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Inside Eyetube.net | Jul/Aug 2013

Proper Considerations for IOL Selection

Four characteristics are important when selecting a lens for patients with retinal pathologies.

The surgeon must consider several key issues when selecting an IOL for a patient with retinal pathology. Most important, because of the associated compromise in visual potential with retinal pathology, it is just as crucial for these patients to understand the goal of surgery as it is for the surgeon to establish realistic expectations. I have found the following checklists to be useful.

CHECKLIST FOR PREOPERATIVE COUNSELING AND EVALUATION

Item No. 1: Visual potential and disease progression. Thorough preoperative counseling should be done with the patient’s family present. The surgeon must prepare the patient for potentially suboptimal vision and disclose the possibility for the existing retinal disease to progress after cataract surgery.

Item No. 2: Expectations. The surgeon must help the patient set realistic visual expectations and discuss potential visual outcomes in relation to the patient’s lifestyle requirements, personality, and desire for spectacle independence.

Item No. 3: Evaluations. Detailed anterior and posterior segment evaluation is mandatory. In the anterior segment, the surgeon should pay close attention to the integrity and clarity of the posterior capsule and the integrity of the zonules. Often, eyes that have undergone vitrectomy have thick posterior capsular plaque and diffuse zonular weakness.

Retinal evaluation should include examination with an indirect ophthalmoscope and detailed macular assessment. Optical coherence tomography (OCT) is helpful for identifying preexisting macular pathologies that can otherwise be missed on clinical examination. Estimating visual potential is also recommended. This can be achieved with tools such as the Lotmar Visometer (discontinued; formerly by Haag-Streit) or a potential acuity meter. Although the sensitivity and specificity of these tools are not the best, their measurements can serve as rough guides in estimating visual potential.

CHECKLIST FOR IOL SELECTION

Owing to the compromises in visual quality associated with premium IOLs, these devices should be cautiously advised in eyes with retinal pathologies. My IOL platform of choice is the AcrySof (Alcon), as it has an ideal combination of the following four characteristics.

Item No. 1: Compatible with microincision cataract surgery. Phacoemulsification through a small incision offers the advantage of maintaining a closed chamber at all times.1,2

Item No. 2: Favorable anterior capsular opacification (ACO) and posterior capsular opacification (PCO) rates. Nd:YAG capsulotomy is associated with an increased risk for macular hole formation and retinal detachment. Therefore, in eyes with preexisting retinal pathologies, it is essential to select an IOL with a material and design associated with low PCO and ACO rates. Studies have shown the following materials (in order of preference) have low ACO and PCO rates: hydrophobic acrylic,3,4 hydrophilic acrylic, silicone, and PMMA (Figure 1). Additionally, the IOL should have a square edge design to minimize PCO.

Item No. 3: Compatible with silicone oil. In eyes that have undergone or are likely to undergo retinal surgeries with silicone oil injection, avoid implanting a silicone IOL. In our experience, the hydrophobic acrylic material of the AcrySof IOL platform is the most compatible with silicone oil (Figure 2).

Item No. 4: Excellent stability. Often, cataracts that develop in eyes after vitrectomy with silicone oil have associated dense plaques. In these situations, the surgeon may have to perform a primary posterior capsulectomy (Figure 3), as the thick fibrotic plaques are not amenable to Nd:YAG capsulotomy. Therefore, an IOL that can be safely implanted with an opening in the posterior capsule and that will maintain excellent long-term stability is desirable. If the IOL cannot be placed safely in the bag, plan for ciliary sulcus implantation of a three-piece IOL. A onepiece design should never be placed in the ciliary sulcus, as the thick haptics of these IOLs can cause iris and ciliary body irritation. In eyes with high myopia, consider leaving the patient aphakic if in-the-bag IOL implantation cannot be achieved safely.

CONCLUSION

My last pieces of advice are:

  • In eyes with high myopia, aim for slight myopia; and
  • In silicone-filled eyes, consider future removal of silicone oil and plan the IOL power and target refraction accordingly.

To summarize, the ideal IOL for eyes with retinal pathologies is one that is compatible with microcoaxial phacoemulsification, has favorable ACO and PCO ates, and achieves long-term stability.

Abhay R. Vasavada, MS, FRCS, is the Director of Raghudeep Eye Clinic, Iladevi Cataract & IOL Research Centre, Gujarat, India. Dr. Vasavada did not provide financial disclosure information. He may be reached at e-mail: icirc@abhayvasavada.com.

  1. Vasavada V, Vasavada, V, Raj SM, et al. Intraoperative performance and postoperative outcomes of microcoaxial phacoemulsification. Observational study. J Cataract Refract Surg. 2007;33(6):1019-1024.
  2. Osher RH. Microcoaxial phacoemulsification Part 2: Clinical Study. J Cataract Refract Surg. 2007;33(3):408-412.
  3. Shah SK, Praveen MR, Koul A, et al. Impact of anterior capsule polishing on anterior capsule opacification after cataract surgery: a randomized clinical trial. Eye. 2009;23(8):1702-1706.
  4. Vasavada AR, Shah A, Raj SM, et al. Prospective evaluation of posterior capsule opacification in myopic eyes 4 years after implantation of a single-piece acrylic IOL. J Cataract Refract Surg. 2009;35(9):1532-1539.

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