Color Blind Lens in Bangladesh: Can Color Blindness Be Corrected?

Of all the questions patients bring to me about vision, questions about color blindness carry a particular weight. Because unlike asking about glasses or laser surgery — where the solution is relatively straightforward — color blindness sits in a different category. It is usually present from birth. It is inherited. It cannot be cured. And for years, patients in Bangladesh had almost nowhere to turn for honest, medically grounded information about whether anything could be done.

That is changing.

Color blind lenses — both spectacle lenses and contact lenses with specialised optical filters — are now available in Bangladesh and offer real, measurable benefit for many patients with color vision deficiency. But I also want to be honest with you about what they can and cannot do. You deserve a clear answer, not a sales pitch.

This article covers exactly what color blindness is, how color blind lenses work, who they help and who they do not, what you can realistically expect, and how to access assessment and prescription in Bangladesh.

What is Color Blindness? — The Correct Term is Color Vision Deficiency

Let me start with the science, because understanding it changes how you think about the available solutions.

A normal human eye sees three primary colors: red, green and blue. All other colors are the result of mixtures of these three. When a person has Color Vision Deficiency, one or more of the three primary colors is not detected correctly — reducing the number of color shades visible and slowing comprehension and reaction time. Source: Medical News Today

The photoreceptor cells responsible for color detection are called cones, and there are three types — each sensitive to a different range of wavelengths. In a color vision deficient eye, one or more cone types either function abnormally or overlap excessively in their sensitivity range with a neighbouring cone type, causing colors that should be distinct to appear similar or identical.

Color vision deficiency (CVD) is the clinically precise term. “Color blindness” is the common name — and it is slightly misleading, because the vast majority of people with CVD are not completely blind to color. They see color — just less of it, or less accurately than people with normal trichromatic vision.

Types of color vision deficiency:

How common is it in Bangladesh?

Color vision deficiency affects approximately 8% of males and 0.5% of females of all ethnicities globally — making it one of the most common inherited conditions affecting vision. In a country of 170 million people, this means an estimated 6–7 million Bangladeshis live with some form of CVD. The vast majority are undiagnosed — many simply adapting without ever knowing the clinical name for what they experience.

How Color Blind Lenses Work — The Science Explained Honestly

This is the section I want to be most careful about — because there is a great deal of marketing language around color blind lenses that can give patients unrealistic expectations.

Color blind glasses use tinted filters to shift how reds and greens appear to people with red-green color blindness. They do not cure color blindness. Peer-reviewed studies show results that vary by person, deficiency type, and the test being used.

Here is the honest mechanism:

The most common form of red-green color blindness involves an excessive overlap between the sensitivity curves of the red and green cone photoreceptors. Because these two types of cones respond to too similar a range of wavelengths, the brain receives ambiguous signals — red and green look similar because they both stimulate both types of cones almost equally.

Color blind lenses work by blocking narrow bands of light — mostly in the 530 to 560 nm range where red and green cone responses overlap most. Cutting that overlap is meant to increase the contrast between red and green signals, so colors that normally look similar become easier to tell apart. This is contrast enhancement, not correction — the lenses do not repair the underlying cone cells. They change the light that reaches the eye so existing cones receive a clearer, less ambiguous signal.

After wearing the lenses for 90–120 seconds, the eyes naturally adjust through a process called chromatic adaptation — white appears as white again, while the enhanced color contrast is maintained.

What this means in practice:

• Colors appear more vibrant, more distinct, and more saturated
• Red-green confusion is reduced — many patients can distinguish colors they previously could not
• Passing standardised color vision tests (Ishihara, Farnsworth D-15) becomes possible for some patients with prescribed, customised lenses
• The glasses do not give a colorblind person normal color vision — but they can help some colors look more vibrant or noticeable, and significantly improve daily color discrimination Eye Institute
• The effect is only present while wearing the lenses — vision returns to its baseline state when removed

Types of Color Blind Lenses Available in Bangladesh

There are two main formats — each with different advantages:

Spectacle Lenses (Glasses)
Tinted filter lenses mounted in spectacle frames. Available in indoor and outdoor versions — outdoor lenses are darker, tuned for bright sunlight where red-green contrast improvement is most noticeable. The most accessible format and suitable for patients of all ages including children.

Contact Lenses for Color Blindness
Some companies make contact lenses with a red filter, worn in one eye, to better distinguish between colors as needed. Customised color corrective contact lenses — prescribed after a detailed color vision evaluation — offer a more discreet option for patients who prefer not to wear spectacles. They are generally not visible to others and can be worn by anyone who has previously worn contact lenses.

The key distinction between generic off-the-shelf lenses and prescription color corrective lenses is critical. Generic lenses apply the same filter to all wearers regardless of their specific type or degree of deficiency. Customised lenses are prescribed after a full color vision examination — matched precisely to your deficiency type, severity, and the specific wavelength adjustment needed for your individual cone sensitivity profile.

“In my practice, when patients ask about color blind lenses, the most important thing I tell them is this: a generic filter from the internet and a properly prescribed, customised color vision lens are not the same thing. One is a product. The other is a medical solution. Get assessed properly, and you will know which option genuinely helps your specific type of color vision deficiency.”
— Dr. Ashraful Huq

Who Does a Color Blind Lens Actually Help?

Approximately 80% of people with red-green color blindness will see an expanded range of visible colors and distinguish shades more accurately when using appropriately prescribed color filter lenses. However, results vary significantly by:

Most likely to benefit:

• Patients with deuteranomaly or protanomaly — the anomalous trichromats (reduced but not absent cone function). These patients have all three cone types but with shifted sensitivity, making them the ideal candidates for wavelength filtering
• Patients who need to pass standardised color vision tests — Ishihara colour plates, Farnsworth D-15, Rabin Cone Contrast Test — for professional licensing (pilots, military, police, electrical workers, medical professionals)
• Patients experiencing practical daily difficulties — choosing clothing colours, distinguishing traffic lights in certain conditions, reading colour-coded maps or graphs, distinguishing ripe from unripe fruit

Less likely to benefit:

• Patients with deuteranopia or protanopia — the dichromats, who lack an entire cone type rather than having a shifted one. Filtering helps less when a cone type is entirely absent
• Patients with tritanopia (blue-yellow deficiency) — most colour blind lenses are specifically designed for red-green deficiency
• Patients with achromatopsia — complete absence of cone function; lenses cannot create cone sensitivity that does not exist
• Patients seeking permanent correction — the effect ceases when the lenses are removed

Color Blindness and Career Impact in Bangladesh — Why This Matters

This is a dimension of color vision deficiency that rarely gets discussed in medical articles — but it matters enormously to my patients in Bangladesh.

Many professions in Bangladesh require passing a formal color vision test as a condition of employment or licensing. These include:

• Bangladesh Navy, Army, and Air Force — color vision standards strictly enforced for active duty roles
• Civil Aviation — pilots and air traffic controllers require full color vision or correctable CVD
• Bangladesh Police Service — color vision testing at recruitment
• Electrical and electronics engineering — wire colour identification is safety-critical
• Medical and nursing professions — certain specialties require colour discrimination
• Railway and transport — signal colour identification is essential
• Graphic design and printing industries — colour accuracy is a core professional requirement

For patients in these categories, the goal is not just seeing more colors — it is passing the Ishihara or Farnsworth D-15 test that stands between them and their career. Customised prescriptive color corrective contact lenses, properly assessed and fitted, can make this possible for many patients with anomalous trichromacy.

I have seen patients in my clinic who had been turned away from their chosen career because of CVD — not knowing that a proper assessment and customised lens could have changed that outcome. This is why I believe awareness of color blind lens options in Bangladesh is so important.

What the Assessment Involves — Getting a Proper Color Vision Evaluation

A thorough color vision assessment at a specialist eye clinic involves several components:

1. History Taking
Understanding when the color vision difficulty was first noticed, whether it is congenital (present since birth) or acquired (developed over time), family history of CVD, and the specific situations where color confusion causes difficulty.

2. Ishihara Colour Plate Test
The most widely used screening test — a series of plates with numbers or patterns embedded in coloured dots. Identifies red-green deficiency quickly. Not suitable for precisely grading severity or type.

3. Farnsworth D-15 Panel Test
Fifteen coloured discs that must be arranged in colour order. Identifies the axis and severity of colour deficiency more precisely than Ishihara.

4. Rabin Cone Contrast Test (RCCT)
A more sensitive, computerised test that quantifies the specific degree of red, green, and blue cone sensitivity. Particularly relevant for professional color vision testing.

5. Anomaloscopy
The gold standard for precisely classifying the type and severity of red-green deficiency — distinguishing anomalous trichromacy from dichromacy with precision. Guides the exact wavelength filter prescription.

6. Full Eye Examination
It is important to rule out acquired causes of color vision change — cataracts, macular disease, glaucoma, optic neuritis, or medication side effects — particularly in adults whose color vision has changed over time. Color vision changes that come on later in life can point to eye disease, cataracts, neurologic problems, or medication side effects, and those need a clinical workup rather than a tinted lens.

Can Color Blindness Be Permanently Cured?

I want to answer this directly, because patients often come to me having read about gene therapy and hope it may be available in Bangladesh now.

To date, there is no therapeutic solution that can restore typical color vision. There have been considerable developments concerning technological interventions — hardware-based aids including tinted glasses and filters, and software-based methods for enhancing colour perception in digital environments.

Gene therapy for color blindness has shown promising early results in animal studies — and limited human trials have begun in the US for certain rare forms of achromatopsia. However, as of 2026, gene therapy for common red-green color blindness is not clinically available anywhere in the world, including Bangladesh. It remains a research-stage intervention.

What is available and proven:

• Color blind spectacle and contact lenses — practical, accessible, beneficial for the majority of red-green CVD patients
• Digital tools and apps — smartphone apps that identify and name colors, colorblind-friendly screen modes built into modern devices
• Environmental adaptation strategies — labelling systems, colour-coded organisation tools

What is not yet available:

• A permanent medical cure for inherited color vision deficiency
• Gene therapy outside of clinical trial settings
• Any eye drop, supplement, or exercise that restores cone function

Frequently Asked Questions — Color Blind Lens Bangladesh

Can color blindness be corrected in Bangladesh?

Color blindness cannot be permanently cured, but color blind lenses — specially filtered spectacle or contact lenses — can significantly improve colour discrimination for most patients with red-green colour vision deficiency. Customised prescription colour corrective lenses are available at specialist eye clinics in Bangladesh.

What is a color blind lens?

A color blind lens is a specially filtered optical lens — in spectacle or contact lens form — that blocks specific wavelengths of light where red and green cone sensitivities overlap. This increases contrast between red and green signals reaching the eye, helping the brain distinguish colours that previously appeared identical or similar.

Who benefits most from color blind lenses?

Patients with anomalous trichromacy — deuteranomaly or protanomaly — benefit most, as they have all three cone types but with shifted sensitivity. Patients needing to pass professional colour vision tests (Ishihara, Farnsworth D-15) for careers in aviation, military, medicine, or engineering are strong candidates for customised colour corrective lenses.

Do color blind lenses work permanently?

No. Colour blind lenses improve colour perception only while being worn. When the lenses are removed, vision returns to its baseline state. There is currently no permanent cure for inherited colour vision deficiency available anywhere in the world.

Can children use color blind lenses?

Yes. Colour blind lenses are safe for children from school age onwards. Early diagnosis and lens fitting can significantly improve a child’s educational experience — particularly with colour-coded learning materials — and avoid career limitation later. A full colour vision assessment at a specialist clinic is recommended.

How do I get a color blind lens in Bangladesh?

Visit a specialist ophthalmologist or optometrist for a full colour vision evaluation — including Ishihara plate testing, Farnsworth D-15 panel test, and ideally anomaloscopy for precise deficiency grading. Based on your type and severity, a customised colour corrective lens can be prescribed. Dr. Ashraful Huq performs full colour vision assessments at Bangladesh Eye Hospital (BEH), Dhaka.

Can color blind lenses help me pass the Ishihara test?

Customised prescription colour corrective contact lenses — properly assessed and fitted for your specific deficiency — can enable many patients with anomalous trichromacy to pass standardised colour vision tests including the Ishihara, Farnsworth D-15, and Rabin Cone Contrast Test. Generic off-the-shelf lenses are less reliable for this purpose.