Photopsia: Definition, Description, Causes and Risk Factors
A subjective sensation of lights, sparks, or colors due to electrical or mechanical stimulation of the ocular system.
Photopsia is the presence of perceived flashes of light. It is most commonly associated with posterior vitreous detachment (PVD), migraine with aura, migraine aura without headache, retinal break or detachment, occipital lobe infarction and sensory deprivation (ophthalmopathic hallucinations). Among causes of retinal photopsia, digitalis is well known for inducing chromatopsia, and it can also cause photopsia.
Vitreous shrinkage or liquifaction, which are the most common causes of photopsia, cause a pull in vitreoretinal attachments, irritating the retina and causing it to discharge electrical impulses. These impulses are interpreted by brain as 'flashes.'
This condition has also been identified as a common initial symptom of Punctate Inner Choroiditis (PIC), a rare retinal autoimmune disease believed to be caused by the immune system mistakenly attacking and destroying the retina.
Another cause can be nervous spasms.
It can be classified according to its site of origin - either the retina or the brain. Posterior vitreous detachment and retinal break are representatives of the fomer. Less commonly, acute zonal occult outer retinopathy or mesastatic tumor also induce photospia with retinal origin. The most frequent brain-related photopsia is migraine with aura. Occipital epilepsy, although very rare, may be a diffrential diagnosis, especially for chldren.
Other Risk Factors:
Posterior Vitreous Detachment (PVD). The vitreous, a gel-like substance that fills the center of the eye and gives it its shape, attaches to the retina. Over time, the vitreous shrinks and begins to detach in places from the retina, a condition called posterior vitreous detachment, or PVD. PVD affects as many as 75 percent of people over age 65, the Royal National Institute of Blind People reports. The vitreous pulls on the retina as it detaches, stimulating the retina and causing photopsia.
- Migraines. Migraines, severe recurrent headaches caused by blood vessel spasms in the brain that last from a few hours to several days, often cause visual symptoms. Flashes of light that may look like zigzag lines, sparkles or geometric patterns often accompany migraines, the Massachusetts Eye and Ear Infirmary states. Photopsia usually appear in the peripheral areas of vision and may affect one or both eyes. Photopsia can also occur without headache, a phenomenon called an ophthalmic migraine.
- Retinal Detachment or Tear. Retinal detachment or retinal tears cause photopsia that need prompt evaluation and treatment. Permanent vision loss can result if the retina detaches from the back of the eye, especially if detachment occurs over the macula, the central point of vision on the retina. The retina loses its source of nutrients when it detaches from the eye, and since the retina contains the photosensitive cells responsible for vision, the consequences from cell death can be severe. Retinal detachment can occur after trauma or as a complication from PVD or diabetes, the Mayo Clinic states. Vitreous gel can seep under the retina through small tears or holes that occur from retinal thinning, raising up sections and disconnecting it from the eye, or a PVD can pull hard enough on the retina to pull parts of it away. Surgery, laser treatment or cryopexy, a freezing technique, all may be used to reattach the retina.
- Other Causes. Trauma such as a blow to the head can cause a person to "see stars" or flashes of light. Digitalis toxicity can also cause flashes of light, All About Vision states. Digitalis is often taken to treat heart problems.
Symptoms of photopsia may include sudden flashes of lights or 'stars.'In some cases the flashes of light can be in the form of jagged lines which last for 10 to 20 minutes. The light flashes associated with a migraine have shapes, colors and last longer. On the other hand, the flashes associated with vitreous separation are shorter and without any kind of shapes. If Photopsia is accompanied by a headache, then it's most probably a migraine headache.
It can present as retinal detachment when examined by an optometrist or ophthalmologist. Your ophthalmologist will discuss your symptoms and give you a complete eye exam. He or she will conduct a number of tests in order to understand the type and severity. Common tests your doctor may use include:
Gonioscopy - determines if fluid is properly draining out of your eye.
- Fluorescein angiography - determines the amount of damage to your eye.
- Visual fields - tests your peripheral vision.
- Optical coherence tomography - examines the thickness of the retina.
Standard vision tests like the Snellen visual acuity measurement, which quantifies your vision as 20/20 etc are unable to quantify many aspects of a visual disability due to photopsia and how the disability interferes with day-to-day functioning and overall quality of life. Responses to subjective questionnaires such as NEI VFQ-25 may be more indicative of visual dysfunction.
The phenomena of Photopsia are most often harmless but also may be a sign of important health problems. The sudden onset of Photopsia should be checked by an eye doctor. Though the possibility of something serious occurring is low, the advantages of an exam outweigh the inconveniences involved.
On rare occasions when the vitreous pulls on the retina, the resulting vitreous detachment can cause small tears or holes in the retina which could lead to a retinal detachment. The damaged part of the retina subsequently does not work properly and a blind or blurred spot in vision results. This is a serious problem which needs prompt medical treatment by an ophthalmologist. If untreated, retinal tears or holes can continue to worsen and severe vision loss can result should the retina becomes detached.
An eye examination with dilation of the pupil is the only way to determine if you have developed a tear in the retina. You should have a prompt comprehensive examination anytime you experience Photopsia, decreased vision, or if you become aware of an increase in the number or intensity of flashes or floaters. In a such an eye exam your ophthalmologist can use a variety of special instruments to look at the vitreous, the retina and the other interior parts of your eyes to determine the causes of Photopsia.
Vitrectomy: Pars plana vitrectomy (PPV) is a procedure usually reserved for complicated posterior segment disease. It has a well-known risk profile and justifiably there is reluctance to offer this surgery to treat photopsia. However the post-operative complication rate following PPV has been assessed in the setting of retinal detachment surgery or in the presence of complicated vitreoretinal disease. It may be argued that pars plana vitrectomy for photopsia, in eyes that have an established posterior vitreous detachment (PVD), may be associated with a lower incidence of both intraoperative and post-operative complications. The three main postoperative complications that one must worry about in vitrectomy are: development or progression of nuclear sclerosis cataract
, retinal detachment and choroidal or vitreous hemorrhage (bleeding) in the eye.
Pars plana vitrectomy has been reported to be a highly effective treatment for photopsia with complete resolution of symptoms recorded in 93.3% of patients in one study.
Laser Surgery: A Nd:YAG laser is used to 'disrupt' the floaters. The laser places a high energy acoustic (sound-wave) pulse close to the floater. This energy pulse disrupts/blasts the floater. Technically this procedure is termed 'vitriolysis'. Despite studies describing laser vitreolysis as a treatment for vitreous floaters, this technique is not widely practiced. The reason for this may be a combination of disappointing results, or reluctance to use Nd:YAG laser in the posterior segment of the eye. The latter may be influenced by the known complication of retinal detachment following YAG laser capsulotomy (performed after a cataract surgery), which occurs at an incidence of between 0.50% and 4.16%.
A recent study showed that laser surgery for photopsia ameliorated symptoms in only a third of patients. Furthermore the clinical improvement was only moderate in degree, subjectively being graded at no greater than 50% by 93.3% of patients. In no patient was there complete resolution of symptoms. Laser treatment led to worsening of symptoms in 7.7% of patients.
NOTE: The above information is for processing purpose. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition.
DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.