Chapter 37

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 disease.

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%.

### Visual Acuity Testing

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.

### Visual Field Testing

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 perimetry.

### Tonometry

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 thickness.

### Inspection of Anterior Segment & Adnexa

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