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

Abstract

PurposeA newly developed head-mounted perimeter termed “imo” enables visual field (VF) testing without a fixed head position. Because the positional relationship between the subject’s head and the imo is fixed, the effects of head position changes on the test results are small compared with those obtained using a stationary perimeter. However, only ocular counter-roll (OCR) induced by head tilt might affect VF testing. To quantitatively reveal the effects of head tilt and OCR on the VF test results, we investigated the associations among the head-tilt angle, OCR amplitude and VF testing results.Subjects and methodsFor 20 healthy subjects, we binocularly recorded static OCR (s-OCR) while tilting the subject’s head at an arbitrary angle ranging from 0° to 60° rightward or leftward in 10° increments. By monitoring iris patterns, we evaluated the s-OCR amplitude. We also performed blind spot detection while tilting the subject’s head by an arbitrary angle ranging from 0° to 50° rightward or leftward in 10° increments to calculate the angle by which the blind spot rotates because of head tilt.ResultsThe association between s-OCR amplitude and head-tilt angle showed a sinusoidal relationship. In blind spot detection, the blind spot rotated to the opposite direction of the head tilt, and the association between the rotation angle of the blind spot and the head-tilt angle also showed a sinusoidal relationship. The rotation angle of the blind spot was strongly correlated with the s-OCR amplitude (R2≥0.94, p<0.0001). A head tilt greater than 20° with imo causes interference between adjacent test areas.ConclusionsBoth the s-OCR amplitude and the rotation angle of the blind spot were correlated with the head-tilt angle by sinusoidal regression. The rotated VF was correlated with the s-OCR amplitude. During perimetry using imo, the change in the subject’s head tilt should be limited to 20°.

<p>Comparison of head-mounted perimeter (imo^&reg;) and Humphrey Field Analyzer</p>

“…Finally, the issue of head tilt during examination with the i-H type must be considered, although the influence is reportedly small if tilting is within 20°. 25 The i-F type may prove to be better suited for use in cases where head tilt is prominent or the head-mounted device is felt to be heavy. In this context, the ability to select the most appropriate type of device is another advantage.…”

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

“…We tested VF testing with different gaze conditions using the imo perimeter (Fig. 3) as described previously [28][29][30][31] . Briefly, during an imo test, the target is presented to either eye using a full high-definition transmissive liquid crystal display and is backlit with a high-intensity light-emitting diode.…”

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

“…In 2015, a new portable head-mounted perimeter “imo” (CREWT Medical Systems, Tokyo, Japan) was released and is now commercially available. The basic structure and function of the imo have been reported by Matsumoto et al11 Moreover, several past publications have reported its features in detail 12–15. As the imo can perform testing in restricted spaces without a dark room, it has recently been used in clinical practice.…”

“…The basic structure and function of the imo have been reported by Matsumoto et al 11 Moreover, several past publications have reported its features in detail. [12][13][14][15] As the imo can perform testing in restricted spaces without a dark room, it has recently been used in clinical practice.…”