A new technique for Nd:YAG laser posterior capsulotomy

[Posterior YAG capsulotomy: selection of the application pattern]

BACKGROUND

The posterior neodymium-yttrium-aluminum-garnet laser capsulotomy is an established and simple method with a low complication rate for the treatment of secondary cataracts; however, the risk of intraocular pressure elevation, pit marks of the intraocular lens (IOL), anterior hyaloid damage, cystoid macular edema and retinal detachment may increase with high pulse number, pulse energy, and total energy.

PURPOSE

The optimization potential of the method through a rational choice of the laser pattern and the strategy, taking into account the mechanical properties of the posterior capsule and the anatomical features of the retrolental region, is shown.

MATERIAL AND METHODS

The article provides a literature review with own clinical observations and a geometric representation.

RESULTS

The efficiency of a laser pattern is examined with a constant capsulotomy length: The largest opening can be reached with the U‑pattern, which is followed by the +, T, H, V, O and spiral patterns in decreasing order. When estimating the size of the opening, its incircle is of particular functional importance. If the ability of the posterior capsule to tear spontaneously, which is predetermined by its anatomical and mechanical properties, is taken into account when choosing the application pattern and the laser strategy, the efficiency of the method increases.

CONCLUSION

An efficient technique is not only determined by an adapted defocusing and a minimum possible individual pulse energy setting but also characterized by the lowest possible total energy consumption if the necessary opening size is achieved by the smallest number of pulses. Taking into account the individual retrolental anatomical conditions and the mechanical properties of the NS membrane can contribute to the gentle implementation of a YAG capsulotomy.

Comparison of two Nd:YAG laser posterior capsulotomy: cruciate pattern vs circular pattern with vitreous strand cutting

AIM

To investigate the effects and safety of neodymium: yttrium-aluminium-garnet (Nd:YAG) laser posterior capsulotomy with vitreous strand cutting.

METHODS

A total of 40 eyes of 37 patients with symptomatic posterior capsular opacity (PCO) were included in this prospective randomized study and were randomly subjected to either cruciate pattern or round pattern Nd:YAG posterior capsulotomy with vitreous strand cutting (modified round pattern). The best corrected visual acuity (BCVA), intraocular pressure (IOP), refractive error, endothelial cell count (ECC), anterior segment parameters, including anterior chamber depth (ACD) and anterior chamber angle (ACA) were measured before and 1mo after the laser posterior capsulotomy.

RESULTS

In both groups, the BCVA improved significantly (P<0.001 for the modified round pattern group, P=0.001 for the cruciate pattern group); the IOP and ECC did not significantly change. The ACD significantly decreased (P<0.001 for both) and the ACA significantly increased (P=0.001 for the modified round pattern group and P=0.034 for the cruciate group). The extent of changes in these parameters was not significantly different between the groups.

CONCLUSION

Modified round pattern Nd:YAG laser posterior capsulotomy is an effective and safe method for the treatment of PCO. This method significantly changes the ACD and ACA, but the change in refraction is not significant. Modified round pattern Nd:YAG laser posterior capsulotomy can be considered a good alternative procedure in patients with symptomatic PCO.