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).

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 of Acanthamoeba. 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 Fusarium spp, 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 pneumoniae accounting for the majority of bacterial ulcers and Fusarium spp 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.

Incidence of corneal ulceration in Madurai district, South India.

OBJECTIVE: To determine the incidence of corneal ulceration in Madurai District, South India. DESIGN: Retrospective incidence study. SETTING: General community. PATIENTS: All patients who reside in Madurai District and presented to an ophthalmologist in 1993 with corneal ulceration. MAIN OUTCOME MEASURE: Cases of corneal ulceration. RESULTS: 1148 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. CONCLUSION: Corneal 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.

Antibiotic supplementation of intraocular irrigating solutions. An in vitro model of antibacterial action.

PURPOSE: The 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. METHODS: Clinical 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. RESULTS: Most 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. CONCLUSIONS: Exposure 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.

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.

Cellular response to inflammation at the limbus.

The role in ocular (limbal) inflammation of the rich vascular and lymphatic supply is discussed in detail. The distribution of lymphocytes, mast cells, Langerhans cells, macrophages and other cellular elements are discussed as well as their individual and collective response to inflammation whether due to infectious or non-infectious disease states. Among the non-infectious causes of limbal cellular inflammation are the four types of hypersensitivity response.

Use of recombinant interferon in HSV-1 recurrence in the rabbit.

The use of recombinant human interferon alpha subtype D (RIFN alpha D) was effective in reducing shedding of herpes simplex virus type-1 induced by iontophoresis of 6-hydroxydopamine and epinephrine. A post stimulation treatment schedule of RIFN alpha D, one drop four times a day was as effective as pretreatment, using the same dose regimen. The levels of interferon (IFN) present in the assay system are not sufficient to produce an antiviral effect. The levels of IFN required to suppress cell growth are substantially higher than the concentrations detected in the assay system.

Interferon effects on herpes simplex virus in rabbit and human cell cultures.

The effects of four subtypes of recombinant human alpha interferon (RIFN alpha), (A,B,D, and the hybrid A/D) were tested on six strains of herpes simplex virus (HSV). RIFN alpha -D was the most effective subtype in rabbit kidney cells, which is consistent with our previous in vivo results in the rabbit herpetic keratitis model. In human corneal cells, however, RIFN alpha -D was one of the least effective IFN subtypes tested. Conversely, RIFN alpha-A appeared to be relatively more effective in the human corneal cells than in the rabbit kidney cells, but RIFN alpha -B and RIFN alpha -A/D were the most effective interferon subtypes in human corneal cells. Different strains of HSV had different susceptibilities to the various IFN subtypes tested.

Trimethoprim-polymyxin B ophthalmic solution in treatment of surface ocular bacterial infections.

A safety and efficacy study comparing the clinical and bacteriologic effectiveness of trimethoprim-sulfacetamide-polymyxin B-neomycin-gramicidin in a group of patients with surface ocular bacterial infections was conducted. The results demonstrated TSP to be as effective as the other solution (both clinically and bacteriologically), with fewer adverse experiences. A second study was conducted comparing TSP with trimethoprim-polymyxin B (TP) and found TP to be superior to TSP in effecting bacteriologic cures. Clinical response was similar in both groups, and the low incidence of mild adverse experiences was approximately the same. It appears that the combination of trimethoprim with polymyxin B is safe and highly efficacious, both clinically and microbiologically, for the treatment of surface ocular bacterial infections.

Recombinant human interferon alpha D in HSV-1 recurrence in the rabbit.

Recombinant human interferon alpha subtype D (RIFN alpha D) was effective in reducing the shedding of herpes simplex virus type-1 (HSV-1) induced by 6-hydroxydopamine iontophoresis followed by topical epinephrine application in previously infected rabbit corneas. A treatment schedule of RIFN alpha D, two drops QID was superior to one drop BID. RIFN alpha A also appeared to be effective in reducing viral shedding. Rabbits treated with RIFN alpha D during two episodes of adrenergically induced HSV-1 shedding, but not during anticipated episodes of spontaneous shedding, did not show a significant reduction in shedding of virus. Interferon was present in significantly higher concentration in tear samples following treatment with RIFN alpha D as compared with RIFN alpha A.

Use of recombinant interferon to prevent recurrent herpesvirus shedding.

Iontophoresis with 6-hydroxydopamine was performed in rabbits previously infected with herpes simplex virus, McKrae strain. Viral shedding into the tear film was significantly decreased by the use of recombinant alpha interferon subtype D given as one drop qid. Interferon was noted in the tear film of rabbits 16-18 hours after the last placement of interferon drops into the inferior cul-de-sac.