Getting and maintaining a large pupil
Intracameral mydriasis (ICM) provides very rapid mydriasis and can also help stop iris haemorrhage
“Changing Pharmaceutical Treatment Patterns in Cataract Surgery” was the topic of the Main Symposium at the 2017 annual meeting of ESCRS in Lisbon on Sunday. Conceição Lobo, Coimbra University Hospital, Portugal, updated delegates regarding the best ways to achieve and maintain a large pupil during cataract surgery.
“Intracameral mydriasis (ICM) provides very rapid mydriasis and can also help stop iris haemorrhage, due to the vasoconstrictive effects,” said Dr Lobo.
Dr Lobo reported that randomised clinical trials have shown that the intracameral combination of phenylephrine 2.5% + tropicamide 1% is equally safe and more effective than lower concentrations. The recommended concentration for adrenaline is 1:1,000,000, due to its potential for endothelial toxicity.
Other possibilities are Mydriasert inserts (phenylephrine 5.4mg + tropicamide 0.26mg) for the inferior fornix and Mydrane (phenylephrine + tropicamide + lidocaine), both from Théa Laboratoires.
Dr Lobo also offered some tips for the preoperative evaluation. “Eyes with a pre-op dilated pupil diameter of 7.0mm or smaller are at risk for IFIS, regardless of alpha-1 antagonist treatment history,” she said. In these patients, more extensive precautions, either preoperatively or during surgery, might help avoid pupillary problems that could lead to complications.
If pharmacologic means are insufficient to achieve or maintain adequate mydriasis, mechanical means such as pupillary expanders or viscoelastic devices (OVD) must be used.
“A combination of a viscoadaptive OCD, which mechanically stretches the pupil, and a dispersive OVD, which resists aspiration, can maintain mydriasis for the duration of surgery.”