If you are interested in how the vision is checked, what the ophthalmologist does, how to read and understand the papers received from him, or how to decipher the recipe for glasses or contact lenses, we will try to help you.
An eye exam is performed to detect and evaluate a person's refractive errors (myopia, hyperopia and/or astigmatism).
So, when you came to the ophthalmologist...
How the process goes and what the doctor does
The main goals of the doctor are to check
- objective refraction data
- visual acuity data
- prescribe vision correction if necessary
- If you are over 40, it is advisable to check the intraocular pressure (IOP) for glaucoma screening.
Normal eye exam sequence
With the help of an auto refractometer, the doctor will receive data about the refraction of the eye and the presence of astigmatism.
Using a test chart or an electronic sign projector, the doctor will determine distance visual acuity, and using a special test with text he/she will determine near visual acuity.
In case of refractive errors or low visual acuity, the doctor will determine the necessary optical correction with the help of a trial frame and lenses or a phoropter and write a prescription for glasses or contact lenses.
How to understand the findings of an ophthalmologist
After the eye exam, you will receive objective refraction data and visual acuity data.
This is how the printout from the auto refractometer looks like.
It shows data about refractive errors in the eye.
1 - patient data
2, 3 - R right eye, L left eye
Сolumn S shows the refraction in dioptres (healthy eye is about 0), and columns C and A show the astigmatism level and axis angle.
This data will tell you about the degree of your refractive errors.
4, 5 - data on corneal curvature in dioptres and millimeters, respectively for the right (R) and left (L) eye. These data are not critical for patient understanding.
Based on these data, the doctor will begin to select glasses or contact lenses.
In this case, the doctor will say that the right eye has a slight myopia of -0.5D with moderate astigmatism of -1.25D along the 78- degree axis.
This is the result of the visual acuity check and the recipe for glasses.
In this case (this result is not related to the example above)
The right eye (OD) has high hyperopia (+ 6.75D) and -1.75D astigmatism in the 5-degree axis and shows visual acuity of 0.7-0.8.
The visual acuity was checked in the distance. The near vision acuity at a distance of 40 cm was NOT checked.
Is it possible to order contact lenses according to the prescription for glasses?
If you have a prescription for glasses, you cannot order contact lenses with the same data.
Glasses are calculated based on the fact that they are located at a distance from the eye, and contact lenses are located directly on the cornea. Therefore, the eyeglass prescription must be recalculated by a specialist.
But, you can do it yourself, for example using this online calculator.
Subscribe and learn 15 secrets to help keep your eyesight