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physical eye injuries
Transcript of physical eye injuries
Dr. Walid Al-Zwahry Physical Injuries Of The Eye Introduction to physical eye injuries Types
agents Ultraviolet rays along seashores, observing welding arcs and during treatment of some skin diseases. Heat Dry heat: Wet heat: Fire,sprouting match,molten metals. Steam,boiling water and boiling oil. Irradiation symptoms
include eye pain & foreign body sensation Swelling
around the eye &Drooping eyelid Ciliary&injection Blurred vision Double vision Even Loss of vision Reflex lacrimation Irregular pupil What are the symptoms of an eye physical
injury? But What is Radiation?? Radiation is an energy in the form of electro- magnetic waves or particulate matter, traveling in the air. Types: Ionizing Radiation Non-ionizing Radiation Ionizing Radiation Non-Ionizing Radiation Definition Effect Electromagnetic waves, incapable of producing ions while passing through matter, due to their lower energy. disintegration of atoms With the subsequent release of subatomic paricles The energy released is SO HIGH that the binding energy of the electron is broken down And then comes off an ejection of electrons, leaving behind a positively charged atom called cation The radiation energy is lower than the binding energy of the electron Only states change Ground ---excited
The change to the irradiated is brought about as: Thermal Effect, Photochemical Effect, Photoluminescence(fluorescence) A radiation that is able to disrupt atoms and molecules on which they pass through, giving rise to ions and free radicals. (cc) image by anemoneprojectors on Flickr Physical injuries of the eye Definition: These are injuries caused to the eye by a physical agent leading to problems in the Corneal layers, Lens, Vitreous, or Retina. Infra red rays in glass blowers and bakers. Ionizing: non-ionizing: X-ray Radiotherapy Physical Eye Injury Risk Factors: •Male Gender •Occupational: Agriculture
Manufacturing •Radiation Therapy in treatment of intraocular tumors. Ionizing Radiation Effect on the eye According to Draper’s law: Damage depends on: 1-Exposure time 2-Concentration. That effect is either Direct Indirect Cellular anomalies or death Damage to blood vessels. levels of radiation causes: Engorged conjunctival vessels, Loss of corneal lustre levels of radiation causes: Exfoliation of epithelial cells, Keratitis, Corneal ulcer, Cataract, Retinal degeneration While Effect of Radiotherapy (RT) on the eye: Acute effects: Loss of eyelashes , Skin desquamation and erythema, Meibomian gland dysfunction (33% risk of chronic xeropthalmia) EyeLids Conjunctiva Acute conjuctival injection, watering and discomfort. Differentiate from viral conjunctivitis which is more painful, lasts longer and can cause nodal enlargement Lacrimal Gland affection manifests as xerophthalmia Cornea affection is mostly 2ry to dry eye, Punctate epithelial erosions, Corneal edema, corneal ulceration. Iris Transient Irits. dry eye dry eye corneal abrasions Late effects Eyelids Cutaneous telengeiectasis, madarosis, ciliary depigmentation, scarring of eyelid with entropion, disturbances in growth of eyelashes. telangiectasias & madarosis telangiectasis madarosis ectropion Conjunctiva Conjuntival telengiectasia, chronic conjunctivits, conjunctival squamous metaplasia and conjunctival keratinization; symblepharon and permanent scarring of conjunctiva. epidermalization Lacrimal Gland Atrophy & fibrosis of Gland, corneal vascularization & opacification, Keratoconjunctivitis Sicca (combines dry eye and dry mouth) Cornea Rarely corneal conjunctivazation Iris Persistent Iritis; Neovascular glaucoma is a rare complication. Typically after ischemia of iris and angle. lens Cataract formation. Retina Radiation Retinopathy (severe if involves macula) fluorescein angiogram showing severely enlarged foveal avascular zone. radiation retinopathy is characterized clinically by the development of microaneurysms, telangiectases, neovascularization, tractional retinal detachment, vitreous hemorrhage and macular edema, after exposure to radiation. Optic Nerve Radiation induced Optic Neuropathy (RION) 0% at doses ≤50 - 55 Gy, 3% -7% between 55 - 60 Gy. Fundus examination in radiation-induced optic neuropathy: ocular fundus showing flame-shaped and dot hemorrhage (bottom row, h, arrow) and cotton-wool spots (top row, bottom row, p). Effect on the eye 1-Thermal Effect: Heating effect d/t the change in energy states of atoms. Pathogenesis: Thermal effects of solar radiation by directly or indirectly viewing the sun. Presentation is within 1-4 hours of solar exposure with unilateral or bilateral impairment of central vision and central positive scotoma. C/P VA is variable, Fundus: a small yellow or red foveolar spot that fades within a few weeks .The spot is replaced by a sharply defined foveolar defect with irregular borders or a lamellar hole. 2-Photochemical Effect: on absorption of radient energy, the molecule that absorbs may decompose or chemically react to produce a unique chemical product. Photokeratitis is an example that involves a thermal lesion. Photokeratitis Damage to the corneal epithelium due to the absorption of UV-rays below 300nm, also called: Photophthalmia, Photoconjunctivitis. The damage tends to be cumulative. •Symptoms and signs: Foreign body sensation, Photophobia, Lacrimation, Blepharospasm, Redness, Oedema. • The above c/p is also seen in SNOW BLINDNESS that occurs due to exposure to UV radiation from large areas of snow, also found in Welder’s keratitis in welders who strike an arc before they wear a protective helmet. • Prophylaxis: Crooker’s glass, It cuts off all the UV- and IR- rays, To be used by those who are prone to the radiation hazard, Cinema operators, welding workers. • Treatment: Cold compresses, Pad, bandage and antibiotic ointment for 24 hours and Oral analgesics. Photoluminescence (fluorescence) • Pathogenesis: After 4-5 hrs(latent period)of UV exposure , there occurs desquamation of corneal epithelium, leading to the formation of multiple epithelial erosions. Solar retinopathy is an example that involves a thermal lesion. Photoluminescence (fluorescence): Non-Ionizing Radiation •Transmission of the spectrum Spectrum • Cornea:
290nm-1600nm Absorption of the spectrum • Tear layer: Absorbs only a small amount of radiation, absorbs UV below 290 and IR above 3000.
• Cornea: Has a similar absorption band But partially transmits UV from 290 to 315 and IR from 1000 to 3000.
• Aqueous humour: Absorbs very little or no radiation at all. • Lens:
The lens of a child absorbs UV below 310nm and IR above 2500nm.
The lens of an older adult absorbs almost all radiation below 375nm and therefore transmits very little UV radiation. No change in the IR absorption band with increasing age. But in case of lens extraction and IOL the amount of radiation reaching the retina largely increase. • Vitreous: Absorbs radiation below 290nm and above 1600nmThe retina receives the radiation transmitted by the vitreous, UV radiation received by the retina decreases with age. Effects of Ultraviolet radiation Photophthalmia,
Macular degeneration. A triangular fibro-vascular subepithelial ingrowth of degenerative bulbar conjunctival tissue over the limbus onto the cornea. Pterygium Pathogenisis The ultra violet rays caus destruction of the limbal stem cells allowing the conjunctiva to invade the cornea. Risk Factors excessive exposure to wind excessive exposure to sunlight more likely to occur in populations that inhabit the areas near the equator twice as likely to occur in men as women. Tear substitute,
Advise the patient to wear sunglasses to reduce UV exposure and decrease the growth stimulus. Management Elastoid degeneration of the conjunctival collagen stroma, Found adjacent to the limbus Pinguecula: Band- shaped keratopathy: Histology shows the deposition of calcium salts in the Bowman layer, epithelial basement membrane and anterior stroma Anterior subcapsular opacities are most associated. It has been found to be associated with the UV band from the sun. Cataract: There is a strong positive association between UV rays and the senile cataracts. NB: Effects of Visible radiation Almost all of the radiation transmitted to the retina is not harmful as the structures have evolved to remain immune to the damage.
However, the long term exposure to visible spectrum has been found to be associated with: macular degeneration,
damage to the photoreceptors
and the pigment epithelium
also Solar retinopathy. Effects of Infrared radiation: Thermal damage to tissue leading to DENATURATION, unlike the UV radiation that involves photochemical, thermal damage. Mechanism: Effects On
Cornea Opacification exfoliation Burn necrotic ulceration The posterior corneal regions show more damage than the anterior regions due to the cooling effect by the tear film to minimize anterior corneal defects. NB: On Aqueous Increase in IOP Increase in Temp. On Iris Pupillary miosis Aqueous flare Posterior synechiae Congestion Depigmentation Atrophy Lens Posterior cortical opacity anterior subcapsular opacity (acute) posterior subcapsular opacity (delayed d/t migration of the ant.) Retina Damage d/t the indirect thermal injury to the neural elements of the retina. Injury occurs in durations ranging from microseconds to several hours. (strong ass.)
.Thermal mechanism(long wavelength):
Due to the elevation of temperature of the irradiated tissue e.g. Necrotic burn. Two mechanisms have been proposed: 1-Choroidal melanoma, iris tumors, retinoblastoma have been linked to radiation, or mutation induced due to radiation that may pass onto new generations. Thermal injuries Effects: The blink reflex usually causes the eye to close in response to a thermal stimulus. Thus, thermal burns tend to affect the eyelid rather than the conjunctiva or cornea. Conjunctiva and cornea may be affected in severe cases. Patients with superficial burns often complain of symptoms similar to a corneal abrasion. Include: Common complaints Tearing,
A foreign body sensation. burns, scalds and ulcers of the eyelids, conjunctiva and cornea. On examination patient shows: Pathophysiology: The severity of an ocular burn is directly correlated with the duration of exposure the causative agent Damage 1ry: 2ry: by denaturing and coagulating cellular proteins by causing vascular ischemic damage. depth and degree of epithelial damage limbal ischemia Severity Severity of damage is determined by: The cornea may develop recurrent epithelial defects, and conjunctival invasion onto the cornea may occur as a result of the loss of stem cells responsible for renewing corneal epithelium. Prognosis: Depends on the depth of the injury.
Corneal burns are classified into 4 grades, as follows: •Grade 4 –Cornea is opaque,limbal ischemia is greater than 1/2 of the limbus, with a possibility of globe perforation very good prognosis •Grade 1 - Only corneal epithelial loss , and no conjunctival ischemia is found •Grade 2 - Some corneal edema and haze are present, and the conjunctival ischemia affects less than 1/3 of the limbus; some permanent scarring may occur •Grade 3 – Cornea has significant haziness, and limbal ischemia is less than one half of the limbus; vision usually is impaired prognosis is variable poor prognosis •Use safety glasses, goggles, or face screens during working in risky place Prevention of Burns to the Eye:
• Use a mask or goggles configured for welding •Burns from UV light source may be avoided by using sunglasses and by putting on broad-brimmed hats. Management: At emergency: 1st assess the potential for coexisting life-threatening injuries Then Ocular thermal and chemical injuries are a true ocular emergency and require immediate and intensive evaluation and treatment. First Aid for Heat Burns: •Immediately flush the eye with cool water in a sink or dish pan or under a running faucet or shower, then open and close the eyelids to force water to all parts of the eye. •Keep flushing for 30 minutes. •cover the eye with a sterile bandage or cloth (to reduce pain). •If blisters form, do not pop them. •Use a light, cool compress to reduce the pain. If a small ice pack is used, place a cloth between the ice and the skin. Management (cont.): •Prevention of infection with the use of a topical broad spectrum antibiotic. •Frequent lubrication of the ocular surface with a lubricating ointment or artificial tears helps to prevent the formation of symblepharon. •Oral analgesics (acetaminophen) given to relief pain. •Cycloplegic mydriatic (atropine) given to reduce inflammation, pain, and risk of infection. If the eyelids are significantly burned then a combination antibiotic/steroid (tobramycin/dexamethasone) ointment may also be beneficial in promoting healing and minimizing scar formation. The severe cicatricial eyelid changes that may occur with a severe thermal injury. In significant corneal edema add topical steroids but with observing the patient carefully for signs of infection. These patients should be followed very closely for signs of infection and referral to an oculoplastics specialist may also be indicated if the patient shows signs of cicatricial eyelid changes as the eyes are healing. Tobradex (3 mg/gr Tobramycin/ 1 mg/gr Dexamethasone) To remove necrotic tissue that can optimize the outcome by reducing continued inflammation. Active surgical intervention In selected cases, amniotic membrane patching may also be considered.
Amniotic Membrane Graft helps in: ocular surface reconstruction
promotes rapid epithelial healing
partially restores limbal stem cell function.
It can be considered as an effective modality for the ocular surface restoration in thermal and chemical burns. Thank you! As the property of fluorescence is inherent to the lens, the lens is capable of absorbing UV rays and concentrating the radiant energy, So that in people with IOL the UV penetrate reaching the retina, so these people must not remain in the son for a long time. section through the lens (solid arrows). This lens is average clarity for a person of 50 years of age. The amount of scaring depends on the involvement with Bowman's membrane and with the corneal stroma. A corneal burn resulting from cigarette ash accidentally being flicked into the eye. Fresh, superficial burn of the cornea Eyelid Cigarette burn .Photochemical mechanism(short wavelength):
Due to phototoxicity. 2-spring catarrh or Vernal keratoconjunctivitis (VKC)” which is a recurrent, bilateral, and self-limiting inflammation of conjunctiva, having a periodic seasonal incidence and is thought to be an allergic disorder in which IgE mediated mechanism play a role” may be associated with exposure to ultraviolet rays. And its treatment must involve wearing sun glasses. •NB: MM. RB. UV Radiation injury to the eye may be caused by: •Carbon arcs
•Electric sparks •Welder's arcs •Suntanning beds •Photographic flood lamps In addition to the sun, sources of UV radiation include the following: unprotected or long exposures to the sun, particularly at high altitude;
exposure to UV radiation reflected off snow, ice, or water;
viewing of solar eclipses. •Halogen desk lamps The symptoms typically appear 6 to 10 hours after exposure. A foreign-body sensation
Decreased visual acuity Patients experience the onset of: On Slit Lamp examination: Diffuse uptake of fluorescein stain as seen in ultraviolet keratitis indicating superficial punctate keratitis. http://lessons-in-gore.tumblr.com/post/46849080443/a-corneal-burn-resulting-from-cigarette-ash Effects of X-ray on the eye .Depigmentation
.Retinal Ischemia due to prolifrative retinopathy
(radiational retinopathy) .As an ionizing radiation, on exposure it may stimulate the growth of intraocular tumors in genetically predisposed patients (e.g. A child at risk of hereditary Retinoblastoma is contraindicated to do X-ray or CT scan) Penetration Infrared radiation Wavelengths longer than 3000 nm do not reach the earth’s surface because They are absorbed by water and carbondioxide in the atmosphere Damage from IR radiation covers only from wavelengths 780 nm to 2000 nm. .Macular burn and edema.
.True exfoliation of the lens and iris leading to TMW block and 2ry Glaucoma A patient with exfoliation. Note the increased pigment and exfoliative material in the trabecular meshwork. True Exfoliation of the Lens, Infrared Radiation