Variability in patients with glaucomatous visual field damage is reduced using size V stimuli.

PURPOSE: To test the hypothesis that variability of conventional automated perimetry can be reduced using size V stimuli for patients with glaucomatous visual field damage. METHODS: Ten patients with glaucoma and five age-matched control volunteers were tested with the Humphrey Field Analyzer program 24-2 or 30-2, after which the method of constant stimuli was used to measure frequency-of-seeing curves. This was done by controlling the perimeter with a custom program run by a personal computer. At two widely separated visual field locations on the program 24-2 or 30-2 grid, stimuli were presented in 2 dB intervals to at least 10 dB on either side of the estimated program 24-2 or 30-2 threshold. This protocol was performed for each of three stimulus sizes (Goldmann sizes I, III, and V). For the patients with glaucoma, one test location was chosen in an area of normal visual field sensitivity, the other in an area of 10 to 20 dB loss. Control subjects were tested at the (3 degrees, 3 degrees) and (-21 degrees, -9 degrees) test locations. Fifteen repetitions were performed at each intensity. RESULTS: Repeated measures analysis of variance showed that variability, as measured by the standard deviation of the cumulative Gaussian function of the fitted frequency-of-seeing curves, was lowest at the abnormal sensitivity test location in the subjects with glaucoma using a size V stimulus. Differences between the results from the V to III and V to I stimuli were statistically significant (size V = 2.9 dB, III = 10.1 dB, I = 10.1 dB). The same trend in estimated standard deviations was present in tests of the area of normal sensitivity (size V = 1.1 dB, III = 1.7 dB, I = 2.0 dB) in subjects with glaucoma and for the control subjects' peripheral test locations, but not for the central location. The smaller reduction in variability between estimated standard deviations of the size I and size III stimuli was not statistically significant at any test location. CONCLUSIONS: Use of size V stimuli in conventional automated perimetry reduces variability in tests of moderately damaged and normal sensitivity test locations in subjects with glaucoma.

Effect of instructions on conventional automated perimetry.

PURPOSE: To investigate the effect of perimetrists' instructions on automated perimetry thresholds. METHODS: Eighteen volunteers in two age groups participated in a series of three test sessions. Each session consisted of a Humphrey Field Analyzer 30-2 test, a questionnaire, and a customized test program using a Humphrey perimeter to construct frequency of seeing (FOS) curves from which thresholds were calculated, and a descriptive measure of response criterion was derived. The FOS curves were obtained at a central and a peripheral test location within the same test session. The three test sessions differed only by the instructions given. The instructions were adapted from those listed in the manufacturer's instruction manual and were designed to influence participants to respond to the stimuli in a conservative, liberal, or neutral manner. RESULTS: For the 30-2 threshold test, a significant difference in mean deviation was found among the three instruction types (P = 0.001) and between the two age groups (P = 0.001). Although differences were small in the younger subjects (2.04 dB), the means for the responses from liberal to conservative differed by 6.57 dB in the older subjects. Thresholds obtained in a peripheral location by the customized threshold test were found to differ significantly between the age groups (younger group mean, 31.0 dB; older group mean, 27.2 dB) and among the instruction types (liberal mean, 30.9 dB; conservative mean, 28.1 dB; and neutral mean, 30.3 dB; P < 0.001). The descriptive measurement of response criterion suggests that a difference in criteria occurred as a result of the instructions in both peripheral and central locations for both age groups (P = 0.0001). In addition, according to self-reports, liberal instructions caused participants to be more likely to respond, whereas the conservative instructions caused them to be more reluctant to respond. CONCLUSIONS: Perimetrists' instructions can significantly affect obtained automated perimetry thresholds.

Long- and short-term variability of automated perimetry results in patients with optic neuritis and healthy subjects.

OBJECTIVE: To measure the short- and long-term variability of automated perimetry in patients with optic neuritis and normal subjects. DESIGN: Prospective case-control design of patients with recovered optic neuritis with intraday and interday repetitions to obtain robust variability measurements. Entry criteria included a corrected pattern SD that was worse than the normal 5% probability level and a mean deviation worse than -3 dB but better than -20 dB. Five Humphrey 30-2 full threshold tests were administered during a 7-hour period (1 test every 2 hours) on the same day and at the same periods on 5 separate days. SUBJECTS: Seventeen patients with recovered optic neuritis and 10 healthy subjects of similar age. MAIN OUTCOME MEASURES: Short-term variability and long-term variability for global visual field data. RESULTS: Patients with optic neuritis demonstrated variations in visual field sensitivity that were outside the entire range of variability for normal controls. These variations occurred for multiple tests performed on the same day at specific times and for tests performed at specific times on different days. There were no consistent patterns of sensitivity changes that could be attributed to time of day. The most dramatic fluctuations occurred in a patient whose visual fields varied from normal to a hemianopic defect from one week to another and from a partial quadrant loss to a hemianopic defect at different times on the same day. Seven of the patients with optic neuritis also demonstrated intermittent vertical step defects. CONCLUSIONS: Patients with resolved optic neuritis can have large variations in visual field results on different days and at different times on the same day. The variations affect both the severity and the pattern of visual field loss and do not appear to be consistent across patients. These data indicate that care must be taken when automated visual field results in patients with optic neuritis are interpreted. Distinguishing systematic changes in sensitivity from variability requires more than a comparison of the current visual field with the most recent previous visual field.

Automated perimetry in amblyopia: a generalized depression.

PURPOSE: To quantitate the visual field abnormalities associated with amblyopia. METHODS: In a prospective study, 37 amblyopic patients (11 anisometropic, 13 strabismic, 9 combination, 4 deprivation) performed automated perimetry in each eye using the Humphrey 30-2 program. Primary outcome measures were foveal threshold, mean deviation, and average threshold. RESULTS: When the probability plots were examined, 21 visual fields in amblyopic eyes were normal, 8 had central scotomas, and 7 had diffuse depressions. No focal defects other than mild central scotomas were seen. However, the foveal threshold of amblyopic eyes was decreased by an average of 7.2 +/- 8.0 dB (P < .0001) compared with fellow eyes; intereye differences in mean deviation (3.2 +/- 5.4 dB; P < .001) and average threshold (2.9 +/- 5.3 dB; P < .005) were also seen. This decrease in sensitivity for the amblyopic eye occurred for all types of amblyopia. The depression in threshold was greatest at the fovea but was detectable and significant at all eccentricities of the 30-degree field. The average threshold in the amblyopic eye was highly correlated with visual acuity (r = .839; P < .001). CONCLUSIONS: Although automated visual fields in amblyopic eyes typically appear normal, all four types of amblyopia are associated with a generalized depression of light sensitivity, which is proportionately greatest at the fovea and highly correlated with visual acuity loss. In general, amblyopia is not associated with any area of focal loss of threshold light sensitivity. If a focal defect is present in the visual field of the amblyopic eye, organic causes of visual loss should be suspected. The Humphrey visual field analyzer STATPAC program (Allergan-Humphrey, Inc, San Leandro, California) may artifactually transform small and generalized full-field depressions in a manner that makes them appear to be isolated central defects.

Bone mineral density in grand multiparous women with extended lactation.

OBJECTIVE: We sought to assess whether the accumulation of multiple, frequent pregnancies and the accompanying repeated extended lactation events was a risk factor for low bone mineral density and osteoporosis. STUDY DESIGN: The study population consisted of 30 grand multiparous women who had borne at least 6 children and lactated for at least 6 months with each child, as well as 6 nulliparous, premenopausal women from a population of Finnish American women associated with the Laestadian Church in Washington State. The Church membership has not embraced contraception or extensive bottle-feeding, resulting in a group of women who are either pregnant or lactating during most of their adult reproductive lives. The medical history included the delivery date, birth outcome, infant birth weight, and number of months lactated for each pregnancy, as well as other health information. Bone mineral density of the lumbar spine, femoral neck, and radius was measured with the Hologic QDR 4500-C dual-energy x-ray absorptiometry scanner. Proc Genmod, SAS version 6.14 (Statistical Analysis Systems, Inc, Cary, NC), was used to perform a Wilcoxon test for a nonparametric analysis of covariance and significance adjusted for age and body size. RESULTS: The 2 study groups did not differ in terms of body mass index, history of smoking, or family history of osteoporosis and fracture, although the parous group was, on average, 8 years older than the nulliparous group (P <.05). The accumulation of repeated pregnancy and lactation events without a recovery interval was not associated with lowered bone mineral density or the presence of osteoporosis or osteopenia. CONCLUSIONS: This study suggests that bone mineral density levels can be sustained in the presence of the rapidly changing hormone environment associated with multiple pregnancies accompanying lactation events without a "recovery" interval.