Femtosecond laser-assisted cataract surgery (FLACS) and subluxated lenses

Femtosecond laser-assisted cataract surgery (FLACS) can simplify removal of subluxated lenses in mild to moderate cases, Armando Crema MD, Rio de Janeiro, Brazil, told the 2015 American Society of Cataract and Refractive Surgery Symposium in San Diego, USA.

While laser technology is often viewed as a way to improve refractive outcomes with premium lenses, it offers so much of an advantage in fragile eyes that complex cases make up 26 per cent of laser-assisted cataract cases Dr Crema performs. Pre-cutting the anterior capsule and pre-fragmenting the lens reduces the amount of intraocular manipulation required to remove the cataract, putting less stress on already weakened zonules and supporting tissues, he noted.

“Subluxated lenses are a good indication for use of this new technology,” he said.

As long as the lens is not displaced too far from the pupil centre, the laser can do the anterior capsulotomy and pre-fragment the lens, Dr Crema said. He showed a case of a patient with Marfan’s syndrome in which the capsulotomy and lens fragmentation were perfectly done by the femtosecond laser, greatly reducing the force needed to remove the lens in a very fragile eye. (Figure 1)

Because the lens was off centre in one eye with a severe subluxation, the area of lens fragmentation was reduced, but this still resulted in less mechanical and phaco energy to remove the lens.

Dr Crema noted, however, that a free anterior capsulotomy is essential, so the cut should be checked for microtags before beginning the case. Corneal opacities and poor dilation may be contraindications for using laser-assisted cataract technology as they may prevent adequate lens treatment.

Dr Crema typically uses a pre-chopper to separate pre-fragmented lenses, and when possible hydrodissects them to the anterior chamber before aspirating. This generally leaves the capsular bag intact and limits any damage to weakened zonules. In traumatic subluxation cases, he has successfully removed lenses even with some zonules torn without further damage to intact zonules. (Figure 2)

An endocapsular tension ring may then be inserted in the bag and the bag centred and anchored to the sclera with a stitch. This allows the replacement lens to be implanted in the bag. Dr Crema noted that the anterior capsulotomy easily done by LACS technology also contributes to a good outcome in these cases because it enables implantation of an endocapsular tension ring and centration of the capsular bag and lens implant.

Dr Crema reported several cases of well-centred lenses and post-surgery best corrected vision of 20/20 in patients 20/80 to 20/100 before surgery due to a located crystalline lens. However, in severe cases, where the lens is too far away from centre, the laser cannot cut an adequate capsulotomy, that will be decentred and very peripherally, leaving small anterior capsule margins (Figure 3). The pros and cons of using a femtosecond laser should be evaluated in each case, he said.

Armando Crema:
acrema@openlink.com.br