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Infective keratitis: A challenge to Indian ophthalmologists

2007; Medknow; Volume: 55; Issue: 1 Linguagem: Inglês

10.4103/0301-4738.29487

1998-3689

Muthiah Srinivasan,

Retinal and Optic Conditions

According to world health organization (WHO), corneal diseases are among the major causes of vision loss and blindness in the world today, second only to cataract in overall importance.1 In India, there are approximately 6.8 million people who have corneal blindness, with vision less than 20/200 in at least one eye and of these, about a million have bilateral corneal blindness. It is expected that the number of corneally blind people in India will increase to 10.6 million by 2020.2 Globally, it is estimated that ocular trauma and corneal ulceration result in 1.5 to 2 million new cases of corneal blindness annually.3 Ninety per cent of them occur in developing countries; and it has now been recognized as a silent epidemic.4 A recent national survey by the Government of India (1991-2001) estimated that corneal lesions are responsible for 9% of all blindness in our country.5 About 65% of infective keratitis of nonviral origin develops following corneal injuries. Till date there is no population-based, prospective study on infective keratitis reported in India. In 1996, Gonzales et al.6 did a retrospective population-based study in the district of Madurai, India, to estimate the incidence of corneal ulceration; and they found it to be as high as 1130 per million population. This value was ten times higher than the incidence of corneal ulceration in Olmstead county, USA, as per a study reported by Erie et al. in 1993.7 Erie had concluded that the incidence of corneal ulceration in the US rose dramatically from the 1950s to the 1980s by almost about 435% and the main contributing risk factor was contact lens wear. It is unbelievable but true that this factor is less than 2% in India as reported in this volume by Bharathi et al.89 This could be due to either less Indians wearing contact lenses or decreased incidence of patients using overnight wear and extended wear contact lenses. Even though we have a heterogeneous population, the agents causing infective keratitis have been known to be homogenous since several decades. However, there is not much shift in the spectrum of bacteria and fungi as etiological agents. This message gives better hope and knowledge in managing this problem more effectively without indulging in further planning and research. The real concern is to explore the possibility of effective management of infective keratitis, as done in developed countries. Presently we do not have adequate facilities to tackle this preventable cause of blindness at primary and secondary levels, even though the population at the greatest risk lives within that jurisdiction. We are a little better equipped at the tertiary level, but even so the main focus of attention in Medical Colleges and Regional Eye Institutes is on blindness due to cataract and more recently on that due to diabetic retinopathy. A guideline for managing infective keratitis at all levels was developed by an expert group for the South East Asian Region at the initiation of the WHO meet at New Delhi in 2004, but it has not yet been implemented.10 I am curious if the readers of the Indian Journal of Ophthalmology (IJO) have given a thought to whether we have a standard process and patronage to manage infective keratitis similar to the management of cataract. It is clear that we still lack consensus in this regard. The American Academy of Ophthalmology and International Council of Ophthalmology have developed standard treatment protocols and benchmarking in treating infective keratitis which is followed by most of their ophthalmologists. It is an ideal time for the All India Ophthalmological Society to advocate certain standards of care, at least among teaching institutes. We need to address a controversial issue about the initial management of infective keratitis (nonviral) in our population. In my opinion, we do more harm by faithfully adopting the western protocol, where 90% of corneal ulcers are caused by bacteria.11 We have several reports about a very high incidence of fungal keratitis in our population (up to 63%).12 Sir Stewart Duke Elder in his chapter on "Mycotic Ulcers" highlighted that mycotic ulcers have been one of the main ophthalmic problems in developing countries. One should resist the temptation of treating infective keratitis without having done some simple laboratory investigations, for example, an initial examination of a corneal scraping with 10% KOH and Gram's staining could easily be practiced in every center.13 The sensitivity of this simple test in detecting fungi ranges from 90-99%.1415 Jain et al.16 have for the first time reported a 97.14% sensitivity in identifying fungi from corneal ulcers by using the impression smear technique. Indian ophthalmologists have access to all the newer antibacterial and antifungal antibiotics since the dawn of this millennium including fourth generation fluoroquinolones. At the same time, we also face the ancillary problems of drug resistance by ocular isolates.1718 Second and fourth generation fluoroquinolones are no more a panacea in managing ocular infections.19 There are several reports with data being manipulated by the manufacturers to surpass each other. In this regard, Duggirala et al.20 have discussed newer fluoroquinolones in some detail. Methicillin-resistant Staphylococcus aureus exhibited a relatively high rate of in vitro resistance to all fluoroquinolones tested, including fourth generation ones.21 Most of the causes of blinding corneal pathology are preventable. Srinivasan et al.22 have now demonstrated that prevention of infective keratitis is feasible and cost-effective within the existing healthcare system. Research is another tool which can help in the management and prevention of this problem. Several clinical and basic research projects have been launched by the Government of India and other multinational agencies towards eradication of preventable blindness. Vasanthi et al.23 and Nayak et al.24 have made the going easier by applying molecular biology. Reducing the corneal blindness due to infective keratitis may take several decades. It is the light at the end of the tunnel which makes me optimistic; and the only concern now is tackling the existing one million corneally blind. For this, we need to make optimum use of state-of-the-art eye banking facilities and cutting edge technology as applied to keratoplasty procedures. It is my long felt desire to obtain accreditation for Indian eye banks. Singh et al.25 and Desai et al.26 have made initial attempts to narrow down the gap between the demand and supply of the donor corneas and seem to have succeeded to some extent. In conclusion, I would like to thank the Editor, IJO for giving me this opportunity to write my views about this "Silent Epidemic". We are happy to present this issue to the readers and hope the day is not far away when all of us will be making an active and concerted effort in reducing the burden of corneal blindness in our country.