Green is the easiest color to see varying shades of, and is part of why I have 3 separate "chapters" to compare eyes on. (Pain in my rear....)

So, back to things that eyes can do: so much of the expression is in the eyebrows.
Furrowed eyebrows (a scowl), for example, barely moves the lids. In fact, you could just sit there and place your finger over your eyes while you practice scowling like a very silly "author" just did. The only part of the lid that tightens in that is lower, towards the tear ducts, and that is faintly.

Squinting is a far more common movement to the eyelids. You squint from harsh sunlight. You also do it when enraged at a person you're about to light into. You do it when you don't trust what you're being told, eyes accusing people of their "crimes".

Another color that will get overused is olive. Chartreuse is slapped onto so many greens that I can't find 1 definitive color that it definitively is, but the liqueur comes in peridot and olive, with labels all over the spectrum. Khaki comes in tans, mostly, but there is an olive tone dark khaki. If there's any blue to the tone, moss works as well.

So, on to varaitions in olive.

1:

Almost tan green, but it is not seen as green because the skin tone next to it is too close on color for the brain to interpret it as anything other than "flesh tone". Belive me, if skin were that color, you'd look sick. This, too, is in the olive range. Dark khaki, specifically: highlights more tan like desert sand, and almond, darker end like gold. (As my art major spouse is obsessed with stating: the color gold is actually a green.) There's even a shift to the red (antique brass)a hair, right below the pupil and dark brown pupil rim.

Tigerskin Jasper

Ok, I don't think I've mentioned it before, but everyone's eye color shifts a hair because you're bouncing light through multiple layers. The slight red shift is from that aspect.

Why this gets labeled a green is that it is just barely a green tone and light browns are amber, a color more yellow and shiny (due to it being fat derived).

But I'd probably call these tan eyes, since they don't weigh heavily in any given category.

2:

Olive overall, but vibrant green (apple green to arylide yellow), hints of the color of Slimer (French lime), hints of canary yellow, with a definate red-tone brown inner (russet )and outer (rose ebony) rim. Chartreuse would work here.

Funny part is olive drab #3 is the same color as the vibrant green in this eye pic. Just not what we associate with it.

Unakite

3:

Olive. Oh, that outer rim (Charleston green)called the Limbus. It's a dark duck egg color. Flecks of olive green and olivine make up the main body of the iris. There is a faint shading of Peru to the right of the pupil.

Picture Jasper: if I am wrong about that faint tinge of orange (it's bound to happen some time), the color of this stone suits the orangish-tan streak of this eye. More chosen for contrast similarities.

4:

Almost grey. Not the limbus (dim gray with flecks of jet), but the layer next to it--the under color is grey (ash grey), while the over-and-light strands is a light olive (ecru). Inner rim is olive(stone gray).

In reality, this is a gray-and-yellow eye, up close. The problem is that those colors blended, is olive/green.

Prehnite

5:

An almost black green outer rim (pine tree), slightly yellow green middle (shifting between bistre brown, bitter lemon, bitter lime) to brown (middle red purple to bistre) inner rim.

Chrysoberyl

6:

Olive, overall. Highlighting strands are a touch yellow (desert), and underlayment is more blue (laurel green) with hints of taupe. Another near-black (black olive) limbus or root, and a more solid olive (antique bronze) towards the center.

Olive Quartz

7:

Green (olive) and brown(russet and dark brown), very like #5, but the green is true green (artichoke green) towards the root (olive drab #7) and lime (citron) towards the brown.

Marsden Flower Jade

8:

Same general tone as the olives but too blue and not enough brown to be labeled olive. Reminds me of duck egg or mint, overall: feldgrau green low (barely seen), flecks of aero blue high, opal and morning sky midtones with a Charleston green root works.

Green and White Feldspar

9:

Contact. They are hardest to hide in green (again, because we see the most shades of this color). The inner ring is grullo, then macaroni and cheese, then morning blue, and the outer rim averages out to a raisin black.

Brown and Green Chrysanthemum Stone

10:

Looks similar to the contact, but this is the real thing. Almost hunter green (kombu green) limbus, almost mint green and light brown iris (middle yellow red and wood brown), dark brown inner ring. Having this distinct of color variation is called heterochromia iridium or heterochromia iridis.

Green agate

11:

Olive, darker lighting tricks the eye into thinking the eyes may be blue. Not like there's no fat folding in white-dominant ancestry, it just tends to look more like this than II:8. The upper eyelid is heavily obscured because of the displacement of the top half the lid. This is what my eyes are starting to do, which means the highlights I used to notice are fading.

So this eye color is shaped in shades of gray because of the lack of light.

The midtones are cadet gray (blue) and ash gray (green), lows are xanadu (green) and Davy's gray (neutral). Inner rim is cinereous (brown), while the outer rim is jet.

Dead Camel Jasper

12:

High contrast olive. Deep flecks of midnight green. The one brown-rimmed (sand dune) dark spot (bottom left of pupil) is an eye freckle. This is what a frost (mostly misty moss, sage inner rim, highlight Navajo white, some saffron, sand) over green looks like olive from a distance. Limbus is nickel.

Moss Agate

13:

This is likely contacts, Loking much like #9 (possibly the same contact under different lighting, or a different color of the same pattern). This has too much repeatability or uniformity. Real eye color, even in the monochromatics, is variable. But from the root in: Eerie black, gray-green, marengo, magic mint, honeydew, straw, sunray.

Olive Citrine

14:

Jewel tone olive. In color order: honeydew, tea green, celedon, fern, forest green, olive, olive drab camouflage, olive drab #7, black olive.

Silver Leaf Jasper

Reminds me of trees and grass. This is the first time that it appears that the stroma is the darker layer of the eye. This is because it is reflecting the window's image.

So, practical application:

She looked out the window, eyes heavy with concern. This didn't stop the joy of the day from reflecting in her eyes. Wisps of honeydew and celadon refracted from mirroring the grassy groundcover that had not quite wilted in the midsummer heat. Of course, it was expected that her green eyes would dance with such colors, but they were never quite this luminous.

It also has a heavy root (dark and thick). The eyelid folds over the eye so heavily supposedly because of fatty tissue. While that can happen to anyone, it's more common in those who have Asian ancestry. Contrast with #11, and see how a heavy brow partially does this same thing.

15:

Murky, not quite olive (feldgrau evenly between both rims). In this case the makeup is doing what it is supposed to do. This would be a straight-up olive with a brown inner ring, but the teal eyeliner is shifting the color of the eyes a bit. Minor flecks of celedon. Inner rim is olive drab #7 and outer rim is just shy of olive drab camouflage.

Thunderstruck Gladstone

16:

Dark skin with olive. The mind plays tricks on you. It wants to interpret this as a night picture of pale skin and that olive as a light frosted green. The color is marbled, though, with deep pockets (xanadu) nearly matching the inner rim (ebony). The limbus is Jet and the highlight is ash gray.

Light Green Moissanite

17:

Dark skin with light green (med low feldgrau, olivine randomized waveform). Pupillary rim is olive drab camouflage, while the root is gunmetal. This has a clear iris freckle or 2. Appears to be mint to olive.

Prasiolite

18:

Like #I:4, and #II:5, this eye has a ripples in a pond look to its luminosity. It is an olive green overall (antique bronze), though with yellow highs (jasmine to jonquil) as well as lighter green (June bud). There's flashes of NDHU green. Inner ring and upper eye looks to be a light brown (ranging from Peru to taupe), and the outer rim is dark olive (raisin black with bursts of antique bronze breaking up the color).

Idocrase

19:

I have some extra room for an edit, although I have a full chapter later for full fantasy derived eyes. (This reminds me of 30StM's From Yesterday.) Yes, the Earth is on #18. Cute.

The 1st ocean is a range between black, space cadet, and navy blue while the 2nd is Charleston green, royal blue, and ultramarine.
The 1st forest is hunter green to Charleston green while the 2nd forest is tropical rainforest, and UP forest green.
In both, the yellow high is unmellow yellow, but the orange is seperate. 1st is goldenrod to butterscotch, with a brown of wenge while second is xanthous to atomic tangerine with a brown of cinerous.

1st: Azurite and Malachite
2nd: Stitchite in Serpentine