Circumventing corneal edema during femtosecond laser lens capsulotomy

Session Details

Session Title: Laser-Assisted Cataract Surgery (Femto and Other Types of Lasers)

Session Date/Time: Monday 12/09/2016 | 14:00-15:30

Paper Time: 14:48

Venue: Hall C3

First Author: : G.Wiliams SINGAPORE

Co Author(s): :    B. George   Y. Wong   G. Yam   M. Ang   S. Tay   J. Mehta     

Abstract Details

Purpose:

To determine the effects of the Ziemer LDV Z8 liquid interface femtosecond laser platform during capsulotomy under different energy settings and in the context of corneal oedema.

Setting:

The Singapore Eye Research Institute experimental animal facility and the Singapore National Eye Centre.

Methods:

Cadaveric porcine eyes harvested at <6 and 24>post hours enucleation to simulate clear and oedematous corneas were evaluated with the Ziemer LDV Z8 femtosecond laser during capsulotomy (5mm diameter, energy 90%, 130% or 150) (n=36). Lens capsules were removed for evaluation by scanning electron microscopy (SEM) and rupture strength was determined by the single column universal testing system (Instron 3343). Following ethical approval, a cohort of 23 patients (median age 70) had lens capsules removed during routine cataract surgery following manual or Z8 capsulotomy and subjected to TUNEL assay.

Results:

There was no difference in the edge morphology or in rupture strength (120, 113 and 118mN at increasing energy, p=NS) in the clear cornea. In human samples, increased TUNEL positive cells were seen at 130% energy, but not at 150% (0.0 manual vs. 0.2 [90%] vs. 2.1 [130%] vs. 0.6%[150%], p<0.05). Only 50% of capsulotomies succeeded at 90% energy in an oedematous cornea. This was abrogated at increased energy (75% completion at 130%, 100% at 150%). Rupture strength in oedematous corneas was not significantly different at 112, 133 and 114mN for 90, 130 and 150% respectively, p=NS).

Conclusions:

Because of the low energy delivered by the Ziemer Z8 platform, even incremental increases in energy appeared to have minimal effect on lens capsule morphology and strength and negligible influence on cell death. Furthermore, increasing energy appears to enhance consistency in the ability to complete a capsulotomy in an oedematous cornea..

Financial Disclosure:

... travel has been funded, fully or partially, by a company producing, developing or supplying the product or procedure presented