Ophthalmologists and optometrists are trained to perform eye exams. Eye examinations are done to make sure there are not any eye diseases or refractive errors present. Refractive errors mean that a person needs a correction in order to see clearly such as being nearsighted (myopia), farsighted (hyperopia), astigmatism (eye is shaped more like a football than a basketball), or presbyopia (inability to focus from far to near). A thorough or comprehensive eye exam can take over an hour to complete.
History of Present Illness or Chief Complaint
The eye doctor or one of the technicians will take a history of any eye complaints or problems. It is important to take a thorough history of any problems or complaints. The history is very helpful in helping the doctor diagnose any eye condition.
Past Ocular History, Past Medical History, Allergies, Review of Systems, Family History, and Social History
The past ocular and medical history is important as there are many diseases that have systemic and ocular associations. Diabetes is the number one leading cause of blindness in people under age sixty in the United States. Allergies need to be known especially if a medicine needs to be prescribed. Family history needs to be obtained as there are many eye diseases that have a genetic origin. Social history is important as well.
Please bring a list of any current medications that you are taking. If the doctor needs to prescribe a medication, they need to know what medications you are presently taking to make sure there are not any conflicts.
The vision is always checked at every visit. An eye chart or computer screen containing letters, numbers, figures, or Es is displayed. Each eye is tested individually. A card can be used for measuring near vision. There are other more sophisticated methods of measuring the vision if indicated such as glare and contrast sensitivity.
The pupils are examined to test for their reaction to light and accommodation. The pupil reaction can be a very helpful test in many eye diseases.
The eyes will be checked for alignment and proper muscle function. This especially important in young children as any eye deviation needs to be diagnosed early.
Confrontation Visual Fields
The side vision is checked by having the patients respond to the presentation of fingers in their side vision. Any loss of side vision should be investigated to determine its etiology.
A refraction is the part of the eye exam where you are placed behind a machine (phoropter) that contains lenses to correct the vision. Some of the newer phoropters are computerized. Retinoscopy is some times used to get a starting place for the refraction. A light is shown into the eye and return reflex is evaluated as lenses are turned in the phoropter. An autorefractor or aberrometer may be used to help determine your refractive error. An autorefractor is a computerized retinoscope which can quickly analyze the eye. An aberrometer is a computerized wave analyzer that gives a very accurate reading. These machines are also used to customize a refractive surgery such as Lasik.
Slit Lamp Examination
A slit lamp is microscope that allows the eye doctor to get a magnified view of the eye. This instrument is just like any other microscope with the doctor looking through a set of oculars at the eye. The doctor will examine the different structures of the eye such as lids, conjunctiva, cornea, sclera, iris and lens. After the eye is dilated this instrument can also be used to examine the structures inside the eye such as the optic nerve, retina, macula, choroid, and vitreous.
The intraocular eye is measured to help determine if a person has glaucoma. There are a variety of instruments that can measure the eye pressure. Air-puff method uses a non-contact system where a short puff of air is applied to the eye and it then calculates the pressure. Goldmann applanation is the standard method for measuring the intraocular pressure. A yellow fluorescein dye and topical anesthetic are instilled onto the eye. A blue to light is used to shine on the eye and the tonometer is placed against the cornea and the eye pressured is measured. Tonopen is another instrument used to measure the eye pressure. After an anesthetic eye drop is placed on the eye, the tonometer is lightly tapped on the surface of the cornea to measure the eye pressure.
Fundus Exam or Dilated Exam
The pupil is dilated with eyes drops in order to get a complete view of the retina in the back portion of the eye. These drops could take up 30 minutes or more depending on the type and strength of eye drops used. A dilated eye exam is important otherwise the doctor will not be able to examine the retina fully. Your eyes will remain dilated for a few hours and in some rare cases as long as the next day. It is important to bring sunglasses as the light will be very bright. If you don’t have sunglasses, the doctor’s office can provide you will some disposable sunglasses.
If the eye doctor needs more information in order to diagnose a problem or disease, there are other tests that may be performed such as a visual field test (a instrument that tests the side vision), color vision, OCT (instrument that can scan different structures and layers of the eye in very high resolution), topography (measures fine details of the shape of the cornea), fluorescein angiogram (dye is injected into a vein in the arm and pictures are taken of the retina to watch the dye flow through the eye), and other tests.
A comprehensive eye exam is very important part of maintaining a person’s overall health. Many eye diseases and systemic diseases have common associations and relationships. Many times an eye exam discovers an underlying and unknown medical condition. It is very important that you have someone accompany you to the eye doctor’s office as your eyes need to be dilated and you should not drive until the dilation has reversed. You will also receive a prescription for eye glasses if needed.