Editor, The implantation of acrylic intraocular lenses (IOLs) is popular due to their increased biocompatibility and the decreased incidence of posterior capsule opacification. Three-piece acrylic lens explantation is most commonly performed due to glare or optical aberration (Mamalis 2000). Incorrect lens power is the second most common reason for explantation, as dislocation occurs infrequently with these lenses (Mamalis 2000). Glistenings within the lens optic have also been reported in Acrysof® acrylic lenses but the severity has not been such to warrant lens explantation (Dhaliwal et al. 1996). We demonstrate a safe technique to explant an Acrysof lens without wound enlargement. A 53-year-old woman was referred to the anterior segment service for an opinion regarding her symptomatic anisometropia. She had undergone uncomplicated phacoemulsification and IOL insertion in the left eye 6 months earlier. She was pseudophakic in the right eye from a cataract operation 2 years previously. Unaided visual acuity (VA) was RE 6/6 and LE 6/36. Anterior segment examination of both eyes was unremarkable. She had an intracapsular polymethylmetnacrylate (PMMA) rigid lens in the right eye and an Acrysof MA60BM lens in the capsular bag in the left eye. Fundal examination in both eyes was unremarkable. Best corrected VA in the left eye was 6/6 with a refraction of + 2.5/− 0.5 axis 15. The intraocular power of the lens in the left eye was 21.5 dioptres. The subject underwent a repeat biometry using an IOL master (Zeiss, Welwyn Garden City, Hertfordshire, UK). Intraocular power calculation using SRK/T formulae showed that a lens power of 25.5 D would be needed in the left eye to achieve emmetropia (− 0.31). Options that were considered included: conservative management, lens exchange, piggyback IOL implantation or hyperopic LASIK. In view of the patient's symptoms, she opted for an IOL exchange under general anaesthesia. A 3.2-mm superior corneal incision was made and the anterior capsule freed from the IOL using a combination of viscodissection using Healon GV and an iris repositor. The capsular bag was then inflated with Healon GV and the IOL was rotated to ensure that haptic capsular adhesion had been broken. The IOL was then dialled out of the bag and the leading haptic was pulled through the incision and removed with MacPherson forceps. The optic was then incised with a radial cut using Ongs scissors (Fig. 1A). The lens was then embedded in the edge of the incision so that half the lens was in the eye and half out (Fig. 1B). It was then rotated using the centre of rotational axis in the edge of the incision with Mac Pherson forceps (Fig. 1C). As the optic was removed the remaining haptic followed it out of the eye. A pre-warmed 25.5 D MA60BM (13-mm length, 6-mm optic) Acrysof lens was folded and inserted into the capsular bag and the remaining viscoelastic was removed. The wound was checked to be watertight and the patient received a subconjunctival antibiotic and steroid injection. Intraocular lens removal by (A) incision, (B) embedding of the lens in the edge of incision, and (C) rotation of IOL, allowing for delivery of the remaining optic and inferior haptic. Two hours after the operation, the subject's unaided vision had improved to 6/6 in the left eye. At the 2-week follow-up there was minimal intraocular inflammation and vision was 6/5 unaided. An important consideration in the final outcome of a patient undergoing lens explantation is the preoperative VA. Patients who have an initial VA of 6/12 or more have a better clinical outcome after IOL removal or exchange. Early intervention is thought to result in a better postoperative result (Mamalis et al. 1991), as was the case in our patient. Of patients undergoing explantation of three-piece acrylic lenses, more than 93% have shown final postoperative vision of 6/6–6/9 (Mamalis 2000). Several methods of explanting acrylic foldable lenses have been described. The easiest involves extending the wound to 6 mm and removing the IOL, but this would reverse the advantages of small incision surgery (Lyle & Jin 1996). Bisecting an IOL completely (Koo et al. 1996) allows removal without enlargement of the wound but risks compromising the corneal endothelium and posterior lens capsule. Intraocular folding allows preservation of the IOL and the wound, but involves extensive manipulation incisions and may cause more damage to clear corneal incisions and a 25% reduction in the corneal endothelial cell count (Neuhann 1996). Lens disassembly followed by squeezing the lens through an incision (Geggel 2000) is possible through the scleral tunnel. We used an adaptation of a technique to remove a foldable silicone lens described by Batlan & Dodick (1996). These authors also cut the lens to its midpoint but were then able to deform the silicone optic and pull the lens through the incision. However, this is not possible with the Acrysof lens due to the more rigid structure of the hydrophobic acrylic material, which is less malleable than the silicone described by Batlan & Dodick (1996). In view of this, the technique previously described with a silicone IOL was adapted to engage the Acrysof lens against the edge of the incision and then rotate it out of the eye (Fig. 1C). The integrity of the original wound or posterior capsule is not compromised with this technique, thus ensuring that the benefits of small incision surgery are maintained. The material from which this letter was drawn was extracted from a video presentation at the Royal College of Ophthalmologists Annual Congress, May 2003, Birmingham, UK.
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Mehta et al. (2005) studied this question.