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Image-guided femtosecond laser technique enables precise capsulorrhexis enlargement
The result is a 360° overlap of the IOL optic, with no major capsular bag shrinkage or posterior capsule opacification.
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An image-guided femtosecond laser technique is an option for enlarging a small anterior capsulorrhexis, according to a study.
A small capsulorrhexis can cause capsular bag shrinkage, IOL decentration and patient dissatisfaction. Manual capsulorrhexis enlargement techniques are challenging and frequently yield unsatisfactory results, according to the study authors.
H. Burkhard Dick, MD, PhD, and Tim Schultz, MD, described the femtosecond laser technique in a study published in the Journal of Cataract and Refractive Surgery. It was performed with the Catalys Precision Laser System (Abbott Medical Optics) in five patients whose capsulorrhexis was smaller than 4 mm. All patients received an IOL that was 6 mm in diameter.
H. Burkhard Dick
“[The technique] offers the advantages of a laser-generated capsulotomy: perfection of laser-generated capsulotomy in size, position aligned to the individual IOL optic location, and circularity and shape in a closed system,” Dick told Ocular Surgery News.
Enlargement technique
After IOL implantation, the ophthalmic viscosurgical device is removed from in front of and behind the IOL. The incisions are sealed with balanced salt solution.
After docking the patient and laser system, a sterile suction ring is placed centrally on the sclera. Adjustments are made, vacuum is enabled, and the suction ring is filled with balanced salt solution. The ring is then connected to the disposable lens attached to the laser system.
The system’s three-dimensional spectral-domain optical coherence tomography feature is used to visualize the anterior segment. Using the infrared camera, the anterior rescue capsulotomy is centered manually on the IOL. In the axial and sagittal OCT view, the opened anterior capsule is identified and the treatment zone is adjusted.
“[The technique] also takes into account any tilt of the eye or the IOL and positions the capsulotomy accordingly because of the 3-D SD-OCT,” Dick said.
After the procedure, the additional capsule ring is removed and sent for histologic evaluation. The corneal incisions are hydrated with balanced salt solution.
“[The technique] slightly increases time by a minute up to a minute and a half because of the need to re-dock and re-scan. Time for cutting the capsulotomy is about 2 seconds maximum,” Dick said.
Results and observations
The authors were able to identify and target the anterior capsule in all cases. No cases of suction loss were reported.
Postoperatively, visual acuity improved significantly in all cases, and there were no cases of IOP elevation. No damage to the IOL was visible. No cases of extensive capsular bag shrinkage or posterior capsule opacification were reported at 1-month follow-up. The capsulotomy completely overlapped the IOL optic in all cases.
No cases of glare sensitivity or light sensations were reported. Mean deviation from the targeted capsulotomy diameter of extracted capsule rings was –55 µm.
“The surgeon can start with a manual capsulorrhexis and ‘finalize’ the case with a perfect capsulotomy using the laser for the final capsulotomy,” Dick said.
The laser-assisted technique will be applicable to future IOL designs that might incorporate new shapes or features, such as bumps in the capsulotomy edge for alignment or IOL fixation, that cannot be accommodated manually, Dick said.
The technique can be performed before or after IOL implantation and has other advantages, according to Dick.
“Especially after IOL implantation, it takes into account the individual position of the IOL in the capsular bag, which sometimes is not the geometric center of the capsular bag. Therefore, 360° capsular overlap is guaranteed,” Dick said. “If the IOL has to be positioned at a certain location as in a toric IOL alignment to the axis, the IOL still would be covered completely.” – by Matt Hasson
Reference:
Dick HB, et al. J Cataract Refract Surg. 2014;doi:10.1016/j.jcrs.2014.08.021.For more information:
H. Burkhard Dick, MD, PhD, can be reached at University Eye Clinic, University of Bochum, In der Schornau 23-25, 44892 Bochum, Germany; 49-234-299-3100; email: burkhard.dick@kk-bochum.de.Disclosure: Dick is a paid consultant to Abbott Medical Optics.