SCREENING LASER VISION CORRECTION PATIENTS

Surgeons should carefully document the screening results of all their laser vision correction patients prior to surgery to avoid any medico-legal issues down the line, advised Saj Khan FRCSEd(Ophth), Corneoplastic Unit and Eye Bank, East Grinstead, UK. He told the XXXV UKISCRS Congress that he takes the basic premise when approaching the screening of laser vision correction patients that none are suitable for treatment unless proven otherwise. “In an ideal world we would be able to offer everybody perfect unaided visual acuity post treatment and we would perform treatments that have no complications,†he commented. Since that is not possible, ensuring accuracy of the necessary measurements to achieve the optimum desired outcome, with the bottom line of safety for the patient is the way to go, Dr Khan advised. For surgeons themselves this approach is also in their best interests, in terms of reputation and for medico-legal reasons. Discussing the diagnostic modalities he most commonly uses on his laser vision correction patients, Dr Khan listed topography, tomography, wavefront analysis, specular microscopy, anterior segment optical coherence tomography and retinal OCT of the disc/macula. The key issues Dr Khan screens for through tomography/topography include irregular astigmatism, asymmetric bow tie, inferior steepening, I-S pachymetry difference, displaced apex, thinning, steep Ks (keratometry) and posterior elevation. He said that while much equipment nowadays can do more than one screening task, he prefers having more than one machine that can do the same thing. For example, Dr Khan stated the slit scanning system is not as good a tomographic data generator as the Scheimpflug imaging system of the Pentacam. “So having another form of tomography device is essential for confirming the data that you have. Generally there are a lot of people who say that once you have moved on to the newer generation of technology you shouldn’t bother with the older one but it is always reassuring to know you have consistency,†he told the meeting. Surgeons’ biggest fear when doing refractive surgery is the risk of ectasia and that is difficult to screen for even with the latest improved technologies, he noted. “There are many things we look for that we believe are indications for patient’s risk of ectasia but we’re still looking for that Holy Grail that will eliminate the risk completely,†Dr Khan commented. He said the Visante OCT system is a good modality for providing detailed images of the anterior segment and the cornea in particular, which has changed the surgeon's ability to assess volume within the cornea and also utilise that information to help plan how to overcome any issues. He said he doesn’t typically use the imagery from the OCT unless he has concerns about discrepancies between the Pentacam and the Orbscan. However, while it is a bit slower to use, the OCT gives a different detail and added security when extra reassurance is needed. Furthermore, Dr Khan said he probably uses the fundal examination more than some of his colleagues as he finds it very reassuring. While screening modalities continue to improve and some claim to give a complete picture of what needs to be considered, none of these things can be taken in isolation, Dr Khan maintained.

Litigation protection

Dr Khan also strongly advised surgeons to take pictures/ copies of the screening findings of all potential patients. “As our world becomes more litigious and we worry about medicolegal ramifications later on in life, having a documented diagnostic examination that you can keep long term is likely to save a lot of people who would otherwise rely on people to trust their integrity, which is unfortunately happening less and less. “You’ll always find somebody who is prepared to challenge you if you can’t give them objective evidence that what you did at the time was entirely consistent with accepted practice and believed to be safe for the patient,†he contended. Overall for his practice, Dr Khan said the key benefits of the diversity and accuracy of modern diagnostic imaging devices is that they maximise the potential for getting the desired outcome from both the patient’s and surgeon’s perspective.