Introduction
Every Year 1.5 to 2 million patients are losing the vision due corneal blindness making it second leading cause of blindness after cataract.1 Infectious keratitis is a serious concern attributing to ocular morbidity in developing countries like India and majority of the complications can be prevented, if intervened early.2 As the treatment requires topical medications for prolonged periods, the cost factor and socioeconomic status play a huge role in management and recovery.
The Microbial agent responsible for infective corneal ulcer varies from region to region. Thus, ophthalmologists need to be aware of local etiological profile of corneal ulcer endemic to the region.
Materials and Methods
A retrospective study was conducted at Minto Regional institute of ophthalmology Bengaluru, from January 2018 to January 2020. Outpatient, ward and theatre records of 876 patients in the age group between 18 to 70 years with infective corneal ulcer were retrieved, reviewed and analyzed for demographic details, risk factors, clinical and microbiological profile. Exclusion criteria includes Cases with non-infectious keratitis due to systemic autoimmune diseases, Mooren’s ulcer, phlyctenular keratitis, and vernal keratoconjunctivitis associated shield ulcer, typical viral corneal ulcers were excluded.3
After applying the inclusion and exclusion criteria, patient data including age, sex, occupation, socioeconomic status, locality, risk factors, seasonal variation and associated conditions were collected. Slit-lamp examination findings, corneal sensitivity and fluorescein staining of the cornea noted. Microbiological results obtained from corneal scrapings specimen after subjecting to Gram staining and potassium hydroxide (KOH) wet mount preparation for microscopy and culture and sensitivity testing were noted. Empirical treatment was administered to all patients, while awaiting microbiological results and was later modified according to the results and patient response. For those who failed to respond to conservative management and progressively deteriorated, therapeutic penetrating keratoplasty was considered.
Results
The demographic profile of 876 patients with infective corneal ulcer has been tabulated in Table 1. Among the 876 patients, 596 (68.04%) were males and 280 (31.96%) were females. Majority of patients, 613 (70%) belonged to age group 51-60 years and a significant number i.e., 745 (85.04%) patients belonged to low socioeconomic group and hailed from surrounding rural areas (803, 91.66%) had poor access to health care.
Majority, 526(60.04%) were involved in farming and agricultural activities and thus predisposition for vegetative injury was higher. And there was a seasonal variation with majority of cases (n = 394; 44.98%) reported from the month of July to September.
Table 1
Demographic profile of corneal ulcer at a tertiary care center in South India (n=876 patients)
Among the predisposing factors ocular injuries was the major factor leading to infective corneal ulcer accounting for 614 (70.09%) out of 876 patients. Injury with Vegetative matter 264 (30.14%) during harvesting season was the most common cause followed by wooden material 140 (15.98%), stone particles 114 (13.01%) and animal matter 96 (10.96%) respectively.
The risk factors predisposing to corneal ulceration have been summarised in Table 2.
Table 2
Predisposing risk factors for corneal ulcer (n= 876 patients)
At the time of presentation to the hospital 620 (70.77%) patients had visual acuity of <3/60 and 256 (29.22%) patients had visual acuity of >3/60 in the affected eye. Also, 657 (75%) had central corneal ulcer, 105 (11.99%) patients had peripheral ulcers while 114 (13.01%) patients had paracentral corneal ulcer.
Upon microbiological investigation 613 (69.98%) out of 876 patients were found to be culture positive. In those culture positive patients fungal organism was isolated in 410 (46.81%) and bacterial organism in 203 (23.17%). Most common fungal organism was Aspergillus species 211 (24.09%) followed by Fusarium species in 199 (22.72%). Out of 203 patients tested positive for bacteria Staphylococcus aureus was isolated in 132 (15.07%), Streptococcus pneumoniae in 45(5.14%), and Pseudomonas species in 26 (2.97%) patients (Table 3).
Discussion
Corneal ulcer is a major predicament haunting developing countries like India due to its prolonged ocular morbidity and consequent visual impairment. Prevalence of different microbial organisms varies based on geographical area and occupation population. So the awareness of microbial organisms prevalent in the local region is important for clinicians to start appropriate empirical treatment. In our study 596 (68.04%) patients were male and females accounted for 280 (31.96%) patients. In the study by Titiyal et al. also there was male preponderance with 75% patients being males.4 Of the 876 patients, 613 (69.97%) patients belong to age group of the 51-60 years, which is in concord with the findings of Li et al., where 83.21% patients were male.5
In the study done by Gupta et al., 65% of the patients were from rural area, similarly a high proportion of patients (91.66%) were from rural background in our study.6 Fungal keratitis cases were reported more between June to September in a study by Bharathi MJ et al., somewhat uniformly most of the cases (44.98%) in this study were also clustered between July and September. This higher incidence maybe attributed to the harvesting season.7
In our study 745 (85.04%) belonged to low socioeconomic group which was in accordance with Bhushan et al. study conducted at Uttar Pradesh and Bihar. People belonging to low socio econonomic status are mostly engaged in agriculture and manual labor. So these population has higher occupational risk of ocular injury. Moreover, 526 (60.04%) patients were involved in farming activities. This was coparable to studies by Jatoi et al. and Gopinathan et al.8, 9
History of ocular trauma was seen in 614(70.09%) patients, in our study which was on similar scale to the studies conducted by Assudani et al., Sethi et al., as well as Ranjini and Waddepally.2, 10, 11
Injury by vegetative material was seen in as many as 264 (30.14%) patients in our study group, Similarly in the study conducted at Uttarakhand by Chhangte et al had a higher incidence of (23.7%) injury by vegetative material. Visual acuity at the time of presentation was <3/60 in 460 (70.77%) patients which was comparable to the findings of Keshav et al.12 The culture positivity of 69.98% in our study was on similar lines to that reported by Basak et al13 and Gopinathan et al.9
Upon microbiological studies culture was positive in 613 patients, out of which majority were fungi (410) and 203 were positive for bacteria. This was similar to study by Nath et al, where 60.6% of cases had fungal etiology.14 This high incidence of fungal ulcer was due to injury by vegetative material in farmer and manual labors. However, in study by Suwal et al bacterial ulcers caused by were more common than fungal ulcers.15
In our study, the most common bacterial pathogen detected was S aureus (15.07%). Among the 410(46.81%) fungal infections, Aspergillus species accounted for 211(24.09%) and Fusarium species accounted for 199 (22.72%) of all the cases. Thus, the microbiological etiology has a geographical variation and also determined by the occupational exposure of the study population to different microbes.
Table 4
Comparison of causative organisms in different studies
|
|
Our study |
Study by Nath et al |
Study by Suwal et al |
|
Fungal isolates |
46.81% |
60.6% |
44% |
|
Bacterial isolates |
23.17% |
- |
56% |
In a study by Prakash and Kemisetty,16 86(64%) out of 134 patients underwent keratoplasty which is significantly higher compared to our study where only 202(23.06%) out of 876 patients underwent therapeutic keratoplasty following a no response or progression in spite of conservative management.
Conclusion
Fungal corneal ulcers, especially due to Aspergillus species, were the most common type, followed by bacterial corneal ulcers due to Gram-positive bacteria, mainly Staphylococcus aureus. Incidence of fungal corneal ulcer is very high among agricultural and industrial workers. Lack of awareness and delayed treatment leads to corneal blindness. This emphasizes the need for awareness among the at-risk population to seek urgent care. Knowledge of the local etiological profile shall guide clinicians in decision making regarding empirical treatment of patients with corneal ulcer.
