Shin Yamane MD
A minimally invasive procedure requiring no suturing or glue makes it possible to stabilise a three-piece intraocular lens (IOL) in the posterior chamber position even when the chamber itself is badly damaged, Shin Yamane MD told the 2017 American Society of Cataract and Refractive Surgery Symposium in Los Angeles, USA.
The procedure provides stable, significantly improved vision in eyes with aphakia, dislocated IOLs or subluxated crystalline lenses without the need for a large scleral incision to insert and suture or glue the lens in place.
The procedure involves inserting the lens through a standard corneal incision. The sclera is then penetrated by two thin-walled needles at a shallow downward angle running tangentially into the globe toward the haptic ends. The haptic ends are captured in the needle lumens and pulled simultaneously through the scleral tunnel.
Outside the globe, the haptic ends are dried and flanged using a cautery device, increasing their end diameter from about 0.15mm to about 0.3mm. The flange is then pushed back into the scleral tunnel, which may be slightly widened at the entrance to accommodate the flange, which is too wide to be pulled back through the rest of the tunnel.
When the scleral wounds heal, the IOL is held firmly in place, resulting in stable, significantly improved visual acuity (VA) with few complications and minimal endothelial cell loss, said Dr Yamane, of Yokohama City University Medical Centre, Japan.
GOOD POSITIONING
In a study involving 137 eyes in 134 patients, four different three-piece lens designs were inserted. Three months after surgery, mean best corrected visual acuity improved to 0.12±0.34 logMAR, or a little worse than 20/25, from a pre-operative mean of 0.33±0.53, or a little worse than 20/40.
Mean endothelial cell counts fell from 2,341±481 to 2,243±488, a decline of about 4.2%. Mean lens tilt was 3.29±2.51 degrees, indicating good positioning. Follow-up at six, 12 and 24 months found VA and endothelial cell counts stable, with no lenses losing fixation.
The most common early complications were vitreous haemorrhage at 3.6%, hypotony and intraocular pressure elevation at 2.2% each and corneal oedema at 0.7%. Late complications were iris capture of the IOL at 5.8%, and cystoid macular oedema and IOP elevation at 2.2% each.
Dr Yamane emphasised the need for proper technique, including using thin-wall needles, creating the scleral wounds in the proper positions and inserting the needles at the proper angle. He plans to develop instruments to help guide needle insertion.
“The procedure is simple but not easy,” he said.
Shin Yamane: shinyama@yokohama-cu.ac.jp
