Visual performance is better with implantable collamer lens
A Study was conducted to compare the visual performance between the iris-fixated phakic intraocular len (pIOL) and implantable collamer len (ICL) to correct high myopia.

24 eyes had iris-fixated pIOL implantation while 24 eyes had ICL implantation. The best-corrected visual acuity (BCVA) and the improper visual acuity distance (UDVA) between the iris-fixed pIOL and ICL groups were compared at the six months follow-up. The Objective Scatter Index, MTF and ocular aberrations were carried out in order to assess the post-operative visual properties between the two groups.

--No significant difference was found in UDVA, BCVA, and spherical equivalent between the iris-fixated pIOL and ICL groups.

--Six months after surgery, the following values were significantly higher in the ICL group than in the iris-fixated pIOL group: MTF cutoff, strehl ratio and optical quality analysis system values at contrasts of 9%, 20%, and 100%.

--The OSI in the iris-fixated pIOL group was higher than in the ICL group 6 months after surgery.

--All high-order aberrations were slightly more severe in the iris-fixated pIOL group than in the ICL group 6 months after surgery, although only trefoil differed significantly in this regard.

In short, both iris-fixed lenses and ICLs can be very acute in terms of vision. In MTF-associated metrics, ICLs provide higher visual performance and lead to fewer intraocular light diffusion than iris-fixed pIOLs.