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What Does Flashing Light on the Periphery of One Eye Indicate?

Eyes are organs of the visual system. They provide an organ with a vision which is the ability to process visual signals. Eyes operate on sets of various complex processes and nearly every organism in this world including microorganisms, have this feature in them. Eyes of microorganisms are much simpler than that of humans and their function is limited to sensing the surrounding lights. Bigger organisms have set off a complex optical system which collects light from the surrounding, regulates its intensity through the opening, and adjusts the focus through lenses and forms an image converts the image into electrical signals and sends it to the brain through the optic nerve. No wonder eyes are one the most delicate and complex organ of any organism.

Flashing Light on the Periphery of One Eye

What Does Flashing Light on the Periphery of One Eye Indicate?

Flashing lights and floaters usually indicate age-related liquefaction of the vitreous gel and its separation from the retina. Flashing lights signify acute vitreous gel detachment from the posterior retina. Most people see floaters or flashing light sometimes but a sudden onset of it can be something serious. In most of the cases, posterior vitreous detachment is associated with a retinal tear. Retinal tear, when left untreated, can lead to Retinal Detachment. People experience flashing lights and floaters at some point in their lives. Most people experience this in their teens and in some people it starts after their 50s. They are harmless most of the time it is just a sign of aging. But in some cases, it gives a warning sign of bleeding eye or diabetes and retinal eye.

Complex eyes can distinguish between shape and size. Many animals, like predators, have larger binocular vision to focus on any organism but preys like rabbit, deer, and horses have different eyes position to get a wide view of their surroundings. Human eyes have the ability to adapt to any environment because of its capabilities. They help to provide a three-dimensional, moving image that is normally colored in daylight. Although human eyes sometimes cannot capture the real color because of the presence of different waves like infrared and microwave, which are not visible from the naked eyes but human eyes can differentiate between 10 million colors and is capable of detecting a single photon. A photon is a light particle and is said to be equal to the size of wavelength. The wavelength of green light is 500 nm or two-thousandths of a millimeter.

Why Does Flashing Light in the Periphery of an Eye Occur?

The most general reason is the modifications in the vitreous which is a clear jelly-like substance which fills the back of the eye. As we age the solid jelly turns into a runnier like consistency as the attachment to the retina loses and the back end of the vitreous pulls off of the retina into the eye. The separation of the vitreous from the retina is called vitreous detachment or separation.

Consequences of Flashing Light in the Periphery of an Eye

To understand the cause of flashing light on the periphery of an eye, examination of the structure of a human eye is necessary.

The exterior segment is made up of ciliary muscle, cornea, iris, and lens. The cornea is transparent and more curved and acts as a link between the interior and exterior segment. The large exterior segment consists of vitreous humor, retina, choroid and outer shell called sclera.

The eyes are made up of three layers which enclose various anatomical structures. The outermost layer is known as a fibrous tunic and is composed of the cornea and sclera. The middle layer is known as a vascular tunic and consists of the choroid, ciliary muscles, and iris. The innermost layer is retina which acts like a screen on which inverted image is formed.

A dimension of the eyeballs typically differs from person to person by one or two millimeters. The eyeballs grow rapidly in infancy and by puberty; it attains its maximum size.

A typical adult eye has a diameter of about 24 millimeters but can vary according to ethnicities. Eyes have the thinnest blood vessel in the body and known was capillary nerves.

Functions of some basic structures are:-

Cornea- Cornea is the transparent front part of an eye that covers the major structures including iris, pupil, and the interior segment. The cornea contributes to the focusing power of an eye along with the ciliary muscle.

Ciliary muscle- It is a ring of smooth muscle in the middle (vascular) layer of the eye. The main function of ciliary muscle is to control the accommodation for viewing objects at a varying distance. It changes the sizes of the lens, not a pupil, to let in adequate light.

Iris- Iris is a thin circular structure in the eye and is responsible for controlling the diameter and size of the pupil and thus the amount of light reaching the retina. It is a diaphragm of the eyes and provides the structure to the pupil.

Optical lens- It is a transparent and biconvex structure in the eye that, along with cornea, helps to refract light to be focused on the retina. The lens, with the help of ciliary muscle, changes its size to adjust the focal length of the object, thus allowing a sharp real image that is screened on the retina.

Vitreous Body- The vitreous body is the clear gel that fills the shape between the lens and retina. Vitreous is very significant for the whole structure of the eye. It not only fills the void between the layers but also control the pressure inside the eyes hence preventing it from collapsing. Its viscosity is greater than water, giving it a gelatinous consistency.

Retina- The retina is the innermost layer of the eye. The optics of the eye creates a two-dimensional image of the visual world in the retina which translates the image into the electrical impulses to the brain to create a visual perception. There are two types of photoreceptors in the retina- Rods and Cones. Rods cannot distinguish colors, but are responsible for low-light monochrome or black and white vision; they work well in dark. Cones are responsible for color vision. They require brighter light than rods to function properly. Rods and Cones are connected through intermediate cells in the retina to nerve fiber of the optic nerve.

Optic Nerve- It is a bundle of more than one million nerves that carry the visual message. It connects retina to the brain. Damage to the optic nerves can cause permanent vision loss.

Cause of Flashing Light in the Periphery of an Eye

As mentioned above, the inside of an eye is filled with a gelatinous substance which is called vitreous humor. This problem is not a disease or disorder rather a sudden change in the eyes. If someone experiences sparkling then there is a chance of retinal detachment.

As someone age, the vitreous humor gradually loses its gelatinous nature and starts to shrink due to the lack of fluid. At some point, it doesn’t contain enough fluid to fill the eye and the inner layer pulls away from the retina. This action further tugs on the retina causing an arc-like flash of light in the periphery of vision. This pulling motion is called vitreous traction. Generally, vitreous tugging is harmless and normal at some point in life but it can occasionally create a tear in the retina and can lead to retinal detachment.
Other cause of flashing includes the blood leakage or hemorrhage, from a tiny vessel of the retina. Viral or fungal infection inside the eye can cause flashing. Although it is rare but ocular tumor can be a reason for slashing light on the periphery vision.

Symptoms of Flashing Light in the Periphery of an Eye

A retinal detachment can occur without any previous warnings. In some cases, the patient might experience a dark curtain or shadow effect across the vision. Detachment commonly occurs because of the age, with the retina becoming thinner and more brittle as one becomes old. Besides these, there are some other symptoms that can accompany, they are:

Blurred vision or distorted vision because of the fault in the retina, which disables retina to project a sharper image of the subject.

The occurrence of floaters, which are dark spots, around in one’s field of vision.

It is important to visit optometrist if anyone of the symptom occurs. The retina can be treated surgically if treated quickly, which will further prevent any vision loss. Failing in early treatment can be vision threatening and could result in permanent blindness. Torn or detached retinas must be promptly repaired by laser surgery or any other means.
The symptoms vary from person to person. The most common symptoms are as follows:

  • Blurred vision.
  • Holes or blurry spots in the vision.
  • Heat waves or moving lines.
  • Jagged lightning bolt shaped likes that seem to be moving or shimmering.
  • Kaleidoscope-like white or colored moving lights.
  • Gradually reduced peripheral vision.
  • A curtain-like shadow over the visual field.

Risks of Flashing Light in the Periphery of an Eye

Some of the common risks that lead to the increase of this eye disorder is as follows:

  • Increasing age is the main risk.
  • Conditions such as myopia, intraocular surgery and blunt trauma to the eyes are also some risks.
  • Previous retinal detachment in one eye.
  • The family history of retinal detachment.
  • Previous eye surgery such as cataract operations.
  • Previous eye diseases or disorders such as retinoschisis, uveitis or thinning of the peripheral retina.

Diagnosis and Treatment of Flashing Light in the Periphery of an Eye

The doctor might do the following tests, procedures or instruments to diagnose the flashes of light in the eye:

The doctor might do a retinal examination using a bright light and special lenses to examine the back of the eye as well as the retina.

The doctors might also use ultrasound imaging in case of bleeding from the eye when it is difficult to locate the retina.

Various treatments and surgeries are available in order to treat this eye disorder. The ophthalmologist might use any of the following treatment options according to the risks and benefits of it and also according to the condition of the patient.

The doctor might use laser surgery for a retinal tear in the patient. The surgeon directs a laser beam through the pupil into the eye. This creates a burn around the retinal tear which enables the retina to get fixed to its underlying tissue. The surgeon might also use freezing or cryopexy which causes a scar enabling the retina to get attached and secured to the eyewall.

Pneumatic Retinopexy is another possible procedure that the doctors might use in order to repair the retinal break. This process involves injecting gas or air into the eye which pushes the retina against the eyewall stopping the flows of fluid into space behind the retina. The doctor might also use Scleral Buckling which involves sewing of a silicone material over the affected area. This relieves some of the force caused by vitreous tugging on the retina. Vitrectomy can also be used in order to remove any tissue that causes tugging on the retina.

This is a very rare phenomenon whose symptoms can be connected to the optic nerve or brain and may need ophthalmic or neurological diagnosis and treatment. 65% of the patients are reported to be above 65 years of age. 90% of the cases have found to be none harmful while the remaining 10% can undergo serious problems which require immediate medical attention.

Prevention of Flashing Light in the Periphery of an Eye

Prevention is better than cure and whether one is suffering from these conditions or not, taking care of eyes is a must. You can preserve your eyes by following these three simple steps:

  • By eating a balanced diet and taking all the necessary nutrients that eyes and body need.
  • By quitting cigarettes and tobacco products, it is one of the greatest inhibitors of muscle generation which can cause early blindness.
  • Ultra-violet exposure is very harmful to human eyes, hence wearing a pair of polarized sunglasses is recommended by an ophthalmologist.


Taking good care of eyes is necessary for humans as they are blessing in disguise for mankind. Retinal detachment is curable at an early stage and should visit an optometrist as soon as they perceive these symptoms.


Team PainAssist
Team PainAssist
Written, Edited or Reviewed By: Team PainAssist, Pain Assist Inc. This article does not provide medical advice. See disclaimer
Last Modified On:February 28, 2022

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