Radiation effects on Eye & Periorbital Tissues

A recent article in the Red Journal has a nice summary of radiation effects on eye and periorbital tissues. You should be reading the full text but for those who are too busy here is the summary.

Ocular Risks From Orbital and Periorbital Radiation Therapy: A Critical Review. V. Swetha E. Jeganathan, Andrew Wirth and Michael P. MacManus. International Journal of Radiation Oncology*Biology*Physics Volume 79, Issue 3, 1 March 2011, Pages 650-659

The full article is available at Sciencedirect

Structure Acute RT effects Late RT effects
Eyelids Loss of eyelashes (~ 20 Gy in 2 Gy/#), Skin desquamation (as skin elsewhere) and erythema, Meibomian gland dysfunction (33% risk of chronic xeropthalmia with 20 -24 Gy) Cutaneous telengeiectasis, ciliary madarosis depigmentation (>50 Gy), scarring of eyelid with entropion, disturbances in growth of eyelashes
Conjunctiva Acute conjuctival injection, watering and discomfort (>30Gy). Differentiate from viral conjunctivitis which is more painful, lasts longer and can cause nodal enlargement Conjuntival telengiectasia (> 30Gy), chronic conjunctivits, conjunctival squamous metaplasia and conjunctival keratinization ( > 50 Gy); symblepharon and permanent scarring of conjunctiva ( > 60 Gy)
Lacrimal Gland Very common during course of RT but dose volume estimates not available. Manifest as xerophthalmia Atrophy & fibrosis of Gland (> 50Gy/ 20 Gy SF), corneal vascularization & opacification ( > 57 Gy), Keratoconjunctivitis Sicca ( >60 Gy). Latency of effect 4 - 10 year with 30 - 35 Gy and < 1 year with > 57 Gy. Tolerance dose for entire gland estimated around 30 - 40 Gy. Illappreciated effect is canalicular fibrosis secondary to RT, typically observed with doses > 60 Gy. Paclitaxel can increase risk further.
Cornea Mostly 2ndary to dry eye. Punctate epithelial erosions (30 - 50Gy), Corneal edema (40 - 50 Gy), corneal ulceration ( > 60 Gy) Rarely corneal conjunctivazation ( > 50 Gy)
Iritis Transient Irits (10 Gy SF) Persistent Iritis (>70 Gy with conventional frractionation); Neovascular glaucoma is a rare complication. Typically after ischemia of iris and angle
Lens NA Cataract formation. Emami estimates are 10 Gy for TD5/5, Hall estimates 50% risk after 1 Gy exposure in childhood. 2.5 - 6.5 Gy has a 33% risk of progressive cataract after 8 - 10 years
Retina NA Radiation Retinopathy (severe if involves macula) - Risk increases steeply after 50 Gy dose. TD 5/5 - 45 to 50 Gy, Threshold dose 30 - 35 Gy. Hyperfractionated RT can reduce risk.
Optic Nerve NA Radiation induced Optic Neuropathy (RION) 0% at doses ≤50 - 55 Gy, 3% -7% between 55 - 60 Gy. Toxicity lowered for pituitary tumors. Fraction size < 1.9 Gy significant sparing effect.
Add a New Comment
Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-ShareAlike 3.0 License