LUMENIS SELECTA - Precautions; Energy Use

Posterior Capsulotomy—1064 nm Nd:YAG  109
Selecta
PBL200051, Rev J
• patients with vascularization of any target membrane are at
increased risk of bleeding
Precautions
Targeting
Focus the unit in accordance with the description provided in the Operation
section of this manual. In dual aiming beam systems such as Selecta, the
Nd:YAG beam extends beyond the diode beams, so there is an increased
probability of Nd:YAG beam impingement of the iris. The diode aiming
beam focus spot is longitudinally offset up to a maximum of 350 microns in
front of the Nd:YAG beam. Therefore, the operator should not activate the
laser without verifying that the aiming and treatment beams are appropriately
coincident and properly targeted. Verify that the treatment beam path is not
obstructed by other nontarget tissues. Care should be taken when working at
the iris margin or at a wide angle to the patient’s visual axis.
The aiming/treatment beam offset can be adjusted using the Selecta posterior
offset control. With the offset control set at 100 microns, Selecta delivers a
preset offset equal to 100 microns in air.
Energy use
To reduce risk of damage to nontarget tissues, the lowest possible energy level
should be used, beginning with 1-2 mJ and increasing the energy as required.
The burst-mode capability should not be used initially for capsule dissection.
Burst mode should be used only when increasing levels of single shot energy
have not been successful in opening the capsule. If the capsule is tough or
scarred, higher energy shots may be required. It is recommended that the
increase be in 1-2 mJ steps. The clinical experience indicates that the mean
power level used is 2.7 mJ, and 97% of the subjects were treated at less than
5 mJ.
The minimum number of shots required to obtain an adequate opening
should be used. The mean is 40 shots, although greater than 100 shots may be
required for membranous tissue. The risk of IOL damage increases with
increasing energy level and number of shots used. Once an opening has been
established, it is enlarged, as necessary, until the capsulotomy is adequate.
In the presence of edematous, clouded, scarred or irregular astigmatic corneas,
the laser beam may be less effective, necessitating higher energy settings to
obtain optical breakdown. Medical judgment must be used to determine
whether the corneal condition in such circumstances contraindicates laser
posterior capsulotomy.