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Approaching the macula from the premium cataract surgeon perspective

Issue: August 10, 2016

ByMitchell A. Jackson, MD

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Premium cataract surgeons face the daily decision of whether to offer cataract surgery patients the option of multifocal IOL or other advanced IOL technology, which could contribute to current and/or future potential undesirable visual aberrations postoperatively. Patients may present at their initial cataract evaluation with a pristine macula or early pathology such as an epiretinal membrane or mild macular degeneration. Even with a normal macula, the potential for macular pathology in the future is essentially unknown without specialized diagnostic approaches to improve our detection and/or prediction odds. The decision to go with monofocal IOL technology with zero aberrations, such as the hydrophobic acrylic enVista MX60 from Bausch + Lomb, is much easier in patients with moderate or severe macular pathology.

The prevalence of AMD is 9.2 million Americans, occurring in seven out of every 100 adults older than 40 years, one out of eight older than 60 years, and one out of three older than 75 years. AREDS2 nutritional supplementation can lower the risk of progression by 25%, and certain behavior modifications such as less smoking, better cardiovascular status, increased exercise and improved diet can also lessen the risk of progression. Obviously, as premium cataract surgeons we cannot control compliance for our patients with such options, and so utilizing current and other upcoming diagnostic and therapeutic technologies described below can only improve the odds.

Electrophysiology

Devices that measure a pattern ERG (PERG) in the office, such as systems from Diopsys, are an excellent way to determine objective disturbances to the ganglion cells at an early stage of disease, such as patients with hydroxychloroquine toxicity or glaucoma. More recently, Diopsys added to its electrophysiological profile the ability to measure potential macular cone function in patients with dense media opacities such as mature and/or dense nuclear sclerotic cataracts with flash or flicker ERG (FERG). Both fixed and multi-luminance FERG testing, totaling 100 seconds for both tests on both eyes in patients with dense cataracts (limited to no view by fundus ophthalmoscopy and/or OCT testing), can aid the premium cataract surgeon in educating the patient whether to proceed with cataract surgery or not for vision recovery purposes.

Macular pigment and genetic testing

Both genetic testing and measurement of macular pigment optical density (MPOD) (Guardion Health Sciences) can indicate a heightened risk for development of AMD. Awh and colleagues created a genetic test to evaluate CFH (located on chromosome 1q31) and ARMS2 (located on chromosome 10) genes, and performed retrospective analyses of AREDS subgroups. They claimed that treatment with the AREDS supplements should be tailored according to the patient’s genotype, suggesting the need to genotype all patients taking the AREDS supplements. Genetic testing is still controversial in its value to eye care professionals, but those available from Macula Risk (ArcticDx) and RetnaGene AMD (Sequenom) can provide insight on the progression risk of AMD with a simple in-office cheek swab test and analysis of risk factors such as family history of AMD and smoking history.

Macular pigment is a measure of retinal oxidative stress (including the phototoxic effects of blue light exposure) known as the MPOD measurement taken by Guardion’s MAPCATsf densometer. Macular pigment is potentially a modifiable risk factor for AMD through patient consumption of “medical food” such as Lumega-Z (Guardion), which has an FDA-regulated Medical Food Status (per section 5(b) of the Orphan Drug Act) specifically for the purpose of replenishing and restoring depleted macular pigment. Lumega-Z contains the third critical patented carotenoid meso-zeaxanthin and 32 other micronutrients to maintain a healthy macular pigment, which can continually be monitored and repeatedly measured with the densometer.

Dark adaptation

A functional test for dark adaptation may allow for earlier detection of AMD than structural tests that are the current standard. A recently published clinical study concluded that impaired rod-mediated dark adaptation in older adults with normal macular health is associated with incident early AMD 3 years later. Another study concluded that that same technology for measuring rod-mediated dark adaptation had a high 90% sensitivity and 90% specificity. This technology has been commercialized by MacuLogix in an instrument called the AdaptDx. MacuLogix was able to enhance its dark adaptation technology to offer a practical and easily administered in-office 6.5-minute test.

Newer therapeutic approaches

Lastly, the Implantable Miniature Telescope (IMT, CentraSight, VisionCare Ophthalmic Technologies) is a form of a lens implant placed in patients with end-stage AMD, and it allows for enlarged images 2.7 times their normal size in front of the patient’s eye. The realistic goals to be achieved with patients with this device in only one eye and a standard IOL in the opposite eye are to be able to read headlines, recognize faces and/or watch television when none of these functions were possible before implantation of the device. The placement of the device requires extensive preoperative and postoperative coordination of care by a premium cataract surgeon, a low vision specialist, a vitreoretinal specialist and an occupational vision therapist. A gain of three lines or more of best corrected distance visual acuity 2 years after the IMT was placed was observed in one of the pivotal clinical trials.

Lastly, an alternative way for patients to utilize AREDS/AREDS2 nutraceutical supplementation for early AMD is the use of OJO (OJO Nectar), a liquid form of the more common oral pill formulations such as Ocuvite (Bausch + Lomb), PreserVision (Bausch + Lomb) and ICaps (Alcon). OJO comes in a juice form and crystal packets to mix in with a patient’s favorite drink to enhance compliance for those patients who are unable to swallow large pills and/or capsules.

• References:
• Age Related Eye Disease Study Research Group. Arch Ophthalmol. 2001;doi:10.1001/archopht.119.10.1417.
• Awh CC, et al. Ophthalmology. 2013;doi:10.1016/j.ophtha.2013.07.039.
• Bernstein PS, et al. Prog Retin Eye Res. 2016;doi:10.1016/j.preteyeres.2015.10.003.
• Hudson HL, et al. Am J Ophthalmol. 2008;doi:10.1016/j.ajo.2008.07.003.
• Jackson GR, et al. Invest Ophthalmol Vis Sci. 2014;doi:10.1167/iovs.13-13745.
• Owsley C, et al. Ophthalmology. 2016;doi:10.1016/j.ophtha.2015.09.041.
• Pérez-Salvador García E, et al. Arch Soc Esp Oftalmol. 2002;77(10):543-551.
• Ratanapakorn T, et al. J Med Assoc Thai. 2010;93(10):1196-1199.
• Roberts JE, et al. J Ophthalmol. 2015;doi:10.1155/2015/687173.
• Sabour-Pickett S, et al. Mol Nutr Food Res. 2012;doi:10.1002/mnfr.201100219.

• For more information:
• Mitchell A. Jackson, MD, can be reached at Jacksoneye, 300 N. Milwaukee Ave., Suite L, Lake Villa, IL 60046; email: mjlaserdoc@msn.com.

Disclosure: Jackson reports he is a consultant for Diopsys, Bausch + Lomb and VisionCare.