Solar retinopathy

Photic retinopathy is damage to the

eye An eye is a sensory organ that allows an organism to perceive visual information. It detects light and converts it into electro-chemical impulses in neurons (neurones). It is part of an organism's visual system. In higher organisms, the ey ...

retina The retina (; or retinas) is the innermost, photosensitivity, light-sensitive layer of tissue (biology), tissue of the eye of most vertebrates and some Mollusca, molluscs. The optics of the eye create a focus (optics), focused two-dimensional ...

, particularly the

macula The macula (/ˈmakjʊlə/) or macula lutea is an oval-shaped pigmented area in the center of the retina of the human eye and in other animals. The macula in humans has a diameter of around and is subdivided into the umbo, foveola, foveal avas ...

, from prolonged exposure to

solar radiation Sunlight is the portion of the electromagnetic radiation which is emitted by the Sun (i.e. solar radiation) and received by the Earth, in particular the visible light perceptible to the human eye as well as invisible infrared (typically p ...

or other bright light, e.g.,

laser A laser is a device that emits light through a process of optical amplification based on the stimulated emission of electromagnetic radiation. The word ''laser'' originated as an acronym for light amplification by stimulated emission of radi ...

s or arc welders. The term includes solar, laser, and welder's retinopathy and is synonymous with retinal phototoxicity.Mainster, Martin A; Turner, Patricia L. (2006). "Retinal Injuries from Light: Mechanisms, Hazards, and Prevention". ''Retina'' (4 ed.). Elsevier Mosby. pp. 1857-70. It usually occurs due to staring at the Sun, watching a

solar eclipse A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby obscuring the view of the Sun from a small part of Earth, totally or partially. Such an alignment occurs approximately every six months, during the eclipse season i ...

, or viewing an

ultraviolet Ultraviolet radiation, also known as simply UV, is electromagnetic radiation of wavelengths of 10–400 nanometers, shorter than that of visible light, but longer than X-rays. UV radiation is present in sunlight and constitutes about 10% of ...

Illuminant D65 A standard illuminant is a theoretical source of visible light with a spectral power distribution that is published. Standard illuminants provide a basis for comparing images or colors recorded under different lighting. CIE illuminants The Inte ...

, or other bright light.^{/sup>

Signs and symptoms

* Long-term reduced eyesight

Visual perception is the ability to detect light and use it to form an image of the surrounding environment. Photodetection without image formation is classified as ''light sensing''. In most vertebrates, visual perception can be enabled by ph ...
Sefic-Kasumovic S, Firdus H, Alimanovic E, Ljaljevic S, Sefic M. " ye injuries caused by an eclipse of the sun" ''Med Arh.'' 2000;54(1):41-4. Kallmark FP, Ygge J. "Photo-induced foveal injury after viewing a solar eclipse." ''Acta Ophthalmol Scand.'' 2005 Oct;83(5):586-9.
* Central or paracentral scotoma

A scotoma is an area of partial alteration in the field of vision consisting of a partially diminished or entirely degenerated visual acuity that is surrounded by a field of normal – or relatively well-preserved – vision.

Every normal mamm ...

Vision loss

Visual or vision impairment (VI or VIP) is the partial or total inability of visual perception. In the absence of treatment such as corrective eyewear, assistive devices, and medical treatment, visual impairment may cause the individual difficul ...
due to solar retinopathy is typically reversible, lasting for as short as one month to over one year. The fundus changes are variable and usually bilateral, mild cases often show no alteration and moderate to severe cases show a foveal yellow spot on the first days after exposure. After a few days it is replaced by a reddish dot often surrounded by pigment.

Permanent holes and lesions are possible; prognosis worsens with dilated pupils or prolonged exposure.

Pathophysiology

Although it is frequently claimed that the retina is burned by looking at the Sun, retinal damage appears to occur primarily due to photochemical injury rather than thermal injury. The temperature rise from looking at the Sun with a 3-mm pupil only causes a 4 °C increase in temperature, insufficient to photocoagulate. The energy is still phototoxic: since light promotes oxidation, chemical reactions occur in the exposed tissues with unbonded oxygen molecules. It also appears that central serous retinopathy can be a result of a depression in a treated solar damaged eye.Chen JC, Lee LR
"Solar retinopathy and associated optical coherence tomography findings."
''Clin Exp Optom.'' 2004 Nov;87(6):390-3.

The duration of exposure necessary to cause injury varies with the intensity of light, and also affects the possibility and length of recovery.

Diagnosis

A person with photic retinopathy may notice an impairment in their vision, for example a spot that does not go away after a reasonable recovery time, or blurring. They may also have eye pain or headaches. Vision impairment is usually in both eyes, but ''can'' be in just one. Impairment of a person with 20/20 vision usually ends up being about 20/40 or 20/60, but can be better or far worse.Solar Retinopathy: Etiology, Diagnosis, and Treatment
/ref>

A doctor examining an eye with retinopathy may be able to see no signs at all, or a slight macular edema

Macular edema occurs when fluid and protein deposits collect on or under the macula of the eye (a yellow central area of the retina) and causes it to thicken and swell ( edema). The swelling may distort a person's central vision, because the ma ...
, which is a sort of blister on or under the macula

The macula (/ˈmakjʊlə/) or macula lutea is an oval-shaped pigmented area in the center of the retina of the human eye and in other animals. The macula in humans has a diameter of around and is subdivided into the umbo, foveola, foveal avas ...
, an oval colored spot normally visible to an eye doctor on each person's retina

The retina (; or retinas) is the innermost, photosensitivity, light-sensitive layer of tissue (biology), tissue of the eye of most vertebrates and some Mollusca, molluscs. The optics of the eye create a focus (optics), focused two-dimensional ...
.

But while even that edema

Edema (American English), also spelled oedema (British English), and also known as fluid retention, swelling, dropsy and hydropsy, is the build-up of fluid in the body's tissue (biology), tissue. Most commonly, the legs or arms are affected. S ...
goes away, within a few days the patient will generally develop a discoloration of the retina at the injured point, often yellow or white, turning red over the next few weeks.

Treatment

Photic retinopathy generally goes away on its own over time, but there is no specific treatment known to be reliable for speeding recovery. One path sometimes attempted, which has unclear results, is to treat the initial macular edema with corticosteroid

Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex of vertebrates, as well as the synthetic analogues of these hormones. Two main classes of corticosteroids, glucocorticoids and mineralocorticoids, are invo ...
s.

Prognosis

Generally speaking, people diagnosed with photic retinopathy recover visual acuity completely within two months,Solar Retinopathy — American Academy of Ophthalmology
/ref> though more severe cases may take longer, or not see complete recovery at all.

See also

* Retinopathy

Retinopathy is any damage to the retina of the eyes, which may cause vision impairment. Retinopathy often refers to retinal vascular disease, or damage to the retina caused by abnormal blood flow. Age-related macular degeneration is technically in ...

References

7. ^ Stokkermans TJ, Dunbar MT. "Solar retinopathy in a hospital-based primary care clinic." J Am Optom Assoc. 1998 Oct;69(10):625-36. {{PMID, 9805443

Eye diseases
Ophthalmology}