What are the parts of the eye examination?
Eye examination: what to expect?
Eye examination is one of the best ways to protect the vision because it can detect eye problems at the very beginning, when they are still easy to treat. Regular eye examinations can help you to correct adjust to the changes in the vision on time. While examination your ophthalmologist will advise you how to protect vision or alleviate eye disorders.
What does the eye examination includes?
A comprehensive eye examination includes a series of tests to assess your vision and to confirm the existence of eye diseases. None of those tests is painful. Your ophthalmologist may use unusual instruments to you, direct bright lights right in your eyes or ask of you to look through an almost infinite number of lenses. Each of these searches examines a different aspect of your vision.
Examination of the eye usually starts with questions about medical historiy and any problems related to eyes you may feel.
Subsequently, an ophthalmologist with special lamp does a quick view of an eye, in order to determine whether the outer parts of the eye look orderly and have normal function.
Then the visual acuity is measured, it is examined whether you need glasses, and whether you have any signs of eye disease.
Certain parts of the examination, such as taking medical history and initial examination of the eye can do a nurse who helps ophthalmologist.
Common tests during the eye examination
Examination of the eye includes much more than the vision test. Also, if the examination determines that you need glasses, it will be needed to determine the strength of glass lens that will allow sharper vision. Additional tests evaluate the appearance and function of all parts of the eye.
Testing eye muscle function
This test is done in order to examine the muscles that drive the eyes, searching for their possible weakness or poor control of the nerves that control their movements.
Ophthalmologist looks at your eyes while you move them in eight different directions following the movement of an object, such as a pen.
Testing of visual acuity
Visual acuity is the abilityof the eye to clearly see two separate points. With this test it is examined how clearly can we see from a distance. Ophthalmologist will ask you to read various letters on the board six meters away from you. Font size on the panel decreases from top to bottom. You will cover one eye and read outloud, and then you will repeat the same with the other eye covered.
Investigation of refraction of the eye
Refraction of the eye is the refraction of the light when passing through the cornea and lens. Refractive eye examination allows your ophthalmologist to determine the best combination of lenses to correct refractive errors, that is, to allow you the sharpest vision. If you do not need correction lenses, that is, if you do not have a refractive error of the eye, it is not necessary to do refractive eye examination.
Ophthalmologist may use a method called skyascopia. During that ophthalmologist is sitting opposite the respondent and with the mirror directs the light comin from the lamp, behind the head of the respondent. Through the opening of the mirror he is watching the reflection of light from the pupil and the movement of reflection.By using different lenses, he determines the size of refraction. Repeating this action several times, he finds the combination of lenses that allows the sharpest vision. As preparation for skyascopia, it is necessary to widen the pupil previously byt instilment of special drops (eg, atropine, homatropin …)
Today it is used manual and computerized refractometers. For them it is usually not necessary to pre-expand the pupil.
Examination of the visual field (perimetry)
Visual field is an area that we see when looking straight ahead without moving eyes. Perimetry tests the limits of the visual field, and the existence of flaks in the visual field, particularly in the areas of peripheral vision, i.e in the peripheral areas of the visual field.
There are many different ways of testing the visual field:
– Investigation of visual field by confrontation
Ophthalmologist is sitting in front of you and asks you to hand cover one eye. Then you follow his hand moving from the periphery to the center. Say out loud when you saw his hand.
You are sitting at a small distance from projection sheet and look at the center of circl shown on it. You say when you’ve noticed the appearance of that circle.
It is perimetry which is performed with the help of computers. Ophthalmologist or nurse is using a computer program that displayes little flashes of light while looking through the instrument. Press the button when you notice the flash. Computer records your responses and prints them on paper. Thus arises a graphical representation, or a kind of map of the visual field.
Map of the visual field helps ophthalmologist to establish whether you have any excesses in the visual field. The appearance of these excesses on the map of the visual field is for some diseases very distinctive.
Biomicroscope is the microscope, which with the help of a strong light gets magnified and illuminated image of the front of the eye. Biomicroscope is used to view the cornea, iris, lens and eye front bedrooms. During the examination it can be used eye drops containing fluorescein color. It is orange color, which can show an injury, foreign bodies and corneal inflammation. Tears quickly rinse that color from the eye.
Overview of the retina (ophthalmoscopia)
Overview of the retina or simply ophthalmoscopia includes the examination of the fundus which includes retina, optic disk (which is the visible part of the optic nerve) and blood vessels that feed the retina. Before this examination the pupils must be extended by special drops. Those drops can cause unplesant burning in the eye or cause taste of drugs in the mouth because they drain together with tears through tear channels in the throat. After giving drops, one or more techniques for observing fundus is being used:
– Direct ophthalmoscopia
Ophthalmologist uses a handheld ophthalmoscop and directs the beam of light through the pupil. Before this test drops are not always necessary for the expansion of the pupils. Sometimes after this test you will see after a few minutes the so-called paimages: you will see a bright spot though althought the light is not directed to your eye. This phenomenon is normal and it will soon cease of itself.
– Indirect ophthalmoscopia
For this test you must lie on the bed for examinations. Ophthalmologist looks at each eye with the help of light that is placed on his head, and resembles a miner’s lamp. This way it is possible to see nearly the entire eye background, and obtaine a three-dimensional image. How ithis light is much stronger than that used in the direct examination, it is likely to see paimages, but they quickly disappear.
– Biomicrospic examination
The method used by biomicroscope together with a special lens. Biomicroscope shows much more detailed picture of fundus in relation to the direct and indirect ophthalmoscopia.
Overview of the retina takes 5-10 minutes, but if you get the drops to spread the pupil, their effect will disappear only a few hours later. Vision will be blurred to that time and you will have problems with sharpening the picture. You may not be able to drive, so make sure you have another way to get home or to work. Depending on the type of work, you may not be able to work while your enlarged pupils don’t shrink again.
Tonometry is used to measure the intraocular pressure. It discover glaucoma, a disease that causes increased intraocular pressure and blindness. Glaucoma can be cured if detected at an early stage.
Methods that can be used for the detection of glaucoma:
– Aplanation Tonometry
This test measures the value of force needed to temporarily flat the part of the cornea. Fluorescein, orange color that is used in biomicroscopia here can be used to better display the cornea. Drops containing the anesthetic are also used. Using biomicroscope, ophthalmologist moves tonometer on the cornea. The procedure does not hurt, and anesthesia is sprinkled through the next two hours.
– Uncontact Tonometry
This method uses a breath of air to measure the intraocular pressure. There are no instruments that will touch the cornea, so you do not need anesthesia. You will feel a slight pressure on the eye, which can be a little uncomfortable, but it only takes a few seconds.
This method is used to measure the thickness of the cornea, which can significantly affect the value of intraocular pressure. After instilment of anesthetic, an instrument transmitting ultrasonic waves is used to measure the thickness of the cornea.
At this examination the patient lies, and the surface of the cornea is anestheticated by drops. Ophthalmologist tells you to raise your hand above yourself and stare into one of your fingers. When you steady your view in that way,, ophthalmologist deposites on the surface of the eye small gadget for measuring intraocular pressure. Measuring only takes a few seconds.
In addition to these basic searches and measurements, you may need some more, depending on your age, medical history and risk for the occurrence of eye diseases.
How to prepare for the examination of the eye?
If you’re going for the first time to the eye examination, or you are a first time with a new ophthalmologist, expect questions relating to the history of the disease. Answers to these questions are of great importance for the diagnosis of disease and risk assessment for the development of disease. Be prepared to give concrete answers to the following questions:
Do you currently have some eye problems?
Have you in the past had some eye problems?
Do you currently wear glasses or contact lenses? If so, are you happy with them?
Have you had any health problems in the past few years?
Do you take any medication?
Do you have allergies to any medications, foods or other substances?
Has anyone in your family had eye disturbances such as cataracts or glaucoma?
Has anyone in your family had diabetes, high blood pressure, heart disease or any other health problems that could affect the whole body?
If you wear contact lenses, bring them to the examination Ophthalmologist will want to check that the lenses fit you best. You will also need to take them of at certain test, particularly at the tests using fluoroscein because it can color some types ofcontact lenses.
Always bring your older eye examination results to the examination, and also other medical findings that could have a relationship with the state of your eyes (eg, laboratory findings, the findings of diabetologist, neurologists, cardiologists).
Taken from: www.medri.hr