Adult cataract

Question 1

Define adult cataract.

Answer 1

A condition characterized by the discoloration or the clouding of the ocular lens which causes the decline in vision and eventually lead to blindness if left untreated

Question 2

Explain the pathophysiology of cataract. (2)

Answer 2

-Ageing causes lens protein changes, this causes fluctuations in the refractive index of the lens, scatter light rays and reduce transparency.

-Trauma directly compromise the lens capsule that leads to cortical opacification at the site of injury

Question 3

How are cataracts classified? (4)

Answer 3

By morphology- nuclear, cortical, subcapsular
By etiology- traumatic, diabetic, drug induced
By age group- Congenital, juvenile, senile
By stages of maturity- Immature, mature, hyper mature

Question 4

Define subscapular, nuclear and cortical cataracts.

Answer 4

Subcapsular cataract- It manifests directly under the lens capsule and it is classified into anterior and posterior. In anterior the cataract lies directly under the lens capsule. In posterior, the cataract forms on the backside of the lens. It’s caused by ageing, diabetes, steroid use and trauma.

Nuclear cataract- It affects the center of the lens and the central area of the lens hardens and turns brown or yellow. It eventually spreads to other areas of the lens. It’s often caused by aging.

Cortical cataract- The cataracts form from the edges and spread towards the center, forming a wedge shaped opacity. It’s commonly caused by diabetes and aging.

Question 5

What is meant by ‘second sight’ of the aged?

Answer 5

Nuclear cataract is often associated with myopia due to an increase in the refractive index of the nucleus, resulting in some elderly patients being able to read without spectacles again (‘second sight of the aged’); in contrast, in the healthy ageing eye (and in occasional cases of cortical and subcapsular cataract) there is mild hypermetropic shift

Question 6

Define congenital, secondary, traumatic cataract and cataract secondary to systemic diseases.

Answer 6

Congenital cataract- They are present at birth or form during the during the babies’ first year. They maybe caused by TORCH infections, disorders of metabolism or hereditary syndromes

Secondary cataract- Develops as a result of other primary ocular diseases like chronic anterior uveitis and acute congestive angle glaucoma.

Traumatic cataract- Most common cause of unilateral cataract in the youth. Blunt trauma, penetrating trauma, radiation, electric shock can all result in cataract.

Cataract secondary to systemic diseases- Systemic diseases like DM or hypertension can also cause cataract

Question 7

Define immature, mature, hyper mature and Morgagnian catarcats.

Answer 7

Immature cataract
-Early stages of cataract progression and the lens is partially o opaque
-Red reflex is still present allowing the retinal visualization

Mature cataract
-Advanced stage in cataract progression
-The lens are completely opaque with absent red reflex
-White-yellow lens discoloration with only light perception

Hypermature cataract
-End stage of cataract progression
a shrunken and wrinkled anterior capsule

Morgagnian
-Hyper mature cataract in which liquefaction of the cortex has allowed the nucleus to sink inferiorly

Question 8

Give non-modifiable risk factors for cataract.

Answer 8

Old age
Family history
Female gender

Question 9

Give 6 modifiable risk factors for cataract.

Answer 9

Diabetes mellitus
Hypertension
Excessive exposure to sunlight
Smoking
Obesity
Excessive alcohol drinking
Previous eye injury or inflammation
Previous eye surgery
Prolonged use of corticosteroid medication

Question 10

Give 5 clinical features of cataract.

Answer 10

-Reduced visual acuity
-Clouded, blurred or dim vision
-Seeing halos around lights
-Change perception of colours
-Double vision in a single eye
-Difficulties with vision at night
-Decreased sensitivity to bright light and glare to on coming head lights

Question 11

Give 4 differential diagnosis for cataract.

Answer 11

-Glaucoma
-Refractive errors like myopia, hyperopia, astigmatisation
-Macular degeneration
-Diabetic retinopathy
-Corneal dystrophy and degeneration
-Optic atrophy
-Retinitis pigmentosa

Question 12

Name 3 investigations used in cataract.

Answer 12

• Ophthalmoscopy
• Slit lamp examination
• Ultrasound scan(B scan)
• Visual acuity testing

Question 13

What is the definitive treatment for cataract?

Answer 13

Surgery

Question 14

Give 2 complications of cataract.

Answer 14

Glaucoma, Deprivation amblyopia