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