It may involve addressing any underlying health conditions, adjusting medications, or in some cases, surgical intervention. It is important to consult with a healthcare professional for proper diagnosis and treatment. Tonic pupil, or Adie pupil, is a well-known cause of anisocoria. The affected pupil demonstrates a response with poor constriction to light but significantly better to accommodation; this is referred to as light near dissociation. The tonic pupil is often benign but may eventually become miotic. Pupils get larger (dilate) in dim light and smaller (constrict) in bright light.
This pupil will, at most, minimally constrict with light and, much of the time, will not react at all due to paralysis. Pilocarpine will not be effective in causing this pupil to constrict. Cycloplegic eye drops include cyclopentolate, atropine, and tropicamide.
When is anisocoria normal?
Depending on the specific chemical, this can take hours or days. There are many medications or chemicals that can cause the pupil to dilate or constrict. While some of these medications are intentionally used in the eye, sometimes these medications or chemicals are accidentally rubbed into the eye from your skin, usually by your finger. By utilizing these diagnostic tools, healthcare providers can gain a clearer understanding of your condition and develop an appropriate treatment plan. Conversely, in dim lighting, your pupils dilate to allow more light to enter, enhancing your ability to see in low-light situations.
- While measuring the pupils, the patient should focus on a distant object.
- Anisocoria, or unequal pupil sizes, can be a curious feature of the human eye—sometimes harmless, sometimes a sign of something more serious.
- Brain disorders that can affect these pathways include strokes, brain hemorrhage (spontaneous or due to head injury), and, less commonly, certain tumors or infections.
Enhancing Healthcare Team Outcomes
The content herein is provided for informational purposes and does not replace the need to apply professional clinical judgement when diagnosing or treating any medical condition. A licensed medical practitioner should be consulted for diagnosis and treatment of any and all medical conditions. However, if anisocoria is due to a medical condition, addressing that condition is the priority. Schedule an appointment with an eye doctor near you to examine your pupils and discuss the best treatment options. If you notice that your pupils are not equal in size, schedule an eye exam as soon as possible to rule out any serious conditions. If these symptoms come on suddenly, seek immediate medical attention.
Physiologic Anisocoria (unequal pupils)
Doctors first ask questions about the person’s symptoms and medical history, including questions about smoking. What they find during the history and physical examination often suggests a cause of the unequal pupils (see table Some Causes and Features of Unequal Pupils) and the tests that may need to be done. Physiologic anisocoria is pupils that are naturally different in size. About 20% of people have this lifelong condition, which is considered a normal variation.
Also, the underlying disorder sometimes causes other symptoms such as eye pain and redness, loss of vision, drooping eyelid, double vision, or headache. These more noticeable symptoms, rather than the unequal pupils, are often the reason people seek medical care. Nervous system disorders that cause unequal pupils are those that affect the third cranial nerve or certain parts of the sympathetic or parasympathetic nervous system (the autonomic nervous system). These pathways carry nerve impulses to the pupil and to the muscles that control the eye and eyelid. Thus, people with nervous system disorders that affect the pupil often also have a drooping eyelid, double vision, and/or visibly misaligned eyes.
TNP is potentially life-threatening if caused by an aneurysm, and Horner syndrome can indicate carotid dissection, among many other possibilities. A comprehensive radiological workup may be required in these cases. Anisocoria itself is unlikely to cause significant complications, although some do exist. A larger pupil may cause light sensitivity and visual aberrations. A smaller pupil may cause worsened visualization through a cataract, difficulty viewing the fundus during the posterior exam, or difficulty in cataract surgery. The main complication of anisocoria is not the difference in pupil size but the complications of the underlying condition itself.
Looking at an old picture of the patient can help show that the anisocoria may be chronic. Next, a thorough history of the medications the patient takes needs to be made, especially eye drops that have been put in the patient’s eye. A history of a recent visit to an eye doctor is also very helpful since the anisocoria could be caused by eye drops given during the visit. A history of eye trauma and eye surgery must also be elicited from the patient, as these can be the cause of anisocoria.
One common reason for unequal pupils is a difference in the way each eye responds to light. This can occur due to conditions affecting the muscles or nerves that control pupil size. Once a thorough history has been taken, the abnormal pupil needs to be identified. To do this, both pupil sizes should be measured with the room lights on brightly and then again with the room lights dim. Having the room lights completely off may not be practical since the pupils need to be visible for measurement.
Different sized pupils could indicate a serious health issue requiring urgent medical care.
Diagnosis of the cause of unequal pupils involves a comprehensive physical examination, including an eye examination and a neurological examination. This can be a harmless physical feature or a sign of an eye or brain problem. Babies with anisocoria should have an initial physical examination to determine whether a serious cause needs to be addressed. The pupils of the eyes normally constrict (get smaller in size) in response to light and when looking at near objects. These responses should occur symmetrically (the same for both eyes), even when someone naturally has a slight difference in the size of their pupils. When one eye is exposed to light, the other eye also constricts.
Overview and Facts about Unequal Pupil Size
Here are some examples of possible causes of significant anisocoria. Anisocoria is a difference in the pupil size between the eyes. The iris regulates the amount of light entering the eye by enlarging or shrinking the pupil unequal pupils usually indicate size. Below is an example of a small right pupil and a larger one in the child’s left eye. Though many causes of anisocoria are benign and some people only notice some blurry vision and/or light sensitivity, it can be a sign of a serious and potentially life-threatening neurological problem. Pupil size is a fascinating aspect of human anatomy that plays a crucial role in vision.
Usually both pupils are about the same size and respond to light equally. Horner’s syndrome includes a droopy eyelid, pupil constriction, decreased sweating, and possibly eye redness. It occurs due to conditions such as tumors, upper spine disease, stroke, disease in the neck or chest, and MS, which can affect sympathetic stimulation of the nerves that control the pupils. For most people with anisocoria, there are no noticeable symptoms beyond the uneven pupil sizes. However, if anisocoria is accompanied by other symptoms, it’s essential to seek medical attention immediately. The nerves controlling the muscles that dilate the pupil are part of the sympathetic (“fight or flight”) nervous system.
Anisocoria
Anisocoria is the medical name for your pupils being of different sizes. It’s usually a temporary issue, but it can be a sign that something inside your body is seriously wrong. Go to the ER if you notice anisocoria and have eye pain, vision loss or other symptoms that make you think something’s not quite right. Which type of healthcare provider you’ll need to see for anisocoria depends on what’s causing it and how it affects your body.
Inflammation of the iris (iritis) and certain types of glaucoma cause unequal pupils, but this finding is usually overshadowed by severe eye pain. While minor variations in pupil size are often harmless, there are specific situations where you should seek medical attention for unequal pupils. These symptoms could indicate a more serious underlying condition that requires prompt evaluation and treatment.