What is Macula Lutea?
The macula lutea, also known as the macula, refers to the small area in the back of the eye that is responsible for central vision. The macula is located in the retina, the back of the eye. The macula can be divided into subregions which include the fovea and foveola. The macula is responsible for sharp and detailed central vision, as well as color vision. If the macula gets damaged, such as in diseases like macular degeneration, the color vision and central vision may be affected.
Key Takeaways
- The macula lutea is the central part of the retina, which is the back layer of the eye.
- The macula is responsible for clear and detailed central vision, such as when we look directly at an object. It also allows us to see colors.
- Diseases such as diabetic retinopathy, macular degeneration, and Stargardt’s can damage the macula and cause loss of central vision.
Understanding Macula Lutea
THe macula or macula lutea is an oval-shaped pigmented area located in the center of the retina in the human eye. It is the area of the eye that provides central vision. The macula lutea’s function is to sense light. It has over 200 million neurons that send information to the brain. The macula is the most important structure for seeing clearly. In Latin, the term macula refers to ‘spot’, while lutea means ‘yellow’. The macula lutea essentially looks like a “yellow spot” in the back of the eye.
The yellow color of the macula lutea is due to the presence of lutein and zeaxanthin pigments. Lutein and zeaxanthin are antioxidants that protect the retinal cells from damage. Lutein and zeaxanthin are derived from vitamin A and protect the macula from UV light damage. When you go to the grocery store and buy eye vitamins, they probably have lutein and zeaxanthin in them. People with a family history of macular degeneration, or people with moderate to severe macular degeneration, are recommended to take lutein and zeaxanthin supplements.
Structure Of Macula Lutea
The size of the macula lutea is very small, approximately 5 millimeters (less than ¼ inch) wide. However, despite its small size, the macula is responsible for most of the central vision and color vision. The macula is classified into six regions. From outer to inner, these regions are : perifovea, parafovea, fovea, foveal avascular zone, foveola, and umbo. The appearance of these layers blend together when looking at the macula, so it’s hard to tell them apart. The most important region of the macula is the center of the macula, the part called the fovea. The fovea is specialized for high visual acuity and color vision. It contains only cone photoreceptors, and no rod photoreceptors. The cone photoreceptors are highly specialized in seeing fine details. Cones also allow us to see all of the colors of the rainbow, and without them the world would look black and white. The fovea is only 0.35 millimeters wide, but it plays an important role in the macula’s function.
The Function Of Macula Lutea
The macula lutea has the highest concentration of cone photoreceptors inside of the retina. Photoreceptors are specialized cells that detect light and send signals to the brain, converting them into images. Cone photoreceptors are responsible for sharp vision and color differentiation, and they allow us to see clearly in well-lit situations. On the other hand, rod photoreceptors have poor vision but allow us to see in the dark. The fovea, the center of the macula lutea, has only cones and no rods. The high concentration of cones in the fovea allows for excellent central vision.
Clinical Significance of Macula Lutea
If any disease affects the macula lutea eye, it will ultimately affect the central vision. Even lesions that are small in size can affect the macula and cause significant problems in the macula lutea’s function. Symptoms of a damaged macula may include:
- Poor central vision:
The center of the vision may appear blurry or dark. This may result in trouble seeing faces and other objects. Some people may see a black spot in the center of the vision. - Image distortion:
Straight lines may appear to be wavy. A tool called an Amsler grid can be downloaded online or obtained from an eye doctor to monitor for any distorted areas of vision. - Color reduction:
Colors may look less vivid or bright.
Conditions that damage the macula lutea and cause vision loss include:
- Age-related Macular Degeneration (AMD):
This condition affects people aged 50 years or older. It is a buildup of waste products in the retina. The waste buildup damages the cone photoreceptors, so the vision will become progressively blurry over time. The vision loss caused by macular degeneration is irreversible. In severe cases, people with macular degeneration may need to be treated with medicine injections into the eye. - Macular Hole:
A hole in the macula can cause a central blind spot or blurry central vision. It can be treated with surgery to close the hole and improve vision. - Retinal Detachment:
If retinal detachment occurs in the macula lutea, central vision will likely be affected. Surgery should be done as soon as possible after onset of symptoms. - Diabetic Macular Edema:
Poorly controlled diabetes can cause swelling of the macula lutea. Diabetes can make the blood vessels in the back of the eye leak fluid, which makes the macula swell. - Epiretinal Membrane:
Cells build up on top of the macula, which pulls on the macula and wrinkles the macular tissue. This wrinkling of the macula can cause vision to appear distorted and wavy. - Stargardt’s Disease:
This rare genetic condition causes progressive central vision loss that starts in childhood.
