Seeing green spots can be unsettling. These visual perceptions stem from various optical and neurological processes. Understanding their origins helps differentiate between benign occurrences and those warranting medical attention.
Common Reasons for Seeing Green Spots
A frequent cause of green spots is afterimages, which result from temporary fatigue of photoreceptor cells in the retina. Staring at a bright color, like red, makes its sensitive cone cells less responsive. When you look away, your visual system compensates, and you perceive the complementary color, often green. This is a normal physiological response.
Small specks or squiggly lines drifting across your vision are eye floaters. These are tiny clumps of collagen fibers or cells within the vitreous humor, the gel-like substance filling your eye. As people age, the vitreous can liquefy and shrink, causing these fibers to clump and cast shadows on the retina. While typically transparent, floaters can sometimes appear green.
Phosphenes are light sensations produced without actual light entering the eye. Mechanical stimulation of the retina, such as rubbing closed eyes, can trigger them. The pressure temporarily stimulates retinal cells, leading to perceptions of patterns or colored patches, sometimes green. Phosphenes can also occur from sneezing, coughing, or sudden changes in blood pressure.
Intense light or sudden shifts in illumination can temporarily cause visual artifacts. Prolonged exposure to bright screens may overstimulate photoreceptor cells, leading to temporary visual disturbances or afterimages that include green spots. This light sensitivity, known as photophobia, can also be a symptom of various eye conditions.
Other Potential Causes of Green Spots
Green spots can sometimes indicate more significant underlying conditions. Ocular migraines, or visual auras, are temporary visual disturbances that can manifest as shimmering lines, blind spots, or colors like green. These auras often precede a migraine headache but can also occur without one.
Retinal issues, such as a retinal detachment or tear, can lead to flashes of light (photopsias) or a sudden increase in floaters, which might be perceived as colored spots. These conditions happen when the vitreous gel pulls on the retina, potentially causing a tear or detaching the retina from its underlying support tissue. A sudden onset of new floaters or flashes warrants immediate medical evaluation as retinal detachment is a medical emergency.
Certain medications can also induce visual disturbances, including colored halos or tinted vision. For example, digitalis toxicity has been noted to cause photopsias, which are perceived flashes of light. In specific cases, a medication like cobimetinib, used in cancer treatment, has been linked to changes in the retina that can result in green spots.
While less common for specifically green spots, conditions affecting the optic nerve or intraocular pressure can impact vision. Ocular hypertension or glaucoma, which involve elevated pressure within the eye, can lead to visual field defects. Although green spots are not typical, these conditions can cause general visual changes that necessitate medical attention. In very rare instances, certain neurological conditions might also present with unusual visual symptoms, including colored perceptions.
When to Consult a Medical Professional
Seeking professional medical attention is important if you experience green spots, especially when certain symptoms accompany them. Immediate consultation is advised if green spots appear suddenly, particularly if they are new or significantly increase in frequency or intensity. This rapid change can signal a more urgent issue.
Specific accompanying symptoms also warrant concern:
- A partial or complete loss of vision
- Pain in the eye or a severe or unusual headache
- Nausea or vomiting
- Changes in the visual field, such as a curtain or shadow falling over vision
- Flashes of light (photopsia)
- A new, large, or sudden increase in the number of floaters
- Experiencing double vision
If green spots interfere with daily activities like driving or reading, or if you have pre-existing conditions such as diabetes or high blood pressure, vigilance and timely medical assessment are particularly important.
How Medical Professionals Diagnose Visual Disturbances
When evaluating visual disturbances, medical professionals begin by taking a detailed medical history, inquiring about the patient’s symptoms and overall health. This information provides important context for the visual complaints. A comprehensive eye examination follows, which typically includes checking visual acuity, assessing pupil response, and measuring intraocular pressure through tonometry.
A crucial part of the examination is a dilated fundus exam, where the eye care professional uses special drops to widen the pupils, allowing for a thorough inspection of the retina and optic nerve at the back of the eye. If initial findings suggest specific conditions, further imaging tests may be utilized. Optical coherence tomography (OCT) can provide detailed cross-sectional images of the retina, and fluorescein angiography, which involves injecting a dye, can highlight blood vessel abnormalities. In rare instances where a systemic or neurological cause is suspected, a patient might be referred to a neurologist or another specialist for further assessment.