FRCA Notes

Cataract Surgery

It would be remiss to not have a (brief) entry dedicated to the most common operation performed worldwide.

The curriculum calls for us to 'discusses the choice of... anaesthetic technique... with particular reference to... cataract surgery'.

Resources

The goal is to provide pain-free (albeit not discomfort-free) surgery with minimal systemic and surgical complications
To that end, local anaesthesia is the preferred method, unless contraindicated

Reduced morbidity vs. other techniques
Disrupts daily routine less
Facilitates high turnover, with consequent patient, health-economic and private-surgeon-economic benefits

Indeed 96% of case are performed under LA, of whom ~1.5% require sedation
A previous Cochrane review favours sub-Tenon's over topical anaesthesia
However the majority (>90%) are done under a combination of topical drops + intracameral injection, which is superior to topical anaesthetic alone (Cochrane, 2020)

Of those requiring regional techniques, sub-Tenon's block is most common

There is a 2.5x decrease in complications with sub-Tenon's vs. sharp needle techniques
Sharp needle techniques should only be performed when absolutely necessary

The remainder are performed under either peribulbar or retrobulbar block

Phenylephrine 2.5% - 10%

This familiar, albeit more concentrated, ɑ₁ agonist causes pupillary dilation
May cause HTN, arrhythmia or coronary vasospasm

Cyclopentolate 0.5% - 1%

This much less familiary parasympatholytic also causes pupillary dilation
May cause confusion or psychosis

Often a combination of tropicamide 1% + phenylephrine 2.5% + cyclopentolate 1% is used
Many centres use mydriasert (tropicamide + phenylephrine), a pellet inserted into the inferior fornix and removed immediately pre-operatively

Wrong eye LA administration
Wrong eye surgery
Wrong lens insertion