A few years ago, a 65-year-old white female was referred to me for an evaluation of AMD. Although she did not have any subjective visual complaints, she showed clinical findings of intermediate AMD. These findings, obtained via SD-OCT, included soft macular drusen and a pigment epithelial detachment, though no evidence of advanced AMD or a choroidal neovascular membrane.
Dilated exam revealed multiple medium to large drusen (at least 60 µm to 63 µm in each eye). There was no evidence of pigment changes, hemorrhage, retinal edema or hard exudate seen, however.
Entering VAs measured 20/25 in each eye with best correction, and Amsler grid testing was normal without metamorphopsia in either eye.
In addition, the patient’s medical history was unremarkable (no hypertension or hypercholesterolemia), and she denied smoking. However, she said her family medical history was positive for AMD, with her mother becoming legally blind in her 70s from the condition. In fact, the patient divulged that having watched her mother lose her central vision, she was concerned with her own diagnosis of AMD and had been wearing UV lenses for the past two decades to protect her eyes.
Based on the patient’s family history and her level of concern, she said she wanted to do anything possible to learn about her risk of becoming legally blind and, therefore, consented to undergo genetic testing for AMD. The results of the testing revealed she had a 5% to 15% chance of developing advanced AMD (exudative findings or geographic atrophy) for up to 10 years — similar to the risk of the average person living in North America.
How would you manage this patient?
Here, I discuss how to manage patients who have either non-exudative (dry) or exudative (wet) AMD and how, specifically, I managed the patient above.
NON-EXUDATIVE AMD MANAGEMENT
The two ways you can effectively manage these patients: (1) Review modifiable risk factors with them, and provide action steps for overcoming them and, (2) establish a specific follow-up schedule, including education on the daily use of a home Amsler grid:
- Modifiable risk factors. The following fall under this category:
- Body mass index (BMI) greater than 30. A person with a BMI greater than 30 has a 2.5 times increased risk of developing AMD compared with those who have a lower BMI. Counseling your patient on interventions to lower their BMI is important. I suggest these patients consider the interventions of a formal diet, exercise program, and I consider a referral to a nutritionist, when applicable.
- Smoking. Smoking can increase a person’s risk of developing AMD by two to five times. It leads to oxidative damage, which may contribute to the development and progression of AMD. To manage these patients, I discuss with them the detriment of their personal smoking habits and exposure to secondhand smoke in the household. In addition, I am very proactive in discussing a means of quitting smoking, including a referral to the primary care physician with instructions to discuss a formal plan on cessation. (See http://bit.ly/2orAozc , for additional information on smoking cessation.)
- Elevated cholesterol levels. Increased total cholesterol has been recognized as a risk factor for AMD, according to an American Journal of Ophthalmology study comprised of close to 4,000 subjects. The good news: Studies show that treatment with a statin drug can reduce macular drusen size in these patients and, in some cases, drusen have actually resolved completely through time. The formation of drusen is thought to be the first clinical finding of AMD. To manage these patients, I counsel them on the importance of good nutrition and suggest treatment of elevated cholesterol levels through co-management with their primary care physician.
- Low macular pigment optical density (MPOD). Patients with a low MPOD have been found to have a higher incidence of AMD, making it a risk factor for the disease. Oxidative damage, mentioned above, is known to contribute to the pathogenesis of AMD and is related to low-grade inflammation and hypoxia, which occurs in the outer retina (photoreceptor layer and retinal pigment epithelium). The natural components of macular pigment, lutein and zeaxanthin, show potent antioxidative properties and, hence, increasing the MPOD may result in a protective factor for developing AMD. To manage patients who have AMD-related findings or numerous risk factors for the disease, I recommend supplementation of lutein and zeaxanthin, 10 mg and 2 mg respectively. (5:1 ratio).
In 2013 an extension of the AREDS1 study, the AREDS2 study, compared AREDS1 formula with one in which beta carotene was replaced with lutein/zeaxanthin. (As a brief reminder, in the AREDS1 study, it was found that smokers had a higher incidence of developing lung cancer if they took beta carotene as a supplement, so it was removed in the AREDS2.) In addition, the amount of zinc in the new formula was reduced from 80 mg to 25 mg per daily dose. That said, 25 mg is not the generally accepted level of zinc. It is one option. Many practitioners still use 80 mg, as was recommend by the NEI, as this reduction did not decrease the effects of reducing the risk of progression to advanced AMD. Thus, currently an AREDS2 vitamin with 25 mg of zinc has become an accepted supplement for patients with intermediate to advanced AMD.
- Light colored eyes. Several studies have correlated a risk for developing AMD to having a light-colored iris. In addition to recommending UV protection to these patients who have AMD, it is also advised that the children of those with AMD be proactive early in life with UV protection, especially if they have light-colored eyes.
- Specific follow-up schedule. Determining a follow-up protocol for patients who have non-exudative AMD is important in monitoring possible disease progression. My practice’s standard follow-up schedule for these patients:
- Early AMD (drusen less than 63 μm). Annual follow-up.
- Intermediate AMD (multiple medium drusen or one large drusen, 63 μm). Seen twice yearly, or every six months.
- Intermediate AMD and a pigment epithelial detachment. Seen every three to four months, as we know this patient profile carries the highest risk for progression to advanced AMD.
EXUDATIVE AMD MANAGEMENT
Once a patient is diagnosed with exudative AMD, he should be promptly referred to a retina specialist, who will assess the clinical findings and initiate treatment with one of the following anti-VEGF compounds for intravitreal injection: (aflibercept [Eylea, Regeneron], bevacizumab, [Avastin, Genentech] and ranibizumab [Lucentis, Genentech]).
A caveat: While the patient is under the care of the retina specialist, it is important to maintain scheduled follow-up visits with him for his primary care examinations. The reason: Retina specialists focus on the management of retina and macular disease and often do not have the entire ophthalmic history of the patient.
For example, a patient with glaucoma may be getting his IOP measured at the retina specialist’s office, but this is not the only value that needs monitoring to follow the disease. Gonioscopy, stereoscopic disc photos, evaluation of retinal nerve fiber and ganglion cell thickness with SD-OCT imaging and visual fields are also indicated.
It is not uncommon for patients to get the impression that they no longer need to see their optometrist while they are under the care of the retina specialist, however, this, in fact, is untrue and should be communicated to these patients. When the referral is made to the retina specialist, educate patients on the continued need for follow-up with you, their primary eye care provider. Consider scheduling them for a follow-up appointment, even if an annual examination is all that is needed.
In addition, being able to recognize the ophthalmic signs and SD-OCT findings consistent with active or recurrent exudative disease is very important, as opposed to focusing on VA findings alone. The goal of treating patients who have exudative AMD lies in early diagnosis, not necessarily an objective decline in VA. In summary, any patient with a history of exudative AMD who develops subjective metamorphopsia while using Amsler grid or is found to have any cystoid macular edema or fluid with SD-OCT imaging should be promptly referred back to the retina specialist for care.
Keeping in mind that AMD can result in reduced central vision, we, as optometrists, need to consider our local low vision resources for these patients, when applicable. (To find a low-vision specialist, see http://bit.ly/2toLERH .)
So, how did I manage my 65-year-old AMD patient, and how is she doing today? First, I prescribed an AREDS2 nutritional supplement based on fundus findings and the size of drusen present, which was consistent with intermediate AMD.
I have followed her at three to four-month intervals based on the presence of the pigment epithelial detachment seen on OCT imaging, given that this lesion is known to be associated with an increased risk for progression to exudative disease.
I am happy to report that the patient has complied with the AREDS2 nutritional supplement and continues to have stable VA measured at 20/25 in each eye. In addition, she has no evidence of exudative disease to date.
EMPHASIZING OUR ROLE
Upon diagnosing a patient with non-exudative AMD, it is the responsibility of the eye care provider to have a conversation with him regarding the modifiable risk factors and the measures to reduce the risk factors, establish a follow-up protocol based on the risk for conversion to exudative AMD and refer the exudative disease patient to a retinal specialist. Keep in mind the primary care needs of the patient, and schedule your follow-up visits as indicated. The outlined steps enable us to help the AMD patient retain vision, emphasizing our value as a member of his health care team. OM