Guidelines for Predicting Performance with Low Vision Aids

Authors

Latham, Keziah; Tabrett, Daryl R.

Guidelines for Predicting Performance with Low Vision Aids

publication date

March 1, 2012

Abstract/Introduction

Purpose.

To determine predictors of success in reading with low vision aids, in terms of reading acuity, optimum acuity reserve, and maximum reading speed, for observers with vision loss from various causes.

Methods.

One hundred people with vision loss affecting their daily lives participated. Clinical visual function measurements of distance acuity, contrast sensitivity, binocular threshold visual fields, and near reading performance with a MNRead chart at 40 cm were obtained. Reading performance aided by habitual low vision aids was also assessed with a MNRead chart.

Conclusion/Results

Results.

Aided reading acuity was best predicted by clinical reading acuity and contrast sensitivity. For most observers, a 2:1 acuity reserve was sufficient to achieve near-maximum reading speed, but one-third of observers with aided reading acuity better than 1.2M required a higher acuity reserve. Aided maximum reading speed was best predicted by clinically assessed reading speed and by clinical reading acuity.

Conclusions.

People with vision impairment are likely to achieve 1M with a low vision aid if their clinically assessed reading acuity is better than 0.85 logMAR. If acuity is worse than this, but contrast sensitivity is better than 1.05 logCS, 1M is also likely to be achieved. A 2:1 acuity reserve is adequate for 75% of observers, but those with good aided reading acuity may require further magnification to achieve best reading speeds. Fluent reading (>80 words per minute) is likely to be achieved if an observer reads fluently with large print at a fixed working distance and if clinically assessed reading acuity is better than 1.0 logMAR.

Testimonials

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.

Anna P.

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.

June S.

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.

Christine R.

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.

Lars Wulff

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.