MyEClinic
MyEClinic
Health Dictionary Find a Doctor

Cataract


Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1], Associate Editor-In-Chief: Joseph Nasr, M.D.[2]

For patient information click here

Template:DiseaseDisorder infobox

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [3]; Kenneth J. Hoffer, M.D. [4], Clinical Professor of Ophthalmology, UCLA, St. Mary’s Eye Center Associate Editor(s)-in-Chief: Rohan Bir Singh, M.B.B.S.[5]

Overview

Overview

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1], Associate Editor-In-Chief: Joseph Nasr, M.D.[2]

A cataract is an opacification of the natural intraocular crystalline lens, or its capsule, which normally transmits and focuses light onto the retina in the posterior part of the eye. This opacification results in a progressive decrease in visual acuity and visual function and may lead to complete vision loss if left untreated. In the early stages of age-related cataract, changes in the refractive index of the crystalline lens may increase lens power, resulting in a myopic shift, while gradual yellowing and clouding of the lens can impair color perception, particularly of blue hues.

Cataracts typically progress slowly but are potentially blinding. In advanced cases, liquefaction of the lens cortex may result in a Morgagnian cataract, which can provoke severe intraocular inflammation if the lens capsule ruptures. Untreated cataracts may also lead to complications such as phacomorphic glaucoma. In very advanced disease, zonular weakness may result in anterior or posterior dislocation of the lens. Historically, spontaneous posterior dislocation of the lens occasionally restored limited light perception in bilaterally affected individuals.

Cataracts are the leading cause of blindness worldwide and the leading cause of preventable blindness.[1] Globally, cataracts accounted for approximately 15 million cases of blindness and 79 million cases of moderate to severe visual impairment among individuals aged 50 years or older in 2020.[2] In the United States, age-related lenticular changes have been reported in approximately 42% of individuals aged 52 to 64 years,[3] 60% of those aged 65 to 74 years,[4] and 91% of individuals aged 75 to 85 years.[3]

At present, there are no scientifically proven interventions to prevent cataract formation or progression. Although ultraviolet light exposure has been implicated as a risk factor, and the use of ultraviolet-protective sunglasses is sometimes suggested as a protective measure, definitive benefit has not been established.[5][6] Antioxidant supplementation, including vitamins C and E, has been proposed but has not been proven effective.

Cataract surgery is the only effective and approved treatment for cataracts. The procedure involves removal of the opacified crystalline lens, which develops due to metabolic changes within lens fibers over time, followed by implantation of an artificial intraocular lens (IOL). Cataract surgery is generally performed by an ophthalmologist in an ambulatory surgical center or hospital setting using local anesthesia, including topical, peribulbar, or retrobulbar techniques. More than 90% of cataract operations successfully restore useful vision, with a low complication rate,[7] and modern small-incision phacoemulsification with rapid postoperative recovery has become the standard of care worldwide. In the United States, cataract extraction with intraocular lens implantation is one of the most commonly performed surgical procedures, with approximately 3 million surgeries performed annually.

Visual acuity may not improve to 20/20 following cataract surgery if other ocular conditions, such as age-related macular degeneration, are present. In many cases, ophthalmologists can, but not always, identify these limiting factors preoperatively.

The term cataract is derived from the Latin cataracta, meaning “waterfall,” and the Greek kataraktēs or katarrhaktēs, from katarassein, meaning “to dash down.” The term likely originated from the resemblance of mature lens opacities to rapidly running white water, although in Latin it also referred to a “portcullis,” suggesting obstruction as an alternative etymologic origin.

References

  1. ↑ https://web.emmes.com/study/areds/mopfiles/chp2_mop.pdf
  2. ↑ GBD 2019 Blindness and Vision Impairment Collaborators; Vision Loss Expert Group of the Global Burden of Disease Study. Causes of blindness and vision impairment in 2020 and trends over 30 years, and prevalence of avoidable blindness in relation to VISION 2020: the Right to Sight: an analysis for the Global Burden of Disease Study. Lancet Glob Health. 2021;9(2):e144-e160. doi:10.1016/S2214-109X(20)30489-7
  3. ↑ 3.0 3.1 Sperduto RD, Seigel D. Sperduto RD, Seigel D. “Senile lens and senile macular changes in a population-based sample.” Am J Ophthalmol. 1980 Jul;90(1):86-91. PMID 7395962.
  4. ↑ Kahn HA, Leibowitz HM, Ganley JP, Kini MM, Colton T, Nickerson RS, Dawber TR. “The Framingham Eye Study. I. Outline and major prevalence findings.” Am J Epidemiol. 1977 Jul;106(1):17-32. PMID 879158.
  5. ↑ Epidemiology. 2003 Nov;14(6):707-12. Sun exposure as a risk factor for nuclear cataract
  6. ↑ http://www.nei.nih.gov/nehep/pdf/NEHEP_5_year_agenda_2006.pdf p.37 quoting Javitt, J. C., F. Wang, and S. K. West. “Blindness Due to Cataract: Epidemiology and Prevention.” Annual Review of Public Health 17 (1996): 159-77.
  7. ↑ University of Illinois Eye Center.“Cataracts.” Retrieved August 18, 2006.

Template:WS Template:WH

Historical Perspective

Historical Perspective

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Rohan Bir Singh, M.B.B.S.[2] , Joseph Nasr, M.D.[3]

The earliest documented references to cataract surgery are found in Sanskrit medical manuscripts dating to the 5th century BC. These texts describe the work of Sushruta, an ancient Indian physician who developed specialized surgical instruments and performed some of the earliest known eye surgeries, including extracapsular techniques for cataract treatment.[1][2] The Susrutasamhita describes removal of cataracts using sharply pointed instruments, representing some of the first recorded ophthalmic surgical procedures.

In the Western world, bronze instruments that may have been used for cataract surgery have been identified in archaeological excavations in Babylonia, Greece, and Egypt. Although cataracts are not explicitly described in surviving ancient Egyptian medical texts, a condition resembling cataract has been referenced in the Ebers Papyrus. The earliest detailed Western medical descriptions of cataract and its treatment appear in De Medicina (circa 29 AD), written by the Roman encyclopedist Aulus Cornelius Celsus, who described couching as a surgical intervention for cataract.

Couching involved using a thin needle or similar instrument to displace the opaque lens posteriorly into the vitreous cavity. Although this technique occasionally restored limited light perception, it was associated with poor visual outcomes and high complication rates. Nevertheless, couching persisted from antiquity through the Middle Ages and remained the dominant method of cataract treatment for centuries.

In ancient Greek medicine, the crystalline lens was believed to be the structure responsible for vision. This belief contributed to the development of the emanation theory of vision, which proposed that visual “spirits” traveled from the brain through hollow optic nerves to interact with rays from the external world at the lens. Around 30 AD, Celsus depicted the lens at the center of the globe with an anterior empty space known as the locus vacuus. This anatomical model persisted through the Middle Ages and into the Renaissance, as illustrated by the Belgian anatomist Andreas Vesalius in 1543.

The first accurate depiction of the crystalline lens position was published by the Italian anatomist Fabricius ab Aquapendente in 1600. Swiss physician Felix Plater later challenged prevailing theories of vision by proposing that the retina, rather than the lens, was the structure responsible for sight.

A major transition in cataract treatment occurred in 1748 when Jacques Daviel introduced true cataract extraction, in which the opaque lens was removed from the eye rather than displaced. This marked the beginning of modern cataract surgery. Further advances occurred in the 20th century, including the introduction of intraocular lens implantation by Harold Ridley in the 1940s, which significantly improved postoperative visual rehabilitation (Apple et al., 2000).

Modern cataract surgery continued to evolve with the introduction of phacoemulsification by Charles Kelman in 1967. This technique uses ultrasonic energy to emulsify the lens nucleus, allowing cataract removal through a small incision and reducing the need for prolonged hospitalization. These innovations established extracapsular cataract extraction and phacoemulsification with intraocular lens implantation as the foundation of contemporary cataract surgery (Apple et al., 2000).

By the late 20th and early 21st centuries, cataract surgery had become one of the most commonly performed surgical procedures worldwide. Surveys of members of the American Society of Cataract and Refractive Surgery reported approximately 2.85 million cataract procedures performed in the United States in 2004 and 2.79 million in 2005.[3] In India, modern cataract surgery with intraocular lens implantation has largely replaced older techniques, particularly through government and non-governmental organization–sponsored eye surgical camps.

References

  1. ↑ Susruta article
  2. ↑ Susruta pubmed reference article
  3. ↑ American Academy of Ophthalmology reference

Template:WS Template:WH

Classification

Classification

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Rohan Bir Singh, M.B.B.S.[2]

Overview

Cataracts are classified based on the anatomic location of lens opacification, as determined by slit-lamp examination. The three primary age-related cataract subtypes are nuclear cataract, cortical cataract, and posterior subcapsular cataract.[1]

Nuclear cataracts involve opacification and increased density of the central lens nucleus and are the most common type associated with aging. These cataracts may be associated with changes in refractive status, including myopic shift, prior to progressive visual decline.[1]

Cortical cataracts arise from the lens cortex and are characterized by spoke-like opacities extending from the peripheral lens toward the center. These cataracts commonly cause glare and reduced contrast sensitivity.[2]

Posterior subcapsular cataracts occur near the posterior lens capsule and disproportionately impair near vision and reading ability. They are more likely to cause glare and are often symptomatic earlier in their course than other cataract subtypes.[1]

Classification

The classification of cataracts is based on four different criteria.

  1. Morphology,
  2. Age of Onset
  3. Maturity
  4. Etiology
  5. Location of opacity
Sub-types
Morphology
  • Capsular
  • Subcapsular
  • Nuclear
  • Corical
  • Lamellar
  • Sutural
  • Capsular 
  1. Congenital capsular thickening- Associated with posterior or anterior polar cataracts and pyramidal cataract. The posterior form may be associated with a hyaloid remnant.
  2. Acquired capsular opacities – Occur with pseudoexfoliation, Infra-red radiation (Glass blower’s cataract) or Secondary to blunt trauma when a Vossius’ ring may be formed. 
  • Subcapsular 
  1. Posterior subcapsular – Lens changes may be associated with secondary or complicated cataracts, drugs e.g., steroids, or be an age-related cataract (Cupuliform). 
  2. Anterior subcapsular  Anterior subcapsular lens changes may be associated with  Wilson’s disease (sunflower cataract) or with drugs e.g., amiodarone
  • Nuclear 
  1. Congenital – Nuclear cataract is that secondary to Rubella 
  2. Age-related – Nuclear sclerosis cataract commonly seen in practice is the age-related form.  
  • Cortical 
  1. Congenital – Congenital cortical cataract is very common and they rarely interfere with vision. e.g., blue dot cataract and coronary cataract.
  2. Age-related – Known as cuneiform cataract that takes the form of “water” clefts and vacuoles. These often appear first in the inferior nasal quadrant of the lens possibly because this is most exposed to UV radiation. 
  • Lamellar 
  1. Congenital – The cataracts are usually congenital and often involve one lamella of the fetal or nuclear zones. Radial, spoke-like opacities (or riders) also often surround the cataract. 
  • Sutural 
  1. These are often known as “Y”-shaped” cataract. 
Maturity
  • Immature Senile Cataract (IMSC) – partially opaque lens, disc view hazy
  • Mature Senile Cataract (MSC) – Completely opaque lens, no disc view
  • Hypermature Senile Cataract (HMSC) – Liquefied cortical matter: Morgagnian Cataract
  • Congenital cataract
  • Immature or incomplete – The cataract is present but not visually incapacitating. Surgery may or may not be indicated. 
  • Mature – The whole lens is opaque. Surgery is usually indicated. 
  • Intumescent – The lens is swollen. Surgery is indicated. 
  • Hypermature – The lens is shrunken, yellow and the capsule is wrinkled. 
  • Morganian cataract – A hypermature cataract with liquified cortex and in which the nucleus settles inferiorly. 
Location of opacity
  • Anterior cortical cataract
  • Anterior polar cataract
  • Anterior subcapsular cataract
  • Nuclear cataract
  • Posterior cortical cataract
  • Posterior polar cataract (importance lies in higher risk of complication – posterior capsular tears during surgery)
  • Posterior subcapsular cataract (PSC) (clinically common)
  • Anterior subcapsular lens changes may be associated with Wilson’s disease (sunflower cataract) or with drugs e.g., amiodarone
  • Posterior subcapsular cataract changes may associated with secondary or complicated cataracts, drugs e.g., steroids, or be an age related cataract.
Etiological
  • Congenital 
  • Degenerative or “age related” (senile) 
  • Traumatic 
  • Secondary to other conditions (including metabolic causes) 
  • Toxic 
  • Hereditary 
  • Congenital cataract – Result of heredity (often autosomal dominant), prenatal infections such as rubella or metabolic disorders. 
    1. Intrauterine infections e.g. Rubella and Toxoplasmosis. 
    2. Maternal drug ingestion e.g. Thalidomide and corticosteroids. 
    3. Genetically transmitted syndromes 
    4. Microphthalmos
    5. Ocular conditions with associated anomalies e.g. Retinopathy of Prematurity and some types of retinitis pigmentosa. 
    6. Secondary to metabolic disorders e.g. Galactosemia and Wilson’s disease
  • Degenerative or “Age-Related” (senile)– Most adults have some degree of opacification of the lens and therefore technically exhibit cataract. 
    1. Subcapsular Anterior subcapsular cataract (directly under the capsule) is associated with fibrous metaplasia of anterior lens epithelium. Posterior subcapsular cataract (cupuliform) lies just in front of the posterior capsule and is associated with posterior migration of epithelial cells. 
    2. Cortical cataract commonly develops as radial or spoke-shaped “water-clefts” (cuneiform) together with vacuoles. Cuneiform changes affect anterior, posterior and equatorial cortex affected.
    3. Nuclear sclerosis  Nuclear cataract is an exacerbation of the normal aging of lens nucleus and appears as a yellowing of the nucleus. 
  • Traumatic – Trauma is the commonest cause of unilateral cataract in young individuals. Opacities can be the result of various injuries including penetrating injury. Concussion to the eye may cause the iris to be flattened against the lens leaving a Vossius’ ring. 
  • Secondary – Cataract can occur secondary to systemic disease or syndromes including metabolic disorders and due to local disease (ocular). 
    • Secondary to systemic diseases/metabolic disorders
      1. Diabetes – Diabetes mellitus can cause an exacerbation of the progression of age-related degenerative changes. So-called (classical) diabetic cataract occurs during an acute and untreated hyperglycaemic episode and takes the form of cortical “snowflakes”. These occur due to osmotic over-hydration of the lens and can be anterior and/or posterior in position. 
      2. Galactosaemia – This metabolic disease produces an “oil droplet” cataract. 
      3. Wilson’s disease (hepatolenticular degeneration) – This is an anomaly of copper metabolism and produces a ring of copper in the peripheral cornea (Kayser-Fleischer ring) and a greenish colored “sunflower cataract” 
      4. Atopic dermatitis – Cataract can occur secondary to atopic dermatitis and takes the form of bilateral posterior or anterior stellate opacities. 
      5. Down’s syndrome – 15% of Down’s have lens opacities severe enough to cause a decrease in acuity (Kanski, 1998) and with a reported prevalence of up to 50% (Scully, 1973). 
    • Secondary to local disease (or complicated cataract) 
      1. Anterior uveitis – Anterior uveitis can produce a posterior polar polychromatic cataract. Also, if uveitis not controlled, anterior and posterior subcapsular opacities can progress to complete opacification. 
      2. High myopia – Hight myopia can be associated with secondary posterior lens opacities as well as the earlier development of nuclear sclerosis. 
      3. Glaukomflecken – These are grey-white anterior capsular or subcapsular opacities in pupillary zone pathognomonic with previous attacks of acute angle-closure glaucoma. 
  • Toxic 
    1. Corticosteroids – Steroids used for prolonged therapy produce a posterior subcapsular cataract. 
    2. Amiodarone – Amiodarone can cause anterior capsular changes in up to 50% of patients. The opacities tend to be visually insignificant. 

References

  1. ↑ 1.0 1.1 1.2 Miller KM, Oetting TA, Tweeten JP, et al; American Academy of Ophthalmology Preferred Practice Pattern Cataract/Anterior Segment Panel. Cataract in the adult eye preferred practice pattern. Ophthalmology. 2022;129(1):1-P126. doi:10.1016/j. ophtha.2021.10.006
  2. ↑ Delcourt C, Cougnard-GrĂ©goire A, Boniol M, et al. Lifetime exposure to ambient ultraviolet radiation and the risk for cataract extraction and age-related macular degeneration: the Alienor Study. Invest Ophthalmol Vis Sci. 2014;55(11):7619- 7627. doi:10.1167/iovs.14-14471

Template:WS Template:WH

Pathophysiology

Pathophysiology

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] , Associate Editor-In-Chief: Joseph Nasr, M.D.[2]

Please help WikiDoc by adding content here. It’s easy! Click here to learn about editing.

Pathophysiology

The crystalline lens is an avascular structure composed of elongated fiber cells that are densely packed with specialized proteins known as crystallins, whose precise spatial organization and hydration are essential for maintaining lens transparency. The cytoskeleton of lens fiber cells contributes to their characteristic shape, while membrane protein channels regulate ionic and osmotic balance across the lens, supporting normal optical function.[1]


Lens transparency is preserved in part by protection of protein-bound sulfhydryl groups against oxidation through high intracellular concentrations of reduced glutathione. Crystallins exhibit long-term structural stability and are capable of absorbing short-wavelength visible light, ultraviolet radiation, and infrared radiation while maintaining transparency, thereby providing a protective role for enzymatic activity within the lens.[1]


With aging, progressive oxidative stress leads to an imbalance between the generation of reactive oxygen species and the lens’s ability to detoxify reactive intermediates or repair oxidative damage. Disruption of cellular redox homeostasis results in oxidative injury to proteins, lipids, and nucleic acids within lens cells.[1]


Age-related oxidative processes promote protein modification, aggregation, and insolubilization, resulting in increased light scattering and loss of lens transparency. Accumulation of damaged and aggregated crystallins contributes to breakdown of fiber cell membranes and progressive opacification of the lens.[1]


Aging also reduces the metabolic efficiency of the lens, increasing susceptibility to environmental and metabolic stressors. Alterations in glucose metabolism, impaired protein synthesis and transport, and declining membrane repair capacity further predispose the lens to cataract formation.[1]


Because mature lens fiber cells are denucleated and lack the ability to replace damaged components, maintenance of metabolic homeostasis depends on the lens epithelium and a limited population of metabolically active fiber cells. Progressive failure of this system results in steep metabolic gradients within the lens and contributes to localized opacities, including wedge-shaped or sectoral cataracts.[1]


Lens epithelial cells are continuously exposed to light and radiation stress, which may induce genetic and cellular damage. As defective cells cannot be extruded, they may undergo degradation or migrate toward the posterior capsule, where they contribute to the development of posterior subcapsular cataracts.[1]

References

  1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Chen SP, Woreta FA, Chang DF. Cataracts: A Review. JAMA. 2025;333(23):2093–2103. doi:10.1001/jama.2025.1597

Template:WS Template:WH

Causes

Causes

Please help WikiDoc by adding more content here. It’s easy! Click here to learn about editing.

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] , Associate Editor-In-Chief: Joseph Nasr, M.D.[2]

Causes

Cataracts develop as a result of processes that disrupt the normal structure, organization, and transparency of the crystalline lens, most commonly due to denaturation and aggregation of lens proteins. Aging is the most common cause of cataract formation and reflects the cumulative effects of metabolic and oxidative stress on lens proteins and fiber cells over time.

Systemic diseases may contribute to cataract development. Diabetes mellitus is associated with earlier onset of cataracts, likely due to chronic metabolic stress within the lens related to hyperglycemia.

Environmental and occupational exposures also play an important role. Long-term ultraviolet radiation exposure, ionizing radiation, and infrared radiation are associated with increased risk of cataract formation. Commercial airline pilots have been reported to have a higher prevalence of cataracts than individuals in non-flying occupations, likely due to increased exposure to cosmic radiation.[1] Cataracts are also unusually common in individuals exposed to infrared radiation, such as glassblowers, and exposure to microwave radiation has been reported to induce cataract formation.

Certain medications are known to induce cataracts. Prolonged corticosteroid use is a well-recognized cause, particularly associated with the development of posterior subcapsular cataracts.[2][3] Other medications reported to be associated with cataract development include ciclesonide, ezetimibe, and oxcarbazepine.

Cataracts may also result from ocular trauma, including blunt or penetrating injury, as well as from prior intraocular surgery or chronic intraocular inflammation. Congenital and genetic factors are important causes of cataracts presenting at birth or early in life, and a positive family history may predispose individuals to cataract development at a younger age, a phenomenon described as anticipation in presenile cataracts.

Cataracts may be partial or complete, stationary or progressive, and may vary in consistency from soft to hard. They are further classified by morphology (e.g., nuclear, cortical, mature, hypermature) and by anatomic location (e.g., posterior, classically associated with steroid use, and anterior, commonly related to aging).[4]

Causes by Organ System

Cardiovascular No underlying causes
Chemical/Poisoning No underlying causes
Dental No underlying causes
Dermatologic No underlying causes
Drug Side Effect Aflibercept, Beclometasone dipropionate, Clomifene, Ciclesonide, Cidofovir, Corticosteroids, Deferasirox, Desogestrel and Ethinyl Estradiol, Dexamethasone, Difluprednate, Eltrombopag, Ezetimibe, Nilutamide, Oxcarbazepine, Pegaptanib, Pramipexole, Tafluprost, Travoprost
Ear Nose Throat No underlying causes
Endocrine No underlying causes
Environmental No underlying causes
Gastroenterologic No underlying causes
Genetic No underlying causes
Hematologic No underlying causes
Iatrogenic No underlying causes
Infectious Disease No underlying causes
Musculoskeletal/Orthopedic No underlying causes
Neurologic No underlying causes
Nutritional/Metabolic No underlying causes
Obstetric/Gynecologic No underlying causes
Oncologic No underlying causes
Ophthalmologic No underlying causes
Overdose/Toxicity No underlying causes
Psychiatric No underlying causes
Pulmonary No underlying causes
Renal/Electrolyte No underlying causes
Rheumatology/Immunology/Allergy No underlying causes
Sexual No underlying causes
Trauma No underlying causes
Urologic No underlying causes
Miscellaneous No underlying causes

Causes in Alphabetical Order

List the causes of the disease in alphabetical order. You may need to list across the page, as seen here

References

  1. ↑ Rafnsson, V. “Cosmic radiation increases the risk of nuclear cataract in airline pilots: a population-based case-control study”. Arch Ophthalmol. 123: 1102–1105. Unknown parameter |coauthors= ignored (help)
  2. ↑ SPENCER R, ANDELMAN S. “STEROIDSAREBAD CATARACTS. POSTERIOR SUBCAPSULAR CATARACT FORMATION IN RHEUMATOID ARTHRITIS PATIENTS ON LONG TERM STEROID THERAPY”. Arch Ophthalmol. 74: 38–41. PMID 14303339.
  3. ↑ Greiner J, Chylack L (1979). “Posterior subcapsular cataracts: histopathologic study of steroid-associated cataracts”. Arch Ophthalmol. 97 (1): 135–44. PMID 758890.
  4. ↑ Chen SP, Woreta FA, Chang DF. Cataracts: A Review. JAMA. 2025;333(23):2093–2103. doi:10.1001/jama.2025.1597

Template:WS Template:WH

Differentiating Cataract from other Diseases

Differentiating Cataract from other Diseases

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] , Associate Editor-In-Chief: Joseph Nasr, M.D.[2]

Please help WikiDoc by adding content here. It’s easy! Click here to learn about editing.


Cataracts must be differentiated from other ocular conditions that cause decreased vision, including refractive error, glaucoma, age-related macular degeneration, diabetic retinopathy, and optic neuropathies. Unlike retinal or optic nerve disease, cataracts impair vision by causing light scatter, glare, and reduced contrast sensitivity rather than disruption of neural signal transmission.[1]

Slit-lamp biomicroscopy following pupillary dilation allows direct visualization of lens opacification, confirming cataract as the primary cause of visual impairment. In contrast, disorders such as macular degeneration or glaucoma may present with relatively clear lenses but abnormal funduscopic findings or visual field defects.[2]

Changes in refractive error, particularly myopic shifts associated with nuclear cataracts, may temporarily improve near vision and mask the severity of lens opacity, necessitating careful examination to distinguish cataract-related visual decline from refractive causes alone.[2]

References

  1. ↑ Liu YC, Wilkins M, Kim T, Malyugin B, Mehta JS. Cataracts. Lancet. 2017;390(10094):600-612. doi:10.1016/S0140-6736(17)30544-5
  2. ↑ 2.0 2.1 Miller KM, Oetting TA, Tweeten JP, et al; American Academy of Ophthalmology Preferred Practice Pattern Cataract/Anterior Segment Panel. Cataract in the adult eye preferred practice pattern. Ophthalmology. 2022;129(1):1-P126. doi:10.1016/j. ophtha.2021.10.006

Template:WS Template:WH

Epidemiology and Demographics

Epidemiology and Demographics

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] , Associate Editor-In-Chief: Joseph Nasr, M.D.[2]

Epidemiology and Demographics

Cataracts are a leading cause of visual impairment and blindness worldwide. In 2020, cataracts accounted for an estimated 15 million cases of blindness and 79 million cases of moderate to severe visual impairment among adults aged 50 years or older (GBD 2019 Blindness and Vision Impairment Collaborators, 2021).[1] The prevalence of cataracts increases markedly with age, affecting more than two-thirds of individuals older than 80 years. [2][3]

In the United States, age-related lenticular changes are common and increase substantially with advancing age. National estimates project that the number of individuals with cataracts will increase from 24.4 million in 2010 to approximately 50 million by 2050, largely due to population aging. [2][3]

Cataract prevalence is not evenly distributed across populations. In the United States, cataracts are disproportionately more prevalent among women, individuals of lower socioeconomic status, and racial and ethnic minority populations, including Asian, Black, Hispanic, and Native American individuals.[4]. These populations are also more likely to present with severe vision impairment at the time of cataract surgery, underscoring persistent disparities in access to timely ophthalmic care.[5]

Globally, access to cataract surgery varies substantially. In low- and middle-income countries, treatable cataract accounts for up to 50% of blindness, compared with approximately 5% in high-income countries, reflecting disparities in surgical capacity and health-care infrastructure.[1][6] Lower cataract surgery rates in these regions contribute significantly to the continued global burden of cataract-related blindness.[7][8]

References

  1. ↑ 1.0 1.1 GBD 2019 Blindness and Vision Impairment Collaborators; Vision Loss Expert Group of the Global Burden of Disease Study. Causes of blindness and vision impairment in 2020 and trends over 30 years, and prevalence of avoidable blindness in relation to VISION 2020: the Right to Sight: an analysis for the Global Burden of Disease Study. Lancet Glob Health. 2021;9(2):e144-e160. doi:10.1016/S2214-109X(20)30489-7
  2. ↑ 2.0 2.1 Chen SP, Azad AD, Pershing S. Bidirectional association between visual impairment and dementia among older adults in the United States over time. Ophthalmology. 2021;128(9):1276-1283. doi:10.1016/j.ophtha.2021.02.021
  3. ↑ 3.0 3.1 Cataract tables. National Eye Institute. Accessed July 23, 2024. https://www.nei.nih.gov/learn- about-eye-health/eye-health-data-and-statistics/ cataract-data-and-statistics/cataract-tables
  4. ↑ Elam AR, Tseng VL, Rodriguez TM, Mike EV, Warren AK, Coleman AL; American Academy of Ophthalmology Taskforce on Disparities in Eye Care. Disparities in vision health and eye care. Ophthalmology. 2022;129(10):e89-e113. doi:10.1016/ j.ophtha.2022.07.010
  5. ↑ Awidi AA, Woreta FA, Sabit A, et al. The effect of racial/ethnic and socioeconomic differences on visual impairment prior to cataract surgery. Ophthalmology. 2025;132(1):98-107. doi:10.1016/j. ophtha.2024.07.021
  6. ↑ Liu YC, Wilkins M, Kim T, Malyugin B, Mehta JS. Cataracts. Lancet. 2017;390(10094):600-612. doi:10.1016/S0140-6736(17)30544-5
  7. ↑ Tabin G, Chen M, Espandar L. Cataract surgery for the developing world. Curr Opin Ophthalmol. 2008;19(1):55-59. doi:10.1097/ICU. 0b013e3282f154bd
  8. ↑ Venkatesh R, Chang DF, Muralikrishnan R, Hemal K, Gogate P, Sengupta S. Manual small incision cataract surgery: a review. Asia Pac J Ophthalmol (Phila). 2012;1(2):113-119. doi:10.1097/ APO.0b013e318249f7b9

Template:WS Template:WH

Risk Factors

Risk Factors

Please help WikiDoc by adding more content here. It’s easy! Click here to learn about editing.

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] , Associate Editor-In-Chief: Joseph Nasr, M.D.[2]

Risk Factors

Advanced age is the most important risk factor for cataract development, reflecting cumulative biochemical and structural changes within the crystalline lens.[1]

Systemic conditions associated with increased cataract risk include diabetes mellitus, which accelerates lens opacification through metabolic and osmotic mechanisms affecting lens proteins.[2]

Lifestyle and environmental risk factors include cigarette smoking, excessive alcohol consumption, and ultraviolet radiation exposure, all of which increase oxidative stress within the lens.[2]

Medication-related risk factors include prolonged use of systemic or topical corticosteroids, which are strongly associated with posterior subcapsular cataract formation.[3]

Ocular conditions such as uveitis, high myopia, ocular trauma, and prior intraocular surgery are also associated with increased risk of cataract development.[3]

References

  1. ↑ GBD 2019 Blindness and Vision Impairment Collaborators; Vision Loss Expert Group of the Global Burden of Disease Study. Causes of blindness and vision impairment in 2020 and trends over 30 years, and prevalence of avoidable blindness in relation to VISION 2020: the Right to Sight: an analysis for the Global Burden of Disease Study. Lancet Glob Health. 2021;9(2):e144-e160. doi:10.1016/S2214-109X(20)30489-7
  2. ↑ 2.0 2.1 Liu YC, Wilkins M, Kim T, Malyugin B, Mehta JS. Cataracts. Lancet. 2017;390(10094):600-612. doi:10.1016/S0140-6736(17)30544-5
  3. ↑ 3.0 3.1 Miller KM, Oetting TA, Tweeten JP, et al; American Academy of Ophthalmology Preferred Practice Pattern Cataract/Anterior Segment Panel. Cataract in the adult eye preferred practice pattern. Ophthalmology. 2022;129(1):1-P126. doi:10.1016/j. ophtha.2021.10.006

Template:WS Template:WH

Screening

Screening

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] , Associate Editor-In-Chief: Joseph Nasr, M.D.[2]

Please help WikiDoc by adding content here. It’s easy! Click here to learn about editing.

Screening

Cataracts are identified through routine comprehensive ophthalmologic examination rather than population-based laboratory testing or imaging studies. Slit-lamp examination following pupillary dilation remains the primary method for detecting and classifying lens opacities.[1]

Screening for cataracts is typically incorporated into periodic eye examinations, particularly in older adults and individuals with known risk factors such as diabetes mellitus, corticosteroid use, or significant ultraviolet exposure.[1]

Early identification of cataracts allows monitoring of disease progression and timely referral for surgical evaluation when visual impairment becomes functionally significant.[1]

References

  1. ↑ 1.0 1.1 1.2 Miller KM, Oetting TA, Tweeten JP, et al; American Academy of Ophthalmology Preferred Practice Pattern Cataract/Anterior Segment Panel. Cataract in the adult eye preferred practice pattern. Ophthalmology. 2022;129(1):1-P126. doi:10.1016/j. ophtha.2021.10.006

Template:WS Template:WH

Natural History, Complications and Prognosis

Natural History, Complications and Prognosis

Please help WikiDoc by adding more content here. It’s easy! Click here to learn about editing.

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1], Associate Editor-In-Chief: Joseph Nasr, M.D.[2]

Natural History, Complications & Prognosis

Cataracts typically develop gradually and progressively, resulting in painless decline in visual acuity over time. Early symptoms may include blurred vision, glare, difficulty with night driving, and reduced contrast sensitivity. As lens opacity advances, visual impairment worsens and may interfere with activities of daily living.[1]

If left untreated, cataracts can progress to severe visual impairment or blindness. Visual loss from cataracts has been associated with reduced independence and decreased quality of life in affected individuals.[2]

Surgical removal of the cataract is associated with substantial improvement in visual function and quality of life. Prognosis following cataract surgery is generally favorable when no significant ocular comorbidities are present.[3]

References

  1. ↑ Liu YC, Wilkins M, Kim T, Malyugin B, Mehta JS. Cataracts. Lancet. 2017;390(10094):600-612. doi:10.1016/S0140-6736(17)30544-5
  2. ↑ GBD 2019 Blindness and Vision Impairment Collaborators; Vision Loss Expert Group of the Global Burden of Disease Study. Causes of blindness and vision impairment in 2020 and trends over 30 years, and prevalence of avoidable blindness in relation to VISION 2020: the Right to Sight: an analysis for the Global Burden of Disease Study. Lancet Glob Health. 2021;9(2):e144-e160. doi:10.1016/S2214-109X(20)30489-7
  3. ↑ Miller KM, Oetting TA, Tweeten JP, et al; American Academy of Ophthalmology Preferred Practice Pattern Cataract/Anterior Segment Panel. Cataract in the adult eye preferred practice pattern. Ophthalmology. 2022;129(1):1-P126. doi:10.1016/j. ophtha.2021.10.006

Template:WS Template:WH

Diagnosis

Diagnosis

History and Symptoms | Physical Examination | Laboratory Findings | X Ray | CT | MRI | Other Imaging Findings | Other Diagnostic Studies

Treatment

Treatment

Medical Therapy | Surgery | Primary Prevention | Secondary Prevention | Cost-Effectiveness of Therapy | Future or Investigational Therapies

Case Studies

Case Studies

Case #1

Related Chapters

ca:Cataracta de:Katarakt (Medizin) eo:Katarakto eu:Begi-lauso fa:۹ۚ Ù…Ű±ÙˆŰ§Ű±ÛŒŰŻ hr:Katarakta id:Katarak it:Cataratta he:Ś§Ś˜ŚšŚ§Ś˜ lt:Katarakta hu:SzĂŒrkehĂĄlyog ms:Katarak nl:Grijze staar no:Katarakt nn:Katarakt qu:Phuyu ñawi simple:Cataract sr:КатараĐșта fi:Harmaakaihi sv:GrĂ„ starr


Template:WikiDoc Sources

Looking for the patient version?

Back to the patient-friendly article

Imprint

Privacy Policy

Terms and Conditions

© 2026 MyEClinic – IFTM Institut fĂŒr Telematik in der Medizin GmbH