R R

What Percentage of Color Blindness Cases Are Passed from Mother to Son?

A cataract is a clouding of the eye's natural crystalline lens, typically caused by the oxidative stress and protein clumping that occurs with age. Cataracts are classified based on their location within the lens architecture. The lens is structured much like an onion; the "nuclear" portion is the hardened center, while the "cortical" portion consists of the outer layers surrounding that center. While most patients eventually develop a combination of both, the primary type of opacity determines the specific visual symptoms and the rate at which the vision declines.

Link to This Resource Page

Provide a valuable resource to your clients or customers by linking to this resource page. Just place the following link on your website.

To display this...

What Percentage of Color Blindness Cases Are Passed from Mother to Son?

A cataract is a clouding of the eye's natural crystalline lens, typically caused by the oxidative stress and protein clumping that occurs with age. Cataracts are classified based on their location within the lens architecture. The lens is structured much like an onion; the "nuclear" portion is the hardened center, while the "cortical" portion consists of the outer layers surrounding that center. While most patients eventually develop a combination of both, the primary type of opacity determines the specific visual symptoms and the rate at which the vision declines.

read more about percentage of cortical versus nuclear sclerotic cataracts ...

Copy this HTML:

Copy HTML Copied!

Distribution Statistics and Prevalence

In the population of adults over age 60, Nuclear Sclerotic Cataracts (NSC) are the most prevalent, accounting for approximately 60 percent to 70 percent of all diagnosed cases. Cortical Cataracts (CC) are the second most common, representing roughly 20 percent to 25 percent of the cataract population. The remaining percentage is attributed to Posterior Subcapsular Cataracts (PSC), which are less common but often more visually significant at an earlier age. In 2026, data suggests that roughly 15 percent of patients present with "mixed" cataracts where both nuclear and cortical changes are equally contributing to vision loss.

Nuclear Sclerosis: The "Second Sight" Phenomenon

Nuclear sclerotic cataracts involve a gradual hardening and yellowing (brunescence) of the lens center. This process increases the refractive power of the lens, often creating a "myopic shift." This can lead to a temporary phenomenon known as "second sight," where a farsighted elderly patient suddenly finds they can read without glasses again. However, this is eventually overtaken by a generalized "washout" of colors and a significant decrease in distance clarity. In 2026, NSC is the primary reason for the "faded" or "sepia-toned" vision reported by seniors.

Cortical Cataracts: The "Spoke-Like" Opacity

Cortical cataracts begin as white, wedge-like opacities (called cortical spokes) that start at the periphery of the lens and work their way toward the center. Because they start at the edges, they often have little effect on vision in the early stages. However, as the spokes reach the visual axis, they scatter light in a very specific way. Patients with cortical cataracts frequently report "starbursts" or "glare" around headlights while driving at night. 2026 clinical data indicates that cortical cataracts are more highly associated with UV exposure and metabolic conditions like diabetes than nuclear sclerosis.

Symptom Comparison and Progression Rates

The progression of these two types differs significantly. Nuclear sclerotic cataracts are typically very slow-growing, often taking a decade to move from "trace" to "surgical" levels. Cortical cataracts can be more unpredictable, sometimes progressing rapidly if a person experiences significant fluctuations in blood sugar or high levels of oxidative stress. In the 2026 surgical environment, the type of cataract often dictates the surgeon's choice of phacoemulsification settings, as nuclear cataracts require more ultrasonic energy to "break up" the hardened center compared to the softer cortical material.

FAQs on Cataract Types

Can I have both at the same time?

Yes. It is very common to have a "Grade 2 Nuclear Sclerosis with Trace Cortical Spokes." When both are present, your vision may suffer from both a loss of contrast and increased glare at night. Your surgeon will treat both simultaneously during a single cataract procedure by removing the entire lens.

Which type is harder to remove?

Generally, a very "dense" or "brunescent" nuclear cataract is more challenging because the lens has become extremely hard, requiring more energy to remove. Cortical cataracts are usually softer but can sometimes be "sticky," requiring more meticulous cleaning of the lens capsule during surgery.

Does the type of cataract change which IOL I should choose?

Not necessarily. The choice of an Intraocular Lens (IOL) such as a multifocal or toric lens is based more on your lifestyle and your eye's corneal shape rather than the type of cataract you had. However, if you have significant glare from cortical spokes, you will find the relief after surgery to be particularly dramatic.

When to Discuss Cataract Types with Your Surgeon

If you find that you are struggling with night driving specifically, or if you feel like you are constantly cleaning your glasses because the world looks "yellow," you should ask your doctor which type of lens change they see. In 2026, we no longer wait for cataracts to "ripen." Instead, we use "Functional Vision Assessments" to determine if your specific type of cataract, whether nuclear or cortical, is interfering with your safety and quality of life. Modern surgery can replace either type with a clear, permanent implant in less than 15 minutes.

References

https://www.nei.nih.gov/learn-about-eye-health/eye-conditions-and-diseases/color-blindness/causes-color-blindness
https://www.aao.org/eye-health/diseases/color-blindness-inheritance
https://pubmed.ncbi.nlm.nih.gov/31355431/