Skip to main content
Menu

logo

glasses_wall_display
Home »

All About Vision

Low Vision

Low vision is significant vision impairment that usually results from serious eye disease or an injury. The vision loss, which is characterized by either reduced visual acuity (to 20/70 or worse) or reduced field of view, can’t be fully corrected with glasses, contact lenses, medication or surgery.

Low vision can affect both children and adults, but is more common in the elderly, who are at greater risk of eye diseases such as glaucoma, macular degeneration and cataracts, which are some of the most common causes of the condition.

Patients with low vision may have complete central or peripheral vision loss, blurry vision, poor low-light vision, loss of light sensitivity and/or loss of contrast, making daily activities such as writing, watching TV, driving or reading difficult or impossible. Since the vision loss can’t be corrected, low vision requires significant adjustments to daily life and the help of techniques and specialized low vision aids to help you maximize your remaining vision to increase independence and quality of life.

What are causes of low vision?

  • Eye diseases such as: glaucoma, macular degeneration, cataracts, diabetic retinopathy, and retinitis pigmentosa
  • Eye injury or brain injury
  • Heredity

How does low vision affect eyesight?

Low vision is partial vision loss which varies from person to person. Depending on the severity and type of vision impairment, the patient may have some useful vision. Typically the impairment includes a significant reduction in visual acuity to worse than 20/70, hazy, blurred vision, blind spots or significant visual field loss and tunnel vision. Sometimes the extent of vision loss is considered to be legal blindness (20/200 or less visual acuity in the better eye) or almost total blindness.

How does low vision affect daily life?

With significant vision loss it can become challenging to complete common daily tasks including reading, writing, cooking and housework, watching television, driving or even recognizing people.

When low vision is diagnosed it can come as a shock. Initially, it is an adjustment to learn how to function with impaired vision but the good news is there are numerous resources and products available to assist. Because low vision often results in one’s inability to work, function independently, drive and resume normal life, many patients feel isolated and depressed.

Visual Rehabilitation and Visual Aids

Low vision means that a minimal amount of sight remains intact. There are millions of people who suffer from the condition and manage to function with the remaining vision available to them through the use of visual rehabilitation or visual aids.

What are visual aids?

These are devices that help people with low vision function by maximizing remaining eyesight. This often involves the use of magnifiers (handheld, mounted or stand-alone), telescopes and other tools to enlarge the images of objects to make them more visible. Some visual aids reduce glare and enhance contrast which makes it easier to see. Other low vision aids act as guides to help the person focus on non-visual cues, such as sound or feel. Finding the right visual aid is a matter of consulting with a professional and experimenting with what works for you and your daily needs.

How to make life with low vision easier

  1. Ensure that you have adequate lighting in your home. This may require some trial

and error with different lights and voltages to determine what works best for you.

  1. Use a magnifier. There is a vast selection of magnifiers available, ranging from hand-held to stand magnifiers. Binoculars and spectacle mounted magnifiers are also an option.
  1. Your optometrist or low vision specialist can recommend specialized lens tints for certain conditions such as retinitis pigmentosa or cataracts, which enhance vision or reduce light sensitivity.
  1. Use large print books for reading. Alternatively, try digital recordings or mp3s.
  1. Make use of high contrast for writing. Try writing in large letters with a broad black pen on a white piece of paper or board.
  1. Adding a high-contrast stripe on steps (bright color on dark staircase, or black stripe on light stairs) can prevent falls in people with low vision, and may enable them to remain independent in their home.
  1. Find out what other technology is available to help make your life simpler.

If you or a loved one has low vision, don’t despair. Be sure to consult with your eye doctor about the best course of action to take to simplify life with low vision.

Did you know? There’s More To Child Learning Than Just 20/20 Vision!

There’s More To Child Learning Than Just 20/20 Vision

Even if you child has “20/20” eyesight he may be experiencing vision problems. These problems may be causing learning problems and substandard educational results. A child’s visual acuity ( how well s/he can see the wall chart) is an essential aspect of good vision but there are other factors which may prove more important. You may already be aware that a nearsighted child has little trouble reading or that good grades in school can be acquired even if much of the teacher’s board cannot be seen by the student.

Questions Related to Eyesight and Learning

Eye movement skills: Do your child’s eyes move across the page in a book smoothly and accurately?

Eye focusing abilities: Does your child change focus from near to far and back again -between reading text from a far-away white or black-board and writing on paper?

Eye teaming skills: Are your child’s eyes working together as a focus unit -do they come together for proper eye alignment for reading?

Binocular vision skills: Are your child’s eyes blending visual images from both eyes into a single, three-dimensional image?

Visual perceptual skills: Does your child identify and understand what s/he sees, co-relating importance, connecting with previous visual memorized information?

Visual-motor integration: Is the quality of your child’s eye-hand coordination balanced? Visual-motor integration is important not only for legible handwriting and the ability to efficiently copy written information from a book or board but also for sports. Deficiencies in any of these can be detrimental to a child’s learning ability and / or school performance.

Vision Problems Do Affect Kids Learning

Undetected learning-related vision problems in children are common. A child with an untreated vision problem may be misdiagnosed with behavior problems or ADHD/ADD when in reality they have a vision problem. Vision problems, in extreme cases, ignored or misdiagnosed, can become the true root cause of a child becoming the victim or aggressor in a school bullying tragedy.

Left untreated, vision problems will hinder your child’s learning in school. Studies have shown that at least 13% of children between the ages of nine-thirteen suffer from moderate to severe convergence insufficiency, the ability to bring one’s eyes together, which is crucial for good reading. Studies demonstrate clearly that one out of four school-age children suffer from at least one learning related vision problem.

Learning-Related Vision Problems

Signs and Symptoms

Some of the most common roadmap symptoms of learning-related vision disorders are:

  • Double vision, particularly during or after reading
  • Poor handwriting
  • Hyperactivity or recklessness during class
  • Word and letter reversals
  • Easily distracted during reading
  • Poor reading comprehension
  • Poor overall school performance
  • Circumventing of reading
  • Blurred vision, especially after reading or working closely
  • Eye Strain or frequent headaches

Call us to schedule a comprehensive child’s vision exam if your child exhibits one or more of these signs or symptoms and is exhibiting these types of problems in school.

Comprehensive Child Vision Exam

A comprehensive child’s vision exam includes tests performed in a routine eye exam, plus specific additional tests for detecting learning-related vision problems.

Extra tests would include accommodation, binocular vision, and ocular motility testing. In addition to these, depending on the type of problems your child is having, we may recommend other testing, either in our office or with a child’s vision and/or vision development specialist.

Vision Therapy

Special reading glasses or vision therapy may help your child if s/he has a learning-related vision problem that cannot be corrected with regular glasses or contact lenses. Vision therapy entails eye exercises and other activities especially tailored for each patient to improve vision skills.

Learning Disabilities and Vision

Although children with learning disabilities may also have vision problems that are contributing to their difficulties in the classroom, vision therapy is a treatment for vision problems; it does not correct a learning disability. A child’s learning ability and school performance may indicate learning disabilities and/or vision problems.

Once your child’s comprehensive vision exam is completed, your Grand Prairie TX eye doctor will advise you about whether a program of vision therapy could be helpful. We will refer you to a children’s vision or education/learning specialist if we do not provide the specified additional services your child needs.

Why are Eye Exams Important?

For both adults and children alike, eye exams are an important part of one’s general health maintenance and assessment. Your eyes should be checked regularly to ensure that you are able to see as best as possible. Regular eye health exams will also check for signs of eye disease or conditions that can affect not only your vision but your overall health. Vision and eye health is such a critical part in learning and development, therefore, we highly recommend eye exams for infants and children.

Vision Screening vs. an Eye Exam

When we recommend regular eye exams, this should not be confused with a vision screening. A vision screening is a basic test that indicates if you have difficulty seeing and require further assessment and corrective measures. It can be performed by anyone, whether it is a school nurse, a pediatrician or even a volunteer at a vision clinic. A vision screening usually only checks vision, it does not check eye health. Also, most vision screenings for kids only check for nearsightedness (when you can not see far), but what happens when the majority of children are farsighted? Most of the time many of these kids get overlooked.

A comprehensive eye exam on the other hand, can only be performed by an eye doctor as it requires special knowledge and equipment to look around and into your eye to check your eye and vision health. Such an exam can assess whether there are underlying causes for vision problems and whether there are any signs of disease which can threaten your site and the health of your eye. A comprehensive eye examination can also diagnose symptoms of diabetes, high blood pressure, high cholesterol, tumors, cancer, autoimmune disorders, and thyroid disorders. A comprehensive eye examination will also provide an accurate prescription for eyeglasses or contact lenses.

Eye Exams for Eye Health

Eye exams are critical because many vision threatening eye diseases such as glaucoma, macular degeneration, cataracts, or diabetic retinopathy have no or minimal symptoms until the disease has progressed. In these cases, early detection and treatment is essential to halting or slowing down the progression of the disease and saving eyesight. During a comprehensive eye examination, your eye doctor will be looking for initial signs of these diseases. If a problem with your eyes arises such as red eyes, eye allergies, dry eyes, eye swelling,eye pain, always seek an eye doctor as your first doctor to call since they are specifically trained to treat eye diseases.

Eye Exams and Children

If your child is having developmental delays or trouble in school there could be an underlying vision problem. Proper learning, motor development, reading, and many other skills are dependent upon not only good vision, but your eyes functioning together. Children that have problems with focusing or hand-eye coordination will often experience frustration and may exhibit behavioral problems as well. Often they don’t know that the vision they are experiencing is abnormal so they aren’t able to express that they need help. Many conditions are much easier to treat when they are caught early while the eyes are still developing, so it is important to diagnose any eye health and vision issues as early as possible.

Eye Exams Over 40

Just like the rest of our bodies, our eyes begin to weaken as we age. There are a number of common age-related eye conditions such as presbyopia, cataracts, and age-related macular degeneration that can begin to affect your vision and your daily life. While some of these conditions are more of an inconvenience, others could lead to vision loss and dependency.

In addition to regular yearly eye exams, it is important to be aware of any changes in your eye health and vision. Also know your potential risk factors as well as your family ocular and medical history. Over half of the vision loss worldwide is preventable with proper treatment and care.

Find out about Preparing for an Eye Exam

Preparing for an Eye Exam

For both adults and children, an eye exam is a critical part in maintaining your overall health and well-being, and therefore, regular eye exams should be incorporated into your health routine. Comprehensive eye exams assess your vision and the health of your eye, looking for early signs of disease that may not have obvious symptoms. You should not wait until you experience a vision problem or symptoms of an eye condition to schedule a routine exam.

Depending on your age, family history, general health and eye health, it is recommended to have an eye exam every one to two years. Of course if you experience any serious symptoms that affect your eyes or your vision, you should contact your eye doctor immediately.

The Difference Between an Optometrist (OD) and an Ophthalmologist (MD or DO)

Confusion about the difference between optometrists and ophthalmologists is common, and many people are not aware of how the two eye care professionals differ.

Optometrists

Optometrists or Doctors of Optometry attend optometry school which is usually at least four years of graduate level training. They are able to perform eye exams, provide prescriptions for eyeglasses and contact lenses, and diagnose and treat eye diseases as as glaucoma, dry eyes, or eye infections that may require medication or drops. They can consult with and co-manage patients in pre- or post-op surgical care, however they do not perform surgery.

Ophthalmologists

Ophthalmologists are medical doctors that attend medical school and later specialize in ophthalmology. They are able to do all of the services mentioned above but also perform eye surgeries such as cataract surgery, refractive surgery such as LASIK and deal with more urgent eye conditions such as retinal detachment.

Infant and Child Eye Exams

According to the American Optometric Association (AOA) children should have their eyes examined by an eye doctor at 6 months, 3 years, at the start of school and then at least every 2 years following. If there are any signs that there may be a vision problem or if the child has certain risk factors (such as developmental delays, premature birth, crossed eyes, family history or previous injuries) more frequent exams are recommended. A child that wears eyeglasses or contact lenses should have his or her eyes examined yearly.

Adult Eye Exams

Healthy adults under 40 with good vision and who do not wear eyeglasses or contact lenses are recommended to have an eye exam at least every two years. Those that do use vision correction or have a health issue such as diabetes, high blood pressure or another health condition that can have an impact on your eye health should schedule a yearly exam, unless the eye doctor recommends more frequent visits.

Once you reach 40, you become susceptible to a number of age-related eye conditions such as presbyopia, cataracts or macular degeneration, therefore annual or bi-annual exams are strongly recommended.

As you continue to age, particularly after age 55, the risks of eye disease increase, and early detection can be critical to preventing significant vision loss or blindness. Scheduling a yearly eye exam can make all the difference in maintaining your independence and quality of life.

How to Prepare for Your Exam

Prior to your exam you should decide whether you will be seeking special services such as a contact lens exam or LASIK consultation. These services may cost extra. Check with the doctor’s office or your insurance provider to see if they cover any of the exam expenses.

You need to know if you have medical insurance, vision plan coverage or both. Medical insurance usually does not cover “wellness/refractive” exams for glasses or contact lenses. Vision plans will cover exams for glasses or contacts, but usually cannot be used for red eyes, floaters, or other medical eye health problems. Please bring your insurance cards with you.

In addition to bringing your current pair of glasses or contacts if applicable, it is important to be aware of your personal and family history and to have a list of medications or supplements you are currently taking. Your pupils will probably be dilated as apart of your exam, so plan accordingly.

What to Expect at your eye exam?

Your Comprehensive Eye Exam

Your eyes are one of the most complex organs in your body. A comprehensive eye exam to assess your visual system and eye health involves a number of different of tests. Unlike a simple vision screening, which only assesses your vision, a comprehensive eye exam includes a battery of tests in order to do a complete evaluation of the health of your eyes and your vision.

The tests that you will undergo in a comprehensive eye examination may vary from eye doctor to eye doctor but here are are some common exams that you may encounter:

Patient Background and History

One of the most important parts in a comprehensive eye exam is your patient health history. This information will alert your doctor to any conditions that should be monitored closely, such as an allergy to any medications, current or family history of systemic or eye pathology or environmental conditions that could be affecting your vision or eye health. This will also help your doctor to determine any preventative eye care measures that are relevant to keep your eyes healthy for years to come.

Visual Acuity

Visual acuity is a measurement of your vision using an eye chart, the Snellen Eye Chart. In this test the patient is seated at a standard distance and is asked to read letters or symbols of various sizes, which get smaller as you move down the chart. The results are the familiar ratio of 20/20, 20/40 etc. which is a comparison of your vision compared to the average person with good vision, which is typically 20/20. For example, a patient that has 20/40 vision, can only see at 20 feet what the normal person can see from a distance of 40 feet. This test is a preliminary test of how clearly you are seeing in each eye but it does not give you a prescription for corrective lenses.

Refraction

Those who don’t have 20/20 vision have what is referred to in most cases as a “Refractive Error.” The patient may have nearsightedness, farsightedness, astigmatism or other eye conditions that prevent the patient from seeing 20/20. A refraction will tell the doctor which prescription lenses will correct your eyesight to achieve 20/20 vision or whichever amount your vision is correctable to.

A refraction may include a couple of steps.

Retinoscopy

Retinoscopy is a test that allows the doctor to obtain an approximate prescription for eyeglasses. In this test the doctor uses a hand-held instrument called a retinoscope that shines a light into the patient’s eye. The doctor then analyzes the reflex of the light from the patient’s eye to determine the patient’s prescription for glasses.

An instrument called a phoropter is something most patients associate with an eye exam. This space age appearing instrument, positioned in front of the patient’s face during the eye exam, gives the doctor the ability to determine the patient’s focusing ability as well as their eye alignment. The phoropter also determines which, out of the hundreds and hundreds of potential eyeglass prescriptions, will help the patient see as clear as possible. Using the phoropter, the doctor will ask the patient which series of lenses makes their vision the clearest.

While retinoscopy is quite effective for children and nonverbal patients, there are now a number of computerized or automated instruments available today to help doctors accurately determine a patient’s eyeglass prescription.

Autorefractors and Aberrometers

Autorefractors and aberrometers are computerized machines that are able to measure your refractive error to determine your prescription for glasses or contact lenses. These instruments are usually used in addition to testing described earlier:

- An autorefractor is similar to retinoscopy, which electronically analyses the light reflex from the patient’s eye.

- An aberrometer measures distortions or aberrations in the cornea and lens of the eye that disrupt proper focus of light on the retina. Using wavefront technology, the instrument measures the rays of light as they pass through your eye to look for imperfections which may indicate a refractive error.

Eye Focusing and Eye Teaming Tests

During the comprehensive eye exam, your eye doctor will also want to test how your eyes function individually and together from a mechanical perspective. In order to see clearly and comfortably, your eyes need to work together as a team.

Eye Health

The final and most important aspect of a comprehensive eye exam is a check of your overall eye health. These tests (below) are done to identify any eye conditions or diseases, both inside the eye as well as the external parts of the eye, that could affect your vision and general health.

Slit Lamp Test

The slit lamp or biomicroscope is an instrument that allows the doctor to examine the internal and external parts of the eye in detail, such as the conjunctiva, iris, lens, cornea, retina and the optic nerve. The patient rests their forehead and chin on a headrest to stabilize the head, while the doctor looks into the eye with the slit lamp microscope, which is magnified with a high-intensity light. A slit lamp test enables the doctor to evaluate the eyes for signs of normal aging and eye pathology, such as conjunctivitis, cataracts, macular degeneration or retinal detachment. Early diagnosis and treatment of eye diseases are essential for preventing vision loss.

Tonometry

Tonometry is a test to detect glaucoma by measuring the pressure inside your eye or IOP (intraocular pressure). Glaucoma can cause vision loss and even blindness if the IOP in the eye is too high and damages the optic nerve.

The applanation tonometer, typically attached to a slit lamp, is one of the most common instruments used to measure the pressure in the eye. Prior to doing this test the doctor will numb the patient’s eyes using an anesthetic, before gently applanating (putting pressure on) the patient’s cornea to measure the pressure in the eye.

Pupil Dilation

During your comprehensive eye exam, your doctor may decide to do a dilated eye exam. In this test, your doctor will instill dilating drops in each eye, which would enlarge your pupils to give the doctor a better view of certain parts of the back of the eye. Dilation is done at the discretion of the doctor, with some patients dilated every year and others at specified intervals; the frequency of dilation will vary for each patient.

Typically the drops take around 20 to 30 minutes to take effect and may last up to several hours following the exam; each patient is different. Since more light enters your eyes when your pupils are dilated, you will be more sensitive to bright light, especially sunlight. Although your doctor may provide disposable sunglasses, you may want to bring a pair of sunglasses to wear after the exam to make it more comfortable until the drops wear off.

A comprehensive eye exam is an important part of your overall general health maintenance and should be scheduled on a regular basis. The findings from your comprehensive eye exam can give your doctor important information about your overall health, particularly diabetes and high blood pressure.

Remember to book regular Pediatric Eye Exams for your children too!