Ophthalmology has evolved substantially over the past decade. Innovations in surgical techniques and tissue banking as well as developments in ophthalmic surgical devices and implants, allow an increasingly sophisticated approach to ophthalmic surgery. Advances in imaging the microanatomy of the eye facilitate diagnosis and guide treatment. Nonetheless, the majority of diagnoses in ophthalmology can be made after a targeted history and careful examination without the need for sophisticated equipment.
Evaluation of the eye and its adnexa requires a good history, assessment of visual function and physical examination of the eyes. Occasionally, special examinations may be required to identify specific ocular disorders or to establish the presence of associated systemic disease.
The basic equipment required for an eye examination by a nonophthalmologist includes the following: (1) a visual acuity chart, (2) a handheld flashlight, (3) an ophthalmoscope, and (4) 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%.
In addition to eliciting a chief complaint, determining whether visual loss is monocular or binocular, central or peripheral, and painful or painless is important.
Prior ophthalmic history (including known ophthalmic conditions, prior eye surgery or trauma, history of contact lens use, and relevant family history) should be obtained.
A review of past medical history and all medications should be included as well.
Central visual acuity, using the patient’s glasses if available, should be determined in all patients. The Snellen chart is most commonly used. The patient faces the test chart at a distance of 6 m (20 ft). Each eye should be tested separately. Visual acuity corresponds to the smallest line the patient can read. The patient who is unable to read the largest letter on the chart (typically a 20/200 letter) should be moved progressively closer until that character can be read and that distance recorded in the chart. If no letters are recognizable, the patient should be tested for the ability to count fingers, see hand motion or perceive light. If a vision chart is not readily available, the ability to read small print or a name badge can provide useful information. Preschool children or illiterates can be tested with the 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 ...