Australian Doctor 14th February 2025 | страница 33

Prognosis

The severity of chemical and ther-

A

B

mal burns determines the prognosis

of the affected eye . This ranges from

full recovery to blindness from limbal

stem cell failure and corneal scarring

and vascularisation .

INFECTIVE KERATITIS

URGENT ophthalmic review is necessary

for infective keratitis as it threatens the vision of the affected eye . Infective keratitis can be bacterial , fungal , parasitic or viral ( see figure 8 ). Bacterial keratitis is the most common cause because of the use of contact lenses and is often caused by skin flora , including Staphylococcus aureus , Streptococcus pneumoniae and pseudomonas . These organisms enter through a break in the epithelium . The two types of fungi that infect the cornea are filamentous fungi , that is fusarium and aspergillus , and yeast , for example , candida . Acanthamoeba , which is found in soils , streams , lakes

Figure 9 . A protruding nylon suture following corneal transplantation .

A . Broken and exposed 10 / 0 nylon suture at 2.30 o ’ clock on the limbus ( arrow ).

B . Removal of the broken suture with fine plain forceps under topical anaesthesia .

and swimming pools , is the primary

parasite of the cornea . The main cause

fusarium is contaminated contact

distinguish between the infil-

and HSV . Bacterial , fungal and acan-

about the importance of contact lens

of viral keratitis is HSV-1 .

lens solution . Acanthamoeba is

trates of bacterial or fungal kerati-

thamoebal keratitis requires inten-

hygiene with daily cleaning , use of

History

Infective keratitis presents with

more common in contact lens wearers and agricultural workers . The use of tap or tank water or swim-

tis ( see figures 8C-D ), which appear as white to yellow in colour and are located at varying depths within

sive topical antibiotics that may be fortified to increase corneal penetration . Clinical response is monitored

fresh contact lens solutions , regular changing of lens cases and handwashing . Contact lenses must not be

unilateral pain , intense redness ,

ming with contact lenses are risk

the corneal stroma . Acanthamoe-

closely , and the antibiotic modified

worn beyond their use-by dates .

photophobia , sensation of an FB and reduced vision . Bacterial and fungal keratitis may additionally exhibit purulent discharge ,

factors . Typically , the pain is out of proportion to the corneal signs . With HSV-1 keratitis , there is often a history of oral cold sores , and

bal infiltrates in the early phase can be mild with non-specific epithelial irregularities , for example , branching patterns ( see figure 8E )

according to the sensitivities . More severe keratitis is managed in a hospital setting . Fungal and acanthamoebal treatment may be required for

CASE STUDIES

Case study one

CARLOS , a 46-year-old male , pre-

whereas acanthamoebal keratitis

the patient may have had previ-

and later show deeper stromal infil-

up to six months to prevent recur-

sents complaining of irritation in his

presents with worsening photo-

ous bouts of keratitis and possibly

trates , classically ring-shaped . HSV

rent infection .

left eye for the past three days . The

phobia over several weeks . Patients

reduced vision from scarring .

keratitis demonstrates a character-

HSV keratitis can be managed

eye is watering , but there is no puru-

with HSV keratitis exhibit tearing and may not experience any pain . Herpes zoster keratitis , in contrast ,

Examination

The visual acuity is reduced because

istic dendritiform ulcer ( see figure 8F ) that stains with fluorescein and cobalt blue light .

with topical and / or oral antivirals . Topical aciclovir 3 % ointment five times a day for 7-10 days or an oral

lent discharge . He has a history of corneal transplantation two years ago for keratoconus .

is very painful and is associated with skin blisters in the distribution of ophthalmic division of the

of the opacity of the infiltrate . The larger the infiltrate and closer the proximity to the visual axis , the

Management

Urgent ophthalmic referral is

antiviral such as valacyclovir 500mg tds for seven days can be prescribed . Recurrent lesions may require low-

On examination , his visual acuity is 6 / 9 corrected . There is conjunctival injection superotem-

trigeminal nerve ( V1 ).

worse the level of vision . Infectious

required for intensive antimicrobial

dose prophylaxis .

porally at the limbus . With good

Immunocompromised patients or those on corticosteroids have an increased risk of fungal keratitis as

keratitis causes intense ciliary and conjunctival injection , more than expected even for smaller infil-

treatment . The level of vision will be further assessed , tonometry performed , the size and depth of the

Prognosis

Delayed or ineffective treatment of

illumination and magnification , a protruding nylon suture is noted ; this is covered by a small bead of

fungi usually infect already defec-

trates . The activity of the keratitis

infiltrate documented , and signs of

infective keratitis can cause corneal

mucus ( see figure 9A ). Another

tive epithelium . In immuncompro-

is indicated by the overlying epithe-

thinning and the extent of the over-

scarring , thinning , melting , perfora-

buried suture is noted at 3 o ’ clock .

mise , an FB sensation with a history

lial defect . There may also be ante-

lying epithelial defect noted . A cor-

tion and potentially endophthalmi-

Fluorescein staining confirms the

of trauma , especially with vegetable

rior chamber inflammation and

neal scraping will be performed to

tis , which may result in permanent

presence of an overlying epithelial

matter such as a tree branch , raise

hypopyon , especially with pneumo-

identify the organism by microscopy ,

vision loss or even the removal of the

defect and no aqueous leak ( Seidel

suspicion for a fungal cause .

coccus and moraxella .

culture and sensitivity to antibiotics .

affected eye .

negative ).

A recent common source of

It is not possible to clinically

PCR is available for acanthamoeba

Educate contact lens wearers

Under topical anaesthesia and