New approach for the glaucoma detection with pupil perimetry

Effects of Stimulus Luminance, Stimulus Color and Intra-Stimulus Color Contrast on Visual Field Mapping in Neurologically Impaired Adults Using Flicker Pupil Perimetry

Purpose

We improve pupillary responses and diagnostic performance of flicker pupil perimetry through alterations in global and local color contrast and luminance contrast in adult patients suffering from visual field defects due to cerebral visual impairment (CVI).

Methods

Two experiments were conducted on patients with CVI (Experiment 1: 19 subjects, age M and SD 57.9 ± 14.0; Experiment 2: 16 subjects, age M and SD 57.3 ± 14.7) suffering from absolute homonymous visual field (VF) defects. We altered global color contrast (stimuli consisted of white, yellow, cyan and yellow-equiluminant-to-cyan colored wedges) in Experiment 1, and we manipulated luminance and local color contrast with bright and dark yellow and multicolor wedges in a 2-by-2 design in Experiment 2. Stimuli consecutively flickered across 44 stimulus locations within the inner 60 degrees of the VF and were offset to a contrasting (opponency colored) dark background. Pupil perimetry results were compared to standard automated perimetry (SAP) to assess diagnostic accuracy.

Results

A bright stimulus with global color contrast using yellow (p= 0.009) or white (p= 0.006) evoked strongest pupillary responses as opposed to stimuli containing local color contrast and lower brightness. Diagnostic accuracy, however, was similar across global color contrast conditions in Experiment 1 (p= 0.27) and decreased when local color contrast and less luminance contrast was introduced in Experiment 2 (p= 0.02). The bright yellow condition resulted in highest performance (AUC M = 0.85 ± 0.10, Mdn = 0.85).

Conclusion

Pupillary responses and pupil perimetry's diagnostic accuracy both benefit from high luminance contrast and global but not local color contrast.

P100 Wave Latency and Amplitude in Visual Evoked Potential Records in Different Visual Quadrants of Normal Individuals

Purpose

Assessment of the pattern visual evoked potential (PVEP) responses in different areas of visual fields in individuals with normal vision.

Methods

This study was conducted on 80 eyes of normal subjects aged 18-35 years. All participants underwent refraction and visual acuity examination. Visual evoked potential (VEP) responses were recorded in different areas of field. The repeated measure test was used to compare the P100 latency and amplitude of PVEP among different areas.

Results

The repeated measures analysis of variance showed a statistically significant difference among different areas in terms of amplitude and latency of P100 (P = 0.002 and P < 0.001, respectively). According to the results, the highest and lowest amplitude of P100 was observed in inferior-nasal and superior areas, respectively. The highest and lowest latency of P100 was related to the temporal and inferior-nasal areas, respectively.

Conclusion

This study partially revealed the details of local PVEP distribution in the visual field and there was a significant difference in the amplitude and latency of PVEP wave in different areas of the visual field.

Evaluation of Pupil Fields Using a Newly Developed Perimeter in Glaucoma Patients

PURPOSE

To evaluate objective pupil fields using a newly developed perimeter for the detection of glaucomatous damage.

MATERIALS AND METHODS

Forty-three eyes of 32 glaucoma patients (42-69 years) were examined. Glaucomatous eyes were classified into three stages using the Hodapp-Anderson-Parrish grading scale (early, 16; moderate, 14; and severe, 13 eyes). The head-mounted perimeter "imo" was used to measure the percentage pupil constriction (PPC) of the pupil fields at 36 test points. A stimulus target size of Goldmann V with 0 decibels (dB) light under 31.4 apostilbs (asb) background was presented. Visual fields were measured with the Humphrey Field Analyzer 10-2 program. Using the 3D OCT-2000, 10 × 10 grid of the macular thickness were also obtained. Median correlation coefficients (r) of each examined eye were analyzed between the PPC and visual field sensitivity (dB), and the thickness of the retinal nerve fiber layer (RNFL), ganglion cell layer (GCL)⁺ (GCL + inner plexiform layer [IPL]), and GCL⁺⁺ (RNFL + GCL + IPL), respectively.

RESULTS

Moderate correlations between the PPC and dB (r = 0.44-0.55), and GCL⁺⁺ (r = 0.43-0.45) were obtained in the correspondence analysis of 12 test points. There were no significant differences in glaucoma severity (P = 0.924-1.000). However, some patients with extremely early stage glaucoma (visual field index ≥90%) tended to have poor correlation.

CONCLUSIONS

Pupil fields of the imo generally corresponded to the visual fields and the RNFL + GCL + IPL thickness, even in early glaucoma; however, the examiner must clearly understand the criteria of patient selection.

Chromatic Multifocal Pupillometer for Objective Perimetry and Diagnosis of Patients with Retinitis Pigmentosa

PURPOSE

To assess visual field (VF) defects and retinal function objectively in healthy participants and patients with retinitis pigmentosa (RP) using a chromatic multifocal pupillometer.

DESIGN

Cross-sectional study.

PARTICIPANTS

The right eyes of 16 healthy participants and 13 RP patients.

METHODS

Pupil responses to red and blue light (peak, 485 and 625 nm, respectively) presented by 76 light-emitting diodes, 1.8-mm spot size at different locations of a 16.2° VF were recorded. Subjective VFs of RP patients were determined using chromatic dark-adapted Goldmann VFs (CDA-GVFs). Six healthy participants underwent 2 pupillometer examinations to determine test-retest reliability.

MAIN OUTCOME MEASURES

Three parameters of pupil contraction were determined automatically: percentage of change of pupil size (PPC), maximum contraction velocity (MCV; in pixels per second), and latency of MCV (LMCV; in seconds). The fraction of functional VF was determined by CDA-GVF.

RESULTS

In healthy participants, higher PPC and MCV were measured in response to blue compared with red light. The LMCV in response to blue light was relatively constant throughout the VF. Healthy participants demonstrated higher PPC and MCV and shorter LMCV in central compared with peripheral test points in response to red light. Test-retest correlation coefficients were 0.7 for PPC and 0.5 for MCV. In RP patients, test point in which the PPC and MCV were lower than 4 standard errors from the mean of healthy participants correlated with areas that were indicated as nonseeing by CDA-GVF. The mean absolute deviation in LMCV parameter in response to the red light between different test point was significantly higher in RP patients (range, 0.16-0.47) than in healthy participants (range, 0.02-0.16; P < 0.0001) and indicated its usefulness as a diagnostic tool with high sensitivity and specificity (area under the receiver operating characteristic curve (AUC), 0.97, Mann-Whitney-Wilcoxon analysis). Randomly reducing the number of test points to a total of 15 points did not significantly reduce the AUC in RP diagnosis based on this parameter.

CONCLUSIONS

This study demonstrates the feasibility of using a chromatic multifocal pupillometer for objective diagnosis of RP and assessment of VF defects.

Accuracy of pupil assessment for the detection of glaucoma: a systematic review and meta-analysis

OBJECTIVE

To assess the accuracy of using pupillary light reflex (PLR) in detecting glaucoma.

CLINICAL RELEVANCE

Glaucoma is a specific disease of the optic nerve and is often more severe in 1 eye. When large enough, this asymmetry in disease severity can cause a relative afferent pupillary defect (RAPD). Better detection of RAPDs may be one way to identify persons with glaucoma.

METHODS

We searched Medline and Embase through June 2012 and searched bibliographies for relevant studies for additional references. Two authors independently reviewed all articles and selected studies that assessed PLRs in patients with glaucoma. We analyzed data using mixed-effect bivariate summary receiver operating characteristic meta-analysis models.

RESULTS

A total of 30 studies were included in this review. An RAPD was observed in 9% to 82% of patients with glaucoma. Eleven studies with a total of 7271 participants were included in the analysis, and the pooled estimate corresponded to a sensitivity of 0.63 (95% confidence interval [CI], 0.43-0.80) and a specificity of 0.93 (95% CI, 0.85-0.97). After excluding 2 studies that used the swinging flashlight test, the sensitivity increased to 0.74 (95% CI, 0.59-0.85) with a specificity of 0.85 (95% CI, 0.77-0.90). Study designs and different pupil measurement techniques explained part of the heterogeneity between studies.

CONCLUSIONS

Patients with glaucoma frequently have an abnormal PLR and comparing the responses between the 2 eyes can in part distinguish between those with glaucoma and those without the disease. Newer instruments and analytic approaches to assess pupil function may improve the performance of pupil screening.

A history of perimetry and visual field testing

Perimetry and visual field testing have been used as clinical ophthalmic diagnostic tools for many years, and this manuscript will provide a brief historical overview of these procedures and the individuals who developed them. Today, we have many different forms of perimetry that are designed to evaluate different locations within the visual pathways and various mechanisms and subsets of mechanisms within the visual system. However, the most widely used method of performing perimetry and visual field testing has not substantially changed for more than 150 years, consisting of detecting a small target superimposed on a uniform background at different locations within the field of view. Although the basic test procedure has remained similar throughout the ages, there have been many advances in test administration, standardization, statistical evaluation, clinical analysis, interpretation, and prediction of outcome based on visual field findings.