Seeing lights in your peripheral vision can be a disorienting experience, often prompting concern about eye health. These visual disturbances, while sometimes harmless, can also signal underlying conditions that require attention. Understanding the various reasons behind these light sensations is a first step toward addressing them, covering both common and more serious causes.
Describing Peripheral Light Sensations
Peripheral light sensations are perceptions of light originating within the eye or visual system, not from external sources. They are often described as flashes, streaks, shimmers, zigzags, or sparkles appearing in the side of your vision. Medically, these are referred to as photopsias.
These light sensations are distinct from “floaters,” which are shadowy specks, dots, or cobweb-like shapes that drift across your field of vision. Floaters are caused by tiny clumps within the vitreous, the clear gel that fills the eye, casting shadows on the retina. While flashes and floaters can occur together, especially with changes in the vitreous, they represent different visual phenomena.
Common Reasons for Peripheral Light Sensations
Many peripheral light sensations stem from benign and common causes. One frequent reason is ocular migraines, sometimes called “migraine with aura” or “visual migraines.” These can cause visual disturbances like zigzag lines, shimmering arcs, or flickering lights that typically affect both eyes and may last from five minutes to an hour, sometimes occurring without a headache.
Another common cause is Posterior Vitreous Detachment (PVD), related to the natural aging process of the eye. The vitreous, a gel-like substance filling the eye, naturally shrinks and liquefies with age, pulling away from the retina. As it detaches, it can tug on the retina, causing brief flashes of light, often described as lightning streaks. While PVD is a common, usually harmless part of aging, an eye examination is important to confirm it is not associated with a retinal tear.
Serious Medical Conditions and Peripheral Light Sensations
Some peripheral light sensations can indicate serious medical conditions requiring prompt attention. Retinal tears and retinal detachment are significant concerns, where the retina, the light-sensitive tissue at the back of the eye, is either torn or pulls away from its normal position. When the vitreous gel pulls too forcefully on the retina, it can create a tear, leading to flashes of light as the retina is stimulated. If fluid passes through this tear, it can cause the retina to detach, potentially leading to permanent vision loss if not treated quickly.
Vitreous hemorrhage, or bleeding into the vitreous gel, can also cause flashes of light, along with symptoms like new floaters, hazy vision, or a sudden decrease in visual clarity. This bleeding can occur from various causes, including a retinal tear, diabetic retinopathy, or eye trauma. In rare situations, neurological conditions like transient ischemic attacks (TIAs), often called “mini-strokes,” or occipital epilepsy can manifest with visual disturbances, including flashes of light. These conditions involve the central nervous system and warrant immediate medical assessment.
When to Consult a Doctor Immediately
Seek immediate medical attention if you experience certain changes alongside peripheral light sensations. A sudden increase in the number or intensity of flashes, particularly if accompanied by a sudden shower of new floaters, is a significant warning sign. The appearance of a shadow or “curtain” moving across your field of vision also indicates a retinal detachment.
Any sudden loss or blurring of vision, or a sensation of a “curtain” blocking part of your sight, especially with flashes, necessitates an emergency eye examination. Prompt evaluation by an eye care professional can differentiate between benign causes and conditions that could lead to permanent vision loss, allowing for timely intervention and preservation of sight.