Ciliary sulcus shape may help guide IOL suture fixation

This study explores whether assessment of the ciliary sulcus and the surrounding tissue after intracapsular cataract extraction (ICCE) can help determine the correct suture site for IOL suture fixation.

Study design

This prospective case series used ultrasound biomicroscopy (UBM) to examine the ciliary sulcus of 16 eyes after ICCE. The authors also performed an endoscopic observation of the sulcus of 150 eyes to identify external anatomic landmarks that correspond with the location of the ciliary sulcus in eyes undergoing IOL suture fixation.

Outcomes

In ab interno ciliary sulcus suture fixation, a needle passing through the deepest part of the sulcus parallel to the posterior iris will emerge 2.4 mm behind the posterior surgical limbus. In 128 eyes with endoscopically confirmed straight needle placement through the deepest part of the sulcus, the needle emerged 2.5 mm behind the posterior surgical limbus; in 22 eyes with endoscopically confirmed curved needle placement, the needle merged 2.0 mm behind. 

Curved needle placement was less consistent than straight needle placement. Pars plana fixation should be performed 3.0 mm behind the posterior surgical limbus.

Limitations

Because the study does not explore the baseline biometry of the eyes being measured, it is impossible to know the general applicability of these measurements.  The calculation also depends on the average pars plicata length.

Clinical significance

This study explains in vivo ciliary sulcus anatomy, which is important for cataract surgeons. More advanced biometry may ultimately help calculate effective lens position more accurately for in-the-bag IOLs as well.