Tag: PVD

What is the Vitreous?

The vitreous, also known as the vitreous humor, is a gel-like substance that fills the inside of the eye, occupying the space between the lens and the retina. It plays a crucial role in the development of the eye and in supporting the overall structure of the eye after we are born.

Composed mainly of water, the vitreous humor is a transparent, colorless gel that consists of a network of collagen fibers and various other molecules. It is synthesized during the early stages of development and persists throughout life. It is not renewed.

Function

The primary function of the gel is to provide mechanical support to the eyeball. It helps maintain the spherical shape of the eye, which is essential for proper focusing of light onto the retina. Additionally, the vitreous acts as a shock absorber, protecting the delicate structures within the eye from external forces or impact.

Moreover, this clear gel plays a role in the optical system of the eye. By virtue of its transparency, it transmits light, allowing it be focused on the retina. The retina converts light into electrical signals that are then transmitted to the brain, thus creating “vision.” The smooth, uniform consistency of the vitreous helps to ensure that light rays are not scattered or distorted as they travel through the eye.

Posterior Vitreous Detachment

While the vitreous is mostly a stable, gel-like substance, it can undergo changes that can impact vision. With age, the vitreous may gradually shrink and develop small pockets of fluid. This is known as a posterior vitreous detachment (PVD). This can lead to the formation of floaters, which are perceived as tiny specks or threads that seem to float across the field of vision. Although floaters are usually harmless, a sudden onset of numerous floaters or flashes of light may be a sign of a retinal tear. A retinal tear can cause a retinal detachment, which requires immediate medical attention. Sudden onset of floaters should always be checked by your eye doctor.

The vitreous is most important for normal development of the eye. Once we are born, it indirectly maintains various functions of the retina and the lens. Understanding the role of the vitreous can help appreciate its importance in maintaining healthy vision and identifying potential eye problems.

If you would like to schedule an appointment, please call us (877) 245.2020.

Nader Moinfar, M.D., M.P.H.
Retina Specialist
Orlando, FL

What is the Retina?

The retina is the light sensitive tissue that translates light into electrical signals for the brain. That’s how we see.

The retina is a highly specialized layer of tissue that lines the inside of the eye. As part of the central nervous system, it serves as a crucial component of the visual system. Its primary function is to convert light into electrical signals that can be translated to “vision” by our brain.

It consists of several layers of cells, each with a specific role in the process of vision. The outermost layer contains the photoreceptor cells, known as rods and cones. Rods are responsible for vision in low-light conditions and are highly sensitive to light, while cones are responsible for color vision and visual acuity in brighter light conditions. Cones are further classified into three types: red, green, and blue cones, allowing us to perceive a wide range of colors.

Converts Light to Electrical Signals

When light enters the eye, it passes through the cornea and lens, which help focus the light onto the retina. The rods and cones in the retina absorb the light and convert it into electrical signals. This process involves the activation of light-sensitive pigments within the photoreceptor cells, triggering a cascade of chemical reactions that generate electrical signals.

The electrical signals produced by the rods and cones are then processed by several layers of cells within the retina. Bipolar cells receive the signals from the photoreceptor cells and transmit them to ganglion cells, which are the final layer of cells in the retina. The ganglion cells collect the signals and their axons form the optic nerve, which carries the visual information from the retina to the brain.

Highly Specialized Cells Sharpen Vision

Within the retina, there are also other types of cells, such as horizontal cells and amacrine cells, which help refine and modulate the visual signals. These cells play a role in enhancing contrast, adjusting sensitivity to light, and facilitating communication between different parts of the retina.

The central region of the retina is known as the macula, which contains a high concentration of cones. At the center of the macula is a small depression called the fovea, where visual acuity is highest. The fovea contains a high density of cones, allowing for detailed and sharp central vision.

For us to see, all layers of the retina must be healthy, maintain normal blood supply and remain attached.

If you would like to schedule an appointment, please call us (877) 245.2020.

Nader Moinfar, M.D., M.P.H.
Retina Specialist
Orlando, FL

Jon Doe