When cataract surgeons face a case that requires IOL explantation and exchange, many important issues must be addressed. Before choosing the replacement lens, the surgeon must gain the patient’s confidence because he or she is likely unhappy about needing to undergo an unanticipated procedure. The preoperative examination must be done carefully to obtain the right diagnosis to justify IOL explantation and to explain all relevant issues to the patient. The next step is to choose the right replacement lens based on the patient’s complaint, which may be due to residual ametropia, inflammation, IOL dislocation or decentration, or optic zone opacification.1,2 Factors that must be considered when choosing a replacement IOL include the integrity of the capsular bag, the optical behavior of the lens, and whether the replacement IOL should provide multifocality.
CAPSULAR BAG INTEGRITY
Intact capsular bag. In the case of an intact capsular bag, it is possible to replace the lens with a posterior chamber IOL in the same position. Extra care must be taken not to damage the integrity of the capsular bag during the exchange. The surgeon may choose to implant a one- or three-piece IOL in the capsular bag.
Partial capsular support. It is crucial to correctly judge the remaining capsular support to avoid undesired IOL decentration or posterior dislocation into the vitreous cavity. In case of partial capsular support, choose a three-piece posterior chamber IOL with an overall diameter of 13.5 or 14.0 mm and implant it in the sulcus. In these eyes, a onepiece lens is not well indicated due to the high risk for anterior uveitis with pigment dispersion and glaucoma.
Lack of capsular support. The surgeon has three lens replacement options in these cases: (1) sclerally fixate a posterior chamber IOL with eyelets on the haptics or perform sutureless intrascleral posterior chamber fixation with a three-piece posterior chamber IOL,3 (2) implant an iris-fixated one-piece IOL, such as the Artisan (Ophtec BV, Groningen, Netherlands),4 or (3) choose an angle-supported anterior chamber IOL. Before any of these procedures can be performed, complete removal of any prolapsed anterior vitreous must be achieved. Anterior chamber IOLs have been associated with a high incidence of postoperative complications such as uveitis-glaucoma-hyphema (UGH) syndrome, corneal decompensation, and macular edema.5
IOL OPTICAL PERFORMANCE
Sometimes explantations are needed because patients are unhappy with their postoperative outcomes even though the surgery was uneventful. The most common complaints are dysphotopsias and residual ametropia.
Dysphotopsias. These are unwanted images that can be positive (halos and glare) or negative (a dark shadow in the temporal visual field). These symptoms are associated with square-edged IOLs (monofocal or multifocal) and with large pupil diameters. In these cases, it is highly recommended that the surgeon wait at least 6 months before exchanging the IOL because patients generally adapt to the dysphotopsias or they disappear. During that period, the patient can be treated with brimonidine tartrate to inhibit physiologic mydriasis and limit the size of the pupil area. If after 6 months an IOL exchange is necessary, we recommend implanting a round-edged monofocal IOL with a large optic zone.5
Residual ametropia. Residual ametropia causes blurriness, affecting patients’ UCVA. It may be diagnosed early in the first postoperative week after routine cataract surgery through an incision of 2.75 mm or smaller. Residual ametropia is not well tolerated in patients with multifocal IOLs. In these situations, the surgeon can: (1) wait until the first postoperative month or later and perform refractive laser surgery, (2) implant a piggyback IOL in the sulcus using a three-piece posterior chamber IOL or one-piece IOL such as the Sulcoflex (Rayner Intraocular Lenses, Ltd., East Sussex, United Kingdom),6 or (3) avoid anterior segment inflammation by exchanging the IOL. The IOL calculation for all three scenarios must be done with extra care, using reliable formulas. The calculation for the Sulcoflex is performed using software on Rayner’s Web site (www.rayner.com).
When the anatomy of the capsular bag and anterior chamber are well maintained, the surgeon may offer to correct residual ametropia and pseudophakic presbyopia with a multifocal IOL during refractive lens exchange. This can be accomplished either by piggybacking with the Sulcoflex Multifocal IOL or by exchanging the initial implant for a multifocal IOL. The latter technique requires additional manipulation and may be more challenging to perform several months or years after the primary surgery because the capsular bag becomes fibrotic with time and the IOL more attached to the posterior capsule.
Surgeons have multiple replacement IOLs to choose from to solve dissatisfied patients’ discomforts. The surgeon’s final choice will depend primarily on the anterior segment anatomy and on the patient’s desired focus. A thorough preoperative examination and an uneventful surgical procedure are mandatory for success.
Daniela M.V. Marques, MD, PhD, is a Medical Director of the Marques Eye Institute and Medical Collaborator at the Institute of Cataract, UNIFESP, Sao Paulo, Brazil. She is also Medical Collaborator at the Complexo Hospitalar Padre Bento, Guarulhos, Brazil. Dr. Marques states that she has no financial interest in the products or companies mentioned. She may be reached at tel: +55 11 5677 3513; e-mail: email@example.com.
Frederico F. Marques, MD, PhD, is a Medical Director of the Marques Eye Institute, Sao Paulo, Brazil and Medical Collaborator at the Complexo Hospitalar Padre Bento, Guarulhos, Brazil. Dr. Marques states that he has no financial interest in the products or companies mentioned. He may be reached at tel: +55 11 5677 3513; e-mail: firstname.lastname@example.org.
- Marques FF,Marques DM,Osher RH,Freitas LL.Longitudinal study of intraocular lens exchange.J Cataract Refract Surg. 2007;33(2):254-257.
- Mamalis N,Brubaker J,Davis D,Espandar L,Werner L.Complications of foldable intraocular lenses requiring explantation or secondary intervention:2007 survey update.J Cataract Refract Surg.2008;34(9):1584-1591. Gabor SG,Pavlidis MM.Sutureless intrascleral posterior chamber intraocular lens fixation.J Cataract Refract Surg. 2007;33(11):1851-1854. Riazi M,Moghimi S,Najmi Z,Ghaffari R.Secondary Artisan-Verysise intraocular lens implantation for aphakic correction in post-traumatic vitrectomized eye.Eye.2008;22(11):1419-1424. Marques FF,Marques DM.Unilateral dysphotopsia after bilateral intraocular lens implantation using the AR40e IOL model: case report.Arq Bras Oftalmol.2007;70(2):350-354. Kahraman G,Amon M.New supplementary intraocular lens for refractive enhancement in pseudophakic patients.J Cataract Refract Surg.2010;36(7):1090-1094.