Aim To determine the higher-order aberrations of intraocular lenses (IOLs) that are extended and fixed intrasclerally.
Methods A computer-aided design system was used to calculate the length of an IOL when it was fixed to the sclera 2 mm posterior to the limbus in a Gullstrand eye model. An acrylic single-piece (SA60AT) or 2 three-piece IOLs (VA-60BBR; X-60) were fixed at lengths of 13, 14, 15 and 16 mm. A wavefront analyser was used to measure the higher-order aberrations within the central 3.0 and 5.2 mm optic diameters.
Results The length of the IOL with the intrascleral fixation was calculated to be 13.9–14.9 mm in the eye model. The astigmatic aberration of the three-piece VA-60BBR and X-60 IOLs increased significantly with an extension of the IOLs within the central 5.2 mm (both p<0.001) but not that of the single-piece SA60AT IOL. The coma aberration of the VA-60BBR IOL increased significantly within the central 5.2 mm with an increase in the extension (p=0.001) but not that of the SA60AT and X-60 IOLs. The astigmatic and coma aberrations were significantly greater within the central 5.2 mm than within the central 3.0 mm for all IOLs (p<0.05). The cylindrical power increased from 0.034 D to 0.082 D with extensions from 13 to 16 mm.
Conclusions When three-piece IOLs are extended widely for intrascleral fixation, the astigmatic and coma aberrations increase but the degree of change should not alter the postoperative vision appreciably.
- Treatment Surgery