Most people who keep a headache log remember the sun. Fewer remember the ceiling. The fluorescent panels over a grocery aisle, the bright strip above a desk, the glossy floor of a pharmacy and the white walls of a waiting room all send light into your eyes for hours at a time. If you are heading to an examiner in the St. Louis metro this week, a short indoor light note can give that person more to work with than a general sense that the lights bothered you.
What to write down
Keep a simple sheet on paper or in your phone, and add one line each time you spend twenty minutes or more under bright indoor light. Write the date, the place, the kind of light if you know it, such as overhead fluorescent, LED panels or a bright screen mounted on a wall, and whether you could sit comfortably. Then note what happened next and how long it lasted. Plain words work best. Store, long aisle, buzzing lights, eyes watering, pressure behind the eyes by the checkout is far more useful than bad day.
Add a second column for shade. Sit near a window that is not directly in front of you, wear a hat indoors if that is allowed, or take a break in a dimmer room. If a change helped, write that down too. The goal is not to prove a cause. It is to show a pattern in your own days.
Places that often catch people out
Offices with overhead panels and white desks are a frequent source of complaints. Big-box stores, pharmacies and gyms often use strong light across wide floors. Schools and waiting rooms can be bright and echoing at the same time. Transitions can feel rough even when they last only a few seconds, such as walking from a dim parking garage stairwell into a brightly lit lobby. Note the changes as well as the brightness itself, since a sudden shift may matter as much as the level.
Keep the note in one place
Write the log in the same spot each day, or in one note on your phone, so nothing gets scattered across scraps of paper. Try to cover the days leading up to your visit, as far as you can manage it. Bring the printout or the screen with you. Put the most recent entries first, then add a short summary at the bottom: how many days brought indoor light trouble, which places came up most often, and whether a change in seating or breaks seemed to make a difference. Do not fill in numbers you did not actually record.
What the log can and cannot do
A light log does not diagnose anything. It cannot tell you whether a headache is tied to a particular ceiling, or whether your eyes need a new prescription. It can, however, give an examiner a clearer picture than memory alone. When you describe a week in order, with places and times, the conversation tends to stay focused. The examiner can then ask the right questions about your vision, sleep, neck and anything else that fits your situation.
Bring the log with you and say that you kept it on purpose. If you have a headache that comes on suddenly or feels severe, or if you notice changes in your vision or speech, weakness, confusion or trouble with balance, do not wait for a scheduled appointment. Contact emergency services or seek urgent care right away.
Before you go
Pick one or two places where indoor light has been hardest on you, and try a single change there, such as moving to a seat away from the strongest panel, during the week before your visit. Record what you tried and what happened. Do not start, stop or change any medicine based on a light log, and keep following whatever your own clinician has advised. A plain note, shared with a professional who can examine you, is one of the most practical things to bring to a first appointment this week.