Biomedical subjects

J M Nelson-Quigg

Publications and source records attributed to J M Nelson-Quigg.

5 recordsLinked to original sources

PubMed2000

Frequency doubling technology perimetry for detection of glaucomatous visual field loss.

PURPOSE: To evaluate the ability of frequency doubling technology perimetry to detect early, moderate, and advanced glaucomatous visual field loss. METHODS: In a prospective study, frequency doubling technology perimetry (C-20 full threshold) was performed in the right eye of 254 normal control subjects and 230 patients with early (n = 85), moderate (n = 114), or advanced (n = 31) glaucomatous visual field loss. Previous Humphrey Field Analyzer test results were used to classify glaucomatous visual field loss as early (mean deviation no worse than -6 dB), moderate (mean deviation between -6 and -12 dB) or advanced (mean deviation between -12 and -22 dB). RESULTS: Receiver operating characteristic curves showed 100% sensitivity and specificity (area under the curve, 1.0) for detecting advanced glaucomatous visual field loss, approximately 96% sensitivity and 96% specificity (area under the curve, 0.9751) for detecting moderate glaucomatous visual field loss, and approximately 85% sensitivity and 90% specificity (area under the curve, 0.9261) for early glaucomatous visual field loss. CONCLUSIONS: Frequency doubling technology perimetry demonstrates high sensitivity and specificity for detection of early, moderate, and advanced glaucomatous visual field loss.

Adolescent↗

PubMed2000

Predicting binocular visual field sensitivity from monocular visual field results.

PURPOSE: To compare methods of predicting binocular visual field sensitivity of patients with glaucoma from monocular visual field data. METHODS: Monocular and binocular visual fields were obtained for 111 patients with varying degrees of glaucomatous damage in one or both eyes, using the Humphrey 30-2 full-threshold procedure. Four binocular sensitivity prediction models were evaluated: BEST EYE, predictions based on individual values for the most sensitive eye, defined by mean deviation (MD); AVERAGE EYE, predictions based on the average sensitivity between eyes at each visual field location; BEST LOCATION, predictions based on the highest sensitivity between eyes at each visual field location; and BINOCUIAR SUMMATION, predictions based on binocular summation of sensitivity between eyes at each location. Differences between actual and predicted binocular sensitivities were calculated for each model. RESULTS: The average difference between predicted and actual binocular sensitivities was close to zero for the BINOCULAR SUMMATION and BEST LOCATION models, with 95% of all predictions being within +/-3 dB of actual binocular sensitivities. The best eye (MD) prediction had an average error of 1.5 dB (95% confidence limits [CL], +/-3.7 dB). The average eye prediction was the poorest, with an average error of 3.7 dB (95% CL, +/-4.6 dB). CONCLUSIONS: The BINOCULAR SUMMATION and BEST LOCATION models provided better predictions of binocular visual field sensitivity than the other two models, with a statistically significant difference in performance. The small difference in performance between the BINOCULAR SUMMATION and BEST LOCATION models was not statistically significant. For evaluations of functional visual field influences on task performance, daily activities, and related quality-of-life issues, either the BINOCULAR SUMMATION or BEST LOCATION model provides good estimates of binocular visual field sensitivity.

Glaucoma↗

PubMed1993

A prospective three-year study of response properties of normal subjects and patients during automated perimetry.

PURPOSE: The purpose of this study is to evaluate prospectively the reliability characteristics of patients undergoing automated perimetry over a 3-year period and compare these results with the results of previous investigations. METHODS: The subjects included 48 normal observers, 32 ocular hypertensive subjects, and 19 patients with early glaucomatous visual field loss. Both eyes were tested annually for 3 years with automated perimetry, using the standard procedures for the Humphrey Field Analyzer. Fixation losses, false-positive errors, false-negative errors, and short-term variability (double determinations) were evaluated. RESULTS: Short-term variability was slightly higher for the early glaucoma group than for the normal observer and ocular hypertensive groups, but there were no meaningful changes in short-term variability over 3 years. False-positive errors were very low in all three groups throughout the investigation. False-negative errors were slightly higher in the early glaucoma group, but all three groups had relatively low false-negative error rates throughout the study. Fixation losses were the most common source of unreliable results. The number of fixation losses decreased for the second and third years of the study. CONCLUSION: Contrary to a previous report, a relatively low number of unreliable tests were found for both initial and follow-up visits. The majority of unreliable visual field tests were sporadic events. Only a few subjects repeatedly produced unreliable test results. The authors conclude that automated perimetry can provide a reliable means of following patients over extended periods of time.

Adult↗

PubMed1993

Temporal modulation perimetry: the effects of aging and eccentricity on sensitivity in normals.

PURPOSE: Temporal modulation perimetry (TMP) is a new test procedure designed to measure sensitivity to sinusoidal flickering stimuli throughout the central 27 degrees visual field. The purpose of this investigation was to determine the effect of age and visual field eccentricity on temporal modulation sensitivity. METHOD: In its present form, TMP is used to determine modulation sensitivity for three temporal frequencies (2, 8, and 16 Hz) at 45 visual field locations. Both eyes of 43 normal observers between 20 and 75 years of age were examined. RESULTS: Our results indicate that sensitivity to all temporal frequencies tested showed a decline with age, particularly in the peripheral visual field. Furthermore, the age-related sensitivity loss was more pronounced for 16 Hz than for 2 or 8 Hz. CONCLUSIONS: These data demonstrate an age-related loss in temporal modulation sensitivity in the peripheral visual field. They also provide a baseline comparison standard for evaluation of clinical patient populations.

Adult↗

PubMed1989

Response properties of normal observers and patients during automated perimetry.

Automated perimetry was performed on both eyes of 54 normal subjects, 36 patients with ocular hypertension and normal visual fields, and 20 patients with early glaucomatous visual field loss to evaluate false-positive errors, false-negative errors, fixation losses, consistency of double determinations, and testing time. For all subject groups and response measures, large interindividual variation was found. No meaningful age-related changes were obtained for false-negative errors, false-positive errors, fixation losses, or consistency of double determinations. Contrary to earlier reports, we found a low number of normal subjects and patients exceeding the 33% false-positive and false-negative limits established for the Humphrey Field Analyzer. A large number of normal subjects and patients, however, exceeded the 20% limits for fixation losses.

Adult↗