Cataracts and glaucoma

Question 1

what is cataracts?

Answer 1

Lens of eye gradually becomes cloudy

Question 2

What are the causes of cataracts?

Answer 2

Most commonly a normal aging process.
Other causes: smoking, increased alcohol consumptions, trauma, diabetes, long term corticosteroids, radiation exposure, myotonic dystrophy and metabolic disorders like HYPOCALCAEMIA

Question 3

Presentation of cataracts?

Answer 3

Reduced vision,
Faded colour vision,
Glare (lights brighter than normal)
Halos around lights,
Defect in red reflex.

Question 4

Investigations for cataracts?

Answer 4

Ophthalmoscopy - done after pupil dilation. It will show normal fundus and optic nerve.
Slit lamp examination - visible cataract

Question 5

Classification of cataracts?

Answer 5

Nuclear - change lens refractive index.
Polar - localized, commonly inherited in visual axis.
Subcapsular - due to steroids. just deep to the lens capsule.
Dot opacities - common in normal lenses

Question 6

Management of cataracts?

Answer 6

Non surgical - early stages managed conservatively with stronger glasses and encourage bright lights (prevents mydriasis which worsens glare). However will not fix it

Surgery - Lens replacement. Referral for surgery dependant on whether visual impairment is present, imact on QOL and patient choice.

Question 7

Complications following cataracts surgery?

Answer 7

Posterior capsule opacification (thickening of lens capsule)
Retinal detachment,
Posterior capsule rupture,
Endophthalmitis (inflammation of aqueous and/or vitrous humour).

Question 7

What is open angle glaucoma vs closed angle?

Answer 7

Open - iris is not covering trabecular network so there is still some drainage of aqeuous humour but not as much so IOP still high.
Closed - Trabecular network completely closed so no drainage of aqeuous humour. Emergency.

Question 8

Risk factors for open angle glaucoma?

Answer 8

Increasing age
Genetics
Afro-carribean.
Myopia (ojects close are clear but far away are blurry),
HTN,
Diabetes,
Corticosteroids.

Question 9

Presentation of open angle glaucoma?

Answer 9

Peripheral visual field loss - nasal scotomas progressing to tunnel vision.
Decreased visual acuity.
Optic disc cupping

Question 10

Fundoscopy findings of open angle glaucoma?

Answer 10

1. Optic disc cupping - Cup to disc ration > 0.7.
2. Optic disc pallor.
3. Bayonetting of vessels (vessels break as they disappear into up and reappear at base).
4. Cup notching, disc haemorrhages.

Question 11

Normal cup to disc ratio?

Answer 11

0.4-0.7

Question 12

Investigations of open angle glaucoma?

Answer 12

Goldmann applanation tonometry - measure IOP.
Slit lamp examination.
Visual field examination.
Gonioscopy - angle between iris and cornea.
Central corneal thickness assment

Question 13

Management of open angle glaucoma?

Answer 13

Started when IOP > 24mmHg.
First line - 360 degree selective laser trabeculoplasty.
Second line - prostaglandin analogues
Third line - beta blocker eye drops, carbonic anhydrase eye drops, sympathomimetic eye drops.
If all above doesn’t work then may need trabeculectomy.

Question 14

Mechanism of action of following:
1. Prostaglandin analogues eye drops
2. Topical beta blockers
3. Sympathomimetic eye drops
4. Carbonic anhydrase eye drops

Answer 14

1. Prostaglandin analogues eye drops - increase uveoscleral outflow. May cause brown pigmentation of iris and increase eyelash length.
2. Topical beta blockers - reduces aqueous production but must avoid is asthmatics and patients with heart block
3. Sympathomimetic eye drops - reduces aqueous production and increases outflow
4. Carbonic anhydrase eye drops - reduces aqueous production

Question 15

Risk factors for acute angle closure glaucoma?

Answer 15

Increasing age,
Family history,
Female (4x more likely)
Chinese and east asian ethnicity,
Shallow anterior chamber
Meds - adrenergic meds (noradrenaline), anticholinergics, tricyclic antidepressants.

Question 16

Presentation of acute angle closure glaucoma?

Answer 16

Severely painful red eye, blurred vision, halos around lights and headache, N+V.
Signs - red eye, hazy cornea, decrease visual acuity, mid dilated, fixed pupil size, hard eyeball on gentle palpation

Question 17

Initial management of acute angle closure glaucoma?

Answer 17

Lie patient on back without pillow,
Pilocarpine eyedrops (2% for blue eyes, 4% for brown eyes) - pupil constriction and ciliary muscle contraction with increases drainage of aqueous fluid.
Acetazolomide 500mg orally.
Analgesia and antiemetic if required.

Question 18

Secondary management of acute angle closure glacuoma?

Answer 18

Definitive - Laser peripheral iridotomy - tiny hole in peripheral iris allowing aqueous humour to drain.
Others - pilocarpine eye drops, acetazolomide, hyperosmotic agents like manitol to increase osmotic gradient.