Komplikationen moderner Intraokularlinsen (IOL)

[Intraocular lens explantation and retroiridal iris claw lens implantation via the pars plana : Video article]

OBJECTIVE OF SURGERY

The aim is the explantation of an intraocular lens (IOL) due to dislocation into the vitreous cavity with subsequent secondary implantation of a retropupillary iris claw IOL via the pars plana without creating a large corneal incision. The aim of the operative technique is to avoid corneal astigmatism after secondary IOL implantation, faster recovery of visual acuity and reduction of invasive maneuvers in the anterior chamber.

INDICATIONS

The surgery is indicated by an in-the-bag dislocation of a posterior chamber lens into the vitreous cavity without the possibility of refixation due to zonulopathy.

CONTRAINDICATIONS

Contraindications are extensive iris stromal defects, iritis, scleromalacia, ischemic retinopathies.

SURGICAL TECHNIQUE

The technique consists of explantation of the IOL during a standard pars plana vitrectomy (20 gauge) with an extended sclerotomy and subsequent secondary implantation of a retropupillary iris claw IOL using the same sclerotomy. The operation video is available online.

FOLLOW-UP

Treatment is carried out with local steroids and antibiotic eyedrops for 3 weeks. In the case of a corneal suture, removal is recommended after 14 days.

EVIDENCE

The implantation of a retroiridal iris claw lens is an established procedure. The introduction via the pars plana in the presented form is a first description.

Calculation of iris-claw IOL power for correction of late in-the-bag IOL complex dislocation

Background

To assess the constants and formula for aphakia correction with iris-claw IOLs to achieve the best refractive status in cases of late in-the-bag IOL complex dislocation.

Methods

A literature search was performed. The following data were obtained: Iris-claw IOL model, Iridal or retroiridal enclavation, A-constant, ultrasound or optical biometry, formula employed and refractive outcomes. Acceptable emmetropia was considered if the resulting spherical equivalent (SE) was within ±1.00 D.

Results

The majority of the studies used SRK/T formula (66.6%). The 88.9% of the reports obtained a SE within ±1.00 D. Using A-115 for ultrasound biometry and A-115.7 for optical biometry and SRK/T formula, the emmetropia (±1.00 D) of SE, was able to get near 100% of reported cases over the pupil implantation. However, the emmetropia decreased to 80% when the enclavation is retropupilar using the same formula. The A-constant can vary from 116.7 to 117.5 for retropupilar enclavation.

Conclusions

Using A-115 for ultrasound biometry and A-115.7 for optical biometry and SRK/T formula, ±1.00 D of SE, is able to get near 100% of cases. Nevertheless, ±1.00 D of SE decreased to 80% of the cases when the enclavation is retropupilar.