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

Download MBBS (Bachelor of Medicine, Bachelor of Surgery) Ophthalmology PPT 28 Diseases Of The Cornea 2 Lecture Notes


DISEASES OF THE CORNEA

Department of Ophthalmology



Viral keratitis

n Herpes simplex keratitis

n Herpes Zoster keratitis

n Adenoviral keratitis
Herpes simplex virus

n DNA Virus

n Infection is common upto 90% of the population-

most of it is subclinical

n Humans are the only natural reservoirs

n Source of infection ?
direct contact with the lesions,
by salivary droplets
fomites
by asymptomatic virus shedding carriers

n HSV-1 causes infection over face ,lips and

eyes (mucocutaneous distribution of

trigeminal nerve)

n HSV-2 causes genital herpes

n Infection can be
- Primary
- Recurrent
HSV infection

n Congenital ocular herpes
- skin vesicles
- eye ds
- microencephalopathy

n Neonatal HSV keratitis
- 2 days to 2 weeks
n Primary ocular herpes

n Recurrent ocular herpes

Primary infection

n Occurs in early childhood

n Uncommon during first 6 mts

n Transmission through droplet infection or

direct innoculation

n May be subclinical or fever,malaise and

URTI








VIRAL KERATITIS

HERPES SIMPLEX KERATITIS

Primary



?

Vesicular blepharitis

?

Follicular conjunctivitis

?

Keratitis Punctate

keratitis

Dendritic ulcer

Recurrent infection

n 36% at 5 yrs

n 63% at 20 years

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


RECURRENT

HERPES SIMPLEX KERATITIS

PUNCTATE EPITHELIAL KERATITIS


DENDRITIC ULCER

FLOURESCEIN STAIN ROSE BENGAL STAIN

Geographic ulcer


HERPES SIMPLEX

EPITHELIAL KERATITIS

TREATMENT

?

Topical antivirals Acyclovir eye oint. 3%

Ganciclovir gel 0.15%

Triflurothymidine drops 1%

Vidarabine oint. 3%

?

Cycloplegics

? Debridement of ulcer edges
? Supportive measures

? Topical steroids ???





Metaherpetic keratitis / Neurotrophic

epithelial keratitis
Metaherpetic keratitis /

Neurotrophic epithelial keratitis

n Occurs in patient with previous HSV

epithelial disease

n Due to impared corneal innervation

n Nonhealing sterile ulceration

n Round ,oval ulcers with grey thickenned

rolled up margins

n Complication ? scarring , neovascularization,

necrosis , perforation, 2 bacterial infection

Treatment

n Bandage contact lens

n Topical antibiotics

n Tear substitutes

n PK


HERPES SIMPLEX STROMAL KERATITIS

Disciform Stromal endothelitis

n

Recurrent form- 25% of ocular herpes

n

Delayed hypersensitivity reaction to HSV

antigen

n

Stromal inflammation

+

Endothelial damage

corneal edema, KP's

Descemets folds

corneal sensations

IOP +/_

?

Topical steroids + antivirals

DISCIFORM ENDOTHELITIS


HERPES SIMPLEX STROMAL KERATITIS

STROMAL NECROTIC KERATITIS

n

Active viral invasion

+
Tissue destruction

?

Necrotic cheesy white infiltrates

?

Stromal vascularization

?

Treatment topical steroids

antivirals

cycloplegics

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

the rate of recurrence by 45%


HERPES ZOSTER OPHTHALMICUS

n

Varicella zoster virus

n

Latency Gasserian ganglion

n

Ophthalmic div. of 5th nerve

n

50% have ocular lesions

n

Unilateral

n

Systemic features

n

Cutaneous lesions

n

Ocular lesions

n Seen more in older age group - >75yrs

n Systemic ? fever , malaise and eruptions

preceded by sever neuralgic pain

n Ocular manifestations are uncommon


HERPES ZOSTER OPHTHALMICUS

? Ocular lesions

Lids Keratitis

Conjunctivitis SPK

Scleritis Dendritic

Iridocyclitis Nummular

Secondary glaucoma Disciform

Acute retinal necrosis Trophic

Motor nerve palsies Exposure

Optic neuritis

NUMMULAR KERATITIS
TREATMENT OF HZO

SYSTEMIC THERAPY

LOCAL THERAPY

?

Oral antivirals Acyclovir -

Ocular lesions

800mg x10days

Valciclovir

Topical acyclovir

Topical steroids

?

Analgesics

Cycloplegics

Anti glaucoma drugs

?

Systemic steroids

Artificial tears

?

Amitryptyline

Tarsorrhaphy

Keratoplasty

?

Cimetidine

Protozoal kerititis

n Acanthamoeba

n Microsporidia
ACANTHAMOEBA KERATITIS

Free lying amoeba soil, sewage, air

fresh, well, sea water

Ocular infection CL wearers using home made saline

Swimming in contaminated water

Mild trauma

Opportunistic infection

Orthokeratology

Life cycle

n 2 stages

- Trophozoit stage

- Cyst stage - dormant


n Symptoms:

- foreign body sensation
- photophobia
- severe pain



ACANTHAMOEBA KERATITIS

SEVERE PAIN disproportional to signs



SIGNS
Epithelial stippling with

microcystic edema

Dendritiform appearance of

epithelium

Radial Keratoneuritis

Ring infiltrate


Stromal infection ? overlying epithelium may

be intact

Stromal neovascularization is never seen even

in sever and longstanding cases

Scleritis

ACANTHAMOEBA

CYSTS KERATITIS
ACANTHAMOEBA KERATITIS

Diagnosis Treatment

n High index of suspicion

n Neomycin drops 1%

n KOH wet mount

n Calcofluor white stain

n

Propamidine isethionate0.1%

drops

n Culture on E.coli enriched

non nutrient agar

n

Polyhexamethyl biguanide

0.02% drops

n Confocal microscopy

n PCR of corneal biopsy

n

Chlorhexidine 0.02%

specimens

n

Penetrating keratoplasty

This post was last modified on 07 April 2022