Download MBBS Ophthalmology PPT 28 Diseases Of The Cornea 2 Lecture Notes

DISEASES OF THE CORNEA

Department of Ophthalmology

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Viral keratitis

n Herpes simplex keratitis

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n Herpes Zoster keratitis

n Adenoviral keratitis
Herpes simplex virus

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n DNA Virus

n Infection is common upto 90% of the population-

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most of it is subclinical

n Humans are the only natural reservoirs

n Source of infection ?

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direct contact with the lesions,
by salivary droplets
fomites
by asymptomatic virus shedding carriers

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n HSV-1 causes infection over face ,lips and

eyes (mucocutaneous distribution of

trigeminal nerve)

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n HSV-2 causes genital herpes

n Infection can be
- Primary

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- Recurrent
HSV infection

n Congenital ocular herpes
- skin vesicles

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- eye ds
- microencephalopathy

n Neonatal HSV keratitis
- 2 days to 2 weeks

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n Primary ocular herpes

n Recurrent ocular herpes

Primary infection

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n Occurs in early childhood

n Uncommon during first 6 mts

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n Transmission through droplet infection or

direct innoculation

n May be subclinical or fever,malaise and

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URTI

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VIRAL KERATITIS

HERPES SIMPLEX KERATITIS

Primary

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?

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Vesicular blepharitis

?

Follicular conjunctivitis

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?

Keratitis Punctate

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keratitis

Dendritic ulcer

Recurrent infection

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n 36% at 5 yrs

n 63% at 20 years

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n Activated by various trigger factors
- fever
- surgery
- systemic illness
- immunosupression etc

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RECURRENT

HERPES SIMPLEX KERATITIS

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PUNCTATE EPITHELIAL KERATITIS


DENDRITIC ULCER

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FLOURESCEIN STAIN ROSE BENGAL STAIN

Geographic ulcer

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HERPES SIMPLEX

EPITHELIAL KERATITIS

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TREATMENT

?

Topical antivirals Acyclovir eye oint. 3%

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Ganciclovir gel 0.15%

Triflurothymidine drops 1%

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Vidarabine oint. 3%

?

Cycloplegics

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? Debridement of ulcer edges
? Supportive measures

? Topical steroids ?

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Metaherpetic keratitis / Neurotrophic

epithelial keratitis
Metaherpetic keratitis /

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Neurotrophic epithelial keratitis

n Occurs in patient with previous HSV

epithelial disease

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n Due to impared corneal innervation

n Nonhealing sterile ulceration

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n Round ,oval ulcers with grey thickenned

rolled up margins

n Complication ? scarring , neovascularization,

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necrosis , perforation, 2 bacterial infection

Treatment

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n Bandage contact lens

n Topical antibiotics

n Tear substitutes

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n PK


HERPES SIMPLEX STROMAL KERATITIS

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Disciform Stromal endothelitis

n

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Recurrent form- 25% of ocular herpes

n

Delayed hypersensitivity reaction to HSV

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antigen

n

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Stromal inflammation

+

Endothelial damage

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corneal edema, KP's

Descemets folds

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corneal sensations

IOP +/_

?

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Topical steroids + antivirals

DISCIFORM ENDOTHELITIS

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HERPES SIMPLEX STROMAL KERATITIS

STROMAL NECROTIC KERATITIS

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n

Active viral invasion

+

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Tissue destruction

?

Necrotic cheesy white infiltrates

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?

Stromal vascularization

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?

Treatment topical steroids

antivirals

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cycloplegics

n Oral aciclovir 400mg b.d. for 1 year reduces

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the rate of recurrence by 45%


HERPES ZOSTER OPHTHALMICUS

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n

Varicella zoster virus

n

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Latency Gasserian ganglion

n

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Ophthalmic div. of 5th nerve

n

50% have ocular lesions

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n

Unilateral

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n

Systemic features

n

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Cutaneous lesions

n

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Ocular lesions

n Seen more in older age group - >75yrs

n Systemic ? fever , malaise and eruptions

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preceded by sever neuralgic pain

n Ocular manifestations are uncommon

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HERPES ZOSTER OPHTHALMICUS

? Ocular lesions

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Lids Keratitis

Conjunctivitis SPK

Scleritis Dendritic

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Iridocyclitis Nummular

Secondary glaucoma Disciform

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Acute retinal necrosis Trophic

Motor nerve palsies Exposure

Optic neuritis

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NUMMULAR KERATITIS
TREATMENT OF HZO

SYSTEMIC THERAPY

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LOCAL THERAPY

?

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Oral antivirals Acyclovir -

Ocular lesions

800mg x10days

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Valciclovir

Topical acyclovir

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Topical steroids

?

Analgesics

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Cycloplegics

Anti glaucoma drugs

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?

Systemic steroids

Artificial tears

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?

Amitryptyline

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Tarsorrhaphy

Keratoplasty

?

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Cimetidine

Protozoal kerititis

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n Acanthamoeba

n Microsporidia
ACANTHAMOEBA KERATITIS

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Free lying amoeba soil, sewage, air

fresh, well, sea water

Ocular infection CL wearers using home made saline

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Swimming in contaminated water

Mild trauma

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Opportunistic infection

Orthokeratology

Life cycle

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n 2 stages

- Trophozoit stage

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- Cyst stage - dormant


n Symptoms:

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- foreign body sensation
- photophobia
- severe pain

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ACANTHAMOEBA KERATITIS

SEVERE PAIN disproportional to signs

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SIGNS
Epithelial stippling with

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microcystic edema

Dendritiform appearance of

epithelium

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Radial Keratoneuritis

Ring infiltrate

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Stromal infection ? overlying epithelium may

be intact

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Stromal neovascularization is never seen even

in sever and longstanding cases

Scleritis

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ACANTHAMOEBA

CYSTS KERATITIS
ACANTHAMOEBA KERATITIS

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Diagnosis Treatment

n High index of suspicion

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n Neomycin drops 1%

n KOH wet mount

n Calcofluor white stain

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n

Propamidine isethionate0.1%

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drops

n Culture on E.coli enriched

non nutrient agar

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n

Polyhexamethyl biguanide

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0.02% drops

n Confocal microscopy

n PCR of corneal biopsy

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n

Chlorhexidine 0.02%

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specimens

n

Penetrating keratoplasty

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