Types of Cataract: Nuclear, Cortical, Posterior Subcapsular and Other Causes

What a cataract actually is

The natural crystalline lens focuses light and is normally clear. A cataract is loss of that clarity. The word describes an optical change, not one single disease or severity.

Small peripheral opacities may have little effect, while a smaller central or posterior opacity can create disproportionate glare. The decision to treat depends on function and eye health, not appearance alone.

Nuclear sclerotic cataract

Nuclear sclerosis develops in the central lens and is strongly associated with ageing. It often progresses gradually, causing blur, reduced contrast, colour dulling and sometimes a temporary shift toward myopia.

Some patients notice that near reading briefly improves as the lens becomes more myopic—the so-called second sight—but distance vision and overall quality later decline.

Cortical cataract

Cortical cataract forms wedge-shaped or spoke-like opacities from the outer lens cortex toward the centre. Light scattering can cause glare, halos and difficulty with headlights even before standard visual-acuity loss seems severe.

Symptoms vary with pupil size and the position of the spokes. Night complaints can therefore be more important than a single chart reading.

Posterior subcapsular cataract

Posterior subcapsular cataract sits near the back of the lens, close to the visual axis. It may affect reading, bright-light vision and glare more quickly than some nuclear cataracts.

It can be associated with steroid exposure, diabetes, inflammation, high myopia, trauma or previous eye procedures, although not every case has an obvious cause.

Congenital, traumatic and secondary cataracts

Congenital or developmental cataracts may be present in infancy or appear in childhood and can threaten visual development. Traumatic cataracts may follow blunt or penetrating injury and can be accompanied by zonular, iris or retinal damage.

Secondary cataracts can be linked to diabetes, uveitis, radiation, medications or previous eye surgery. Management must address the rest of the eye, not only remove the cloudy lens.

• Age-related: nuclear, cortical or posterior subcapsular
• Congenital or developmental
• Traumatic
• Metabolic, inflammatory, medication-related or radiation-related

Why the type matters—but does not decide surgery alone

The pattern helps explain symptoms, likely progression and associated conditions. Yet surgery is generally considered when cataract interferes with useful activities or prevents examination or treatment of the back of the eye.

A dilated examination, refraction, ocular-surface assessment, macular evaluation and sometimes OCT or ultrasound help estimate how much improvement cataract surgery can reasonably provide.