2020–2021 BCSC Basic and Clinical Science Course™
3 Clinical Optics
Introduction: Quick-Start Guide to Optics and How to Refract
Part 2: How to Refract
At the core of ophthalmic practice is the ability to assess a patient’s visual function. To accomplish this, your capacity to perform an efficient, accurate refraction is critical. Subjective refraction is a clinical art—facility takes time to develop. Learn to refract well.
There are many excuses to avoid refracting almost any patient you see. Refract every patient who needs it. Just because a refraction is not easy does not mean it is not important to the patient or that successful refraction would not greatly benefit the patient. Difficult refractions are an inevitable part of ophthalmology. If necessary, reschedule the difficult patient to allow the additional time.
Carefully adjust the pace of the refraction to the ability of the patient to respond. The patient should not feel rushed, but offer the binary comparisons crisply to encourage the patient to respond based on his or her initial visual impression. The pace should discourage the patient from attempting to accommodate before deciding on the better lens choice.
Cycloplegia (paralysis of accommodation with anticholinergic eyedrops) is indicated whenever there is uncertainty about the accommodative status. This technique should be routine for children below the age of 10 years. (See Chapter 4.)
Many healthy young adults can see 20/15 if given the chance. Don’t settle for 20/20, let alone 20/25. Children below the age of 6 or even 7 years are frequently uninterested in reading past the 20/30 line, even though more sophisticated testing methods have shown that they may possess 20/20 acuity. (That is why many “picture” eye charts stop at the 20/30 line.)
For children under the age of 6 or 7 years, use a chart with “tumbling” E’s, Landolt Cs, or picture targets (see Figure 3-6). Do not rely on a parent’s assurance that the child knows the letters.
There are few opportunities in clinical ophthalmology to improve your patient’s visual function as convincingly as the chance to prescribe a good pair of glasses. Competent refraction is key tool toward developing a patient’s confidence in you.
Excerpted from BCSC 2020-2021 series : Section 3 - Clinical Optics. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.