What Is Nuclear Sclerosis?

Hardening or clouding of the center of the eye

Table of Contents
View All
Table of Contents

Nuclear sclerosis is a primarily age-related condition in which the nucleus, or central part of the lens of your eye, hardens or gets cloudy. Since this part of your eye receives light, nuclear sclerosis can greatly impact your vision.

The condition is called nuclear sclerotic (NS) cataracts when it progresses to the point that it's severe. You and others may notice visible changes to the eye at this stage. Blindness can occur unless nuclear sclerosis is treated.

This article reviews nuclear sclerosis and nuclear cataract stages, their causes and risk factors, and how they're diagnosed and treated.

Nuclear Sclerosis Symptoms

nuclear sclerosis symptoms

Verywell / Emily Roberts

Early on, symptoms of nuclear sclerosis can be subtle. It may take a long time for you to notice them.

They can include:

  • Worsening vision (especially distance) that doesn't improve with glasses or contacts
  • Needing frequent updates to your lens prescription
  • Blurry, unfocused vision ("clouding")
  • Colors and shadows appearing less vivid
  • "Haloes" or rings around light sources; seeing a glare
  • Trouble seeing at night, especially when driving

Some people with nuclear sclerosis see a temporary improvement in their vision. This is sometimes called second sight. It can make you think your eyes have gotten better, but the slow decline inevitably continues.

Nuclear Cataract Symptoms

With nuclear cataracts, the center of the eye's lens becomes thick and discolored. Symptoms and signs of nuclear cataracts include:

  • Noticeable changes in the appearance of the affected eye(s), including cloudiness, yellow, or browning
  • Blurred and cloudy vision
  • Haloes around lights
  • Washed-out colors

At first, you may get a cataract in just one eye. Over time, you'll likely develop one in the other eye, too. Vision may improve, only to decline again.

Nuclear cataracts can be classified as either immature or mature, depending on how severe the clouding is. In severe cases, untreated nuclear cataracts can cause blindness.

Cataracts are the leading cause of blindness both in the United States and around the world.

Causes of Nuclear Sclerosis

Nuclear sclerosis is caused by proteins in your eye lens that naturally break down over time. They clump together and cause hardening that impedes light from passing through the center of the lens to the retina.

The retina processes light and transfers signals that allow your brain to register images. Less light going through the center of the lens due to nuclear sclerosis means less "information" for the retina to translate. That, in turn, equates to vision issues.

As you age, your nuclear sclerosis will eventually develop into an NS cataract. In addition to aging, cataracts can be caused by trauma or disease.

Age-related cataracts are extremely common and nuclear sclerotic cataracts are the most common kind. Other types of cataracts result from changes to different parts of the lens.

To differentiate them from other types of cataracts, NS cataracts caused by age are sometimes referred to as nuclear senile cataracts.

Risk Factors

Age is the main risk factor for nuclear sclerotic cataracts. Other risk factors include:

  • Smoking or other tobacco use
  • Heavy alcohol use
  • Steroid drugs
  • Eye trauma or diseases
  • Excessive exposure to UV light (sunlight) or radiation
  • Other health conditions including diabetes, high blood pressure, chronic kidney disease, autoimmune disease, nutritional deficiency, and obesity
  • A relative who had cataracts early in life

Diagnosis

If you have symptoms that could point to nuclear sclerosis, see an eye doctor (ophthalmologist).

Nuclear cataracts are typically easy to diagnose. That's especially true if they've changed how the lens looks.

Healthcare providers use special eye drops to dilate (widen) your pupil. Then they look inside your eye with a handheld instrument called an ophthalmoscope and a slit-lamp microscope. If you have nuclear sclerosis, the healthcare provider will see abnormalities in the lens's nucleus.

They'll also perform refraction (vision prescription) and acuity (eye chart) tests on both eyes to check your vision's clarity and sharpness.

Sometimes an eye health professional can see early changes before you have noticeable symptoms. This reinforces the importance of routine eye exams. Early diagnosis means early treatment, and that may prevent or delay serious vision loss—including blindness.

Treating Nuclear Sclerosis

Early on, glasses or contacts may be all you need to help manage symptoms of nuclear sclerosis. You may also find it helpful to:

  • Use brighter light bulbs
  • Wear anti-glare sunglasses
  • Use a magnifying lens for reading and close-up activities

Eventually, healthcare providers may be able to treat nuclear sclerosis with eye drops. Treating it in the early stages may prevent nuclear cataracts from forming. For now, though, this treatment is experimental.

Cataract Surgery

Healthcare providers generally suggest surgery when the above options aren't sufficient and nuclear cataracts significantly impact your life (e.g., make you unable to drive).

Cataract surgery involves removing the cloudy lens and replacing it with a clear synthetic one that is created especially for your eye. It is considered safe for most people.

If you have nuclear sclerotic cataracts in both eyes, they will probably be removed during separate procedures done about a week apart. Most people fully recover in about eight weeks.

Cataract surgery has a 97% or higher success rate.

Summary

Nuclear sclerotic cataracts impact the center of your eye's lens. With age (or sometimes, eye disease), the lens thickens, becomes cloudy, and impairs your vision.

Symptoms include blurry vision (especially at night), frequent updates to your corrective lenses, and colors appearing less vivid.

Healthcare providers diagnose nuclear sclerosis with a dilated eye exam. Treatment includes corrective lenses or, later on, surgery to replace the affected lens.

A Word From Verywell

With treatment, nuclear sclerosis and nuclear sclerotic cataracts rarely cause blindness. Getting regular eye exams is key to early diagnosis and treatment, which can help preserve your vision.

As you get older, don't skip these exams and be sure to tell your healthcare provider about any vision changes.

Frequently Asked Questions

  • Is nuclear sclerosis normal?

    Nuclear sclerosis is expected with age. In the United States, more than half of all people have had a cataract or cataract surgery by age 80, with nuclear sclerosis being the most common cause.

  • What are nuclear sclerosis stages?

    Each stage of nuclear sclerosis is given a grade of 1 through 6. These define its progression to nuclear cataracts, with each increasing number indicating a greater level of severity.

  • How fast do nuclear cataracts grow?

    Nuclear cataracts are slow to develop. It may be several years before you realize you have nuclear sclerosis.

  • Can nuclear sclerosis be cured?

    Nuclear sclerosis can be treated, but not cured. Corrective lenses and lifestyle changes help people adapt to changing vision. With advanced nuclear cataracts, surgery is an option.

12 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. University of Michigan Health System, Kellogg Eye Center. Nuclear cataract.

  2. American Optometric Association. Cataract.

  3. Frampton G, Harris P, Cooper K, et al. Chapter 1: Background. In: The clinical effectiveness and cost-effectiveness of second-eye cataract surgery: a systematic review and economic evaluationSouthampton (UK): NIHR Journals Library.

  4. U.S. Centers for Disease Control and Prevention. Common eye disorders and diseases.

  5. Yanoff M, Sassani JW. Chapter 10 - Lens. In: Ocular pathologyElsevier.

  6. National Institutes of Health, National Eye Institute. Cataracts.

  7. Ang MJ, Afshari NA. Cataract and systemic disease: A reviewClin Exp Ophthalmol. 2021;49(2):118-127. doi:10.1111/ceo.13892

  8. American Academy of Ophthalmology: EyeSmart. What are cataracts?

  9. Sanchez RF, Everson R, Hedley J, et al. Rabbits with naturally occurring cataracts referred for phacoemulsification and intraocular lens implantation: a preliminary study of 12 cases. Vet Ophthalmol. 2018;21(4):399-412. doi:10.1111/vop.12525

  10. Thompson J, Lakhani N. Cataracts. Prim Care. 2015;42(3):409-23. doi:10.1016/j.pop.2015.05.012

  11. American Academy of Ophthalmology. Cataract.

  12. Johns Hopkins Medicine. Cataracts.

By Abby Norman
Abby Norman is a freelance science writer and medical editor. She is also the author of "Ask Me About My Uterus: A Quest to Make Doctors Believe in Women's Pain."