Cataract

para>Some degree of cataract formation is expected in all people >70 years of age. �
Pediatric Considerations

See "Congenital Cataract"�; may present as leukocoria.

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Pregnancy Considerations

See "Congenital Cataract"� (i.e., medications, metabolic dysfunction, intrauterine infection, and malnutrition).

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EPIDEMIOLOGY

Incidence

~48% of the 37 million cases of blindness worldwide result from cataracts (1,2).
Leading cause of treatable blindness and vision loss in developing countries (1,2)
Predominant age: depends on type of cataract
Predominant sex: male > female

Prevalence

Cataract type and prevalence are highly variable based on population demographic.
An estimated 50% of people 65 to 74 years of age and 70% of people >75 years of age have age-related cataract.

ETIOLOGY AND PATHOPHYSIOLOGY

Age-related cataract:
- Continual addition of layers of lens fibers throughout life creates hard, dehydrated lens nucleus that impairs vision (nuclear cataract).
- Aging alters biochemical and osmotic balance required for lens clarity; outer lens layers hydrate and become opaque, adversely affecting vision.
Congenital:
- Usually unknown etiology
- Drugs (corticosteroids in 1st trimester, sulfonamides)
- Metabolic (diabetes in mother, galactosemia in fetus)
- Intrauterine infection during 1st trimester (e.g., rubella, herpes, mumps)
- Maternal malnutrition
Other cataract types:
- Common feature is a biochemical/osmotic imbalance that disrupts lens clarity.
- Local changes in lens protein distribution lead to light scattering (lens opacity).

Genetics

Congenital (e.g., chromosomal disorders [Down syndrome])
Genetics of age-related cataract are not yet established but likely multifactorial contribution.

RISK FACTORS

Aging
Cigarette smoking
Ultraviolet (UV) sunlight exposure
Diabetes
Prolonged high-dose steroids
Positive family history
Alcohol

GENERAL PREVENTION

Use of UV protective glasses
Avoidance of tobacco products
Effective control of diabetes
Care with high-dose, long-term steroid use (systemic therapy > inhaled treatment)
Protective methods using pharmaceutical intervention (e.g., antioxidants, acetylsalicylic acid [ASA], hormone replacement therapy [HRT]) show no proven benefit to date.

COMMONLY ASSOCIATED CONDITIONS

Diabetes (especially with poor glucose control)
Myotonic dystrophy (90% of patients develop visually innocuous change in 3rd decade; becomes disabling in 5th decade)
Atopic dermatitis (AD) (10% of patients with severe AD develop cataracts in 2nd to 4th decades, often bilateral)
Neurofibromatosis type 2
Associated ocular disease or "secondary cataract"� (e.g., chronic anterior uveitis, acute [or repetitive] angle-closure glaucoma or high myopia)
Drug induced (e.g., steroids, chlorpromazine)
Trauma

DIAGNOSIS

HISTORY

Age-related cataract:
- Decreased visual acuity, blurred vision, distortion, or "ghosting"� of images (1,2)
- Problems with visual acuity in any lighting condition
- Falls or accidents; injuries (e.g., hip fracture)
Congenital: often asymptomatic, leukocoria, parents notice child's visual inattention or strabismus
Other types of cataract:
- May also present with decreased visual acuity
- Appropriate clinical history or signs to help with diagnosis

PHYSICAL EXAM

Visual acuity assessment for all cataracts
Age-related cataract: lens opacity on eye examination
Congenital:
- Lens opacity present at birth or within 3 months of birth
- Leukocoria (white pupil), strabismus, nystagmus, signs of associated syndrome (as with Down or rubella syndrome)
- 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 associated with characteristic physical findings (e.g., metabolic, trauma)

DIFFERENTIAL DIAGNOSIS

An opaque-appearing eye may be due to opacities of the cornea (e.g., scarring, edema, calcification), lens opacities, tumor, or retinal detachment. Biomicroscopic examination (slit lamp) or careful ophthalmoscopic exam should provide diagnosis.
In the elderly, visual impairment is often due to multiple factors such as cataract and macular degeneration, both contributing to visual loss.
Age-related cataract is significant if symptoms and ophthalmic exam support cataract as a major cause of vision impairment.
Congenital lens opacity in the absence of other ocular pathology may cause severe amblyopia.
Note: Cataract does not produce a relative afferent pupillary reaction defect. Abnormal pupillary reactions mandate further evaluation for other pathology.

DIAGNOSTIC TESTS & INTERPRETATION

Visual quality assessment: Glare testing, contrast sensitivity is sometimes indicated.
Retinal/macular function assessment: potential acuity meter testing
Workup of underlying process

Test Interpretation
Consistent with lens changes found in the type of cataract; however, diagnosis is made by clinical examination. �

TREATMENT

Outpatient (usually)
~1.64 million cataract extractions in the United States yearly (3,4)

GENERAL MEASURES

Eye protection from UV light �

MEDICATION

There are currently no medications to prevent or slow the progression of cataracts. �

ISSUES FOR REFERRAL

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

SURGERY/OTHER PROCEDURES

Age-related cataract:
- Surgical removal is indicated if visual impairment-producing symptoms are distressing to the patient, interfering with lifestyle or occupation, or posing a risk for fall or injury (3,4)[A].
- Because significant cataract may develop gradually, the patient may not be aware of how it has changed his or her lifestyle. Physician may note a significant cataract, and patient reports "no problems."� Thus, evaluation requires effective physician-patient exchange of information.
- Surgical technique: Cataract extraction via small incisions, followed by implantation of a prosthetic intraocular lens; lenses have power calculated based on size of the eye and curvature of cornea usually to correct for distance vision; surgery performed on one (worse) eye, with contralateral surgery only after recovery and if deemed necessary; generally takes <1 hour depending on surgical technique
- Anesthesia: usually regional injection or topical with sedation and monitoring of vital signs
- Preoperative evaluation: by the primary care physician:
  - Patients on anticoagulants may need to be temporarily discontinued 1 to 2 weeks before surgery if possible (but not always necessary; thus, need to discuss with ophthalmologist).
  - Patients who have ever taken an α-blocker such as tamsulosin (Flomax) should alert their ophthalmologist (increased risk of intraoperative floppy iris syndrome [IFIS] even in patients who no longer use these drugs).
- Postoperative care: usually protective eye shield as directed, topical antibiotic, NSAIDs, and steroid ophthalmic medications; avoid lifting or bending over for a few weeks.
Congenital cataract:
- Treatment is surgical removal of cataract. Newborns may require surgery within days to reduce risk of severe amblyopia. Use of lens implants is controversial because the eyes are growing.
- Postoperative care: long-term patching program for good eye to combat amblyopia; refractive correction of operative eye, with multiple repeat examinations; challenging for physician and parents

ONGOING CARE

FOLLOW-UP RECOMMENDATIONS

Patient Monitoring

As cataract progresses, an ophthalmologist may change spectacle correction to maintain vision. When this is no longer successful and interferes with patient's activities of daily living, surgery is indicated.
Following surgery, spectacle correction may be required to maximize near and/or far visual acuity. Refraction is usually prescribed several weeks after surgery.

PATIENT EDUCATION

Medline Plus on cataracts at: https://www.nlm.nih.gov/medlineplus/cataract.html �

PROGNOSIS

Ocular prognosis is good after cataract removal if no prior or coexisting ocular disease: 94.3% of otherwise healthy eyes achieve best corrected visual acuity of 20/40 or better. Success rates are lower with comorbidities such as diabetes and glaucoma (5).
In congenital cataracts, prognosis often is poorer because of the high risk of amblyopia.

COMPLICATIONS

Vary widely from delay in visual recovery or protracted visual discomfort to blindness and loss of eye
Nearly all reported complications occur rarely (<2% of eyes) except for posterior capsule opacification (14.7-42.7% of eyes, usually treated with Nd-YAG laser capsulotomy in office with a rate of 4-25.3%) (6,7)[B].
Poor preoperative visual acuity is related to surgical complications (8).

REFERENCES

11 Asbell �PA, Dualan �I, Mindel �J, et al. Age-related cataract. Lancet. 2005;365(9459):599-609.22 Abraham �AG, Condon �NG, West Gower �E. The new epidemiology of cataract. Ophthalmol Clin North Am. 2006;19(4):415-425.33 Riaz �Y, Mehta �JS, Wormald �R, et al. Surgical interventions for age-related cataract. Cochrane Database Syst Rev. 2006;(4):CD001323.44 Fedorowicz �Z, Lawrence �D, Gutierrez �P. Day care versus in-patient surgery for age-related cataract. Cochrane Database Syst Rev. 2005;(1):CD004242.55 Biber �JM, Sandoval �HP, Trivedi �RH, et al. Comparison of the incidence and visual significance of posterior capsule opacification between multifocal spherical, monofocal spherical, and monofocal aspheric intraocular lenses. J Cataract Refract Surg. 2009;35(7):1234-1238.66 Findl �O, Buehl �W, Bauer �P, et al. Interventions for preventing posterior capsule opacification. Cochrane Database Syst Rev. 2010;(2):CD003738.77 Lundstr �m �M, Barry �P, Henry �Y, et al. Visual outcome of cataract surgery; study from the European Registry of Quality Outcomes for Cataract and Refractive Surgery. J Cataract Refract Surg. 2013;39(5):673-679.88 Lundstr �m �M, Goh �PP, Henry �Y, et al. The changing pattern of cataract surgery indications: a 5-year study of 2 cataract surgery databases. Ophthalmology. 2015;122(1):31-38.

CODES

ICD10

H26.9 Unspecified cataract
H25.9 Unspecified age-related cataract
Q12.0 Congenital cataract
H26.40 Unspecified secondary cataract
H26.32 Drug-induced cataract, left eye
H26.491 Other secondary cataract, right eye
H26.31 Drug-induced cataract, right eye
H26.33 Drug-induced cataract, bilateral
H26.493 Other secondary cataract, bilateral
H26.499 Other secondary cataract, unspecified eye
H26.492 Other secondary cataract, left eye
H26.103 Unspecified traumatic cataract, bilateral
H26.102 Unspecified traumatic cataract, left eye
H26.30 Drug-induced cataract, unspecified eye
H26.109 Unspecified traumatic cataract, unspecified eye
H26.101 Unspecified traumatic cataract, right eye

ICD9

366.9 Unspecified cataract
366.10 Senile cataract, unspecified
743.30 Congenital cataract, unspecified
366.50 After-cataract, unspecified
366.20 Traumatic cataract, unspecified
366.45 Toxic cataract
366.53 After-cataract, obscuring vision
366.52 Other after-cataract, not obscuring vision

SNOMED

193570009 Cataract (disorder)
39450006 Senile cataract
79410001 congenital cataract (disorder)
47337003 after-cataract (disorder)
34361001 traumatic cataract (disorder)
38583007 Toxic cataract

CLINICAL PEARLS

Cataracts are the leading cause of blindness worldwide; 90% are age-related.
Primary indication for cataract surgery is visual impairment leading to significant lifestyle changes for the patient.
For congenital cataracts, must always rule out ocular tumor because early diagnosis and treatment of retinoblastoma may be lifesaving.
Before prescribing an α-blocker for an older adult with hypertension or a prostate or urinary retention problem, consider whether the patient has cataracts (due to increased risk of IFIS).

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