Clinical And Experimental Study Of Iris-Sutured Posterior Chamber Intraocular Lens

Part1Ultrasound Biomicroscopic Analysis of Iris-fixated Foldable Intraocular LensObjective:To observe the position of iris-fixated posterior chamber intraocular lenses (PCIOL) with ultrasound biomicroscopic (UBM), and evaluate the safty of the operation.Methods:17patients (17eyes) who had insufficient posterior capsular support for intraocular lens underwent iris-fixated foldable lens implantation. All the patients were followed up for6months. The preoperative best corrected visual acuity (BCVA), uncorrected visual acuity(UCVA) and BCVA3months after operation were recorded. Differences between postoperative UCVA and preoperative BCVA, and differences between postoperative BCVA and preoperative BCVA were analyzed.6months later, UBM was used to determinate the haptic position in relation to ciliary sulcus and ciliary body, the anterior chamber depth (anterior chamber depth, ACD),lens tilt, relationship of the IOL optic to iris and angle abnormalities in these eyes. Main outcome measures were haptic position, ACD and iris anatomic changes.Results:Preoperative BCVA was (0.49±0.29), postoperative UCVA was (0.50±0.24), postoperative BCVA was (0.66±0.25).There was no statistical difference between postoperative UCVA and preoperative BCVA (t=0.26, P=0.80), postoperative BCVA was better than preoperative BCVA (t=4.97, P<0.01).34haptics of the17IOLs,27(79.4%) were positioned in the ciliary sulcus.5(14.7%) haptics were found over the ciliary processes, and2(5.9%) were over pars plana. Both haptics were in the ciliary sulcus in11eyes of the17eyes (70.6%). The mean (±standard deviation) ACD was(3.84±0.36) mm. No patients were found to have peripheral anterior synechiae, angle abnormalities or tilted lens.Conclusions:Iris-sutured PCIOL haptics were found to be in the ciliary sulcus or over the ciliary body with no lens tilt on UBM analysis. The procedure respects the angle anatomy, and no evidence of angle closure was found. The ACD was similar to that of in-the-bag PCIOLs.This may have implications for surgical technique, IOL power calculations, and postoperative complications.Part2Study of light Transmittance in Iris-Sutured Posterior Chamber Intraocular LensObjective:To observe the changes of iris-fixated posterior chamber intraocular lenses, measure and analyse light transmittance of the optic of those intraocular lenses (IOLs),and determine that which IOL is better for iris-fixation.Methods:15New Zealand white rabbits were randomly divided into three groups:A, B, C (n=5). The operation was performed in the right eyes. Hydrophobic acrylic IOL, polymethylmethacrylate(PMMA) IOL and silicone IOL were respectively implanted in group A,B,and C.The degree of all the IOLs was+20.0D, and all the eyes were cured by iris-fixation. The IOLs were explanted3months later. Opacification of the optic was observed with operating microscope. Light transmittance from300nm to800nm of the optic was measured with a U-3900UV/Vis spectrophotometer (single-beam configuration with integrating sphere).Examinations were performed at room temperature in the balanced salt solution. Results of light transmittance in the visible light spectrum (700to400nm) were analysed.Results:Opacification appeared in all the three types of IOLs. The mean light transmittance in the visible light spectrum was96.78%±0.34%for hydrophobic acrylic IOL;98.46%±0.22%for PMMA IOL;96.79%±0.24%for silicone IOL. There were significant differences in light transmittance between hydrophobic acrylic IOL and PMMA IOL with statistical meanings (t=4.22, P<0.01);there was no statistical difference in light transmittance between hydrophobic acrylic IOL and silicone IOL (t=0.11,P=0.58);the difference in light transmittance between PMMA IOL and silicone IOL was statistically significant (t=4.33, P<0.01). There was no significant difference in light transmittance decline among the3groups.Conclusions:Both opacification and decreased light transmittance appeared in all the three kinds of IOLs in eyes. In order to achieve the best therapeutic effect, we need to make a comprehensive analysis to choose the appropriate intraocular lens.