I saw a patient recently who had femtosecond laser assisted cataract surgery a month prior by an unknown surgeon. The patient had a perfectly round capsulorhexis and the IOL was nicely centered, but she was seeking a second opinion because of a refractive surprise. She wanted a plano result but ended up myopic and because she has a multifocal IOL, this proved problematic.
Her fix is relatively easy since we can simply perform LASIK for this low degree of residual myopia and astigmatism and give her the desired plano refractive outcome. When I examined her at the slit lamp, I noted that her laser-made phaco incision was completely avascular and did not nick the limbal vessels. There was a 1 mm gap between her incision and the limbal vessels. This means weaker and slower healing. The femtosecond laser can be adjusted so that the incision is placed appropriately to nick the limbal vessels. And certainly when using traditional or diamond keratomes, the same principal applies.
Click below to review the critical keys to making phaco incisions:
FLACs incisions leak because they are defective at the internal opening. The fact that they are more anterior doesn’t help and causes more endothelial damage when you do phaco. That’s why only a small percentage of FLACs surgeons actually use the laser to make the incisions. They are awful.
Acta Ophthalmol. 2018 Jun;96(4):e510-e514. doi: 10.1111/aos.13634. Epub 2017 Nov 30.
Clinical and ex vivo laboratory comparison of the self-sealing properties and dimensional stability between the femtosecond laser and manual clear corneal incisions.
Kojima T1, Takagi M1, Ichikawa K1, Horai R2, Sakai Y3, Tanaka Y2, Tamaoki A4,5, Ichikawa K3.
Author information
Abstract
PURPOSE:
To compare the self-sealing features and dimensional stability between the femtosecond laser (FL) and manual knife corneal incision.
METHODS:
For the clinical study, 29 consecutive eyes from 29 patients and 28 eyes from 28 patients who underwent cataract surgery with FL corneal incision and manual knife incision, respectively, were enrolled. Immediately after cataract surgery, the self-sealing features of the corneal incisions were evaluated. Scanning electron microscopy (SEM) images were obtained. For the experimental study, clear corneal incisions with a knife or FL with different energy settings (3, 6 and 9 μJ) were created in fresh porcine eyes, followed by a stress test. The incision width was measured before and after the stress test.
RESULTS:
In the clinical study, the knife group had a higher self-sealing score (0.60 ± 0.49 points) than the FL group (0.17 ± 0.38 points). In the experimental study, the deformation rate in the knife incision (5.04 ± 1.93) was significantly lower than that in the FL with any energy. The deformation rate in the 9 μJ (12.98 ± 2.76) was significantly higher than in the 3 μJ (8.54 ± 2.38) and 6 μJ (8.82 ± 2.85) FL energies. Scanning electron microscopy (SEM) images revealed that the corneal stromal surface of the knife incision was smoother than that of the FL. Higher energy FL showed more irregular surfaces.
CONCLUSION:
Higher FL energy tended to widen a clear corneal incision when mechanical stress was applied. The histological differences at the inner tunnel surface may cause differences in wound stability of the corneal incision.
thanks for the input and perspective. At this point, I certainly prefer a diamond-made incision to a femtosecond laser incision. And that is an interesting study of which i was not aware.
I completely agree with Dr Safran. I have found that even utilizing a blade, some incisions are not as watertight as I’d like. It led me to explore alternate ways of sealing the wound without always having to suture or use an expensive sealant. Using a minimal amount of viscoelastic to “caulk” the inside portion of the incision has been very successful and easy. Please view the link.
https://eyetube.net/series/eyetube-journal-club/episode-6-using-a-dispersive-ovd-inside-a-clear-corneal-incision-to-seal-it/
excellent points — and a great video. thanks for sharing it with our readers