Theoretical study on the need for laser iridotomy in an implantable collamer lens with a hole using computational fluid dynamics.

PurposeAlthough one of the advantages of the Hole-ICL implantation is that laser iridotomy (LI) is unnecessary, the evidence have not been reported from the viewpoint of aqueous humor circulation. We investigated the effect of laser iridotomy (LI) on the fluid dynamics of aqueous humor in an implantable collamer lens (ICL) with a central hole, that is, a Hole-ICL using computational fluid dynamics.MethodsA fluid dynamics simulation was performed using the thermal-hydraulic analysis software FloEFD (Mentor Graphics Corp.). For the simulation, three-dimensional eye models with a conventional ICL (Model ICM, STAAR SURGICAL) and a Hole-ICL were used. The LI diameters were 250 and 500 μm. The flow distribution between the anterior surface of the crystalline lens and the posterior surface of the ICL was also calculated.ResultsThe flow velocity 0.25 mm in front of the center of the crystalline lens in the Hole-ICL without LI, with LI of 250 μm, and with LI of 500 μm was 1.48 × 10-1 , 1.20 × 10-1 , and 4.52 × 10-2  mm/s, respectively. The flow velocity in the conventional ICL without LI, with LI of 250 μm, and with LI of 500 μm was 1.21 × 10-5 , 3.60 × 10-4 , and 6.33 × 10-4  mm/s, respectively.ConclusionsThese results suggest that there is less need for LI in a posterior chamber phakic intraocular lens with a central hole from the viewpoint of aqueous humor circulation, although the results can be considered only in an ideal condition and further studies are needed to clarify the effect of LI in clinical practice.