Important Things to Know About Vision Tests
Vision tests allow us to measure a patient’s whole vision field. This includes their central vision and side vision. These tests will check the field of vision for each eye by itself. One of these tests is a subjective exam. This means that the patient has to understand the instructions being told to him or her, to cooperate, and to do the whole test so the doctor gets enough information.
Certain types of vision tests
, such as field testing, are used to check for glaucoma damage to the nerves of the eye. These tests also are good for checking for retinal disease, eyelid problems such as ptosis, diseases of the optic nerve, and any disorders that are hampering the pathways of vision in the brain. These pathways transmit data from the eye to the occipital cortex in the brain. This is where the data is processed and makes you see.
Vision tests for the field of vision are done through several means. Most field testing is done on one eye, and with the other eye covered up so there are no errors. In every test, the patient needs to look straight in front of him or her, so that the test is covering the peripheral vision only. Most of these vision tests will now check for fixation; this is the ability of the person to look straight ahead consistently.
Generally, vision tests of this sort are most useful for:
- Glaucoma screening
- Glaucoma patient testing
- Checking for lid droop, esp. to get insurance approval to have this operated on
- Macular disease testing
- Checking for peripheral retinal diseases
- Checking the optic nerve function, to look for tumors, injury, bad circulation or even stroke.
- Check the pathways of vision to the brain. This is looking for tumors, swelling of the brain, injury or bad circulation
One of the vision tests you can do is to make the patient look right in front of them, and have them count the number of fingers shown by the doctor on the side. Most commonly these days, field tests are done with computerized equipment. One eye is normally covered and the person will put her chin in a chin rest. If the patient sees flashing lights at different locations, she will say so, or press a button. The right eye is always tested first in these vision tests, then the left.