It is recommended that the eyes be checked every two years. Early determination of any abnormalities and degeneration prevents advanced deterioration and allows for early treatment.
An optometrist is a licensed professional who provides primary eye care. This includes examination, diagnosis, and treatment of focal distance issues (nearsightedness and farsightedness), unusual curving of the cornea (astigmatism and cylinder), as well as presbyopia. This condition, associated with aging, is the loss of the ability to focus clearly on objects up close. Eye diseases such as glaucoma, cataracts, and diabetes-related eye conditions are also diagnosed at this level of vision care.
An ophthalmologist is also licensed to perform each of these services, but is an actual medical doctor in the field of vision care. Most are involved in the continuing research in detection and prevention of various eye conditions. Accordingly, the ophthalmologist is able to provide treatment beyond that of the optometrist.
Online eye exams are available on the internet. While some are merely games or gags, others actually do a decent job of assessing a near accurate diagnosis of vision level. There are only two types of tests available without the use of specialized instruments. These are focal vision and color blindness.
A quality online eye exam will take into account the many variables when using a computer to perform a vision check. These include, size of display screen, screen resolution, and distance to stand from the computer while testing. In some exams, a second person is needed to stand at the computer and select the next in the series of screens, as well as provide feedback as to affirm or correct the viewer’s interpretation of the given letters.
A more in-depth online eye exam will have a legend, like a map. This line of standardization is placed above the top row of the eye chart and needs to be measured in centimeters. That measurement will then be scaled to the number of feet a person needs to stand back from either the computer screen or the printed page of the chart.
Detailed directions should include that the exam be done on each eye separately and give specific information as to how much of a line constitutes accuracy. Equivalent vision acuity should be easily determined.
Additionally, some sites offer a test with specific directions and questions to be answered about an image displayed. Yes or no answers to each question signal a potential eye problem that needs to be assessed by a professional.
The types of tests which cannot be given online are:
- Visual field test—assessing peripheral vision loss and indicators of early glaucoma
- Cover test—allows for observing the eye movement while focusing on distant objects in order to identify lazy eye, depth perception, and other conditions
- Slit lamp test—the internal structure of each part of the eye is observed through a microscope
- Eye pressure exam—a puff of air is blown into each eye to calculate eye pressure resistance; this is used in diagnosis of glaucoma and drops are necessary to numb the eye for glaucoma testing
- Dilation—requires eye drops and allows for better viewing inside the eye through the pupil
Online eye exams are only preliminary and far from comprehensive. If use of one indicates even slight vision problems, it is advisable to see an eye doctor.