The European Society of Cataract and Refractive Surgeons (ESCRS, sister organisation of ASCRS in the US) held its twenty-second congress in Paris on September 18-22. Alas, other obligations meant that I only attended a fraction of the sessions and courses I had wanted to, but somehow I still managed to amass 25 pages of cryptic notes, from which, for the sake of finally putting out a long overdue KeratoScoop update, I will share some random anecdotes. (This will be mostly of interest to complications patients rather than candidates.)
 

Vision testing techniques and tools

Dr Jacques Charlier discussed contrast sensitivity and glare testing and presented on a motion perimetry test which uses bars of light, rather than the traditional dots, moved out of alignment. He argued that dot alignment can be perceived even through a dense cataract and therefore that a better technology was needed.

Dr William Jory argued for the importance of contrast sensitivity testing for all refractive patients pre-operatively and post-operatively and noted that for the most standardised test (Pelli Robson) there are no cost barriers to which to attribute the failure to test.
 

Vision quality, night vision disturbance, et cetera

The Saturday session on night vision was somewhat disappointing as a night vision session per se but it did yield some interesting talks.

Dr William Jory chastised doctors for frequently dumping contrast sensitivity in the night vision disturbance bucket, since starbursts, haloes et cetera (classic NVD) are distinct phenomena with distinct causation. He presented a list of unpublished studies (including one done at Moorfields Eye Hospital) showing anything from 18.5% to 75% of patients with reduction of contrast sensitivity following laser refractive surgery. He discussed his concerns about the implications of acoustic energy penetrating the stroma. He challenges the industry, and ESCRS, to advocate CS pre-operative measurements, CS testing as part of driving testing for refractive patients, and requirements for NVD warnings in laser surgery ads (stating that laser manufacturers' ads include such warnings).

Cynthia Roberts gave a presentation focusing on the shortcomings of current technology in creating the best eye shape for good vision quality and in particular on the need for optimising laser surgery with biomechanics, on the grounds that predicting individual responses (rather than a population average), i.e. developing individualised nomograms, is key to progress. [Hear, hear!] She noted that the Wavelight's standard profile has a more biomechanically friendly profile than any other laser. She focused on the peripheral steepening effect and gave an example of a patient treated only peripherally who still had induced flattening in the centre. If I understood correctly she indicated that the increased problems from a wider zone treatment could basically cancel out, because of the unpredictable biomechanical response centrally, any perceived advantage of using a wider zone.

Dr Do H Lee stated that vision quality is the most important factor in measuring success in refractive surgery. He addressed the question of whether the traditional approaches to vision quality optimisation – larger optical zone, blend zone, smoothing – were really succeeding in inducing fewer higher order aberrations and therefore whether they were worth the tradeoffs of deeper tissue removal and higher ectasia risks. He presented data from a study of 40 eyes where one eye was given a 6.0 zone and the other a 6.25 zone and found that they had approximately the same amount of HOA; and another study of 30 eyes where 1 eye was given a wavefront-guided 6.0 zone and the other a conventional 6.25 ablation. >50 of patients preferred the wavefront eye.

Dr Lohmann presented on wavefront guided secondary LASEK on a Wavelight Allegretto to treat night vision disturbance induced by LASEK. (In these patients NVD was attributed to small optical zone vs the pupil size, and high order aberrations.)   Of 21 eyes re-laseked in this way 18 had “no night vision problems” post-operatively while 3 were “improved but not perfect”. Interestingly, he commented that for a primary treatment he saw no difference on the Wavelight Allegretto between the standard nomogram and the wavefront-guided treatment. He also staed that for correction of previous surgeries he prefers topography-guided treatments as they are “more reliable” than wavefront.

Dr Ioannis Pallikaris gave an interesting and very technical tock on light scattering versus the healing response in night vision disturbance. He made the distinction between small and wide angle scattering and their contribution to visual phenomena, with the former affecting visual acuity and the latter affecting contrast sensitivity. He showed an example where small angle scattering had a far worse visual result in terms of what the patient saw but was not visible on the slit lamp. He indicated that the solution they need to find is a way to “induce less keratocyte activation”.
 

Instructional course on complications prevent and management

This was course run by a panel of Dr Michael Assouline, Dr Nico Trap, Dr Jerry Tan, Dr John Kanellopoulos, and Dr Sheraz Daya. It was content-intensive and I will only share a few interesting bits.

There was a general comment that complications had reduced over the years. (Anecdote: “I had a non paying patient recently. Is that a complication?”)

Screening for ectasia was discussed at great length, and comments about or examples of ectasia came up repeatedly throughout the session. During the pre-operative screening part, many opinions were shared about how to identify the borderline cases. Considerable emphasis was placed on Orbscan and attendees were encouraged to buy one if they didn't already have one. There was an interesting discussion about “whether we are creating an ectasia time bomb with the forme fruste keratoconus patients” and an acknowledgement that this might be the case. There was considerable discussion about how much stroma to leave. Dr Kanellopoulos stated that he always leaves 280um under the flap. Another doctor commented that if he does that he “must turn away an awful lot of patients”. He said no, he simply does a smaller zone on the basis that he'd rather his patient have NVD than ectasia – but he discusses it all up front with the patient and leaves it up to the patient to decide whether to proceed with surgery.

Dr Tan discussed an unconventional wavefront-guided retreatment where he treats the back of a flap (if the stroma is too thin).
 

Instructional course on LASIK, LASEK and PRK nightmares

Dr Marguerite McDonald gave a presentation building the case for a return to advanced surface ablation. Her basis premise was that ASA gives superior outcomes in terms of inducing fewer higher order aberrations than LASIK and therefore that it is better for patients, but that the questions ASA raises are whether we can speed visual recovery and control pain. Her presentation addressed ways of doing both.

During some general discussion there was a case mentioned of an old RK patient who had progressive hyperopia. When he reached +5.0, the surgeon (panel member) did LASIK, preferring that over surface ablation because of the haze risk. Dr Lindstrom countered that the problem with LASIK over RK is that the progressive hyperopia just keeps on going. He also mentioned the heightened risk of epithelial ingrowth and said he is investigating suface ablation for RK patients. (At another point in the discussion Dr Lindstrom emphasized that enhancement should not be done on LASIK patients if the aberrations are mild; he wants to be convinced it's clinically significant because “Flap lift enhancements have three times the complications rate of primary treatments, if we're honest about it.”)

Dr Dan Durrie presented on Ladarwave retreatments (he calls them “upgrades”) for patients with poor optics. He discussed the fact that patients with small optical zones present real problems because the wavefront data capture in the periphery is poor. He also discussed issues of pupil centration and registration when doing wavefront retreatments and the need to get the word out to the manufacturers about the problem of the dilated pupil centre being significantly different than when constricted.

Dr Lindstrom commented that when you measure a large pupil but treat a small pupil that's when the problems occur. He says the way they do it is to turn the light down (to prevent constriction) until the lasers incorporate limbus measurement or iris recognition.

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Well, there's far more than that, but this will at least give a little flavour.