To improve the visual acuity of patients with age-related macular degeneration (AMD), a variety of external optical magnifiers and electronic enhancement systems are used. Although in some cases they provide very good results, they are in general inadequate, both functionally and cosmetically, for many patients. A surgical alternative for magnification is low-vision intraocular device implantation, which offers promising functional results alongside the obvious cosmetic improvements.

The most commonly used low-vision device, the intraocular miniaturized telescope (IMT), confines the area of vision to a 20-degree angle at the central visual field and relies on the fellow eye to preserve the peripheral visual field. This, in my opinion, is not ideal. By contrast, the IOL-VIP (intraocular lens for visually impaired people) system, first presented in Florence in 2003,¹ offers a better alternative. It does not compromise the peripheral visual field (leaving an area of approximately 80º) and can be implanted in both eyes, maintaining binocular vision.

Figure 1

The system reproduces an intraocular Galilean telescope; it consists of a biconcave high-minus power IOL (-64 D) for the eyepiece of the telescope (implanted in the capsular bag) and a biconvex high-plus power IOL (+53 D) for the objective of the telescope (implanted in the anterior chamber) (Figure 1).

Testing the IOL-VIP system

A cross-discipline group of researchers from both the Medical University and the Physics University of Valencia² presented a pilot study of the IOL VIP system in a series of 19 eyes at the 2008 ESCRS meeting in Berlin.³ The data gained from this pilot study were compared with the theoretical values obtained in a previous study.⁴

Figure 2

The surgical technique for implanting the IOL VIP system consists of a standard cataract phacoemulsification, performed through a 3.2 mm limbal incision, a wide capsulorhexis (6–7 mm) and, to minimize postoperative astigmatism, a scleral tunnel of 8 mm at 2 mm from the limbus and at 12 o'clock. The biconcave lens is then introduced in the capsular bag; the pupil is constricted with acetylcholine and the biconvex lens is implanted in the anterior chamber angle (Figure 2). A peripheral iridotomy is performed and the scleral incision is sutured with 10-0 nylon. Finally, cefuroxime is injected intraocularly. For four weeks postoperatively, drops of ciprofloxacin and dexamethasone are used in a tapering system.

The cornea:anterior chamber lens distance and the anterior chamber lens:posterior chamber lens distance were both evaluated with high-frequency ultrasound biomicroscopy (UBM). Endothelial cell count was measured using a specular microscope preoperatively and 18 months postoperatively.

No complications were observed

Of the 19 patients enrolled in the pilot study, no cases of intraoperative or postoperative complications were detected, and no patients presented severe adverse effects. Four patients presented increased intraocular hypertension and a mild sectorial corneal oedema, controlled with topical timolol maleate. Only three patients developed posterior capsular opacification during the course of the study, which were treated with neodymium YAG laser. A single patient requested removal of the device after experiencing what was subjectively and confusedly described as a "strange situation" mixed with dizziness, but without diplopia. The refractive results in this patient were satisfactory; nevertheless, both lenses were removed and a standard monofocal lens was reimplanted.