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Cataract in the 21st century

Cataract in the 21st century

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Cataract in the 21st century

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  1. Cataract in the 21st century • Liana Al-Labadi, O.D. • Lecture 7 • Thanks To The Ohio State College of Optometry

  2. The Lens • The human lens is a naturally clear structure located behind the iris & supported by the zonules • The lens is avascular- no vascular supply • The lens consists of a central nucleus surrounded by the cortex and contained within the lens capsule Solomon, R. et al. JAMA 2003;290:248-251

  3. The lens • The optics • Light passes through the pupil--> focused by the lens to produce clear, sharp images on the retina • When this arrangement is disturbed in any way--> transparency is lost--> scattering of light, blurring & blocking of the image http://www.pnkeyecare.com/images/imgCataract.jpg

  4. Cataract development • The lens is made mostly of water & protein fibers • The eye lens is made up of densely packed crystalline proteins, arranged in such a way that light in the visible wavelength range can pass through • For various reasons (UV & Age), the the proteins sometimes change their behavior and the structure of protein fibers breaks down • This leads to development of protein clumps--> lens clouding--> loss of lens transparency--> light blocked from reaching the retina--> cloudy vision & blindness--> Cataract development • There is no way to reverse this protein aggregation process once it has begun

  5. Cataract development • New insights on cataract formations • Protein interactions--> cataract development • Finely tuned combination of attraction & repulsion between proteins results in an arrangement that was transparent to light- this attraction is actually a weak one • Results indicate that cataracts forms if this balance of attraction is disrupted • Proteins either separate • Proteins form clumps http://www.sciencedaily.com/releases/2007/11/071109100159.htm

  6. Cataract risk factors • Demographic RF • Age- The strongest RF for cataract • The risk of cataract at age 70 is about 13-fold that at age 50 • Race • Some types of cataracts (cortical & nuclear) are more common in african americans • Sex • Women slightly greater risk than men • Geographic • Especially prevalent in developing countries in the tropical belt

  7. Cataract risk factors • Medical RF • Diabetes • Diabetics under age 70 have an excess prevalence of age-related cataract • After age 70 the excess appears to be less • Family history- very minimal RF • Drugs • Corticosteroids & phenothiazines • Miotic cholinergic compounds • Cancer chemotherapy agents • Diuretics • Various photosenthesitizing drugs • Major tranquillizers • Gout medications

  8. Cataract risk factors • Environmental RF • Nutrition- conflicting reports • Dietary intake of riboflavin, vit C &E & carotenoids (antioxidants)- protective effect • Intake of niacin, thiamine & iron- also protective • Radiation • Exposure to UV--> cortical & PSC • IR • Smoking- increased risk of nuclear cataracts • Alcohol use • > 2 drinks/ day--> increased risk of all types of cataract

  9. Cataract Symptoms • Effects of cataract on vision: • Decreased visual acuity over months to years affecting one or both eyes • Monocular diplopia • Glare- particularly from oncoming headlights while driving at night • Color changes- reduced color perception • Dimmed vision The Ohio State College of Optometry

  10. Cataract Signs • Effects of cataract on vision: • Opacification of the normally clear crystalline lens • Myopic shift or so-called “second sight” • Astigmatic changes • Field loss • Blurred view of the retina with dimming of red reflex on retinoscopy • Decreased contrast sensitivity • A cataract alone does not cause an APD

  11. Cataract Etiology

  12. Age-Related Ctataract • Classification According to Morphology • Subcapsular • Anterior • Posterior • Nuclear • Cortical • Christmas tree http://2.bp.blogspot.com/_5qgbDGvLPO8/R1LXfVUgVtI/AAAAAAAAABs/q0Tp4rBeUEw/s1600-R/lens_3.jpg

  13. Age-Related CAtaract • Types of Cataracts- Posterior Subcapsular Cataract (PSC) • Plaque-like opacity near the posterior aspect of the lens • Begins at the back of the lens & spreads to the periphery or edges of lens • Appears as a white ground glass or swiss cheese like opacity • Often associated with lots of vacuoles • Best seen in retroillumination against the red reflex • Occurs in younger patients (<50 years) • Rapid onset • Common complaints: glare & reading difficulties • Near vision is always worst than distance vision for these patients • Associated with: • Ocular inflammation & steroid use • Diabetes • Trauma & Radiation http://www.cataractsurgery.com/learn-about-cataracts/types-of-cataracts.asp http://www.opt.indiana.edu/NewHorizons/PSC.html

  14. PSC (From Effects of A-bomb Radiation on the Human Body, ed by HICARE in 1991. Courtesy of Bunkodo Co, Ltd., Tokyo.)

  15. PSC http://www.opt.indiana.edu/NewHorizons/PSC.html

  16. http://dro.hs.columbia.edu/psc.htm http://www.aapos.org/client_data/files/230_cataract4.jpg PSC http://dro.hs.columbia.edu/psc.htm http://www.opt.indiana.edu/riley/HomePage/Age_related_Cats/2Text_age_related_cats.html

  17. http://dro.hs.columbia.edu/psc.htm http://sonorandeserteyecare.com/2009/06/posterior-subcapsular-cataract-2/ PSC http://dro.hs.columbia.edu/psc.htm http://sonorandeserteyecare.com/2009/06/posterior-subcapsular-cataract-2/

  18. Age-Related CAtaract • Types of Cataracts- Anterior Subcapsular Cataract (ASC) • Subtle Y or star-shaped opacity in the anterior axial subcapsular area • Composed of brownish punctate opacities • More prevalent in younger populations & in males • Risk factors: • Strongly associated with ocular trauma • Atopic keratoconjunctivitis/ Atopic dermatitis • Retinoblastoma • Medications • Anti-psychotics (Chlorpromazine) • Anti-arrhythmic drugs (Amiodarone) • Histopathology: Transdifferentiation of the lens epithelial cells into myofibroblasts • Myofibroblasts do no express type IV collagen--> abnormal secretion of extracellular matrix--> loss of lens clarity (From Effects of A-bomb Radiation on the Human Body, ed by HICARE in 1991. Courtesy of Bunkodo Co, Ltd., Tokyo.)

  19. http://www.opt.indiana.edu/NewHorizons/PSC.html http://www.opt.indiana.edu/NewHorizons/PSC.html ASC

  20. ASC http://www.eyeweb.org/atlas/cataract/ascp_com.jpg

  21. http://66.230.4.1/som/ophthalmology/eyeatlas/Lens/Traumatic%20Anterior%20Subcapsular%20Cataract%20Retroillumination.aspxhttp://66.230.4.1/som/ophthalmology/eyeatlas/Lens/Traumatic%20Anterior%20Subcapsular%20Cataract%20Retroillumination.aspx http://www.nature.com/eye/journal/v21/n1/fig_tab/6702181f2.html#figure-title Traumatic ASC http://cms.revoptom.com/index.asp?page=2_14231.htm

  22. Age-Related CAtaract • Types of Cataracts- Nuclear Sclerotic Cataract (NS) • Most common type of cataract • Generalized haziness of the lens • Yellow or brown discoloration of the central lens (brunescence) • The nucleus at the center of the lens is becoming opaque • Typically blurs distance vision more than near (i.e. Myopic shift) • Decreased BCVA • Affects the geriatric population >50-60 years old • When grading NS judge the color of nucleus as well as the BCVA http://www.cataractsurgery.com/learn-about-cataracts/types-of-cataracts.asp

  23. NS http://dro.hs.columbia.edu/ns.htm http://dro.hs.columbia.edu/ns.htm

  24. \ NS http://www.opt.indiana.edu/NewHorizons/NS.html

  25. Age-Related CAtaract • Types of Cataracts- Cortical Cataract (CC) • Radial or spoke-like opacities in the periphery that expand to involve the anterior and posterior lens • Usually begins in the inferio-nasal quadrant (~d/t sun exposure) • Early stage: CC demonstrates water clefts & vacuoles • Late stage: CC demonstrates spoke-like or wedge-shaped peripheral opacities that progress circumferentially, intitally sparing the central axis of the lens • Can cause glare • Often asymptomatic until central changes develop • Affects geriatric population >55+ • Associated with NS • To grade: Divide the frontal (retro) view into quadrants http://www.cataractsurgery.com/learn-about-cataracts/types-of-cataracts.asp http://www.opt.indiana.edu/NewHorizons/PSC.html

  26. CC http://www.opt.indiana.edu/NewHorizons/PSC.html

  27. http://dro.hs.columbia.edu/ns.htm http://dro.hs.columbia.edu/ns.htm CC The Ohio State College of Optometry

  28. Age-Related Cataract • Classification According to Morphology- Christmas-Tree • Subcapsular • Anterior • Posterior • Nuclear • Cortical • Christmas tree http://2.bp.blogspot.com/_5qgbDGvLPO8/R1LXfVUgVtI/AAAAAAAAABs/q0Tp4rBeUEw/s1600-R/lens_3.jpg

  29. Age-Related Cataract • Classification According to Maturity • Immature • Mature • Hypermature • Morgagnian http://2.bp.blogspot.com/_5qgbDGvLPO8/R1LXfVUgVtI/AAAAAAAAABs/q0Tp4rBeUEw/s1600-R/lens_3.jpg