What Is a Low Vision Examination?
If an individual has one or more eye disorders, such as glaucoma, cataracts, macular degeneration, or diabetic retinopathy, it's important to have a low vision examination—performed by an ophthalmologist or optometrist who specializes in low vision—to determine whether special low vision optical devices, better lighting, or other types of training can help the person with low vision to use his or her functional vision more effectively.
Some examples of functional vision problems can include:
- Difficulty seeing the height of the gas flame when cooking
- Problems crossing streets or seeing traffic
- Difficulty seeing information on a computer screen
- Problems threading a needle or making clothing repairs
- Difficulty using the telephone book or reading magazines, even with regular eyeglasses.
The low vision specialist is trained to conduct a functional eye examination that focuses directly on how a particular person's vision impairment affects day-to-day living.
A low vision specialist can prescribe low vision optical devices, such as magnifiers, magnifying reading glasses, and telescopes, and recommend non-optical devices and solutions, such as improved lighting, closed circuit televisions and video magnifiers, large print reading materials, and a wide range of adaptive daily living devices and training.
Preparing for the Low Vision Examination
Before arriving for the low vision examination, it's helpful to make a list of questions for the doctor. Here are some suggestions:
- What is the name of my eye disease or disorder?
- What is the cause of my vision loss?
- Is my condition stable, or can I lose more sight?
- Is there any treatment for it?
- What is my visual acuity?
- Do I have a loss of side (or peripheral) vision?
- Will regular eyeglasses help me?
- How can I protect my remaining vision?
- Do I need any special medications?
- Do I qualify as "legally blind?" If so, what does "legally blind" actually mean?
- Am I entitled to any special services or benefits?
- What resources and rehabilitation services are available to help me?
Also, it is helpful to make a list of activities that you want and need to do, such as sewing, playing cards, watching ball games, or going to the theater, and to list the types of reading materials you want and need to access. This information can help focus your discussions with your low vision doctor and his or her professional staff.
The Low Vision Examination
The low vision examination should include the following components:
A Health and Medication History
- Your overall heath and that of your immediate family
- The medications you are taking (prescription and over-the-counter)
- Questions about high blood pressure (hypertension), diabetes, smoking, and sun exposure.
A Vision History
- How well you can see at present, including any recent changes in your vision
- Eye diseases that you or your family members have had, including macular degeneration and glaucoma
- Previous eye treatments, surgeries, or injuries
- The date of your last eye examination
A Low Vision History
- When your vision problems began
- Any prior vision rehabilitation services you've had
- Questions about activities that are becoming difficult for you, such as reading, meal preparation, and/or walking indoors and outdoors.
An Eye Health Evaluation
- An examination of the external parts of your eyes
- A dilated internal examination. Special eye drops will dilate, or open, your pupil, which allows the doctor to observe the inner parts of your eye, such as the retina and optic nerve.
- A test of the fluid pressure within your eyes.
A Low Vision Refraction, or Visual Acuity Testing
In a low vision examination, your doctor will use special low vision eye charts that are different from the eye charts used in a regular eye examination. These special low vision eye charts contain different sized large letters and numbers that can help determine the sharpness or clarity of both your near (reading) and distance vision.
Bailey Lovie Acuity Chart
Feinbloom Distance Chart
The doctor may also use the Amsler Grid test to check for the presence of age-related macular degeneration (AMD) or other eye disorders, such as diabetic retinopathy. Wavy, distorted, missing or broken lines, or holes or black spots in the grid can indicate problems that require monitoring.
Amsler Grid Test
Amsler Grid Test Distorted
Visual Field Testing
- To determine how much side (or peripheral) vision you have and how much surrounding area you can see
- The low vision specialist will likely perform a very precise visual field measurement, using a computerized visual field analyzer, such as the Humphrey, or a non-computerized visual field test, such as the tangent screen or
the Goldmann field exam.
Humphrey field analyzer
Goldmann field exam
And a variety of specialized tests to measure:
- Depth perception
- Color vision
- Contrast sensitivity
Since much of the examination will focus on what your functional needs are in your day-to-day life, you will be asked a wide range of easy-to-answer questions. Some of these questions will be about your habits or activities in reading and near vision activities, such as the following:
- What size print can you now read?
- Do you want to continue reading newspapers?
- Can you read your bills?
- Do you want to read the TV Guide?
- Do you "spot" read more than you read novels or other books?
- Have you had low vision devices, such as magnifiers, in the past? If so, do you still use them? If not, why not?
In terms of everyday activities, questions may include:
- Can you see to use a checkbook?
- Can you read your watch?
- Can you do regular household tasks, such as cleaning and laundry?
- Can you care for your personal grooming needs, such as shaving or applying makeup?
- Can you see to use the computer?
- Are you able to continue your hobbies?
- Can you watch television?
- Can you travel independently and safely?
- What difficulties are having when traveling in your community?
- Are you still driving? If so, do you still feel safe driving?
- Does bright sunlight bother you?
- Has your vision problem affected your employment or educational studies?
- If you're a diabetic, can you see to fill your insulin syringes?
- Can you differentiate between your medications?
All of these questions are designed to gather information about your day-to-day functional needs and explore possible options for addressing those needs. A typical low vision examination is not rushed and is very thorough; for this reason, it can take 2-3 times longer than a regular eye examination.
The doctor and his or her staff may also introduce, and measure your response to, different lighting conditions and different colored sunlenses and filters that can control glare.
A key part of the examination is for you, your doctor, and his or her social worker to discuss how you are adapting emotionally to your vision loss, whether you are motivated to learn a different way of doing things, and if you have family and friends to support you.
Vision Rehabilitation Services
Certified Low Vision Therapists (CLVTs), Vision Rehabilitation Therapists (CVRTs), and Orientation and Mobility Specialists (COMS) often work in close partnership with the optometrist or ophthalmologist and provide training in how to use low vision optical or non-optical devices in practical everyday situations.