SPECIAL TESTING
MS Eye CARE
Neuro-Ophthalmology of Texas, PLLC
Special testing may include any or all of the following:
Explanation of Testing for MS Suspects with Visual Problems
Dr. Rosa A. Tang, MD, MPH, MBA
Automated Visual Fields (CPT 92083) Click for pictures!
This is a mapping of both the central and peripheral vision for each eye. This test is subjective and quantifies a patient’s complaints of a visual field defect that can be IN THE CENTER OR THE SIDE VISION [peripheral]. Serial visual field testing is helpful in determining improvement or progression of visual field loss as well as consistency of responses.
Sensory Motor Exam /Stereo Testing (CPT 92060) Video Coming Soon!
This
consists of an objective portion: Sensory motor test which detects abnormalities in eye movements that tend to correlate with the patient’s visual complaints of double vision or jumping vision [nystagmus]. The subjective part of the test is Stereo testing which allow us to determine 3D vision capabilities.
Orthoptics Evaluation [ Click Here to meet our Orthoptist ]
Orthoptics is an ophthalmic field pertaining to the evaluation and treatment of patients with disorders of the visual system with an emphasis on double vision, binocular vision and eye movements. Orthoptists are uniquely skilled in diagnostic and treatment techniques. Orthoptics is a versatile field with opportunities and responsibilities in a variety of clinical settings. Orthoptists may serve their communities in private ophthalmology practices. Others may work in hospital or medical university settings with involvement in patient care, academics and clinical research. Orthoptists may serve as directors or advisors of state and local vision screening programs. Orthoptists serve patients of all ages, but because of the nature of many binocular disorders, the majority of patients are children. Adult care in the field of Orthoptics is uniquely challenging and rewarding, found in settings of neurology specific to neuro-ophthalmology and adult eye muscle disorders.
Pattern Visual Evoked Response [VER/VEP]
Multifocal VEP [MFVEP] (CPT 95930) Click for pictures!
This is an objective test that gives us a recording of the electrical activity of the visual pathway. The patient has electrodes placed in the head and is asked to look at a TV type of display with a checkerboard or a flash light. A recording is generated by this display /flash that appears as a wave. Measuring the wave characteristics we can infer what part of the visual pathway may be causing the loss of visual field. The multifocal VEP creates about 60 potentials mapping smaller areas of the nerve and giving a more detailed finding of a problem with conduction of nerve impulses. In Multiple Ssclerosis patients characteristically show a DELAYED impulse response on the VEP and the MFVEP due to the myelin being affected [myelin is the insulator of the nerve].
Multifocal Electroretinogram [MFERG] Click for pictures!
The multifocal ERG (mfERG) is a test to determine local retinal function by recording from the corneal surface of the eye. The test is similar to the more commonly recorded full field ERG that tests the function of the whole retina. The mfERG is recorded with dilated pupils, and thin fiber electrodes called DTL electrodes are lightly placed underneath the lower lid (both eyes) of the patient. The patient is asked to look at the center of a display consisting of an array of black and white hexagons on a video monitor. The number of hexagons can vary from 37 to 241; an array of 103 hexagons is most commonly used. The hexagon sizes are scaled to obtain responses from same number of retinal photoreceptors (the cone photoreceptors) and to produce equal ERG responses at all locations. During recording, the display alternates between black and white in a predetermined sequence for each hexagon. One complete recording from each eye takes about 8 minutes and for the comfort of the patient the recording is broken into 15 second segments to allow the patient to blink. At the end of the recording, ERG responses are calculated by the recording system for all hexagon locations. By comparing the responses from each retinal location with those from age-matched normal eyes, it can be determined if there are any retinal areas with abnormal function.
The Electroretinogram (ERG) (CPT 95930) Click for pictures!
This is an objective test somewhat similar to the VEP but test RETINA function not OPTIC NERVE function. A contact lens is placed in each eye and the response to a flash of light is recorded as the electrical activity of the retina (recorded by electrodes placed in the face/head). This is a test not use in patients known to have MS but in patients whose visual loss’ cause is not known to see if the visual loss is of retinal origin.
Optic Nerve/Retinal Topography Click for pictures!
This
uses a scanning laser to measure nerve fiber layer thickness, as a way to gauge nerve fiber function, particularly in diseases affecting the optic nerve. Decrease in the thickness of the nerve fiber layer is found in patients with MS and can be used to determine progression over time of the disease contributing to loss of nerve fibers. The instruments are called OCT, GDX, HRT among others.
Fundus photography (CPT 92250) Click for pictures!
Fundus photography is an objective way to document the appearance (color, shape, distribution, etc.) of the optic nerve and retina and any abnormal intraocular lesions that are the explanation of central or peripheral visual loss in one eye.
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