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Cataract surgery pearls for patients with AMD
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 Uday Devgan |
While there are multiple new treatments available or on the horizon for age-related macular degeneration, it remains a disease that can severely limit the vision of our patients. Combined with concurrent cataracts, the resultant decrease in vision is even more significant and the visual disability even worse. Performing cataract surgery removes the lens opacities from the visual axis, which will help the retina specialist monitor the subtle macular changes and, more importantly, help the patient with improved vision.
Because cataracts and macular degeneration are age-related, they tend to happen concomitantly in our older patients. In the past, studies suggested that the odds of having macular degeneration were higher after cataract surgery than before surgery. This may be flawed reasoning because both cataracts and macular degeneration increase progressively with age, and detection of subtle macular changes may be impaired when the retina specialist is looking through the opacities of the cataract. Multiple newer studies have demonstrated that cataract surgery does not cause progression of macular degeneration, and in fact, it will likely improve vision in these patients.
Surgical planning and technique
The goal of cataract surgery should be to remove that cataract but also to correct any refractive errors. For example, significant astigmatism will degrade the image quality projected onto the retina, so it should be treated at the time of cataract surgery. While the most common postoperative goal is emmetropia, there are arguments that residual myopia may give the patient the benefit of a near focal point and that residual hyperopia, when treated with spectacles, may provide additional image magnification
It can be argued that there is an inflammatory component to macular degeneration, so using a minimally invasive technique with smaller incisions, less ultrasound energy and an efficient technique is beneficial to these patients. In addition, performing cataract surgery while the lens opacities are moderate rather than severe may help to minimize further inflammation in the postoperative period. Use of topical steroids and NSAIDs after surgery is beneficial as well. In patients with significant macular disease, there may be a higher risk of postoperative cystoid macular edema, so continuation of topical NSAIDs until macular thickness is noted to be at baseline is advised after surgery.
If patients need intravitreal injections of anti-VEGF medications, these can be given at the same time as cataract surgery. After the IOL is implanted and the viscoelastic is aspirated, the incisions are sealed and a pars plana injection can be administered.
IOL selection
Patients with macular degeneration are usually best served by implantation of a lens with a monofocal optic as opposed to a multifocal optic. Because the incoming light is split by a multifocal lens, the contrast sensitivity is decreased, which may limit the vision due to the already impaired macula. Toric lenses and accommodating lenses, which incorporate monofocal optics, can be appropriate choices as well. In eyes in which future retinal surgery is anticipated, use of an acrylic IOL may facilitate maneuvers during a pars plana vitrectomy.
 Figure 1. A patient with age-related macular degeneration and cataracts. While the wet and dry macular degeneration affects the central vision, the cataracts blur the entire visual field, including both central and peripheral vision. Images: Devgan U |
 Figure 2. Doing cataract surgery in this patient with macular degeneration will result in a mild increase in central visual acuity but a larger increase in peripheral vision. Studies show that cataract surgery can improve the vision of patients with macular degeneration, without a risk of disease progression. |
It has been postulated that perhaps the opacities of the cataract block blue light and that a clear lens implant after cataract surgery may allow higher-energy blue light to hit the macula, which may induce progression of macular degeneration. While all IOLs block UV light, there are some lens implants that also filter higher-energy visible light, such as violet and blue. Bausch & Lomb has a violet-filtering chromophore on its SofPort line of three-piece silicone IOLs. Alcon Laboratories has a blue-filtering chromophore on its AcrySof line of single-piece acrylic IOLs. Abbott Medical Optics has chosen to avoid chromophores in its IOLs, while Hoya Surgical Optics offers both clear and blue-filtering IOL lines.
Most studies show no significant negative effects of violet- and blue-filtering IOLs on measures of visual performance, including color perception and contrast sensitivity. While some suggest that IOLs with chromophores may interfere with circadian rhythms and scotopic sensitivity, clinical significance has not been fully determined. Similarly, while there is no direct evidence that a violet- or blue-filtering IOL will prevent progression of macular degeneration, many surgeons feel that there is no downside to their use.
In any situation, the IOL implanted at the time of cataract surgery, whether clear or with a chromophore, is likely to be far superior to the opaque, cataractous human lens that was phaco-aspirated. Patients with macular degeneration should be encouraged to undergo phacoemulsification surgery if they have significant cataracts because their vision is likely to improve considerably.
References:
- Cuthbertson FM, Peirson SN, Wulff K, Foster RG, Downes SM. Blue light-filtering intraocular lenses: review of potential benefits and side effects. J Cataract Refract Surg. 2009;35(7):1281-1297.
- Dong LM, Stark WJ, Jefferys JL, et al. Progression of age-related macular degeneration after cataract surgery. Arch Ophthalmol. 2009;127(11):1412-1419.
- Forooghian F, Agrón E, Clemons TE, Ferris FL 3rd, Chew EY; Age-Related Eye Disease Study Research Group. Visual acuity outcomes after cataract surgery in patients with age-related macular degeneration: age-related eye disease study report no. 27. Ophthalmology. 2009;116(11):2093-2100.
- Henderson BA, Grimes KJ. Blue-blocking IOLs: a complete review of the literature [published online ahead of print Oct. 27, 2009]. Surv Ophthalmol. doi:10.1016/j.survophthal.2009.07.007.
- Hooper CY, Lamoureux EL, Lim L, et al. Cataract surgery in high-risk age-related macular degeneration: a randomized controlled trial. Clin Experiment Ophthalmol. 2009;37(6):570-576.
- Mainster MA, Turner PL. Blue-blocking IOLs decrease photoreception without providing significant photoprotection [published online ahead of print Oct. 31, 2009]. Surv Ophthalmol. doi:10.1016/j.survophthal.2009.07.006.
- Uday Devgan, MD, FACS, is in private practice at Devgan Eye in Los Angeles, chief of ophthalmology at Olive View UCLA Medical Center and an associate clinical professor at the UCLA School of Medicine. Dr. Devgan can be reached at 11600 Wilshire Blvd., Suite 200, Los Angeles, CA 90025; 800-337-1969; fax: 310-388-3028; e-mail: devgan@gmail.com; Web site: www.udaydevgan.com. Dr. Devgan is a consultant to Bausch & Lomb, Abbott Medical Optics and Hoya Surgical Optics, and a stockholder in Alcon Laboratories.
