News in Review
The Ideal Capsulotomy?
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If a femtosecond laser capsulotomy were as close to perfect as technologically possible, what would be its size and location on the capsular bag? Ideally, it would be 5.25 mm wide and centered on the optical axis of the crystalline lens, concluded Mark Packer, MD, FACS, CPI, and colleagues in a recent publication.1 Dr. Packer is associate clinical professor of ophthalmology at Oregon Health & Sciences University, in Portland.
The authors postulate that this configuration would:
- Place the capsulotomy edge on the thickest part of the bag, to minimize the risk of capsular tears
- Ensure that the capsulotomy and the IOL are concentric, thus allowing the capsule rim to overlap the IOL evenly for 360 degrees, to prevent posterior capsular opacification
- Optimally and stably position the IOL in the bag, to possibly achieve a more predictable refractive outcome
Methods and results. To reach their biomechanical conclusions, the research group built an apparatus to test the strength and elasticity of 49 porcine capsular bags that had been incised with either a 5.0-mm manual continuous curvilinear capsulorrhexis (CCC) or a laser capsulotomy of between 4.0 and 5.5 mm.
In the CCC eyes, the anterior capsular rims broke with significantly less mean force (p < .05), and their mean elongation at breaking point was significantly smaller (p < .0001) than in the laser eyes. Although the researchers found that a 5.5-mm capsulotomy would be even stronger, they chose 5.25 mm as an ideal size so as to place the laser capsulotomy in the histologically thickest region of the capsule, Dr. Packer said.
—Linda Roach
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1 Packer M et al. Br J Ophthalmol. March 31, 2015. [Epub ahead of print.]
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Relevant financial disclosures—Dr. Packer: Alcon: C; Bausch + Lomb: C; Lensar: C,O.
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