Posters

Lens capsulotomy tensile strength and elasticity with the Ziemer LDV Z8 femtosecond laser

Poster Details

First Author: G.Williams SINGAPORE

Co Author(s):    B. George   Y. Wong   H. Ang   V. Tay   D. Tan   J. Mehta     

Abstract Details

Purpose:

To determine the strength and elasticity of the lens capsulotomy with the Ziemer LDV Z8 femtosecond laser platform with the nucleus intact or expressed.

Setting:

The Singapore Eye Research Institute experimental animal facility.

Methods:

Capsulotomies at 4, 5 or 6mm diameter were created in fresh (<6 hours post-enucleation) porcine globes (n=18). Lenses were removed en bloc with the nucleus intact or by visco-dissection and sized with Image J. Lens capsule strength (mN) and stretching ratios (capsulotomy size mm + displacement mm/capsulotomy size) were determined by the single column universal testing system (Instron).

Results:

Lens capsulotomy elastic recoil resulted in an aperture 1.34-1.81mm larger with the nucleus intact, reducing to 0.22-0.48mm following removal. There was an incremental increase in capsule tension strength from 4-6mm capsulotomy with intact nucleus (83.18 vs. 119.7 vs. 139.7mN, p=0.001) and following removal (97.98 vs. 102.1 vs. 125.7 7, p=0.03). A corresponding increase was also observed in the stretching ratios (2.09 vs. 2.18 vs. 2.53, p<0.001) with intact nucleus. There was no difference in strength at each capsulotomy size, however a reduction in the stretching ratio was observed at 6mm capsulotomy following nucleus removal (2.53 vs. 1.98, p<0.0001).

Conclusions:

Capsulotomy strength and elasticity have been shown to vary among femtosecond platforms. We found that the Ziemer LDV Z8, employing an energy pulse in the nanojoule range, created stronger and more compliant capsulotomies with increased size. The implications for lens removal and IOL implantation need to be considered with the potentially smaller capsulotomies achievable by femtosecond laser, especially following nucleus removal.

Financial Disclosure:

One or more of the authors travel has been funded, fully or partially, by a company producing, developing or supplying the product or procedure presented