Sutureless Intrascleral Intraocular Lens Fixation Using a Microtube-Assisted Technique

Abstract

Anterior chamber intraocular lens (IOL), iris-fixed IOL, and transscleral posterior chamber IOL suture fixation have been used to treat eyes without sufficient capsular support. Recently, intrascleral IOL fixation, in which IOL haptics are pulled out transsclerally and fixed to the sclera, has been widely performed due to good visual outcomes or as a convenient means of sutureless haptics fixation. Several techniques have been reported to externalize IOL haptics.1,2 Of these, forceps or needles are commonly used for externalization of the IOL haptic because of the straightforward nature of the procedure.3–5 However, both techniques have several limitations. Extracting the IOL haptics with forceps is relatively easy but has the potential to damage the IOL haptics or ciliary body. The needle-guided technique may reduce the risk of the ciliary damage but requires sufficient skill to guide the IOL haptics into the needle in the anterior chamber. Especially in insufficient mydriasis cases, guiding the IOL haptics into the needle is difficult, even for experienced surgeons. Furthermore, both techniques require an intraocular procedure, with the possibility of corneal endothelial cell loss. Here, we report a novel technique for externalizing IOL haptics with a microtube. This technique eliminates the need for an intraocular procedure and, therefore, may minimize perioperative complications. Methods Subjects This was a prospective interventional case series. The experimental protocol was approved by the ethics review boards of our institutions, and the protocol adhered to the tenets of the Declaration of Helsinki. Written informed consent was obtained from all patients after an explanation of the nature and possible consequences of the study. Patients with aphakia, a dislocated IOL, or a subluxated crystalline lens were included in this study. Standard eye examinations, including best-corrected visual acuity (BCVA), slit-lamp evaluation, intraocular pressure measurements, and corneal endothelial cell density measurements, were performed before and after the operation; medical records provided additional data. Each BCVA was recorded as the decimal visual acuity and converted to Snellen visual acuity ratios and the logarithm of the minimal angle of resolution (logMAR). Intraocular lens astigmatism was calculated by drawing corneal astigmatism from total astigmatism as reported previously.3 Surgery The surgeries were performed by a single surgeon (K.Y.) at the Department of Ophthalmology, Yokohama Minamikyosai Hospital. Under retrobulbar anesthesia, all patients underwent transconjunctival 25-gauge (G) pars plana vitrectomy using a trocar cannula system with a closure valve (Constellation; Alcon, Fort Worth, TX) to remove the residual vitreous body. A noncontact wide-angle viewing system (Resight 500; Carl Zeiss Meditec, Jena, Germany) was used for intraoperative observation of the eye's interior. Phacoemulsification cataract surgery was performed for the case with a subluxated crystalline lens. In the cases with a dislocated IOL, IOLs were extracted through 6.0-mm scleral incision. For IOL haptics externalization, a needle with a silicon microtube was used (Figure 1) (see Video 1, Supplemental Digital Content 1, https://links.lww.com/IAE/A933). The length of the needle was 18 mm. The inner and outer diameters of the microtube were 0.2 and 0.3 mm, respectively. This instrument is still being tested and is not commercially available.Fig. 1.: Needle with microtube. The length of the needle is 18 mm. The inner and outer diameters of the microtube are 0.2 and 0.3 mm, respectively.The needle with microtube was transconjunctivally passed through the sclera from the 8 o'clock position to 10 o'clock, 1.75 mm from the limbus to create a scleral tunnel (Figure 2A). The needle with microtube was inserted into the sulcus space from the site that the needle was pulled out at the 10 o'clock position (Figure 2B). A transconjunctival approach was used to insert a 27-G needle into the sulcus space at the 4 o'clock side, 1.75 mm from the limbus, and the needle containing the microtube was inserted into the lumen of the 27-G needle (Figure 2C). The 27-G needle was pulled out with the needle with microtube at the 4 o'clock side (Figure 2D). The needle with microtube was transconjunctivally inserted into the sclera from the site that the needle with microtube was pulled out at the 4 o'clock side and passed through the sclera from 4 o'clock to 2 o'clock to create a scleral tunnel (Figure 2, E and F). Both ends of the microtube were pulled as the redundant looped microtube was being drawn under the scleral tunnel and resolved (Figure 2G). During the procedure, the microtube passed through the sulcus space from 10 o'clock to 4 o'clock and passed through the sclera from 2 o'clock to 4 o'clock and from 8 o'clock to 10 o'clock. Then, the center of the microtube was pulled out through the incision made for injecting the IOL and cut by microscissors (Figure 3, A and B). A three-piece IOL (NX-70; Santen, Osaka, Japan) was loaded into an injector, and the plunger was pushed slightly until the leading haptic appeared outside the injector. After the leading haptic was loaded into the microtube and passed through the 4 o'clock sclera outside the anterior chamber, so that half of the haptic was covered by the microtube, the IOL was inserted into the anterior chamber (Figure 3, C and D). The trailing haptic was loaded into the microtube passed through the 10 o'clock sclera and inserted into the anterior chamber (Figure 3, E and F). The microtube was pulled out, so that the haptics were externalized (Figure 3G). The tips of the haptics were cauterized to make flanges with an ophthalmic cautery device (Accu-Temp Cautery; Beaver Visitec, Waltham, MA) and then pushed back into the sclera for fixation (Figure 3, H and I).Fig. 2.: Microtube insertion into the sulcus space. A. A needle with microtube was transconjunctivally passed through the sclera from 8 to 10 o'clock, 1.75 mm from the limbus to create a scleral tunnel. B. The needle with microtube was inserted into the sulcus space from the site that the needle was pulled out at the 10 o'clock position. C. A transconjunctival approach was used to insert a 27-G needle into the sulcus space at the 4 o'clock side, 1.75 mm from the limbus, and the needle with microtube was inserted into the lumen of the 27-G needle. D. The 27-G needle was pulled out with the needle with the microtube at the 4 o'clock side. E. The needle with microtube was transconjunctivally inserted into the sclera from the site that the needle with microtube was pulled out from. F. The needle with microtube was passed through the sclera from 4 to 2 o'clock to create a scleral tunnel. G. Both ends of the microtube were pulled, so that the redundant looped microtube could be drawn under the scleral tunnel and resolved.Fig. 3.: Externalizing the IOL haptics with the microtube. A. The microtube was pulled out by a lens hook through a corneal incision. B. The microtube was cut by microscissors. C. The leading haptic was loaded into the microtube and passed through the 4 o'clock sclera site. D. The IOL was inserted into the anterior chamber. E. The trailing haptic was loaded into the microtube and passed though the 10 o'clock sclera. F. The trailing haptic was inserted into the anterior chamber. G. The microtube was pulled out, so that the haptic was externalized. H. The tips of the haptic were cauterized to make flanges. I. The haptics were pushed back into the sclera.Results This study included four eyes of five patients (mean age, 71.2 ± 10.8 years). Two patients were men (mean age, 68 ± 14.1 years), and three were women (mean age, 73.3 ± 10.7 years). Two cases were of aphakia, two were of dislocated IOL, and one case was of a subluxated crystallin lens. The patients' clinical characteristics are listed in Table 1.Table 1.: Patient CharacteristicsThe preoperative mean BCVA was 6/12 (0.29 logMAR), and the mean postoperative BCVA was 6/7 (0.05 logMAR) at 1 month. The mean preoperative corneal endothelial cell density was 2,357 cells/mm2, and the postoperative corneal endothelial cell density was 2,181 cells/mm2 at 1 month. The mean IOL astigmatism was 0.50 ± 0.17 D. Although postoperative hypotony was observed in one case, the IOP was normalized within 1 week postoperatively. Other complications such as vitreous hemorrhage, iris capture by the IOL, rhegmatogenous retinal detachment, and choroidal detachment were not observed. In all cases, the haptics were well-fixed, and the IOL was centrally positioned. Discussion Externalizing the IOL haptics is imperative for intrascleral IOL fixation. However, previously reported techniques required a challenging intraocular maneuver to capture the haptics; these procedures were associated with various complications that included IOL haptics deterioration, iris damage, corneal endothelial damage, vitreous hemorrhage, and rhegmatogenous retinal detachment. In the current study, we demonstrated a novel technique to externalize the IOL haptic using a microtube. This technique eliminates the need for an intraocular procedure because the leading haptic is loaded into the microtube outside the anterior chamber and externalized by pulling out the microtube. We transconjunctivally performed intrascleral IOL fixation, reducing the laborious procedure associated with incising the conjunctiva and making a scleral flap. Especially in cases with unintentional capsular removal during cataract surgery and IOL implantation, the transconjunctival technique could be of great assistance for surgeons. The microtube-assisted technique can also be used after incising the conjunctiva and passing through the sclera or making a scleral flap. As incising the conjunctiva would make it easier to pass precisely through the sclera, it could be an option for patients who would not subsequently undergo ophthalmic surgeries such as for glaucoma. Making a scleral flap is also an option for the microtube-assisted technique, especially for surgeons who are accustomed to transscleral IOL suture fixation. Our technique would be helpful for these surgeons, as the procedure of inserting a microtube is similar to ab externo IOL suture fixation. We used a microtube with an inner diameter of 0.2 mm. We also attempted to use 2 other microtubes with inner diameters of 0.1 mm and 0.3 mm. The 0.1-mm inner diameter microtube was too thin to insert the IOL haptics because the diameter of the haptics of commonly used 3-piece IOLs is 0.14 to 0.17 mm. The 0.3-mm inner diameter of the microtube made it easy to insert the IOL haptics, but IOL haptics had a tendency to slip inside the microtube. The 0.2-mm inner diameter of the microtube was the most suitable size because it was easy to insert the IOL haptics into the lumen of the microtube, with minimal slippage. Among previous studies using the needle-guided technique, a 27-G needle or 30-G thin-walled needle was commonly used. The inner diameter of the 27-G needle was 0.22 mm, and that of the 30-G thin-walled needle was 0.2 mm, which was almost the same size as the inner diameter of the microtube that we used.4,5 Among all cases, we experience no IOL haptics dislodgment from the microtube. However, there is a possibility of such dislodgement if excessive forces are exerted on the microtubes or IOLs. The needle-guided technique also carries this risk. Therefore, careful procedures inside the ocular space are required. In conclusion, we described a novel procedure of intrascleral IOL fixation using a microtube. This procedure is easy to perform due to elimination of steps requiring intraocular haptic manipulation. Additional studies with a larger number of patients and various types of IOLs are required to confirm the effectiveness of our technique.