The conversion of visual acuity E-word table and C-word table is as follows:

5.2 in C-word table is 1.5 in E-word table.

5.1 in the C word table is 1.2 in the E word table.

5.0 in the C word table is 1.0 in the E word table.

4.9 in the C word table is 0.8 in the E word table.

4.8 in the C word table is 0.6 in the E word table.

4.7 in the C word table is 0.5 in the E word table.

4.6 in the C word table is 0.4 in the E word table.

4.5 in the C word table is 0.3 in the E word table.

4.4 in the C word table is 0.25 in the E word table.

4.3 in the C word table is 0.20 in the E word table.

4.2 in the C word table is 0.15 in the E word table.

4.1 in the C word table is 0.12 in the E word table.

4.0 in the C word table is 0.10 in the E word table.

Extended information

The difference between the E-shaped visual acuity chart and the C-shaped visual acuity chart:

At present, the standard viewing angle used in visual acuity charts at home and abroad is lt; 1'( 1 minute viewing angle), the design of the "E" visual mark is based on the square as the surrounding range size, the square E-shaped visual mark, and double openings in 4 directions. The "C"-shaped optotype uses a circle as its peripheral range size, and the ring-shaped C optotype has a single opening in 8 directions. Therefore, in terms of the auxiliary judgment of direction and glyph shape, the difficulty of the C-shaped table is slightly more difficult than that of the E-shaped table.

Our country has always used the E-shaped eye chart, while the internationally accepted eye chart is the C-shaped eye chart. Theoretically speaking, the ring-shaped optotype is more reasonable than the "E"-shaped optotype. Since the three types of vision charts currently approved in our country (logarithmic distance chart 5M, standard near and far charts, and standard near chart 30CM) all use "E", they are still used in order to be consistent with past standards.

Baidu Encyclopedia-c Vision Chart

Baidu Encyclopedia-E Vision Chart