Radiation retinopathy is damage to

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 ...

due to exposure to

ionizing radiation Ionizing radiation (or ionising radiation), including nuclear radiation, consists of subatomic particles or electromagnetic waves that have sufficient energy to ionize atoms or molecules by detaching electrons from them. Some particles can travel ...

. Radiation retinopathy has a delayed onset, typically after months or years of radiation, and is slowly progressive. In general, radiation retinopathy is seen around 18 months after treatment with external-beam radiation and with brachytherapy. The time of onset of radiation retinopathy is between 6 months to 3 years. An exposure to doses of 30-35 grays (Gy) or more is usually required to induce clinical symptoms, however, retinopathy may develop after as little as 15 Gy of external-beam radiation. A reported safe dose is : per week in five fractions of .

Signs and symptoms

Clinically, affected people may not have symptoms or may complain of decreased visual acuity. Ophthalmic examination may reveal signs of retinal vascular disease, including cotton-wool spots, retinal bleeds, microaneurysms, perivascular sheathing, capillary telangiectasis,

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 ...

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 ...

, and disc edema. Capillary non perfusion, documented by

fluorescein angiography Fluorescein angiography (FA), fluorescent angiography (FAG), or fundus fluorescein angiography (FFA) is a technique for examining the circulation of the retina and choroid (parts of the fundus) using a fluorescent dye and a specialized camera. S ...

, is commonly present, and extensive retinal

ischemia Ischemia or ischaemia is a restriction in blood supply to any tissue, muscle group, or organ of the body, causing a shortage of oxygen that is needed for cellular metabolism (to keep tissue alive). Ischemia is generally caused by problems wi ...

can lead to neovascularization of the retina, iris, and disc. Staging of radiation retinopathy has been proposed.

Pathophysiology

Radiation retinopathy is very similar to other vascular diseases.

Diabetes Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ap ...

and radiation primarily damage the retinal capillaries. Diabetes results in early loss of

pericyte Pericytes (previously known as Rouget cells) are multi-functional mural cells of the microcirculation that wrap around the endothelial cells that line the capillaries throughout the body. Pericytes are embedded in the basement membrane of blood ca ...

s and thickening of the basement membrane. Radiation however, damages the

endothelial cells The endothelium is a single layer of squamous endothelial cells that line the interior surface of blood vessels and lymphatic vessels. The endothelium forms an interface between circulating blood or lymph in the lumen and the rest of the vessel ...

Diagnosis

Treatment

The management of radiation retinopathy is similar to that for diabetic retinopathy and includes focal laser therapy to reduce macular edema or panretinal photocoagulation to treat zones of ischemia and neovascularization. Anti-vascular endothelial growth factors have been recently used for the treatment of radiation retinopathy. Monitoring of visual acuity in all cases and early referral to the

ophthalmologist Ophthalmology ( ) is a surgery, surgical subspecialty within medicine that deals with the diagnosis and treatment of eye disorders. An ophthalmologist is a physician who undergoes subspecialty training in medical and surgical eye care. Followin ...

is warranted.

References

{{Reflist, refs= {{cite book, last=American Academy of Ophthalmology, title=Retina and vitreous, year=2012, isbn=9781615251193, edition=2011-2012 {{cite journal, last=Gupta, first=Abha, author2=Dhawahir-Scala, Felipe , author3=Smith, Amy , author4=Young, Lorna , author5= Charles, Steve , title=Radiation Retinopathy: Case report and review, journal=BMC Ophthalmology, date=1 January 2007, volume=7, issue=1, pages=6, doi=10.1186/1471-2415-7-6, pmc=1855313 {{cite journal, last=Finger, first=PT, author2=Mukkamala, SK , title=Intravitreal anti-VEGF bevacizumab (Avastin) for external beam related radiation retinopathy., journal=European Journal of Ophthalmology, date=Jul–Aug 2011, volume=21, issue=4, pages=446–51, pmid=21218391, doi=10.5301/EJO.2011.6213 {{cite journal, last=Finger, first=PT, author2=Kurli, M , title=Laser photocoagulation for radiation retinopathy after ophthalmic plaque radiation therapy., journal=The British Journal of Ophthalmology, date=Jun 2005, volume=89, issue=6, pages=730–8, pmid=15923510, doi=10.1136/bjo.2004.052159, pmc=1772675 Disorders of choroid and retina