femtosecond laser cataract surgery- magic or myth? a balanced view
DESCRIPTION
Femtosecond lasers are being touted as the next great leap forward in cataract surgery but, as with any radical change to our practices, many questions remain: Does this technology truly improve cataract surgery? Is the refractive accuracy better? Is the safety profile significantly elevated compared to existing technologies? Are there additional complications or issues with using this laser?TRANSCRIPT
EastwoodEye Surgery
Dr Gagan KhannahOphthalmic Surgeon
Eastwood Eye SurgeryMacquarie University Hospital
Sydney Eye Hospital
PresMed Annual Optometrist Conference10th March 2013
Femtosecond Laser Cataract Surgery – Magic or Myth?
A Balanced View!
Laser AssistedCataract Surgery
• Individual steps of laser assisted cataract surgery (LACS)– Anterior capsulotomy– Nuclear fragmentation– Corneal incisions
• Hypothetical benefits
• Discuss the current evidence base– very early days in adoption of LACS– further discussion of clinical
impression
Agenda
Does LACS:
• Improve precision and reproducibility?
• Improve safety?
• Improve refractive outcomes?
Questions
• Are the benefits statistically significant:
– Result unlikely to occur by chance– Does not mean result is important or
meaningful
• Are the benefits clinically or practically significant
• Is the benefit worth the extra time, cost and effort
Assessing evidence for new technology
• High resolution anterior segment imaging coupled to femtosecond laser
• Anterior capsulotomy
• Nuclear fragmentation
• Corneal incisions (primary, secondary and arcuate incisions)
Capabilities of LenSx laser
Anterior Capsulotomy
• Perform capsulotomy safely and completely, resistant to tearing
• Central, circular and reproducible– anteroposterior effective lens position– lateral centration– IOL calculations
• Predictably overlap IOL edge by 0.5mm
Anterior Capsulotomy
Anterior Capsulotomy
• Most striking feature of day 1 appearance
• Published evidence?
Anterior Capsulotomy
• Nagy
– 100% of anterior capsulotomies within 0.25mm vs 10% of manual
Anterior Capsulotomy
• Tackman, Friedman– less deviation
from intended diameter
– increased circularity
Anterior Capsulotomy
• Zoltan Nagy– Series of studies– Less IOL tilt and decentration– Better IOL-anterior capsule overlap– Decreased higher order aberrations
• Clinical significance?– No definite improved refractive result
(sphere, cylinder or unaided visual acuity)– Longer term studies required– Subgroup analysis required
Nuclear Fragmentation
• Effectively disassemble the nucleus
• Safety: protection of posterior capsule
• Safety: reduction in total phaco power and protection of corneal endothelium
Femtosecond nuclear fragmentation
• No reports of femtosecond laser direct damage to posterior capsule
• Offset from posterior capsule on imaging appears to be effective in preventing this
Nuclear fragmentation- safety
• Reducing need to go deeper with phaco tip may reduce risk of PC rupture
• 0.31% PC rupture rate lower than reported incidence of 0.53% - 2.7% in manual surgery
Nuclear fragmentation- safety
• Decreased total phaco energy confirmed to statistically significant level in multiple studies
• Close to 50% reduction in both total phaco energy and phaco time
• May reduce damage tocorneal endothelium
• May reduce potential forinflammation andcorneal burns
Nuclear fragmentation- safety
• Statistically significant reduction in phaco energy in all grades of cataract
• No studies yet to confirm reduction in endothelial cell loss. Further long term studies required.
• May be particularly important in patients with Fuch’s dystrophy
• Younger patients
Endothelial protection
Corneal incisions
Ability to customise reproducible, multiplanar corneal wounds shown in multiple studies
Corneal incisions
• Reproduciblewounds may allowmore consistentsurgically inducedastigmatism
• No large studiespublishedat this stage
Corneal incisions
• Endophthalmitis a rare but devastating complication
• Well constructed clear corneal wounds may reduce the risk of endophthalmitis
• Difficult to study: incidence 0.13%
• A lot of data would be required to prove a benefit in reducing endophthalmitis
Corneal incisions
Latest Results
• In this section, focus on objective current data, not on our clinical impression
• Objective data already demonstrates that LACS is no worse than manual phaco– Short learning curve– Would not have been able to say this about
move from ECCE to phaco in first 12 months– Took until 2001 for first large scale RCT
proving cost effectiveness of phaco vs ECCE
Conclusions
• New technology– experience rising very rapidly– 30,000 cases, almost all in the last 12
months
• Data demonstrating statistically significant benefit in a number of areas– at this stage relatively little definite clinically
significant data– large number of studies currently underway– longer term studies, eg endothelial cell loss
Conclusions
• Positive initial impressions, not discouraged by:– inability to immediately have clinically
significant evidence base– new complications– increases in cost
• As technology and techniques mature, history suggests:– complications decrease– equipment costs reduce with widespread
adoption– outcomes and efficiencies improve– Other technologies develop
Conclusions
EastwoodEye Surgery
Laser Refractive Cataract Surgery
Provides Image –guided, surgeon control to perform:– Anterior capsulotomy– Lens fragmentation– Corneal incisions
4 systems currently in development
EastwoodEye Surgery
Laser Refractive Cataract Surgery
Possible Advantages– Automates steps of cataract surgery– Improved corneal incisions & astigmatism
control– Improved capsulotomy for effective lens
positioning– Less phaco energy and endothelial cell loss
EastwoodEye Surgery
Laser Refractive Cataract Surgery
Disadvantages– Topical anaesthesia– Cost– Limitations
Small pupil
Corneal opacity
Dense cataract
Keratoconus
EastwoodEye Surgery
Laser Refractive Cataract Surgery
Exciting technology and future is bright
Still in its infancy and benefits unclear
Requires better safety data & research
Costs must be addressed
Secondary advances may revolutionise cataract surgery
Thank You