How to Track Vision Changes Day by Day

Sight problems are hard to describe from memory. By the time you sit in the exam chair, the blur has often cleared, and the details a clinician needs (which eye, how many minutes, what you were doing) have blurred with it. A written record fixes that. It turns "my eyes have been odd lately" into a dated sequence with duration, side and severity attached, which is the difference between a vague complaint and a description an ophthalmologist or neurologist can work with.

What to record each time vision shifts

Start with laterality, and test it properly: cover one eye, then the other. Vision that disappears when you cover one eye is monocular and points toward the eye or optic nerve; a problem present with either eye covered is binocular and suggests the pathway behind the chiasm. Record the type of change (blur, ghosting, double, dark or gray patch, shimmer, halos, floaters, flashes) and where in the field it sits: central, peripheral, upper or lower half, one side. Note onset speed in seconds, minutes or weeks, and total duration. Tag severity as mild (noticeable, reading still possible), moderate (interferes with work or driving) or severe (cannot read or navigate safely). Add whether blinking or lubricating drops clear it briefly, whether it followed a glucose swing, and any headache, eye pain, redness, nausea, numbness or speech difficulty around the same window.

Daily factors worth charting alongside vision

Log screen hours, sleep duration and quality, stress level, caffeine intake, sun and glare exposure, and every medication with its dose and timing. Blink rate drops sharply during focused screen work, so strain-related blur usually clusters on long screen days and eases on weekends. Migraine-associated visual change often tracks poor sleep, skipped meals, missed or extra caffeine, and bright light. Anticholinergics, antihistamines, steroids and some blood pressure drugs deserve a dose-timing note, because blur beginning within days of a dose change is worth raising. In Trace Health, lifestyle factors sit on the same timeline as your symptom entries, so after three or four weeks you can see whether episodes stack on screen-heavy days, follow nights under six hours, or ignore all of it and drift steadily worse, which points toward a lens or retinal cause instead.

Red flags and when to seek care

Treat as an emergency, same hour: sudden painless loss of vision in one eye, a curtain or shadow moving across the field, a shower of new floaters with flashes, double vision of abrupt onset, vision loss with weakness, facial droop or slurred speech, or a red painful eye with halos, headache and vomiting. Seek urgent same-day review for new temple pain, jaw ache on chewing or scalp tenderness in anyone over 50, and for pain on eye movement with dimmed or washed-out color, which can signal optic neuritis. A first-ever visual aura, even if it resolves fully in 30 minutes, should be assessed rather than assumed to be migraine. Gradual blur over months deserves a routine eye exam within weeks. Bring your record: clinicians will ask about laterality, speed of onset, duration, field position, pain, systemic symptoms and diabetes or blood pressure history.

Using Trace Health for visual episodes

One tap records an episode while it is happening, which matters for symptoms lasting 10 or 20 minutes that would otherwise be forgotten by evening. The three severity levels let you separate background strain from the episodes that stopped you driving, and reviewing them over months shows whether the severe entries are becoming more frequent. Companion symptoms such as headache, aura, light sensitivity, dizziness, eye pain, brain fog, numbness or nausea can be logged on the same day so their clustering is visible at a glance. The doctor-ready PDF gives an ophthalmologist or neurologist a dated episode list instead of recollection. Data stays on your iPhone by default with optional private iCloud sync, no account is required, and the app runs in nine languages if you prefer to log in your first language.

Frequently Asked Questions

How do I tell if a vision problem is in one eye or both?

Cover one eye with your palm, look at a fixed object, then swap. If the change vanishes when one eye is covered, it is monocular and the problem likely lies in that eye or its optic nerve. If it persists with either eye covered, it is binocular and involves the visual pathway in the brain, or both eyes independently. Do the test during the episode if it is safe to do so, and record the result immediately, because people often misremember which side was affected. Note the result in your log along with duration and any headache or pain.

Should I track visual aura if I already know I get migraines?

Yes. Even with an established diagnosis, the pattern is worth documenting: how long the shimmer expands (typically 5 to 30 minutes), whether it stays on the same side each time, whether headache follows or the aura occurs alone, and what preceded it. A change in the usual pattern, aura lasting over an hour, aura always affecting the same side, or aura accompanied by weakness or speech trouble are all things a clinician wants to hear about. Logging frequency also helps assess whether preventive treatment is worth discussing.

What should I bring to an eye appointment about intermittent blur?

Bring a dated list of episodes with duration, which eye, what the blur looked like and what you were doing beforehand. Add your current glasses or contact lens prescription date, a full medication list including eye drops and supplements, recent blood glucose or HbA1c values if you have diabetes, and blood pressure readings if you track them. Note whether blinking clears the blur briefly, whether it is worse in dim light or bright glare, and how many screen hours a typical day involves. A PDF summary covers most of this in one page.

Your health data stays on your iPhone.

No account. Private. No personal information is ever requested. Your health data stays on your iPhone by default. A backup option to your private iCloud is available. Trace Health never collects or sells your health data.

What people say

Rated 4.8 out of 5 from 50+ ratings on the App Store.

“The app is simple, fun, and life-changing for me. I chose it mainly so that my data is never shared, and because it’s the easiest to use. I used to write my symptoms down in a notebook; now I do it every day on the app to track how they change. Being able to also log my everyday activities to see their influence is very handy. I recommend it!” (Solex94, France)
“Out of all the symptom tracker apps, I found this to be the easiest and most straightforward. It “writes” to the health app, which is exactly what I wanted. All the others only “read” parts of the health app data, and didn’t truly write any data back. This helps me visualize my chronic symptoms soooo well.” (EB1700, United States)