Episcleritis

After the transport of aqueous humor into the posterior chamber, it flows through the pupil into the anterior chamber where it provides oxygen and nutrition to the avascular lens and cornea. Aqueous humor then exits the anterior chamber through the trabecular meshwork and drains into Schlemm s canal which drains aqueous humor into the episcleral venous system. 

Ocular complications (iritis, episcleritis, and conjunctivitis) occur in up to 10% of patients. Five percent to 10% of patients experience dermatologic or mucosal complications (erythema nodosum, pyoderma gangrenosum, aphthous stomatitis). 

Iritis, uveitis, episcleritis, and conjunctivitis with ocular involvement... 

Inflammatory conditions Treatment of steroid-responsive inflammatory conditions of the palpebral and bulbar conjunctiva, lid, sclera, cornea, and anterior segment of the globe, such as Allergic conjunctivitis acne rosacea superficial punctate keratitis herpes zoster keratitis iritis cyclitis and selected infective conjunctivitis (when the inherent hazard of steroid use is accepted to obtain an advisable diminution in edema and inflammation [prednisolone]) vernal conjunctivitis episcleritis epinephrine sensitivity and anterior uveitis. 

The perilimbal ischemia is the breaking of the conjunctival and episcleral vessels resulting in a plus or minus spread white avascular areas around the edge of the limbus (Fig. 7.3). 

This ischemia can be trivial, limited to the breaking of the blood flux in only one vessel and not easy to detect because of being hidden in a spread conjunctival hyperemia. The conjunctival hyperemia differs from ischemia. The conjunctival hyperemia is a dilatation of the conjunctival and episcleral vessels. It signihes an inflammation as a reaction to the irritation caused by the chemical bum. It is not a sign of the gravity of the chemical bum (Fig. 7.4). 

Fig. 7.5 Very serious ocular bum by atkah (12.8% ammonia, pH = 11.5), 1 h 30 min after accident complete 360° conjunctival ischemia (none of the conjunctival or episcleral vessels are visible)...

The phosphoinositide-3 kinase (PI3-K)/Akt pathway is activated as a self-defense mechanism of RGCs against injuries inflicted by intravitreal injection of NMDA (Manabe and Lipton, 2003 Nakazawa et al., 2005), episcleral vein cauterization (Kanamori et al., 2004 Kim and Park, 2005), optic nerve clamping (Nakazawa et al., 2003), and translimbal photocoagulation (Levkovitch-Verbin et al., 2007). 

Kanamori, A., Nakamura, M., Nakanishi, Y., Nagai, A., Mukuno, H., Yamada, Y., and Negi, A. (2004). Akt is activated via insulin/IGF-1 receptor in rat retina with episcleral vein cauterization. Brain Res. 1022, 195-204. 

The topical ophthalmic application of hydroxyeicosatetraenoic acid derivatives, (III), prepared by Gamache (3) was effective in preventing ophthalmic inflammatory disorders involving cytokine secretion and used in treating conjunctivitis, iritis, uveitis, and episcleritis. 

Dilated episcleral vessels are a clue to abnormal anastamoses between branches of the external carotid artery and orbital branches of the internal carotid artery, distal to severe internal carotid artery disease. With extreme ischemia, ischemic oculopathy may develop, with impaired visual acuity, eye pain, rubeosis of the iris (dilated blood vessels), fixed dilated pupil, low-pressure glaucoma, cataract and corneal edema. 

Ocular exposure can cause pain, lacrimation, comeal ulceration, swelling, blepharospasm, and blindness as the eyes are very sensitive to the effects of mustard gas (Borak and Sidell, 1992 Dacre and Goldman, 1996 Garigan, 1996 NATO, 1973). Pathognomonic signs of mustard gas poisoning include poreelain-white areas in the episcleral... 

Sclera 3) Diffusion across sclera 4) Clearance via episcleral veins 3) In vitro permeability of human and rabbit sclera 4) Limited data on blood flow and capillary permeability... 

The uveal vessels remove drugs by bulk transport from the iris and ciliary body.The direct outflow pathway from aqueous humor through trabecular meshwork and canal of Schlemm into the episcleral vessels is another major source of drug removal from the eye. 

Because Treponema pallidum is sensitive to penicillin G, this antibiotic is the drug of choice for treatment of syphilis and syphilitic eye disease (see Table 11-1). Syphilitic eye disease can include interstitial keratitis (stromal inflammation and vascularization), episcleritis, scleritis, nongranulomatous or granulomatous iritis, iris papules (collections of dilated capillaries in the iris), chorioretinitis, papillitis, retinal vasculitis, and exudative retinal detachment. Probenecid can be added to procaine penicillin to decrease excretion of the penicillin by the kidneys, thus causing an increase in penicillin plasma levels. Penicillins are not used for the treatment of minor ocular infections such as blepharitis and conjimctivitis... 

Anterior uveitis Posterior uveitis Sympathetic ophthalmia Sclera Scleritis Episcleritis Retina... 

Clinical evaluation of patients with conjunctivitis, episcleritis, and scleritis indicates that fluorometholone acetate improves clinical signs and symptoms of inflammation significantly more than fluorometholone alcohol. Furthermore, when fluorometholone acetate 0.1% was compared with prednisolone acetate 1.0% in patients... 

Infectious Epstein-Barr Malaise, headache, fever, Eyelid hyperemia, edema, Dacryoadenitis, episcleritis,... 

Figure 25-29 Episcleritis in patient with systemic lupus erythematosus.

Flach AJ, Lavoie MD. Episcleritis, conjunctivitis and keratitis as ocular manifestations of Lyme disease. Ophthalmology 1990 97 973-975. 

Read RW, Weiss AH, Sherry DD. Episcleritis in childhood. Ophthalmology 1999 106 2377-2379. 

Ocular involvement can develop as soon as several days, to as long as years, after vesicle formation. Ocular involvement may inclnde lid edema, follicnlar conjunctivitis, corneal changes, anterior nveitis, glancoma, episcleritis, scleritis, Horner s syndrome, extraocnlar muscle palsy, chorioretinitis, optic nenritis, and scarring of the lids and lacrimal canalicnlar system. It is possible, but rare, to have ocular complications, snch as nveitis and disciform keratitis, withont any skin lesions. 

The sclera is considered avascular because it contains no capillary beds. It obtains sufficient nutrition to meet its low metabolic requirements from the episcleral and choroidal blood supplies. The episclera obtains a rich blood supply from the anterior and posterior ciliary arteries.The episclera contains two vascular supplies, a superficial vascular plexus and a deep vascular plexus. 

Episcleritis is a somewhat imcommon and nsnally benign self-limiting inflammation of the episcleral tissues. Of new... 

Episcleritis is clinically classified as either simple or nodular. Simple episcleritis is usually the milder form, being limited to a sector of the eye in approximately two-thirds of cases, but can affect the entire episclera in approximately one-third of cases. Nodnlar episcleritis is nsually more serious and involves the presence of a definitive nodule and mild to moderate discomfort. Approximately 20% to 25% of cases present as nodular. Only 2% to 5% of episcleritis progresses to scleritis. Simple episcleritis usually lasts 1 to 3 weeks, whereas nodular episcleritis has a more variable course, in some cases lasting up to 2 months. Both forms periodically recnr but become less frequent with time until the disease no longer remits. Either form may recur as the other. 

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