000 and the Friedmann VFA II are assessed. Inadequacies in the use of normative data to assess the visual field are noted. Implications for the use of dynamic range/sensitivity gradient relationships in visual field assessment without reliance on normative data are discussed.

The qualitative comparative analysis of the visual field using computer assisted, semi-automated and manual instrumentation: II. Statistical analysis

A comparative evaluation of the Octopus automated perimeter (Programmes 21 and 31), the Goldmann Bowl perimeter, the Bjerrum Screen and the Friedmann VFAs MkI and MkII was carried out on a heterogeneous sample of 75 patients. The results for the sample as a whole were analysed statistically in terms of the scoring system developed by Flanagan, Wild, Barnes, Gilmartin, Good and Crews (1984a). Statistically significant differences between the instruments were found at each of the 4 levels of analysis.

The frequency distribution of earliest glaucomatous visual field defects documented by automatic perimetry

2500-3000 eyes with ocular hypertension, with or without established glaucoma in the fellow eye, were followed with automatic perimetry for several years. Forty-five eyes showed a documented change from repeated normal fields to reproducible glaucomatous visual field loss. The location of the defective points in the first pathological field of each eye was registered. The resulting frequency distribution is shown and discussed.

Comparative material on automated and semiautomated perimeters-1983

In reviewing all the responses from the private practitioners and clinicians in Departments of Ophthalmology throughout the United States and Canada, it would appear that the majority of individuals are quite happy with the automated perimeters they have purchased. Clinicians should be aware that this is a rapidly changing field and several devices which were previously available are no longer being manufactured. In addition, because of the competition which has recently developed in the automated perimetry industry, prices are continuing to come down. Some practitioners have been unhappy with the fact they paid a higher price for a device which is currently selling at a lower price. However, a similar phenomenon has happened in the computer world and is to be expected as competition increases. The major problems which seem to be of concern to all ophthalmologists, are the difficulty in interpreting data and the management of the data. We believe one of the major frustrations of all practitioners using automated perimeters relates to the fact that this is a totally new technique, which requires time and practice to gain familiarity. In general, it would appear that most of the practitioners have been happy with the service provided by various companies, although there are a few exceptions. Read the enclosed responses and develop your own conclusions. We hope you find the information useful.

Effect of retinal nerve fibre loss on the optic nerve head configuration in early glaucoma

Twenty-nine ocular hypertensive patients with an optic disc haemorrhage, normal optic discs and normal visual fields were followed in this partly retrospective study by means of sequential optic disc stereophotographs and retinal nerve fibre layer (RNFL) photographs for a period of up to 14 years (mean 5.2). During this time early structural glaucoma damage developed in 11 patients (12 eyes). RNFL photographs revealed a nerve fibre loss in 10 of the 12 cases (83%). However, even accurate cup to disc ratio measurements from disc stereophotographs enlarged 20 times showed a measurable increase of horizontal and vertical cup to disc ratios in only 33% and 42% of the pathological cases, respectively. This result indicates that haemorrhage-associated RNFL defects precede measurable changes of the optic disc configuration. Therefore, RNFL photography seems to be a useful and sensitive examination method for the detection of the earliest organic damage in glaucoma.

Changes of glaucomatous field defects. Degree of accuracy of measurements with the automatic perimeter Octopus

The analytical programme Delta was used to determine longterm fluctuation and accuracy of measurement of the programme 31 of Octopus when used on glaucoma patients. Programme 31 examines the 30 degrees field. The test locations are arranged in a square grid with 6 degrees resolution. The programme Delta determines and compares 1) the disturbed area in %; 2) the total loss, the total sensitivity being around 2000 dB; 3) the loss in dB per mean number of disturbed points. Thirty-two eyes of 22 patients with established glaucomatous field defects were examined twice within two to six days and two months later again twice. The size of the disturbed area served for classification of our sample into three groups: 1st group: disturbed area 1-33%; 2nd group: disturbed area 34-66%; 3rd group: disturbed area 67-100%. Long-term fluctuations and accuracy of measurement could be determined as respectively follows: 1) Disturbed area between 0.7 +/- 8% in group 3 and 1.7 +/- 13% in group 2. 2) The total loss increases proportionately to the disturbed area and was 4.9 +/- 29.2 dB in group 1 and 31.8 +/- 82.4 dB in group 3. 3) The total loss per mean number of disturbed points was 0.5 +/- 2 dB in group 1 and 0.3 +/- 1.2 dB in group 2. This signifies that if the learning effect is over, changes of more than 2 dB, especially if several adjacent points are affected, are a significant loss. The learning effect, as determined in an earlier study, may go up as high as 2 dB per point.