Sourdille calls for LASIK standardisation

By Roibeard O’hEineachain

Nantes — The current lack of standard preoperative and postoperative assessment protocols limits both the present and the future of refractive surgery, according to French ophthalmologist Philippe Sourdille MD.

“At present we have differences in evaluation instruments and protocols that can make results from different study centres difficult to compare. We also have non-optical disorders that we need to include in our evaluation if we are to test the eye comprehensively.

“If we are doing three million new refractive procedures every year and we have a 1% complication rate, that is still 30,000 eyes that will need to regain some vision,” he notes.

The main non-optical problems associated with refractive surgery are ocular surface disorders, which can influence wound healing and ocular comfort. Ocular surface disorders can be pre-existing or can be induced by the preservatives in topical antibiotics.

Dr Sourdille noted that patients particularly at risk from preservatives are those with inadequate tear secretion in whom the preservative benzalconium chloride can have deleterious effects on the conjunctiva.

“We should remind ourselves that preservative-free antibiotics should be used especially if there is a risk from associated pathologies in the future, such as glaucoma in highly myopic eyes.

“There is also a need to include in our protocol preoperative and postoperative assessment with factors like the lissamine green lachrymal film break-up time and, if necessary, conjunctival impression cytology,” he advised.

Don't forget retina and vitreous
The potential iatrogenic effects of refractive surgery on the retina are another cause for concern. Highly myopic patients make up a high proportion of those undergoing such procedures. Under normal circumstances their retinal detachment rate is seven times that of non-myopic patients but their risk may be increased by the mechanical stresses induced by the suction on the eye used in LASIK.

Dr Sourdille cited an Argentinean study in which the positive perception of floaters increased from 8% in high myopes to 32% after LASIK. In addition, postoperative light flashes and partial and total posterior vitreous cortex detachment can increase from 2% in low myopes to 24%.

“So apart from all the usual optical factors and clinical assessment, I think that ocular surface examination and detailed retinal and vitreal status should attract our interest, as it will most likely attract the attention of lawyers.

“The difficulty is that with so many different measurement systems available, we need to arrive at a consensus on how to assess our patients before and after surgery. Nonetheless, we need to establish accepted official norms when we present our results,” he said

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