ROBOTIC SURGERY

Femtosecond laser-assisted cataract surgery (FLACS) may have the potential to mature into a procedure that can provide a safety advantage over ultrasound phacoemulsification and it has a prospect of evolving into surgeon-directed robotic surgery in the future, said Paul Rosen FRCS, FRCOphth, Oxford University Hospital, Oxford, UK.

“FLACS increases the automation of cataract surgery procedures, and therefore offers a reduction in the variability and potentially improved safety of the procedures. An achievable benefit lies in its ability to reduce the ultrasound energy input required for phacofragmentation, which will in theory reduce endothelial cell loss, reduce inflammation and reduce complications,” Dr Rosen told the XXXII Congress of the ESCRS in London.

He noted that in the types of cataracts surgeons most commonly encounter, phacofragmentation FLACS can reduce effective phaco time to a minimum, sometimes to zero. In fact, Bausch & Lomb have already designed a 20-gauge aspiration handpiece for removal of laser-fragmented lenses.

However, the reduction in ultrasound input has to be weighed against the input of laser energy, which carries its own risks. With the simpler fragmentation patterns there is little risk, but also little benefit in terms of reduced ultrasound usage. With the more complex fragmentation patterns there is a greater reduction in ultrasound usage but also higher risk of gas bubble formation within the capsular bag, with the potential to cause posterior capsule rupture.

FLACS may also lead to an increased inflammatory response, as demonstrated in a study conducted by Burkhard Dick MD, which showed an increased level of prostaglandins in ocular fluid following FLACS. “Many people perceived that the FLACS device is here now, in its developed form, but we are very much at the beginning of this exciting journey,” Dr Rosen said.

Refining the technology

A reduction in the hazards associated with phacofragmentation may be achieved through a refinement of the laser’s pulse frequency, beam structure, spot size and grid size, and the imaging systems used to guide the procedures, Dr Rosen said.

He noted that a study conducted in Bochum, Germany comparing phacofragmentation patterns with different grid sizes showed that effective phaco time was only 0.03 seconds with a 350-micron grid, compared to 21 seconds with a 500-micron grid. The mean absolute phaco times were 2.05 seconds and 5.85 seconds respectively (Conrad-Hengerer et al, J Cataract Refract Surg. 2012 Nov;38(11):1888-94).

Dr Rosen noted that robotic technology is already making inroads into other surgical disciplines. Such developments will come to ophthalmology, but they will be driven by surgeons as additions to the surgical toolkit like any other instrument. Surgeons will remain as the clinical decision makers, and such advanced technologies will be used to enhance our surgical skills.

Paul Rosen: paul.rosen@orh.nhs.uk