New surgical techniques performed in conjunction with the latest IOL models have significantly reduced the incidence of complications associated with cataract surgery. The need for an IOL exchange is occasional, and surgeons must be familiar with the principles and techniques of lens exchange to avoid causing extra trauma to the eye.
My colleagues and I performed a retrospective study of 49 eyes (49 patients) that underwent IOL exchange between 1988 and 2002 at the Cincinnati Eye Institute, in Ohio. Robert H. Osher, MD, Professor of Ophthalmology, at the University of Cincinnati College of Medicine, performed all IOL exchanges. We studied the main indications of IOL exchange and analyzed its complications, techniques, interval between surgeries, and preoperative and postoperative BCVA. Patients were separated into two groups according to the originally explanted IOL. Fifteen patients were categorized into the anterior chamber IOL (ACIOL) and 34 into the posterior chamber IOL (PCIOL) group. There was no statistically significant difference regarding patient age between groups. All data were analyzed using the Fisher, Qui2, Mann-Whitney test, or Student t-test. We considered any P value less than .005 to be significant.
RESULTS
Mean follow-up was 40.9 months in the ACIOL group and 36.2 months in the PCIOL group, and the mean interval between surgeries was 83.2 months and 37.9 months in the ACIOL and PCIOL groups, respectively. There were no statistically significant differences between groups (Table 1). The postoperative BCVA was either the same or improved in both groups, with no statistically significant difference in homogeneous behavior (Table 2).
ACIOL group. Eighty percent of patients achieved a postoperative BCVA of 20/40 or better, and the main indications for IOL exchange were chronic macular edema (n=5, 33.34%); persistent iritis (n=4, 26.67%); and uveitis, glaucoma, hyphema (UGH) syndrome.
All explanted IOLs were made of PMMA, and the major operative challenge was adherent fixation of the haptics. Five eyes (33.3%) required haptic cutting or fracturing with either scissors (n=1) or Nd:Yag laser (n=4) (Figure 1). Anterior vitrectomy was performed in 12 eyes (80%), three eyes (20%) experienced cystoid macular edema, and one eye (6.7%) experienced pseudophakic bullous keratopathy.
PCIOL group. In the PCIOL group, 79.4% achieved a postoperative BCVA of 20/40 or better. The main indications for IOL exchange were decentration/dislocation (n=29 eyes, 85.3%), followed by refractive error (n=2, 5.7%).
In this group, explanted IOLs were either made of PMMA (n=26, 76.5%) or silicone (n=8, 23.5%). Only three eyes had IOL haptic fracture by scissors, but an anterior vitrectomy was required in 21 eyes (61.8%). Postoperative complications included glaucoma (n=2, 5%) that was controlled with medication, vitreous hemorrhage, and pseudophakic bullous keratopathy (n=1, 3%). One case developed a retinal detachment 36 months after surgery.
CONSIDERATIONS
The IOL exchange procedure is always challenging, and surgeons must be familiar with the proper technique for IOL removal according to the lens material. By choosing the proper method, it is possible to induce less trauma into the eye. For silicone IOLs, you may work with the traditional 3-mm incision by cutting it. For foldable acrylic IOLs, work with the same incision length, but cut or fold the lens inside the eye. By contrast, if you have a PMMA IOL, make the incision as large as its optical zone.
Choose the replacement IOL while keeping several factors in mind. First, the IOL size should coincide with the incision size needed for removal of the original IOL. Second, the IOL must be supported by integrity of the capsular bag, and third, the surgeon must remember the presence of capsule support. This will guide the surgeon to perform the implantation on the sulcus, supported by the remaining capsule or IOL fixation to the scleral wall. A PCIOL should always be considered as the first choice, however, an ACIOL may be chosen for patients with healthy iris tissue and an anterior chamber depth greater than 3 mm. Moreover, the presence of vitreous in these procedures is common, and an anterior vitrectomy should be carefully planned.
The main indication for IOL exchange was inflammatory (ie, UGH syndrome, cystoid macular edema, persistent iritis) in the ACIOL group and decentration/dislocation in the PCIOL group. The interval between surgeries was longer in the ACIOL group compared with the PCIOL (83.2 months vs 37.9 months, respectively). This correlation is due to the early problems related to IOL positioning and the visual discomfort associated with IOL decentration/dislocation. Alternately, inflammatory symptoms are usually slow and progressive. The BCVA after the IOL exchange was similar in both groups, and it was better than or equal to preoperative levels in 80% of cases.
In conclusion, when the surgeon faces a case of possible IOL exchange, it is important to carefully consider its possible benefits against the patient's condition. Once it is well indicated, IOL exchange is a relatively safe procedure with low incidence of complications. Patients should regain visual comfort in the majority of the cases.
Frederico F. Marques, MD, PhD, is in private practice at the Marques Eye Institute, in São Paulo, Brazil, and Fellow of the Institute of Cataract at the Federal University of São Paulo, in Brazil. Dr. Marques states that he has no financial interest in the products or companies mentioned. He may be reached at fredani2010@terra.com.br.
