An eye exam consists of physical evaluation and a series of eye tests to check the vision and find any abnormalities in the structure and function of the eyes. The need for any eye treatment is also evaluated on the basis of these tests and clinical findings. Each eye test during the eye exam is aimed at evaluating a different aspect of the vision and the general health of the eyes.
An eye exam is performed by the ophthalmologist and optometrist by conducting a series of tests to access the vision. The general eye exam consists of external examination followed by various tests for visual acuity, pupil function and the function off the extraocular muscles. Eye exams help in detecting the diseases of the eye , ocular manifestations of systemic diseases, any tumours or potentially blinding diseases.
Regular eye check-up is important as most eye diseases are asymptomatic. An eye exam helps to detect eye problems at the earliest when they can be treated with minimum effort and treatment cost. It also helps to correct vision changes and provide required eye care tips to maintain the health of the eyes.
Several factors like age, general health and risk of developing eye problems determine the frequency of eye exam. For healthy adults, eye check -up should be done every one to three year after the age of 55. Eye tests can be required more frequently if vision problems are present. This may include;
- People having glasses or contact lens
- Family history of eye disorders
- People suffering from systemic diseases which may affect the vision
- People taking medication which may affect the eyes.
- Previous eye injury or eye surgery
- People suffering from diabetes
For children, the eye test is done every one to two years if there are no symptoms and no family history of vision problems.
The routine eye exam should include the following:
- History of the individual health and family history of eye problems.
- Evaluation of near and distance vision using an eye chart
- Near vision test for determining presbyopia and the need for progressive lenses
- Test for checking the coordination of both eyes
- Examination of the optic nerve and eye pressure test
- Test for cataract
- Test for extraocular muscle function
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The eye exam can take upto one hour or more depending on the number and the duration of the tests required by the individual. A variety of tests and procedures can be used to examine the eyes. These tests include:
- Visual acuity test – it is used to check the ability to see the details of letters and symbols from a certain distance. It is performed when there is a problem or change in the vision. This measures how well a person sees at near and far distances. The visual acuity is expressed in fraction. The standard visual acuity is 20/20. If the visual acuity is not 20/20, corrective glasses, contact lenses or corrective eye surgery may be needed. The doctor will look at the result and formulate a required eye treatment
- Visual field test– it is used to determine the peripheral vision. It is to check the presence of blind spots in the peripheral vision which can originate due to eye diseases like glaucoma.
- Colour blindness test – it is a screening test to rule out colour blindness. It is used to find if the person has It also helps to determine the type and the severity of colour blindness. A cover test is most commonly used to detect colour blindness.
- Ocular motility test – problems with eye movements cause eye strain. This affects reading ability and other skills. Ocular motility test is done in order to determine how well the eyes can follow a moving object. Testing for smooth eye movements and quick eye movements is done.
- Stereopsis test- it is used to measure the depth perception and the appreciation of the three-dimensional nature of the objects.
- Refraction assessment– this test is used by the doctor to determine the eyeglass prescription. It is used to determine the level of myopia, hypermetropia, astigmatism and presbyopia During the test, a phoropter is placed in front of the eyes which shows a series of lens choices. The doctor decides the lens power based on the patient’s answers.
- Glaucoma test– this is done by measuring the pressure inside the eyes. Commonly used test is the puff off test. The chin is placed on the machine and a puff of air is directed at the eye. Based on the resistance of the eyes to the puff of the air, the intraocular pressure is calculated. High intraocular pressure signifies the risk of developing glaucoma.
EYE CARE TIPS
Proper eye care tips include:
- Having regular eye check-up
- Wearing protective eyewear in sun
- Resting the eyes
- Limiting the use of computers
- Eating food which is healthy for the eyes