What Is Colour Deficiency? Types and Causes Explained

Colour plays a key role in how we interact with the world - from recognizing traffic signals to appreciating vibrant art. But for many people, distinguishing between certain colours isn’t always easy. This condition, known as colour deficiency (or colour vision deficiency), affects how the eyes and brain interpret colour information. At Nvision Eyecare, our eye doctors in Auckland provide comprehensive assessments and support for patients with colour vision challenges. Here’s what you need to know about this common condition.

What Is Colour Deficiency?

Colour deficiency occurs when the eyes are unable to perceive colours in the typical way. It usually affects the ability to distinguish between shades of red, green, or blue. Many people refer to it as “colour blindness,” but complete colour blindness - seeing only in shades of grey - is extremely rare. Most people with colour deficiency can still see colour - just not as accurately or clearly.

Types of Colour Deficiency

There are several types of colour vision deficiencies, each related to how the colour-sensing cells in the retina (called cones) function. The most common form is red-green colour deficiency, which involves difficulty distinguishing between shades of red and green. Within this category, there are two primary variations: protanomaly or protanopia, where there is reduced or missing sensitivity to red light, and deuteranomaly or deuteranopia, where sensitivity to green light is reduced or absent.

A less common type is blue-yellow colour deficiency, which affects the ability to differentiate between blues and yellows. This form includes tritanomaly or tritanopia - conditions where there is reduced or missing sensitivity to blue light.

What Causes Colour Deficiency?

Colour deficiency can have several origins:

• Genetics: Passed down from parents and present from birth. Red-green deficiency is often inherited.

• Age-related changes: The eyes can become less sensitive to colour over time.

• Medical conditions: Such as glaucoma, macular degeneration, or diabetes.

• Medications: Certain prescriptions may affect colour vision.

• Eye injury or disease: Damage to the retina or optic nerve can impact colour perception.

Early diagnosis can have a positive impact on learning, development, and daily activities—especially for children.

How Is Colour Deficiency Diagnosed and Treated?

A colour vision test is the most reliable way to determine the type and extent of colour deficiency. At Nvision Eyecare, we use trusted testing methods as part of a comprehensive eye exam to better understand each patient’s visual needs.

While there is currently no cure for inherited colour deficiency, many solutions can help enhance colour perception and confidence in daily tasks:

• Special tinted glasses designed to improve contrast between colours

• Tinted contact lenses that may enhance visual distinction for certain colour types

• Adaptive tools and strategies to support reading, safety, and learning environments

Our colour vision specialists in Auckland can recommend the most appropriate options based on your individual assessment.

Get Personalized Colour Vision Solutions at Nvision Eyecare

Colour deficiency is more common than many realize, and understanding it is the first step toward improving visual comfort and function. Whether you’ve noticed colour-mixing difficulties in yourself or your child, a thorough colour vision test can provide clarity and guidance.

If you are experiencing colour deficiency, schedule a consultation at Nvision Eyecare for tailored solutions. Visit our office in Auckland, or call 09-884-0034 to book an appointment today.