Gita Satpathy

Demographic pattern, predisposing factors and management of ulcerative keratitis: evaluation of one thousand unilateral cases at a tertiary care centre

Purpose:   To determine the predisposing factors, special clinical manifestations and the management of presumed microbial ulcerative keratitis.

Comparative Evaluation of Topical versus Intrastromal Voriconazole as an Adjunct to Natamycin in Recalcitrant Fungal Keratitis

OBJECTIVE To compare the efficacy of topical voriconazole and topical natamycin with that of intrastromal voriconazole and topical natamycin in patients with recalcitrant fungal keratitis. DESIGN Randomized clinical trial. PARTICIPANTS Forty eyes of 40 patients with fungal keratitis (positive smear or culture results or both) larger than 2 mm, involving up to two thirds of the stromal depth, and not responding to topical natamycin therapy for 2 weeks were recruited. INTERVENTION The patients were randomized to receive either topical 1% voriconazole therapy (n = 20) or intrastromal injections of voriconazole 50 μg/0.1 ml (n = 20). The patients in both groups continued topical natamycin 5% every 4 hours until the ulcer healed. MAIN OUTCOME MEASURES Primary outcome measure was best spectacle-corrected visual acuity (BSCVA) 3 months after intervention, and secondary outcome measures were time to healing and the size of the scar. RESULTS The patients in both groups had comparable baseline parameters. The mean BSCVA after treatment was 1.295 ± 0.5 logarithm of the minimum angle of resolution (logMAR) units in the topical group and 1.692 ± 0.29 logMAR units in the intrastromal group. The visual acuity after treatment was significantly better in the topical voriconazole group (P = 0.008). Nineteen patients receiving topical voriconazole and 16 patients who were given intrastromal voriconazole healed with therapy. CONCLUSIONS Topical voriconazole seems to be a useful adjunct to natamycin in fungal keratitis not responding to topical natamycin. Intrastromal injections did not offer any beneficial effect over topical therapy.

Randomized clinical study for comparative evaluation of fourth-generation fluoroquinolones with the combination of fortified antibiotics in the treatment of bacterial corneal ulcers.

Purpose: Comparative evaluation of efficacy of monotherapy with moxifloxacin (0.5%) or gatifloxacin (0.3%) with combination therapy of cefazolin (5%) and tobramycin (1.3%) in treatment of bacterial corneal ulcers. Methods: Patients diagnosed with bacterial keratitis (ulcer diameter 2-8 mm) were randomized to 1 of the 3 treatment groups (tobramycin 1.3% and cefazolin 5%, gatifloxacin 0.3%, or moxifloxacin 0.5%). After obtaining corneal scrapings, assigned study medication was instilled hourly for 48 hours and tapered as per clinical response. Healing of ulcer, duration to cure, adverse reactions, antibiogram profile, treatment failures, final visual acuity, and corneal opacity size were evaluated. Results: A total of 61 patients were enrolled [cefazolin and tobramycin (n = 20), gatifloxacin (n = 21), and moxifloxacin (n = 20)]. Overall, 57 patients (93%) healed on treatment. On comparison of the mean time taken to heal, no statistically significant difference was found among all the 3 treatment groups (P = 0.98). Positive bacterial culture was obtained in only 38 patients (62%). There was no significant difference in the bacterial isolates in each treatment group. There were 4 (7%) treatment failures (perforation or nonhealing ulcer): 1 (5%) each in moxifloxacin and gatifloxacin group and 2 (10%) in fortified antibiotics group. All regimens were well tolerated. Conclusion: The study failed to find a difference in the efficacy of monotherapy with fourth-generation fluoroquinolones in the treatment of bacterial corneal ulcers of 2-8 mm size when compared with combination therapy of fortified antibiotics.

Risk factors for graft infection in India: a case-control study

Aim: To study the demographic, clinical, and microbiological profile and the risk factors for graft infection following penetrating keratoplasty. Methods: 50 eyes of 50 consecutive patients with graft infection after an optical penetrating keratoplasty were included as cases; 50 eyes of 50 patients with no graft infection were included as controls. The main variables evaluated in this study included the clinical and microbiological profile, sociodemographic status, suture related problems, persistent epithelial defects, and ocular surface disorders. Results: Cultures were positive in 43 (86%) eyes and Staphylococcus epidermidis (67.4%) was the most common organism isolated. Infection could be resolved with treatment in 37 (74%) eyes. In eight (16%) eyes the graft melted and a repeat penetrating keratoplasty had to be performed. Only 6% of the cases could achieve a best corrected visual acuity of 6/18 or better after resolution of the infection. In multivariate logistic regression analysis persistent epithelial defect (OR (95% CI): 3.0 (1.17 to 8.33)), suture related problems (OR (95% CI): 3.6 (1.39 to 9.25)), and ocular surface disorders (OR (95% CI): 2.4 (0.93 to 6.03)) were found to be statistically significant risk factors for graft infection following an optical penetrating keratoplasty. Conclusions: Staphylococcus epidermidis is the commonest organism responsible for post-keratoplasty microbial keratitis. Persistent epithelial defects, suture related problems, and ocular surface disorders are the major risk factors predisposing to graft infection.

Role of 0.02% polyhexamethylene biguanide and 1% povidone iodine in experimental Aspergillus keratitis.

Purpose. To determine the efficacy of 0.02% polyhexamethylene biguanide and 1% povidone iodine in experimental Aspergillus keratitis. Methods. Aspergillus fumigatus keratitis was induced by corneal intrastromal injection of spores in 24 healthy rabbits that were randomly divided into four groups of six rabbits each. Drugs used were 5% natamycin (standard antifungal), 0.02% polyhexamethylene biguanide (PHMB) (test drug), 1% povidone iodine (test drug), and 0.5% hydroxypropylmethyl cellulose (HPMC) (control). Results. The average healing times of the ulcer were 21.5 ± 3.08 days with 5% natamycin, 27.8 ± 2.28 days with 0.02% PHMB, 36.4 ± 2.57 days with 1% povidone iodine, and 38.2 ± 4.74 days with 0.5% HPMC. While no corneal perforations occurred with natamycin treatment, one perforation was noted with PHMB, three perforations were noted with povidone iodine, and five perforations were noted with controls. Conclusion. Polyhexamethylene biguanide (0.02%) is a moderately effective drug for experimental Aspergillus keratitis, but 1% povidone iodine is not effective.

Slime production is essential for the adherence of Staphylococcus epidermidis in implant-related infections

A total of 32 Staphylococcus epidermidis isolates from indwelling device-related infections such as endophthalmitis following intraocular lens (IOL) implantation, intravenous catheter-related sepsis and orthopaedic implant infections, were studied for slime production and adherence to artificial surfaces. Of these, 21 (65.6%) isolates were slime positive by the Congo Red agar method and 24 (75%) were adherent to artificial surfaces by the quantitative slime test. The majority (19 out of 24; 79.1%) of the adherent bacteria were slime producers. Antibody to slime raised in rabbits was able to inhibit the adherence of all 24 bacteria designated as adherent by our quantitative test. It seems that slime is indispensable for the sessile mode of attachment, leading further to the development of biofilms on the indwelling devices.

Evaluation of tear samples for Herpes Simplex Virus 1 (HSV) detection in suspected cases of viral keratitis using PCR assay and conventional laboratory diagnostic tools

Background Herpes Simplex Virus (HSV) keratitis is a leading cause of corneal blindness. Definitive laboratory diagnosis is essential for timely management. Collection of corneal scrapings in patients with advanced epithelial keratitis and corneal thinning poses perforation risks; tear fluid is a feasible and convenient alternative but has not been widely evaluated for HSV detection. Methods Tear fluid alone (229) or along with corneal scrapings (153) from patients of suspected herpetic keratitis was tested for HSV-1 antigen by indirect immunofluorescence assay, virus isolation in Hep 2 cells and PCR to amplify the 111 bp region of the thymidine kinase (tk) coding gene and the 144 bp region from the DNA polymerase coding gene of HSV. Results HSV 1 antigen was detected in 31/229 (13.53%) tear specimen and 35/153 (22.87%) corneal scrapings in immunofluorescence assay; virus was isolated from 12/229 (5.2%) tear and 17/153 (11.11%) corneal scrapings, and PCR was positive for both the genes in 32/229 (13.97%) tear specimen and 56/153 (36.66%) corneal scrapings. Conclusion Corneal scrapings yielded a significantly better HSV positivity than tears in both the PCR assay (p<0.0005) and immunofluorescence assay. PCR was much more sensitive than immunofluorescence and virus isolation. However, tears should be tested for definitive laboratory diagnosis of HSV infection whenever corneal scraping collection is not possible.

In vitro susceptibility of bacterial keratitis isolates to fourth-generation fluoroquinolones.

Purpose. To study the microbiological profile of bacterial keratitis in Northern India and to determine the antibiotic sensitivity pattern of bacterial keratitis isolates to fourth-generation fluoroquinolones. Methods. Laboratory records of all consecutive cases of clinically suspected bacterial corneal ulcers were retrospectively reviewed. Data noted included microorganism isolated and antibiotic culture sensitivity to cefazolin, tobramycin, gatifloxacin, and moxifloxacin. In vitro susceptibility toward individual antibiotics was determined and compared with the potential in vitro susceptibilities to cefazolin-tobramycin, cefazolin-gatifloxacin, and cefazolin-moxifloxacin combinations. Results. A total of 292 bacterial isolates were identified. Of these, 255 (87.3%) were Gram-positive and 37 (12.7%) were Gram-negative. Staphylococcus epidermidis (n=227, 77.7%) was the most common organism. Overall susceptibility of isolates was 95.52% to gatifloxacin, 92.83% to moxifloxacin, 90.07% to tobramycin, and 83.56% to cefazolin (p<0.000). Organisms which showed resistance to fourth-generation fluoroquinolones included Staphylococcus epidermidis, Pseudomonas aeruginosa, viridans streptococci, Streptococcus pneumoniae, Staphylococcus aureus, and Escherichia coli. Susceptibilities to gatifloxacin and moxifloxacin were comparable with each other (p=0.312) and with potential susceptibilities to cefazolin-tobramycin (p=0.479), gatifloxacin-cefazolin (p=0.134), and moxifloxacin-cefazolin (p=0.412) combinations. Conclusions. Monotherapy with moxifloxacin or gatifloxacin can be an effective alternative to cefazolin-tobramycin combination as a first-line empirical therapy for bacterial keratitis. The addition of cefazolin to a fourth-generation fluoroquinolone is of limited value.

Outcomes of therapeutic penetrating keratoplasty from a tertiary eye care centre in northern India.

Purpose: The aim was to study the outcomes and results of therapeutic penetrating keratoplasty (Th PK) at a tertiary eye care hospital in northern India. Methods: In this retrospective interventional study, a cohort of 506 eyes that underwent a Th PK for microbial keratitis was evaluated. Th PK was performed in cases of recalcitrant microbial keratitis with impending perforation (descemetocele formation) or perforation (>3 mm). Medical records were reviewed for demographic details, risk factors, ulcer and perforation size, microbiological investigations, size of donor and recipient beds, postoperative complications, and anatomical and visual outcomes. Results: Anatomical success was seen in 454 eyes (89.7%). Preoperatively, the corrected distance visual acuity was <3/60 in 495 eyes (97.8%); after performing the Th PK, the corrected distance visual acuity was <3/60 in 249 eyes (49.2%), 3/60 to 6/60 in 182 eyes (35.9%), and >6/60 in 75 eyes (14.8%). Eyes with smaller grafts (<9 mm) had better anatomical and visual outcomes compared with eyes with larger grafts (9–11 mm; P = 0.03 and >11 mm; P = 0.0). A higher success rate was achieved with pure bacterial or fungal organisms rather than with mixed infections. A higher incidence of secondary glaucoma was seen in eyes with perforated ulcers (29.36%; 111/378) than in eyes without perforation (11.71%; 15/128) (P <.01) and in eyes with larger graft sizes (>11 mm and 9–11 mm) than in eyes with smaller graft sizes (<9 mm) (P <0.01). Conclusions: Th PK has a definitive role in the management of severe and refractory keratitis with a high success in restoring anatomical integrity and providing useful vision. Better outcomes may be achieved with early intervention before perforation or limbal/scleral extension.

Whole globe enucleation versus in situ excision for donor corneal retrieval--a prospective comparative study.

Purpose: The purpose of this study was to compare the results after changing from conventional whole globe enucleation to in situ excision of donor corneas. Methods: Donor corneal tissue retrieved by enucleation (n = 50) and in situ excision (n = 50) was quantitatively evaluated prospectively, and the main parameters evaluated were endothelial cell counts, ultrasonic corneal pachymetry, microbial contamination, graft clarity, and postoperative median visual acuity at the end of 3 months. Results: Mean preoperative donor endothelial cell densities were 2174 ± 123 and 2132 ± 149 cells per millimeter square after enucleation and in situ excision, respectively (P = 0.13). The preoperative disease distribution and visual potential of recipients were comparable between the 2 groups. Corneal pachymetry was lower in the whole globe group at the end of 3 months (528 μm, enucleation group; and 539 μm, in situ group; P = 0.01). The mean postoperative endothelial cell counts were comparable in both groups at 3 months (1708 ± 104.8/mm2 for whole globe group, measured in 40 eyes, vs 1674 ± 117.4/mm2 in in situ group, recorded in 39 eyes; P = 0.18). The number of positive corneoscleral rim cultures postkeratoplasty was statistically comparable in both groups (20% in enucleation group and 24% in in situ group; P = 0.62). At 3 months, 98% and 92% of grafts had a graft clarity of ≥3+ in whole globe and in situ groups, respectively (P = 0.16). Seventy-two percent of patients in whole globe group and 67% in in situ group achieved a best-corrected visual acuity of ≥0.1. Postoperative graft infection developed in 2 cases in the in situ group. Conclusions: Changeover from whole globe enucleation technique to in situ excision technique of harvesting donor corneas demonstrated that in situ excision is a viable alternative.