What are Eye Tests?
Eye tests, also called eye examinations or ophthalmic examinations, are simple diagnostic procedures performed as part of a health and wellness check-up, or as a routine examination to ensure you have proper eyesight and no eye diseases, disorders or infections.
Eye tests may differ slightly for different age groups but the common purpose is to assess your ocular health and detect any vision-related problems for early intervention. Eye tests become more important once you pass 40, as your eyesight begins to show gradual signs of ageing.
What are the Indications for Eye Tests?
Eye tests are recommended for people with a family history of eye disorders or vision-related problems. If you notice any unusual symptoms, you can schedule a visit to your nearest ophthalmologist or eye specialist to get an eye check-up.
How to Prepare for an Eye Test
Find a reputable eye specialist or optometrist near you. Carry your glasses, contact lenses and drug prescriptions when you visit your specialist. Also bring sun-protection goggles, as some tests may make your eyes light-sensitive and you may briefly require sun protection afterwards for enlarged pupils.
What are the Different Eye Tests?
Your eye doctor or an office staff member will ask you about your medical and vision history. Based on these details, you will be subjected to a set of tests.
Below is a list of some common eye tests and examinations. There may be certain modifications to this list based on your doctor’s discretion.
- Visual Acuity Test: This is a very common test to detect near-sightedness (myopia) and far-sightedness (hyperopia). In this test, you sit in front of an eye chart, with letters that get smaller as you read down each line. You are asked to cover each eye alternately and use the other eye to read aloud moving down the chart, until you can't read the letters anymore.
- External Exam and Pupil Reactions: Your doctor watches how your pupils adjust to light and objects near you. At the same time, the sclera (the white part of the eye) and the position of your eyelids is also checked.
- Eye Dilation: Eye drops are administered in your eyes to make your pupils bigger.
- Eye Muscle Movement Test: In this test, your eye specialist makes you focus on a few stationary and mobile objects that are placed in different directions. Then your eye movements are observed to check your eyes’ alignment.
- Refraction Test: This is performed if you wear or need corrective lenses. In this test, your doctor may use a computerized refractor (phoropter). You are asked to look through the refractor while it flips back and forth. Meanwhile, the amount of light reflected by your retina is measured
- Slit Lamp: This test uses a device called a biomicroscope that magnifies and lights up the front of your eye. It is used by your eye specialist to inspect your cornea, iris, lens and the back of your eye.
- Ophthalmoscopy: This is a retinal examination. In this test, your optometrist dilates your pupils and uses an ophthalmoscope to check the back of your eyes which includes the retina, retinal blood vessels, vitreous fluid and the centre of your optic nerve.
- Pachymetry: This test measures corneal thickness through ultrasound, and is done for people who require corneal surgery.
- Glaucoma Tests: These tests measure the pressure in your eye, also called intraocular pressure (IOP). Abnormally high pressure indicates glaucoma.
Tests for glaucoma are quick and painless. Some of them include:
- Applanation Tonometry: In this test, you are given eye drops to numb your eyes. Then you are instructed to stare straight ahead. A device called an applanation tonometer is gently applied to the surface of each eye to measure the intraocular pressure.
- Non-contact Tonometry: In this test, you are told to stare at a target as the non-contact tonometer emits a mild puff of air into each eye. The resistance offered by your eye to the flow of air indicates the IOP.