Special Testing
Laser Coherence Tomography (LCT). This diagnostic test uses a form of laser light to create a three dimensional image of the optic nerve. Early changes in optic nerve structure related to glaucoma can be found with this technology. This allows treatment to be started before significant nerve damage and loss of vision occur.
Foresee PHP: Macular degeneration (AMD) is the leading cause of blindness in patients over 50. In this disease, the very thin, sensitive tissue in the back of the eye that is responsible for one’s central vision, the macula, is progressively damaged. There are two forms of AMD: Dry AMD and Wet AMD. Macular degeneration begins as Dry AMD, which comprises 80-85% of all cases, and is less severe. It can progress to Wet AMD when tiny blood vessels beneath the retina grow out of control causing leakage of fluid and blood under the retina, resulting in a devastating loss of vision. Unfortunately, Dry AMD can progress to Wet AMD slowly, painlessly and initially without symptoms.
Early Wet AMD can be treated with medications and/or laser surgery, but this must be done within a very narrow window of time to be effective. Detecting wet AMD at its earliest stage comes down to timing, and timing is everything! If macular changes are detected early and treated immediately by a retinal specialist, vision can often be spared.
Determining if and when Dry AMD turns into Wet AMD can be difficult if one’s vision is not diligently monitored with a sensitive monitoring tool. Up until recently, doctors have recommended that patients with Dry AMD monitor each eye’s vision on a daily or weekly basis using a card with a grid of lines on it, called an Amsler Grid. This helps to detect distortions in one’s vision caused by blood vessel changes in the macula. The Amsler Grid is still a useful tool and it is important that one continue to view it as directed by your doctor. However, advances in technology have come up with even more sensitive ways of detecting changes in one’s central vision, revealing Wet AMD at its onset and early stages before damage causes permanent vision loss.
The Valley Vision Clinic has the latest technology in detecting symptoms of early Wet AMD: The Foresee PHP. It is a quick, FDA approved, non-invasive method of detecting changes in AMD. The Foresee PHP uses linearly placed dot patterns on a touch-sensitive screen to help identify macular changes. The test itself takes about 15 minutes and has a sensitivity level of 82%. Testing one’s central vision at regular intervals with the Foresee PHP has been shown to help detect and monitor the progress of AMD more effectively than Amsler Grid testing alone.
Digital Imaging: The phrase “A picture is worth a thousand words” holds true in the world of medical records as well. By taking digital photos of both the posterior (back) and anterior(front) segments of the eye, at Valley Vision Clinic we are able to monitor disease processes much more effectively by having digital, full color photos to document ocular conditions. By taking photos, we establish an objective document that will remove any doubt about any changes in your condition from year to year. (retina and ant seg photos)
VEP (Visual Evoked Potential): The Valley Vision Clinic is one of the few facilities in the upper mid-west capable of assessing visual function electrodiagnostically. The Visual Evoked Potential (VEP) is a brain-wave test taken while a patient views various visual stimuli on a flat monitor. It is a non-invasive medical device used to test for visual deficits in children six months of age and older. The test does not require dilation or sedation. A VEP is particularly valuable in assessing the acuity of an infant, pre-verbal or non-verbal child. This is often when amblyopia (lazy eye) is susptected. In addition, patients who have sustained a traumatic brain injury or have an acquired neurological disease can be assessed to determine if a visual pathway dysfunction exists. After positioning three sensory pads on the child or adult’s head, an operator initiates the test. The VEP recognizes the neurological responses and processes the VEP data, which is then analyzed by the optometrist.
IZON: No two eyes in the world are alike, not even your own two. Yet, until now the technology did not exist to customize glasses to your own ocular fingerprint or iPrint. New customized iZon lenses are High resolution lenses and the only lenses powered by your own iPrint. Because they are custom made for you, they address vision problems associated with some irregularities and aberrations of the eye that other lenses can’t. Your vision is optimized, you’ll see at peak performance. Your vision will be clearer, sharper, and more vivid than ever before. It;s been described as the difference between regular TV and HDTV.
The iPrint is gathered using a wavefront aberrometer, that traces light rays that enter and exit your individual eye. Nearly every patient at Valley Vision clinic has this test performed as part of there yearly eye exam at no additional cost to them.
Visual Field: Testing the visual field is important in the diagnosis and monitoring of many eye diseases including glaucoma. At Valley Vision Clinic, we use automated Humphrey visual field testing. Normal field testing is conducted by flashing white spots of varying brightness on a white field, the patient is instructed to click a mouse if they see the flash. A computer algorithm maps the field and produces a detailed printout of each eyes individual field. These results can be compared from year to year to determine any disease progression.
At our clinic, we have an advanced software system that uses a blue spot on a yellow background for testing the visual field. This technology called short-wavelength automated perimetry (SWAP) has been shown to indicate visual field changes much sooner in the glaucoma disease progress than traditional white on white testing.
Visagraph II Eye Movement Recording System: The Valley Vision Clinic uses an objective eye movement measurement system for recording and evaluating reading efficiency and effectiveness. Known as the Visagraph II, it is used as part of a comprehensive learning-related vision assessment and provides a detailed analysis of an individual’s oculomotor reading performance. Special goggles with infrared sensors record eye movement behavior while a patient reads text of various grade levels of difficulty. The Visagraph® II provides a comparison of measurements in relation to normative data to help determine the whether or not a visual problem may be hindering reading performance and efficiency. The Visagraph II® provides unique insight into the physical, perceptual, and cognitive skills involved in reading.
Coherent Motion Threshold Test: Research during the past 20 years has influenced the management of diagnosis and treatment of individuals identified as having learning-related vision problems and other neurologically-based vision problems. By using a computer generated random dot kinematogram, the presence and severity of possible impaired motion sensitivity can now be determined. This function is thought to be associated with the magnocellular visual pathway of the brain, a pathway that is involved in visual attention, reading fluency and comprehension. Once a patient’s coherent motion threshold is determined, therapy can be prescribed to improve magnocellular function and associated reading processes. The Valley Vision Clinic is one of the few facilities in the upper midwest that uses this technology as part of a comprehensive learning-related vision assessement.
Dyslexia Determination Testing: If an individual has trouble in reading and spelling, it is often valuable to determine whether or not these reading problems are specific (due to dyslexia), non-specific (due to problems in attention, vision, hearing, attitude, etc.) or a combination of both. To help determine the presence or absence of a specific reading disability, the Valley Vision Clinic has over 20 years of experience using the Dyslexia Determination Test (DDT) which is normed for grades 2 through 12. The DDT provides evaluation of eidetic (visual) decoding skills of sight-word recognition and phonetic (auditory) word attack skills as well as these categories for encoding (spelling) of words and, also, evaluation of motor skills in writing as regards letter reversals. This testing is part of a comprehensive evaluation for learning-related vision problems and allows for determination of whether dyslexia is present and, if so, the type and severity of it.
Ocular B-Scan Ultrasonography
B-scan ultrasonography is an important adjuvant for the clinical assessment of a variety of ocular and orbital diseases. Ophthalmic ultrasonography uses high-frequency sound waves, which are transmitted from a probe into the eye. As the sound waves strike intraocular structures, they are reflected back to the probe and converted into an electric signal. The signal is subsequently reconstructed as an image on a monitor, which can be used to make a dynamic evaluation of the eye or can be photographed to document pathology. Using B-Scan Ultrasonography, the doctors at Valley Vision Clinic can gather a vast amount of information not possible with clinical examination alone. B-scan ultrasound is most useful when direct visualization of intraocular structures is difficult or impossible. Situations that prevent normal examination include lid problems, corneal opacities (eg, scars, severe edema), hyphema, hypopyon, miosis, pupillary membranes, dense cataracts, or vitreous opacities (eg, hemorrhage, inflammatory debris). In such cases, diagnostic B-scan ultrasound can accurately image intraocular structures and give valuable information on the status of the lens, vitreous, retina, choroid, optic nerve and sclera.