For a patient with a visual acuity of 20/200, which lens power is MOST appropriate?

For a patient with a visual acuity of 20/200, which lens power is MOST appropriate?

• A. +/- 0.50 Diopters
• B. +/- 1.00 Diopters
• C. +/- 2.00 Diopters
• D. +/- 3.00 Diopters

Answer: (B)

When vision is markedly reduced, the first goal is to test a correction that will reveal whether refractive error is driving the blur without overshooting the eye’s focus. A moderate lens power around one diopter is a practical starting point because it’s large enough to produce a noticeable change in acuity if there is a refractive component, yet not so large that you risk overcorrecting and creating new blur or discomfort. Small changes, like 0.50 D, may produce little or no visible improvement, making it hard to gauge the direction and magnitude of the true error. Larger corrections, such as 2.00 or 3.00 D, can overshoot the focus if the actual error is smaller and can complicate the refinement process. The objective is to identify improvement with a sensible, middle-ground correction and then refine further as needed. The sign (plus or minus) depends on whether the patient is hyperopic or myopic, determined via retinoscopy or subjective refinement, but the magnitude of about 1.00 D is a reasonable starting point.

When vision is markedly reduced, the first goal is to test a correction that will reveal whether refractive error is driving the blur without overshooting the eye’s focus. A moderate lens power around one diopter is a practical starting point because it’s large enough to produce a noticeable change in acuity if there is a refractive component, yet not so large that you risk overcorrecting and creating new blur or discomfort. Small changes, like 0.50 D, may produce little or no visible improvement, making it hard to gauge the direction and magnitude of the true error. Larger corrections, such as 2.00 or 3.00 D, can overshoot the focus if the actual error is smaller and can complicate the refinement process. The objective is to identify improvement with a sensible, middle-ground correction and then refine further as needed. The sign (plus or minus) depends on whether the patient is hyperopic or myopic, determined via retinoscopy or subjective refinement, but the magnitude of about 1.00 D is a reasonable starting point.