Cataracts

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Contents 1 More Specific Terms 2 Introduction 3 Etiology 4 Epidemiology 5 Clinical-manifestations 6 Laboratory 7 Complications 8 Management 9 More General Terms 10 Additional Terms 11 References

More Specific Terms

• anterior cortical cataract (ACC)
• cortical cataract
• familial cataracts
• nuclear sclerosis
• nuclear sclerotic cataracts (NSC)
• posterior subcapsular cataract (PSC)

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)
• aging
• systemic disorders

• diabetes mellitus
• hypoparathyroidism
• hypothyroidism

• genetic abnormalities
• trauma
• pharmacologic causes:

• busulfan
• chlorambucil
• glucocorticoids
• phenothiazines
• phospholine iodide

• environmental

• diets low in antioxidants
• smoking
• UV radiation/ sunlight

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

Clinical-manifestations

• diminished vision in one or both eyes
• lenticular opacities
• glare [8]
• generalized blurry vision [8]

• diminished ability to see objects in dim light ( contrast sensitivity)

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

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]

• 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] 5 UV light filters (sunglasses)

More General Terms

• ocular lens disorder
• sign/symptom

Additional Terms

• cataract surgery
• contrast sensitivity (CS)
• yttrium aluminum garnet laser (YAG)

References

1. Harrison's Principles of Internal Medicine, 13th ed. Companion Handbook, Isselbacher et al (eds), McGraw-Hill Inc. NY, 1995, pg 829-39.
2. DeGowin & DeGowin's Diagnostic Examination, 6th edition, RL DeGowin (ed), McGraw Hill, NY 1994, pg 872
3. Medical Knowledge Self Assessment Program (MKSAP) 11, 15, American College of Physicians, Philadelphia 1998, 2009
4. Journal Watch 21(1):3, 2001 Mares-Perlman et al Arch Ophthalmol 118:1556, 2000
5. Mangione C. In: Intensive Course in Geriatric Medicine & Board Review, Marina Del Ray, CA, Sept 12-15, 2001
6. 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. Klein BEK et al, Statin use and incident nuclear cataract. JAMA 2006; 295:2752 PMID: [1]
8. Geriatric Review Syllabus, 7th edition Parada JT et al (eds) American Geriatrics Society, 2010
9. NIH Institute and Center Resources [2]
10. National Guideline Clearinghouse
    - Cataract in the adult eye. (American Academy of Ophthalmology) ngc-guideline: [3]

cataracts