The retina is a thin, membranous tissue, located in the innermost layer of eyeball, and it can also be called the‘film’ in the camera.
Its function is to detect the light entering from outside and transmit the information to the brain via the optic nerve.

Retina is a thin membrane, approximately 0.1〜0.5mm, composed of 10 layers. It consists neural retina, which has 9 layers, and a single pigment epithelium layer.
The following cells in each layers of optic nerves are functioning：

１.Optic cells layer

• ◼︎ To detect the existence the light cells
• ◼︎ Rod cell: responsible for vision in the dark places
• ◼︎ Cone cell:responsible for the colour vision and light places

2.Bipolar cell・horizontal cell・amacrine cell

• ◼︎ To organize the information which the optic cell received, and transmit to the optic nerve.

3.optic ganglion cell

• ◼︎ To transmit the processed information to the optic nerve.

The main role of retina is to ‘detect the light and transform into the electronic signal, and transmit to the brain’
If it’s like a camera, the lens (corneal and crystal lenses) collect the light, and the film (retina) record the image.

It works like following：

１.To detect the light

• ◼︎ The optic cells ( rod cells・cone cell) in retina to receive the light

  • ⚫︎ Rod cell: active in dark places( to feel the light and dark contrast)
  • ⚫︎ Cone cell: active in the light places( to recognize the color and small shapes)

2.To convert the light into the electric signal

• ◼︎ The optic nerve can receive the light and transform into the nerve signal.
• ◼︎ This signal will be organized via bipolar・horizontal cell・amacrine cell

3.To transmit to the brain via optic nerve

• ◼︎ Finally the optic nerve ganglion will organize the signal and transmit to the occipital lobe (visual cortex).
• ◼︎ The brain will process the information, which is what we said ‘ see it’.

The representative disease of retina are as follows

• ◼︎ Retinal detachment: the condition which the retina nerve detach from the retinal pigments
• ◼︎ Age-related macular degeneration: low central vision, more common in older adults
• ◼︎ Diabetes retinopathy: the damage to blood vessels caused by diabetes, leading to decreased vision.
• ◼︎ Retinal pigmentosa: genetically inherited progressed vision impairment

Because the eyes are very delicate, and any disease affecting them can directly impact vision, regular eye examinations are essential.