Dark Circles Analysis: How Apps Score Under-Eye Darkness and Puffiness

Dark circles analysis in a skin app compares the color and brightness of the under-eye area with the cheek just below it, then tries to work out why it's darker: brown pigment, blue or purple show-through from blood vessels, a shadow from a hollow, or puffiness. Color points to pigment or vessels, while shape and shading point to hollows and bags. Overhead light can fake all of them.

This guide explains how each cause looks in a photo, what an under-eye score can and can't separate, why ceiling lights make circles look worse, and how to compare morning and evening scans so you're measuring your skin and not your bathroom. For what each type means and what helps, see our guide to the types of dark circles.

What does an app measure when it scores dark circles?

An under-eye score is usually a contrast measurement: how much darker, and in which color direction, the lower-lid skin is compared with nearby cheek skin. Clinical research works the same way. A 2021 study of 269 women photographed each face under a standard light source with a VISIA-CR system after 30 minutes of rest in a temperature-controlled room, measured color values with image software, and built a 0 to 4 visual scale, from no visible darkening to darker color across a larger area of both eyelids.

A phone app does a rougher version of this:

1. Find the region. Face landmarks outline the lower lid and the tear trough, the groove running from the inner corner of the eye.
2. Pick a reference. A patch of upper cheek serves as "your normal skin" for that photo.
3. Compare color. The app measures how much darker the lid is, and whether the difference leans brown or blue-purple.
4. Read shape and shading. Gradients, a bright rim above a dark band, or a bulge below the lash line suggest a hollow or a bag.
5. Report a score. Some apps give one number; better ones say which component drove it.

Using your own cheek as the reference helps cancel out skin tone and camera color. It doesn't cancel out light direction, which is the biggest source of error.

How do apps tell pigment, blood vessels and shadow apart?

Apps separate the causes mostly by hue and by whether the darkness behaves like color or like shadow. A dermatology review describes the clinical picture: the pigmented type shows an infraorbital brown hue, the vascular type a blue, pink or purple hue with or without puffiness, and the structural type is a shadow formed by the contours of the face. Many people have more than one at once.

Dermatologists have a simple test an app can't do: gently stretching the lower lid. Pigmented darkening retains its appearance with stretching, while a shadow improves or resolves entirely, and vascular darkening spreads out without much lightening. A camera sees only one moment, so it has to infer from color and shading, and it gets mixed cases wrong more often than pure ones.

This is also why some research leaves shadows out of color scales altogether. The 2021 scale study states that the structural type was excluded due to its structural shadows caused by skin contours. If a researcher with a VISIA camera won't score shadows by color, a phone app's shadow verdict deserves caution.

Can a photo measure puffiness and eye bags?

Only roughly. Puffiness is a shape, and a single front-facing photo flattens shape into shading, so the app infers a bag from a highlight on top and a shadow underneath. That works for obvious bags and fails for mild ones, and a smile or squint pushes the lower lid up and changes the reading.

Timing matters as much as anatomy. A review of under-eye darkness notes that eyelid swelling from fluid is often worse after a salty meal or in the morning, and that the fluid can look purplish. Fat-pad bags that come with age don't swing much through the day. Comparing morning and evening photos is the easiest way for you, or an app, to tell the two apart. Our guide to puffy eyes in the morning covers the common causes.

Sleep shows up too. In a study of 10 people photographed after normal sleep and after 31 hours awake, 40 raters judged the sleep-deprived faces to have more swollen eyes, darker circles and more hanging eyelids. A bad night can move your under-eye score without any change in your skin; more on that in what lack of sleep does to your skin.

Why does lighting from above make dark circles look worse?

Light from above makes dark circles look worse because the brow and the upper edge of the eye socket throw a shadow into the hollow under the eye, which reads as darkness. The review above says it plainly: overhead lighting can worsen the appearance of periorbital dark circles, while direct light may mask it. Bathroom ceiling lights, office panels and noon sun all do this.

Light angle changes how the whole face is judged. In a study of 153 standardized photos rated by 27 blinded raters, raising the light to 60 degrees above the face worsened nasolabial fold scores and lowered perceived attractiveness, while angles up to 30 degrees made no significant difference. The under-eye area, which sits in the deepest part of the face, is at least as sensitive.

The camera adds its own drift. A study of smartphone photos of skin-tone color swatches found that changing the camera angle shifted all three color channels, while changing distance mainly changed lightness. Tilt the phone up from below one day and down from above the next, and the measured color of the same skin changes.

How should I take under-eye photos for a fair score?

Face a window, hold the phone at eye level, and keep your face relaxed with eyes open and looking at the lens. The American Academy of Dermatology's patient photo guide recommends bright natural light from a window, no shadows or glare, and more than one picture of each view.

• Turn off ceiling lights so the window is the main source, falling on your face, not behind you.
• Keep the phone level with your eyes, about an arm's length away, never tilted up from below.
• Remove glasses, concealer and tinted eye cream.
• Keep a neutral face: no smile, no squint, eyebrows relaxed.
• Use the same spot, time and distance every time. Our skin selfie setup guide has a full checklist.

How do I track dark circles morning vs evening?

Take two scans on the same day, one within 30 minutes of waking and one in the early evening, in the same light, and repeat for a week. The differences between them tell you more than either score alone.

Log sleep hours, alcohol, salty dinners and allergy days next to each pair of photos. Cleveland Clinic lists aging, genetics, allergies, lack of sleep and dehydration among the common causes, and a short diary is the only way to see which of them moves your own numbers.

How can a selfie scan help with under-eye tracking?

A scan app gives you the same framing and a dated record, which is what morning-versus-evening comparisons need. Pori, our iPhone app, reads a selfie across a 468-point face mesh in about 10 seconds and returns an overall skin score with a breakdown that includes Pigmentation & Tone and Hydration & Moisture. It doesn't report a separate dark-circle score, so the most useful parts for under-eyes are before-and-after photo comparison, progress charts and the skin diary for sleep, water and stress. The first scan is free; Pro is $9.99 a week or $49.99 a year in the US as of October 2026.

An app is not a diagnosis. Cleveland Clinic advises seeing a provider for a dark circle or swelling under just one eye, or if the circles persist or come with marked swelling.