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Biomedical subjects

Thomas Naduvilath

Publications and source records attributed to Thomas Naduvilath.

9 recordsLinked to original sources
PubMed2006

Awareness and use of eye care services in Fiji.

PURPOSE: To determine the awareness, use, and barriers to use of eye services in Fiji's Central Province. METHODS: A cross-sectional survey study design with random clusters of households was used. Semi-structured interviews were conducted (152 females and 22 males). For 267 household members, presenting distance and near visual acuities were measured, and the perception of and satisfaction with their vision were recorded. RESULTS: Most (86%; 150/174) respondents were aware of at least one conventional eye care service. However, only 66% (121/183) of household members with previous eye problems had consulted one of these; the proportion was even lower for those in the older age groups (p < 0.01). Rural dwellers expressed satisfaction with their vision, despite being more likely to regard it as limiting their activities and being less likely to seek conventional care. A higher proportion of females were reported to have (or have had) eye problems (60:40) and were found to have bilateral visual impairment (60:40). Despite this, females and males attended the hospital eye clinic (47:53) or sought treatment from conventional services (51:49) nearly equally. The reasons given for not seeking conventional care were "fatalistic attitude" ("did not bother", "could manage", or accepted the condition: 57%), expense (12%), and fear (8%). CONCLUSION: Central Province Fijians, particularly the old, rural, and female, under-utilise conventional eye care services. As in developing countries elsewhere, fatalistic attitudes to visual impairment are a significant contributor to this. To improve eye health, planning and implementation of eye care services must overcome under-utilisation by addressing local barriers to uptake through community participation in education and affirmative action.

Adolescent↗
PubMed2006

Cataract and its surgery in Timor-Leste.

PURPOSE: To determine the prevalence of visually significant and unoperated blinding cataract, and the coverage, characteristics and outcome of cataract surgery in Timor-Leste. METHODS: Based on the World Health Organization Rapid Assessment of Cataract Surgical Services protocol, a population-based cross-sectional survey was conducted in 2005. By two-stage cluster random sampling, 50 clusters of 30 people aged 40 years and older were selected. Each eye with a presenting visual acuity worse than 6/18 and/or a history of cataract surgery was examined. RESULTS: Of the 1470 people enumerated, 96.2% were examined. Of the eyes examined, 11.5% were blind (presenting vision less than 6/60). Cataract caused 66.3% of this, and 40.2% of vision impairment (presenting vision less than 6/18). For those people who were blind (7.7%; presenting vision less than 6/60 in the better eye), cataract was the most frequent cause (76.1%). Cataract surgery had occurred in 2% of participants. Gender and domicile were not associated with cataract blindness or surgery. Cataract Surgical Coverage (6/60) was 16.3% for Eyes and 20.2% for Persons. Surgical outcomes were poor, falling well short of World Health Organization guidelines. Astigmatism and posterior capsule opacity were important contributors to this. CONCLUSIONS: Until census data are available, age-gender-domicile correction of sample findings cannot be calculated. In the meantime, it is estimated there are 11 500 cataract blind in Timor-Leste. Long-term, indigenous cataract surgical services need to be capable of significantly increased output. Better surgical outcomes are required to ensure scarce resources are well used. Laser capsulotomy needs to be planned for as surgical numbers increase.

Adult↗
PubMed2006

Accommodative facility in eyes with and without myopia.

PURPOSE: To compare accommodative facility in eyes with myopia to that in eyes with emmetropia or hyperopia and to determine whether accommodative facility can be used to predict an association with myopia. METHODS: In the Sydney Myopia Study, year-1 school children (6.7 +/- 0.4 years) were assessed for accommodative facility at distance (3 m) and near (33 cm) with semiautomated flippers. Spherical equivalent refractive error (RE) was defined as myopia (< or = -0.50 D), emmetropia (> -0.50 D, but < +1.50 D), and hyperopia (> or = +1.50 D) based on postcycloplegia readings. Only right eye data were considered. Differences between groups were analyzed with the Brown-Forsythe F test after adjustment for age and gender. Multiple comparisons were adjusted with the by the Games-Howell METHOD RESULTS: Of the 1328 right eyes assessed, 20 (1.5%) eyes were myopic, 977 (73.6%) were emmetropic, and 331 (24.9%) were hyperopic. At distance, mean facility was less for myopic eyes at 5.5 +/- 2.0 cycles per minute (cpm) in comparison to 6.9 +/- 1.7 cpm for eyes with emmetropia or hyperopia (P = 0.005). Myopic eyes recorded greater positive and negative accommodative response times than did emmetropic or hyperopic eyes (P < 0.05). There were no differences among the groups in near facility. The area under the receiver operating characteristic (ROC) curve for distance facility was 0.692 (P = 0.003, 95% CI, 0.580-0.805). CONCLUSIONS: Myopic eyes have reduced accommodative facility at distance, and accommodative responsiveness to both positive and negative defocus is slow. However, accommodative facility as a test does not have sufficient power to discriminate eyes with myopia from other refractive errors.

Accommodation, Ocular↗
PubMed2006

Factors affecting the morbidity of contact lens-related microbial keratitis: a population study.

PURPOSE: To examine factors influencing the severity of soft contact lens (SCL)-related microbial keratitis. METHODS: Cases were detected via surveillance studies in Australia and New Zealand. Factors affecting disease severity (costs, days of symptoms, and 2 or more lines of vision loss) were examined and included age; gender; delay in SCL removal, seeking consultation, or receiving treatment; overnight wear; SCL material (hydrogel or silicone hydrogel [SiH]); and causative organism. RESULTS: Two hundred ninety-seven cases were identified: 61% female, age: 35 +/- 13 years (mean +/- SD). Treatment costs were (median [interquartile range]) $760 [1859] and indirect costs were $468 [1810]. Patients were symptomatic for 7 [11] days, and vision loss occurred in 14.3% of cases. Cases with pathogenic causative organisms (66/297, 22%) were 11.4 times (95% confidence interval [CI], 4.2-30.9) more likely to result in vision loss, had longer duration of symptoms (21 [40] vs. 6 [8] days, P < 0.001) and incurred higher costs (5,512 [14,733] vs. 1,048[8,325], P < 0.001). Delays (>12 hours) before treatment increased the likelihood of vision loss (P = 0.048) disease duration (P = 0.004), and associated costs (P = 0.009). Remoteness increased the risk of vision loss (odds ratio [OR] = 5.1; 95% CI 1.6-16.6), and individuals over 28 years of age had longer disease duration (P = 0.02). In overnight wear and after adjustment for culture result and treatment delays, SiH wearers had slightly shorter disease duration (4 [4] vs. 7 [10] days, P = 0.02) but a rate of vision loss and cost similar to those of hydrogel wearers. CONCLUSIONS: The causative organism was the major determinant of severity; however, modifiable factors such as delays in treatment had considerable influence. Duration of symptoms was shorter in SiH wearers, but other factors dominated disease outcome in this population study.

Adolescent↗
PubMed2005

Microbial keratitis predisposing factors and morbidity.

PURPOSE: To examine predisposing factors, treatment costs, and visual outcome of microbial keratitis in an ophthalmic casualty and inpatient population. DESIGN: Retrospective medical records review. PARTICIPANTS: Fifteen- to 64-year-olds with microbial keratitis treated at the Royal Victorian Eye and Ear Hospital between May 2001 and April 2003 (n = 291). METHODS: Risk factors were identified from patient files. Demographic, clinical, and microbiological data; severity; outpatient visits; hospital bed days; and vision loss were examined. MAIN OUTCOME MEASURES: Cost to treat (Australian dollars), vision loss, and factors influencing these outcomes. RESULTS: Ocular trauma (106/291 [36.4%]) and contact lens (CL) wear (98/291 [33.7%]) were the most commonly identified predisposing factors; 18 (6.1%) had multiple predisposing factors; 17 (5.8%), ocular surface disease; 20 (6.9%), herpetic eye disease; 4 (1.4%), systemic associations; 5 (1.7%), other; and 23 (7.9%), unknown cause. Of trauma cases, 90.6% involved males, compared with 44% to 57% for other groups (P<0.001). Contact lens wearers were younger than the other groups--mean age 30 years, compared with 40 to 47 years (P<0.01). Gram-negative organisms were isolated more frequently in CL wearers than trauma cases (18.7% vs. 6.5%, P = 0.01). The number of outpatient visits was 4+/-1 (median +/- interquartile range), and 19.6% (57/291) were hospitalized for 5+/-2 days. Hospital resource use and vision loss were similar for predisposing factors but differed by causative microorganism. Eighty-eight percent of cases were scraped: acanthamoeba keratitis was the most expensive to treat, followed by fungal and herpetic keratitis and, lastly, culture-proven bacterial keratitis or culture-negative cases (P<0.0001). After treatment, 21.7% exhibited >2 lines of vision loss, and 1.6% of cases had > or =10 lines of vision loss. Vision loss was associated with clinical severity (P = 0.005). CONCLUSIONS: Ocular trauma and CL wear are the major predisposing factors for microbial keratitis in this age range. These cases require significant hospital resources during treatment, and the keratitis may result in loss of vision.

Acanthamoeba Keratitis↗
PubMed2004

Changes in myopia with low-Dk hydrogel and high-Dk silicone hydrogel extended wear.

PURPOSE: This study compared changes in myopia between wearers of high-oxygen permeability (Dk) silicone hydrogel lenses and low-Dk hydrogel lenses after 1 year of extended wear (EW). METHODS: Ninety-two adult subjects were randomly assigned to a lens type. Subjective refraction and autokeratometry were performed at baseline and at 6 and 12 months. RESULTS: After 6 months of EW, myopia (spherical equivalent) regressed by 0.18 +/- 0.33 D (p < 0.001) in the high-Dk silicone hydrogel group and progressed by -0.23 +/- 0.36 D (p < 0.001) in the low-Dk hydrogel group. There were no further changes after 12 months. Previous lens wear history, baseline refractive error, and age and gender did not have an impact on the change in myopia, and only 35% of the variation could be accounted for by changes in corneal curvature and lens type. CONCLUSION: Soft contact lens type significantly affects the direction of change in myopia during EW. We hypothesize that these changes are driven by pressure-related redistribution of corneal tissue in high-Dk silicone hydrogel lens wearers and by hypoxia-associated corneal thinning in low-Dk hydrogel wearers. More long-term studies are required to confirm whether the effects of high-Dk silicone hydrogel lens wear on myopia are permanent.

Adult↗
PubMed2004

Evaluation of surveillance methods for an epidemiological study of contact lens related microbial keratitis.

PURPOSE: To evaluate surveillance methods in a pilot epidemiological study of contact lens related microbial keratitis (MK) cases identified by ophthalmic practitioners in Australia and New Zealand between May and August 2003 inclusive. METHODS: Twelve ophthalmologists and 55 optometrists from rural and metropolitan locations were sent a study information pack with postal reporting forms. After 2 months, practitioners were emailed a link to a website for Internet reporting. After 4 months, practitioners were prompted by email and then by telephone if a response was not received. Passive response rates were the rate of returns after posting information and emailing the website link. Active response rates included personalized email and telephone follow-up. RESULTS: Ten cases of MK were identified by optometrists and five by ophthalmologists. The passive response rates were 79% and 58% for the first and second reporting periods, respectively. There was a lower response rate in the second reporting period compared to the first (P = 0.02). With active surveillance the response rate increased to 97% and 96%. A large proportion of optometrists (62%) and ophthalmologists (55%) used the website for at least one reporting period. Internet reporting was used by all New Zealand practitioners (5/5). CONCLUSIONS: A surveillance study to estimate the incidence of contact lens related MK in Australia and New Zealand is feasible and acceptable. Internet-based reporting offers a reliable, rapid and cost-effective means of running a large scale, international surveillance study. Active surveillance methods are necessary to enhance reporting rates.

Adolescent↗
PubMed2003

Comparison of adverse events with daily disposable hydrogels and spectacle wear: results from a 12-month prospective clinical trial.

OBJECTIVE: To evaluate the type and incidence of adverse events seen with daily disposable hydrogel contact lens wear compared with a control (spectacle) group over 12 months. DESIGN: Prospective, randomized, observer-masked, comparative clinical trial. PARTICIPANTS: Two hundred eighty-one myopes with no prior contact lens wear experience were enrolled from August to December 1996. Subjects were 16 to 35 years old and had refractive errors ranging from a -0.75-diopter (D) sphere to a -6.00-D sphere with a cylinder less than -1.00 D. INTERVENTION: Each subject was randomly assigned to wear either bilateral disposable hydrogels on a daily disposable wear schedule or spectacles. MAIN OUTCOME MEASURE: Type and incidence of adverse events from each group. Adverse events were categorized as serious, significant, and nonsignificant based on the potential to cause vision impairment, severity at event, and level of clinical concern. RESULTS: At baseline, 1.6% of eyes had asymptomatic infiltrates that were nonsignificant. During the study, asymptomatic infiltrates were seen in both contact lens and spectacle groups at 20.5 events versus 11.3 events per 100 eyes per year of wear. No significant events were seen with the spectacle group. With the contact lens group, the type and incidence of significant events per 100 eyes per year of lens wear were corneal peripheral ulcer, 2.5 events; infiltrative keratitis, 1.5 events; and papillary conjunctivitis, 1 event. The incidence of both significant and nonsignificant events was greater with the contact lens group (P<0.05). No serious events (i.e., microbial keratitis) were seen in either group. A greater number of subjects were lost to follow-up or permanently discontinued from the contact lens group relative to the spectacle group (33% vs. 17%, P = 0.002). Lens-related problems such as dryness, discomfort, and difficulty with insertion and removal accounted for 27% of discontinuations from the contact lens group. Poor compliance (40%) was the greatest reason for discontinuations from the spectacle group. CONCLUSIONS: No clinically serious events were seen with either group. Only a small percentage of contact lens-wearing eyes presented with significant events, which is promising for daily disposable lens wear. Far more contact lens subjects were lost to follow-up or discontinued. Small, asymptomatic, subepithelial corneal infiltrates of unknown significance were seen in both contact lens- and spectacle-wearing eyes.

Adolescent↗