Intrascleral Fixation of an Intraocular Lens through the Pars Plana Prevents Corneal Endothelial Damage

Intrascleral intraocular lens (IOL) fixation is a standard technique for secondary implantation of IOLs in eyes without or with insufficient capsular support. Numerous variations of this technique have been reported [1-8]. Most procedures create a corneoscleral or corneal incision and require the placement of an IOL on the iris following some intracameral manipulations. Therefore, intrascleral IOL fixation must be performed with utmost care to prevent further damage to the diminished corneal endothelial cells. Corneal endothelial transplantation has recently been developed [9, 10]; however, if possible, secondary IOL implantation procedures should be avoided requiring corneal transplantation. Therefore, we proposed that corneal endothelial cells could be preserved by performing all intraocular manipulations posterior to the iris through a scleral incision at the pars plana, thereby avoiding the cornea. Here, we report the successful preservation of corneal endothelial cells using this method in two cases.

Intrascleral fixation of the IOL in each case was performed using our previously reported modified lock-and-lead technique [7, 8]. Briefly, an infusion trocar cannula was placed through the pars plana 3.5 mm from the limbus. The anterior vitreous was thoroughly removed. Under perfusion, a sclerotomy was made 2.5 mm from the limbus at the 5 o’clock position using a 20-G microvitreoretinal knife (Fig. 1A). Using a slit knife, a 3-mm scleral incision was made parallel to and 2.5 mm from the limbus opposite to the first sclerotomy site (Fig. 1B).

After the IOL was loaded into the injector, the catheter needle was inserted through the sclerotomy and penetrated through the 3-mm scleral incision (Fig. 1C). A modified guidance needle, which mimics a catheter needle, is used to fix IOL haptics between the external tube and the internal needle. The plunger of the injector was advanced until the leading haptic was released. The leading haptic was fixated between the external tube and the internal needle of the catheter needle outside of the scleral incision. Simultaneously, the catheter needle was pulled until the leading haptic exited the sclerotomy site, and the IOL was inserted into the eye through the 3-mm scleral incision (Fig. 1D). The catheter needle was loosened to release the leading haptic external to the sclerotomy site, while the trailing haptic remained external to the 3-mm scleral incision (Fig. 1E). Two 30-G ultrathin needles were prepared and used to bury the leading haptic in the scleral tunnel (Fig. 1F). The trailing haptic was buried in the scleral tunnel through the edge of the 3-mm scleral incision using two 30-G needles (Fig. 1G). The IOL centering and alignment were adjusted into position, and the scleral incision was closed using 8-0 nylon suture (Fig. 1H). The perfusion was stopped, and the conjunctival wound was sutured using 8-0 Vicryl. A summarization of the procedure is shown in online supplementary video 1 (for all online suppl. material, see www.karger.com/doi/10.1159/000496534).

We performed this surgical procedure in two cases. A summary of the patients is shown in Table 1. Postoperative slit-lamp photographs and anterior segment optical coherence tomography are shown in Figure 2. No complications were observed during surgery or in the early postoperative phase. In both cases, we successfully preserved the corneal endothelial cells. However, the postoperative best corrected visual acuity was decreased in one case, partly due to superficial keratoconjunctivitis and mild dementia.

In these two cases, we successfully performed intrascleral fixation of an IOL while preserving the corneal endothelial cells. Eom et al. [11] compared combined phacovitrectomy to pars plana vitrectomy with fragmentation and found that the latter method resulted in less endothelial damage. It is logical that procedural manipulations should be performed distant to the endothelial cells to prevent endothelial damage.

A 3-mm scleral incision was needed to insert the IOL through the pars plana. This is unusual; however, it is often required for the removal of intraocular foreign bodies. Although the incision is uncommon, our method has several advantages. Insertion of the trailing haptic into the scleral tunnel is facilitated by the highly flexible, 3-mm scleral incision. Therefore, we could easily determine the direction of the scleral tunnel and align the IOL. Less postoperative intraocular hemorrhage occurs from the pars plana than from the ciliary groove, the usual site for IOL scleral fixation. Since the IOL is positioned away from the iris plane, postoperative iris capture is avoided. Serious complications, such as postoperative hypotony, retinal detachment, and haptic scleral erosions, were not observed in either case.

We used to use the same IOL power for this procedure as that employed for an in-the-bag fixation through a sclerotomy 1.5 mm from the limbus. In the cases reported here, we selected an IOL with a refractive power 1 dpt higher than that used in our previous procedures, because the IOL was fixed 2.5 mm from the limbus, posterior to our standard method. The postoperative refraction was as expected.

This report includes only two cases and is limited in scope. Therefore, further studies in additional patients are required to determine the effects of this technique on lens power selection. However, we believe this technique minimizes corneal endothelial cell damage during IOL intrascleral fixation in select cases.

The authors have no ethical conflicts to disclose.

Dr. Masayuki Akimoto is a consultant for Kowa Co., Ltd., Nagoya, Japan. The other authors have no financial support to disclose.

N.M. and M.Y. interpreted data. N.M. and M.A. wrote the paper. M.A. performed surgery and supervised it.

Presented at the 41st Annual Meeting of the Japanese Society of Ophthalmic Surgeons, Kyoto, Japan, January 2018.