|Year : 1974 | Volume
| Issue : 1 | Page : 1-7
Corneal ulcers in northern India. A correlated histological and microbiological study
AL Aurora1, RC Khandpur1, G Singh2, VN Bhatia3
1 Department of Pathology, Maulana Azad Medical College and Associated Hospitals, New Delhi, India
2 Department of Ophthalmology, Maulana Azad Medical College and Associated Hospitals, New Delhi, India
3 Department of Microbiology, Maulana Azad Medical College and Associated Hospitals, New Delhi, India
A L Aurora
Department of Pathology, Maulana Azad Medical College and Associated Hospitals, New Delhi
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Aurora A L, Khandpur R C, Singh G, Bhatia V N. Corneal ulcers in northern India. A correlated histological and microbiological study. Indian J Ophthalmol 1974;22:1-7
|How to cite this URL:|
Aurora A L, Khandpur R C, Singh G, Bhatia V N. Corneal ulcers in northern India. A correlated histological and microbiological study. Indian J Ophthalmol [serial online] 1974 [cited 2020 Aug 4];22:1-7. Available from: http://www.ijo.in/text.asp?1974/22/1/1/31387
Corneal ulcers still constitute a major cause of corneal blindness in the developing countries, leading at times to serious complications of endophthalmitis and panophthalmitis. Several workers ,,,,,,,,, have reported clinical and/or microbiological features of such ulcers. However, very few studies are available giving a correlation between the type of organism isolated and the histopathological features of such ulcers.
The present study was aimed at a comprehensive clinical, histopathological and microbiological study of cases of corneal ulcers requiring keratoplasty. Some aspects of similar cases have been reported by us earlier , .
| Material and Methods|| |
This study was carried out at Maulana Azad Medical College and associated Irwin and G. B. Pant Hospitals, New Delhi from July 1970 to November 1972. The material consisted of 167 corneal buttons and 4 eye balls. Cases of graft ulcers were excluded from this study.
The ulcers were classified microbiologically into bacterial, fungal, mixed and sterile. These were classified further on histological grounds into superficial, deep and perforated depending on whether the ulcer affected upto anterior one-third, anterior two-thirds or more than two-thirds of the thickness of the substantia propria.
Fifty-nine ulcers were the result of injury while in 112 cases a definite cause could not be ascertained. It is possible that some of these cases were also the result of a forgotten injury. However, for sake of convenience these cases have been labelled "spontaneous".
Microbiological studies, both bacterial and fungal were carried out on the material obtained from the floor of the ulcer except in a few cases of impending rupture of the ulcer where the material was obtained from the conjunctival sac. The culture studies were carried out in 95 cases only. These included 29 injury cases and 66 cases of spontaneous ulcers.
The corneal buttons and eye balls fixed in 10 per cent buffered neutral formalin were studied grossly both with unaided eye and under the dissecting microscope. Tissue pieces from corneal buttons and calottes of eyeballs taken from representative areas were processed, embedded in paraffin and sections cut at 5 µ (at 8 µ in case of eye balls). The sections were routinely stained with hematoxylin and eosin (H & E). McManus periodic acid schiff stain (PAS) and Grocott's silver methanamine were utilised to demonstrate fungi  .
An ulcer was labelled as mycotic only when tissue invasion could be histologically demonstrated.
| Results|| |
I. Clinico-pathological features
A. Spontaneous ulcers
112 spontaneous ulcers were classified into superficial, deep and perforated. The age and sex distribution is shown in [Table - 1]. The largest number of cases i.e. 42.9% (48 cases) were in the age group of 20 to 40 years and another 33 per cent (37 cases) were between 40 to 60 years. The male to female ratio of 2:1 in this series is considered of no significance as the overall sex ratio of all ophthalmic admissions was similar during the period of this study. The youngest patient was a five weeks old female child who had ophthalmia neonatorum leading to perforated ulcer. Two girls of 5 and 6 years age were grossly malnourished. One had attacks of diarrhoea for 10 days associated with sore eyes, the other was a suspected case of keratomalacia. However, vitamin A studies could not be carried out in this case.
Among the superficial ulcers there were three cases of herpetic ulcers and two of marginal ulcers of which one was due to advanced trachoma and the other was an atheromatous ulcer in an old leucomatous opacity. Two other ulcers were of mycotic origin.
Of the deep ulcers one was the consequence of advanced trachoma in which the ulcer got perforated and three ulcers were due to fungal infection in two of which perforation had occurred.
B. Injury cases
An analysis of 59 cases of ulcers due to injury are shown in [Table - 2]. The marked predominance among the males is quite obvious. The sharp injuries included fingernail, contact lens, explosives, surgery and sharp iron rod. Blunt injuries were a stroke by the tail of a cow or a mango thrown on the face. Particulate matter included coal, dust, iron and flying insects.
It will be observed that most of the injuries irrespective of their nature caused deep or perforated ulcers. Of the seven cases of burns five were caused by alkali burns of the eye accidentally. One of these got perforated. Contact lens caused perforated ulcer in one case. Cataract surgery with stitch abscess formation resulted in perforation in two cases.
II. Microbiological studies
A. Spontaneous ulcers
An analysis of culture studies of 66 cases of spontaneous ulcers [Table - 3] clearly indicated the importance of Pseudomonas pyocyanea and Staphylococcus pyogenes in causing deep or perforated ulcers. The culture was positive in 42 cases (63.6 per cent) and sterile in 24 cases (36.4 per cent). Pseudomonas pyocyanea was isolated in 18 cases, Staph. pyogenes in 6 cases, Staphylococcus (coagulase negative) in 7 cases and other bacteria in 8 cases. The organisms designated as "others" included Klebsiella and Alkaligenes faecalis in the solitary case of superficial ulcer. Of the three cases of deep ulcers, one case was positive for Klebsiella and coagulase negative Staphylococcus, the second case was positive for Pxceliomyces while Alternaria was isolated in the third case. In the last two cases fungus could not be demonstrated in the tissue sections. The four cases of perforated ulcers were positive for Coliform organisms in one case; Klebsiella Staph. pyogenes and Penicillium in the second case (tissue sections did not show any fungus); Mima polymorpha in third case; and Streptococcus fxcalis in the last case. In three cases of mycotic infection, proved both on culture and histology, Aspergillus was isolated. In one of these cases Klebsiella and Pseudomonas pyocyanea were also isolated.
It is interesting to observe that in 13 of the 15 cases of superficial ulcers the culture was either sterile or showed the presence of coagulase negative Staphylococcus. Surprisingly enough, the culture was sterile in 12 of the 27 cases of perforated ulcer. Repeated cultures in these cases might have been more fruitful to arrive at a definite conclusion. The possibility that some of the sterile cases could be due to prior medical treatment cannot be ruled out.
B. Injury cases
Microbiological studies were carried out in 29 injury cases [Table - 4]. Mycotic infection was more frequently observed in these cases than in cases of spontaneous ulcers. Mycotic ulcers with demonstrable fungi in tissue sections were observed in six cases. In three of these cases culture studies were carried out and fungus isolated. Aspergillus fumigatus had produced perforated ulcer in one case while Penicillium had caused deep ulcer in another one. In both these cases dust particles got into the eyes while working in the field. In the third case with positive culture, Aspergillus flavus was isolated. This patient had a perforated ulcer and gave history of alkali burn.
Pseudomonas pyocyanea was isolated in five cases (all perforated). Klebsiella along with Pseudomonas pyocyanea was present in two cases due to unknown foreign bodies (one deep and one perforated ulcer). Klebsiella alone was isolated in one case of superficial ulcer due to dirt particles. Staph. pyogenes was cultured from four cases (3 perforated and one deep ulcer). Bacterium Anitratum and Mima polymorpha were isolated in a perforated ulcer caused by sharp copper wire. Staphylococcus (coagulase negative) was present it 4 cases. In nine cases the culture was sterile. These cases included two superficial ulcers, three deep ulcers and four perforated ulcers.
It is obvious that the most important organisms in injury cases in the present series were Pseudomonas pyocyanea with or without Klebsiella, Staph. pyogenes and the opportunistic fungi.
| Comments|| |
The normal cornea is protected from the injurious agents in the environment by the blinking reflex of the eye lids, constantly reformed precorneal tear film, the intact epithelium and Bowman's membrane. Any imbalance in the interplay of these factors due to malnutrition, systemic disease, injury or local change in the micro-environment can result in corneal ulceration.
Corneal ulcers have been caused by a variety of organisms, some of which follow a relentless course leading to rapid perforation. Suie and coworkers  reported a number of organisms in their series of 50 cases and Proteus vulgaris in two of their injury cases. The commonest organisms in their 33 positive cases were Staphylococcus coagulase negative (13 cases), Pseudomonas aeruginosa (9 cases) and Staph. pyogenes (4 cases). Cassady  has also stressed the importance of Pseudomonas aeruginosa in cases of corneal ulcers due to foreign body. Recently Sood et al , published their experiences in 159 cases of corneal ulcers in a predominantly agricultural region of South India. In their 136 positive cases Pseudomonas eruginosa, fungi, Staph. aureus, Diplococcus pneumonia, Mima polymorpha and Diphtheroids were the commonest organisms.
In the present series, being reported from a predominantly urban population, Pseudomonas pyocyanea, Staph. pyogenes and Staphylococcus coagulase negative were the chief isolates besides the fungi. Pseudomonas pyocyanea alone accounted for 23 of the 62 positive cases. The results in this series are different from those reported by other workers. This could be due to differences in the type of the population groups studied and their socioeconomic environments.
Mycotic infections have become of great significance quite recently due to the indiscriminate use of corticosteroids and broad spectrum antibiotics. This has been adequately highlighted by Zimmerman  , Puttana  , Kaufman and Wood  , Anderson et al  and Sood et al  . In the study by Zimmerman, in only 9 of the 54 cases, both mycological and histological studies were available. In the 54 cases, the commonest fungus was Aspergillus followed by Candida albicans. In the study of 20 cases of mycotic ulcers Puttana  also found Aspergillus as the commonest fungus. Sood et al  reporting from an agricultural area of South India found the predominance of Nocardia. Among their 37 cases 20 were due to Nocardia, 9 due to Aspergillus, 5 due to Candida albicans and 3 due to other yeast like fungi and phycomycetes. Neither Puttana  nor Sood et al  undertook any histological studies to prove tissue invasion by the isolated fungus.
In the present series of 66 non-traumatic cases three cases showed both culture positivity and tissue invasion by Aspergillus. In one of these cases, with deep ulcer, Klebsiella and Pseudomonas pyocyanea were also isolated. Penicillium was isolated in two cases and Aspergillus in another case but without evidence of tissue invasion. Candida albicans, Peeceliomyces and Alternaria were isolated in one case each, but again without tissue invasion. The only case where Penicillium was cultured as well as demonstrated in tissue was an injury case with a deep ulcer. The other two cases of mycotic ulcers due to injury were again due to Aspergillus infection. Except for one superficial ulcer due to Aspergillus, all mycotic ulcers with culture positivity and tissue invasion were either deep or perforated. It is obvious that histological. studies are of great significance in deciding the nature of the fungus responsible for the ulcer. In the present series, 5 of the 6 proved cases were due to Aspergillus.
Our experience in the urban population in India clearly indicates that severe type of corneal ulceration results from Pseudomonas pyocyanea and Staph. pyogenes. Of the fungi, Aspergillus seems to have a great capacity for tissue invasion. It is therefore imperative that infections due to these organisms be treated at the earliest and vigorously to save the eyes.
| Summary|| |
A clinico-pathological study of 167 corneal buttons and 4 eye balls has been carried out A correlation between the type of the organisms and the depth of the ulcers has beer emphasized. The organisms responsible for most extensive ulcers have been Pseudomonas pyocyanea, Staph. pyogenes and Aspergillus. It is considered imperative to demonstrate tissue invasion before labelling an ulcer mycotic in origin.
| Acknowledgement|| |
We are thankful to the Director-Principal, Maulana Azad Medical College and associated Irwin and G.B. Pant hospitals, New Delhi, for permitting us to publish this work.
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[Table - 1], [Table - 2], [Table - 3], [Table - 4]