Understanding Visual Acuity and Corrective Prescriptions: Is 6/18 and 6/36 Bad for Eyesight?

When dealing with your eyesight, you may encounter various terms and measurements, such as visual acuity and prescriptions. Sometimes these numbers can seem confusing, leading to questions and uncertainties. In this article, we will clarify the meanings of visual acuities like 6/18 and 6/36, along with your right eye's prescription of -2 cylindrical, known as astigmatism. Let's break it down so you can better understand your vision and any necessary corrective measures.

Understanding Visual Acuity Measurements

Visual acuity is a term used to describe the sharpness of your vision. It is typically measured using charts similar to the Snellen chart, where '6/18' and '6/36' are common measurements. Let's explore what these measurements mean:

Visual Acuity: 6/18

'6/18' indicates that a person with normal vision can see what you need to see from 6 meters that a person with normal vision can see from 18 meters. This means that what someone with normal vision can see from a distance of 18 meters, you can only see it from 6 meters. This indicates that your vision is below the standard of normal vision, which is typically considered to be 6/6.

Visual Acuity: 6/36

'6/36' represents worse vision than '6/18.' This means that a person with normal vision can see from 36 meters what you need to see from 6 meters. This significantly indicates that your vision is poor and far below the standard of normal vision.

Understanding Cylindrical Prescription

In addition to visual acuity, your prescription includes details like spherical, cylindrical, and axis values. Your right eye has a prescription of -2 cylindrical, which means you have astigmatism. Astigmatism is a common refractive error that causes the eye’s cornea or lens to be irregularly shaped, leading to blurred or distorted vision.

What is Astigmatism?

Astigmatism is an irregular curvature of the cornea or lens, leading to distortion or blurring of vision. The 'cylindrical' part of your prescription indicates the degree and direction of the astigmatism that needs to be corrected.

The negative sign (-2 in your case) is used to describe the amount of correction needed to compensate for this irregularity. A negative sign with cylindrical correction means that the curvature of the cornea is broadening in a specific meridian, causing distorted vision.

Is Your Vision Serious?

Both '6/18' and '6/36' visual acuities are not overly serious. They indicate that your vision is not very good, but not to the point that it is extremely concerning. While poor vision can be uncomfortable, it is often correctable with glasses or contact lenses.

What Should You Do?

It's important to consult with an eye care professional for a comprehensive assessment. An ophthalmologist or optometrist can provide a thorough examination and determine the best course of action for improving your vision. They can prescribe the appropriate corrective lenses or other treatments that may be needed.

Conclusion

Your vision issues, as indicated by your visual acuities of 6/18 and 6/36 and your right eye's prescription of -2 cylindrical, are manageable and not serious. However, it's crucial to seek professional advice to ensure you receive the best possible care for your eyesight.