Lecture 6 - Ocular procedures and related formulations

Question 1

What is the purpose of cataract surgery?

Answer 1

It is the procedure of removing the lens of a patient and replace it with an artificial intraocular lens. Modern IOLs use silicon or acrylic polymers which can be inserted through 3mm incision compared to older PMMA lens which used a 7mm incision.

Question 2

What are the potential risks of cataract surgery?

Answer 2

Infection
Post operative inflammation
Posterior capsule opacification
Secondary cataracts

Question 3

What is the use of drug-elutive intraocular lens?

Answer 3

potential for postoperative delivery of antibiotics and anti-inflammatory medication.

Question 4

What is the purpose of ocular bandages?

Answer 4

They provide a protective hydrogel film barrier while stabilising ocular wounds. It is designed to promote healing by protecting the corneal incision from eyelid trauma.

Question 5

What is Keratoconus?

Answer 5

It is an ocular degenerative disease that affects the cornea, which gradually weakens, progressively thins and becomes irregularly shaped which results in astigmatism and blurred vision.

Question 6

Describe the process of cross linking.

Answer 6

This procedure requires the removal of the corneal epithelium in a 6-7mm diameter central zone. Then 0.1% riboflavin solution is applied. It is irradiated with UVA at 370nm. The UVA light activate the ribloflavin which produces reactive oxygen species which induces covalent bond between collagen fibrils in the corneal stroma.

Question 7

What is the purpose of LASIK.

Answer 7

It is a surgery performed by ophthamologist who uses a laser to reshape the cornea in order to improve visual acuity.

Question 8

List the LASIK risks and side effects.

Answer 8

Infection and inflammation
There is a small chance, vision might still not be perfect.
Side effects are:
blurred vision
difficulty with night vision
glare
light sensitivity
halos around light
discomfort/pain

Question 9

List a few examples of drugs used for ocular.

Answer 9

Povidone-iodine 5% eye drops (before surgery antiseptic)
Ketorolac trometamol 5mg/ml (post operation NSAIDs)
Azithromycin ophthalmic solution 1% (post operation antibiotic)

Edetate disodium (chelating agent to improve permeability)
Polycarbophil (in situ gelling agent to improve residence time)