Is normal vision 1.0 or 5.0?
Nov 14, 2024
Source: Cainiu Health
Dr. Wang Shuai
Introduction
In general, numerical values alone are insufficient to determine whether an eye is normal or not. Since different vision recording methods have different standards, eyes with vision measurements of 1.0 and 5.0 could both be considered normal. In visual acuity testing using the decimal recording method, the standard for normal vision is 1.0, indicating that an individual can clearly identify the line of characters designated as 1.0 on the vision chart from the standard testing distance.
Generally speaking, simply providing numerical values is not enough to determine whether the eyes are normal. Since different vision recording methods have different standards, eyes with vision of 1.0 or 5.0 could both be considered normal. Detailed explanations are as follows:
In visual acuity testing using the decimal notation system, the standard for normal vision is 1.0. This means that at the standard testing distance, an individual can clearly identify the line of characters corresponding to 1.0 on the vision chart. This is an internationally accepted standard for normal visual acuity.
In China, the commonly used recording method is the five-point notation system, in which the standard for normal vision is 5.0. The five-point notation converts visual acuity into a numerical scale ranging from 4.0 to 5.3 through a specific conversion relationship. In this system, 5.0 is considered the lower limit of normal visual acuity.
Therefore, eyes with normal vision can be recorded as 1.0 using the decimal notation or 5.0 using the five-point notation, depending entirely on the visual acuity recording method used. During vision testing, doctors will select the appropriate vision chart based on actual circumstances and provide the corresponding visual acuity assessment.
In daily life, it is recommended to strictly limit the time spent using the eyes. After prolonged visual tasks, one can close the eyes to rest or perform eye exercises to relax the eyes and relieve visual fatigue.
