Purpose:
A modified implantable collamer lens (ICL) with a central hole (diameter, 0.36 mm), a "KS-AquaPORT (STAAR SURGICAL)", was created to improve aqueous humour circulation. The aim of this study was to investigate the fluid dynamic characteristics of aqueous humour in a KS-AquaPORT using computational fluid dynamics, and effect of laser iridotomy (LI).
Methods:
Fluid dynamics simulation using an ICL was performed with thermal-hydraulic analysis software FloEFD V5 (Mentor Graphics Corp.). For the simulation, three-dimensional eye models based on a modified Liou-Brennan model eye with conventional ICL (Model ICM, STAAR SURGICAL) and a KS-AquaPORT were used. Both ICLs were -9.0 diopters (D) and 12.0 mm in length, with an optic of 5.5 mm. The vaulting was 0.50 mm. The quantity of aqueous humour produced by the ciliary body was set at 2.80 μl/min. Flow distribution between the anterior surface of the crystalline lens and the posterior surface of the ICL was also calculated, and trajectory analysis was performed.
Results:
The flow velocity 0.25 mm in front of the centre of the crystalline lens was 1.48×10-1 mm/sec for the KS-AquaPORT without LI, 1.20×10-1 mm/sec for the KS-AquaPORT with LI 250 μm, and 3.60x10-4 mm/sec for the conventional ICL with LI 250 μm. Outward flow from the hole in the KS-AquaPORT was confirmed by trajectory analysis.
Conclusions:
These results suggest that use of the KS-AquaPORT improve aqueous humour circulation, preventing secondary cataracts and eliminating the need for LI.
Keywords: refractive surgery: phakic IOL • intraocular lens • aqueous