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Biomedical subjects

H R Taylor

Publications and source records attributed to H R Taylor.

At least 127 records · Page 7Linked to original sources
PubMed1997

Reliability of a food frequency questionnaire to assess dietary antioxidant intake.

OBJECTIVE: Epidemiologic evidence of a role for antioxidants in the prevention of chronic disease has been inconclusive, in part due to the difficulty of measuring past diets of free-living populations. The purpose of the current study was to examine the reliability of a 19-item, self-administered, semiquantitative, food frequency questionnaire to assess intake of the major dietary antioxidants. METHODS: Reliability was established by administering the food frequency questionnaire a second time by telephone. The subjects comprised 151 participants in the Melbourne Visual Impairment Project, a study of the distribution and determinants of eye disease in Melbourne residents aged 40 and over. RESULTS: Spearman correlation coefficients ranged from 0.39 for spinach to 0.76 for yoghurt, and all were highly significant (all p = 0.001). The reliability of the instrument was not influenced by gender, English speaking ability, or the number of days between the first and second administration of the questionnaire. CONCLUSION: In conclusion, we have shown this 19-item food frequency questionnaire to be highly reliable. It should be useful for anyone involved in the study of the relationship of dietary antioxidant intake to health outcomes in large populations where limitations of time and money prohibit the collection of more detailed dietary intake information.

Adult↗
PubMed1996

Diabetic retinopathy: examination practices and referral patterns of general practitioners.

OBJECTIVE: To investigate general practitioners' (GPs') examination and referral practices for diabetic retinopathy. METHODS: A questionnaire survey of a random stratified sample of 500 Victorian GPs. RESULTS: The response rate was 88%. 53% of GPs examined none or less than half of their patients with diabetes for diabetic retinopathy. Those who did examine for retinopathy rarely performed funduscopy through a dilated pupil and 65% reported that they never did. Only 37% had dilating drops in their surgery. Only 45% often or always tested visual acuity. 88% often or always referred patients at the recommended frequency to an ophthalmologist. CONCLUSIONS: Although most GPs do not perform dilated fundus examinations, they report referring their patients with diabetes for assessment by an ophthalmologist at an early stage to prevent vision loss. Referral chain breakdown may explain the discrepancy between GPs' reported referral rates and the lower rates of ophthalmic examination reported in the Melbourne Visual Impairment Project.

Clinical Competence↗
PubMed1996

Risk factors for constant, severe trachoma among preschool children in Kongwa, Tanzania.

Trachoma, an ocular infection caused by Chlamydia trachomatis, is the second leading cause of blindness worldwide. The blinding sequelae, which occur in middle age, are felt to be the result of numerous or lengthy episodes of severe inflammatory trachoma in childhood. Risk factors for constant, severe trachoma were identified in a group of children enrolled in a longitudinal study in Kongwa, Tanzania, where villages were randomized in a clinical trial of mass treatment and a behavior modification campaign. In 1989, each of 1,417 randomly selected children had photographs taken of an upper eyelid for determination of their trachoma status. The photographs were graded by a reader who was masked as to the village and date of each photograph. Risk factor data on the family's socioeconomic status, distance to water, and hygiene practices were obtained at baseline. Follow-up examinations occurred 2, 6, and 12 months from baseline. Data from all four time points were available for 82% of the children enrolled. Overall, 10% of the children had constant, severe trachoma, defined as severe trachoma at three or four examinations. The odds ratio for severe trachoma was 1.9 for female children (95% confidence interval 1.3-2.7). Familial cattle ownership and having one or more siblings with trachoma at baseline were also significantly related to the odds of having severe trachoma. Children with a sustainably clean face had lower odds (odds ratio = 0.4, 95% confidence interval 0.3-0.7). A subgroup of 10% of children in these hyperendemic communities always seemed to have severe trachoma, despite enrollment in a mass treatment campaign. Improved face-washing plus antibiotic treatment may decrease the likelihood that these children will be at risk for blinding complications in adulthood.

Animals↗
PubMed1996

Predictability of excimer laser treatment of myopia. Melbourne Excimer Laser Group.

OBJECTIVE: To prospectively examine the predictability of excimer laser photorefractive keratectomy and photoastigmatic refractive keratectomy for myopia that ranged from -1 to -18 diopters (D). METHODS: Patients were treated with an excimer laser and followed up prospectively for 12 months. Low myopia was treated in one ablation zone (6.0 mm), high myopia in two ablation zones (5.0 and 6.0 mm), and extreme myopia in three ablation zones (4.5, 5.0, and 6.0 mm) with a maximum treatment of 15 D. Data were analyzed to determine the distribution of the various postoperative outcomes by preoperative myopia. RESULTS: Two hundred seventy-four low myopes, 189 high myopes, and 41 extreme myopes were available for 12-month follow-up. The re-treatment rate increased with preoperative myopia. The predictability of refraction and uncorrected and best corrected visual acuity progressively decreased with increasing myopia. The likelihood of losing lines of best corrected visual acuity and corneal haze increased with increasing myopia. CONCLUSION: These data should help in the counseling of patients about the likely outcome if they have excimer laser surgery to correct myopia.

Adult↗
PubMed1996

Overcorrection after excimer laser treatment of myopia and myopic astigmatism. Melbourne Excimer Laser Group.

OBJECTIVE: To study the incidence and associations of overcorrection after excimer laser treatment of myopia and myopic astigmatism. METHODS: The study cohort consisted of 645 patients who had photorefractive or photoastigmatic refractive keratectomy done by an excimer laser during a 2-year period. Patients were assessed 1,3,6, and 12 months postoperatively. The variables evaluated were visual acuity, refraction, keratometry, and corneal clarity. RESULTS: At 1 month, overcorrection of more than +1 diopter spherical equivalent (SEQ) was seen in 22% of the eyes. This progressively regressed so that only 8.6% of the 140 eyes that were overcorrected at 1 month were overcorrected at 1 year. Overall, 2.2% of eyes were overcorrected at 1 year. The magnitude of attempted correction and use of topical nonsteroidal anti-inflammatory drugs disclosed a notable association with occurrence of overcorrection at 1, 3, and 6 months. The use of bandage contact lenses also was associated with overcorrection at 1 and 3 months. After controlling for myopia and use of contact lenses, the odds of overcorrection for use of topical nonsteroidal anti-inflammatory drugs at 1,3, and 6 months were 2.21 (95% confidence limits [CL]=1.49, 3.44), 1.69 (95% CL=0.88, 3.24), and 2.01 (95% CL=0.88, 4.56), respectively. The odds of overcorrection with bandage contact lenses were 1.79 (95% CL=1.05, 3.05) at 1 month and 2.42 (95% CL=1.23, 4.75) at the end of 3 months. No associations were seen between overcorrection and age, gender, surgical technique, or simultaneous astigmatic corrections. CONCLUSIONS: Overcorrection is common during the early postlaser treatment period and is associated with degree of myopia, use of nonsteroidal anti-inflammatory drugs, and bandage contact lens wear.

Adult↗
PubMed1996

Retreatment after excimer laser photorefractive keratectomy. The Melbourne Excimer Laser Group.

PURPOSE: To determine the risk factors for undercorrection of myopia after photorefractive keratectomy and to evaluate the efficacy and safety of retreatment. METHODS: A VISX Twenty/Twenty excimer laser was used to treat myopia and myopic astigmatism of up to -15.00 diopters (spherical equivalent) at the corneal plane. Retreatments were performed primarily for undercorrection with or without coexistent corneal haze or abnormalities on videokeratoscopy. Not every patient who was undercorrected requested retreatment. RESULTS: Of 645 eyes (440 patients) followed up for more than 12 months, 58 eyes (9%) required retreatment. The retreatment rate increased with increasing myopia: 17 (5%) eyes with myopia of less than -5.00 diopters, 30 (13%) eyes with myopia of -5.01 to -10.00 diopters, and 11 (19%) eyes with myopia of greater than -10.00 diopters required a second procedure. A higher retreatment rate was observed after astigmatic corrections than after spherical corrections. Corneal haze after retreatment was no greater than that observed after initial procedures. Twelve months after primary procedures, 378 (75%) of 504 eyes were within 1.00 diopter of emmetropia, whereas 27 (69%) of 39 eyes attained this result after retreatment. A total of 383 (76%) of 504 eyes attained uncorrected visual acuity of 20/40 or better after primary procedures, compared with 25 (64%) of 39 eyes after retreatment. CONCLUSIONS: The risk of undercorrection requiring retreatment after photorefractive keratectomy increases with the magnitude of the primary treatment. Although less successful than initial procedures, retreatment appears to enhance the results of photorefractive keratectomy.

Adult↗
PubMed1996

Undercorrection after excimer laser refractive surgery. Excimer Laser Group.

PURPOSE: The incidence and correlations of undercorrection were studied for 1 year after excimer laser surgery for myopia or myuopic astigmatism. METHODS: A consecutive series of 645 eyes of 440 patients were studied. Eyes were examined preoperatively and at 1, 3, 6, and 12 months after surgery. The parameters evaluated were visual acuity, refraction, and corneal clarity. RESULTS: Following excimer laser surgery, undercorrection of > or = -1.00 diopters gradually increased from 10% at 1 month to 40% at 12 months. Increasing degree of preoperative myopia was significantly associated with increasing occurrence of undercorrection at 3 months (chi 2 = 17.3, P < .001), 6 months (chi 2 = 53.6, P < .001), and 12 months (chi 2 = 64.8, P < .001). Undercorrection was more common in eyes that had had photorefractive keratectomy than in those that had had photoastigmatic refractive keratectomy (odds ratio, 0.40; 95% confidence interval, 0.25 to 0.60). At 1 year, a loss of 2 or more lines of best-corrected visual acuity was recorded in 38% of undercorrected patients. Loss of 2 or more lines of best-corrected visual acuity was more common in patients undercorrected by -1.00 diopter or more (odds ratio, 8.8; 95% confidence interval, 5.4 to 14.6). No relationship was seen between corneal haze and loss of best-corrected visual acuity. Undercorrection was not associated with age, gender, use of nonsteroidal anti-inflammatory drugs, bandage contact lens wear, or corneal haze. Patients with lower degrees of myopia reached a stable refraction more quickly. At 6 months, 71% were within +/- 0.5 diopter of 1-year refraction. Of 17 patients with undercorrection who were treated with topical corticosteroids, only one patient showed a permanent beneficial change. CONCLUSION: Occurrence of undercorrection is more common in patients with severe myopia and when simultaneous astigmatic corrections are undertaken.

Adult↗
PubMed1996

Comparison of results of excimer laser correction of all degrees of myopia at 12 months postoperatively. The Melbourne Excimer Laser Group.

UNLABELLED: To examine prospectively the efficacy and safety of photorefractive keratectomy and photoastigmatic refractive keratectomy. METHODS: We treated 645 eyes (440 patients) with a VisX Twenty/Twenty excimer laser and followed them up for 12 months. RESULTS: The percentage of eyes with myopia between -5.01 and -10.00 diopters spherical equivalent within 1 and 2 diopters of emmetropia at 12 months was 65% (123 of 189) and 90% (170 of 189), respectively, whereas the corresponding percentages for eyes with myopia greater than -10.00 diopters spherical equivalent were 39% (16 of 41) and 56% (23 of 41), and for eyes with myopia of -5.00 diopters spherical equivalent or less, 87% (238 of 273) and 99% (270 of 273), respectively. Uncorrected visual acuity of 20/20 and 20/40 or better at 12 months was attained in 47% (129 of 273) and 87% (237 of 273) of the eyes with myopia -5.00 diopters spherical equivalent or less, respectively. At 12 months, 48 (25%) of the 189 eyes with myopia between -5.01 and -10.00 diopters spherical equivalent had uncorrected visual acuity of 6/6 or better and 135 (71%), 6/12. At 12 months, one eye (2%) with myopia greater than -10.00 diopters spherical equivalent had uncorrected visual acuity of 6/6 and 11 (27%) of 41 eyes, 6/12. Ten (4%) of the 273 eyes with myopia of -5.00 diopters spherical equivalent or less, 15 (8%) of the 189 eyes with myopia between -5.01 and -10.00 diopters spherical equivalent, and nine (22%) of the 41 eyes with myopia greater than -10.00 diopters spherical equivalent had lost two or more LogMAR lines of best-corrected visual acuity at 12 months. CONCLUSION: Excimer laser surgery is highly reliable for myopia of -5.00 diopters spherical equivalent or less and is less reliable for greater myopia.

Adult↗
PubMed1996

Topical interferon alpha 2b for corneal haze after excimer laser photorefractive keratectomy. The Melbourne Excimer Laser Group.

PURPOSE: To determine whether topical interferon alpha 2b (IFN-alpha) prevents corneal haze after excimer laser photorefractive keratectomy (PRK). SETTING: Tertiary referral ophthalmic hospital. METHOD: A prospective, double-blind, placebo-controlled, randomized study of 31 patients was undertaken. After surgery in a single institution, patients received a drop of either a placebo or IFN-alpha (5 x 10(6) IU/ml) four times daily for 4 weeks. The main outcome measures were corneal haze, refraction, and visual acuity. RESULTS: The major side effect of interferon alpha treatment was a significant delay in epithelial healing by a mean of 2 days. The means of the average post-treatment clinical scores for haze in all patients up to 12 months after surgery were 0.46 +/- 0.25 for the IFN-alpha group and 0.64 +/- 0.43 for the placebo group (P = .20). Of patients with a correction of greater than 5.00 diopters (D), the IFN-alpha group had significantly less haze over the course of the study (0.39 +/- 0.23 versus 0.98 +/- 0.50; P = .03). After 12 months, the mean absolute spherical equivalent in the two groups was not significantly different (1.02 +/- 1.13 D versus 1.44 +/- 2.64 D). There was a tendency toward better uncorrected visual acuity in the INF-alpha group (P < .10, Kolmogorov-Smirnov). CONCLUSION: Topical IFN-alpha may merit further investigation as a treatment to reduce corneal haze after excimer laser PRK for corrections greater than 5.00 D.

Administration, Topical↗
PubMed1996

Astigmatic change 1 year after excimer laser treatment of myopia and myopic astigmatism. Melbourne Excimer Laser Group.

PURPOSE: To evaluate the surgically induced astigmatism (SIA) 1 year after excimer laser photorefractive astigmatic keratectomy (PARK) and photorefractive keratectomy (PRK). SETTING: Royal Victorian Ear and Eye Hospital, Melbourne, Australia. METHODS: This study comprised 333 PARK patients and 155 PRK patients treated with a VISX 20/20 excimer laser and followed prospectively for 12 months. Vector analysis of the change in astigmatism was used to calculate the SIA in the PRK group and the percentage of astigmatism corrected in the PARK group. RESULTS: Among patients with low cylinders astigmatic correction varied greatly, particularly in those treated for large amounts of myopia. The spherical PRK treatments yielded a mean induced postoperative astigmatism of 0.47 diopter. There was a linear relationship between this inadvertent SIA and increasing myopia. CONCLUSION: Excimer laser surgery for myopia creates a low degree of random, unpredictable SIA that may be the result of irregular epithelial thickening during postoperative healing. This creates a background noise of astigmatic change upon which the targeted astigmatic correction is superimposed.

Adult↗
PubMed1996

Referral to low vision services by ophthalmologists.

PURPOSE: People in need of low vision rehabilitation services often experience delays in referral to services. This study investigates referral criteria of Australian ophthalmologists, the frequency of referral of their patients with low vision and their perceptions of low vision services. METHODS: A survey was sent to a representative, random sample of 200 ophthalmologists. They were asked about criteria used for the referral of their patients with low vision. The survey included questions on the frequency with which they prescribed low vision devices (LVD) and referral of their patients to low vision and rehabilitation services and peer support groups. Perceptions of the quality and availability of low vision services were also investigated. RESULTS: The response rate was 82%. Approximately 11% of ophthalmologists' patients have low vision. It is uncommon for ophthalmologists to prescribe LVD but 67% refer most of their patients with low vision. It is less common for them to refer to rehabilitation services (29%) or peer support services (18%). The perceived local availability of services influences the rate of referral. Ophthalmologists who used the criteria of moderate low vision (< 6/21 to < 6/60) are more likely to refer more of their patients than those who use the criteria of severe low vision. CONCLUSIONS: Australian ophthalmologists refer most of their visually impaired patients to low vision services, but infrequently to rehabilitation services or peer support groups. Differences in perceived need for low vision services indicated by the criteria used for referral, and the perceived availability, influence the rate at which ophthalmologists refer their patients for services. Ophthalmologists are encouraged to refer patients with permanent visual loss to low vision services earlier.

Australia↗
PubMed1996

Relation of hormone and menopausal status to outcomes following excimer laser photorefractive keratectomy in women. Melbourne Excimer Laser Group.

PURPOSE: To examine the effect of hormone use, pregnancy and menopausal status on clinical outcomes following excimer laser surgery for myopia and myopic astigmatism. METHODS: Participants comprised all female patients of the Melbourne Excimer Laser Group (MELG). A standardised surgical protocol was followed by the 27 MELG members, using the VisX 20/20 excimer laser and included the prospective collection of the following information preoperatively and one, three, six and 12 months after the procedure: uncorrected and best corrected visual acuity with a LogMAR chart; best manifest refraction; and subjective assessment of corneal clarity. A survey that elicited information about oral contraceptive (OC) use, pregnancy history, surgical and natural menopause, and use of hormone replacement therapy (HRT) was mailed to all the women. RESULTS: A 77% response to the mailed survey was achieved. Two women were pregnant at the time of surgery, one became pregnant during the first month after surgery, and all three women were excluded from further analyses, although a review of two of the case histories revealed suboptimal clinical outcomes. Women taking OC were included in the control group after OC use was shown not to be associated with outcome. Women were grouped accordingly: control, n = 225, pre-menopausal on HRT, n = 7, post-menopausal not on HRT, n = 34; and post-menopausal on HRT, n = 21. The groups differed significantly with regard to age and preoperative spherical equivalent. After controlling for age and preoperative spherical equivalent, the mean number of uncorrected LogMAR letters read one year after surgery was significantly lower for the post-menopausal women on the HRT in comparison with the control group. Best corrected acuity and corneal clarity were not significantly different among the groups. DISCUSSION: These preliminary results suggest that the interaction of menopausal and HRT status could decrease the effectiveness of PRK and PARK, but require confirmation with a further study in a prospective manner using objective measures of corneal epithelial healing and serum hormone levels.

Adult↗
PubMed1996

Cataract surgery in Australia 1985-94.

BACKGROUND: Cataract surgery is the most common form of major ophthalmic surgery in Australia and a common surgical procedure among the elderly. The purpose of this report is to compile the numbers and rates of cataract extractions and implant of IOLs over the period 1985-94 for Australia. METHODS: Data were obtained for public and private cataract extractions and IOL implants from state and territory ministries of health and from the Health Insurance Commission. The data relating to cataract surgery were compared with the growth in the proportion of elderly people in the population. RESULTS: The number of cataract extractions has increased by 2.6 times over the ten-year period to 67,459 in 1994 and IOL implants have increased by 2.9 times over the same period to 70,084. The increase in the elderly population for the period was 1.3 times so that there is a relative doubling in the rate of surgery. The proportion of public patients has risen from 19% to 28% from 1985 to 1994. CONCLUSIONS: The numbers of cataract extractions and IOL implants was increased at double the rate expected from the growth in the elderly population. Advances in microsurgery and IOL technology have resulted improved outcomes and have created a greater patient demand. The improved outcomes have also lead to ophthalmologists recommending cataract surgery at better visual acuity levels than previously.

Aged↗
PubMed1996

Association of keratoconus with granular corneal dystrophy.

A 23-year-old woman presented with a history of reduced vision and foreign body sensation in both her eyes. Ocular examination revealed the simultaneous presence of bilateral keratoconus and granular corneal dystrophy. To our knowledge, bilateral concurrent occurrence of keratoconus and typical granular corneal dystrophy has not been reported previously. In such a case, penetrating keratoplasty performed for keratoconus may also carry the risk of recurrence of the granular dystrophy.

Adult↗
PubMed1996

Prevalence and risk factors for trachoma in Sarlahi district, Nepal.

AIMS: To estimate the prevalence of trachoma in preschool children in Sarlahi district, Nepal, and to identify risk factors for the disease. METHODS: A stratified random sample of 40 wards was selected for participation in a trachoma survey. Within each ward, a systematic 20% sample of children 24-76 months of age was chosen to determine the presence and severity of trachoma using the World Health Organisation grading system. RESULTS: A total of 891 children were selected and 836 (93.8%) were examined for trachoma from December 1990 to March 1991. The prevalence of active trachoma was 23.6% (21.9% follicular and 1.7% intense inflammatory). Cicatricial trachoma was not seen in this age group. The prevalence of trachoma ranged from 0 to 50% across wards with certain communities at much higher risk for trachoma than others. Three year old children had the highest prevalence of follicular (25.5%) and intense inflammatory trachoma (4.3%). Males and females had similar prevalence rates. Wards without any tube wells were at higher risk than those with one or more tube wells. Lower rates of trachoma were seen in families who lived in cement houses, had fewer people per room, more servants, more household goods, animals, and land. Hence, less access to water, crowding and lower socioeconomic status were risk factors for trachoma. CONCLUSIONS: Although follicular trachoma is prevalent, intense inflammatory trachoma is relatively rare and scarring was not observed in this preschool population. Hence, this population may not be at high risk for repeat infections leading to blindness in adulthood.

Child↗