case study

To estimate peripheral vision, use the confrontation test. While positioned about 1 m away at eye level, have the patient cover the right eye while you cover your left. Look at each other. Move your wiggling fingers into the center from the side. Have the patient say when the fingers are first seen. Both of you should see them at the same time. Test the nasal, temporal, superior, and inferior fields.

To do an external examination of the eyes, perform the following.

• Systematically examine the external eyes, starting with the surrounding structures and moving in.

Assess the two major surrounding structures.

• First, inspect the eyebrows for size, extension beyond the eye, and hair texture.

Second, inspect the orbital area for edema, puffiness, or sagging tissue below the orbit. Observe for oval, yellowish, and periorbital lesions called xanthelasma, a sign of a lipid metabolism disorder.

• Examine the eyelids for these nine factors.

• First, inspect the lightly closed eyelids for fasciculations or tremors, a sign of hyperthyroidism.

Second, observe the ability to open the eye lids wide and close them completely.

Third, check the eyelid margins for flakiness, redness, and swelling.

Fourth, look for the eyelashes to curve away from the globe.

Fifth, note the upper eyelid position with the eyes open. If one eyelid covers more of the iris or covers the pupil, the patient has ptosis, which should be recorded as the difference between the two eyelids in millimeters.

Sixth, note eyelid eversion or inversion. Ectropion and entropion are abnormalities.

Seventh, observe for a sty or crusting, which may result from infection.

Eighth, note whether the eyelids meet completely and fully cover the globe when the eyes are closed.

Ninth, palpate the eyelids for nodules, which are not usually present.

• Palpate the eye itself. A very firm eye that resists palpation may indicate glaucoma or a retrobulbar tumor.

Inspect the conjunctivae and note their appearance.

• To assess the lower conjunctiva, have the patient look up while you pull down the lower eyelid.

To assess the upper conjunctiva, have the patient look down while you pull the eyelashes down and forward. Evert the eyelid on a cotton-tipped applicator. Remember to perform this assessment only if a foreign body may be present.

Expect the conjunctivae to be clear and have no erythema, exudates, hemorrhage, or abnormal growths (e.g., a pterygium).

• Examine the cornea in two ways.

• Check the cornea for clarity by shining a light tangentially on it. The cornea should appear clear. A corneal arc or circle may be a sign of hyperlipidemia.

Then check corneal sensitivity and CN V by touching a cotton wisp to the cornea, which should cause a blink.

• Assess the iris and pupil, noting five characteristics.

• First, inspect the iris, which should be clearly visible. Usually, the irides are the same color.

Second, observe the pupils’ size and shape. They should be round, regular, and equal in size.

Third, test the pupils’ response to light directly and consensually. The pupils should constrict simultaneously.

Fourth, perform the swinging flashlight test. Shine the light in one eye and then rapidly swing it to the other eye. If the second eye to be tested continues to dilate rather than constrict, an afferent pupillary defect is present, which suggests optic nerve disease.

Fifth, test for accommodation. After looking at a distant object and then focusing on an object 10 cm from the nose, the pupils should constrict.

• Inspect the lens, which should be transparent.

Observe the sclera, which should be white and visible above the iris only when the eyes are wide open. Yellow or green sclera may signal liver disease.

Finally, inspect and palpate the lacrimal apparatus.

• On inspection, the puncta should look like slight elevations on the nasal side of the upper and lower eyelid margins.

On palpation, if the temporal part of the upper eyelid feels full, evert the eyelid and inspect the lacrimal gland. It should not be enlarged.

To examine the extraocular muscles, perform the following.

• Eye movement is controlled by six extraocular muscles and CNs III, IV, and VI. To evaluate eye movement, use four techniques.

• First, have the patient watch your finger move through the six cardinal fields of gaze. Sustained or jerking nystagmus should not occur. But keep in mind that a few beats of horizontal nystagmus may normally occur.

Second, have the patient follow your finger vertically from the ceiling to the floor. The globes and upper eyelids should move smoothly without eyelid lag or exposure of the sclera.

Third, test extraocular muscle balance using the corneal light reflex. With the patient looking at a nearby object, shine a light on the nasal bridge. The eyes should converge and reflect the light symmetrically.

Fourth, if the corneal light reflex is imbalanced, perform the cover – uncover test. As the patient stares at a fixed point nearby, cover one eye and observe the uncovered eye. Then remove the cover and observe that eye as it focuses on the object. Note any eye movement.

To do the ophthalmoscopic examination, perform the following.

• Use an ophthalmoscope to inspect the interior of the eye and follow these guidelines.

• To promote pupil dilation, dim the lights. Instill a mydriatic, if needed.

To examine the patient’s right eye, use your right eye and hold the ophthalmoscope in your right hand. For the patient’s left eye, use your left eye and hold the ophthalmoscope in your left hand.

For stability, put your free hand on the patient’s shoulder or head.

To change the ophthalmoscope lens, use your index finger. Start with the lens set at zero and adjust it as needed.

To avoid tiring the patient, give short breaks from the bright light.

• Perform an ophthalmoscopic exam by visualizing each structure.

• Aiming the ophthalmoscope light at the pupil from 30 cm away, visualize the red reflex. Stay alert for opacities that look like black densities.

Next, move in to visualize the fundus (or retina). It should appear yellow or reddish pink, depending on the patient’s pigmentation. It should have no light or dark areas except for crescents or dots at the disc margin. At any given time, you will see only a small part of the retina. An easy way to find your way around the fundus is to follow the branching of the blood vessels and remember that they always branch away from the optic disc.

Then observe the retinal vessels, noting venous pulsations and any abnormalities at the sites where arterioles and venules cross.