It may be preferable to use 10% phenylephrine as this ensures greater dilution of other agents contained in the drops. Adequate mixing of agents must be ensured by using 2.5 ml or 5 ml syringes only (avoid 1 ml syringes). Phenylephrine (prepared from 2.5% or 10% preservative-free drops) can be prepared with concentrations ranging from 0.5% to 1.5%. Many eye units routinely add 0.5 ml of preservative-free adrenaline (1 mg/ml) to 500 ml of balanced salt solution or Ringer’s lactate to help maintain dilation during cataract surgery for patients who have a small pupil or a floppy iris, stronger intracameral agents can be used. Be sure to remove them before the procedure. Optimal dilation can be promoted by putting little pieces of surgical sponge or cotton wool soaked in 10% phenylephrine, or a mixture of phenylephrine and cycloplegic eyedrops, into the inferior fornix 30 minutes before surgery. Pharmacological dilationĪvoid dilating more than 1–2 hours before surgery as the dilation effect wears off and subsequent drops work less well. Careful consideration should be given to IOL choice or even aphakia, especially in younger patients with uveitis (pp. If they were caused by uveitis, aggressive management of peri-operative and postoperative inflammation will be essential for obtaining a good outcome. Where posterior synechiae are present, consider whether these were caused by uveitis, rather than by previous infection, surgery or trauma. Pre-operative NSAID drops, such as ketorolac, nepafenac or diclofenac, instilled 30–90 minutes before surgery, have been shown to maintain pupil dilation during surgery. Patients using topical pilocarpine should be asked to stop at least three weeks before surgery.The amount of IFIS does not seem to be related to the dose or the duration of the therapy, 2 so stopping these medications, even several months before surgery, often does not reverse this effect. They also affect the iris, causing poor dilation and intraoperative floppy iris syndrome (IFIS). Oral alpha blocker medication, such as tamsulosin or doxazosin, help urinary symptoms by relaxing the smooth muscles of the bladder neck.Take a careful history and ask patients about the medication they are currently using. 1 Pre-operative action can sometimes improve this situation, but the solution frequently involves changes in surgical technique. Removing a cataract, typically around 10 mm in diameter, is made much more difficult when a patient has a small pupil the risk of rupture of the posterior capsule during surgery is also 50% higher. Related content Cataract surgery is more difficult when a patient has a small pupil, but optimising pharmacological dilation and adapting surgical technique can ensure good outcomes. John Buchan Ophthalmologist: International Centre for Eye Health, London School of Hygiene and Tropical Mariano Yee Melgar Ophthalmologist: Visualiza, Guatemala, Central America.
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