Cataracts

Question 1

A degenerative change of the lens

• Pathophysiology

Answer 1

• Oxidative damage to the lens
• Breakdown of crystallin proteins
• Proteins partially unfold and aggregate
• Build-up of pigments
• This results in clouding of the lens and optical deterioration

Question 2

Presentation

Answer 2

• Usually bilateral, although may not be symmetrical (more dramatic in 1 than other eye)
• Visual changes
• Reduced visual acuity
• Light scatter
• Sensitivity to glare
• Altered color perception
• Loss of contrast sensitivity
• Image distortion
• Impact
• Difficulty with tasks requiring fine detail
• Mobility difficulties

Question 3

Classification

Answer 3

• By etiology
• Congenital (e.g. intrauterine exposure to rubella, herpes, syphilis)
• Idiopathic
• By clinical appearance/location
• Nuclear, cortical, and posterior subcapsular

Question 4

Risk Factors

• Non-modifiable

Answer 4

• Age (strongest predictor)
• Female gender
• Genetics

Question 5

• Possibly modifiable

risk factors

Answer 5

• UV exposure
• Trauma
• Toxins - tobacco
• Malnutrition – protein deficiency
• Possibly socioeconomic status
• Medications
• Alcohol (heavy use, >2 drinks/day)
• Glucocorticoids (e.g prednisone)
• Antineoplastics (e.g. busulfan, chlorambucil)
• Phenothiazines (e.g. chlorpromazine)
• Thyroid hormone
• Metabolic diseases
• Diabetes
• Obesity
• Chronic hypercalcemic states
• Wilson’s disease

Question 6

Cataracts - Prevention

Answer 6

• Balanced diet rich in nutrients
• Protein, antioxidants
• Protection from UV
• Minimizing ethanol
• Discontinuing tobacco
• Preventing metabolic disease

Question 7

Cataracts – Rationale for

Supplements

Answer 7

Oxidative stress in the retina and lens contribute to degenerative changes
• A number of clinical trials have studied various combinations of
supplements
• Generally studies have enrolled relatively well nourished participants;
some already taking multivitamins.

Question 8

Supplements – Landmark Studies - AREDS

Answer 8

• AREDS (Age Related Eye Disease Study)
• Primary outcomes
• an increase from baseline in nuclear, cortical, or posterior subcapsular
opacity grades or cataract surgery
• at least moderate visual acuity loss from baseline (≥15 letters).

• Results
• N= 4757 participants enrolled
• N=4629 who were aged 55-80y had at least 1 natural lens present
• follow up average of 6.3y
• Outcomes (antioxidants vs placebo)
• Any lens event
• Adjusted OR (CI99) = 1.00 (0.87 – 1.15) (p=0.96)
• Loss of visual acuity
• Adjusted OR (CI99) = 1.07 (0.66 – 1.72) (p=0.73)

antioxidants not helpful

Question 9

Supplements – Landmark Studies

Answer 9

• AREDS2
• Participants were randomly assigned to:
• daily placebo
• lutein/zeaxanthin 10mg/2mg
• omega-3 long-chain PUFA 1 g
• combination
• Outcomes:
• Progression to advanced AMD (primary)
• Cataract surgery (secondary)
• Vision loss (3 or more lines)
• Results (lutein/zeaxanthin vs no lutein/zeaxanthin)
• N= 4203, aged 50-85y, at risk for progression to advanced AMD
• Cataract surgery HR = 0.96 (CI95 0.84-1.10)
• Vision loss HR = 1.03 (CI95 0.93-1.13)

Question 10

Cataracts – Nutrition and Prevention

Answer 10

• “Observational studies do signify the importance of a well balanced
diet, rich with fruit and vegetables, with roughly 150 g of protein per
day and a high intake of vitamin C and E, but low on simple sugars.”
• “In general, the literature suggests diets high in fruit and vegetables,
Vitamin C, zeaxanthin, lutein and multivitamin-mineral supplements
are associated with lower disease rates, while supplemental forms of
selenium and Vitamin E had little effect.”
• Bottom line: vitamin supplements are not recommended for
prevention or treatment of cataracts

Question 11

Surgery

Answer 11

• Concomitant medication
• Dilator (e.g. phenylephrine)
• Local anaesthetic
• Sedative (if needed)
• Hold medications
• Anticoagulants (sometimes)
• High risk medications
• Alpha-antagonists (floppy iris)

• Follow-up
• Anti-inflammatory (NSAID), steroid eye
drop
• Antibiotic eye drops