6.1.11 - Treatment of a range of ocular conditions

Question 1

What are the first line therapies for glaucoma?

Answer 1

Prostaglandin Analogues or Beta-blockers

Question 2

What is the function of prostaglandin analogues & name 3 examples ?

Answer 2

-increases outflow of aq humour via uveoscleral pathway (10% of drainage)
-Latanaprost (Xalatan)
-Bimatoprost (Lumigan)
-Travoprost (Travatan ) * trade name

Question 3

What is the dose of P. analogues and cautions?

Answer 3

-taken 1 * daily (preferably in the evening)
-More expensive
Cautions:
-Take 2-3 weeks to achieve max therapeutic effect
-conjunctival irritation + vasodilation
-iris gets darker
-eyelashes darken/thicken/lengthen
-skin around eyes darkens

Question 4

What is the function/indications of Beta-blockers & name 3 examples?

Answer 4

-It reduces the production of aq humour by blocking ciliary body / reduces IOP by about 25%
-Indicated for IOP >30mmHg
Examples:
-Betaxolol (Betoptic)
-Carteolol
-Timolol
Levobunolol

Question 5

Beta-blockers:
name the dosage, benefits & cautions?

Answer 5

taken 2* daily
-reduces IOP by about 25%
-No change to pupil diameter + doesn’t change iris colour
Cautions: (systemic absorption)
-Bradychardia , heart failure, heart block
-Asthma, obstructive airways disease interactions with other drugs?
-patients already on beta-blockers?

Bradycardia= slower heart rate than normal

Question 6

What is the 2nd line of glaucoma treatment + indications? Give an example!

Answer 6

a combination of Prostaglandin analogues and Beta-blockers, e.g.,
Xalacom.
-This is given if IOPs do not reduce with first line of treatment.

Question 7

What is the 3rd line of therapy?

Answer 7

Alpha-2-agonists or Carbonic Anhydrase Inhibitors (CAI).

Question 8

How do alpha-2-agonists work & dosage?

Answer 8

-Reduce aq humour production + increase drainage (via uveo scleral pathway)
Taken 2* daily

Question 9

Name examples of alpha agonists and cautions?

Answer 9

Cautions:
-ocular allergy
-dry mouth
-fatigue and drowsiness

Examples:
-Brimonidine
-Aprachlonidine

Question 10

What is the function of CA inhibitors & examples?

Answer 10

-Reduce aq humour production by:
reduces carbonic anhydrase (enzyme) activity in the ciliary processes (site of aq humour production)–> so bicarbonate production is reduced (from enzyme)–>leads to aq humour reduction.
Examples:
-Brinzolamide
-Dorzolamide
-Acetazolomide

Question 11

How is CA administered , dosage & indication?

Answer 11

-Administered topically & systemically (i.e eyedrops and pills)
-taken 2- * daily
-IOP <30mmHg

Question 12

What is CA specifically licenced for, Cautions ?

Answer 12

-licenced ONLY as an alternative / combination with beta- blockers
-Not as effective as beta-blockers
Cautions:
-Topical use-> well tolerated but unpleasant taste (effects taste receptors)
-Systemic use-> not recommended for long-term use

Question 13

What can be used in IOPs over 30mmhg + how does it work?

Answer 13

Pilocarpine–> to increase outflow of aqueous humour by ciliary
contraction

Question 14

What are the 3 types of glaucoma treatment?

Answer 14

Laser treatment:
-Selective laser trabeculoplasty (SLT)
-YAG laser iridotomy
Surgical treatment:
-Trabeculectomy

Question 15

What is Selective laser trabeculoplasty (SLT) + its effect?

Answer 15

• increasingly used as a first line treatment to lower IOP.
  -Laser is applied directly to the trabecular meshwork to help open the drainage.
• This method lowers IOP by 20-30% and has a duration of actions of 1-5years.

Question 16

When is YAG laser iridotomy used? & what happens?

Answer 16

• Mainly used in treatment of ACG and pigment dispersion
  syndrome due to inadequate aqueous drainage.
  -Focused laser beam is used to create a small opening through the
  iris. This allows trapped fluid behind the iris to flow into the front
  of the eye, thus reducing IOP

Question 17

How does Trabeculectomy work?

Answer 17

*Filtration surgery that reduces IOP by creating a fistula.
-small incision made in the conjunctiva under the upper eyelid
-> scleral flap is created under the incision / small piece of tissue is removed
under the flap –>to make opening into the eye.
*sometimes small piece of iris removed aswell= IRIDECTOMY
->flap sown back into place to control the
flow of the fluid
->fluid draining out is collected into a filtering
‘bleb’ and this looks like a bubble; however, this
is hidden under the upper eyelid.
->The fluid in the bleb does not leave the eye and
is reabsorbed back into the blood stream.

Question 18

What are the ways of treating cataract?

Answer 18

-Phacoemulsification
-Extracapsular cataract extraction (ECCE)

Question 19

Explain the phacoemulsification process?
Hint- emulsify

Answer 19

-Cataract extraction method
1.Topical local anaesthetic instilled into the conjunctival sac.
2.Two small corneal incisions are made, approximately 180 degrees apart.
3.Fluid is inserted through the incision to support surrounding structures.
4. Top of the lens capsule is removed to gain access to the cataract.
5.Ultrasonic waves used to fragment and emulsify the clouded portions of the lens.
6These portions are then removed with a vacuum.
- An IOL is then inserted.
- The incisions may be sealed with corneal stromal saline injection

Question 20

Explain the ECCE process during and after?

Answer 20

Extracapsular cataract expulsion
** Used when there is an extremely dense nuclear opacity. compared to phacoemulsification–>
1. large limbalincision of approx 8-10mm is created. Big enough to remove the
cataract in one piece. IOL is placed in lens capsule
Post-removal?
- Requires stitches.
- Slower to recover compared to phacoemulsification.
- patch is placed to cover the eye post-surgery.
-Outpatient procedures (same day discharge).
*Bright light may be uncomfortable + No driving.

Question 21

What is the most common complication of cataract surgery + explain?

Answer 21

PCO (posterior capsular opacification)
-occurs bc cells remaining after cataract surgery grow over the back (posterior) of capsule –> cause to thicken + become slightly opaque (cloudy). This means that light is less able to travel clearly through to the retina at the back of your eye.

Question 22

What is the fix for PCO?

Answer 22

• Commonly treated with YAG laser.
• Topical local anaesthetics and mydriatics instilled.
• Laser is used to create an opening in the back of the eye’s cloudy lens capsule. This allows
  the light to pass through the lens and focus properly on the retina, restoring clear vision.

Question 23

Diabetic retinopathy treatment- who is this for?

Answer 23

Treatment is only available for proliferative retinopathy (R3) and maculopathy (M1) .Anything before R3 – treated via screening, diet and medication

Question 24

what are the treatments for DR?

Answer 24

there’s 3 : ALL laser
-Scatter laser treatment
-Focal laser photocoagulation
-Grid laser photocoagulation

Question 25

Explain scatter laser treatment ?
AKA (PRP) - panretinal photocoagulation

Answer 25

*laser treatment for R3-proliferative retinopathy
1. Local topical treatment instilled in eye
2. laser applied to peripheral retina
–> blood vessels shrink + stopped from growing in future
–>reduces chance of vitreous haem and RD
3. Multiple treatments may be required
(FYI - VIT Haem- new BV grow forward into retina , entering vitreous or get PRE-retinal haem +
if fibrous tissue grow -assoc with new BV, and it contracts= RD)

Question 26

explain Focal laser photocoagulation?

Answer 26

• Laser treatment for diabetic maculopathy
• Laser burns are applied directly to leaking microaneurysms.

Question 27

Explain Grid laser photocoagulation?

Answer 27

-Laser treatment for* diabetic maculopathy. M1* (treat macula oedema)
- Laser burns are applied to leaking microaneurysms that are no closer than 500μm to the macula or optic disc,
- So, if leakage is more on macula or optic disc, grid laser is used and directly lasering these
structures would cause oedema/further damage