Suction loss during SMILE

Cheryl Guttman Krader

Posted: Wednesday, November 1, 2017

Dan Z Reinstein MD

The incidence of suction loss during SMILE is low, and as further good news, its occurrence does not prevent patients from undergoing refractive surgery or adversely affect the outcome, according to a study presented by Dan Z Reinstein MD at the XXXV Congress of the ESCRS in Lisbon, Portugal.

Professor Reinstein, Medical Director, London Vision Clinic, London, UK, analysed experience with suction loss in a series of 4,000 consecutive eyes treated by SMILE at his centre. Consistent with incidence data from previously published studies of patients undergoing SMILE post-learning curve, Dr Reinstein found that suction loss occurred in 20 eyes (0.5%).

Among the 20 eyes, suction loss occurred most often during cutting of the lenticule interface (45%), followed by during creation of the cap interface (20%). Suction loss was most often patient-generated (75%) rather than surgeon-initiated or device-related, and due to involuntary movement associated with Bell’s reflex (50%) or because the patient was inappropriately tracking the green light (30%). SMILE was completed in 60% of the eyes with suction loss, and all of the remaining cases were successfully converted to LASIK.

Nineteen of the 20 patients underwent SMILE in the fellow eye and served as a control group for an analysis of the results of SMILE in eyes with suction loss. Compared to the fellow eyes, the eyes with suction loss had similar efficacy, safety, accuracy, stability and refractive cylinder outcomes.

Preventing and addressing suction loss
Dr Reinstein emphasised that the surgeon has the major role in preventing suction loss.

“Surgeons should be constantly talking to the patient, giving clear instructions about the fixation light in a calm, reassuring voice, while intensely monitoring for eye movement and having a high sensitivity for aborting the cut,” he said.

The laser software contains a “restart treatment wizard” that provides guidance on whether to continue SMILE or convert to LASIK, but the program only takes into account timing of the suction loss. By applying his own clinical knowledge and experience, Dr Reinstein said he has created a decision pathway that factors in understanding of the bubble pattern and potential strategies for continuing with SMILE rather than converting to LASIK, which will be published in his textbook in 2018: The Surgeon’s Guide to SMILE (Slack Inc).

He illustrated the algorithm by describing a case where there was patient-generated suction loss during cutting of the lenticule interface. Rather than converting to LASIK, which would be the wizard’s recommendation, Dr Reinstein reprogrammed the SMILE cap thickness from 135 to 110 microns. He completed the procedure successfully without complications and with an excellent outcome.

Dan Z Reinstein: