Eye , Eye color,and How To Draw Eyes ? العيون و الوانها وكيفيه رسمها

Eyes are organs that detect light, and convert it to electro-chemical impulses in neurons.In higher organisms the eye is a complex optical system which collects light from the surrounding environment; regulates its intensity through a diaphragm; focuses it through an adjustable assembly of lenses to form an image; converts this image into a set of electrical signals; and transmits these signals to the brain, through complex neural pathways that connect the eye, via the optic nerve, to the visual cortex and other areas of the brain.The simplest "eyes", such as those in microorganisms, do nothing but detect whether the surroundings are light or dark, which is sufficient for the entrainment of circadian rhythms.
From more complex eyes, retinal photosensitive ganglion cells send signals along the retinohypothalamic tract to the suprachiasmatic nuclei to effect circadian adjustment.

Types of eyes
There are ten different eye layouts .Eye types can be categorized into "simple eyes", with one concave photoreceptive surface, and "compound eyes", which comprise a number of individual lenses laid out on a convex surface. Note that "simple" does not imply a reduced level of complexity or acuity.
It will be so long and complicated to write the types .

Eye color 
Eye color is a polygenic phenotypic character and is determined by the amount and type of pigments in the eye's iris.Humans and other animals have many phenotypic variations in eye color, as blue, brown, gray, green, and others.
The genetics of eye color are complicated, and color is determined by multiple genes. 
Three main elements within the iris contribute to its color: the melanin content of the iris pigment epithelium, the melanin content within the iris stroma, and the cellular density of the iris stroma.In eyes of all colors, the iris pigment epithelium contains the black pigment, eumelanin.
Eye colors can range from the most common color, brown, to the least common, green.Eye colors range from the darkest shades of brown to the lightest tints of blue .

Changes in eye color 
In all populations, children are most commonly born with unpigmented eyes.
Changes (lightening or darkening) of eye colors during puberty, early childhood, pregnancy, and sometimes after serious trauma (like heterochromia) do represent cause for plausible argument to state that some eyes can or do change, based on chemical reactions and hormonal changes within the body.

العين، عضو الإبصار 

العين هي شبكة كروية وقطر عين الإنسان البالغ يصل إلى 2.5 سم تقع العين في مقدمة الجمجمة محمية داخل محجر العظمي، والعين قادرة على التحرك داخل المحجر بصورة حرة بمساعدة جهاز معقد من العضلات الطولية والعرضية المحيطة بالعين داخل المحجر.و في منطقة الحاجبين يبرز عظم الجمجمة لحماية العين من الاصابات الخارجية ومعروف ان للعين 6 عضلات خاصة تحركها 

العين هي عضو يلتقط الضوء الذي تعكسه الأشياء، وهي المسؤولة عن الإبصار. وهي عبارة عن مستقبل حسي يتفاعل مع الضوء الصادر من الشيء المريء أو المنعكس منه ويقوم عضو(الشبكية) في العين بتحويل هدا الضوء لسيالة عصبية التي تنقل عبر الاعصاب ومن تم نحو الباحة البصرية الموجودة في الدماغ 

 Now our design today is the eye.

That is a combination of photoshop and illustrator design .Mainly using the Transform and Free Transform Tools
FOR HOW TO DESIGN PLEASE read more .

The video.











 All the curves are easy to draw with Illustrator, and the eye brow is found in illustrator Symbols . 

• Open a new illustrator document and draw an arc with the Arc Tool . That arc you can use for the eyelashes  and eyelids .
•  Save the Illustrator artwork in pdf so you can open it in Photoshop .
• Open two documents in Photoshop window and drag the arc from the Illustrator window to the eye document with the Free Transform Tool scale it and adjust its direction to use as an eye brow and eyelid ,and also the eyelashes 
•  For the eyebrow use Warp [Edit - Transform -Warp] 
• For the Iris draw acircle and fill it with Radial Gradient with Gradient Tool .
• For the background I prefer the gradient color .
•  Save your work . 

Thanks
Manal  Raafat