What Is Contrast Sensitivity?

Visual acuity — the familiar “20/20” measurement — tells you how small a high-contrast letter you can identify on a bright, evenly lit chart. Contrast sensitivity is different. It measures how well you can distinguish shades and subtle differences between an object and its surroundings, such as a curb from a sidewalk, a step from a landing, or a face in dim lighting.

Many patients with normal or near-normal visual acuity still struggle significantly with contrast sensitivity, especially those affected by macular degeneration, glaucoma, diabetic retinopathy, or cataracts. This is often why patients say things like “I can read the eye chart fine, but I still can’t see well” — visual acuity and contrast sensitivity are simply measuring two different things.

Why Contrast Sensitivity Testing Matters

Reduced contrast sensitivity can affect everyday safety and independence in ways that are easy to underestimate, including:

• Difficulty seeing steps, curbs, or changes in elevation
• Trouble driving at night or in overcast conditions
• Difficulty recognizing faces or facial expressions
• Challenges reading text on low-contrast backgrounds, such as light gray print

Because these challenges don’t always show up on a standard eye chart, contrast sensitivity testing is a key part of a comprehensive low vision evaluation. Understanding your specific contrast sensitivity helps us recommend the most effective low vision treatments and devices for your daily life, rather than relying on visual acuity alone.

How We Use These Results

Once we understand your contrast sensitivity, we can better tailor recommendations such as specific lens tints, lighting changes at home, or specialized low vision glasses designed to enhance contrast and clarity. For some patients, this insight also informs a course of low vision rehabilitation therapy, helping you adapt daily habits — like lighting placement or walking pace on stairs — around your specific visual profile.

Contrast sensitivity often changes alongside the eye diseases that cause low vision. Learn more about these conditions on our Low Vision Diseases page, or see our complete range of care on the Living With Low Vision page. If you’re new to our practice, our New Patient Center outlines exactly what to expect at your first appointment, and our Meet Our Doctor page introduces the specialist who will guide your care.