Chapter 5: Eye Exam

INTRODUCTION

The eye exam is performed when a patient presents with an eye concern, not as part of a screening evaluation. Elements of the evaluation (cranial nerve [CN] assessment) are also covered in the neurologic exam. Many components of the eye exam are relatively straightforward and can be capably performed by nonophthalmologists. It is therefore important to practice as much as possible early in your training, working with asymptomatic patients. The most challenging portion of the exam, direct ophthalmoscopy, is covered at the end of this chapter and takes more time and effort to master, although realize that you can gain a lot of information even if you do not feel comfortable with this component.

ASSESSMENT OF VISUAL ACUITY

Assessing visual acuity is critical in determining the severity of an eye concern. For this reason, it is often referred to as the vital sign of the eye. It is the important first step when evaluating an eye issue and when describing concerns to a consultant.

• Assessment can be done with either a standard Snellen wall chart read with the patient standing at a distance of 20 feet or using a specially designed pocket card held at 14 inches (Figure 5-1).

• Each eye is tested independently (ie, one eye is covered while the other is used to read). The patient should be allowed to wear their updated corrective lenses (glasses or contact lenses), and the results are referred to as “best corrected vision.”

• You do not need to assess the patient’s ability to read every line on the chart. If they have no complaints, rapidly skip down to the smaller characters.

• The numbers at the end of the line provide an indication of the patient’s visual acuity compared with normal subjects. The larger the denominator, the worse is the acuity. For example, 20/200 means that the patient can see at 20 feet what a normal individual can at 200 feet (ie, their vision is poor).

• If the patient is unable to read any of the lines (a huge red flag if this is a new symptom), a gross estimate of what they are capable of seeing should be determined (eg, ability to detect light, a waving hand, or number of fingers placed in front of them).

Special Test: Pinhole Testing

Pinhole testing can determine if an acuity problem is the result of refractive error (ie, correctable with glasses) or due to another process. The pinholes only ...