20/200 vision indicates a significant visual impairment, making it challenging to see clearly at a distance. Individuals with this level of vision often find daily tasks requiring clear distance sight difficult.
What 20/200 Vision Means
Visual acuity, the sharpness of vision, is commonly measured using a Snellen eye chart. During an eye exam, a person stands 20 feet from this chart and reads lines of letters that decrease in size. The resulting fraction, such as 20/20 or 20/200, indicates how well someone sees.
Having 20/200 vision means a person must be 20 feet away to see what someone with typical 20/20 vision can see from 200 feet. This level of vision suggests severe myopia, where distant objects appear blurred. It can also be associated with other conditions affecting visual clarity.
Correcting Vision with Glasses and Contacts
For many, 20/200 vision stems from refractive errors like myopia (nearsightedness), hyperopia (farsightedness), or astigmatism. These conditions occur when the eye’s shape prevents light from focusing directly on the retina, the light-sensitive tissue at the back of the eye. Corrective lenses, such as prescription glasses or contact lenses, work by bending light rays to converge on the retina.
Glasses and contacts alter the path of light entering the eye, compensating for focusing imperfections. This allows a clearer image to form on the retina, significantly improving visual acuity. For many with 20/200 vision due to refractive errors, these solutions can effectively restore vision to 20/20 or very close. A 20/200 vision often corresponds to a prescription of approximately -2.5 diopters, though this can vary based on other refractive errors.
Other Correction Options
Beyond glasses and contact lenses, surgical interventions offer methods for correcting 20/200 vision, particularly when caused by refractive errors. Procedures like Laser-Assisted In Situ Keratomileusis (LASIK) and Photorefractive Keratectomy (PRK) involve reshaping the cornea. This reshaping allows light to focus onto the retina, similar to how corrective lenses function.
LASIK creates a thin flap in the cornea before a laser removes tissue underneath, while PRK reshapes the corneal surface directly after removing its outer layer. These procedures aim to reduce or eliminate the need for glasses or contacts, offering a more permanent solution for suitable candidates. Refractive Lens Exchange (RLE), which replaces the eye’s natural lens with an artificial one, is another option, especially for severe refractive errors or presbyopia.
When Full Correction Isn’t Possible
While glasses, contacts, and refractive surgeries can correct 20/200 vision caused by refractive errors, full correction to 20/20 is not always achievable. This occurs when vision impairment results from underlying eye diseases or conditions affecting the eye’s structure or function beyond simple focusing issues. Examples include age-related macular degeneration, which impacts central vision, cataracts that cloud the eye’s lens, or glaucoma, which damages the optic nerve.
Diabetic retinopathy, retinitis pigmentosa, and certain congenital conditions can also lead to uncorrectable vision impairment. In such cases, individuals may experience “low vision,” defined as a permanent visual impairment uncorrectable by conventional means. If vision remains 20/200 or worse in the better eye even with the best correction, or if there’s a significant restriction in the field of vision, a person may be classified as “legally blind” in many regions.