Concussion recovery: what to expect week by week for vision

Concussion recovery is not a straight line. It's a zigzag with a generally upward trend — the upward part is real, but the zigzag is the part nobody warns you about. In the second or third week things may seem to be improving and then quietly slide back for a few days, and you may wonder whether you're making things worse or whether you've stopped recovering altogether. Vision is one of the systems most likely to be involved in those bumps, and one of the least talked about in standard concussion advice.

This post is a rough timeline of what tends to happen with vision after a mild traumatic brain injury — and a roadmap of when to wait, when to track, when to ask for help. The strongest caveat first: individual recovery varies enormously. Two people who hit their heads in the same way at the same time will not recover on the same schedule, and your clinical team's advice outranks anything written here. What this post is good for: a frame to hang your own observations on, and a sense of when the curve you're seeing is roughly in expected territory versus a sign to escalate.

What "concussion" means biologically

A concussion is a mild traumatic brain injury (mTBI) — a transient disturbance of brain function from a mechanical force to the head, without structural damage visible on a standard CT scan. A normal scan does not mean nothing happened; it means nothing happened at the resolution the scan can see. The injury is functional and metabolic rather than anatomical.

The current model of what's happening inside the brain in the first one to two weeks is the neurometabolic cascade, characterised in the landmark paper by Giza and Hovda. Mechanical force causes a brief, indiscriminate firing of neurons and release of excitatory neurotransmitters; the brain works overtime to restore ionic balance; glucose metabolism is elevated and then suppressed, cerebral blood flow falls below the increased demand, and the resulting energy-demand-versus-supply mismatch leaves the brain temporarily vulnerable. The precise length of that window is drawn largely from animal models — where the metabolic disturbance runs on the order of a week to ten days — and from clinical recovery timelines; together they point to roughly the first one to two weeks as the period of greatest vulnerability (Giza & Hovda, 2014).¹ During this window, neural systems that depend on tight metabolic regulation — including the visual processing pathways — are unusually sensitive to load.

Screen reading, fluorescent lights, busy visual scenes, and sustained focus all draw on the same energy budget the brain is trying to restore. This is why vision symptoms in the first week often look worse than the rest of the symptom picture — and why they tend to ease as the metabolic window closes, even before anything else changes.

Week 1: rest, observe, do not measure

The first week is not a tracking week. It's an observing week.

What tends to be present: light sensitivity, often markedly. Even ordinary indoor light can feel harsh; sunlight may feel impossible. Screens look weird — sometimes glaring, sometimes oddly hard to focus on. Reading is slower. Depth may feel slightly off in busier visual environments. A friend's face in a slightly dim room may take a beat longer to recognise than it should. Headaches with a visual component are common.

What is not happening, despite how it feels: your eyes have not become worse. The optics of the eye are typically fine; what's changed is the brain's ability to do the downstream work that turns retinal signal into the visual world. Most of these symptoms ease as the neurometabolic cascade resolves, even without any direct treatment of the eyes themselves.

What to do during week 1:

• Rest, in the modern sense, not the old sense. Older concussion advice prescribed a dark room and no stimulation; current consensus is that prolonged complete rest does not help and that gentle, sub-symptom-threshold activity is better. A randomized trial found that five days of strict rest gave no benefit over usual care and was linked to more prolonged symptoms (Thomas et al., 2015),² and the 2023 international consensus now recommends brief relative rest followed by a graded return to activity (Patricios et al., 2023).³ Follow the specific guidance the clinician who assessed you gave.
• Reduce screen time in proportion to how much symptoms flare with screens. Dimming the screen, lowering contrast, increasing font size, and using dark mode all help.
• Do not drive if your vision feels off or your light sensitivity makes oncoming headlights painful. When in doubt, don't.
• Do not take an at-home contrast sensitivity test this week. Your visual system isn't stable enough for the measurement to be meaningful. A reading taken in the first few days mostly captures how unwell you feel at the moment, not your underlying contrast sensitivity. Wait.

The honest expectation for week 1: things should not be getting noticeably worse day-over-day. Sustained worsening is a reason to contact your clinician, not to wait it out.

Weeks 2 to 3: a gradual baseline emerges

By the second or third week, the metabolic window is closing for most patients and a clearer picture of where you are starts to emerge. Light sensitivity often eases. Screen tolerance lengthens. Reading still takes more effort than before, but the wall is no longer at five minutes; it may be at twenty or thirty. Subjective vision is starting to stabilise enough to be measured.

This is a reasonable window to take a contrast sensitivity reading as a baseline, with a caveat: the baseline you take now is not the same thing as a pre-injury baseline. It's the start of your recovery curve — a reference point to compare future readings to.

How to set up the baseline well:

• Pick a session when you've been awake for at least an hour but not so long that fatigue is already in play. Mid-morning is often a good window.
• Sit in your usual lighting — the lighting you'll use for future sessions. Comfortable, glare-free, neither dark nor harsh.
• Use the same device you intend to use going forward. The calibration step at the start of our test anchors the geometry to your specific screen, but device-to-device comparisons are still noisier than same-device. Pick one and stick to it.
• Save the result and write a brief context line: date, light level, fatigue level (1–10), hours of screen time so far that day, headache or no.

In the published literature, contrast sensitivity can be reduced after a concussion even when standard visual acuity is normal — though studies disagree on exactly which part of the curve is most affected. One careful study found the contrast sensitivity function shifted toward higher spatial frequencies rather than settling into a single mid-range notch (Spiegel et al., 2016).⁴ The longer write-up on what the published literature does and doesn't say lives in the post-concussion vision changes post. For week 2 or 3: don't try to interpret absolute numbers. You're laying down the first dot in what will become a line.

Weeks 3 to 6: tracking the curve

This is the tracking phase. For most patients, the second-to-sixth-week window is where subjective symptoms and objective measurements move together — the curve tends to rise as the symptoms tend to ease.

A reasonable cadence is once or twice a week. More than that is overkill; less risks missing a meaningful shift. Keep the conditions of each session as similar as possible: same device, similar light, similar time of day, similar fatigue level. The more variance you can hold constant in the setup, the more of what's left will be real change in your visual processing.

What the trend tends to look like (the literature is clear on direction but extremely variable on rate — see the Greenwald, Kapoor and Singh 2012 review of visual sequelae through the first year post-injury):

• A gradual upward trend in the mid-frequency part of the curve.
• Day-to-day variability that can be larger than the underlying trend over short windows. Don't read individual sessions as verdicts. A drop on a single tired afternoon does not mean you've regressed; it means you were tired.
• Plateaus and small dips as part of the path, not departures from it. Recovery is not monotonic and was never going to be.

The journal entries alongside the readings are the part that makes the curve interpretable. If a dip lines up with a poor night of sleep, a long screen day, or the start of a cold, that's important context the number alone cannot supply. Look at the curve over four to six weeks of dots, not at any one dot.

If the curve is genuinely flat — no upward drift over several weeks, while symptoms also are not easing — that's a signal worth bringing to a clinician.

Weeks 6 to 12: where most people land

Through the second and third months, most mTBI patients see substantial recovery toward subjective baseline. The broad natural history of concussion is that the majority recover within days to a few months, while a meaningful minority — the "persistent post-concussion symptoms" group — continue to have measurable changes past that window; the international consensus statement describes this same trajectory (Patricios et al., 2023).³ Greenwald, Kapoor and Singh's review catalogues the range of vision-related impairments seen in the first year after TBI and stresses screening for them early (Greenwald, Kapoor & Singh, 2012),⁵ and Capó-Aponte and colleagues' military mTBI sample — in which roughly a third remained symptomatic at one year — characterises how visual dysfunction patterns evolve across acute, subacute, and chronic stages (Capó-Aponte et al., 2017).⁶

What that means practically:

• If you're at week 8 or 10, your subjective symptoms have largely resolved, and your CSF readings have trended back up, you are on the typical recovery curve. Taper the test cadence: weekly to fortnightly to monthly as things stabilise.
• If you're at week 8 or 10 and your subjective symptoms are still significantly limiting your day, and the curve has not been trending upward over the past month — that's the point to bring the trend to a neuro-optometric rehabilitation specialist, an optometrist with additional training in post-injury vision rehabilitation. (The post-concussion vision changes post covers what that kind of clinician does and how to find one; the Neuro-Optometric Rehabilitation Association directory is the most direct referral pathway.)

What CSF cannot tell you here: whether what you're experiencing is convergence insufficiency (trouble getting the two eyes to turn in together to focus on something near), accommodative dysfunction (trouble adjusting focus between near and far), or any of the oculomotor — eye-movement — problems that are actually the most common visual sequelae of mTBI in the published literature (Ciuffreda et al., 2007).⁷ Those need a clinical examination; they do not show up on an at-home CSF test. A reasonably normal-looking curve at week 10 with continuing symptoms is not "all in your head" — it means the slice of visual processing the test samples may have recovered while a different part hasn't.

Beyond 12 weeks: persistent symptoms

The literature consistently describes a meaningful minority of mTBI patients with persistent post-concussion symptoms — symptoms that continue past the typical recovery window. That group is real, and the right next step is specialist care: neuro-optometric rehabilitation for the visual-system component, vestibular therapy for the dizziness-and-balance component, and broader concussion clinics that can coordinate across the systems involved.

If you're past week 12 and the curve still isn't where it was before:

• Don't catastrophise. Persistent symptoms are not "permanent" symptoms. Recovery can continue over many months, sometimes well past a year, particularly with targeted rehabilitation.
• Do escalate the level of care. A standard optometric exam is excellent at what it covers and is not built to find the things that most often persist after concussion. The right specialist is a neuro-optometric rehabilitation provider; vestibular therapists and concussion clinics are the other two corners of the triangle.
• Keep tracking. Quarterly is reasonable past week 12 — the trend over months is the relevant timescale.

When to escalate sooner

Most concussion recovery is patient work — observing, resting, tracking, waiting. There are exceptions. Signs that warrant earlier contact with a clinician:

• Sudden worsening rather than gradual improvement. Recovery should not be reversing.
• Double vision, especially if it's new, persistent, or coming and going unpredictably.
• New visual phenomena — flashes, persistent floaters, a curtain or shadow in the visual field, distortion of straight lines.
• A vision change accompanied by a new severe headache, vomiting, confusion, weakness, or loss of consciousness.

These are not common after a typical mild concussion, but they are the categories where waiting is the wrong call. If any of these appear, contact your clinical team or seek urgent care, depending on severity. None of them are things an at-home test can resolve.

The slower-burning version: if your subjective symptoms still significantly limit your day past about week 12, your CSF curve hasn't shown the upward trend you'd expect, or both, that's the cue to schedule with a neuro-optometric specialist.

What CSF tracking can and cannot do here

A contrast sensitivity curve at home is one data point in a multi-input recovery process. It is good at: showing whether one slice of visual processing is improving over time on the same setup, and giving you something to bring to a clinician that isn't just memory. It is not: a diagnosis, a replacement for a neuro-optometric examination, or a verdict in any single session. The full account of what the measurement can and cannot do for post-concussion questions lives in the related post. The methodology specifics — calibration, adaptive procedure, contrast rendering — live on the methodology page. If you're tracking week-by-week recovery, the TBI tracking landing page is the front door we'd point you to; the conceptual background is in the primer.

A roadmap, not a verdict

Once you're past the first week and screens are tolerable, take a baseline. Track once or twice a week through the first month or two. Watch the trend, not the dots. Keep a short journal — light, fatigue, screen time, headache — alongside the curve so the dots are interpretable. By the time you sit down with a neuro-optometric specialist, you'll have something to put on the table that no single appointment could have generated on its own.

Your recovery is unlikely to look exactly like the version in this post. That's expected. The point of a timeline isn't to make your recovery match it — it's to give you enough scaffold that when yours doesn't match, you can tell whether the difference is normal variation or a signal worth raising.

Further reading (plain-language)

• National Library of Medicine, MedlinePlus — Traumatic Brain Injury. medlineplus.gov/traumaticbraininjury.html. A patient-facing overview of concussion and TBI — symptoms, recovery, and when to seek care.