BASICS

DESCRIPTION

Any opacity of the lens.

EPIDEMIOLOGY

Incidence

• Most common cause of blindness in the world

• Account for approximately 50% of low-vision cases in adults over age 40 in the USA

• Number of individuals with cataracts in the USA will increase by 50% by 2020.

Prevalence

• Some evidence of lens opacity found in 96% of those over 60 years of age

• Visually significant cataracts in 5% at age 65 and 50% for persons older than 75 in the USA

RISK FACTORS

• Exposure to higher intensity of incident or reflected ultraviolet light especially ultraviolet-B (UV-B)

• High-energy radiation

• Exposure to high levels of oxygen

• Smoking and tobacco chewing

Genetics

• Family history is a risk factor for aging-related cataracts.

• Specific genes have not been identified.

GENERAL PREVENTION

• Smoking cessation

• Brimmed hats and UV-B blocking sunglasses

• No recommendations for the use of nutritional supplements to prevent or delay cataract progression can be made at this time

• Use of alternate medication in patients taking long-term inhaled or oral corticosteroids

• Behavior modification to reduce risk of developing type 2 diabetes

PATHOPHYSIOLOGY

• Anatomic location:

– Nuclear

– Cortical

– Posterior subcapsular

– Mixed

– Other:

Capsular (polar)

Anterior subcapsular

Lens epithelial decompensation

Retrodots

Advanced

• Studies have shown that cataracts progress over time.

ETIOLOGY

• Age related—Most common

• Congenital and juvenile:

– Part of systemic syndrome

– Isolated

– AD

– AR

– X-linked

• Traumatic

• Associated with primary ocular disease:

– Uveitis

– Glaucoma

– Retinal detachment

– Retinal degeneration

– Sclerocornea

– Microphthalmos

– Intraocular tumor

– Norrie’s disease

– Persistent hyperplastic primary vitreous (PHPV)

– Retinopathy of prematurity

– Aniridia

– High myopia

• Associated with systemic disease:

– Metabolic disorders:

– Diabetes

– Galactosemia

– Hypoparathyroidism/hypocalcemia

– Lowe’s syndrome

– Wilson’s disease

– Renal disease:

– Alport’s disease

– Cutaneous disease:

– Atopic dermatitis

– Connective tissue/skeletal disorders:

– Myotonic dystrophy

– Marfan’s syndrome

– Central nervous system:

– Bilateral acoustic neuroma

– Down’s syndrome

• Environmental exposure:

– Ionizing radiation:

– X-ray

– Ultraviolet

– Infrared

– Microwave

– Pharmaceuticals:

– Steroids

– Miotics

– Antipsychotics (e.g., phenothiazines)

– Electric

– Infectious:

– Rubella

– Postsurgical:

Glaucoma

Pars plana vitrectomy

• Other:

– Ectopic lentis

– Lenticonus and lentiglobus

DIAGNOSIS

HISTORY

• Progressive visual loss affecting one or both eyes

• Emphasize functional difficulties related to the patient’s activities of daily living

• Glare and reduced color perception

• Type of cataract determines symptoms.

• Medications—Flomax or other alpha-1 blockers associated with intraoperative floppy iris syndrome

• Systemic diseases

• Trauma

• Other ocular disease affecting vision

• Visual function prior to cataract development

PHYSICAL EXAM

• Complete ocular exam:

– Distance and near vision

– Pupillary examination

– Refraction to obtain best corrected visual acuity

– Measurement of intraocular pressure

– Fundus exam concentrating on macula

• Slit lamp exam:

– Cornea:

– Clarity or localized opacities

– Endothelial function—guttata

– Anterior chamber depth

– Iris:

– Pupillary dilation

– Posterior synechiae

– Cataract types:

– Nuclear

– Posterior subcapsular

– Cortical

– Abnormalities of lens position

– Zonular instability—phacodonesis

– Pseudoexfoliation

DIAGNOSTIC TESTS & INTERPRETATION

Lab

Glare testing in patients with glare complaint and good visual acuity (1)[A]

Imaging

Initial approach

• B-scan ultrasonography if fundus obscured to rule out posterior segment disease

• A-scan or laser partial coherence optical biometry measurement of axial length

• Endothelial cell count or pachymetry if endothelial disease present

• Keratometry readings

• Corneal topography

• Fluorescein angiography

• Optical coherence tomography may be helpful to diagnose subtle macular pathology.

Follow-up & special considerations

• Latest generation lens calculation formulas should be used in the intraocular lens (IOL) selection process.

TREATMENT

MEDICATION

Mydriasis may be used successfully in some patients if they desire nonsurgical treatment or are not surgical candidates.

ADDITIONAL TREATMENT

General Measures

Correct refractive error if surgery not indicated

SURGERY/OTHER PROCEDURES

• Surgical indications:

– To improve visual function

– Surgical therapy for ocular disease (lens-related glaucoma or uveitis)

– To aid with management of ocular disease

– Extracapsular cataract extraction most commonly by phacoemulsification (ultrasonic technique) is a preferred method to remove a cataract

• Anesthesia techniques:

– General

– Local (regional):

Retrobulbar

Peribulbar

Sub-Tenon’s

Topical with or without intracameral

• Technical elements of successful cataract procedure:

– Temporal, appropriately sized clear-corneal incision with sutureless architecture

– Use of an ophthalmic viscosurgical device (OVD) to provide protection of corneal endothelium, manipulate tissue, and maintain working space

– Continuous circular capsulorrhexis sized to overlap the IOL edge

– Hydrodissection of lens

– Nuclear disassembly and emulsification technique for lens removal

– Irrigation and aspiration of remaining cortex

– Capsular bag fixation of the foldable posterior chamber IOL

– Removal of the OVD to minimize postoperative IOP elevation

– Assurance of watertight incision using sutures if necessary

• Recent IOL developments:

– Aspheric optic IOLs improve functional vision and quality of vision by improving contrast sensitivity, decreasing haloes, and improving optical quality.

– Toric IOLs reduce spectacle dependence in patients with corneal astigmatism.

– Monovision and presbyopia-correcting IOLs are strategies used to reduce spectacle dependence after cataract surgery—patient selection critical.

– Presbyopia-correcting IOLs:

Multifocal

Accommodative

IN-PATIENT CONSIDERATIONS

• Nearly all cataract surgery is performed in an outpatient setting either in a hospital-based outpatient surgical facility or in a freestanding ambulatory surgery center.

• Inpatient surgery may be necessary if the need arises for complex ocular care, multiple procedures, and general medical and nursing care, or if there are multiple ocular conditions.

ONGOING CARE

FOLLOW-UP RECOMMENDATIONS

• Use of 5% solution of povidone iodine in the conjunctival sac prior to surgery has been proven to reduce risk of endophthalmitis (2)[A]

• Postoperative regimens of topical antibiotics, corticosteroids, and NSAIDs vary from surgeon to surgeon.

Patient Monitoring

• First postoperative exam within 24–48 h

• Final refractive visit between 1 and 4 weeks after small-incision surgery and 6–12 weeks after sutured large-incision cataract surgery

• Posterior capsule opacification (PCO) incidence varies but may be up to 50% by 2 years post surgery.

– Nd:Yag laser capsulotomy effective in restoring visual function in patients with significant PCO

PROGNOSIS

• Cataract surgery has been shown to have a significant positive impact on vision-dependent function and health-related quality of life.

• Reduced risk of falls and hip fractures following cataract surgery

• 85–90% of all patients achieve 20/40 or better best-corrected visual acuity after surgery.

• 95% without ocular comorbidities achieve 20/40 or better visual acuity.

• Ocular comorbidities that may affect outcome of surgery:

– Amblyopia

– AMD

– Diabetic retinopathy

– Fuch’s corneal dystrophy

– Glaucoma

– Pseudoexfoliation syndrome

– Uveitis

• High-risk ocular characteristics that increase risk of surgical complication:

– Previous eye surgery:

– Prior refractive surgery alters corneal curvature and makes IOL calculation difficult (3)[A].

– Very long (high myopia) and very short eyes

– Small pupils or eyes with posterior synechiae

– Scarred or cloudy corneas

– Zonular weakness

– Prior ocular trauma

– Systemic use of alpha-1A adrenergic antagonists (Flowmax)

COMPLICATIONS

• PCO most common event post surgery

• Sight threatening complications:

– Endophthalmitis

– Suprachoroidal hemorrhage

– Cystoid macular edema

– Retinal detachment

– Corneal edema

– IOL dislocation

• Intraoperative events:

– Posterior capsule rupture

– Vitreous loss

• Complications of IOLs:

– Incorrect power

– IOL malposition

– Uveitis–glaucoma–hyphema syndrome

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