Why Are Brown Eyes Most Common? - American Academy of Ophthalmology
2017年4月7日 · People with brown eyes have a lower incidence of eye cancer, macular degeneration and diabetic retinopathy. Ophthalmologists are not exactly sure why, but believe that melanin pigment may give brown eyes more protection.
What to Know About Having Brown Eyes - Vision Center
2024年9月24日 · Light Brown Eyes: Light brown eyes are sometimes called golden or honey-brown because they have warm tones ranging from yellow and amber to light shades of brown. Dark Brown Eyes: Dark brown eyes are the deepest, richest shade of brown.
Eye color - Wikipedia
A brown iris. Almost all mammals have brown or darkly-pigmented irises. [27] In humans, brown is by far the most common eye color, with approximately 79% of people in the world having it. [28]
Differentiating Iris Pigmented Lesions: A Primer
2020年2月1日 · When a patient walks in with one green iris and one brown iris, or one light brown and one dark brown, the darker iris could have melanocytosis, which is a congenital condition in which the uvea gets too much pigmentation, putting …
Iris (anatomy) - Wikipedia
The iris (brown coloured portion of the eye) controls the size of the pupil by contracting the sphincter pupillae and dilator pupillae muscles. The sphincter pupillae is the opposing muscle of the dilator pupillae. The pupil's diameter, and thus the inner border of the iris, changes size when constricting or dilating.
Brown eyes - Facts about brown eye color - All About Vision
2019年2月27日 · In the United States, an estimated 41% of the population has brown eyes — including dark brown eyes, light brown eyes and honey brown eyes. If you include hazel eyes (sometimes called hazel brown eyes), the prevalence is even higher. But a high prevalence of brown eye color doesn't mean all brown eyes look the same.
Brown Eyes: Facts About Their Color and Rarity | Warby Parker
2024年9月10日 · Brown eyes appear brown because the front layer of the iris (the stroma) is rich with melanin, too. Lighter eyes—like blue eyes, for instance—have little or no melanin in the stroma. But blue eyes don’t contain blue pigment. Rather, the lack of melanin in the stroma allows light coming into the eye to scatter and reflect back out.
Eye Colors: Hazel, Green, Amber, Blue, Grey & Brown - Cleveland Clinic
2024年3月11日 · When you have a lot of melanin in both layers of your irises — front and back — you have brown eyes. (Experts sometimes spell the plural of iris as “irides.”) People with hazel or green eyes have less melanin in the front layer of their irises than people with brown eyes.
Iris of the Eye: Anatomy, Functions & Associated Conditions
2024年10月31日 · Sufficient amounts of melanin will make your iris brown. A reduced amount of melanin allows light to pass through and get scattered by collagen fibers, resulting in a bluer color. Depending on the extent of pigmentation, the color can range from light blue to dark brown. Common eye colors include blue, green, hazel, or brown.
Iris color and associated pathological ocular complications: a …
2014年5月25日 · In the Blue Mountain Eye study of whites aged over 49y, baseline cross-sectional analysis revealed that eyes with dark brown irises were more likely to have nuclear [odds ratio (OR), 1.59; 95% confidence interval (CI), 1.03-2.28 ] or posterior subcapsular cataract (OR=2.50; 95% CI: 1.57-3.98) than eyes with lighter-colored irises [14].