Bloodshot eyes can be alarming, but they are not always a cause for concern. In this blog, we will discuss […]
Purpose.
Vergence facility testing attempts to assess the ability of the fusional vergence system to respond rapidly and accurately to changing vergence demands over time [defined as the number of cycles per minute (cpm) that a stimulus can be fused through, alternating base-in (Bl) and base-out (BO) prisms]. Decisions to use vergence facility as a clinical test are hampered by a lack of systematically gathered normative data.
Methods.
Twenty symptomatic and 20 control subjects with ages between 18 to 35 years of either sex and any race were pooled, based on vision-symptom level determined by a self-report questionnaire. Inclusion/exclusion criteria included vision correctable to 6/6 (20/20) Snellen acuity or better in each eye and normal phorias. Vergence facility response was tested over a 1-min period, using 16 combinations of BI/BO flip prisms at 4.0 and 0.4 m, based on Morgan's norms and pilot data.
Results.
Horizontal vergence facility responses were not the same among those with and without symptoms, and not all magnitudes of BI/BO flip prisms produced the same response difference. A single flip prism, 3 Δ BI/12 Δ BO, was found to differentiate optimally between groups at distance and near. Repeatability of test results (with the 3 Δ BI/12 Δ BO prism) was poor at distance and good at near.
Conclusions.
In addition to providing valuable normative data, this study indicates that the vergence system nearly resets its “zero point” at any distance and sheds further light on the results of dynamic convergence and divergence stimulation on the accommodative-vergence system. From a clinical standpoint, the results improve the diagnosis of binocular vision abnormalities. The recommended near vergence facility test is easily implemented, using a commonly available flip prism (3 Δ BI/12 Δ BO) and having a clinical failure criterion that is easily recalled (15 cpm, sum of the Bl and BO magnitudes).
Such a nice optician. My grandson is only 4 and needs glasses. We were so sad, but he explained the issues, and we will follow up as he suggested.
I had such a good experience with the clinic. Very friendly staff and doctor, did not have to wait for long to be called, and was treated respectfully. Thanks, American Family.
Dr. Zurcher has gone above and beyond what any other eye doctor has ever done to figure out what is going on with my eyes. Very happy with American Family Vision.
Family Vision Clinic changed our lives! My daughter was frequently car sick, and she was getting headaches every day, often painful enough that they brought her to tears. We saw a string of doctors and therapists, but we made no progress. Finally, we found Dr. Levi Zurcher and his eye therapist Rain. After ten weeks of eye therapy my daughter no longer gets headaches, and she no longer gets car sick. Daily tears are a thing of the past. I really can’t say enough about this clinic. It was fascinating to watch Dr. Zurcher work. For the first time, someone who knew what they were doing was intently studying my daughter, really trying to figure out all of her eye issues, and his therapist Rain is one of the most patient and lovely people that I’ve ever had the good fortune to meet. We’re finished with eye therapy—yay!—and I have switched to American Family Vision Clinic for all of my family’s other eye health needs.
Very professional, yet kind and helpful. They do what they can to make the appointment comfortable. I was running a bit late, I made sure ti call. They were able to switch me with a patient who was already there, they treated me with respect, and helped my son have confidence by getting him the eye care he needed that day. Thank you so much! Would recommend to anyone. It's a blessing that they care enough to work with people who have all different types of insurance from work to state coverage.
The staff is friendly. The Doc is very knowledgeable. The office is family friendly and everyone is so patient with the little ones.
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