Clinical experience and careful slit lamp examination could point toward an etiological diagnosis of infective keratitis but Methods for rapid detection of microbial agents and confirmation of clinical diagnosis are very important adequate management of this serious condition like culture and direct microscopic smear examinations of the corneal scrapes. [4]
In the present study, 150 samples from eyes with infective corneal ulcer were studied. All of patients were subjected to detailed history taking, clinical ophthalmological examination, and microbiological laboratory investigation.
In our study, The most susceptible persons to infective corneal ulcers were old age > 60 years in 48.7% of cases, not In accordance with Srinivasan et al who found that the most susceptible persons to infective corneal ulcers were adult of 31–60 years (59% of 434 cases studied) due to outdoor activity of this age group more than old age in their countries. [5]
The susceptible gender also varies according community. In our study, males were more commonly affected with the disease than females (60% versus 40% of 150 cases investigated), the ratio being 3:2. This was comparable with the study conducted by Bharathi et al who reported 65.1% cases to be males and 34.9% to be females. [6] And in another study male to female ratio was 1:1 [7]
Due to the nature of our government, Most of the patients were from rural areas (96%). Farmers represented 77 cases (51.3%) followed by housewives 55 cases (33.3%). The rest of cases were workers and students (15.4%). Not In accordance with our results, Sedhu et al who reported that housewives are more affected (21%) than farmers (16.9%), this could be referred to the higher incidence of contact lens wearers in their communities. [8]
Trauma by plant origin was the commonest risk factor reported in in 92 cases (61.3 %), and only 4 cases had a history of wearing contact lenses and 7 cases had allergic keratoconjuctivitis with topical steroid use. 19 cases had a history of previous eye surgery. And the risk factor was not defined in the rest of cases.
This was in agreement with Basak et al who stated that the majority of the cases in their study gave a history of trauma (88%). [9]
On the other hand, Bourcier et al reported that contact lenses were the main risk factor (50.3% in cases of infective corneal ulcers). [10]
Additionally, there was a statistically significant relationship between trauma and the type of the isolated organism (p value = 0.008). Ocular trauma was the risk factor in all cases of positive fungal culture. This was in agreement with Maung et al who reported that the ocular trauma in the agricultural society was the main cause of fungal ulcer. [11].
Corneal ulcer size was less than 5 mm in diameter in 80 cases (53.3%) This was in agreement with Bharathi et al who reported that 66.6% of cases in their study presented with small corneal ulcers. [1]
Increased depth of the ulcer, larger stromal infiltrates and presence of hypopyon were common in corneal ulcers with positive microbiological studies. This was proven in our results by the statistically significant relation between positive microbiological studies and each of the extent of stromal infiltrates (p-value = 0.001) and presence of the hypopyon (p-value < 0.001).
In the present study, when culture results were analyzed, microorganisms were isolated in 58.45 % of the 142 corneal scrapes obtained from microbial infective corneal ulcer. This figure was close to the report of Srinivasan et al were positive culture obtained in 68.4 % of cases [5], but was lower than the reports from Upadhyay et al [12] who reported 80% and from Dunlop et al who reported 81.7%. [13]
Pure fungal growth was the most prevalent culture result (42.25%) followed by pure bacterial growth (14.79%). In 1.41% of the cases, a mixed growth of bacterial and fungal was found. In 41.5% of the cases, culture was negative. The fungal ulcer was also predominant in 59% of cases, than bacterial ulcer in 42% of cases in a study performed by Basak et al; [9] Etiological pattern of corneal ulceration varies with geographic region, climate and tends to vary over time. [14]
Aspergillus flavus was the commonest fungus and was isolated from 24 cases followed by Aspergillus niger which was isolated from 15 cases, followed by aspergillus fumigateus which was isolated from 14 cases and Candida albicans which was also isolated from 7 cases.
Staphylococcus aureus was the commonest bacteria isolated from 12 cases followed by Pseudomonas aeruginosa which was isolated from 9 cases followed by streptococcus non hemolyticus which was isolated from 2 cases.
Mixed growth of Aspergillus niger + staphylococcus aureus was found in two cases.
In our study, treatment was started by Empirical topical antimicrobial treatment in addition to adjuvant drugs ( cycloplgics, anti-glaucoma therapy and antibiotics for secondary bacterial infection).
After microbiological examination; if the organism was detected, the antimicrobial was modified according to smear and culture.
Systemic antimicrobial treatment was given only in severe and deep ulcers, but it was not given as a routine, this fact was reported by Upadhyay et al. [15]
In the present study, there was successful treatment outcome with complete healing of keratitis by scarring, which was achieved in 142 cases (94.67%). Only 6 cases (4%) required evisceration due to aggressive presentation from the start and keratoplasty was performed for 2 cases (1.33%) (Fig. 4). Healing time was about 4–8 weeks in bacterial keratitis and 6–12 weeks in fungal keratitis.
In conclusion, the mainstay of management of infective corneal ulcers is early identification of pathogens and proper selection of antimicrobials. Evaluation of epidemiological and microbiological profile of infective keratitis of a region can significantly contributes in adequate and appropriate management of this sight threatening condition.