Diseases of Uveal tract

APPLIED ANATOMY

UVEA is middle vascular coat of eyeball & from anterior it is divided to 3 as IRIS, CILIARY BODY, CHOROID.

IRIS

• thin circular disc peripherally attached to ciliary body & with a 4mm aperture PUPIL to regulate light reaching retina.
• anterior surface has a zig-zag line COLLARETTE which divides ciliary & pupillary zones.
• ciliary zone has radial streaks due to radial bv & 2rows of crypts.
• pupillary zone is smooth.
• 1st layer: Anterior limiting layer – has melanocytes & fibroblasts. It is thin in blue iris & thick in brown iris.
• 2nd layer: Stroma – has sphincter & dilator pupillae muscles, bv, nerves, WBC, fibroblasts.
• 3rd layer: Anterior Epithelial layer – continuation of pigment epithelial layer of ciliary body.
• 4th layer: Posterior Epithelial layer – continuation of nonpigment epithelial layer of ciliary body & peripherally forms PIGMENT FRILL of pupil.

CILIARY BODY

• aneriorly forms angle of chambers & has iris attachment.
• outer side is adjacent to sclera with suprachoroidal space inbetween.
• inner side is PARS PLICATA (finger-like Ciliary process) 2mm anteriorly & smooth PARS PLANA 4mm posteriorly.
• 5 layers: Supraciliary lamina (pigmented collagen), Stroma (ciliary muscle, bv,N, collagen, pigment cells), Pigment epithelium, Nonpigment epithelium, Internal limiting membrane.
• Ciliary process is the site of aqueous production.
• Ciliary muscle occupies outer part of ciliary body with parasym supply from short ciliary.N & it is a nonstriated ms with 3 parts: longitudinal & radial help in aqueous outflow, circular helps in accommodation.

CHOROID

• extends from optic disc to ora serrata.
• 1st layer: Suprachoroidal lamina – pigmented collagen. Outer space between it & sclera contains long & short Posterior ciliary bv & N.
• 2nd layer: Stroma – main bulk is formed by bv arranged in 3layers. It also has collagen, elastin, reticulum, pigment cells, plasma cells.
• 3rd layer: BRUCH’s membrane / basal lamina.

BLOOD SUPPLY:
Arterial supply by 3:

1. Short posterior ciliary.A – 2trunks from Ophthalmic.A pierce sclera around optic.N & segmentally supply choroid.
2. Long posterior ciliary.A – nasal & temporal br pierce sclera on medial & lateral sides of optic.N & reach ciliary body(iris root) through suprachoroidal space to anastomose(CIRCULUS ARTERIOSUS MAJOR) with Anterior ciliary.A to supply ciliary body. Radial br from this anastomosis anastomose at pupil margin to from CIRCULUS ARTERIOSUS MINOR.
3. Anterior ciliary.A – arises from muscular(recti) branches of Ophthalmic.A & pass anteriorly in episclera to supply sclera,conj & pierces limbus to enter ciliary body CIRCULUS ARTERIOSUS MAJOR.

Venous drainage is through VORTEX veins –>Ophthalmic.V –> Cavernous sinus.

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Congenital anomalies:

 

Heterochromia of Iris

H.iridium if one iris color differs from the other iris

H.iridis if one sector of iris differs from the remainder.

D/D acquired : heterochromic cyclitis, siderosis, malignant melanoma.

Corectopia

eccentric pupil [normal pupil is slightly nasal]

Polycoria

more than one pupil

Aniridia / Iridremia

abscence of iris [may be associated with glaucoma due to angle naomalies]

Persistant pupillary membrane

remnants of lens with pigmented stellate shreds from iris

they either float in anterior chamber or are attached to anterior surface of lens.

Coloboma of uvea

absence of iris, ciliary body or choroid.

TYpical – seen in inferionasal quadrant due to defective embryonic fissure closure.

complete coloboma extends from pupil to optic.N & causes corresponding indentation of lens.

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UVEITIS

 

inflm of uvea is always assosiated with some inflm of adjacent retina, vitreous, sclera, cornea.

Anatomical classification:

1. ANTERIOR UVEITIS – iris to pars plicata [iritis, iridocyclitis, anterior cyclitis]
2. INTERMEDIATE UVEITIS – pars plana & peripheral retina
3. POSTERIOR UVEITIS – chrioretinitis

Clinical classification:

acute is <6wks & symtomatic; chronic is insidious & asymtomatic (diagnosed from defective vision).

ETIOLOGICAL CLASSIFICATION:

Infective uveitis:

microbial invasion of uvea -

Exogenous	perforation by injury, corneal ulcer, intraocular surgery. suppurative starts as acute iridocyclitis & turns into endophthalmitis.
Endogenous /Metastatic	rarely through blood from caries, septicaemia.
Secondary	extension of infection from adjacent conjunctivitis, keratitis, scleritis, retinitis, orbital cellulitis, orbital thrombophlebitis.

Bacterial	granulomatous -tubercular, leprotic, syphilitic, brucellosis pyogenic – strep, staph, gonococci
Viral	H.simplex, H.zoster
Fungal (rare)	histoplasmosis, aspergiloosis…
Parasitic	toxoplasm …
Rickettsial	typhus

Allergic uveitis:

commom

Microbial	tubercular lesion in lungs / lymph nodes. streptococcal infection in teeth, paranasal sinuses, tonsils, prostrate, genitals.
Anaphylactic	serum sickness, angioneurotic edema.
Atopic	airborne pollen, cat dander, chicken feather, house dust, egg albumin.
Autoimmune	Rh arthritis, SLE, Reiter’s Phacoanaphylactic endophthalmitis, sympathetic ophthalmitis.
HLA associated	ankylosing spondylitis, Reiter’s, Behcet’s, VKH.

Toxic uveitis:

Endotoxins	pneumococcal/gonococcal conjunctivitis fungal corneal ulcer
Endocular	blind eyes, retinal detachment, intraocular haemorrages, intraocular tumors, phacotoxic.
Exogenous	chemicals, drugs [miotics, cytotoxic]

Traumatic uveitis:

mechanisms:

• mechanical effect
• intraocular haemorrage
• microbial invasion
• foreign body chemical effect
• sympathetic ophthalmia in other eye

Noninfective systemic diseases:

• sarcoidosis
• collagen diseases – polyarteritis nodosa, SLE, Rharthritis
• Metabolic – DM, gout
• CNS – sclerosis
• Skin – psoriasis, pemphigus, erythema nodosum, lichen planus.

Idiopathic:

pars planitis, sympathetic ophthalmitis, Fuch’s heterochromic iridocyclitis.

PATHOLOGICAL CLASSIFICATION:

Exaggerated inflm due to extreme vascularity & looseness of uvea.

Types: suppurative, nonsuppurative [granulomatous & nongranulomatous]

Suppurative uveitis	usually part of endophthalmitis/panophthalmitis. Cause: exogenous pyogens – staph, strep, pneum, gonococci, pseudomonas. whole uvea is thickened by infiltrate & necrotic. eye cavities get filled with pus.
Nongranulomatous uveitis [predominantly iris & C.body]	acute / chronic with diffuse inflm & marked symtoms:pain, photophobia, ciliary congestion (redness). Cause: Traumatic, Toxic, Allergic. marked bv dilatation & outpouring of infiltrate & fibrinous exudate. waterlogged Iris – muddy, edematous (blurred crypts), constricted pupil marked aqueous flare – exudate & infiltrate poured into anterior chamber fine granular KPs at the back of cornea. posterior synechiae (thin & tenous) – adhesions due to organised exudate between iris & lens. in severe inflm, cyclitic membrane, behind lens, due to exudate from ciliary processes. after healing, pin-point necrosis or atrophy. Chronic cases show scarring.
Granulomatous uveitis	insidious with minimal symtoms chronic inflm with the infiltrate[lymphocytes, plasma cells] transforming to epitheloid & giant cells & aggregating into nodules. Cause: foreign body, haemorrage, necrotic tissue, nonpyogenic & non-virulent organisms Iris nodules – Koeppe’s nodules near pupillary border or less common Busacca’s nodules near colleratte. [these nodules may initiate posterior synechia (thick & broad)] large mutton fat KPs at the back of cornea. necrosis in adjacent areas leads to fibrosis of involved area

Transitional forms: Autoimmune phacoanaphylactic endophthalmitis & sympathetic ophthalmia showing granulomatous pathology. Infective/suppurative uveitis by leptospirae showing nongranulomatous pathology.

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ANTERIOR UVEITIS / IRIDOCYCLITIS
symptoms & signs:

 

1. dominating symptom is a marked tenderness, moderate pain referred along 5th nerve first div towards forehead
2. deeper violish red circumcorneal congestion of ant ciliary bv
3. photophobia: irritation of 5th nerve sensory fibres
4. blepharospasm: 7th nerve motor fibres supplying orbicularis oculi
5. watery exudation: lacrimatory reflux by 7th nerve secretomotor & 5th nerve sensory
6. slightly impaired vision: ciliary spasm induced myopia, corneal edema & KPs, pupillary block due to exudates, vitreous haze, macular edema
7. mild lid edema
8. Corneal signs:

Corneal edema from toxic endothelitis
Posterior corneal opacity in chronic cases
KPs: protein-WBC deposits occupying central & inferior parts of the back of cornea
Mutton fat KPs	few but large greasy composed of macrophages ; granulomatous cause
Granular KPs	many small dirty white composed of lymphocytes; nongranulomatous cause
Red KPs	seen in haemorragic uveitis
Old KPs	shrunken faded pigmented KPs of Healed uveitis

9. Anterior chamber signs:

Aqueous cells	+ =6-10 cells
Aqueous flare	Brownian movts/ Tyndall phenomenon of suspended protein particles that leaked into aqueos from bv; marked in nongranulomatous uveitis
Hypopyon	sterile pus which settled down
Hyphaema	Haemorragic uveitis
changes in depth, shape, angle	Synechia formation

10. Iris signs:

loss of crypts pattern	due to exudate in acute phase atrophy in chronic phase & in Fuch’s heterochromic iridocyclitis
color changes: muddy hyper & depigmented	active phase healed stage
Iris nodules: Koeppe’s Busacca’s	common; small; at pupillary border large; near colleratte
Posterior synechia: segmental- causes irregular pupil annular/ring- cause seclusio pupillae, leading to Iris bombe & acute glaucoma total- deepens anterior chamber, seen in acute plastic uveitis	adhesions due to organized fibrin-rich exudation between iris & lens
Neovascularization [rubeosis iridis]	seen in some chronic cases

11. Pupillary signs:

from segmental posterior synechia; atropine dilatation shows a Festooned pupil

Small pupil	toxic irritation of sphincter pupillae & mecahnicallly by iris edema
Irregular
Ectropion/evertion of margin	due to contraction of fibrinous exudate on anterior surface of iris
diminished pupillary reaction	due to iris edema & hyperaemia
occlusio pupillae	due to organization acroos entire pupil

12. Lens changes:

Pigment dispersal on anterior capsule

exudate deposits over lens

complicated cataract – polychromatic luster & breadcrumb like early posterior subcapsular opacities

13. Anterior Vitreous changes:

inflm cells & flare [protein -tyndall effect]

COMPLICATIONS & SEQUELAE:

1. copmplicated cataract- polychromatic lustre, breadcrumb posterior subcapsular opacities, pigment left after temporary iris adhesion
2. secondary glaucoma- early [during inflm phase due to clogging of trabeculae], late [postinflmm pupil block from ring synechiae or occlusio pupillae
3. cyclitic membrane due to fibrin exudate behind lens
4. choroiditis in chronic cases
5. Retinal complicationscystoid macular edema & macular degeneration, exudative retinal traction detachment
6. Papillitis [optic disc inflm]
7. Band shaped keratopathy [calcific degeneration in chronic cases]
8. Phthisis bulbi: end stage of chronic uveitis; disorganised ciliary body due to recti pressure & aq production is lost making the eye a soft small atrphic globe.
9. Hypotony [low pressure]- temporary from acute ciliary body inflm; permanent [leading to vision loss] from chronic inflm & cyclitic membrane traction on ciliary body.

INVESTIGATIONS:

1. Haematological: TLC & DLC about inflm response, ESR for chronic inflm, serology for syphilis, toxoplasmosis, histoplasmosis.
2. X-rays for sarcoidosis & TB.

NON-SPECIFIC TREATMENT:

Local therapy:

1. Mydriatric cycloplegic drugs- [MOA- relieves sphincter & ciliary muscle spasm, prevents & breaks synechiae, reduces exudation by decreasing vascular permeability, antibodies are reached & toxins absorbed by relieving ciliary bv pressure] For mild inflm, short acting tpical drugs like cyclopentolate is used (2-3 times/day), long acting subconjunctival inj (continued for another 2-3wks) of homatropine & atropine are used if synechiae are already formed
2. Corticosteroids (prednisolone, dexamethasone, betamethasone, floromethalone)- reduce inflm & fibrotic destruction, use in allergic uveitis. (topical drops 4-6 times/day, ointment before bedtime, subconjunctival inj 1-2 times/day) [ADR- cataract, glaucoma; wt gain, peptic ulcer, osteoporosis, HTN, DM]

Systemic therapy:

1. Corticosteroids (prednisolone, dexa, beta, i.v methylprednisolone, periocular triamcinolone inj]- definite use in nongranulomatous cause due to Ag-Ab rxn. Daily for atleast 2wks in marked inflm, alternate day in non-acute cases & taperad completely in 6-8wks.
2. Immunosupressors (cyclophosphamide, chlorambucil, azathioprim, MTX) (anti Tcell cyclosporin & tacrolimus when resistant to cytotoxic agents)- last resort ot prevent blindness like in severe cases: Behcet syndrome, sympathetic ophthalmia, pars planitis, VHK syndrome.

Physical:

1. Hot fomentation – pain, circulation
2. Dark goggles – photophobia, lacrimation, blepharospasm

Specific treatment of cause:

1. antitubercular drugs
2. Pn for syphilis
3. Sulfa+pyrimth for toxopl
4. Broad antibiotics for masked infection in nongranulomatous cause

Treatment of complications:

1. early inflm glaucoma- timolol, acetazolamide for lowering IOP
2. late post-inflm glaucoma- iridectomy for ring synechiae
3. complicated cataract- lens extraction if no KPs
4. retinal traction detachment- vitrectomy
5. phthisis bulbi- enucleation

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POSTERIOR UVEITIS / CHORIORETINITIS

 

Suppurative	always occurs as a part of endophthalmitis
Nonsuppurative 3 Types:	GRANULOMATOUS or nongranulomatous grey white lesion due to exudation & infiltration hiding the red choroidal bv.
DIFFUSE	spreading lesion involving most choroid syphilitic, tuberculosis
DISSEMINATED	multiple & scattered over greater part of choroid In many cases cause is obscure
FOCAL: (location) Central Juxtacaecal / Juxtapapillary Anterior peripheral Equatorial	-Involves macular area, typical in toxopl, hitopl, TB, syphilis, visceral larva migrans. -Adjoins optic disc, like Jensen’s choroiditis in young people -Multiple & in peripheral choroid, often syphilitic.

SYMPTOMS & SIGNS: painless without external signs except for a few KPs from cyclitis. It is characterised by visual symptoms esp in a central lesion than in a peripheral lesion.

1. Blurring – mild due to vitreous haze, severe if central choroiditis
2. Photopsia – irritation(inflm) to rods-cones is interpreted by brain as flashes
3. Black floaters – large exudative clumps in vitreous
4. Metamorphopsia – raised retinal contour distorts images
5. Micropsia – due to separation of visual cells
6. Macropsia -due to crowding of visual cells
7. Positive scotoma – from the fixed lesion
8. Vitreous OPACITIES – fine, coarse, stringy, snowball
9. PATCH – In active phase, grey white raised lesion with ill-defined margins, deeper to retinal bv & hiding choroidal bv; retina is edematous. In healed stage, the lesion shows atrophic choroid with sharp margins & black peripheral clumps (D/D: degenerative conditions like pathological myopia & retinitis pigmentosa.)

Complications: inflm extension to anterior uvea, complicated cataract, vitreous degenration, macular edama, periphlebitis retinae, retinal detachment.

Non-specific Rx:

1. Corticosteroids: topical & systemic; Acute phase – posterior sub-tenon inj.
2. Immunosupressors

Specific Rx: for toxopl, TB, syphilis…

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PURULENT UVEITIS & ENDOPHTHALMITIS

 

direct pyogenic invasion first affecting anterior or posterior uvea, then progressing to retina & vitreous, resulting in purulent endophthalmitis.

Cause: staph, strep, pseudomonas, E’coli, proteus.

Exogenous spread	perforation by injury, corneal ulcer, intraocular operations
Endogenous spread	through blood from caries, septicaemia
Secondary extension	from orbital cellulitis, thrombophlebitis, corneal ulcer

Symptoms & signs of endophthalmitis:

1. severe ocular pain
2. marked vision loss
3. redness, lacrimation, photophobia
4. Lids – red & swollen
5. Conjunctiva – chemosed & circumcorneal congestion
6. Cornea – ring infiltration
7. Anterior chamber – Hypopyon, may completely fill.
8. Iris – muddy
9. Pupil – yellow reflex due to purulent exudation
10. In exogenous, margins get necrotic yellow
11. In endogenous, posterior uvea is first involved & yellow white mass is seen [AMAUROTIC CAT'S EYE REFLEX]
12. Initial rise inIOP till cilliary body is destroyed.

Rx: early is the hallmark

Topical Rx:

1. 2 concentrated antibiotic drops every 30min – amikacin/trobramycin + vancomycin/cefazoline
2. Dexamethasone QID
3. Cycloplegics QID – atropine/homatropine

Subconjunctival inj of 2 antibiotics every 12hrs

Diagnostic tap & intravitreal inj – in pars plana region (4-5mm from limbus), if no improvement, repeat after 48hrs considering culture report

Systemic Rx:

1. i.v antibiotics – amikacin+cefazoline QID for7-10days/ ciprofloxacin BD for 2-4days
2. oral corticosteroids – after 24hrs of antibiotics

VITRECTOMY – after ’48-72hrs of medical Rx’ to remove bacteria, toxins, enzymes.

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PANOPHTHALMITIS

 

purulent inflm of whole eyeball; begins as anterior/posterior uveitis & through a short stage of endophthalmitis.

Symptoms & signs:

1. severe ocular pain
2. COMPLETE vision loss; no perception of vision
3. marked redness
4. profuse watering & purulent discharge
5. constitutional: fever & malaise
6. Proptosed eye with limiting & painful ocular movts
7. Lids – red & swollen
8. Conjunctiva – chemosed, ciliary & circumcorneal comgestion.
9. Cornea – edematous
10. Anterior chamber – full of pus
11. marked rise in IOP
12. limbal perforation leads to fall in IOP

Rx: little hope in saving the eye; emergency pain & toxaemia

1. antiinflm & analgesics
2. broad spectrum antibiotics
3. Frill evisceration to avoid intracranial dissemination