Short-term Dynamics after Single- and Three-piece Acrylic Intraocular Lens Implantation: A Swept-source Anterior Segment Optical Coherence Tomography Study

Abstract

Accurate alignment of an intraocular lens (IOL) is indispensable for achieving accurate postoperative refractive outcomes. Thus, we evaluated decentration and tilt of single- and three-piece IOLs, as well as anterior chamber depth (ACD), at 3 hours, 24 hours, 2 weeks, and 4 weeks after cataract surgery, using swept-source anterior segment optical coherence tomography. There was no significant difference in postoperative visual acuity between eyes with single- or three-piece IOLs. Absolute values of IOL decentration at 24 hours and 2 weeks after surgery were significantly larger (P = 0.008 and 0.046, respectively) in eyes with the single-piece IOL than in those with the three-piece IOL. Both single- and three-piece IOLs tended to tilt toward the inferotemporal direction; however, there was no significant difference in the absolute values of IOL tilt at any postoperative time point. ACD at 24 hours after surgery was significantly deeper (P = 0.009) in eyes with the three-piece IOL, compared with eyes with the single-piece IOL. Therefore, although both single- and three-piece IOL locations varied transiently after surgery, IOL locations were similar between both IOLs at 4 weeks after surgery and were not associated with any statistical difference in visual function.

Effect of Intraocular Lens Tilt and Decentration on Visual Acuity, Dysphotopsia and Wavefront Aberrations

“…Kemer et al [ 38 ] reported the mean IOL tilt angle of 3.80° ± 4.09° in the horizontal axis and 2.83° ± 4.03° in the vertical axis in 94 eyes with Z-sutured scleral fixated using AS-OCT without pupil dilation. Barca et al [ 39 ] reported mean tilt of 2.08° ± 1.19° in 32 eyes with a sutureless single piece scleral fixated IOL following pupil dilation and Ibrahim et al [ 40 ] reported lens decentration range between 0.21 mm and 0.9 mm and IOL tilt ranged between 1.2° and 2.8° in 6 patients with suture fixated sulcus IOLs using AS-OCT. CASIA2 (Tomey Corp., Nagoya, Japan) is a second-generation Swept source AS-OCT with scan depth of 13 mm [ 5 ]. It is an efficient method to measure IOL tilt and decentration with high repeatability.…”

“…In fact compared to the pupil centre, corneal vertex is considered to be a better reference to assess tilt and decentration because it is not affected by pupil shape [ 11 ]. Sato et al [ 5 ] assessed tilt and decentration in short-term postoperative period using CASIA2 (Tomey Corp., Nagoya, Japan) and found very high inter-observer and intra-observer reproducibility.…”

“…For instance, pupillary axis has been used as the reference axis by several studies in the past [ 2 , 3 ]. However, corneal vertex [ 4 ] and visual axis [ 5 ] were employed by newer devices and studies to measure the IOL tilt and decentration.…”

“…Some studies have evaluated and compared preoperative crystalline lens tilt and decentration with postoperative IOL displacement. On average a 5° inferotemporal tilt was noticed in both crystalline lenses and IOLs, [ 4 , 5 , 6 , 7 ] indicating that the fovea was slightly temporal to the pupillary axis of the eye [ 6 ]. Furthermore, significant correlations were found between pre- and postoperative data for both tilt and decentration [ 6 , 7 ].…”

Effects of capsular tension ring on surgical outcomes of premium intraocular lens in patients with suspected zonular weakness

“…The degree of IOL decentration and tilt was measured using swept-source anterior segment optical coherence tomography (AS-OCT, CASIA2, Tomey Corp., Nagoya, Japan) [12,13]. This instrument performs a three-dimensional analysis with 16 different angles of AS-OCT images, then automatically measures the amount of IOL decentration and tilt relative to the visual axis.…”