Low Vision Awareness Month – What Is a Low Vision Exam Anyway?

Dr. John Metzger is one of Kansas City’s leading optometrists with more than 40 years of experience. Dr. Metzger works in the special areas of developmental optometry, vision therapy, low vision rehabilitation and neuro-optometry. He assists people of all ages whose vision restricts reading, learning, work tasks, hobbies, driving and enjoying daily life.

We asked Dr. Metzger if he could shed light on what’s involved with a Low Vision Exam and how it differs from a traditional eye exam.

Just What Is a Low Vision Exam?

A brief Google search estimates the Kansas City metropolitan area alone has approximately 350,000 individuals with visual impairment. Despite that figure, there are likely only about a dozen eye doctors providing low vision care in the area. Frankly, that’s not nearly enough. At KC Vision Performance and the Alphapointe Low Vision Clinic, some patients travel 80 miles for services. The bottom line is that a lot of people are not getting care.

Given that the National Eye Institute has slated February as Low Vision Awareness Month, let’s examine what is different about a low vision exam that makes low vision doctors so rare. You can be certain that there are many eye doctors who do elementary low vision care in their general practice. I did when I practiced in a rural town. I think the chief reason why full scope low vision care is rare is that it takes a longer time to provide the service.

What’s involved in a low vision exam?

Here is a list of routine items to evaluate needs and solutions for patients with impaired vision:

• A trial frame exam: Those of us who wear glasses or contact lenses peer through a phoropter at the eye doctor’s office while they flip the dials, asking, “which is better, number one or number two.” During the low vision exam we often use a “trial frame” rather than the phoropter. The trial frame looks like a set of “steam punk” eyeglass frames with slots for lenses and dials to rotate the lenses. The first advantage is that we can give larger jumps of focus during the “one or two” part of the test for patients who cannot tell the difference between small changes of a phoropter test. This makes it easier for the patient to make choices. The second advantage of the trial frame is that the patient can use more of their side vision during the test, which can be helpful in finding the “sweet spot” on the nerve tissue inside the eye where vision is best.

 

• Eccentric fixation: Speaking of the “sweet spot,” frequently an eye disease will erode or scar the “bull’s eye’ inside the eye where the image has always fallen. Then the patient must look off center to get the image on good nerve tissue. This is not necessarily a problem if a patient has one fairly good eye and one eye with a damaged bull’s eye area but when both eyes lose the critical bull’s eye we have to teach the patient to habitually and accurately look off center to get the best image possible. In other words, the patient may have to look toward a friend’s ear to see the friend’s eyes and mouth.

 

• Different charts:  In the range of poor vision in which many low vision patients operate, a standard eye chart does not have small enough letter sizes to test critically and find the very best lens for sight. Low vision charts may have eight size differences in a given range, while a standard office chart has only four sizes in the same size range.

 

• Demonstrate, demonstrate, demonstrate: It probably comes from my early career as a science teacher, but I like to do demonstrations. I want the patient to see as exactly possible how new lenses will make things look: driving, reading, computer, hobbies. For example, if we use magnifying glasses for printed material, they should know just how much closer the new lenses will cause them to hold the newspaper. When I practiced in that country town, the town’s folk would think I was on a lengthy vacation if they didn’t see me, a patient and a trial frame out on the sidewalk in front of the office pretty frequently. New lenses may work fine in the exam room, but do they really help outside?

 

• One size fits all: Usually a set of glasses with different distance and near prescriptions work fine. Many of us wear no-line or lined bifocals, which are two glasses in one. But with low vision, the best vision cannot be attained with standard lenses. It depends on the task and the vision problem at hand. After demonstrations, I may suggest two or even more sets of eyeglasses to solve visual problems. A patient might say, “Whoa doc, you mean I have to switch back and forth?” To which I would say, “Well…how many different screw drivers to you have in your toolbox?”

 

• Tint selection: One part of a low vision exam which is often helpful, but requires additional time is tint selection. We find that diseases which cause vision loss can make things hazy and indistinct. Sometimes rather funky colors can improve contrast and not only improve general vision, but also safety as steps and curbs are easier to judge.

 

• A team!: My low vision job is to get the ball rolling by making sure eyes are in focus and assessing basic visual status. Then, I often turn my patient over to another member of the team, an occupational therapist. These folks are problem solvers of the highest order and get down into the real practical activities concerning home and job life. Many times they will visit the home or job site to further assess needs and to ensure that recommendations are doing the job. They work with a variety of devices which may read text to you or tell you what color your garment is. They determine if electronic devices can magnify better than standard magnifiers. They analyze safety and lighting factors. They can teach computer skills for visual impairment. They get the home organized for greater independence: kitchen tasks, appliance use, how to take care of finances and sign checks easier, etc. Additional team members teach mobility, so you can get around easier at home and be more confident in public. Our technology instructor teaches high level computer skills and many of his students go on to job opportunities.

So, these are a few reasons why a full scope low vision evaluation takes longer and is somewhat rare. We encourage patients to come with a goal and tell us what’s bugging you. Although we can’t put back what is gone from disease, we can show you how to use your vision to the best advantage.