Photic retinopathy is damage to the
eye
Eyes are organs of the visual system. They provide living organisms with vision, the ability to receive and process visual detail, as well as enabling several photo response functions that are independent of vision. Eyes detect light and conv ...
's
retina
The retina (from la, rete "net") is the innermost, light-sensitive layer of tissue of the eye of most vertebrates and some molluscs. The optics of the eye create a focused two-dimensional image of the visual world on the retina, which then ...
, 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
Solar irradiance is the power per unit area (surface power density) received from the Sun in the form of electromagnetic radiation in the wavelength range of the measuring instrument.
Solar irradiance is measured in watts per square metre (W/m ...
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" is an acronym for "light amplification by stimulated emission of radiation". The fir ...
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 the Earth, totally or partially. Such an alignment occurs during an eclipse season, approximately every six month ...
, or viewing an
ultraviolet
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nanometer, nm (with a corresponding frequency around 30 Hertz, PHz) to 400 nm (750 Hertz, THz), shorter than that of visible light, but longer than ...
,
Illuminant D65
CIE standard illuminant D65 (sometimes written D65) is a commonly used standard illuminant defined by the International Commission on Illumination (CIE). It is part of the D series of illuminants that try to portray standard illumination conditio ...
, or other bright light.
/sup>
Signs and symptoms
* Long-term reduced eyesight
Visual perception is the ability to interpret the surrounding environment through photopic vision (daytime vision), color vision, scotopic vision (night vision), and mesopic vision (twilight vision), using light in the visible spectrum reflecte ...
[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 mam ...
Vision loss
Visual impairment, also known as vision impairment, is a medical definition primarily measured based on an individual's better eye visual acuity; in the absence of treatment such as correctable eyewear, assistive devices, and medical treatment†...
due to solar retinopathy is typically reversible,fovea
Fovea () (Latin for "pit"; plural foveae ) is a term in anatomy. It refers to a pit or depression in a structure.
Human anatomy
*Fovea centralis of the retina
* Fovea buccalis or Dimple
* Fovea of the femoral head
* Trochlear fovea of the fr ...
l 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.[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](_blank)
/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 macu ...
, 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 (from la, rete "net") is the innermost, light-sensitive layer of tissue of the eye of most vertebrates and some molluscs. The optics of the eye create a focused two-dimensional image of the visual world on the retina, which then ...
.
But while even that edema
Edema, also spelled oedema, and also known as fluid retention, dropsy, hydropsy and swelling, is the build-up of fluid in the body's Tissue (biology), tissue. Most commonly, the legs or arms are affected. Symptoms may include skin which feels t ...
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 involv ...
s.
Prognosis
Generally speaking, people diagnosed with photic retinopathy recover visual acuity completely within two months,
/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 inc ...
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