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Pictures of upright and inverted faces were unilaterally presented in either the left or right visual field. Subsequent recognition performance was found to be superior for faces falling in the left visual field regardless of orientation. The results are discussed in relation to Yin's (1970) ideas concerning a face-specific recognition system located in the right hemisphere.
PURPOSE: The authors studied the effects of trabeculectomy on the time course of central 30 degrees visual field performances in progressive normal-tension glaucoma (NTG). METHODS: Patients with NTG who had clear ocular media and were adequate performers on the 30-2 program of Humphrey Perimeter were prospectively followed with periodic field testing. Trabeculectomy using an antimetabolite was indicated when the slope of a line fitted to the time course of the mean deviation (MD), MD slope, was significantly negative. The time courses of MD and mean of total deviations (mean TD) in four subfields, superior and inferior arcuate and superior and inferior cecocentral fields, were analyzed using the mixed linear model. RESULTS: In progressive NTG, 21 eyes of 21 cases with postoperative follow-up of 2 years or more, intraocular pressure averaged 16 mmHg, MD averaged -13.5 dB, and MD slope averaged -1.48 dB/year preoperatively; 2 years after surgery, they averaged 9.2 mmHg, -13.6 dB, and +0.13 dB/year, respectively. Trabeculectomy had a significant beneficial effect on the time course of MD and mean TD in the superior and inferior arcuate and superior cecocentral fields, which showed significant preoperative deterioration. The mean TD in the inferior cecocentral field showed no significant time change during the period studied. CONCLUSION: For patients with NTG in whom the MD slope is significantly negative, trabeculectomy may have beneficial and diffuse effects on further deterioration of the visual field.
PURPOSE: To compare the relationship between sensitivity and response variability in the visual field of normal eyes and eyes with optic neuritis (ON), glaucoma (POAG), and ocular hypertension (OHT). METHODS: Frequency-of-seeing (FOS) data were collected from four visual field locations in one eye of 71 subjects (12 ON, 25 POAG, 11 OHT, and 23 normal), using a constant stimulus method on an Henson 4000 perimeter (Tinsley Instruments, Croydon, UK). At each location, at least 20 stimuli (subtending 0.5 degrees) were presented for 200 ms at six or more intensities above and below the estimated threshold. The mean and SD of the probit fitted cumulative Normal function were used to estimate sensitivity and response variability. Cluster regression analysis was carried out to determine whether there were differences in the sensitivity-log (variability) relationship between the four groups. RESULTS: Variability was found to increase with decreased sensitivity for all four groups. The combined data from the four groups was well represented (R2 = 0.57) by the function log(e)(SD) = A.sensitivity (dB) + B, where the constants A and B were -0.081 (SE, +/-0.005) and 3.27 (SE, +/-0.15), respectively. Including other statistically significant covariates (false-negative errors, P = 0.004) and factors (diagnosis, P = 0.005) into the model increased the proportion of explained variance to 62% (R2 = 0.62). Stimulus eccentricity (P = 0.34), patient age (P = 0.33), fixation loss rate (P = 0.10), and false-positive rate (P = 0.66) did not reach statistical significance as additional predictors of response variability. CONCLUSIONS: The relationship between response variability and sensitivity is similar for ON, POAG, OHT, and normal eyes. These results provide supporting evidence for the hypothesis that response variability is dependent on functional ganglion cell density.
We evaluated the relevance of interocular asymmetry of optic disc size to the level of intraocular pressure and the extent of optic disc and visual field changes in normal-tension glaucoma (NTG). Fifty-two eyes of 26 patients with NTG were measured for optic disc topography using a computerized image analysis system (IMAGEnet, Topcon), diurnal intraocular pressure (IOP), and Octopus automated visual field. Of the 26 patients, 22 had interocular asymmetry of the optic disc area of at least 0.01 mm2 and of mean IOP of at least 0.3 mmHg. Of these 22 patients, 8 had the higher mean IOP in the eye with the larger optic disc. In these 8 patients, the visual field defect was significantly more advanced in the eye with the larger optic disc (Wilcoxon signed ranks test, P < 0.05). These findings appear to support the hypothesis that an eye with a large optic disc may be more vulnerable to a rise in IOP.
OBJECTIVES: To compare the severity, size, and depth of glaucomatous visual field defects using standard full threshold (FT), Swedish interactive threshold algorithm (SITA) standard (SS), and SITA fast (SF) algorithms of the Humphrey perimeter. METHODS: A prospective observational case series of 77 patients with glaucoma performed FT, SS, and SF 30-2 white-on-white testing programs on the same day on 2 occasions for 1 month. The severity of defects was compared using the mean deviation, pattern standard deviation, Advanced Glaucoma Intervention Study, and Hodapp-Anderson-Parrish severity scores. The sizes of defects were compared using the total number of abnormal points on the pattern deviation plot that fit standard criteria for glaucomatous visual field defects. The depths of the defects were compared using the sum of the threshold values for points identified in the pattern deviation plot as fitting criteria for glaucomatous defects. RESULTS: The mean deviations were slightly better using the SS (-9.6 +/- 7.1 dB) or the SF (-9.1 +/- 6.7 dB) algorithm compared with the FT algorithm (-10.3 +/- 7.1 dB) (P<.005). There were no significant differences in pattern standard deviations between SS (8.6 +/- 4.0, P =.08) and SF (8.1 +/- 3.6, P =.19) compared with FT (8.3 +/- 3.3), although the pattern standard deviation was higher in SS fields compared with SF fields (P<.001). Advanced Glaucoma Intervention Study scores were slightly better when the SS (7.5 +/- 5.6) or SF (7.2 +/- 5.4) algorithm was used compared with the FT algorithm (8.6 +/- 5.4) (P<.001). The sizes of glaucomatous defects were slightly larger using the SS (20.9 +/- 10.7) algorithm compared with the FT algorithm (19.2 +/- 10.9) (P =.004) but not the SF algorithm (20.0 +/- 10.6) (P =.11). The depth of defects measured by the SS (220.4 +/- 108.0 dB) and SF (219.8 +/- 101.3 dB) algorithms was significantly shallower compared with that measured by the FT algorithm (152.3 +/- 79.1 dB) (P<.001). There were no significant differences in Hodapp-Anderson-Parrish severity scores among algorithms (P =.12). CONCLUSIONS: Glaucomatous defects are measured significantly shallower using the new SITA algorithms but are approximately the same size and severity compared with FT measurements. Care should be taken when using threshold values to compare glaucomatous defects in a patient when converting from FT to SITA algorithms.
A group of 55 patients with homonymous field defects related to vascular or traumatic postgeniculate damage were trained by locating light targets presented within their blind field region. This systematic treatment led, in the majority of patients, to an enlargement of the visual field. Recovery depended on specific practice. Control experiments showed that field enlargement cannot be explained by eccentric fixation or perimetric measurement variability. It is hypothesized that recovery may take place at striate cortex level and may result from 'reactivation' of reversibly damaged nervous tissue. In cases that did not benefit from treatment, visual field loss may result from irreversible damage.
We present a case report of suspected retinal malignant melanoma that was followed up with a threshold sensitivity visual field test. The correlation between computerized visual fields as used in proving retinal function disabilities and other tumor-growth diagnostic tools is discussed.
Sergent (Brain 113, 537-568, 1990) flashed pairs of digits to the opposite visual fields of three commissurotomized subjects (L.B., N.G. and A.A.), and found that they were highly accurate in deciding which digit was the larger, but at little or no better than chance in deciding whether the digits were the same or different. Experiment 1 confirmed that these subjects were better at relative than at same-different judgements. However their performance on relative judgements was considerably lower than in Sergent's study and could be explained largely in terms of the subjects' use of information available to a single hemisphere. A fourth subject, D.K., with section of the posterior corpus callosum only, had little difficulty with either task despite previous evidence of visual disconnection, and appeared able to transfer the information verbally. In Experiment 2, L.B. was better able to make both relative and same-different judgements when the digits were presented within either the left or right visual fields than when they were presented in opposite fields. These results suggest little, if any, interhemispheric transfer of either shape or numerical information following complete forebrain commissurotomy.
In the study of variables which may affect peripheral visual perception are several ways of assessing deterioration of this perception. One is evaluation of deformation of the useful visual field. Two techniques of analysis have been considered, by calculation of deformation indices, as proposed by Rantanen in 2003 and by carrying out an elliptical interpolation from the location within the visual field of signals perceived by a subject. This latter means, proposed by Rogé in 2002, enables description of whole field with the aid of two parameters. Comparison of the two techniques clarifies their advantages and disadvantages.
PURPOSE: The Swedish Interactive Thresholding Algorithm (SITA) is a new testing strategy for the Humphrey perimeter. The standard SITA algorithm shortens test time in adults without increasing variability, but its usefulness for detecting field defects in children has not been investigated. METHODS: We evaluated 92 standard SITA 24-2 visual fields of children, most of whom had various types of optic neuropathies (pediatric idiopathic intracranial hypertension, homonymous defects, bitemporal defects, papilledema from brain tumors), and compared them with 49 full threshold 24-2 fields obtained in similar patients. We evaluated outcome measures of foveal threshold, mean defect, pattern standard deviation, false-negative and false-positive rates, and test time. Five children (9 eyes) had both SITA and full threshold testing (FTT). RESULTS: The SITA decreased test time by over 50% compared with FTT (12.6 +/- 3.0 minutes vs 6.6 +/- 1.6 minutes [P <.00001]). When patients with field defects were eliminated, the pattern standard deviation was lower with SITA than FTT (P <.002), indicating lower intratest variability of SITA in subjects with normal fields. No detectable difference was observed in the other outcome measures. Subjective analysis of gray-scale fields in patients who underwent testing with the use of both strategies showed marked similarities. CONCLUSIONS: SITA shortens test time significantly compared with FTT and does so without jeopardizing interpretability. SITA has less intratest variability than FTT and therefore should be better for detecting and following defects. Caution is advised when following a visual field defect unless the same strategy is used for each evaluation. Switching strategies in the absence of a stable field defect is not recommended.
Automated perimetry has decreased the subjective aspects of data collection, but analysis has remained largely subjective. A microcomputer permits more objective analysis by regrouping and averaging data points in the threshold static visual field according to their retinotopic projection onto the optic disc rather than according to their eccentricity from the point of fixation. The applications of the technique include (1) following glaucomatous visual field loss, (2) differentiating glaucomatous from other forms of visual loss, and (3) studying the effects of aging on the visual field. Six formulas for data analysis are described, and their relative usefulness discussed. Percent loss or gain seemed to convey the most diagnostic information to the clinician. Percent of expected sensitivity was less than the decimal visual acuity when the diagnosis was glaucoma but greater when the diagnosis was cataract. In some cases this analytic method should provide information that could favorably affect patient management.
PURPOSE: To extract unidimensional, well-separated latent scores that are anatomically and clinically valid from 52 standardized variables collected by Humphrey visual field (VF) perimetry (Carl Zeiss Meditec, Dublin, CA). METHODS: Visual field data of 437 patients were collected and classified by a glaucoma specialist into seven clinical groups: irregularities of VF (IVF), nasal step (NaS), arcuate scotoma (AC), paracentral scotoma (PCS), blind-spot enlargement (BSE), diffuse deficit (DD), and advanced deficit (AD). The number and content of constituent variable scores were identified by principal components analysis followed by Varimax Rotation and simple clustering, taking spatial distribution homogeneity and visual system anatomy into account. Unidimensionality was checked by a stepwise Cronbach alpha curve. Clinical predictability of the derived scores was checked by comparing clinical groups (ANOVA). RESULTS: Patients older than 60 years comprised 53.3% of the sample. The average mean deviation was -9.2 dB and pattern standard deviation was 6.5 dB. Six scores were identified: four peripheral scores (nasal superior, NS; nasal inferior, NI; temporal superior, TS; and temporal inferior, TI) and two paracentral scores (PCSs; superior, PCSS; and inferior, PCSI). Cronbach alpha was always >0.90. The six scores decreased sequentially from IVF to DD to AD. Scores of AC were lower in NS, NI, and TS; PCSS was less in PCS; BSE scores were less in TS and TI; NaS scores were less in NS and NI. CONCLUSIONS: Six well-separated, optimal scores were obtained from the Humphrey perimetry matrix. Internal reliability was good. It was possible to discriminate between clinical subgroups. Further analyses, based on longitudinal data, must be performed to confirm these findings.
Perceptual asymmetries have been explained by structural, attentional bias and attentional advantage models. Structural models focus on asymmetries in the physical access information has to the hemispheres, whereas attentional models focus on asymmetries in the operation of attentional processes. A series of experiments was conducted to assess the contribution of attentional mechanisms to the right visual field (RVF) advantage found for word recognition. Valid, invalid and neutral peripheral cues were presented at a variety of stimulus onset asynchronies to manipulate spatial attention. Results indicated a significant RVF advantage and cueing effect. The effect of the cue was stronger for the left visual field than the RVF. This interaction supports the attentional advantage model which suggests that the left hemisphere requires less attention to process words. The attentional asymmetry is interpreted in terms of the different word processing styles used by the left and right hemispheres. These results have ramifications for the methodology used in divided visual field research and the interpretation of this research.
PURPOSE: To characterize the visual fields of subjects with migraine headaches using static and temporal modulation perimetry. METHODS: Sixteen subjects with migraines (15 with aura, 1 without) and 15 nonheadache controls were tested. Perimetry was conducted 7 days after the offset of a headache with both static and temporally modulated targets using the Medmont M-600 automated perimeter (Medmont Pty Ltd., Camberwell, Victoria, Australia). Flicker thresholds were measured using the autoflicker test, which varies flicker rate with eccentricity. A subset of four subjects with migraines (3 with aura, 1 without) had the temporal tuning characteristics of their loss evaluated using fixed temporal frequencies (4, 6, 9, 12, and 16 Hz). RESULTS: Field losses were identified with temporal modulation perimetry in 11 of 16 migraine subjects. The majority of these losses occurred in the presence of normal static thresholds (8/11). The deficits displayed temporal tuning, being greatest for higher temporal frequencies (> or =9 Hz). None of the subjects revealed deficits typical of cortical lesions. The migraine-without-aura subject displayed a selective loss to temporally modulated stimuli, which was consistent with the aura group. This defect altered over time, decreasing for 30 to 40 days but remaining, to a smaller extent, for up to 75 days after the headache event. CONCLUSIONS: Visual dysfunction that is selective for temporally modulated targets occurs in migraine subjects. The migrainous pattern of dysfunction shares some features with that identified in early stages of glaucoma and raises the possibility for a common precortical vascular involvement in these two conditions.
The binocular visual field of the pigeon, measured ophthalmoscopically, is ovoid in shape. It is 114 degrees in vertical extent and centered and widest (37 degrees) about the eye-beak axis (i.e. the line passing through the straight edge of the beak and the midpoint of a line connecting the centres of the pupils). The area dorsalis projects 10 degrees-15 degrees below the eye-beak axis where the field is 35 degrees wide. The stereotyped peck response of the pigeon entails birds pausing twice. At the first fixation, the image of a grain is on the area dorsalis and at the final fixation the grain is centered within the widest part of the binocular field.
OBJECTIVE: To examine the effects of the gold standard on sensitivity, specificity, and area under the ROC curve when determining the validity of a screening test. METHODS: Fifty-eight people were recruited from a Veterans' Administration eye clinic. Screening included testing with the 26-point oculokinetic perimeter (OKP). We used different gold standards to categorize patients as positive or negative for glaucoma. The glaucoma hemifield test (GHT) and corrected pattern standard deviation (CPSD) from the Humphrey visual field analyzer (HVF) were used as objective gold standards. Ophthalmologist review of the HVF, using two different methods for classifying visual field defects, was also used as a gold standard. RESULTS: Using the review of the HVF that included mild, moderate, or severe defects, the area under the ROC curve was not significantly different from 50%. However, for all the other gold standards, the area under the ROC curve was significantly different from 50%. CONCLUSIONS: In determining the ability of the OKP to differentiate between glaucoma and normal subjects, the choice of a gold standard led to different conclusions about its usefulness as a screening test for glaucoma. Furthermore, sensitivity and specificity varied widely depending on which gold standard was used, and what cutoff point was used for the OKP. Although clinician review of the HVF may be used when specific criteria are given to define visual field defects, using objective measures from the HVF is easier and will allow for better comparisons between studies.
In a prospective, randomized, double-masked study, primary open-angle glaucoma patients were treated twice daily with either betaxolol 0.5% or timolol 0.5%. Patients received a pretreatment baseline examination following a 2 week washout period; they were then examined after 3 and 6 months of treatment. Each examination included visual field measurements with an Octopus automated perimeter and intraocular pressure measurement. The visual fields of the betaxolol group showed on the average a pronounced tendency toward improvement (MD decrease of 2.05 dB); visual fields in the timolol group showed a slight tendency toward improvement (MD decrease of 1.56 dB). The difference between these 2 trends after 6 months was statistically not significant (p greater than or equal to 0.05, U-test). Both drugs lowered intraocular pressure, there was no significant difference between the two drugs (p greater than or equal to 0.05, U-test).
OBJECTIVE: To determine whether blue-on-yellow perimetry reveals progression of glaucomatous damage before it is evident with standard white-on-white perimetry. DESIGN: A Humphrey field analyzer (Humphrey Instruments, San Leandro, Calif) was modified to perform blue-on-yellow perimetry to isolate and measure the sensitivity of short wavelength-sensitive mechanisms. Participants were tested annually with standard white-on-white automated perimetry and blue-on-yellow automated perimetry for 5 years. PATIENTS: Sixteen patients with early glaucomatous visual field loss in one or both eyes and 62 age-matched normal control subjects. RESULTS: At baseline, 25 (78.1%) of the 32 eyes exhibited larger deficits with blue-on-yellow perimetry, five (15.6%) had equivalent loss with both tests, and two (6.3%) had larger deficits with standard white-on-white perimetry. Seven (21.9%) of the 32 eyes demonstrated evidence of progressive visual field loss with standard white-on-white perimetry in 5 years, while the other 25 eyes (78.1%) were relatively stable. Deficits with blue-on-yellow perimetry were twice as large as deficits with white-on-white perimetry in the stable group and were three to four times as large in the group with progressive field loss. CONCLUSIONS: Blue-on-yellow perimetry is effective in predicting which patients with early glaucomatous visual field loss are most likely to have progressive loss. The rate of progressive loss is greater with blue-on-yellow perimetry than with standard white-on-white perimetry.