CLEAR LENS EXCHANGE

Clear lens exchange (CLE) may be indicated for some children, but posterior capsular opacification (PCO) and refractive changes as young eyes grow are challenges. Devices and techniques that prevent PCO, and intraocular lenses (IOLs) with interchangeable optics could make the procedure safer, Ioannis G Pallikaris MD, PhD told the 2015 American Society of Cataract and Refractive Surgery Symposium in San Diego, USA.

Generally, clear lens extraction is considered for myopia of -10 dioptres or more, and hyperopia of +7 dioptres or more, Prof Pallikaris noted. In children, CLE may be indicated for severe anisometropia or ametropia with neurobehavioural disorders, peripheral lens opacities despite a clear central crystalline lens, and spectacle and contact lens intolerance. It may also be useful to reduce elevated pressure in eyes with high hyperopia and short axial length, and to treat lenticular disorders including Marfan’s syndrome, spherophakia and lenticonus.

CLE contraindications include retinal disease, with retinal detachment a higher risk with high myopia, as well as glaucoma with visual field loss and amblyopia, Prof Pallikaris said. Systemic conditions including diabetes with eye signs or inadequate control, rheumatoid arthritis with Sjogren syndrome, pathologic dry eye, lupus and AIDS are also contraindications. Patients medicated for clinical depression may also be poor candidates as they may not respond well to unintended outcomes or complications, he added.

CLE advantages include leaving the cornea mostly untouched and eliminating future cataracts, Prof Pallikaris noted. However, in children PCO is almost a certainty and refractive changes will occur as the eye grows.

PREVENT COMPLICATIONS

Several approaches may help prevent these complications, Prof Pallikaris said. These include primary posterior capsulorhexis, and a peripheral capsule reconstructor he designed that may help prevent PCO by creating a barrier to cell proliferation across the posterior capsule. The device has been successfully tested with three-piece and one-piece conventional lenses, as well as the Tassignon bag-in-lens.

“All of these are very well centred on this peripheral ring, and is easy to rotate, which is very important with a toric IOL.”

Refractive stability may be enhanced with a multicomponent IOL with a base rear optic inside the bag and a removable second optic outside the bag, Prof Pallikaris said. This would make it easier to exchange the optic as the patient’s prescription changes, negating the need to completely explant the lens from the fibrotic capsule. The concept has been tested successfully in Prof Pallikaris’ Institute of Vision and Optics at the University of Crete, Greece, he said.

Ioannis G Pallikaris: pallikaris@dunyagoz.com