Pars plana vitrectomy in management of giant retinal tear and retinal detachment following iris-fixated anterior chamber phakic intraocular lens implantation

Abstract

This case report describes a 26-year-old man presenting with a giant retinal tear (GRT) with retinal detachment (RD) following implantation of iris-fixated anterior chamber phakic intraocular lens (AC-PIOL) for high myopia and occurrence of intraoperative aberrations during vitrectomy due to the presence of AC-PIOL in situ. Posterior chamber PIOL have been well reported to be associated with GRT with RD. Very few reports exist of GRT with RD following AC-PIOL. Moreover, the presence of iris-fixated AC-PIOL, in this case, led to the formation of ghost images intraoperatively especially during crucial steps like induction of posterior vitreous detachment which has never been reported.

Background

Phakic intraocular lens (PIOL) implantation is a frequently performed refractive procedure offering correction for a higher degree of myopia compared with corneal refractive procedures.^{1 2} Various mechanisms have been postulated for the occurrence of retinal detachment (RD) following posterior chamber (PC) and anterior chamber (AC) PIOL implantation.^{1 3 4} Limited literature exist regarding the occurrence of a giant retinal tear (GRT) following AC-PIOL.

Case presentation

A high myopic male patient of age 26 years presented to us with diminution of vision in the left eye (OS). He had undergone both eyes (OU) iris-fixated phakic IOL (Artisan(R), Ophtec, Groningen, The Netherlands) implantation for myopia of −13D right eye (OD) and −11D OS 3 months back (figure 1A). Preoperative visual acuity and fundus changes were documented to be within normal limits in the previous hospital records with no evidence of complicated surgery and no peripheral lesions present in either eye. There was no history of ocular trauma or family history of RDs.

Figure 1.

(A) Slit-lamp examination showing iris-fixated type AC-PIOL. (B) Vaulting of IOL on slit-lamp examination. AC-PIOL, anterior chamber phakic intraocular lens.

Investigations

At presentation, best corrected visual acuity (BCVA) was 6/12 OD and counting fingers at 1 metre OS. Intraocular pressures (IOP) were 15 mm Hg OD and 16 mm Hg OS. Slit-lamp examination revealed an adequate vaulting of both the AC-PIOLs (figure 1B) which was confirmed on anterior segment optical coherence tomography (AS-OCT) (figure 2). Axial lengths were measured as 31.8 mm OD and 29.2 mm OS. Fundus examination OS showed the presence of an inferior rhegmatogenous RD with detached macula along with a GRT (6 clock hours) having a mobile posterior flap (figure 3A). Fundus examination OD showed myopic fundus with no peripheral treatable lesion and no posterior vitreous detachment (PVD).

Figure 2.

Anterior segment OCT of left eye revealing a AC-PIOL vaulting of 215 µm. OCT, optical coherence tomography.

Figure 3.

(A) Preoperative Optos^(R) wide-field pseudocolour imaging of left eye showing a GRT with inferior RD. (B) Postoperative Optos^(R) wide-field pseudocolour fundus image of the left eye showing attached retina with silicon-oil in situ. GRT, giant retinal tear; RD, retinal detachment.

Treatment, outcome and follow-up

The patient underwent 23-gauge pars plana vitrectomy along with encirclage and silicone oil injection. The encirclage was put in order to support the vitreous base. Intraoperative perfluorocarbon liquid helped in proper manipulation of the GRT flap. On the postoperative day 4, BCVA was 6/36 OS which further improved to 6/24 at the end of 1 month with retina well attached (figure 3B). Postoperative IOP was 13 mm Hg OS. Intraoperatively, the presence of the AC-PIOL led to formation of ghost images because of aberrations probably arising from the IOL edge during manipulation under Chalam^(R)Self-Stabilising Vitrectomy (SSV) Planoconcave lens (figure 4), during steps like PVD induction, which needed extra care during manipulation of the vitrector. These were however not noted while operating under the wide-field viewing system.

Figure 4.

Intraoperative aberrations noted as ghost images viewed through the Chalam^(R) -SSV lens (planoconcave) due to the presence of AC-PIOL in situ. AC-PIOL, anterior chamber phakic intraocular lens;SSV, Self-Stabilising Vitrectomy.

Discussion

Complications of PIOLs encompass AC complications like cataract, pigment dispersion and glaucoma and PC manifestations like RDs, breaks, macular oedema and so on. Apart from two reports of GRT with RD, literature in this area is lacking in evidence.^{3 4}

Options for high myopia correction available today are clear lens extraction with IOL implantation, PIOL implantation and corneal refractive surgeries.^{1 5 6} After the USFDA approval of PIOLs, with their extended use, rhegmatogenous RD have been reported after both AC-PIOLs and PC-PIOLs.3 4 7 8 The incidence of RD in eyes with AC-PIOL has been estimated at 2.9%–7.1% with a mean interval between AC-PIOL and RD being 24.4±24.4 months.⁷ Moderate and high myopia patients are at a significantly high risk for RD, with eyes of axial length >30.24 mm being especially predisposed.⁷ RD following PC-PIOL insertion with GRT and giant retinal dialysis has been postulated to be developing because of traction to vitreous base ensuing liquefaction.⁹ Although previous reports suggested eyes with precursor lesions be treated before refractive surgery, Panozzo and Parolini demonstrated that breaks after PC-PIOL surgery may also develop in treatment naïve areas.^{3 7 9} Apart from perioperative IOP fluctuations and/or iatrogenic inflammation, inflammation induced by polymethylmethacrylate material of the AC-PIOL has also been proposed as a possible cause behind GRT formation.⁴ Causal association in our case between AC-PIOL and GRT seems plausible from the facts that there is the absence of preoperative predisposing lesions (as per records), the presence of a temporal association (only 3 months between the surgery and GRT) and the absence of a family history of RD. These complicated detachments are treated with vitreoretinal surgery using gas/silicone oil tamponade.

Surgery with an iris-fixated AC-PIOL may be challenging to a vitreoretinal surgeon due to edge effects. In our case, the intraoperative difficulties that we faced during pars plana vitrectomy included problems in visualisation due to aberrations produced at the edge of the optical zone (figure 4). Ghosting is expected to occur in any situation where multiple foci are present; in this case, when light passed both through the optic and beyond the optic periphery through the clear lens (figure 1A). This may be a problem with diffractive multifocal lenses too. The aberrations were especially marked while operating under Chalam^(R) SSV planoconcave lens as compared with the wide-angle viewing system (MiniQuad XL contact wide-angle viewing lens, Volk Optical) probably due to higher magnification, smaller field of view and increased depth of focus. These aberrations lead to difficulties in crucial steps such as induction of PVD. However, by shifting to the wide-field viewing system through which aberrations were seen to be lesser and by being more careful in approaching the peripheral vitreous while viewing through the edge of the IOL, the case was managed.

To summarise, retinal screening should be conducted for every patient before and after refractive surgeries. Patients should be counselled regarding early symptoms of RD. Most of the PIOL surgeries are performed in patients with high myopia who are already at a high risk of RD. The exact relationship between AC-PIOL implantation and RD needs further exploration by well-designed prospective studies with a large number of patients. Since early surgical intervention for RD ensures good anatomical and visual outcomes, it is important to keep in mind the intraoperative aberrations that may arise due to the presence of AC-PIOL in such patients which requires judicious use of wide-angle viewing systems.

Learning points.

• Giant retinal tears may occur after anterior chamber phakic intraocular lens implantation.

• All patients with high myopia undergoing intraocular refractive surgery should undergo proper retinal periphery screening and laser of suspicious lesions preoperatively.