Another really good question. First off, we want to emphasize a general point about clinical questions of this kind: specific therapy recommendations for a given individual in a given situation should come from one’s doctor and the ongoing treatment process. As an educational website, our job is to provide general information about chronotherapy to the public. The responses we provide are thus general, educational ones and should not be taken as clinical recommendations. With that caveat, let me share some thoughts about this type of situation.
First, baseline anxiety is something that I pay a great deal of attention to as a clinician when I am considering any antidepressant treatment. There is data that suggests that when depression is mixed with anxiety symptoms, the rate of antidepressant-induced manic response is heightened. Even when there’s no past history of manic symptoms, antidepressants can sometimes activate and reveal underlying bipolar dispositions that were not evident. Apart from the risk of treatment-induced mania, bright light therapy can cause or worsen ordinary (ie, not related to mania or bipolar disorder) anxiety as a side effect.
Second, I wasn’t clear about the nature of the diagnostic problem for which bright light therapy is being used here: were you using light therapy for seasonal anxiety, for depression, for depression mixed with anxiety? This would also have a bearing on how to manage your response to bright light therapy.
￼As a general rule, if someone that I am treating with bright light therapy experiences an increase in their anxiety, I would move to reduce and/or consider discontinuing the treatment. The good news is that bright light therapy can be quickly and incrementally adjusted in several ways: many light therapy lamps have a low and high lux option that allow for switching to a lower light intensity setting; the duration of exposure can be reduced; the distance from the light box can be increased; last, some studies suggest that light delivered later in the day, towards midday, causes less anxiety than early morning light. So there are several, easy tweaks that can be done to reduce bright light therapy-induced anxiety. The easy and rapid adjustability of treatments is a distinct characteristic and advantage of most chronotherapies.
You had the correct insight. The afternoon slump can occur with or without depression. If you measure the interval between the slump and the midpoint of nighttime sleep, they’re about 12 hours apart. (This is separate from the “post-prandial” slump some people experience after a heavy midday meal.) You don’t need to spend all day in “blinding bright light” to counteract the slump. The principle is to get to the light box as soon as you sense the onset of the slump, and not wait until it gets severe. This can nip the slump in the bud, even with 10,000 lux light exposure as short as 10 minutes. Some people will need longer, so you’ll need to experiment. There are days when the slump comes a bit earlier or later, so don’t set the light session by the clock. Rather, be attentive to the onset of the slump. This technique works for many people, but not for everyone. If it fails, and you have control of your work space, raising ambient light level in the afternoon to about 2000 lux – from ceiling or desk fixtures – including the light box – is another approach. Don’t overdo it, however, or you may experience jitteriness, headache, eyestrain, or sudden mood shifts that interfere with work.
The answer is: not that we know of. The symptoms you describe can certainly occur as short-term side effects, occurring during the use of a light box. But there is no evidence of cumulative, prolonged or delayed ocular and/or headache effects from ordinary bright light therapy usage. The combination of light sensitivity and light-aggravated headaches points in the possible direction of a migraine disorder. We suggest consulting a neurologist.
Never look directly into a 10,000 lux light box — it will be glaringly intense, and quite unnecessary. How you orient your head and eyes depends on what type light box you are using. CET’s recommended model, the Day-Light Classic Plus, was designed to direct light to your eyes from above the line of sight, thus illuminating the maximally sensitive lower portion of your retina. You receive adequate stimulation by concentrating on the work area below the screen — reading, eating, phoning, texting, working on your laptop, and so on. Wearing glasses is acceptable as long as they are not tinted. In other words, clear glass or plastic lenses are fine.
The difference between your spontaneous (late) wake-up at 9am and your goal, 530am, is large. The adjustment should be made more slowly. You should begin light therapy 30 minutes before your current wake-up time (in this case 830am), and stick with it until your wake-up has advanced by 30+ minutes. This may take several days, although sometimes it will happen in 1-2 days. At that point, shift light therapy another 30 min until you are stabilized at 8am. Continue this sequence until you reach 530 am, making sure you have adjusted comfortably at each step. It is possible that you will feel the full effect before reaching 530am, in which case you can maintain the later wake-up time (for example, 630am). Skipping a single day over the course of a week should not be seriously disruptive, but if you were routinely to skip whole weekends, your circadian clock will quickly shift later, and you may even have to back-track (for example, from 7am to 8am), if you have difficulty waking up on Monday morning, and proceed from the later hour.
Obviously, there is a risk of significantly slower adjustment if you skip days frequently. It would be helpful if you maintained a log (downloadable from Dropbox link http://ow.ly/VYgDW), which will help you review your rate of progress and identify possible disruptive influences. Bottom line: if the AutoMEQ advises waking up for light therapy more the one hour before your current wake-up time, you should approach the goal in small steps, waiting to adjust at each step.
When doctors advise patients to avoid sunlight, the risk factor is almost always ultraviolet (UV) radiation. As you can see from CET.org, an adequate light box should screen out UV, in which case there should be no UV risk. However, some light boxes screen out more UV than others, and boxes that use full-spectrum light bulbs present an additional challenge for adequate filtering. As a result, we can still see skin reddening and puffiness under filtered full-spectrum light, which is not good. CET recommends a light box with a polycarbonate diffusing screen and a lower color temperature (4000 Kelvin) than used in full spectrum boxes (5500 Kelvin and above). Unless your dermatologist wants you to avoid blue light as well as UV, this apparatus should suit your need.
No one has ever demonstrated that light therapy buffers against depression in non-depressed people, although that is conceivable. Not to throw cold water on your doctors’ strategy, but it is also possible they think using a light box would help maintain your good mood through its placebo effect. However, if difficulty awakening has been one of your problems even when you’re feeling well, the light box could be useful. And the light box can be used in conjunction with meds to enhance overall response–that is, to reduce the residual symptoms that meds fail to treat. If your historic problem is winter-seasonal, it makes sense to discontinue lights in early May, but if your historic problem is non-seasonal, whatever benefits you are finding with light could last year-round. Obvious strategy: if you begin to slump when you discontinue the lights, resume them!
There are certainly no definitive data to support these claims. Professional consensus remains that bright white fluorescent light boxes are the clinical standard. They have been thoroughly tested in multiple, independent clinical trials and their safety (barring UV and excessive blue light emission) has been documented in long-term studies. White light contains elements throughout the color spectrum, including green. The inclusion of a small amount of blue light in white light is thought to enhance circadian rhythm phase shifting, which may be an element of antidepressant action. Green light exposure needs to be greatly intensified in order to match the phase shifting efficacy of small amounts of blue. How the various spectral components contribute to the antidepressant effect is still unknown. Ergo: don’t jump on an isolated spectral component and expect it to perform equally or better (or to be safer) than white light
The combination of physical symptoms and fatigue makes this sound like chronic fatigue syndrome (CFS), which can indeed be debilitating–for up to several years–before it resolves. There is a host of treatment approaches, but no definitive curing agent. You should begin with a work-up by a CFS specialist (check www.cfids.org). Light therapy has been very helpful for people with CFS who have trouble waking up in the morning, who feel depressed, and become too tired to go to school or work. It may be very useful as an adjunctive treatment in CFS, but it is not a first-line intervention for the disorder.
The terms “full spectrum” and “broad spectrum” are not precise technical terms. Full spectrum–which is really just an advertising term–was developed as a type of broad spectrum lamp that emphasized short-wavelength emission, including UV. “UV-blocked full spectrum” is therefore a contradiction in terms. Furthermore, UV-blocking is incomplete using cheap plastic diffuser screens, leaving the opportunity for skin reddening and puffiness (even burning) in people with sensitive skin. These lamps may also cause retinal photosensitization when used in combination with various drugs.
Broad spectrum lamps include all fluorescent lamps with a white or whitish appearance. They are differentiated by “color temperature”, as measured in Kelvins. Full spectrum lamps have very high color temperatures (5500 Kelvin and above), which cause considerable visual glare at the high intensities used therapeutically. They are also electrically inefficient and more expensive than alternatives. Broad spectrum lamps of 3000-4000 Kelvin are much easier on the eyes and are equally effective therapeutically. We specifically recommend 4000 Kelvin lamps with complete UV filtering, based on the most recent clinical tests at Columbia University. For people whose doctors have recommended reduced blue exposure, to allay age-related macular degeneration, we recommend 3000 Kelvin lamps.