Ocular Procedures and other related formulations

Question 1

Describe how cataract surgery works

Answer 1

Procedure removes the original lens of patient to replace with artificial intraocular lenses (IOL)

Requires use of tetracaine hydrochloride 0.5% w/v eye drops

Question 2

What are intraocular lenses made of

Answer 2

Poly (methyl methacrylate): needed a 7mm insertion to be made

Modern: soft polymers based on silicone or acrylic: needs a 3mm insertion to be made

Question 3

What are the risks of cataract surgery and possible solutions

Answer 3

1. Infection
2. Postoperative inflammation
3. Posterior capsule opacification
4. Secondary cataracts: epithelial cell adhesion and proliferation of posterior lens capsule

Question 4

How do you avoid the risks in cataract surgery

Answer 4

Drug eluting intraocular lenses have potential for delivering antibiotics and anti-inflammatory medication

Question 5

Give an example of an ocular bandage and the role of it

Answer 5

1. OcuSeal Liquid Ocular Bandage
   Applied topically to the eye to prevent any trauma occurring to incision made in the cornea after operation (promotes healing)
2. Provides a protective hydrogel film barrier whilst stabilising ocular wounds

Question 6

What is Keratoconus

Answer 6

Cornea weakens and becomes abnormal in shape

Results in blurred vision and astigmatism (light scattering across retina)

Question 7

How do you treat keratoconus and describe the method used

Answer 7

Corneal cross linking method:
Brushing off cornea clear layer: 6-7mm

Ribovarin 0.1% drops applied

Ultraviolet A 370 nm switched on, two react to create cross linking effect to stiffen them (prevents vision loss in future)

Mechanism: generates reactive oxygen, induces covalent bonds between collagen fibrils in corneal stroma

Question 8

What is a penetration enhancer and give an example of one

Answer 8

Used to increase concentration of drug

Example: Cyclodextrins

Ricrolin: drug that contains riboflavin and cyclodextrin to increase concentration of it

Question 9

What is laser eye surgery used for and what does it mainly o

Answer 9

1. LASIK surgery: performed by ophthalmologist using a laser or microkeratome: reshapes cornea to improve visual acuity
2. Provides alternative to glasses or contact lenses
3. Near sighted patients: can flatten cornea that is too steep
4. Far sighted: allows steeper cornea achieved
5. Moves cornea back into natural shape

Question 10

What are the risks of laser eye surgery

Answer 10

Infection and inflammation risk

Vision will not be as good after surgery even with glasses or contact lenses

Question 11

What are the complications of laser eye surgery and the side effects

Answer 11

1. Inflammation and infection risk
   Chance vision will not be as good after surgery even with glasses or contact lenses on

2. Side effects:
Blurry vision
Night vision difficult
Glare
Halo lights
Light sensitivity
Discomfort or pain
Small or pink patches on sclera

Question 12

What are the anaesthetic drops used before laser eye surgery

Answer 12

Povidone Iodine 5% w/v eye drops

Chemical complex: poly-N-vinylpyrrolidone (PVP) and elemental iodine

Question 13

What is an iodophors

Answer 13

Broad spectrum antiseptic properties for topical application

Question 14

What do you use post operative treatment for laser eye surgery

Answer 14

Ketorolac trometamol 5mg/mL

API: NSAIDS

Question 15

What other post operative antibiotics are available

Answer 15

Azyter eye drops (azithromycin): Made up of medium chain triglycerides

AzaSite (azithromycin 1%):
polycarbophil: polyacrylic acid: in situ gelling agent
Edentate sodium: chelating agent to increase permeability
Sodium Chloride: tonicity