Blindness and Low Vision: An Overview

Blindness and Low Vision Overview

Key information About Blindness and Low Vision

Blindness and low vision affect a person’s ability to see clearly or see at all, and have various causes, timing and types of onsets, levels of severity – and they impact people’s daily lives differently. Key terms and concepts related to blindness and low vision as as follows:


Blindness is generally defined as a visual impairment in which a person has very limited or no ability to perceive light, shapes, or form. It can be caused by various factors, including eye diseases, injuries, congenital conditions, and neurological factors.

Legal blindness is a criterion defined by governments for eligibility to receive certain benefits and services for individuals with severe visual impairments. In the US, legal blindness is defined as having visual acuity of 20/200 or worse in the better eye with the best possible correction, or having a visual field limited to 20 degrees or less.

Types of Blindness and Low Vision

Blindness can be categorized into various types based on its cause and severity. Various types include:

  • Total Blindness – the complete absence of sight.
  • Partial Blindness – Limited vision or significant visual impairment.
  • Functional Blindness – Visual impairment severe enough to impact daily activities.
  • Cortical Blindness – Damage to the brain’s visual processing centers, resulting in blindness even if the eyes are physically healthy.
  • Color Blindness – Classified into different types based on the specific colors that are difficult to distinguish.

Importance of a Comprehensive Eye Exam

A comprehensive eye exam helps your doctor diagnose vision issues, and the doctor may recommend various types of correction to help you see as clearly as possible. Corrections include, but are not limited, prescription eyeglasses, contact lenses, medications, or other medical intervention.

In addition to diagnosing vision issues, did you know that according to the American Academy of Ophthalmology, “Eye exams aren’t just about vision. They’re about your health. Your eyes are windows to the live action of blood vessels, nerves and connective tissues throughout your body. Problems spotted in the eye are often the first signs of disease lurking elsewhere.” Click here to learn about 20 surprising conditions your eye doctor may detect during a comprehensive eye exam.

The Low Vision Exam

A low vision eye exam is a specialized type of eye examination focused on assessing and addressing visual impairments in individuals with significant vision loss that cannot be fully corrected with traditional eyeglasses, contact lenses, or medical treatments. This exam is typically conducted by an optometrist or ophthalmologist who has expertise in low vision care. The goal of the exam is to maximize the individual’s remaining vision and improve their quality of life.

Areas that are often assessed during a low vision eye exam include:

  • Patient History – A doctor will start by discussing your medical history, the history of your vision loss, any underlying eye conditions, and how your vision impairment affects your daily life.
  • Visual Acuity Testing – Although your vision may be impaired, the doctor will still measure your visual acuity using various tests, such as the Snellen chart and added charts and equipment designed for low vision.
  • Visual Field Testing – This evaluates your peripheral vision and helps determine the extent of your visual field loss. It’s crucial for understanding the scope of your functional vision.
  • Contrast Sensitivity Testing – This assesses your ability to differentiate between objects with varying levels of contrast, which is essential for tasks like reading and object recognition.
  • Optical Devices and Aids – Various optical devices and low vision aids that might help you make the most of your remaining vision will be discussed and tested, including magnifiers, telescopes, tinted lenses, and more.
  • Lighting Assessment – Lighting plays a critical role in enhancing vision for individuals with low vision. The doctor may discuss the lighting conditions in your home or workplace and provide recommendations for optimal lighting setups.
  • Functional Vision Assessment – This part of the Low Vision Exam involves evaluating your ability to perform specific tasks that are vital for daily living, such as reading, writing, using electronic devices, home care, mobility, and much more.

Crucial Importance Of Vision Rehabilitation Services

Based on the findings of the Low Vision Exam, an eye care professional will provide personalized recommendations for low vision aids, devices, and strategies. They may also refer you to vision rehabilitation programs to help you adapt and learn new skills.

Learn more in our recent article Vision Rehabilitation Help and Hope – with information and links to locate resources in your area. Coping with vision loss can be emotionally challenging, so your eye care professional may offer guidance, resources, and emotional support to help you adjust to changes in vision.

more information on Vision and Vision Rehabilitation from VisionServe Alliance

Click here to enjoy all of our recent National Council on Aging (NCOA) and American Society on Aging (ASA) articles with essential information about blindness, vision loss, and vision rehabilitation at. Article topics include:

Blindness and low vision can result from a broad range of factors, including age-related eye diseases such as glaucoma, macular degeneration, diabetic retinopathy, and cataracts. Learn more about these eye diseases.

Blindness and Low Vision can also result from genetic factors, congenital conditions, neurological conditions, infections, accidents, and other eye injuries.

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