CLM - Non-Surgical Management of Myopia III - Week 9 Flashcards
List two topical, muscarinic (M) receptor antagonists and their selectivity.
Atropine (non-selective)
Pirenzepine (more selective for M1 receptors)
Briefly describe a possible direct effect and three indirect effects of muscarinic receptor antagonism for their mechanism of action. Is it well understood?
Direct effect
-muscarinic receptors in the posterior eye
Indirect effect
-reduced accommodation (unlikely)
-alternations in neurotransmitter release
-changes to patterns of -systemic growth hormone release
Mechanisms are not well understood
Describe the direct effect of atropine on muscarinic receptors (and the consequences of this) and on the sclera.
Atropine boosts the release of dopamine by amacrine cells
Also acts on scleral fibroblasts, possibly interfering with scleral remodelling
What are two major findings of the ATOM study on the use of atropine for myopia progression?
1% topical atropine reduced myopia progression by 77% over two years compared to controls and untreated eyes
No serious adverse events reported from using atropine
Consider atropine treatment for myopia control. What do studies suggest if the use of atropine is stopped?
Post-treatment, atropine treated eyes showed more rapid myopia progression
List short-term ocular side effects of 1% atropine for myopia progression and its implication if applicable.
Photophobia (mydriasis)
Blurred vision (cycloplegia)
-potential effects on learning ability and sporting activities
Headaches/brow aches
List two possible long term ocular side effects of atropine for myopia progression.
Not fully known
Increased risk of UV related retinal damage
Cataracts (UV related)
What is atropine for myopia progression typically prescribed with and why?
Photochromatic PALs due to its mydriatic and cycloplegic effects
Describe the ATOM2 study and its two major findings and a flaw.
Investigated the use of 0.01% atropine for myopia progression in place of 1%
Found negligible effects on pupil size and accommodation
It is limited by a lack of a true placebo/control group
What was the major finding in comparing lower doses of atropine with higher doses for myopia control?
0.01% eyedrops were more effective in slowing myopia progression with less visual side effects compared to higher doses
Compare the rebound of myopia progression when treated with high or low doses of atropine.
Greater rebound with higher doses of atropine
Is the effect of atropine on myopia progression dose-dependent?
Yes, the lower the dose, the less effect it has
What is the maximum dose of atropine without clinical signs or symptoms?
0.02%
Does 0.01% atropine significantly attenuate axial length change?
No
What has been proposed as the optimal dose of atropine for myopia progression control? (LAMP study)
0.05%