How much Change in Refractive Error will Cause a Patient to Seek Ophthalmic Care?

Incredibly, a quantifiable answer for this question could not be readily discovered in the ophthalmic corpus. Although it’s likely that most providers and academic instructors could provide estimates based on clinical experience, a literature review could supply no definite answer for this basic clinical question. 

Even Duke-Elder (System of Ophthalmology) and Borish (Clinical Refraction) are silent on the topic. While it has been qualitatively noted that “substantial change in refractive error…can cause the patient to become aware of a change in vision” and that +0.25 D or +0.50 D of induced reduced refractive error can elicit subjective visual symptoms, the amount of defocus necessary to cause patients to seek ophthalmic care has not been reported to date. The purpose of this brief report is to review observational data in order to provide an initial, quantitative answer to a basic ophthalmic question.