cataracts
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Introduction
An opacity of the crystalline lens of the eye; a loss of transparency of the lens of the eye or of its capsule.
Etiology
(risk factors)
Epidemiology
- 45-60% of individuals > 75 years of age
- prevalence may approach 100% in persons age > 90
- most common cause of reversible blindness in USA
- 2nd most common cause of blindness in USA
- among older diabetics, more common cause of visual disability than diabetic retinopathy
- cataract extraction is the most frequently performed surgical intervention on the Medicare population
- more common among persons with lower education & socioeconomic class
Pathology
- damage to the major lens crystallin proteins causes their misfolding & aggregation into insoluble amyloids resulting in opacification of the crystalline lens[12]
Genetics
- defects in CHMP4B associated with autosomal dominant cataract posterior polar type 3
Clinical manifestations
- diminished vision in one or both eyes
- lenticular opacities
- glare sensitivity[8]
- generalized blurry vision[8]
- diminished ability to see objects in dim light (contrast sensitivity)
- myopic shift in eyeglass prescription[11][12]
Laboratory
- ophthalmoscopy - reduction in the red reflex
- slit-lamp examination
- lenticular opacities may be observed with 1 & 2
Complications
- older drivers with cataracts were 2.5 times more likely to have a history of at fault motor vehicle accidents
- angle closure glaucoma
- glaucoma, cataracts, & age-related macular degeneration may increase risk of falls in the elderly[17]
Management
- surgery
- indications:
- diabetic retinopathy: monitoring requires a clear lens
- vision worse than 20/40
- visual function interferes with life function
- procedures:
- lens implantation
- extracapsular approach
- leaves posterior capsule of lens in place
- permits posterior chamber lens implants
- reduces incidence of post-operative complications
- phacoemulsification
- ultrasonic vibrations to remove lens
- requires smaller incision
- shorter period of post-operative visual rehabilitation
- YAG laser capsulotomy for post-operative opacification
- routine perioperative evaluation unnecessary[3]
- indications:
- tight control of diabetes
- vitamin/mineral supplementation (antioxidants?) may provide some protective benefit[4][5]
- vitamin A & beta-carotene, vitamin C, zinc
- Ocuvite Preservision
- vit E, riboflavin & thiamine supplements may reduce progression of age-related lens opacification[6]
- use of statins may be associated with reduced risk[7]
- UV light filters (sunglasses)
Comparative biology
- lanosterol reverses protein aggregation in cataracts (in vitro, rabbits, dogs)[12]
- molecules that bind to alpha-crysallin & prevent their misfolding & aggregation may improve crystalline lens transparency[12]
More general terms
More specific terms
- anterior cortical cataract (ACC)
- congenital cataracts
- cortical cataract
- familial cataracts
- glaucomatous flecks; glaukomflecken
- nuclear sclerosis
- nuclear sclerotic cataracts (NSC)
- posterior subcapsular cataract (PSC)
Additional terms
References
- ↑ Harrison's Principles of Internal Medicine, 13th ed. Companion Handbook, Isselbacher et al (eds), McGraw-Hill Inc. NY, 1995, pg 829-39.
- ↑ DeGowin & DeGowin's Diagnostic Examination, 6th edition, RL DeGowin (ed), McGraw Hill, NY 1994, pg 872
- ↑ 3.0 3.1 Medical Knowledge Self Assessment Program (MKSAP) 11, 15, American College of Physicians, Philadelphia 1998, 2009
- ↑ 4.0 4.1 Journal Watch 21(1):3, 2001 Mares-Perlman et al Arch Ophthalmol 118:1556, 2000
- ↑ 5.0 5.1 Mangione C. In: Intensive Course in Geriatric Medicine & Board Review, Marina Del Ray, CA, Sept 12-15, 2001
- ↑ 6.0 6.1 Jacques PF, Taylor A, Moeller S Long-term nutrient intake and 5-year change in nuclear lens opacification, Archives of Ophthalmology 123:517, 2005
- ↑ 7.0 7.1 Klein BEK et al, Statin use and incident nuclear cataract. JAMA 2006; 295:2752 PMID: https://www.ncbi.nlm.nih.gov/pubmed/16788130
- ↑ 8.0 8.1 8.2 Geriatric Review Syllabus, 7th edition Parada JT et al (eds) American Geriatrics Society, 2010
- ↑ Asbell PA, Dualan I, Mindel J, Brocks D, Ahmad M, Epstein S. Age-related cataract. Lancet. 2005 Feb 12-18;365(9459):599-609. PMID: https://www.ncbi.nlm.nih.gov/pubmed/15708105
- ↑ Bienfang DC, Kelly LD, Nicholson DH, Nussenblatt RB Ophthalmology. N Engl J Med. 1990 Oct 4;323(14):956-67. PMID: https://www.ncbi.nlm.nih.gov/pubmed/2205800
- ↑ 11.0 11.1 Delcourt C et al. Risk factors for cortical, nuclear, and posterior subcapsular cataracts: the POLA study. Am J Epidemiol 2000 Mar 9; 151:497-504 PMID: https://www.ncbi.nlm.nih.gov/pubmed/11004323
- ↑ 12.0 12.1 12.2 12.3 12.4 Zhao L et al. Lanosterol reverses protein aggregation in cataracts. Nature 2015 Jul 30; 523:607. PMID: https://www.ncbi.nlm.nih.gov/pubmed/26200341
Makley LN et al. Pharmacological chaperone for alpha-crystallin partially restores transparency in cataract models. Science 2015 Nov 6; 350:674. PMID: https://www.ncbi.nlm.nih.gov/pubmed/26542570
Quinlan RA. A new dawn for cataracts: Sterols reverse protein aggregation in an eye lens paradigm. Science 2015 Nov 6; 350:636. PMID: https://www.ncbi.nlm.nih.gov/pubmed/26542559 - ↑ Lamoureux EL, Fenwick E, Pesudovs K, Tan D. The impact of cataract surgery on quality of life. Curr Opin Ophthalmol. 2011 Jan;22(1):19-27. Review. PMID: https://www.ncbi.nlm.nih.gov/pubmed/21088580
- ↑ 14.0 14.1 Hobbs BN Seeing Red: Five Eye Diagnoses Not to Miss Medscape - Apr 23, 2018. https://www.medscape.com/viewarticle/895295
- ↑ Iroku-Malize T, Kirsch S. Eye Conditions in Older Adults: Cataracts. FP Essent. 2016 Jun;445:17-23. PMID: https://www.ncbi.nlm.nih.gov/pubmed/ 27348528 Review.
- ↑ Pelletier AL, Rojas-Roldan L, Coffin J. Vision Loss in Older Adults. Am Fam Physician. 2016 Aug 1;94(3):219-26. PMID: https://www.ncbi.nlm.nih.gov/pubmed/27479624 Free article. Review.
- ↑ 17.0 17.1 Tsang JY et al. Risk of falls and fractures in individuals with cataract, age-related macular degeneration, or glaucoma. JAMA Ophthalmol 2023 Dec 28; [e-pub]. PMID: https://www.ncbi.nlm.nih.gov/pubmed/38153708 https://jamanetwork.com/journals/jamaophthalmology/fullarticle/2813168