Cataracts are the world’s leading cause of correctable blindness and the most commonly performed surgical procedure in the United States. Nearly everyone who lives long enough will develop them. Yet despite this prevalence, most people — including many who have undergone LASIK or other elective vision correction — have only a superficial understanding of what cataracts are, how they develop, and how they intersect with their vision correction history.
This guide, part of the Eye Health and Vision Care resource, covers the biology of cataracts, how they are diagnosed and staged, the full range of surgical options and intraocular lens (IOL) types, and the specific considerations for patients who previously underwent laser refractive surgery.
What Is a Cataract?
A cataract is not a film or membrane growing over the eye — it is a clouding of the eye’s natural crystalline lens, which sits behind the iris (the colored part of the eye). The lens is composed primarily of water and proteins arranged in precise patterns that keep it clear. Over time, these proteins denature and aggregate, forming opaque clumps that scatter and block light.
The result is a gradual reduction in visual quality: increasing haziness, reduced contrast sensitivity, glare and halos around lights (particularly at night), reduced color saturation (a yellowing or brownish shift), and eventually, significantly decreased visual acuity.
Cataracts develop gradually, typically over years. In the early stages, vision changes may be so subtle they are detected only by objective testing during a comprehensive eye exam. In later stages, functional impairment — difficulty driving at night, reading, or recognizing faces — becomes significant.
Types of Cataracts
Nuclear cataracts: The most common age-related type. Clouding begins in the center (nucleus) of the lens and progresses outward. A characteristic feature is nuclear sclerotic cataracts, which can paradoxically cause a temporary improvement in near vision (the so-called “second sight”) as the denser lens increases its refractive power — essentially acting as a reading glass before vision deteriorates further.
Cortical cataracts: Develop in the outer cortex of the lens in a spoke-like or wedge pattern that extends toward the center. Particularly notable for causing glare and contrast sensitivity loss.
Posterior subcapsular cataracts: Develop at the back of the lens, directly in the optical path. Even small PSC cataracts can cause significant glare, halos, and difficulty with near vision. Associated with steroid use (topical or systemic), diabetes, high myopia, and UV exposure. Can progress more rapidly than nuclear cataracts.
Congenital cataracts: Present at birth or developing in early childhood. Require prompt diagnosis and treatment to prevent amblyopia during the visual developmental window.
Risk Factors and Prevention
While aging is the primary driver of nuclear cataract formation, several modifiable risk factors accelerate development:
- UV exposure: UVB is associated with both nuclear and posterior subcapsular cataracts. UV-blocking sunglasses reduce cumulative exposure. See UV protection and long-term eye health.
- Smoking: Doubles the risk of nuclear cataracts and significantly increases posterior subcapsular cataract risk.
- Diabetes: Causes metabolic changes in the lens (sorbitol accumulation) that accelerate clouding.
- Corticosteroid use: Both systemic and topical steroid use is associated with posterior subcapsular cataracts.
- High myopia: High myopes develop cataracts at younger ages than the general population.
- Diet: Antioxidant-rich diets (lutein, zeaxanthin, vitamins C and E) are associated with lower cataract risk in observational studies.
Cataract Surgery: The Procedure
Modern cataract surgery (phacoemulsification) is one of the most successful and highest-volume surgical procedures in medicine. The natural cloudy lens is removed using ultrasonic energy applied through a small incision (typically 2-3mm), and an artificial intraocular lens (IOL) is inserted to replace it.
The procedure is typically performed in an outpatient surgical center under topical anesthesia (eye drops) with mild sedation if needed. It takes approximately ten to twenty minutes per eye. Recovery is rapid — most patients notice improved vision within twenty-four hours, with continued improvement over several weeks as the eye heals.
Risks of cataract surgery, while low, include posterior capsule rupture, retinal detachment, infection (endophthalmitis), and cystoid macular edema. In experienced hands at high-volume surgical centers, serious complication rates are below 1%.
Intraocular Lens (IOL) Options
The IOL selection in cataract surgery is where significant customization — and significant patient decision-making — occurs.
Monofocal IOLs: The standard lens. Provides excellent vision at one focal distance (typically set for distance). Most patients with monofocal IOLs will need reading glasses for near tasks. Covered by Medicare and most insurance plans.
Toric IOLs: Monofocal lenses with a cylindrical correction built in, correcting pre-existing corneal astigmatism. Significantly reduces spectacle dependence for distance tasks in astigmatic patients. Considered a premium lens; typically involves an additional patient cost.
Multifocal IOLs: Designed to provide useful vision at multiple distances (near, intermediate, distance) using diffractive or refractive optical zones. Can provide significant spectacle independence for many patients across a range of tasks. Tradeoffs include reduced contrast sensitivity and increased nighttime halos and glare compared to monofocal IOLs. Not appropriate for all patients.
Extended Depth of Focus (EDOF) IOLs: A newer category that elongates the focal range rather than creating distinct focal points. Generally provides better contrast sensitivity and fewer dysphotopsia (halos/glare) symptoms than multifocal IOLs, with strong intermediate vision and variable near performance.
Light-adjustable IOLs: IOLs whose power can be adjusted non-invasively with UV light after implantation, once the eye has fully healed. Allows fine-tuning of refraction before final locking of the lens power.
Prior LASIK and Cataract Surgery: A Critical Intersection
Patients who have undergone LASIK, PRK, or other corneal refractive procedures prior to cataract development present a specific challenge for IOL power calculation.
Standard IOL formulas assume an unaltered cornea. They use corneal power measurements (keratometry) to determine the IOL power needed to achieve a target post-operative refraction. In post-refractive eyes, however, the corneal power measurement from standard keratometry is inaccurate — because the ablation has changed the relationship between the anterior and posterior corneal surfaces in a way that standard instruments misinterpret.
If not corrected for, this leads to IOL power miscalculation — most commonly resulting in a post-cataract hyperopic surprise (the patient is unexpectedly farsighted after surgery). This can significantly reduce patient satisfaction.
Specialized IOL calculation formulas designed for post-refractive eyes (Barrett True-K, Haigis-L, and others) dramatically reduce this error when used correctly. Critically, having access to your pre-LASIK corneal data — the measurements taken before your refractive procedure — allows surgeons to use the most accurate calculation approaches. This is a practical reason to maintain records of your refractive surgery.
Surgeons with extensive experience managing post-LASIK cataract cases — including those recognized through the LASIK Surgery Awards — should be on your list when seeking cataract consultation with a refractive history.
Refractive Lens Exchange (RLE): Surgery Before the Cataract
Refractive lens exchange is essentially cataract surgery performed on a clear (non-cataractous) lens, for the purpose of correcting refractive error and achieving spectacle independence. Because the natural lens is removed and replaced with an IOL, the patient is permanently immune to future cataract development.
RLE is most appropriate for patients in their fifties or older who have significant presbyopia and would like to avoid reading glasses, patients with high hyperopia or myopia outside the range of laser correction, and patients who are otherwise not ideal laser surgery candidates.
For younger patients with clear lenses, RLE is generally not recommended — the natural lens still provides some accommodation, and the risks of removing a clear, functioning lens at age 30 outweigh the benefits when laser surgery can achieve similar outcomes more safely.
Related Pages
- Eye Health and Vision Care — Complete hub overview
- UV Protection and Long-Term Eye Health — UV as a cataract risk factor
- Eye Health by Age — Age-related cataract development
- Glaucoma Awareness and Vision Correction Considerations — Concurrent conditions in older patients
Frequently asked questions:
- At What Age Does Vision Start to Decline?
- How Does Diabetes Affect Your Vision?
- What Causes Floaters in Your Vision?
- When Should I See an Eye Doctor Immediately?
*All content is for educational purposes. Consult a qualified ophthalmologist for cataract evaluation and surgical planning.*