Severe prelenticular membrane formation on the surface of a hydrophilic acrylic intraocular lens after cataract surgery in an eye with an Ahmed valve implant.

Dear Sir, I am Yong-Sun Ahn, from the Department of Ophthalmology of St. Vincent Hospital of Suwon, Kyungki-do, South Korea. Cataracts are a common problem in eyes with a glaucoma drainage device (GDD), because tube shunt surgery increases the incidence and progression of cataracts [1]. An Ahmed valve, the most commonly inserted GDD, is composed of a silicone tube connected to a flat plate sewn to the sclera, and aqueous humor flows from the anterior chamber through the tube onto the plate to form a subconjunctival bleb [2]. Although cataract surgery in eyes with a functioning GDD is generally safe, with less detrimental effect on intraocular pressure (IOP) control, compared to eyes with a functioning bleb. However, little is known of the interaction of a pre-existing silicone valve in the anterior chamber with the intraocular lens (IOL) material, and the effects on postoperative inflammation compared to standard phacoemulsification. Hydrophilic acrylic IOLs are very biocompatible, with the smallest foreign body reactions, compared to other foldable IOLs . In terms of the interaction with other lens materials, however, increased calcification has been reported when they are exposed to silicone compounds. We experienced a case of a severe prelenticular membrane formation on the surface of an MI60 hydrophilic acrylic IOL after uneventful clear corneal phacoemulsification in an eye with an Ahmed valve implant. After replacing the IOL with a silicone IOL, the inflammation subsided. The prelenticular membrane and explanted IOL were sent for histopathological analysis and examined using transmission electron microscopy (TEM), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). And this study was performed with informed consent and following all the guidelines for experimental investigations required by the Institutional Review Board or Ethics Committee of St. Vincent Hospital. A 51-year-old man with a 5-year history of diabetes mellitus had an Ahmed glaucoma valve (AGV-FP7) implanted superotemporally with a sclera graft in his left eye for neovascular glaucoma. About 8mo later, he presented with blurred vision in his left eye. He had a dense grade 5 posterior subcapsular cataract [NO2, NC2, C3, P5 according to the Lens Opacities Classification System III ( 1993;111(6):831-836)], and the IOP was 17 mm Hg without anti-glaucoma eyedrops. The corrected distance visual acuity (CDVA) was 1.39 logMAR in the left eye. He had uneventful cataract surgery with implantation of a hydrophilic acrylic IOL (MI60, Bausch and Lomb, USA). A dispersive ophthalmic viscosurgical device [sodium chondroitin sulfate 4-sodium hyaluronate 3% (Viscoat)] was used. On the day following surgery, the CDVA had improved to 0.52 logMAR The eye was treated with moxifloxacin 0.5% ophthalmic solution and dexamethasone 0.1% ophthalmic suspension four times a day. The cornea was clear with a trace of cellular activity. No postoperative complications such as fibrin formation or IOP elevation were observed. Five days later, the patient visited the clinic complaining of a sudden reduction in vision 3d after the surgery, and a CDVA of 1.69 logMAR. Some corneal edema was present, along with 1+ cellular activity and a thick white opacification was observed on the anterior IOL surface, which completely covered the capsulorhexis opening (Figure 1A). At 10d, the CDVA had not improved, so the IOL was replaced with a second-generation silicone foldable IOL (SoFlex Li61U, Bausch and Lomb, USA). After this, the inflammation subsided. One month later, the CDVA had improved to 0.69 logMAR and 6mo later, to 0.39 logMAR (Figure 1B). 窑Letter to the Editor窑 Prelenticular membrane formation in an Ahmed valve implanted eye