Biomedical subjects
Publications and source records attributed to Prashant Garg.
Though penetrating keratoplasty for keratoconus secondary to vernal keratoconjunctivitis (VKC) invariably carries a good prognosis, the postoperative course may be complicated by recurrent epitheliopathy. Despite good medical control of VKC shield ulcer is still a possibility.
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PURPOSE: To report an unusual manifestation of anterior polar cataract. METHODS: Observational case report. A 35-year-old woman presented with localized inferior corneal edema associated with a white nodular lesion on the iris. The anterior lens capsule was deficient centrally with scrolled edges and an underlying subcapsular opacity. The nodule was removed surgically and subjected for histopathologic examination. RESULTS: The histopathologic examination of the white nodular lesion showed parallel collagen fibers that were positive for collagen on the Masson trichrome stain. Correlating with clinical features, these findings were suggestive of dislocated anterior polar cataract. CONCLUSION: Anterior pyramidal cataract may dislocate spontaneously and present as an anterior chamber foreign body and may even lead to corneal endothelial cell loss.
PURPOSE: To evaluate the host and agent factors in the progression of mycotic keratitis through the microbiologic evaluation and histologic study of human corneal buttons obtained at the time of therapeutic keratoplasty. DESIGN: Retrospective noncomparative consecutive case series. MATERIALS: One hundred sixty-seven corneal buttons from 148 patients of microbiologically diagnosed and treated cases of mycotic keratitis who underwent therapeutic keratoplasty between January 1995 and May 1998. METHODS: Therapeutic penetrating keratoplasty, review of microbiologic results, histopathologic and microbiologic evaluation of the corneal buttons of mycotic keratitis MAIN OUTCOME MEASURES: Histologic evaluation of the buttons for morphologic changes, degree and distribution of inflammatory cells, presence or absence of fungal filaments, and their degree and distribution within the corneal buttons. RESULTS: The diagnosis of fungal infection was made on corneal scrapings in 36 cases; whereas in 131 (78%), the fungus was grown in cultures and identified as Aspergillus in 55 (42%), Fusarium in 42 (32%), unidentified hyaline fungi in 22 (17%), dematiaceous (unidentified) in 4 (3%), and others in 8 (6%). The mean interval between diagnosis and keratoplasty was 19 (+/-40) days. From the keratoplasty specimen, the fungus was identified at histologic examination in 127 of 167 (76%) buttons and grown by culture techniques in 76 of 115 (66%) buttons. The fungal species identified in the corneal button were Fusarium in 30 (39%); Aspergillus in 25 (33%); unidentified hyaline in 19 (25%), and others in 2 (3%). Fungus-positive corneal buttons had early surgery (mean, 15 days) compared with fungus-negative (39 days) corneal buttons (P = 0.0005), with 93% fungus positivity in the buttons removed within 2 weeks and 42% after 2 months. In the fungus-positive buttons, there was an inverse correlation between the degree, distribution of inflammatory cells, and fungal filaments (r = -0.255, P = 0.024; r = -0.199, P = 0.027), respectively. The factors necessitating an early keratoplasty were heavy fungal load, deeper penetration of fungus, and possibly insufficient inflammation to combat infection. A granulomatous reaction was noted in the posterior stroma and around the fragmented Descemet's membrane in 23 buttons (13.8%), independent of fungal species. Inflammation was unaffected by elimination of fungus and increasing interval between diagnosis and treatment. CONCLUSIONS: Rapid progression of mycotic keratitis in the early phases is by agent factors such as heavy load and deeper penetration of the fungus, insufficient inflammatory response, and possibly relative ineffectiveness of antifungal agents. Progression in the later phase of mycotic keratitis need not necessarily be agent mediated; it could be either host-modulated, species-related, or drug resistance, thereby suggesting that ideal treatment regimens should include sensitivity-based antifungal therapy aided by in vivo monitoring of fungal filaments.
PURPOSE: To report the epidemiological features and laboratory results of 1,352 cases of fungal keratitis diagnosed at the L.V. Prasad Eye Institute (LVPEI) in south India. METHODS: The medical and microbiology records of 1,352 culture proven cases (1,354 eyes) of fungal keratitis diagnosed at the LVPEI between January 1991 to December 2000 was retrospectively reviewed for demographic features, risk factors, seasonal variation, and laboratory findings. RESULTS: Males (962) were affected significantly more (p< 0.0001) than females (390). Of 1,352 patients, 853 (64.4%) were in the younger age group (16-49 years). Ocular trauma predisposed to infection in 736 (54.4%) of 1,354 eyes. There was a higher incidence of fungal keratitis during the monsoon and winter than summer. A fungal cause was established by smears of corneal scrapings in 1,277 (95.4%) eyes. The potassium hydroxide preparation (KOH), Calcofluor white (CFW), Gram-, and Giemsa-stained smears revealed fungus in 1,219 (91.0%), 1,224 (91.4%), 1,181 (88.2%), and 1,139 (85.1%) eyes, respectively. Fusarium(506, 37.2%) and Aspergillus species (417, 30.7%) predominated the hyaline fungal spectrum (1,133) and Curvularia species (39, 2.8%) were the highest among the dematiaceous isolates (218). CONCLUSIONS: To the best of our knowledge, this review presents the epidemiological features and laboratory results of the largest series of fungal keratitis ever reported in the literature. Keratomycosis is predominant in young adults with trauma as the major predisposing factor. With fungal keratitis being a major ophthalmologic problem in the tropical regions of the world, data available on the epidemiological features of a large series would greatly help medical practitioners at primary and secondary health care centers in the management of the disease. A simple KOH preparation of corneal scraping alone is highly beneficial in confirming the diagnosis.
PURPOSE: To determine the sensitivity, specificity, and predictive values of Gram and potassium hydroxide with calcofluor white (KOH+CFW) stains in the diagnosis of early and advanced microbial keratitis, a retrospective analysis of comparative data from a prospectively collected database was done. METHODS: Patients with nonviral microbial keratitis seen at L.V. Prasad Eye Institute between February 1991 and December 1998 were included in the study. The type of bacteria seen on Gram stain was determined from 251 corneal scrapings from patients with early keratitis and 841 corneal scrapings from patients with advanced keratitis. The presence of fungi in corneal scrapings was determined by KOH+CFW stain of 114 and 363 scrapings from patients with early and advanced keratitis, respectively. The smear findings were compared with culture results to analyze specificity, sensitivity, and predictive values of the staining techniques. RESULTS: The sensitivity of Gram stain in the detection of bacteria was 36.0% in early and 40.9% in advanced keratitis cases; however, the specificity was higher in both groups (84.9% and 87.1%, respectively). Comparatively, the sensitivity and specificity of fungal detection were higher using KOH+CFW in early (61.1% and 99.0%, respectively) as well as advanced keratitis (87.7% and 83.7%, respectively). Predictive values were high for KOH+CFW in fungus detection, while they were poor for Gram stain in bacteria detection. In advanced keratitis cases, the false positives were higher in fungal detection (16.3%) than in bacterial detection (10.3%), while the false negatives were significantly higher in bacterial detection compared with fungal detection (59.1% versus 12.3%, p< 0.0001). In early keratitis, on the other hand, both false positives and false negatives for bacterial detection were significantly higher than fungal detection. CONCLUSIONS: Decisions can reliably be based on KOH+CFW stain of corneal scrapings for initiation of antifungal therapy in mycotic keratitis. The results of Gram stain, on the other hand, have limited value in therapeutic decisions for bacterial keratitis. Therefore, the search for a better modality for early and efficient diagnosis of bacterial keratitis needs to continue.
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Posterior capsular re-opacification can occur following Nd-YAG capsulotomy. This necessitates multiple capsulotomies with its potential complications. We report one such case and discuss possible predisposing factors and preventive measures for this condition.
PURPOSE: To review the possible aetiological factors, ocular complications and their management in patients of Stevens-Johnson syndrome with ocular involvement, seen at a tertiary eye care centre. METHODS: We retrospectively reviewed the medical records of patients with Stevens-Johnson syndrome seen between 1987-1998 at L V Prasad Eye Institute. The demographic and possible aetiological factors data causing Stevens-Johnson syndrome were collected. The details of the ocular examination and treatment were collected and examined to determine the pattern of presentation, complications, treatment response and outcome. RESULTS: A total of 95 patients, 40 males (42.10%) and 55 females (57.89%), were identified during the 11-year period. A majority of the patients (n = 53; 55.78%) were between 20 and 40 years of age. All patients had bilateral involvement and most (n = 93; 97.89%) had bilateral symmetrical presentation. The duration from the onset of symptoms to the time of presentation at the institute varied from 6 days to 18 years with most patients presenting after one year (n = 39; 41.05%). The most commonly identified possible causative factor was drugs (n = 55; 51.89%). No definitive cause was identified in 37 (38.94%) patients, and 3 (3.15%) patients had a history of viral fever preceding the onset of Stevens-Johnson syndrome. The best corrected visual acuity at initial presentation was 6/12 or better in 32 (33.68%) patients. Lid abnormalities were observed in 87 (91.51%) patients, conjunctival abnormalities in 92 (96.84%) and corneal complications in 93 (97.89%). All patients were managed medically and 26 (27.36%) patients underwent surgery. CONCLUSION: Stevens-Johnson syndrome remains an important cause of severe visual loss and ocular morbidity, both of which significantly affect the quality of life. Not many medical or surgical options are available even in tertiary eye-care centres. Future advances in immune modulation techniques may prevent many of the sequelae that continue to occur despite the best possible medical care.
PURPOSE: To report a case of peripheral infiltrate between the flap edge and limbus, which appeared on the first postoperative day after laser in situ keratomileusis (LASIK). METHODS: A 22-year-old man underwent uneventful bilateral simultaneous LASIK but developed a thick band of infiltrate between the flap margin and limbus extending from 2 o'clock to 9 o'clock in both eyes. The flap edge was not involved. The infiltrate was more concentrated at the periphery and faded centrally and progressed diffusely into the interface leading to typical diffuse lamellar keratitis. RESULTS: The infiltrate responded to topical prednisolone acetate 1% eye drops. CONCLUSIONS: This entity was referred to as LASIK-induced bilateral peripheral infiltrative keratitis with a probable immune-mediated etiology.
BACKGROUND: To determine the antibacterial activity of newer fluoroquinolones and compare their activity between ciprofloxacin-susceptible and resistant bacterial isolates from patients with keratitis and endophthalmitis. MATERIALS AND METHODS: The minimum inhibitory concentration (MIC) of ciprofloxacin, ofloxacin, levofloxacin, gatifloxacin and moxifloxacin was determined for 123 bacterial isolates, using E test. Among the 123 isolates, 68 were gram-positive (Staphylococcus spp, Streptococcus spp, Corynebacterium spp, Bacillus spp.) and 55 were gram-negative (Pseudomonas aeruginosa). The bacterial isolates were divided into three groups: susceptible/intermediate/resistant to ciprofloxacin. The MIC values for various fluoroquinolones were compared between the three groups and between gram-positive and gram-negative bacteria. RESULTS: For gram-positive isolates, median MICs of fourth generation fluoroquinolones were lower than second generation. The median MIC was lowest for gatifloxacin and moxifloxacin (0.094 mg/ml) in ciprofloxacin-susceptible isolates of gram-positive bacteria. For ciprofloxacin-susceptible gram-negative bacteria, the median MIC of ciprofloxacin (0.19 mg/ml) was significantly lower than ofloxacin, levofloxacin, gatifloxacin and moxifloxacin (1.5, 0.5, 0.5 and 2 mg/ml respectively). Ciprofloxacin-resistant isolates of gram-positive bacteria showed higher MIC of levofloxacin, moxifloxacin and gatifloxacin though they remained susceptible to them. None of the fluoroquinolones were effective against ciprofloxacin-resistant gram-negative bacteria. Overall, for gram-positive bacteria, median MICs of levofloxacin, moxifloxacin and gatifloxacin were below ciprofloxacin, the MIC of gatifloxacin and moxifloxacin was equal for gram-positive bacteria. CONCLUSIONS: Levofloxacin, gatifloxacin and moxifloxacin are statistically more effective against gram-positive bacteria, the latter two being equally effective. Ciprofloxacin remains the most effective fluoroquinolone against gram-negative bacteria.
PURPOSE: To examine the hypothesis that initial smear examination results have a significant bearing on the management and outcome of suspected microbial keratitis. MATERIALS AND METHODS: One hundred and seventy consecutive patients with suspected microbial keratitis were included in a prospective nonrandomized comparative study and their detailed clinical and microbiological data (smears and cultures of corneal scrapings) were captured on a predesigned corneal ulcer database. Patients were divided into two groups: Group 1 included 68 patients with corneal scrapings negative in smears while Group 2 included 102 patients with corneal scrapings positive in smears. The two groups were compared for their clinico-microbiological profile, management and clinical outcome. The outcome was noted at three months. Fisher's exact test was applied for statistical analysis. RESULTS: Cultures were sterile in 57.3% of patients in Group 1 compared to 17.6% in Group 2. Scrapings that grew S. pneumoniae, gram-negative organisms, fungi and Acanthamoeba were more often positive in smears (18.6%, 11.8%, 19.6% and 2.9% respectively). While data on duration of prior treatment was not available, prior medication made no significant difference to smear results. More (79.3%) patients of Group 1 had small infiltrate size ( CONCLUSIONS: Initial smear examination helps in instituting specific therapy thereby improving the outcome in cases of microbial keratitis. Positive smears indicate greater severity of disease and prior medication may not be a significant cause of smear negativity.
Infection of a self-sealing tunnel incision is a rare but vision-threatening complication of cataract surgery. We describe two cases of side port infection following an uneventful phacoemulsification. Nocardia was isolated in one case. Both the cases were worsening on medical treatment and were successfully treated by therapeutic keratoplasty.