Bilateral Concurrent Eye Examination with a Head-Mounted Perimeter for Diagnosing Functional Visual Loss

A case of functional visual loss diagnosed through bilateral randomized visual field testing with a trick method

Purpose

To report a case of functional visual loss (FVL) diagnosed through bilateral randomized visual field testing using Imo vifa with a trick method.

Observations

A 27-year-old man complained of visual field abnormality in his left eye after falling from a height of 4 m. The left eye had a best-corrected visual acuity (BCVA) of 20/16 and a critical flicker frequency (CFF) of 44.5 Hz at the first visit. Commotio retinae was observed in the inferior retina of the left eye, and the pupillary light reflex was normal. Computed tomography and magnetic resonance imaging of the head revealed no abnormalities. However, the Goldmann perimeter (GP) showed constriction of visual field in the left eye. Since traumatic optic neuropathy was suspected initially; therefore, two courses of methylprednisolone pulse therapy were administered. However, the BCVA and CFF gradually worsened to 20/200 and 14 Hz, respectively. Nevertheless, his pupillary light reflex was still normal, and GP showed a spiral visual field. Thus, we suspected that this was a case of FVL and performed bilateral randomized visual field testing using Imo vifa in three steps as a trick method. In the first step, we performed the normal method for bilateral randomized visual field testing. In the second and third steps, we explained to the patient that only the right or left eye would be examined on purpose; bilateral randomized visual field testing was then performed. The results of examinations revealed left homonymous hemianopsias and normal and concentric contraction of the visual field in both eyes. These results could not be explained by organic disease, and the patient was diagnosed with FVL.

Conclusions and Importance

Bilateral randomized visual field testing using Imo vifa with a trick method was useful for diagnosing FVL.

Test-retest repeatability of the imo binocular random single-eye test and Humphrey monocular test in patients with glaucoma

PURPOSE

To evaluate the reproducibility of the imo binocular random single-eye test (BRSET) and Humphrey Field Analyzer (HFA) monocular test in patients with glaucoma.

STUDY DESIGN

Retrospective observational study.

METHODS

We measured the visual fields (VF) of patients with glaucoma using the BRSET and HFA. All tests were repeated two months later. Mean sensitivity (MS), mean deviation (MD), sensitivity at each test location, and reliability indices were compared between the test days. Wilcoxon signed-rank test, interclass correlation coefficient (ICC), correlation coefficients, and Bland-Altman plots were generated for analysis.

RESULTS

We analyzed the VFs of 46 patients with glaucoma. There were no test-retest differences for MS and MD, and ICCs were > 0.9 for MS and MD in both perimeters. Inter-test correlations for MS and MD were high. The limits of agreement (LoAs) (lower, upper limit) between test days for MS were (- 3.4, 4.0) for BRSET and (-3.3, 3.0) for HFA. The LoA for MD was (- 3.3, 3.8) for BRSET and (- 3.2, 2.9) for HFA. Sensitivity at each testing location was more variable between testing days for BRSET than for HFA. For reliability indices, LoAs between testing days were wider for BRSET than for HFA.

CONCLUSION

The imo BRSET showed similar reproducibility to HFA in MS and MD. However, sensitivity at each test location varied more for BRSET than for HFA. Further studies are needed to verify the reproducibility of the imo BRSET.

Perimetric Comparison Between the IMOvifa and Humphrey Field Analyzer

PRCIS

IMO visual function analyzer (IMOvifa), a binocular perimeter, has similar output to the Humphrey Field Analyzer (HFA), but reduced the measurement time.

PURPOSE

The purpose of this study is to evaluate the performance of IMOvifa, a perimeter that performs binocular visual field (VF) testing, and to compare its results with standard automated perimetry.

METHODS

All patients underwent HFA 24-2 SITA-Fast and IMOvifa 24-2 AIZE-Rapid on the same day. Mean deviation (MD), pattern SD (PSD), foveal threshold, and visual field index (VFI) were compared between the 2 perimeters using Wilcoxon signed-rank tests, Pearson correlation, and Bland-Altman plot. Measurement time for performing VF for both eyes was also collected for each device.

RESULTS

In this cross-sectional study, 138 eyes (including 25 healthy, 48 glaucoma suspects, and 65 primary open angle glaucoma) of 69 patients were evaluated. Measurement time was significantly faster for IMOvifa compared with HFA (256 vs. 419 s, P <0.001). No significant differences were seen in MD and VFI between HFA and IMOvifa (both P >0.05). Significant differences were seen in mean PSD 3.2 (2.7, 3.6) dB for HFA versus 4.1 (3.5, 4.6) for IMOvifa ( P <0.001), and foveal threshold 33.9 (33.1, 34.6) dB for HFA versus 30.6 (29.3, 31.9) dB for IMOvifa ( P <0.001). Pearson r was strong for MD ( r =0.90, P <0.001), PSD ( r =0.78, P <0.001), and VFI ( r =0.94, P <0.001). The mean difference (95% limits of agreement) was -0.1 (-3.8, 3.5) dB for MD, -0.4 (-3.4, 2.5) dB for PSD, and 0.1 (-8.9, 9.1) dB for VFI, respectively.

CONCLUSIONS

IMOvifa reduced measurement time by 39%. MD, PSD, and VFI values for IMOvifa showed good agreement with HFA SITA-Fast strategy. This perimeter reduced fatigue for both patient and examiner. Additional studies are needed to determine whether it will be useful for routine VF testing.

Agreement in the detection of chiasmal and postchiasmal visual field defects between imo binocular random single-eye test and Humphrey monocular test

PURPOSE

To compare the ability of imo binocular random single-eye test (BRSET) to detect visual field (VF) defects due to chiasmal and postchiasmal lesions (C/PCLs) with a Humphrey Field Analyzer (HFA) monocular test.

STUDY DESIGN

Prospective multicenter study METHODS: This study enrolled 40 patients with C/PCLs and measured their VFs using both imo BRSET and HFA monocular test. The VFs were classified into three groups using the cluster criterion: 1) bitemporal group, 2) homonymous group, and 3) others. The agreement and correlation of VF results between imo and HFA were analyzed using the Bland-Altman plot and Spearman correlation coefficient.

RESULTS

The VFs of 34 patients were analyzed and classified. There were 13 patients in the bitemporal, 6 in the homonymous, and 15 in the others group. BRSET showed a significantly shorter test duration than HFA. The imo systematically yielded a lower sensitivity than HFA. The average sensitivity at each test location correlated well between the perimeters in all groups, with the correlation coefficients ranging from 0.89 to 0.98. Bland-Altman plots showed wider limits of agreement in the affected quadrants compared to the unaffected quadrants in the bitemporal and homonymous groups. The fixation loss rate did not differ between the perimeters, but there were significant differences in the false positive and false negative rates between perimeters.

CONCLUSION

BRSET detected VF defects due to C/PCLs as accurately as the HFA monocular test with a shorter test duration.

Comparison of imo and Humphrey field analyzer perimeters in glaucomatous eyes

AIM

To compare the imo perimeter, a new portable head-mounted perimeter unit that enables both eyes to be examined quickly and simultaneously, with the Humphrey field analyzer (HFA) perimeter to investigate correlations and their diagnostic ability in glaucomatous eyes.

METHODS

The performance of the equipment in 128 glaucomatous eyes and 40 normal eyes were tested. We investigated the correlations of mean deviation, pattern standard deviation, visual field index, and the sensitivity.

RESULTS

Measurements of mean deviation (r=0.886, P<0.001), pattern standard deviation (r=0.814, P<0.001), and visual field index (r=0.871, P<0.001) in both perimeters were strongly and positively correlated. The sensitivities in the imo perimeter were 80.5% for mean deviation, 81.2% for pattern standard deviation, and 80.5% in visual field index; those in the HFA were 63.3% for mean deviation, 74.5% for pattern standard deviation, and 80.5% for visual field index. Both perimeters demonstrated high diagnostic ability.

CONCLUSION

The parameters by the imo and HFA in glaucomatous eyes show strong positive correlations with favorable sensitivity, specificity, and diagnostic ability. However, the difference between imo and HFA results increases with the increase in visual field disturbance.

Central Visual Field Sensitivity With and Without Background Light Given to the Nontested Fellow Eye in Glaucoma Patients

PRECIS

This study showed the difference of monocular visual sensitivity between with and without background light given to the nontested fellow eyes in glaucoma patients. Monocular sensitivity measurements of the worse eyes with fellow eye's background light conditions should carefully be considered when assessing the impact of functional impairment in glaucoma patients.

PURPOSE

The purpose of this study was to investigate the difference between monocular sensitivities measured with and without background light given to the nontested fellow eye in glaucoma patients using a new perimeter named "imo."

METHODS

In this cross-sectional study, we examined 102 eyes of 51 patients (mean age, 65.1±14.9 y) with open-angle glaucoma who were affected with at least 1 significant point in the central 10 degrees. We conducted a routine ophthalmic examination and visual field testing using the Humphrey Field Analyzer 24-2 and 10-2 programs. The eyes were assigned to "better" and "worse" categories based on the visual acuity and central visual thresholding. Subsequently, we compared the central visual sensitivities with and without background light given to the nontested fellow eye.

RESULTS

The mean sensitivity (MS) in the central 5 points of the visual field of the worse eyes was better when measured with background light than without background light (P=0.037) given to the nontested fellow eye. No significant difference was seen among the MS in the visual field of the better eyes. After dividing the patients into low (n=25) and high sensitivity (n=26) groups, only the low sensitivity group in worse eyes had higher MS with background light than without background light (P<0.05) given to the nontested fellow eye.

CONCLUSIONS

Monocular sensitivities measured with background light given to the nontested fellow eye were higher than those without background light in the worse eye group of glaucoma patients. Monocular MS measurements of the worse eyes with fellow eye's background light conditions and their related indices should thus carefully be considered when assessing the impact of functional impairment in glaucoma patients.

Comparison of head-mounted perimeter (imo®) and Humphrey Field Analyzer

Purpose

The head-mounted automated perimeter imo^® is a new portable perimeter that does not require a dark room and can be used to examine patients in any setting. In this study, imo 24plus (1-2) AIZE examinations were compared with previous Humphrey Field Analyzer (HFA) 30-2 (SITA standard) examinations within the same patient.

Patients and methods

imo examinations (either head-mounted [i-H] or fixed [i-F] type) were performed in patients with glaucoma or suspected glaucoma who had already experienced HFA five or more times. Measurement time and correlations of mean deviation (MD) and visual field index (VFI) values were compared between groups for HFA, i-H, i-F, and imo total (i-T). Fixation loss (FL), false-positive (FP), and false-negative (FN) detection rates were compared. The percentage of binocular random single-eye tests under possible non-occlusion conditions using imo was determined. Mann–Whitney U test was performed, and Spearman’s rank-order correlation coefficient was calculated.

Results

The inclusion period was July to December 2016. Among 273 subjects (543 eyes), 147 (292 eyes) were tested with i-H type and 126 (251 eyes) with i-F type. Mean MD values for HFA and i-T were -6.1±7.8 and -6.2±7.1 dB, respectively. Mean measurement times for HFA, i-H, i-F, and i-T were 15.23±2.07, 10.47±2.11, 11.04±2.31, and 10.54±2.19 minutes, respectively (P<0.01 for HFA vs i-H/i-F). Total mean measurement time was shorter by 30.8% for i-T vs HFA. Correlation coefficients of MD and VFI were R²>0.81 for HFA vs i-H and i-F. FP and FN detection rates were significantly higher with i-T than HFA; there was no significant difference in FL. Binocular random single-eye tests were possible in 85% of cases.

Conclusion

imo reduced measurement time by 30.8%. imo VFI and MD values were highly correlated with HFA. As i-F and i-H types produced similar results, imo can be used in accordance with the patient’s situation.

Comparison of monocular sensitivities measured with and without occlusion using the head-mounted perimeter imo

Purpose

Using a head-mounted perimeter imo that can measure monocular sensitivity with both eyes open, we investigated the difference between monocular sensitivities measured with and without occlusion of the fellow eye and if the difference was influenced by eccentricity.

Methods

Using the perimeter imo, monocular sensitivities with/without occlusion and binocular sensitivity were measured and compared. Three test conditions for monocular sensitivity without occlusion were: with/without a fusional fixation target, and a binocular random single eye test in which the target was randomly presented to either eye and the examinee was not aware of the tested eye. Within the central 25° visual field (VF), 29 points located at the fovea and on the 45°, 135°, 225°, and 315° meridians with 3° intervals were tested. Differences among the four monocular sensitivities with/without occlusion were further evaluated at the fovea, within and beyond the central 5° VF.

Results

Sixteen visually normal volunteers (mean age, 28.6 ± 4.6 years) were included in this study. Except at the fovea, monocular sensitivities measured without occlusion were significantly higher than those with occlusion (P < 0.01). No significant difference was seen among the three monocular sensitivities without occlusion (P = 0.82).

Conclusions

Except at the fovea, monocular sensitivities measured with and without occlusion significantly differed. This indicates that without occlusion, binocular interaction is activated and affects not only binocular sensitivity but also monocular sensitivity.

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.

Variability in monocular and binocular fixation during standard automated perimetry

The aim of this cross-sectional study was to use standard automated perimetry to compare fixation variability among the dominant eye fixation, non-dominant eye fixation, and binocular fixation conditions. Thirty-five eyes of 35 healthy young participants underwent standard automated perimetry (Humphrey 24–2 SITA-Standard) in dominant eye fixation, non-dominant eye fixation, and binocular fixation conditions. Fixation variability during foveal threshold and visual field measurement, which was recorded using a wearable eye-tracking glass and calculated using the bivariate contour ellipse area (deg²), was compared among the three fixation conditions. Further, the association of bivariate contour ellipse area with ocular position and fusional amplitude during binocular fixation was analysed. There were no significant differences in bivariate contour ellipse area during foveal threshold measurement among the dominant eye fixation (1.75 deg²), non-dominant eye fixation (1.45 deg²), and binocular fixation (1.62 deg²) conditions. In contrast, the bivariate contour ellipse area during visual field measurement in binocular fixation (2.85 deg²) was significantly lower than the bivariate contour ellipse area in dominant eye fixation (4.62 deg²; p = 0.0227) and non-dominant eye fixation (5.24 deg²; p = 0.0006) conditions. There was no significant difference in bivariate contour ellipse area during visual field measurement between dominant eye fixation and non-dominant eye fixation conditions. There was no significant correlation between bivariate contour ellipse area and either ocular position or fusional amplitude during both foveal threshold and visual field measurements. Thus, fixation variability might be improved in binocular fixation conditions during a long-duration test, such as visual field measurement.