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Cataract Surgery in the Patient with AMD

 

Franco M. Recchia, MD
Associate Professor of Ophthalmology and Visual Sciences
Director, Fellowship in Vitreoretinal Diseases and Surgery
Vanderbilt Eye Institute
Nashville, TN


doctor

Management of the patient with coexisting cataract and age-related macular degeneration (AMD) presents unique challenges to the cataract surgeon, the retina specialist, and the patient. A common clinical scenario is the patient in whom both the cataract and macular pathology appear to be contributing to decreased visual acuity. Common questions are: Will cataract surgery improve the vision? Will cataract surgery make the AMD worse? Are there any special precautions to be taken?    

 

As with any surgery, the expectations from cataract removal must be evaluated thoroughly and understood clearly by both the patient and the cataract surgeon. Most patients with AMD who undergo cataract surgery feel that the surgery is worthwhile, and they report quality-of-life scores comparable to those reported by patients without AMD.1,2 In patients with mild AMD, improvement in central visual acuity and attainment of driving vision are realistic and achievable goals. In an eye with central disciform scarring or geographic atrophy, there may be potential for improvement in color discrimination, contrast, or clarity of peripheral vision. Finally, in cases of dense cataract obscuring macular detail, cataract removal may be necessary to allow for adequate biomicroscopy and angiography, especially in an eye that may be at high risk for the development of choroidal neovascularization. While it is often challenging to estimate the relative impact on visual impairment made by lens changes and macular changes (especially in intermediate cases), testing with the potential acuity meter may be helpful in estimating postoperative acuity.3

 

For many years there has been legitimate concern that cataract surgery contributes to the progression of AMD. Animal models have demonstrated macular phototoxicity in response to visible light (especially low-wavelength blue light). It has been theorized that the permissive absorption of blue light following removal of the crystalline lens may accelerate maculopathy. Additionally, growing evidence supports a pathogenic role for inflammation in AMD, and the normal inflammatory response that accompanies cataract surgery, even when uncomplicated, may be deleterious to at-risk eyes. However, epidemiologic studies to date have failed to prove definitively that cataract surgery is associated with AMD progression. In pooled data from two large, prospective, population-based studies, the prevalence of advanced AMD (geographic atrophy or choroidal neovascularization) after five years was significantly higher in nonphakic eyes than phakic eyes. Advanced AMD was observed in 6.7% of eyes that had undergone cataract surgery prior to baseline and in only 0.7% of eyes that remained phakic.4 However, in the cohort of patients in the Blue Mountains Eye Disease Study who underwent cataract surgery during the first five years of the study and were then followed up to the 10-year timepoint, there was no significantly increased risk of developing AMD after adjusting for age, gender, and smoking.5 Similarly, in the Age-Related Eye Disease Study (AREDS), patients who underwent cataract surgery over a six-year period showed no higher risk of developing advanced AMD than those who remained phakic. Most recently, in a case-control study, 696 patients with AMD were followed for at least one year after cataract surgery and compared with 202 patients with early AMD who did not have cataract surgery. The development of advanced AMD was not significantly different between the two groups. There was, however, a significant improvement in visual acuity in those patients undergoing surgery.6

 

Without clear-cut answers, there are some reasonable steps for the cataract surgeon to consider in order to optimize postoperative visual acuity: choice of intraocular lens implant (IOL); aggressive control of intraocular inflammation; and patient counseling. In an effort to reduce absorption of low-wavelength visible light and retard its damaging effects, yellow-tinted, blue light-filtering (“blue-blocking”) intraocular lens implants have been developed. While there remains no prospective, randomized clinical trial proving any protection against AMD, the use of a blue-blocking IOL is defensible on the basis of its biological plausibility and may offer significant health care savings longterm given the increasingly aging population.7 Despite concerns of diminished scotopic sensitivity and difficulties with color perception and brightness, visual function has been shown to be virtually identical in patients with yellow-tinted and standard IOLs.8 Inflammation is known to incite cystoid macular edema, but may also contribute to the progression of AMD. Preoperative treatment with topical non-steroidal anti-inflammatory drugs (NSAIDs) has been shown to stabilize the blood-retina barrier and reduce angiographic leakage postoperatively. NSAID treatment may also be beneficial in improving choroidal blood flow and stabilizing the outer blood-retinal barrier.9 Lastly, cataract surgery affords another opportunity to educate patients and their families about the environmental, dietary, and behavioral aspects of AMD management. It is never too late to discuss the benefits of smoking cessation, vitamin supplementation in cases of intermediate or advanced AMD, home monitoring with an Amsler grid, regular fundus examination, and the advisability of a complete eye examination for relatives.    

 

In summary, in the patient with a visually significant cataract, AMD should not be considered a contraindication to cataract surgery, and surgery need not be delayed for fear of causing advanced AMD. Factors such as IOL selection and perioperative management may optimize visual outcome and reduce the risk of AMD progression.

 

REFERENCES

  1. Shuttleworth GN, Luhishi EA, Harrad RA. Do patients with age related maculopathy and cataract benefit from cataract surgery? Br J Ophthalmol 1998;82(6):611-6.
  2. Pham TQ, Cugati S, Rochtchina E, et al. Age-related maculopathy and cataract surgery outcomes: visual acuity and health-related quality of life. Eye 2007;21(3):324-30.
  3. Alio JL, Artola A, Ruiz-Moreno JM, et al. Accuracy of the potential acuity meter in predicting the visual outcome in cases of cataract associated with macular degeneration. Eur J Ophthalmol 1993;3(4):189-92.
  4. Wang, JJ, Klein R, Smith W, et al. Cataract surgery and the 5-year incidence of late-stage age-related maculopathy: pooled findings from the Beaver Dam and Blue Mountains Eye Studies. Ophthalmology 2003; 110:1960-1967.
  5. Cugati S, Mitchell P, Rochtchina E, et al. Cataract surgery and the 10-year incidence of age-related maculopathy: the Blue Mountains Eye Study. Ophthalmology 2006;113(11):2020-5.
  6. Baatz H, Darawsha R, Ackermann H, et al. Phacoemulsification does not induce neovascular age-related macular degeneration. Invest Ophthalmol Vis Sci 2008;49(3):1079-83.
  7. Reddy P, Gao X, Barnes R, et al. The economic impact of blue-light filtering intraocular lenses on age-related macular degeneration associated with cataract surgery: a third-party payer's perspective. Curr Med Res Opin 2006;22(7):1311-8.
  8. Hayashi K, Hayashi H. Visual function in patients with yellow tinted intraocular lenses compared with vision in patients with non-tinted intraocular lenses. Br J Ophthalmol 2006;90(8):1019-23.
  9. Miyake K, Nishimura K, Harino S, et al. The effect of topical diclofenac on choroidal blood flow in early postoperative pseudophakias with regard to cystoid macular edema formation. Invest Ophthalmol Vis Sci 2007;48(12):5647-52.

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Ingrid U. Scott, MD, MPH,  Editor

Professor of Ophthalmology and
Public Health Sciences,
Penn State College of Medicine

 

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