Clinical Comparison of Effect of Sub-One Second Femtosecond Laser Capsulotomy on Capsulotomy Irregularities
Purpose
To evaluate the frequency of anterior capsule irregularities when using a femtosecond laser to create the anterior capsulotomy and to compare the effect of different vertical spacing and incision depth settings on the quality and speed of the laser capsulotomy.
Methods
2466 consecutive cases, performed by 5 surgeons, were examined from November 2013 to August 2014. Cases were excluded only if the laser treatment could not be performed or completed. Cases were grouped for vertical spacing settings of 6, 10, or 15 µm. The incision depth was 600 µm for the 6 µm and 10 µm groups and 400 µm for the 15 µm group. Capsulotomy edge irregularities (slivers, tags, tongues) visible under the operating microscope were recorded. The rates were examined for the whole cohort, regardless of the complexity of the case. Statistical significance was determined via chi-squared analysis.
Results
For the whole cohort, the group using the standard vertical spacing of 10 µm with a 600 µm incision depth, the capsulotomy irregularity rate was 9.1% (112/1238 cases) versus 1.3% (14/1124) for the 15 µm group. A small group with vertical spacing of 6 µm was found to have an irregularity rate of 17% (18/104 cases) and was discontinued due to the high rate. These differences were statistically significant. Anterior capsule tear rates were also noted to be lower in the 15 μm group.
Conclusion
Increasing the vertical spacing setting decreased the rate of capsular edge irregularities. Also, decreasing the incision depth and increasing the vertical spacing resulted in a decreased capsulotomy treatment time of 0.7 seconds. The faster capsulotomy may decrease the effect of patient movement and result in a more predictable capsulotomy.