Microsoft Word - Editorial 26,3,10


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Editorial 
 

The Challenge of Microbial Keratitis in 
Pakistan 

 
Microbial keratitis is a common sight threatening 
disease which occurs in all parts of the world. 

 Statistics of corneal blindness from different 
countries show a range from 5-77%1. 

The disease can cause a lot of pain, discomfort and 
lead to serious visual disability if not treated properly. 
The disease poses serious challenges to both public 
health and clinical ophthalmologists in terms of 
prevention, diagnosis, treatment and final visual 
rehabilitation. 

The pathogenic factors contributing to the 
causation of microbial keratitis include exogenous 
factors, altered host tissues, and the host response. The 
exogenous factors include invasion by microbes like 
bacteria, fungi, viruses and rarely some parasites. An 
initiating event in the form of trauma (physical, 
chemical or toxic) which results in break-down of 
epithelium integrity usually precedes the microbial 
invasion of the corneal tissue. The trauma may be 
macro or micro such as produced by contact lenses 
wear2. 

The altered host tissue is affected by exposure due 
to lid deformity, tear film abnormalities, post radiation 
keratitis, corneal epithelial and stromal edema and the 
role of the local immune mechanisms. Other 
influences are altered corneal tissue secondary to 
diabetes as well as chronically diseased eyes such as 
following extensive surgery and other debilitating 
diseases or dry eyes syndrome. The role of host 
response is less specific or less well understood,  but is 
affected by the degree of inflammation, 
hypersensitivity factors, corneal edema and the release 
of enzymes such as collagenase, either by corneal 
tissue or the invading inflammatory cells. 

The sequential progression in the pathogeneses of 
bacterial corneal infections includes adhesions of the 
organism to the superficial cornea, entry of the 
organism into the corneal tissue, multiplication and 
spread of the organism. The host inflammatory 
response is then evoked in which the organism 

encounters phagocyte cells and the host immune 
response. Recent reports have described an apparent 
increased risk of development of bacterial keratitis in 
patients with extended wear soft contact lenses. The 
organisms in these cases are either pseudomonas or 
acanthamoeba. 

A fairly large number of fungi have been isolated 
from corneal ulcers. A review of published reports 
shows that the fungi encountered in cultures of 
material obtained from corneal ulcers mainly belong 
to the genera Aspergillus, Fusarium, Penicillium and 
Candida. 

For diagnostic purposes, it is recommended that 
meticulous scrapings of the infiltrate be performed 
including the base and edges of the ulcer or that a 
biopsy of the stromal abscess is taken. The material 
obtained from such scrapings should be inoculated on 
to multiple media like blood agar, chocolate agar, 
anaerobic media and Sabouraud’s agar. Material from 
the scrapping should be stained with Gram’s, Giemsa, 
Ziel-Neilson and other special stains. 

For fungal isolation, scrapping should be treated 
with 10-20% KOH. In patients with culture proven 
keratitis, initial scrapings treated with KOH or stained 
with Gram’s or Giemsa or other stains are diagnostic 
in 80-88% of cases. Recently PCR has become an 
important diagnostic possibility3. 

 The results of the Gram’s stain can be used to 
select the initial therapy4. 

Therapy of microbial keratitis should be directed 
towards the offending organism in the form of 
appropriate antibiotics and antifungal agents. Other 
supplementary therapy includes non-steroidal anti-
inflammatory agents, Steroids, Atropine and Anti-
collagenase5. 

Surgical intervention in the form of simple 
epithelial debridement of the ulcer, conjunctival flap, 
lamellar keratectomy, Keratoplasty and Tarsorrhaphy 
may at time become necessary6. 



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Non-availability of the corneal donor material is a 
problem in salvaging the vision. Keratoplasty is not 
only an effective method in dealing with the indolent 
corneal infection but is also of importance in treating 
the complications. It is the only hope in dealing with a 
corneal opacity obstructing vision. Frequently used 
Keratoplasty can thus help in saving many eyes, 
structurally and functionally, which are invariably lost 
at present7. 

The pattern of microbial keratitis in a community 
largely depends upon the socio-economic status, the 
degree of development, access to medical services, 
personal and community hygiene, the availability of 
clean water and other basic requirements for living, 
awareness of the problem, the general nutritional 
status of the community, the prevalence of other 
infectious diseases, climate, and high frequency of 
predisposing factors like trauma. It can be seen that 
the problem of corneal blindness, specially the 
infective part is largely preventable8. 

There are no community health surveys to 
indicate true incidence of the disease in our country. 
Over the counter sale of medicines and indiscriminate 
use of steroids and antibiotics is an important risk 
factor for microbial keratitis. Communities need to be 
made aware about the principles of prevention of 
ocular ocular trauma and ocular infections. The 
ophthalmic technicians and lady health workers are 
two important cadres which can help in the primary 
prevention of the disease. There is scarcity of ocular 
microbiological services. Although the National 
Program for Prevention and Control of Blindness in 
Pakistan has provided equipment for setting up 
microbiology laboratories in the 7 Centers of 
Excellence in the country, the services are not yet 
established. 

In order to address the issue of microbial keratitis 
at national level, we would like to submit the 
following recommendations. 

1. Establish regional Centers of Ocular Pathology. 
2. Initiate a Health Education Campaign on 

prevention of ocular trauma and ocular infection. 
3. Establish a national register for ocular trauma. 
4. Establish at least four Eye Banks of International 

standards, one in each province to solve the 
problems of availability of corneal donor material. 

 
REFERENCES 
1. Whitcher JP, Srinivasan M, Upadhyay MP. Corneal blindness: 

a global perspective. Bulletin of the World Health 
Organization, 2001, 79: 214–21. 

2. Hall BJ, Jones L. Contact lens cases: the missing link in contact 
lens safety? Eye Contact Lens. 2010; 36: 101-5. 

3. Shukla PK, Kumar M, Keshava GB. Mycotic keratitis: an 
overview of diagnosis and therapy. Mycoses. 2008; 51: 183-99. 

4. Khanal B, Deb M, Panda A. Harinder Singh Sethi Laboratory 
Diagnosis in Ulcerative Keratitis. Ophthalmic Res. 2005; 37: 
123-7. 

5. Jules L. Baum Initial therapy of suspected microbial corneal 
ulcers: I. Broad antibiotic therapy based on prevalence of 
organism. Survey Ophthalmol. 1979;24: 97-105. 

6. Buxton JN, Fox ML.  Conjunctival flaps in the treatment of 
refractory pseudomonas corneal abscess. Ann. Ophthalmol. 
1986; 18: 315-8. 

7. Hill JC. Use of penetrating Keratoplasty in acute bacterial 
keratitis.  Br. J. Ophthalmol. 1986: 70: 502-6. 

8. Hong LC. Affluence and changing pattern of blindness in 
Singapore. 1950-1980. In Henkind P. (ed): ACTA XXIV 
International Congress of Ophthalmology. Philadelphia, J.B. 
Lippincott Co. 1982: 1329-31. 

 
 

Prof. Nasir Saeed 
Peshawar 

 
Prof. Muhammad Daud Khan 

Peshawar