Is the RAPDx Pupillograph Able to Distinguish Between Glaucoma Subjects and Healthy Subjects?

RAPDx Pupillography for Early Detection of Glaucoma

The Konan RAPDx (Konan Medical USA, Irvine, CA) is a newly patented pupillography device.The aims of this study are to assess the ability of the RAPDx to distinguish between healthy subjects and patients with confirmed glaucoma using standard testing sequences developed for use at the Wills Eye Hospital Glaucoma Research Center and to determine the combination of demographic, clinical, and RAPDx testing parameters which allow for maximum sensitivity and specificity.

The RAPDx utilizes noninvasive digital, high-definition, infrared machine-vision with eye-tracking and automated blink detection technology to analyze and quantify the pupillary response to light.

During the scheduled appointment, all patients will receive an undilated fundus examination by the attending ophthalmologist. The following data will be collected; Demographic information, Visual acuity, Intraocular pressure (IOP) measured by Goldmann applanation tonometry, Disc damage likelihood scale (DDLS), Vertical cup/disc ratio, Gonioscopy (if not documented in the chart within the past 2 years) and Humphrey visual field examination.

Each participant will undergo RAPDx testing with two different testing sequences. They are separated by a 10-second resting period during which the patient is instructed to close his or her eyes. The exam may be paused at any time and re-alignment may be performed during any pause. The two testing sequences are:

1. Standard Factory Setting: 0.1-second stimuli with 2-second inter-stimuli pauses;
2. Custom Setting: 3-second stimuli with 1-second inter-stimuli pauses

Inclusion Criteria:

Glaucoma patients:

• optic nerve damage (neuroretinal rim notch, asymmetric inter-eye cup to disc (c/d_ ratio >0.2 or disc damage likelihood scale (DDLS) >2, or absence of neuroretinal rim not due to other cause)
• glaucomatous visual field (VF) deficits (cluster of 3 or more points on pattern deviation plot depressed below 5% level, at least 1 depressed below 1% level; OR corrected pattern standard deviation/pattern standard deviation significant at P <0.05; or glaucoma hemifield test "outside normal limits") with good reliability indices (fixation losses, false-positive rate, false-negative rate each < 33%).

Healthy subjects:

• normal optic nerve exam
• normal reliable VF (Humphrey mean deviation (MD) >-2 or Octopus MD ≤0.8; fixation losses, false-positive rate, and false-negative rate each < 33%)
• open angles gonioscopy.

Exclusion Criteria:

• Abnormal ocular motility preventing binocular fixation (e.g. strabismus, nystagmus).
• Any condition preventing adequate visualization and examination of pupil or optic nerve (e.g. dense corneal opacities or lens opacities).
• Active infection of anterior or posterior segments of the eye.
• Any intraocular surgical or laser procedure within previous 4 weeks.
• Any non-glaucomatous condition causing RAPD, anisocoria or corectopia (ex. optic neuropathy, Horner's syndrome, previous iris injury due to trauma or surgery, etc.).
• Subjects under age 18 or subjects presently housed in correctional facility.