Effects of head tilt on visual field testing with a head-mounted perimeter imo

Head Turn During Visual Field Testing to Minimize the Influence of Prominent Facial Anatomy

BACKGROUND

Facial contour naturally decreases the visual field. Peripheral visual field defects caused by facial anatomy and ocular pathology can be missed in a routine standard of care. Mathematically calculating the true angle for turning the head to optimize the peripheral visual field has not been studied to date. The purpose of this study was to explore the utility of turning the head during perimetry to maximize the testable visual field.

METHODS

Six healthy study participants aged 18-52 were enrolled, prospectively; the dominant eye of each participant was tested. In total, 60-4 visual fields were obtained from each participant's dominant eye with the head in primary position. Then, the 60-4 tests were repeated with the head turned prescribed degrees toward and away from the tested eye ("manual method"). Based on a photograph of the participant's face, a convolutional neural network (CNN) was used to predict the optimal head turn angle for maximizing the field, and the test was repeated in this position ("automated method").

RESULTS

Maximal visual field exposure was found at a head turn of 15° away from the tested eye using the manual method and was found at an average head turn of 12.6° using the automated method; maximum threshold values were similar between manual and automated methods. The mean of threshold in these subjects at the standard direction and the predicted optimum direction was 1,302, SD = 69.35, and 1,404, SD = 67.37, respectively ( P = 0.02).

CONCLUSIONS

Turning the head during perimetry maximizes the testable field area by minimizing the influence of prominent facial anatomy. In addition, our CNN can accurately predict each individual's optimal angle of head turn for maximizing the visual field.

Comparison of the TEMPO binocular perimeter and Humphrey field analyzer

This study compared between TEMPO, a new binocular perimeter, with the Humphrey Field Analyzer (HFA). Patients were tested with both TEMPO 24-2 Ambient Interactive Zippy Estimated by Sequential Testing (AIZE)-Rapid and HFA 24-2 Swedish Interactive Threshold Algorithm (SITA)-Fast in a randomized sequence on the same day. Using a mixed-effects model, visual field (VF) parameters and reliability indices were compared. Retinal nerve fiber layer (RNFL) thickness was measured using Cirrus optical coherence tomography (OCT), and coefficient of determinations for VF and OCT parameters were calculated and compared using Akaike information criteria. 740 eyes (including 68 healthy, 262 glaucoma suspects, and 410 glaucoma) of 370 participants were evaluated. No significant differences were seen in mean deviation and visual field index between the two perimeters (P > 0.05). A stronger association between VF mean sensitivity (dB or 1/L) and circumpapillary RNFL was found for TEMPO (adjusted R2 = 0.25; Akaike information criteria [AIC] = 5235.5 for dB, and adjusted R2 = 0.29; AIC = 5200.8 for 1/L, respectively) compared to HFA (adjusted R2 = 0.22; AIC = 5263.9 for dB, and adjusted R2 = 0.22; AIC = 5262.7 for 1/L, respectively). Measurement time was faster for TEMPO compared to HFA (261 s vs. 429 s, P < 0.001). Further investigations are needed to assess the long-term monitoring potential of this binocular VF test.

Comparison of the TEMPO Binocular Perimeter and Humphrey Field Analyzer

This study compared between TEMPO, a new binocular perimeter, with the Humphrey Field Analyzer (HFA). Patients were tested with both TEMPO 24 - 2 AIZE-Rapid and HFA 24 - 2 SITA-Fast in a randomized sequence on the same day. Using a mixed-effects model, visual field (VF) parameters and reliability indices were compared. Retinal nerve fiber layer (RNFL) thickness was measured using Cirrus OCT, and coefficient of determinations for visual field and OCT parameters were calculated and compared using Akaike information criteria. 740 eyes (including 68 healthy, 262 glaucoma suspects, and 410 glaucoma) of 370 participants were evaluated. No significant differences were seen in mean deviation and visual field index between the two perimeters (P > 0.05). A stronger association between VF mean deviation and circumpapillary RNFL was found for TEMPO (adjusted R2 = 0.28; AIC = 5210.9) compared to HFA (adjusted R2 = 0.26; AIC = 5232.0). TEMPO had better reliability indices (fixation loss, false positive, and false negative) compared to HFA (all P < 0.05). Measurement time was faster for TEMPO compared to HFA (261sec vs. 429sec, P < 0.001). Further investigations are needed to assess the long-term monitoring potential of this binocular VF test.

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.

Gravity Influences How We Expect a Cursor to Move

We expect a cursor to move upwards when we push our computer mouse away. Do we expect it to move upwards on the screen, upwards with respect to our body, or upwards with respect to gravity? To find out, we asked participants to perform a simple task that involved guiding a cursor with a mouse. It took participants that were sitting upright longer to reach targets with the cursor if the screen was tilted, so not only directions on the screen are relevant. Tilted participants' performance was indistinguishable from that of upright participants when the screen was tilted slightly in the same direction. Thus, the screen's orientation with respect to both the body and gravity are relevant. Considering published estimates of the ocular counter-roll induced by head tilt, it is possible that participants actually expect the cursor to move in a certain direction on their retina.

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.

Age-dependent changes in visual sensitivity induced by moving fixation points in adduction and abduction using imo perimetry

Visual field (VF) testing has usually been performed with the central gaze as a fixed point. Recent publications indicated optic nerve head deformations induced by optic nerve traction force can promote the progression of optic neuropathies, including glaucoma. We generated a new static test protocol that adds 6° adduction and abduction to gaze position (fixation points) movement. The aim of this study was to investigate both whether quantifying VF sensitivities at lateral horizontal gaze positions is feasible and whether horizontal gaze positions change sensitivities differently in subjects of different ages. Healthy adult eyes from 29 younger (≤ 45 years) and 28 elderly (> 45 years) eyes were examined in this cross-sectional study. After VF testing with central gaze as a fixation point using 24 plus (1) imo static perimetry, subjects underwent VF testing with 6° adduction and 6° abduction as fixation points. The average mean sensitivities with central gaze, adduction, and abduction were 29.9 ± 1.0, 29.9 ± 1.3, and 30.0 ± 1.2 decibels (dB) in younger subjects and 27.7 ± 1.2, 27.5 ± 1.7, and 28.1 ± 1.3 dB in elderly subjects, respectively. Visual sensitivity in young healthy subjects was similar among the three fixation points, whereas visual sensitivity in elderly healthy subjects was significantly better with abduction as a fixation point than with central gaze and adduction (both p < 0.05). We expect this test protocol to contribute to our understanding of visual function during horizontal eye gaze movement in various eye diseases.

Comparison of central visual sensitivity between monocular and binocular testing in advanced glaucoma patients using imo perimetry

BACKGROUND/AIM

This study aimed to compare central visual sensitivity under monocular and binocular conditions in patients with glaucoma using the new imo static perimetry.

METHODS

Fifty-one consecutive eyes of 51 patients with open-angle glaucoma who were affected with at least one significant point in the central 10° were examined in this cross-sectional study. Monocular and binocular random single-eye tests were performed using the imo perimeter and the Humphrey field analyser (HFA) 24-2 and 10-2 tests. The eyes were assigned to 'better' and 'worse' categories based on the visual acuity and central visual thresholding. Central visual sensitivity results obtained by monocular, binocular random single-eye tests and binocular simultaneous both eye test were compared.

RESULTS

The average mean deviation with the HFA 24-2 was -5.5 (-1.5, -14.6) dB (median, (IQR)) in the better eyes and -18.0 (-12.9, -23.8) dB in the worse eyes. The mean sensitivity in the central 4 points of the visual field (VF) of the worse eyes was lower when measured under the binocular eye condition than under the monocular condition. Conversely, this value of the better eyes was greater when measured under the binocular eye condition than under the monocular condition.

CONCLUSIONS

The central sensitivity of the better eyes was better and that of the worse eyes poorer with binocular testing than with monocular testing in patients with glaucoma. Although monocular VF testing is still the most straightforward means to monocularly monitor glaucoma at clinical settings, binocular testing, such as provided with imo perimetry, may be a useful clinical tool to predict the effect of VF impairments on a patient's quality of visual life.

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.