Abstract
Purpose: :
Understanding and evaluating the biomechanical behaviour of artificial intraocular lenses presents a significant challenge, the solution of which may lie in high resolution anterior-segment imaging. The aim of the study is to use this technology to assess the anterior segment in rabbits after IOL surgery (monofocal IOL implantation, lens refilling).
Methods: :
High-resolution magnetic resonance ocular images were acquired (7.1 Tesla, ClinScan, Bruker Bioscan) using a rat brain coil and a standard spin-echo radio-frequency pulse sequence in rabbits after lens-based refractive surgery in combination with an intra-operative antiproliferative treatment to prevent LEC proliferation. Single slices and 3D reconstructions were used to assess the anterior eye segment up to 3 years postop.
Results: :
IOL placement (tilting, centration) and the retroiridian haptic configuration were evaluated in 3 dimensions. Lens capsule and implant were in close contact 1 year after implantation, whereas the capsular bag had experienced retroiridial expansion in a case of extensive excentric Soemmering's ring formation. The spatial arrangement (radius of curvature, axial and equatorial diameters) of refilled lenses was visualized by in vivo micro-MRI. In partially filled eyes, the capsular bag and silicon polymer were separated; however, in completely refilled eyes, the capsule and homogenous silicone polymer came in close contact with no visible interface. A different radius of curvature was found especially in the equatorial region between the refilled lens (3 years postop) compared to the crystalline lens of the contralateral eye (see figure).
Keywords: anterior segment • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • accomodation