Gilbert Smolin

Epidemiology and aetiological diagnosis of corneal ulceration in Madurai, south India

AIMS/BACKGROUND To determine the epidemiological characteristics and risk factors predisposing to corneal ulceration in Madurai, south India, and to identify the specific pathogenic organisms responsible for infection. METHODS All patients with suspected infectious central corneal ulceration presenting to the ocular microbiology and cornea service at Aravind Eye Hospital, Madurai, from 1 January to 31 March 1994 were evaluated. Sociodemographic data and information pertaining to risk factors were recorded, all patients were examined, and corneal cultures and scrapings were performed. RESULTS In the 3 month period 434 patients with central corneal ulceration were evaluated. A history of previous corneal injury was present in 284 patients (65.4%). Cornea cultures were positive in 297 patients (68.4%). Of those individuals with positive cultures 140 (47.1%) had pure bacterial infections, 139 (46.8%) had pure fungal infections, 15 (5.1%) had mixed bacteria and fungi, and three (1.0%) grew pure cultures ofAcanthamoeba. The most common bacterial pathogen isolated was Streptococcus pneumoniae, representing 44.3% of all positive bacterial cultures, followed by Pseudomonas spp (14.4%). The most common fungal pathogen isolated was Fusariumspp, representing 47.1% of all positive fungal cultures, followed by Aspergillus spp (16.1%). CONCLUSIONS Central corneal ulceration is a common problem in south India and most often occurs after a superficial corneal injury with organic material. Bacterial and fungal infections occur in equal numbers with Streptococcus pneumoniaeaccounting for the majority of bacterial ulcers and Fusariumspp responsible for most of the fungal infections. These findings have important public health implications for the treatment and prevention of corneal ulceration in the developing world.

Epidemiologic Characteristics, Predisposing Factors, and Etiologic Diagnosis of Corneal Ulceration in Nepal

Corneal ulceration is one of the most frequent causes of blindness in developing countries. Between September 1985 and August 1987, 405 patients with corneal ulceration were examined at Tribhuvan University Teaching Hospital in Kathmandu, Nepal. Males and females were equally affected. The most common predisposing cause of ulceration was corneal trauma, usually with organic agricultural materials. Microorganisms were grown from 324 (80%) of the ulcers. Pure bacterial cultures were obtained from 256 (63.2%) of the patients, whereas pure fungal cultures were obtained from 27 (6.7%) of the patients. In 41 patients (10.1%), corneal cultures yielded a mixed growth of bacteria and fungi. Of a total of 398 bacterial isolates, 124 (31.1%) were positive for Streptococcus pneumoniae, the most commonly isolated organism in the series. Other frequently isolated bacteria included Staphylococcus epidermidis, S. aureus, and Pseudomonas species. Of 68 positive fungal isolates obtained, 32 (47.0%) were identified as Aspergillus species. Candida species and Fusarium species were less commonly seen.

Idoxuridine-Liposome Therapy for Herpes Simplex Keratitis

In the treatment of acute and chronic herpetic keratitis, an idoxuridine-liposome preparation was more effective than a comparable therapeutic regimen of idoxuridine alone. Both antiviral agents were more effective than a control combination of liposome and saline.

Incidence of corneal ulceration in Madurai District, South India

OBJECTIVEnTo determine the incidence of corneal ulceration in Madurai District, South India.nnnDESIGNnRetrospective incidence study.nnnSETTINGnGeneral community.nnnPATIENTSnAll patients who reside in Madurai District and presented to an ophthalmologist in 1993 with corneal ulceration.nnnMAIN OUTCOME MEASUREnCases of corneal ulceration.nnnRESULTSn1148 cases of corneal ulceration were recorded in the medical records of those ophthalmologists who maintained records. Based upon the recorded number of cases, the annual incidence per 10,000 population was 3.4. The ratio of male to female patients was 1.6:1.0. When the estimated number of cases from those without records was added to the total number of recorded cases the annual incidence was 11.3 per 10,000 population.nnnCONCLUSIONnCorneal ulceration is a common occurrence in South India. While the true incidence of this problem is impossible to determine because of the lack of medical records, we believe our estimation of the incidence to be close to the true incidence in this community.

The Microbial Flora in Extended-Wear Soft Contact-Lens Wearers

Of 857 cultures of material collected from the eyelids, conjunctivae, and contact lenses of 51 extended-wear soft-contact-lens wearers, 44 (5%) grew potential pathogens. The aphakic patients wearing contact lenses had fewer recoverable pathogens (24 of 295 or 8%) than a group of preoperative cataract patients (63 of 295 or 21%). On five occasions, positive cultures accompanied clinical symptoms, and on three occasions, repeated cultures grew the same potential pathogen.

Antibiotic Supplementation of Intraocular Irrigating Solutions: An In Vitro Model of Antibacterial Action

PURPOSEnThe addition of antibiotics to infusion solutions for cataract surgery is becoming increasingly popular. The authors developed an in vitro model to evaluate antibacterial effects of this use of antibiotics.nnnMETHODSnClinical isolates and/or reference strains of the following organisms were examined: coagulase-negative Staphylococcus spp, Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus viridans, Streptococcus spp, Enterococcus spp, Proprionibacterium acnes, Moraxella nonliquifaciens, and Pseudomonas aeruginosa. Standardized suspensions of each organism were incubated with a control solution (Balanced Salt Solution) or Balanced Salt Solution containing the following antibiotics: vancomycin (20 micrograms/ml) or gentamicin (8 micrograms/ml) or gentamicin and vancomycin combined (8 and 20 micrograms/ml, respectively). Suspensions were incubated for 30, 60, and 120 minutes at room temperature. Samples were centrifuged, and the organisms were washed with Balanced Salt Solution before quantitative culturing. Each organism also was incubated for 48 hours in Mueller-Hinton broth with the same antibiotic concentrations.nnnRESULTSnMost of the organisms were not affected by exposure to the antibiotics for up to 140 minutes. P. aeruginosa and M. nonliquifaciens were exceptions, decreasing in colony numbers even with 30 minutes of exposure. Several Staphylococcus spp yielded variable results. All organisms demonstrated nearly complete inhibition of growth when exposed for an extended time to the appropriate antibiotic in broth.nnnCONCLUSIONSnExposure to antibiotics for a short period of time, such as during intraocular surgery, generally has no effect on organisms commonly responsible for endophthalmitis. The use of antibiotics in this manner should be critically reassessed until further study.

Tobramycin in external eye disease: a double-masked study vs. gentamicin.

A double-masked randomized study was conducted at four centers to compare the efficacy and safety of tobramycin and gentamicin ophthalmic ointment in the treatment of superficial external eye disease. Seventy-seven patients with blepharitis and/or conjunctivitis were evaluated for safety, and 56 of the 77 individuals also qualified for evaluation of drug efficacy. After a 10 day treatment regimen, 97% of the tobramycin treated patients and 91.3% of the gentamicin treated patients were clinically cured or improved. Antibacterial effectiveness studies in the conjunctiva showed that tobramycin eradicated or controlled 87.8% of the bacterial infections vs. 77.4% for gentamicin. There was also a 9.3% adverse reaction rate with tobramycin vs. 17.6% with gentamicin. Primary symptoms consisted of erythema, injection, discomfort and itching. All adverse reactions were mild and cleared upon discontinuation of the study drug. While the trends seem to favor tobramycin, no difference was statistically significant at the p less than or equal to 0.05 level. These results indicate that tobramycin is a clinically effective and safe topical antibiotic and that it is comparable to gentamicin for topical treatment of bacterial external eye infections. It also may be better tolerated than gentamicin.

A Clinical Comparison of Tobramycin and Gentamicin Sulfate in the Treatment of Ocular Infections

We evaluated the safety and efficacy of tobramycin and gentamicin sulfate ophthalmic solutions in the treatment of patients with bacterial infections of the conjunctivas. In this double-masked study involving 66 patients, the two aminoglycosides were found to be equally safe and effective, although the in vitro data suggested that tobramycin may be more efficacious against Pseudomonas infections. Staphylococcus aureus and S. epidermidis were the most frequent isolates from the infected eyes (59.8% and 20.6%, respectively).

Cataract progression in India

AIMS The study was undertaken to test the feasibility of using the LOCS III cataract grading scale in the field and to determine the rate of cataract progression over a 1 year period of time. METHODS For 150 subjects between the ages of 33 and 55 who attended the refraction clinic at Aravind Eye Hospital in Madurai, India, lens abnormalities were graded at the slit lamp using the LOCS III scale. One year later, 99 of the subjects were re-evaluated by the same methodology to assess the amount of lens change. RESULTS Interrater reliability was high. A change of 0.5 or more in lens colour, cortical, nuclear, or posterior subcapsular cataract was observed in at least one eye of 54% of the subjects. CONCLUSION The LOCS III grading scale is a feasible method for measuring lens changes in the field with the slit lamp. Cataract progression in India is rapid enough to permit intervention studies to be performed with relatively small numbers of subjects over a short period of time (that is, 600 subjects for 2 years).

Antiviral effects of highly purified bacteria-derived human leukocyte interferons (subtypes A and D) and a human fibroblast interferon against herpes virus infection of the rabbit eye

Highly purified preparations of two recombinant-DNA derived human leukocyte interferon subtypes (LeIF-A and LeIF-D) and a similarly derived fibroblast interferon were compared for efficacy against herpes simplex virus, type 1, infection of the rabbit cornea. LeIF-D appeared to be more effective than LeIF-A especially when compared on the basis of interferon units. The fibroblast interferon showed no significant effects. The greater activity of LeIF-D compared with LeIF-A could be due to greater direct antiviral effects, as observed in rabbit cell cultures.