Cataract

Aka: Cataract, Age-Related Cataract

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II. Epidemiology

  1. Most common cause of severe Visual Impairment in U.S.
  2. Present in 70% of patients older than 70 years old

III. Pathophysiology

  1. Opacification of the crystalline lens of the eye
  2. Stages of development
    1. Immature Cataract
      1. Opacities separated by areas of clear lens
    2. Mature Cataract
      1. Complete lens opacification
    3. Hypermature Cataract
      1. Lens cortex is liquefied
      2. Lens capsule looses fluid
        1. Risk of Inflammatory reaction
        2. Risk of secondary Glaucoma

IV. Locations

  1. Nuclear Cataracts
    1. Central lens (nucleus) becomes dense and sclerotic
    2. Discolored by yellow, brown or gray hue
  2. Cortical Cataracts
    1. Peripheral opacities
    2. Radiating spokes appearance on Slit Lamp exam
  3. Posterior Subcapsular Cataracts
    1. Most rapidly progressive
    2. Seen in younger patients and those on Corticosteroid

V. Risk factors

  1. Normal Aging (90% of cases)
  2. Tobacco Abuse
  3. Ocular UV-B light exposure
  4. Traumatic Injury to lens or capsule
  5. Comorbid conditions
    1. Diabetes Mellitus
    2. Hypoparathyroidism
    3. Myotonic Dystrophy
    4. Atopic Dermatitis
    5. Congenital Cataract
  6. Medication related
    1. Systemic Corticosteroid
    2. Topical EchothiophateIodide (Glaucoma treatment)

VI. Symptoms

  1. Progressive reduced Vision (usually bilateral)
    1. Patients report Clouding or fogging of Vision
    2. Nuclear Cataracts may improve site temporarily
      1. Cataract sclerosis changes shape of Lens nucleus
      2. Myopia may result and may correct Farsightedness
  2. Skewed Color Perception
    1. Lens becomes pigmented in nuclear sclerotic Cataracts
    2. Blues filtered out
    3. Color is shifted to yellow and red part of spectrum
  3. Diminished Vision in bright light
    1. Central opacities block light when pupil constricts
    2. Glare may also occur
    3. Reduced night Vision (with halos in Visual Fields)

VII. Signs

  1. Lenticular opacities of various shapes and degree
  2. Technique
    1. Set ophthalmoscope to +10
    2. View lens from 12 inches from patient's face
    3. Cataracts appear as dark areas against red pupil
    4. Red Reflex overall appears dull
  3. Consider dilating pupil for exam
    1. Phenylephrine hydrochloride Ophthalmic Solution
      1. Not Cycloplegic
      2. Does not affect close Vision

VIII. Management

  1. Assessment of concurrent eye disorder
    1. Glaucoma
    2. Retinal Detachment
    3. Macular Degeneration
    4. Retinal vascular occlusive disease
    5. Retinopathy of Diabetes
    6. Hypertension
    7. Arteriosclerosis
  2. Maximize Refractive Error correction with glasses
  3. Consider dilating drops to improve Vision
  4. Ophthalmology referral for Cataract Extraction
    1. Procedure
      1. Phacoemulsification with intraocular lens replacement
    2. Indications (Refer for impaired function or refractory symptoms)
      1. Impaired Vision
      2. Excessive glare
      3. Poor night Vision
    3. References
      1. Riaz (2006) Cochrane Database Syst Rev (4):CD001323 +PMID:17054134 [PubMed]

IX. Prevention

  1. Avoid excessive UV Light exposure
  2. Smoking Cessation

X. References

  1. Pelletier (2016) Am Fam Physician 94(3):219-26 [PubMed]

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