To the Editor:
It is with more than just a bit of surprise that I have learned, from an article published in your August issue ("Back in the Spotlight Again: Managing Dry AMD" p. 28), that some of my colleagues still rely on the Amsler grid as a tool for self-monitoring the vision of dry AMD patients. While time-honored, there is little evidence that it can be of clinical usefulness in the early detection of wet AMD.
As correctly mentioned in the article, despite many efforts the value of the Amsler grid has not been clinically proven. For instance, Andrew M. Fine and colleagues pointed out that only 10 percent of wet AMD patients become aware of abnormal vision as a result of using the Amsler grid.1 Since then, a large number of additional studies were conducted to examine the true value of this "tool." Many ophthalmologists agree that the Amsler grid is not a reliable mean for monitoring vision,2,3 yet it is still advocated since it is felt that it's better than nothing, and with proper instruction it may in some cases be helpful.
Wet AMD is asymptomatic in early stages and, because it can progress quickly, by the time an Amsler grid abnormality is noted the lesion can be extensive.4,5 The lack of awareness for the developing disease is not only due to normal vision in the healthy eye, but primarily because of brain compensation mechanisms, which trick the patient to ignore details he is not accustomed to see. Hence, correct education—for example teaching the patient to test vision in one eye while covering the other eye—while necessary, does not promise success. In those rare cases where Amsler grid could make a difference, there is probably no need for it at all: With the same amount of education the patient could achieve similar results while observing poles, doors or window frames. Ignoring complex brain compensation mechanisms, however, is not a skill that patients can be taught to do. Were they to solely rely on the Amsler grid, most of our patients would suffer the consequences of late diagnosis.
Fortunately, psychophysical ways to bypass brain compensation mechanisms do exist. Pre-ferential hyperacuity perimetry (PHP), which was briefly mentioned in the article, is one such vision test. It has the advantage of being easily performed by unsupervised patients, and its clinical value has been repeatedly demonstrated.6-8
As was mentioned in the article, this technology has been adapted for home use where multiple tests per week are now possible. One of the key elements in this home device is its on-line connection to a centralized data monitoring center, which can alert the corresponding clinic in case of a detected deterioration of vision. Recently, I participated in a clinical study which followed a cohort of dry AMD patients who used this telemedicine system for a period of six months. The results of this study, which were presented in the last ASRS (2010) meeting, are very promising in terms of high frequency of usage, low rate of false positives and early detection of conversions to wet AMD. I therefore encourage my colleagues, even Amsler grid believers, to learn more about this alternative.
(The author has no financial interest in the PHP device.)
1. Fine AM, Elman MJ, Ebert JE, Prestia PA, Starr JS, Fine SL. Earliest symptoms caused by neovascular membranes in the macula. Arch Ophthalmol 1986; 104:513-4.
2. Crossland M, Rubin G. The Amsler chart: absence of evidence is not evidence of absence. Br J Ophthalmol 2007; 91:391-3.
3. Zaidi FH, Cheong-Leen R, Gair EJ, et al. The Amsler chart is of doubtful value in retinal screening for early laser therapy of subretinal membranes. The
4. Schuchard RA. Validity and interpretation of Amsler grid reports. Arch Ophthalmol 1993; 111:776-80.
5. Loewenstein A. The significance of early detection of age-related macular degeneration: Richard & Hinda Rosenthal Foundation lecture, The Macula Society 29th annual meeting. Retina 2007; 27:873-8.
6. Goldstein M, Loewenstein A, Barak A, et al. Results of a multicenter clinical trial to evaluate the preferential hyperacuity perimeter for detection of age-related macular degeneration. Retina 2005; 25:296-303.
7. Loewenstein A, Malach R, Goldstein M, et al. Replacing the Amsler grid: A new method for monitoring patients with age-related macular degeneration. Ophthalmology 2003; 110:966-70.
8. Loewenstein A, Ferencz JR, Lang Y, et al. Toward earlier detection of choroidal neovascularization secondary to age-related macular degeneration: Multicenter evaluation of a preferential hyperacuity perimeter designed as a home device. Retina 2010; 30:1058-64.
To the Editor:
Review's August article ("ASCRS Members Are Getting Aggressive" p. 70) discussing recent trends in keratorefractive and IOL surgeries was informative and well-timed. The mix of newer technologies combined with our wider body of experience clearly gives us the tools to bring safer and more effective treatment options to our patients. That backdrop combined with current economic realities provides a dynamic landscape where new boundaries are constantly being challenged.
My disappointment with the article stems from the lack of common sense and perspective that the author shares with his readers. Let's start with his discussion about clear lens exchanges on presbyopic patients. He seems to convey some level of confusion about why surgeons are doing fewer of them. Later in his article, he relates his surprise regarding consumer response to bad press surrounding the LVC.
It is evident this author-doctor has surely slept through Marketing 101. Let's review. A happy customer may tell a friend and an unhappy one will surely tell 10. Though none of us may choose to like this age-old fact, we must all live with it. Keratorefractive and premium lens surgeries have been commoditized. We enjoy the benefits and must also suffer the inevitable consequences.
With that out of the way, let's talk about the realities of LVC, premium IOLs and clear lens exchanges. As they are inherently elective and usually involve out-of-pocket expenditures, customers (a.k.a. "patients") set their satisfaction bar very high. So high, in fact, that many surgeons understandably begin to back off after being worn down by seemingly relentless dissatisfied patients. We all know that patients considering these procedures seem to relentlessly include the term "perfection" when discussing their options. Who can blame them, we all want perfect eyes, especially when it costs a bundle to get them. I am a 58-year-old presbyope and I wonder how much confidence I would have to opt for a clear lens exchange. I'm not there yet. And while we're at it, how many ophthalmologists who are now in their 50s have had clear lens exchanges performed on themselves? The room is quiet. Is there anyone out there?
I recall a simpler time, not too long ago, when postop patient disappointment with phacoemulsification and single-vision lens implantation was extremely rare. These days, I am tempted to take a quick test peek into my exam room before committing to walking in to do my postop check ups. Who knows, a shoe may come flying towards my head, and I fear that my reflexes may not be as good as our former president's.
These realities are all expressions of fundamental rules of marketing and human nature. Paying for something turns it into a commodity and, like it or not, expectations soar. To this point, I recall my recent dinner conversation with a highly acclaimed cataract surgeon, who had been a clinical investigator for a major premium IOL company. "Elliot, I don't understand," he said, … "During the study, everybody loved them and once they started paying for them, the complaints started rolling in."
Please understand, none of the cynicism that I convey should discount the elegance of this new generation of surgical refractive options. The options are amazing and are even more so when surgeons clearly understand and engage themselves in the sensitivities of their individual customers. The best surgeons use this understanding to optimize patient selection and outcomes. They meticulously individualize care, remembering that LVC and premium IOLs are not always the best option, remembering and adhering to the practices of delivering more than you promise and doing no harm. Those options will never burn you!
Elliot M. Kirstein, OD, FAAO
