Nagasaki University, Nagasaki, Japan Comparison between sutureless and sutured scleral fixation intraocular lenses. Yasser Helmy Mohamed, MD, PhD, Azusa Fujikawa, MD, PhD, Takashi Kitaoka, MD, PhD. Department of Ophthalmology and Visual Sciences, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan

The authors have no funding or competing conflicts of interest to report.

Introduction: The advent of foldable intraocular lenses (IOLs) has increased the success rate and early visual rehabilitation after cataract surgery. However, certain perioperative conditions and situations may preclude IOL implantation in the native capsular bag. When endocapsular IOL placement is not possible, the choices include sutured scleral-fixated IOLs, sutureless scleral fixated IOLs, iris-fixated IOLs, iris-claw IOLs, or anterior chamber (AC) IOLs.

Sutured scleral fixation technique: As described by Szurman et al., (2010) Z suture which is a knotless technique for trans-scleral suture fixation of IOLs was used in sutured cases of this study.

Sutureless (Scleral tunnel) technique: As described by Gabor and Pavlidis (2007), 2 straight ab externo sclerotomies were prepared with a sharp 24 gauge MVR 1.5 mm to 2.0 mm from the limbus exactly 180 degrees to each other. This blade was used to create a limbus parallel tunnel of approximately 50% scleral thickness starting from the ciliary sulcus sclerotomies and ending with externalization of the blade after 2.0 to 3.0 mm.

Aim of the study: To compare the outcomes between sutureless (Scleral tunnel ) and sutured (knotless technique) scleral fixation of posterior chamber IOL and also comparing both with usual endocapsular IOL implantation.

Materials and methods: This study is a retrospective comparative study from February to November 2014 in Nagasaki University Hospital for consecutive case series. Sixty two cases (62 eyes) included in this study distributed as follow: 18 eyes had suturless scleral fixation (Scleral tunnel), 18 eyes had sutured scleral fixation (knotless technique), and 26 eyes had usual endocapsular IOL.

Patient files were recruited from the operating room register or medical records department of Ophthalmology, Nagasaki University Hospital. Eyes that had foldable posterior chamber scleral fixating IOL procedures for IOL dislocation, intraoperative posterior capsule rupture, aphakia, or subluxated cataractous lens were included.

Exclusion criteria: included preoperative glaucoma, aniridia, macular scar, traumatic subluxation, dislocated nucleus that required pars plana vitrectomy, incomplete operative medical records, and postoperative follow-up of less than 3 months. Eyes with combined surgical procedures combined with foldable scleral fixating IOL implantation (eg, keratoplasty) were also excluded.

All patients had a standard ophthalmologic examination including: *measurements of best corrected visual acuity (BCVA) *slit lamp examination *measurement of the intraocular pressure *dilated slit lamp biomicroscopy at all pre- and postoperative visits. *The corneal endothelial cell density was measured by specular microscope preoperatively and 3 months postoperatively.

The decimal BCVA was converted to the logarithm of the minimum angle of resolution (logMAR) for the statistical analyses. Evaluation of postoperative outcome of the three groups especially as regards visual acuity improvement, postoperative IOL astigmatism (the difference between the total astigmatism and corneal astigmatism), corneal endothelial cell density, and other complications were determined.

Results: Sixty eyes of 60 patients fulfilled the inclusion and exclusion criteria and two eyes were excluded from the study. One eye related to sutured group and the other related to scleral tunnel group.

Characteristics Sutured IOL Sutureless IOL Endocapsular IOL *Number of Eyes (patients) *Age (range) *Sex (male/female) *Diagnosis Dislocated PC IOL Aphakia Weak zonules *Baseline LogMAR BCVA (mean &SD) *3 months post-operative LogMAR BCVA (mean) *Post-operative IOL astigmatism (mean &SD) *Post-operative endothelial reduction 17 (17) 64.53 (35-82) 17/0   13 2 0.68 0.35 0.71±0.17 7.07% 72 (52-82) 12/5 9 6 0.69 0.31 1.13±0.24 6.72% 26 (26) 71.12 (21-89) - 0.73 0.34 0.60±0.11 5.97%

IOL astigmatism:

Endothelial cell reduction rate%

There were no statistically significant differences between all groups as regards BCVA, average postoperative intraocular lens astigmatism, and the mean corneal endothelial reduction rate after three months of follow up.

Post-operative complications: No serious complications, namely, retinal detachment, endophthalmitis, IOL dislocation, or vitreous hemorrhage, were detected during the follow-up period in the three groups.

Discussion: Trans-scleral IOL fixation has several potential risks such as endophthalmitis due to erosion of the sutures through the conjunctiva, IOL dislocation due to suture degradation, vitreous hemorrhage, and IOL tilt associated with inaccurate placement of the fixation sutures. Gabor and Pavlidis (2007) described a technique for intrascleral fixation of both haptics in the ciliary sulcus using a parallel scleral tunnel.

The biggest advantage of using intrascleral fixation is that stronger fixation of the IOL is achieved because the haptic sits in a scleral tunnel, which reduces the possibility of IOL decentration or tilt. Anatomical stability of the IOL leads to optical stability and better postoperative refraction. Another advantage of intrascleral fixation is that IOL decentration after surgery can be easily corrected. In contrast, postoperative repositioning of the IOL is difficult after suture fixation.

Sutureless technique also simplifies the scleral fixation of a dislocated PC IOL and allows successful repositioning of dislocated and subluxated PC IOLs. Moreover, a small incision is adequate for surgery, the learning curve is short, and the operating time can be reduced. Sutureless scleral fixation is theoretically compatible with multiple different IOL types and does not require specialized haptics containing suture eyelets.

Limitations of the study: However, bigger number of patients and longer follow-up is needed to determine the potential for late IOL dislocation and other late complications, such as scleral degeneration and haptic position in the sclera.

Conclusion: In this study, we evaluated our experience with two techniques of scleral fixation. Both techniques demonstrated statistically significant improvement in visual acuity and a low incidence of short term complications. We have achieved excellent IOL centration and avoided any dislocations in our cohort. No additional surgery has been required.