Diagnosis → Ophthalmology

Cataract

Etiology

Causes [vcm]

• Senile cataract: The most common type

• Congenital: Related to maternal nutrition, Rubella, Rubeola, placental hemorrhage

• Subcapsular cataract: Fibrous metaplasia of the lens epithelium

• Nuclear sclerotic cataract: Associated with myopia and aging

• Cortical cataract: Cortical opacities

• Christmas tree cataract: Polychromatic needle-like formation in the cortex/nucleus

• Traumatic

  • Perforating trauma

  • Blunt trauma

  • Electric shock

  • Ultraviolet radiation

  • Ionizing radiation

  • Chemical injuries

• Systemic diseases

  • Diabetes mellitus

  • Myotonic dystrophy

  • Atopic dermatitis

  • Neurofibromatosis type 2

  • Hypoparathyroidism or Cretinism

• Secondary cataract: Result from other primary ocular pathology

  • Iridocyclitis (anterior uveitis)

  • Acute congestive angle closure glaucoma

  • High myopia

  • Hereditary fundus dystrophies

  • Drugs: Corticosteroids, Anticholinesterase inhibitors, and Chlorpromazine

  • Poor nutrition: Antioxidant and vitamin deficiency

  • Alcohol and Smoking

Pathophysiology [vcm]

1. The lens consists of two main parts:

   • Cortex (superficial part) - containing younger fibers

   • Nucleus (deeper part) - containing older fibers

2. Chronic lens stress/injury/inflammation --> degenerative processes

3. Lens protein/fiber/hydration changes --> loss of transparency and light scatter

4. Symptoms:

   • Blurry vision / blindness

   • Monocular diplopia or polyopia

   • Colored rainbow halos around the light

   • Sensitivity to glare / photophobia

   • Frequently changing refractive glasses

   • Disturbance in color vision (yellowing of objects)

   • Reduced contrast

   • Reduced night vision

Risk factors [oec]

• Increasing age

• Diabetes mellitus

• Corticosteroid exposure

• Smoking

• UV-B exposure

• Ocular trauma;

• Uveitis/ocular inflammation

• Genetic predisposition; retinitis pigmentosa; congenital rubella; Down syndrome

Complications [vcm]

• Corneal ulcer

• Corneal perforation (acquired anterior capsular cataract)

• Blindness

• Glaucoma

• Iritis

• Subluxation of the lens

• Surgery-related complications: uveitis, posterior capsular thickening/rupture, aphakia, after cataract, growth-related refractive changes, glaucoma, retinal detachment, hyphaema, corneal burn, iris prolapse, endophthalmitis, cystoid macular edema, dysphotopsia, ptosis

Epidemiology

Prevalence per 100.000 [vws]

Default

Approach

• Ophthalmic examination: [vcm]

  • Decreased visual acuity

  • Defect in pupillary response

  • No fundal view due to dark opacity in the center

• Slit lamp examination:

  • Opacity with clear areas of lens matter

• Fundus evaluation to rule out age-related macular degeneration, macular scar

• Ultrasound to rule out retinal detachment and posterior staphyloma

Diagnostic criteria

• Lens opacity on slit lamp and

• Visual function limitation consistent with cataract and

• No better explanation (other ocular comorbidities)

Treatment

Management of contributing systemic conditions [vcm]

• Diabetes mellitus

• Hypertension

• Stroke

• Uveitis

• Diabetic macular edema

• Corticosteroid alternatives

Congenital Cataract [vcm]

1. Medical: If visual acuity is 6/24 or better

   • Refractive glasses

   • Pupillary dilatation with 2.5% phenylephrine, cyclopentolate and atropine

2. Surgery: If visual acuity is worse than 6/24

   • Irrigation and aspiration of the lens

   • + Intraocular lens implantation

   • + Anterior vitrectomy + primary posterior capsulotomy

Senile Cataract [vcm]

1. Medical: No medical treatment is effective

2. Surgery:

   • Extracapsular cataract extraction

   • Intracapsular cataract extraction: an old technique not used frequently due to complications

   • Phaco-emulsification: a modification of extracapsular cataract extraction

   • Laser phacolysis

Differential diagnoses

Age-related macular degeneration, Corneal ulcer, Glaucoma, Iridocyclitis, Keratoconjunctivitis sicca, Optic neuritis, Retinal artery occlusion, Retinal detachment, Retinitis, Retinopathy