Cataract Disease

BASICS

DESCRIPTION

Any opacity of the lens, either localized or generalized. Single largest cause of blindness in the world, blinding an estimated 17 million people.

Types include:
- Age-related ("senile") - over 90%
- Congenital - 1/250 newborns, 10-38% of childhood blindness
- Toxic/nutritional
- Systemic disease associated e.g., myotonic dystrophy, atopic dermatitis
- Metabolic - diabetes (accelerated sorbitol pathway), hypocalcemia, Wilson's disease
- "Complicated" - secondary to associated eye disease, e.g., uveitis (juvenile rheumatoid arthritis, sarcoid, etc.). Also secondary to occult tumor (melanoma, retinoblastoma).
- Trauma - heat (infrared), electrical shock, radiation, concussion, perforating eye injuries, intraocular foreign body
System(s) affected: Nervous
Genetics:
- Age related cataract has no clear pattern
- Congenital sometimes associated, e.g., heredofamilial systemic disorders (Laurence-Moon-Biedl syndrome), chromosomal disorders (Down syndrome)
Incidence/Prevalence in USA:
- 5% of age 52-62
- 46% of age 75-85 have significant vision loss (20/30 or worse)
- 92% of age 75-85 have some cataract changes
Predominant age: Depends on type of cataract
Predominant sex: Male = Female

SIGNS AND SYMPTOMS

Age-related cataract:
- Blurred vision, distortion or "ghosting" of images
- Problems with visual acuity in bright light or night driving (glare)
- Falls or accidents
- Injuries (e.g., hip fracture)
- Signs on eye examination: A lens opacity consistent with the symptoms
Congenital:
- Lens opacity present at birth or within three months after birth
Often asymptomatic or parents notice child's visual inattention or strabismus (lazy eye)
- Leukocoria (white pupil reflex), strabismus, nystagmus, associated syndrome signs (as in Down or rubella syndromes)
- Visual acuity tests abnormal for one or both eyes
- Note: Must always rule out ocular tumor. Early diagnosis and treatment of retinoblastoma may be lifesaving.
Other types of cataract:
- May present with decreased visual acuity complaint
- Appropriate history or signs to help in diagnosis

CAUSES

Age-related cataract:
- Continual addition of layers of lens fibers throughout life creates hard, dehydrated lens nucleus which impairs vision (nuclear cataract)
- Aging alters biochemical and osmotic balance required for lens clarity, outer lens layers hydrate and become opaque, affecting vision
Congenital:
- Usually obscure
- Drugs (corticosteroids in first trimester, sulfonamides, etc.)
- Metabolic - diabetes in mother, galactosemia in fetus
- Intrauterine infection - first trimester (rubella, herpes, mumps)
- Maternal malnutrition
Other cataract types:
- Have in common that a biochemical/osmotic imbalance disrupts lens clarity
- Local changes in lens protein distribution lead to light scattering manifest as lens opacity

RISK FACTORS

Aging
Patient with one of the predisposing diseases

DIAGNOSIS

LABORATORY

N/A
Drugs that may alter lab results: N/A
Disorders that may alter lab results: N/A

PATHOLOGICAL FINDINGS

Consistent with lens changes found in the type of cataract

SPECIAL TESTS

Visual quality assessment: Glare testing, contrast sensitivity are sometimes indicated. (Hyperglycemic state as in poor diabetic control creates osmotic change within lens and may alter measurement of visual acuity and refractive state.)
Retinal/macular function assessment: Potential acuity meter testing, fluorescein retinal angiography sometimes required

IMAGING

N/A

DIAGNOSTIC PROCEDURES

Noted above in special testing

TREATMENT

APPROPRIATE HEALTH CARE

Outpatient or inpatient surgery

GENERAL MEASURES

Age-related cataract
- Since significant cataract may develop gradually, patient may not be aware of how it has changed his/her lifestyle. Physician may note a significant cataract and patient reports "no problems." Thus the evaluation requires physician/patient exchange of information.
- Pre-surgical evaluation - by the primary care physician includes physical exam, lab work (CBC, electrolytes, ECG). Patients on anticoagulants may need to temporarily discontinue one week before surgery if possible. Not always necessary, so need to discuss with ophthalmologist.

SURGICAL MEASURES

Age-related cataract:
- Surgical removal of the cataract - indicated if visual impairment producing symptoms distressing to the patient, or interfering with lifestyle or occupation, or posing risk of fall or injury
- Since significant cataract may develop gradually, patient may not be aware of how it has changed his/her lifestyle. Physician may note a significant cataract and patient reports "no problems." Thus the evaluation requires physician/patient exchange of information.
- Surgical technique - cataracts are not removed by laser. Most surgical techniques include implantation of a plastic intraocular lens immediately following cataract extraction.
- Anesthesia - usually local, with anesthesiologist monitoring vital signs
- Pre-surgical evaluation - by the primary care physician includes physical exam, lab work (CBC, electrolytes, ECG). Patients on anticoagulants may need to temporarily discontinue one week before surgery if possible. Not always necessary, so need to discuss with ophthalmologist.
- Postoperative care - usually protective eye shield as directed, topical antibiotic and steroid ophthalmic medications. Avoid lifting, bending over for a few weeks.
Congenital cataract
- Treatment is surgical removal of cataract. Newborn may need surgery within days to reduce risk of severe amblyopia. Use of implant lenses controversial.
- Postoperative care - long-term patching program for good eye to combat amblyopia. Refractive correction of operative eye, with multiple repeat examinations. Very difficult challenge for physician and parents.

ACTIVITY

See above

DIET

N/A

PATIENT EDUCATION

See above

FOLLOW UP

PREVENTION/AVOIDANCE

Use of ultraviolet protecting glasses in sunny climates may slow progression of cataract, but this is not proven by controlled studies to date
Antioxidants (vitamins C, E, etc.) theoretically beneficial, but not proven

POSSIBLE COMPLICATIONS

Blindness

EXPECTED COURSE AND PROGNOSIS

Ocular prognosis good after cataract removal if no prior ocular disease.
In congenital cataracts prognosis is often poor because of the high risk of amblyopia.

MISCELLANEOUS

ASSOCIATED CONDITIONS

Diabetes
Ocular diseases

AGE-RELATED FACTORS

Pediatric: See information on congenital cataracts
Geriatric: 92% of people over age 75 have cataracts
Others: N/A

PREGNANCY

See information on congenital cataracts (e.g., rubella syndrome)

OTHER NOTES

If patient has cataract and symptoms do not seem to support recommended surgery, a second opinion by another ophthalmologist may be indicated

ABBREVIATIONS

N/A

Clinical Investigations

ROLE OF HOMOEOPATHY

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