Technicians perform an array of visual tests before the doctor even sees the patient.
Contrary to what many think, the eye examination does not start when the patient’s vision is first checked. It begins when the patient is called from the reception area and into the examination room. At this time, an alert technician should notice if the patient has any visual problems. Does the patient bump into objects in the waiting room such as end tables or trash bins? Did the patient arrive alone or with another person? If the patient is alone, and having trouble walking, then the technician should walk up to the patient, place a hand on her shoulder, and ask if she requires assistance moving about the office. It is extremely important to ask the patient’s permission first, since many visually impaired people are very independent, and do not want the help. My rule of thumb is to treat the patient the way you would like to be treated when having a medical exam.
During the history portion of the eye exam, it is very important to not only listen to what the patient is saying, but also to be aware of what the patient is not saying. Be cognizant of the patient’s body position, and posture. If, while talking to the patient, you notice that he constantly holds his head tilted toward the shoulder, the patient may have a back or neck problem, or may potentially have an eye turn and double vision that is lessened when the head is in this position.
VISUAL ACUITY ASSESSMENT
To measure the clarity or clearness of the patient’s vision, place the patient at a fixed distance, about 20 ft., from the eyechart (the Snellen chart is most commonly used). After covering one eye, the patient should be directed to read the smallest line of letters that she is able to discern with the uncovered eye. Information from this portion of the evaluation can provide valuable clues to the patient’s eye problem and can assist the physician in making a diagnosis.
If the acuity is 20/40 or less, the technician should perform the pinhole test to determine whether reduced visual acuity is due to a refractive error or to a vision disorder. The pinhole eliminates the peripheral light rays, so if the decreased vision is due to refractive error, the patient will have improved vision. The test is performed while the patient is wearing glasses or contact lenses. The occluder covers one eye, and allows vision through the other. After asking the patient to read the smallest line discernable, the pinhole is placed over the open eye. The patient is asked once again to read the smallest line on the eyechart. The procedure is repeated for the other eye.
The technician should make sure that the testing conditions are annotated in the patient chart. If the patient was wearing spectacles or contact lenses, it should be noted.
•”CC”= with correction
•”SC”= without correction
•”SCL”= with soft contact lenses
•”HGP”= with gas permeable contact lenses
The type of testing target should also be documented, such as the number chart, picture chart, tumbling “E” chart, etc.
COLOR VISION TEST
This test utilizes plates made up of dot patterns that form a number on a background of randomly mixed colors. If the patient has normal color vision, she should be able to distinguish the number shown in the dot pattern. If the patient does not have normal color vision, she will just see the randomly mixed dots, but no number. It is important to remember that this test is performed with glasses on and each eye must be tested separately.
The grid pattern is used to document and detect vision changes that affect the central vision field, such as macular degeneration. The test is performed with the patient correction (distance or reading glasses, or contact lenses) and the test card is held at reading distance. Each eye is tested individually, and the patient should be instructed to cover one eye and look at the grid pattern. The patient should be instructed to report any irregularities in the grid pattern such as wavy, blurred lines, missing areas, distortion, or gray areas. The technician should document those areas on the test grid, then repeat test for the other eye.
There are six muscles attached to the outside of each eye. Two move the eye horizontally and the other four work to move the eyes in the other directions of gaze. This test evaluates the muscles that move the eye in the various directions of gaze. The patient should be instructed to keep both eyes open and follow the examiner’s finger without moving his head. The patient is then asked to look in the nine diagnostic positions of gaze: Straight Ahead; Horizontally Left; Up and Left; Up; Up and Right; Horizontally Right; Down and Right; Down; and Down and Left. The patient follows a target to various points of gaze while the examiner closely monitors their eye movements. Any limitation in eye movement should be documented for the doctor.
CONFRONTATION VISUAL FIELD
This is a gross estimation of the patient’s visual field. The patient is directed to look at a fixation point, such as the examiner’s eye, while covering the fellow eye. The examiner moves her finger from the peripheral side of the patient toward the patient midline of the face and asks the patient to indicate without moving her head and keeping fixation, when she is initially able to see the finger. All four quadrants (upper, lower, temporal, and nasal) should be tested and any restriction should be documented in the patient chart.
This assessment can provide clues about overall health of visual pathway and is useful in detection of neurological abnormalities. First, the pupil size is measured in millimeters. Next, the room’s lights are dimmed and the patient is instructed to fixate on the far wall. The pupils are observed as a bright light is shined into the patient’s eye from slightly below the eyes. The examiner documents the pupil’s response to the light. A normal response is constriction of the eye that the light is shined in, and also constriction of the fellow eye. The light then should be swung from one eye to the other (making sure the angle and amount of time of light exposure is equal for both eyes), and a comparison of the pupil response is noted. A normal test has both eyes constricting normally when the light is swung from one eye to the other. An abnormal test will show one eye constricting when the light is introduced, and when the light is swung to the other eye, the pupil dilates. This phenomenon is known as an Afferent Pupillary Defect and should be documented in the patient’s chart. The technician should also inform the doctor so that he can examine the patient prior to any eyedrop instillation. It is extremely important for the technician not to instill any dilating drops into the patient eye because once the eye is dilated; the pupil reaction to light can no longer be obtained. OO
Janet Hunter, president of Eye Source, LLC, specializes in ophthalmic technician training.