What does a spherical equivalent of -1.38D mean?
Nov 14, 2023
Source: Cainiu Health
Dr. Zhao Xiaodong
Introduction
In general, a spherical equivalent of -1.38D indicates that the patient has 75 degrees of myopia. The spherical equivalent is a method of converting astigmatism into a spherical lens with similar optical effect, typically composed of concave lenses, convex lenses, and cylindrical lenses, primarily used to correct refractive errors such as myopia or hyperopia. If the patient experiences any discomfort, it is recommended to seek timely medical attention at a hospital.
In general, a spherical equivalent of -1.38D indicates that the patient has 75 degrees of myopia. The detailed explanation is as follows:
The spherical equivalent is a value that converts astigmatism into a spherical lens with similar optical effect. It is typically composed of concave lenses, convex lenses, and cylindrical lenses, and is primarily used to correct refractive errors such as myopia or hyperopia. In individuals with normal vision, the spherical equivalent is generally 0. Therefore, a spherical equivalent of -1.38D indicates the presence of myopia at 75 degrees, and corrective eyewear is required in such cases.
Clinically, the spherical equivalent serves as a primary criterion for screening and assessing the degree of myopia. By converting astigmatic refractive error into an equivalent spherical lens with similar optical performance, it reflects the overall refractive state of the eye. The value is calculated as the sum of the spherical power plus half of the cylindrical power.
If a patient experiences any discomfort or symptoms, it is recommended to seek timely medical evaluation at a hospital to avoid delays in diagnosis and treatment.
