Hypoglossal
II Optic Nerve - Visual Acuity
Examination Technique:
each eye is tested separately.
test best corrected vision using eyeglasses.
any patient with uncorrected visual acuity of less than 20/20 should be examined with a pinhole. Improvement of vision through a pinhole indicates that the error is refractive.
test distant vision using a Snellen chart at 10 or 20 feet.
or test near vision using a near vision card at 14 inches.
the patient is instructed to read progressively smaller lines of letters until they can go no further.
Normal Response: most young healthy individuals have vision of 20/20, i.e. at 20 feet, the patient reads a line that a normal eye sees at 20 feet.
record for each eye separately, right eye = OD, left eye = OS.
Abnormal Response: (Examples)
20/30 – 2: The patient missed two letters of the 20/30 line.
20/200: Legally blind. At 20 feet the patient reads a line that a normal eye could see at 200 feet.
CF: If a patient is unable to read the top line, have him count fingers at maximal distance.
HM: If a patient cannot count fingers, ask them to determine direction of hand motion.
LP: If a patient cannot perceive hand motion, see if they can perceive a light.
发表于 2009-7-14 01:22:38
