Cataract

Question 1

What is cataract?

Answer 1

-Any light scattering opacity within the lens
=If extensive or lying on visual axis it can cause vision loss
=Opacity and cloudiness of lens

Question 2

Types of cataract anatomy

Answer 2

-Cortical
=Peripheral cortical fibres break down
=Spoke-like cataract appearance

-Polar
=Localised, commonly inherited, lie in visual axis

-Posterior subcapsular
=Recently created lens fibres break down, e.g. after X-rays, trauma, or steroids (bilateral)

-Nuclear
=Over time, with oxidative damage and biochemical changes, nuclear fibres cross-link
=Change kens refractive index, common in old age
=Cloudy and brown, greenish tinge

Question 3

Risk factors for cataract

Answer 3

-Age >65, women
-Smoking and alcohol
-Long term UV exposure
-Family history

Question 4

Ocular causes of cataract

Answer 4

-Trauma
-Uveitis
-High myopia
-Steroid eye drops
-Intraocular tumour

Question 5

Systemic causes of cataract

Answer 5

-Diabetes and other metabolic disorders (hypocalcaemia)
-Systemic steroids, chlorpromazine
-X-radiation
-Congenital rubella
-Atopic dermatitis
-Myotonic dystrophy
-Down syndrome

Question 6

Symptoms and signs of cataract

Answer 6

-Painless loss of vision
-Glare and haloes
-Change in refraction, blurring (more difficult for light to reach retina)
-Monocular double vision
-Altered colour perception/ poor colour vision
-↓VA (esp. in bright light)
-Difficulty driving at night
-Defect in red reflex

Question 7

Tests for cataract

Answer 7

-Look for systemic cause in under 60s or if unilateral cataract
-Biometry to enable accurate intraocular lens (IOL) power calculation
-VA, pupillary function, ocular alignment and motility
-Glare vision test
-Slit-lamp examination= visible cataract, normal fundus and optic nerve

Question 8

Management of cataract

Answer 8

-Surgery= phacoemulsification
-Non-surgical= stronger glasses, brighter lighting

Question 9

Complications of cataract surgery

Answer 9

-Iris prolapse
-Posterior capsular opacification (thickening of lens capsule)/ rupture (decreased VA over months)
-Endophthalmitis (vitreal infection)
-Cystoid macular oedema
-Vitreous loss and retinal detachment

Question 10

Pathogenesis of cataract

Answer 10

-The lens is made mostly of water and protein.
-The protein is arranged to let light pass through and focus on the retina.
-Sometimes some of the protein clumps together.
-This can start to cloud small areas of the lens, blocking some light from reaching the retina and interfering with vision

Question 11

Describe phacoemulsification

Answer 11

-Phacoemulsification refers to ultra-sonic method of cataract surgery
-Small-incision cataract surgery with usually no stitches
-Most of the cases are done as day case under LA
-Takes less than half hour

Question 12

PCO treatment

Answer 12

-Posterior Capsular Opacity
-Treated with laser capsulotomy
=The neodymium: YAG laser provides a noninvasive method for discission of the posterior capsule.
=Pulses of laser energy create a small hole in the posterior capsule in the pupillary axis