The ideal placement of an IOL is within the capsular bag, the anatomical position. However, in eyes with inadequate capsular support, the intrascleral posterior chamber IOL fixation technique is advantageous over other IOL implantation techniques because of its stability and proximity to the physiological anatomical position of the original lens.[1-3, 10] The most common indications for this procedure include posttraumatic aphakia, aphakia after complex cataract surgery, or lensectomy during complex surgical procedures, such as RD repair, PDR, IOL dislocation, or crystalline lens subluxation.
The various intrascleral IOL fixation techniques can be broadly classified as either sutured or sutureless. Sutureless techniques for scleral IOL fixation have advantages because they do lead to suture degradation, late IOL dislocation caused by broken sutures or other suture-related complications. The critical difference between these techniques is the manner in which the haptics of the IOL are handled. Gabor and Agarwal et al. achieved sutureless scleral IOL fixation using fibrin glue to close the scleral flaps.[14, 15] Ohta et al. created a Y-shaped scleral incision to fix the haptic without using fibrin sealant.[3, 18] Yamane et al. developed a double-needle technique and flanged IOL fixation technique to provide firm haptic fixation without using suture or glue.[1, 2]
There are two surgically challenging steps in intrascleral-fixated IOL procedures. The first is externalization of IOL haptics. The intraocular forceps technique was reported by Gabor and Pavlidis, but this technique might cause deformation of the IOL haptics. The double-needle technique, which was reported by Yamane, might make it difficult to grasp the second haptic and insert it into a scleral tunnel after the first haptic is externalized.[1, 2] Therefore, compared with other techniques, our approach solves the problem of the difficulty in grasping the second haptic after externalization of the first haptic. Meanwhile, it can minimize the risk of multiple anterior segment manipulations. It is a simple and reliable surgical technique that is suitable for beginners and surgeons with limited experience. Each step of this technique is simple, and it is easy to perform with a short learning curve. In our procedure, a disposable 27-gauge syringe needle is used to create the sclerotomy, and a lead 8-0 suture is inserted into the posterior chamber to guide haptic externalization. During externalization, there is no risk of the IOL falling into the vitreous cavity because the sutures were used to tie knots at the end of each haptics. Since large diameters sclerotomy can result in wound leakage and postoperative hypotony, we used 27-gauge needles, which caused minimal damage to the conjunctiva and sclera and created a self-sealing sclerotomy wound. No other intraocular surgical instruments or manipulations were required at this step, which minimized possible damage to the cornea, peripheral retina, and other intraocular tissues. Fewer anterior segment manipulations may result in faster postoperative visual rehabilitation and a lower risk of anterior segment complications, such as corneal decompensation.[24, 25]
The second surgically challenging step in this procedure is fixation of each IOL haptic inside the scleral tunnel. Intrascleral IOL fixation techniques could also be classified into those with and without a scleral flap.[2, 3] Techniques without a scleral flap are simpler and do not require sutures or fibrin glue. However, there is a potential risk of haptic extrusion. Unstable intrascleral fixation may cause IOL decentration or dislocation, which may impact refraction and visual function.[26, 27] IOL haptic fixation is easily accomplished using techniques with a scleral flap, but the surgical procedure is relatively complex. However, the possibility of the haptics extrusion and the IOL slipping into the vitreous cavity by simply using flanged end fixation can be well prevented by the scleral flap.[19, 28] Making appropriately flanged ends is a critical process in our approach. During our procedure, we flanged the haptic ends prior to placement into the anterior chamber. The main purpose of the first flange is to allow the 8-0 sutures to anchor. We learned that satisfactory suture fixation can be achieved by making the first flanged end approximately 1.2 times larger than the bare haptics and that externalization of the haptics is less affected by flanged ends of this size. The diameter of the haptics of the 3-piece IOL is 0.14 to 0.17 mm, the outer diameter of the 27 gauge needle is 0.42 mm, and the diameter of the 8-0 absorbable sutures is less than 0.01 mm.[1, 3, 29] It is larger enough for the needle-created incision to retrieve the haptics after the 1.2 times larger flange creation and “several knots” of the sutures tied. There is resistance when the flanged end passes through the sclerotomy, especially at the moment of scleral breakthrough. As a result, we made scleral flaps, about one-half to two-thirds thickness, to decrease friction. Therefore, the tension of the sutures is sufficient to guide the IOL haptics through the scleral tunnel without the suture breaking or the knot slipping. In the final stage of the surgery, a sufficient flange, approximately 1.5 times larger than the bare haptics, was created at the end of each haptic using an ophthalmic cautery device. Then, each flange of the haptics was pushed back and fixed into previous needle-created scleral tunnel. The size of the flange is sufficient to prevent the haptic slipping through the tunnel because of the elasticity of the scleral tissue. Moreover, the haptics were buried under 3.0 mm scleral flaps, which minimizes the risk of haptic extrusion or dislocation, and prevents the IOL from falling into the vitreous cavity. This technique achieved a secure and stable fixation of the haptic in the intrascleral tunnel.
According to Sindal, eyes with posttraumatic aphakia have better visual outcomes after scleral-fixated IOL implantation. Although there can be long-term suture-related complications from IOL implantation, including suture degradation or breakage associated with IOL decentration or dislocation, no differences in the outcomes or complication rates were observed between sutured and sutureless sclera-fixated IOL implantation techniques. Considering the scleral flaps that we made previously, we believed that closure with sutures was needed in our procedure. The main purpose of the suturing is to close the scleral flaps, which can be replaced by the use of fibrin glue. However, there is little possibility of suture erosion-related IOL decentration because the haptics of IOL were fixated by flanged end rather than sutures. UBM and anterior segment OCT demonstrated a securely fixated IOL and well-centered optic (Figure 3).
Both primary and secondary intrascleral-fixated IOL implantation are associated with favorable visual outcomes. However, we prefer to perform IOL placement after the primary surgery to address the coexistent clinical condition. Lee et al. found that eyes undergoing primary IOL implantation may have a greater risk of postoperative inflammation with associated complications like CME.[12, 30] Compared with primary scleral-fixated IOL placement, secondary IOL implantation seems to have a lower early complication rate in complicated cataract extraction, although the final visual acuity and late complication rate are not significantly different.
All 14 patients underwent primary vitrectomy surgery, lensectomy with or without silicone oil tamponade for the treatment of a coexisting clinical condition (e.g. ocular trauma, RD, PDR, or lens dislocation). Primary three-port PPV was performed because all of our patients required complicated retinal surgery. When complicated with cataracts, these ocular diseases are the major causes of severe visual impairment. For eyes lacking sufficient capsular support, we recommended anterior vitrectomy or PPV before IOL fixation. Vitreous incarceration and traction caused by the sutures or the IOL haptics can be prevented by vitrectomy surgery. Meanwhile, a complete vitrectomy with shaving of the vitreous base can release vitreoretinal traction to avoid postoperative retinal tear or detachment.[12, 31]
Although our patients had coexistent ocular conditions, the postoperative BCVA was significantly different from the preoperative BCVA (P=0.011). However, the BCVA did not improve in 4 cases during the follow-up period. Two patients had severe PDR with poor glycemic control, one patient had long-standing RD before the primary operation, and the other patient suffered from a complicated ocular trauma. We believe these patients had severe visual impairment and unsatisfactory visual outcomes because of their complicated ocular and systemic diseases.
Tilt and decentration are also important predictors of accurate IOL positioning. According to Holladay, spherical aberration resulting from abnormal IOL positioning was sufficient to decrease the visual acuity when the tilt was more than 7° and the decentration was more than 400 μm.[7, 32] The mean tilt (2.27 ± 1.12°) and decentration (295 ± 125 μm) in our study are similar to those in other studies, suggesting that the impact on the optic system is acceptable.[1, 2, 6, 7, 33] The rate of mean endothelial cell loss was 7% ± 6%. Multiple mechanisms may be involved in corneal endothelial cell loss, such as surgical injury, systemic diseases, and intraocular perfusion during surgery. Since the endothelial cell counts begins to stabilize approximately 1 year after surgery, a longer follow-up observation period is required. 
According to a large retrospective study by Todorich, the most common complications after intrascleral-fixated IOL surgery were VH and CME. The major postoperative complications of our procedure were postoperative hypotony (3 of 14 cases) and transient ocular hypertension (2 of 14 cases), which returned to the normal intraocular pressure range within one month without further complications. Postoperative hypotony has been reported as a common complication of the intrascleral IOL fixation technique. Larger corneoscleral incision and sclerotomy incisions may carry the potential risk of transient postoperative wound leakage.[1, 6] In our cases, hypotony resolved spontaneously without any intervention. Postoperative ocular hypertension could be explained by mild viscoelastic material retention and steroid response. Transiently IOP elevations were controlled by antiglaucoma medications without affecting the final visual outcome. Since vitrectomy surgery has been previously performed in all cases, no cases of VH or CME were detected during the follow-up period.
There are limitations to our study, including the small sample size, limited follow-up period, and lack of a control group. A longer follow-up period is needed to further assess corneal endothelial loss, long-term IOL stability and postoperative complications. In these 14 cases, there was no evidence of IOL decentration or dislocation, no severe complications, and no cases of haptic erosion during the follow-up period.
In conclusion, our 27-gauge needle-guided intrascleral IOL fixation technique with 8-0 absorbable sutures might be useful for IOL implantation in eyes without sufficient capsular support. This technique is easy to perform, and achieves both anatomical and optical stability, which has fewer potential risks of IOL decentration and dislocation. However, a longer follow-up observation period is required to examine the long-term anatomical and functional outcomes associated with this technique.