Cataracts

• Definition: Cataract is the clouding or opacification of the eye’s lens or its capsule, obstructing light passage to the retina.
• Affected Groups: Infants, adults, and older people, predominantly affecting the latter.
  • Present in 70% of patients older than 70 years old
• Characteristics:
  • Can be bilateral and vary in severity.
  • Progresses gradually, initially without impacting daily activities.
  • Typically matures after the fourth or fifth decade, becoming opaque and interfering with routine activities.
• Significance: Major cause of blindness worldwide.
• Risks
  • age
  • smoking
  • lifestyle
  • alcohol
  • sunlight
  • T2DM
• Treatment Options:
  • Early stages: Correction with refractive glasses.
  • Advanced stages: Surgery is recommended and highly effective.

Etiology of Cataracts

• Congenital Cataract: Causes: Maternal nutrition, infections (Rubella, Rubeola), placental hemorrhage.
• Age-Related (Senile) Cataract: Most common type.
• Subcapsular Cataract:
  • Types: Anterior and posterior subcapsular cataracts.
  • Symptoms: Glare, halos, photophobia.
• Nuclear Sclerotic Cataract:
  • Age-related, associated with myopia.
  • Characteristics: Yellowish hue, increased refractive index, potential hypermetropic shift.
• Cortical Cataract:
  • Location: Anterior, posterior, or equatorial cortex.
  • Symptoms: Glare, photophobia.
• Christmas Tree Cataract:
  • Rare, polychromatic needle-like formations.
• Maturity Grading:
  • Immature: Partially opaque lenticular fibers.
  • Mature: Completely opaque lens.
  • Hypermature: Shrunken and wrinkled lens.
  • Morgagnian: Liquefied cortex with sinking nucleus.

Traumatic Cataracts

• Causes:
  • Perforating trauma.
  • Blunt trauma: Flower-shaped opacity.
  • Electric shock: Milky-white opacification, snowflake-like opacities.
  • Ultraviolet and ionizing radiation.
  • Chemical injuries.

Systemic and Endocrine Diseases

• Diabetes Mellitus:
  • Mechanism: Osmotic overhydration from glucose and sorbitol accumulation.
  • Characteristics: Snowflake cortical opacities.
• Myotonic Dystrophy:
  • Symptoms: Iridescent cortical opacities evolving into wedge-shaped and star-like conformation.
• Atopic Dermatitis:
  • Features: Bilateral, rapidly maturing, shield-like anterior subcapsular plaque.
• Neurofibromatosis Type 2:
  • Types: Posterior capsular, cortical, mixed cataracts.
• Hypoparathyroidism/Cretinism.

Secondary Cataracts

• Primary Ocular Pathologies:
  • Chronic anterior uveitis.
  • Acute congestive angle closure.
  • High myopia.
  • Hereditary fundus dystrophies.

Other Causes

• Trauma: Types: Penetrating and blunt trauma, electric shock, infrared radiation, ionizing radiation.
• Drugs: Corticosteroids, anticholinesterase inhibitors, chlorpromazine.
• Nutrition: Deficiency in antioxidants and vitamins.
• Lifestyle: Alcohol use disorder and smoking.

Pathophysiology

• Lens Structure: Made up of cortex (superficial) and nucleus (deeper).
• Mechanisms:
  • Disturbances in lens growth.
  • Fibrous metaplasia of lens epithelium.
  • Cortical hydration between lens fibers.
  • Deposition of urochrome pigment.
• Outcome: Opaque lens behind the pupil, hindering routine activities.

Clinical

• Progressive reduced Vision (usually bilateral)
  • Patients report Clouding or fogging of Vision
  • Myopia may result and may correct Farsightedness
• Skewed Color Perception
  • Blues filtered out
  • Color is shifted to yellow and red part of spectrum
• Diminished Vision in bright light
  • Central opacities block light when pupil constricts
  • Glare with street lights
• Reduced night Vision (with halos in Visual Fields)

Examination findings

• Red reflexes diminished
• Limits view on fundoscopy
• Increase in myopia

Disease-related Complications

• Congenital cataracts: corneal ulcer, corneal perforation (acquired anterior capsular cataract), blindness
• Acquired cataracts: acute congestive glaucoma (Intumescent stage), phacolytic glaucoma, iritis, subluxation of the lens, secondary glaucoma(hypermature stage), blindness

Ophthalmology referral for Cataract Extraction

• Indications (Refer for impaired function or refractory symptoms)
  • Impaired Vision
  • Excessive glare
  • Poor night Vision

• Prevention
  • Avoid excessive UV Light exposure
  • Smoking Cessation

Cataract Referral Criteria for Queensland Health

Eligibility for Referral

1. Visual Acuity:
   • Best corrected visual acuity (BCVA) of 6/12 or worse in the better eye.
   • Significant reduction in visual acuity compared to the patient’s baseline, impacting daily activities.
2. Impact on Quality of Life:
   • Difficulty performing activities of daily living (e.g., reading, driving, recognizing faces).
   • Patient-reported visual disability affecting quality of life or safety.
3. Clinical Findings:
   • Presence of visually significant cataract confirmed on slit-lamp examination.
   • Absence of other ocular pathology that might be the primary cause of visual impairment unless combined surgery is being considered.
4. Symptoms:
   • Significant glare or halo effect, especially impacting night driving.
   • Monocular diplopia (double vision in one eye) or polyopia (seeing multiple images) caused by cataract.

Additional Considerations for Referral

1. Occupational Requirements:
   • Patients whose occupation requires higher visual acuity (e.g., drivers, pilots) may be referred even if visual acuity is slightly better than 6/12.
2. Special Patient Groups:
   • Rapidly progressing cataracts.
   • Patients with other ocular conditions (e.g., diabetic retinopathy, age-related macular degeneration) where cataract surgery might improve management or outcomes of the other condition.
3. Comorbidities:
   • Patients with systemic conditions that may affect the timing or outcome of surgery (e.g., diabetes, hypertension) should be stabilized before referral when possible.

Urgent Referral Criteria

• Rapidly deteriorating vision.
• Cataract causing secondary glaucoma.
• Cataract associated with trauma.
• Cataract causing significant uveitis or other inflammatory conditions.

Advice for Patients with Cataracts Awaiting Surgery

Symptom Management

1. Use of Refractive Glasses:
   • Recommendation: Advise patients to use their current prescription glasses or get a new prescription to optimize vision.
   • Evidence: Improved refractive correction can help manage mild to moderate vision impairment due to cataracts .
2. Sunglasses and Anti-Glare Coatings:
   • Recommendation: Wear sunglasses with UV protection outdoors and consider glasses with anti-glare coatings to reduce glare and improve comfort.
   • Evidence: Sunglasses can reduce photophobia and glare sensitivity, common complaints in cataract patients .
3. Enhanced Lighting:
   • Recommendation: Increase lighting at home and work, especially for tasks like reading and cooking.
   • Evidence: Brighter, directed lighting can help mitigate the effects of reduced visual acuity .

Lifestyle Modifications

1. Fall Prevention:
   • Recommendation: Make home safety modifications to prevent falls, such as removing trip hazards, installing handrails, and ensuring good lighting.
   • Evidence: Cataracts can significantly impair vision, increasing the risk of falls and related injuries .
2. Diet and Hydration:
   • Recommendation: Encourage a balanced diet rich in antioxidants (e.g., vitamins C and E, lutein, and zeaxanthin) and adequate hydration.
   • Evidence: Antioxidants may slow the progression of cataracts, although they cannot reverse the condition .
3. Smoking Cessation and Alcohol Moderation:
   • Recommendation: Advise quitting smoking and limiting alcohol intake.
   • Evidence: Smoking and excessive alcohol consumption are risk factors for cataract progression .

Medication and Other Treatments

1. Avoid Certain Medications:
   • Recommendation: Avoid or discuss the use of medications that may exacerbate cataracts, such as long-term corticosteroids.
   • Evidence: Corticosteroids can increase the risk of posterior subcapsular cataracts .
2. Artificial Tears:
   • Recommendation: Use lubricating eye drops if dry eye symptoms are present.
   • Evidence: Lubricating drops can alleviate discomfort associated with dry eyes, which can be exacerbated by cataracts .

Monitoring and Follow-Up

1. Regular Check-Ups:
   • Recommendation: Schedule regular follow-up appointments to monitor cataract progression and overall eye health.
   • Evidence: Regular monitoring ensures timely intervention if the condition worsens or if new symptoms arise .
2. Report Changes in Vision:
   • Recommendation: Promptly report any significant changes in vision, such as sudden loss of vision, flashes of light, or floaters.
   • Evidence: These symptoms could indicate complications like retinal detachment or other serious conditions that require immediate attention .