Behavior of Generated Gas during Femtosecond Laser Lens Irradiation in Porcine Cadaver Eyes

(1) Background: We investigated the behavior of gas inside a lens and its influence on the lens capsule, which may cause complications by lens irradiation with a femtosecond laser cataract surgery device. (2) Methods: The crystalline lenses of 6-month-old porcine cadaver eyes were observed during laser irradiation. An intraocular endoscope in the vitreous cavity was used to measure the posterior capsule position. Optical coherence tomography measurements of the anterior chamber depth before and after the laser irradiation, as well as measurements of the equatorial perimeter of the extracted lens, were compared with those of the controls. (3) Results: Femtosecond laser-generated gas in the porcine lens was dependent on laser irradiation energy. Increases in the amount of laser irradiation energy caused the generated gas to coalesce, move backwards beyond the laser irradiation site, and expand the lens capsule and posterior capsule. (4) Conclusions: The present results suggest that laser irradiation-induced gas moves in the direction of the posterior capsule beyond the lens irradiation site and expands the lens capsule, which may be involved in the development of capsular block syndrome.

Virtual Eye Simulation: An Aid in Evaluation of Capsular Block Syndrome

Objective: To demonstrate the findings of three consecutive cases of postoperative Capsular Block Syndrome (CBS) diagnosed with the aid of Pentacam virtual eye simulation images. Methods: Observational case series report. Three patients underwent uneventful cataract removal and presented with blurry vision ranging from 4 days to 5 years after the surgeries were performed. Results: In a case of early-onset postoperative CBS, virtual eye simulation images clearly revealed a reduced posterior chamber depth caused by the accumulation of transparent fluid in the area between the intraocular lens and the posterior capsule. In two cases of late-onset postoperative CBS, virtual eye simulation images better visualized the alignment between intraocular lens (IOL) and iris than slit lamp examination and Schiemflug images. All three of the cases underwent neodymium-doped yttrium aluminum garnet (Nd:YAG) laser capsulotomy, and their capsular bag distensions were resolved immediately. The patients with misalignments between IOL and iris experienced more improvement in best-corrected visual acuity as opposed to the one who did not. Conclusion: Virtual eye simulation is found to be a useful way in visualizing misalignment between IOL and iris and assisting diagnoses of both early- and late-onset postoperative capsular block syndrome.