Online Vision Test

This contains two printable vision tests and one test to be done on the computer monitor without printing. Please read this important information before proceeding further.

This section is not intended to replace the professional examination and diagnosis by a physician or eye care provider. They are presented here purely for informational purposes. The availability of these vision tests should not be taken as a recommendation to self-diagnose or self-treat a condition. A misdiagnosed or improperly treated eye condition can result in a permanent loss of vision, or a permanent loss of function of the eye or visual system. In the case of any eye problem, seek medical attention promptly. This can include emergency room treatment, as well as treatment by a medical physician or eye care provider.

The Amsler Grid is useful for monitoring the function of the macula, or the central area of vision. Certain disorders, such as macular degeneration, can lead to distortion of the retina due to hemorrhage or swelling. This leads to distortion of the visual image perceived by that area of the retina (much like camera film that is wrinkled in the camera will give a distorted photograph). In many cases, a person can monitor their vision with an Amsler Grid to check for distortion, blind spots, or changes in previously existing abnormalities. Some conditions that are monitored with an Amsler Grid include:

  • Age-related Macular Degeneration (ARMD)
  • Drusen (deposits) present in the macula
  • Ocular Histoplasmosis Syndrome (OHS or POHS)
  • High Myopia (nearsightedness) with retinal degeneration
  • Plaquenil (hydroxychloroquine) or Chloroquine use (a drug used for rheumatological conditions)
  • Central Serous Choroidopathy
  • Cystoid Macular Edema
  • Many others

Amsler Test

When printing, the following settings should be used in the printer setup, as available:

  • The page should be centered vertically and horizontally.
  • The size of the image should be kept the same, not enlarged to fill the page.
  • Print as portrait, not landscape.
  • The graphics type should be monochrome (black and white), and print resolution set to “high”.

The grid should be approximately 4 by 4 inches after printing.

To use the grid, place it in a visible location with good lighting, such as on the refrigerator. With one’s normal glasses correction for reading (reading glasses or bifocals if needed), view the grid, one eye at a time, at normal reading distance. Look at the central dot. As the dot is visualized, and without moving the eye, note whether or not there is any distortion or breaks in the lines of the grid. Also note if the dot, part of the dot, or if any of the lines disappear. Blurred or double images might not necessarily be abnormal. The use of progressive, lineless bifocals may introduce some distortion in the grid. After one eye is checked, check the other. The whole process may take only 10 seconds. Check the grid daily, or as often as recommended by the treating physician.
If a change is noted on the Amsler Grid, such as new distortion or blind spots, notify the treating ophthalmologist immediately (the same day).

This is a test of the distance visual acuity using the “E Game”. This test can be performed by adults as well as children. Below are instructions on how to print and administer the test. While this vision test is felt to be accurate, it does not substitute for vision tests given by a health care professional or eye care professional. Due to differences in monitor size and resolution, this test is not accurate when read from a computer monitor or television. Also, due to differences in printer resolution and setup, there can be variations in the appearance of the test. Included is a calibration bar that can be measured to determine that the letters are of the correct size.

Distance Vision Test

When printing, the following settings should be used in the printer setup, as available:

  • The page should be centered vertically and horizontally.
  • The size of the image should be kept the same, not enlarged to fill the page.
  • Print as portrait, not landscape.
  • The graphics type should be monochrome (black and white), and print resolution set to “high”.

Before the test is administered, check that the length of the calibration line is 100 millimeters (3 15/16 inches). If the distance is 100 mm, then the 10 foot testing distance is accurate. If it is different than 100 mm, the testing distance will have to be altered in order to give the proper visual acuity result. See below to adjust the test distance.

The test should be given in good light. The printed eye chart should be placed upright on a wall, and the testing distance should be measured exactly (10 feet, or as determined below). The person taking the test should stand at the testing distance. The person taking the test should cover one eye at a time. The lowest line that can be read correctly is the visual acuity for that eye. Note that since only the 20/20, 20/40, 20/100, and 20/200 lines are represented, a person’s visual acuity could fall between the levels represented. (For example, if the 20/40 line could be read, but not the 20/20 line, the vision is at least 20/40, but could also be 20/30 or 20/25.)

When testing children, make sure that the covered eye is truly covered. Since peeking through fingers is possible, it is more reliable to place an opaque object over the eye that is not being tested. For variation, the chart can be turned upside-down, or sideways.

Adjusting the Test Distance if the Calibration Line is not 100 millimeters:

The distance that one should stand in inches from the test chart can be calculated by multiplying the length of the calibration line in millimeters by 1.2:

Test Distance in Inches = Calibration Line Length in Millimeters X 1.2

Thus, if the calibration line is 100 mm, then the person taking the test should stand 100 mm X 1.2 = 120 inches, or 10 feet, from the chart.

Approximately 8% of males and less than 1% of females are born with an inherited type of color blindness, known as “red – green” color blindness. In this disorder, there may be confusion in distinguishing certain hues from one another. For example, certain reds, browns, olives and golds may be confused. However, pure red would be easily distinguished from pure green, in this particular type of color blindness. There are many varieties and degrees of color blindness, and this color vision test only pertains to the most common type, the inherited red – green type of color blindness. This test may not be accurate due to the wide variety in the ways colors are displayed on different monitors and with different internet browsers. Certainly, it would be doubtful that a printer would display the colors correctly, so it is not recommended to print the test to take it. An individual’s eye care provider can test color vision most accurately.

When taking this color vision test, look for a number in each figure. Observe the computer monitor at a normal distance and with glasses, if necessary. The eyes can be tested separately, or together. After taking the test, return to this page to see the answers displayed.

Missing a few of the numbers may be normal, but missing the majority of the numbers may indicate a color vision abnormality.



Symptoms & Disorders

Blurred vision can be refractive or pathology related. Usually, blurry vision is caused by one of the 4 most common eye problems.

  1. Nearsightedness or Myopia- the distance is blurred.
  2. Farsightedness or Hyperopia- the near requires more effort than the distance.
  3. Astigmatism- vision is distorted at both far and near.
  4. Presbyopia- the near is blurred.  Usually affects people over 40 years of age.

Other causes may be:

  1. Cataracts-a cloudiness or fogginess at both far and near caused by clouding of the lens in the eye.  In past generations, cataracts were common with people over70.  However, now younger people are developing cataracts. Possible causes are environmental or diet related.  In our practice it is not uncommon to refer patients for cataract surgery in their mid-50’s.
  2. Allergies-tearing and mucous discharge affect the tear film which is the first part of the human optical system.
  3. Changes in blood sugar-sudden onset of blurred vision over the course of a few days.
  4. Retinal Disease-more common in older people. Usually slow to develop unless related to a retinal hemorrhage which is sudden.

Any redness of the eye can be called conjunctivitis. Allergy, infection by a virus or bacteria, or mechanical irritation will cause redness. The term “Pink Eye” has commonalty come to mean an infection that is severe and communicable. All red eyes need to be evaluated by a doctor to determine the cause and treatment.
The most serious problem associated with Diabetes is hemorrhaging in the retina. This is most common in patients who have been a diabetic since childhood although Adult Onsets who are poorly controlled suffer from this also. Eye Doctors team with your family physician to monitor any changes in the eye so that corrective measures can be initiated as soon as possible. Maintaining your A1C below 7 is the best way to prevent retinal hemorrhages.
Dry Eye affects people of all ages. Causes are complex and can include inflammation of the tear producing glands, lid infection, and blocked oil glands in the lid leading to rapid evaporation of the background moisture of the eye or medication side effects. Evaluation is necessary to determine the cause and treatment.
Glaucoma or high eye pressure causes damage to the nerve fibers in the retina resulting in a reduced field of vision. In extreme cases tunnel vision is the result. Detection is easy and performed at every annual eye exam by touching the eye with a measuring device or “puffing air” on the eye. Treatment by drops is usually effective and well tolerated. Occasionally surgery is required to reduce the pressure.

(MD, ARMD-Age Related Macular Degeneration) 10% of people aged 65 to 75 will develop Macular Degeneration. In the 75 to 85 age group it jumps to 30 %. Total blindness is rare. Instead, patients have the central portion of their vision blurred out or distorted. They can see the edges but not exactly in the middle. Much like a normal person being blinded by a flash bulb these people cannot “see what they are looking at”. Retinal exams are the most effective method of predicting the development of this condition. Also Visual Field Testing is available for early detection. Treatment can be nutritional, surgical with laser or injections. People with a close relative with Macular Degeneration are advised to take antioxidant vitamins. Call our office for guidance.

(Blood on the White of the Eye) usually painless and noticed upon rising in the morning or by someone else. Part or sometimes almost the entire white part of the eye is bloody. Maybe associated with physical activity or straining to move or pick up a heavy object. Rarely associated with systemic disease but more common in patients treated with blood thinners. Treatment is a warm compress and time.

A red and painful eye. A truly uncomfortable condition which requires immediate treatment with eye drops.



Contact Lens Basics

Contacts come in many different types.
Below we briefly address the designs and purposes.

Soft Lenses

The most common type of contact lenses come in designs for farsightedness, nearsightedness, astigmatism and even bifocal wearers. While it is always best to remove contacts before going to bed, most are approved for overnight wear for 7 to 30 days depending on which lens you are wearing. Their lifespan can be as short as 1 day or as long as several years. The most practical and cost effective modalities are 2 week and 1 month lenses. These lenses are replaced with a fresh pair at the end of their life cycle and are purchased in “Multi or Six Packs”. One day lenses are an excellent option for the weekend wearer or patients who cannot tolerate traditional lenses due to dryness or allergy. They are available in colors to change or enhance the color of the eye. Time should be taken by the prescriber to carefully choose the best material and fit for each patient. These types of lenses are generally well tolerated and comfortable. They are a good option for most people.

 

Hard Gas Permeable-also called “Hard Lenses”

These hard plastic lenses were the first contact lens design and were suggested by Galileo in the early 1600’s. They were first brought to market in the 1930’s and common by the 1960’s. Today, these lenses are a specialty fit usually reserved for situations where soft lenses will not work. The fitting process is involved and usually takes a few weeks to complete. Somewhat uncomfortable in the beginning hard lenses provide very sharp vision to patients who need them.

ContactLense2



Eye Anatomy

eyeball

The human eye has been called the most complex organ in our body. It’s amazing that something so small can have so many working parts. But when you consider how difficult the task of providing vision really is, perhaps it’s no wonder after all.

How the Human Eye Works

In a number of ways, the human eye works much like a digital camera:

  1. Light is focused primarily by the cornea — the clear front surface of the eye, which acts like a camera lens.
  2. The iris of the eye functions like the diaphragm of a camera, controlling the amount of light reaching the back of the eye by automatically adjusting the size of the pupil (aperture).
  3. The eye’s crystalline lens is located directly behind the pupil and further focuses light. Through a process called accommodation, this lens helps the eye automatically focus on near and approaching objects, like an autofocus camera lens.
  4. Light focused by the cornea and crystalline lens (and limited by the iris and pupil) then reaches the retina — the light-sensitive inner lining of the back of the eye. The retina acts like an electronic image sensor of a digital camera, converting optical images into electronic signals. The optic nerve then transmits these signals to the visual cortex — the part of the brain that controls our sense of sight.

Content from: All About Vision. See more at their website.