Evaluation of the eye and its adnexa requires a good history,
physical examination of the eyes, and assessment of visual function.
The history should include general information about the patient’s
age, occupation, and health status as well as ocular complaints.
Occasionally, special examinations may be required to identify specific
ocular disorders or to establish the presence of associated systemic
The basic office equipment required for a routine eye examination
by a nonophthalmologist includes the following: (1) a handheld flashlight,
(2) a binocular magnifying loupe, (3) an ophthalmoscope, (4) a visual
acuity chart, and (5) a tonometer.
The basic medications required for an eye examination are (1)
a local anesthetic such as proparacaine 0.5% or tetracaine
0.5%; (2) fluorescein strips; and (3) dilating drops, such
as phenylephrine 2.5% or tropicamide 0.5–1%.
Determination of central visual acuity should be part of the
routine examination of the eye in all patients. The Snellen chart
is most commonly used. The patient faces the test chart at a distance of
6 meters (20 feet). The patient is tested by occluding one eye and
measuring the vision in the opposite eye. Visual acuity corresponds
to the smallest line the patient can read and is recorded as 20/20,
20/30, 20/40, 20/50, and so on. The patient
who is unable to read the large letters at the top of the chart
(typically a 20/200 letter) should be moved progressively
closer until the characters can be read, with the distance between the
patient and the chart recorded as the numerator. If the patient
wears eyeglasses for distance, the visual acuity should be repeated
with the glasses on and the results recorded as uncorrected vision
and corrected vision. Preschool children or illiterates can be tested
with the illiterate E chart or Allen picture chart.
Confrontation visual fields can be used to detect gross visual field
defects such as quadrantanopia, hemianopia, or severe visual field
constriction. With one eye occluded, the patient is asked to fixate
on the examiner’s face and detect finger count or hand
motion in each quadrant. Formal visual field testing (perimetry)
is used to more carefully examine the central and peripheral visual
fields. The technique is performed separately for each eye and measures
the function of the retina, the optic nerve and intracranial visual
pathway. Perimetry relies on subjective patient responses so results
will depend on the patient’s alertness and cooperation.
Several methods are used to assess visual field functions, including
the tangent screen, Goldmann perimetry, and computerized automated
Tonometry measures intraocular pressure. The most common instruments
used are the Tono-Pen and the Goldmann applanation tonometer. The
normal intraocular pressure varies between 10 mm Hg and 20 mm Hg.
Intraocular pressure (IOP) measurements can vary slightly with corneal
Anterior Segment & Adnexa