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Biomedical subjects

P Courtright

Publications and source records attributed to P Courtright.

At least 37 records · Page 2Linked to original sources
PubMed2001

Reduction of trachoma in the absence of antibiotic treatment: evidence from a population-based survey in Malawi.

PURPOSE: A survey was conducted in Chikwawa District, Malawi in order to compare the current prevalence of trachoma with a similar survey in 1983. METHODS: Using random cluster household sampling, children aged 1 to 6 and adults aged 50 or older were enumerated and examined for the presence of trachoma. RESULTS: Among the 1313 children enumerated, 1249 (95.1%) were examined and among the 1431 adults enumerated, 1221 (85.3%) were examined. The prevalence of active trachoma among the children was 13.9% (11.9-15.9%), 10.0% in males and 14.4% in females. The prevalence of active trachoma varied significantly among the 25 clusters, ranging from 3.9% to 38.2% with 5 clusters (20%) having a prevalence >20%. Signs of trachomatous trichiasis were observed in 1.0% of adults examined. Active disease in 1999 was associated with a longer distance to the primary water source. CONCLUSIONS: Since 1983 there has been no mass antibiotic treatment programme in the district and little change in socioeconomic status. However, compared to the 1983 findings, active trachoma has been reduced by over 50% (p < 0.001) and trachomatous trichiasis by over 80%. In the 16-year interim (especially in the past 7 years) health, water and hygiene programmes were initiated and we hypothesize that the reduction in active disease is likely due to these changes. Our findings suggest that sustained reductions in active trachoma can be achieved without community-based antibiotic distribution.

Age Distribution↗
PubMed2001

Recurrence of trichiasis: a long-term follow-up study in the Sultanate of Oman.

BACKGROUND: The prevalence of long-term trichiasis recurrence following tarsal rotation and electro-epilation procedures has not been determined. A non-concurrent prospective study of surgical cases of trichiasis was therefore undertaken in Oman. METHODS: A sample of 603 surgical cases of trichiasis (approximately half tarsal rotation and half electro-epilation) was followed for an average of 3.1 years to determine recurrence. Recurrence was defined as either mild (<5 lashes touching the globe) or severe (5 or more lashes touching the globe). RESULTS: Overall, 56% (95% confidence interval of 50.6%-61.0%) of all surgical cases recurred; ranging from 61.8% of tarsal rotation patients to 50.6% of electro-epilation patients. Severe recurrence was detected among 27% of tarsal rotation patients and 10% of electro-epilation patients. Recurrence was associated with female sex, residence in a high-risk region, and time since surgery. DISCUSSION: The risk of recurrence after electro-epilation and bilamellar tarsal rotation surgery is high; strategies that account for recurrence need to be introduced.

Adult↗
PubMed2001

Reliability and reproducibility of a Chinese-language visual function assessment.

OBJECTIVE: The purpose of the study was to validate a Chinese-language visual function assessment within the context of a routine cataract surgery practice and to assess the contribution of the method of questionnaire administration. DESIGN: The visual function assessment (VFA) was translated into Chinese. Two groups of study subjects were recruited: Chinese who did not speak English and Chinese conversant in English. Consecutive preoperative cataract patients of Chinese ancestry presenting to an urban ophthalmology practice were recruited. The questionnaire was administered in person or by telephone interview. Pre-operative visual acuity was recorded. Visual function scores were analyzed to assess reliability and correlation with visual acuity. RESULTS: Among the 186 potential study subjects, 155 patients completed the study The Chinese-language visual function assessment had good internal consistency (Cronbach alpha = 0.97, inter-item correlations = 0.43 to 0.96) . Reliability (with regard to the English version) and test-retest reproducibility of the Chinese questionnaire were strong with intraclass correlation coefficients greater than 0.60. The method of administration contributed to the measures of reliability and reproducibility. CONCLUSION: These results show that a Chinese-language version of the VFA questionnaire is reliable and valid. In industrialized countries with large Chinese-speaking populations and newly developed countries of East and Southeast Asia, the visual function assessment may be helpful in assisting routine clinical patient evaluation and cross-cultural outcome assessment programmes. Our findings also suggest that self-administered visual function assessments may be more reliable and valid than interview-generated assessments.

Aged↗
PubMed2001

The burden of trachoma in the rural Nile Delta of Egypt: a survey of Menofiya governorate.

BACKGROUND: Evidence of widespread distribution of trachoma in Egypt had not been clarified as previous surveys were limited to individual communities which may not have been representative of the general population. The Nile Delta of Egypt presents a unique environment for trachoma to persist. Economic improvements in the past decade have affected even the poorest rural environments; availability of electricity is now found in many rural communities. Availability of water in Nile Delta has always been good but poor hygienic conditions have been the primary factor in trachoma transmission. A survey of trachoma was undertaken in Menofiya governorate to determine if Egypt should be identified as trachoma endemic and targeted for trachoma control efforts. METHODS: A multistage random cluster study design was used with the target population defined as adults aged 50 and over and children aged 2-6 years from throughout the governorate. Among preschool children only trachoma was graded while among adults presenting visual acuity and cause of vision loss or blindness were also recorded. Adults were interviewed regarding past trichiasis surgery; those currently with trichiasis or a history of trichiasis surgery were also interviewed regarding outcome of surgery. RESULTS: A total of 3272 children aged 2-6 and 3322 adults age 50+ were enumerated. Among the children 81.3% were examined and among the adults 73.0% were examined. Active trachoma (follicles (TF) and/or intense inflammation (TI)) was found among 36.5% (95% confidence interval (CI) 34.7-38.3%) of the children. TI was 1.89 (95% CI 1.22-2.94) times more common in rural children compared to urban children. The prevalence of trichiasis (TT) in adults was 6.5%; women had an age adjusted odds of trichiasis of 1.68 (95% CI 1.18-2.39) compared to men. Trichiasis was 2.11 times (95% CI 1.33-3.37) more common in rural Menofiya compared to urban Menofiya. TT accounts for blindness (presenting vision <3/60) in 8% of patients and accounts for 13.2% of visual impairment. Overall, trichiasis surgical coverage was 34.4%, slightly higher among men than women. The outcome of trichiasis surgery was poor in 44.4% of cases. CONCLUSION: Trachoma is a serious public health problem in Menofiya governorate and a significant contributor to vision loss. These findings would suggest that continued poor hygienic conditions in rural Egypt have limited the reduction of active trachoma even in the face of significant improvements in socioeconomic status. Furthermore, the high proportion of trichiasis surgery cases with a poor outcome would indicate a need to reassess current surgical practices in Egypt and improve training and monitoring.

Aged↗
PubMed2001

Cataract in leprosy patients: cataract surgical coverage, barriers to acceptance of surgery, and outcome of surgery in a population based survey in Korea.

BACKGROUND/AIMS: Cataract is the leading cause of blindness in leprosy patients. There is no population based information on the cataract surgical coverage, barriers to use of surgical services, and outcome of surgery in these patients. We sought to determine these measures of cataract programme effectiveness in a cured leprosy population in South Korea. METHODS: The population consisted of residents of six leprosy resettlement villages in central South Korea. All residents were invited to participate in a study of eye disease and interviewed regarding use of surgical services and reasons for not using these services. RESULTS: The cataract surgical coverage in this population was 55.4% when <6/18 was used as the cut off and increased to 78.3% when the cut off was <6/60. Barriers reported by patients included being told by the doctor that the cataract was not mature and a perception by the patient that there was no need for surgery. Among patients who had aphakic surgery, 71% were still blind in the operative eye while among patients who had pseudophakic surgery, 14% were still blind (presenting vision). Blindness in pseudophakic patients could be reduced to 3% with spectacle correction. CONCLUSION: Cataract prevalence in leprosy patients will increase as life expectancy continues to increase. Leprosy control programmes will need to develop activities aimed at reducing the burden of cataract. Recommendations include establishing collaborative agreements with ophthalmological services to provide high quality IOL surgery to these patients, training of health staff to identify and refer patients in need of surgery, monitoring the uptake of cataract surgery among patients needing services, and monitoring the outcome of surgery to improve refractive outcome.

Aged↗
PubMed2001

Blindness in Africa: present situation and future needs.

AIM: To review the prevalence and causes of blindness in sub-Saharan Africa, the existing services and limitations, and the Vision 2020 goals for the future. METHODS: Methodologically sound population based surveys published in the past 20 years are reviewed and results for prevalence and causes of blindness are tabulated. The current resources and needs according to recent publications and international working groups are described. CONCLUSIONS: Blindness prevalence rates vary widely but the evidence suggests that approximately 1% of Africans are blind. The major cause is cataract; trachoma and glaucoma are also important causes of blindness. The bulk of blindness in the region is preventable or curable. Efforts should focus on eye problems which are universally present and for which there are cost effective remedies, such as cataract and refractive problems and on those problems which occur focally and can be prevented by primary healthcare measures, such as trachoma, onchocerciasis, and vitamin A deficiency. Major development of staffing levels, infrastructure, and community programmes will be necessary to achieve Vision 2020 goals.

AIDS-Related Opportunistic Infections↗
PubMed2001

Lagophthalmos surgery in leprosy: findings from a population-based survey in Korea.

Lagophthalmos continues to be a serious problem in cured leprosy patients. We conducted a population-based survey of lagophthalmos surgical coverage (LSC), barriers to lagophthalmos surgery and outcome of lagophthalmos surgery in leprosy patients in South Korea. In our survey, there were 60 patients with lagophthalmos who had needed surgery (> 5 mm gap), 34 of whom had received surgery, resulting in a lagophthalmos surgery coverage of 57%. Among the 34 patients who had received lagophthalmos surgery, 18 needed further surgery. Among those who had never had surgery, none of the demographic indicators predicted surgical uptake; the primary reason given for failure to have surgery was lack of knowledge about it. Outcome of surgery (by eye) showed that 29% of eyes still had a gap of 5 mm or more. The frequency of symptoms (tearing, blurring of vision, pain, etc.) was high. Even in settings with a good eye care infrastructure, such as Korea, uptake of surgery can still be low and results may not be satisfactory to patients. There is a need for practical guidelines for leprosy control programmes in the areas of (a) patient recognition, (b) patient education, (c) monitoring the uptake of surgery, and (d) monitoring the outcome of surgery to ensure the best possible outcome.

Adult↗
PubMed2000

Progression of eye disease in "cured" leprosy patients: implications for understanding the pathophysiology of ocular disease and for addressing eyecare needs.

BACKGROUND: Ocular damage in leprosy is due either to nerve damage or infiltration by mycobacteria. There is currently little information about the magnitude and nature of incident ocular pathology in cured leprosy patients. This information would increase our understanding of the pathophysiology of ocular involvement in leprosy and help in developing programmes to address the eyecare needs of leprosy patients who have been released from treatment. The cumulative incidence of leprosy related ocular pathology and cataract was measured during an 11 year follow up period in cured leprosy patients released from treatment in Korea. METHODS: In 1988 standardised eye examinations were performed on 501 patients in eight resettlement villages in central South Korea. In May 1999 standardised eye examinations were repeated in this population. RESULTS: Among the patients in whom there was no sight threatening leprosy related ocular disease (lagophthalmos, posterior synechia, or keratitis) in 1988, 14.7% developed one or more of these conditions. Overall, among those with no vision reducing cataract in 1988, 26.4% had developed a vision reducing lens opacity in at least one eye. Among patients examined in both 1988 and 1999, 14.3% developed visual impairment and 5.7% developed blindness. CONCLUSION: This study demonstrates that leprosy related ocular pathology progresses in some patients even after they are cured mycobiologically. The progressive leprosy related lesions are the result of chronic nerve damage; ocular lesions due to infiltration by Mycobacterium leprae did not develop. Based on the factors found to be associated with development of the most visually significant findings (posterior synechia, keratitis, and cataract) certain patients should be targeted at discharge for active follow up eye care. We suggest that patients with lagophthalmos (even in gentle closure), trichiasis, small pupils, and posterior synechiae should be screened regularly for the development of lagophthalmos in forced closure, keratitis, and cataract.

Adult↗
PubMed1999

Creation and testing of a practical visual function assessment for use in Africa: correlation with visual acuity, contrast sensitivity, and near vision in Malawian adults.

AIM: To develop and test a practical visual function assessment for use in developing countries. METHODS: Using focus group discussions and interviews with eyecare workers and low vision specialists in Malawi, 13 questions related to visual characteristics of activities of daily living were designed. Patients presenting to an eye clinic were recruited and interviewed. Visual acuity, near vision, and contrast sensitivity were measured. Analysis sought to determine the degree of correlation between the vision indices and visual function. RESULTS: The visual function questionnaire was easy to administer. Visual function correlated with visual acuity, contrast sensitivity, near vision, and patient reported visual problem. People with a higher frequency of "not applicable" responses had lower visual function scores. Multivariate modelling revealed that visual acuity and number of questions felt to be applicable were independently associated with visual function. Reducing the questionnaire to nine questions did not affect the degree of correlation with any of the visual indices. CONCLUSION: The authors' visual function assessment correlates well with different measures of visual acuity. People with reduced vision for a prolonged period may no longer consider doing certain tasks and the number of questions considered appropriate by an individual may be an additional measure of visual function. Assessment of visual function by health workers may be a valuable tool in improving surgical uptake by encouraging both health personnel and patients to recognise that they have difficulties undertaking activities of daily living as well as a measure of monitoring and evaluating cataract outcomes.

Contrast Sensitivity↗
PubMed1999

Corneal endothelial deposits in patients with HIV infection or AIDS: epidemiologic evidence of the contribution of rifabutin.

BACKGROUND: We noted a number of patients with unusual fine, stellate corneal endothelial deposits. The distribution of the deposits appeared to be concentric, involving mostly the periphery. We postulated that the changes might be related to the use of rifabutin rather than to cytomegalovirus (CMV) retinitis. We conducted a study among patients infected with HIV to assess the factors associated with these corneal changes. METHODS: All patients with HIV infection or AIDS who presented to an ocular AIDS clinic in Vancouver between May 16 and July 4, 1996, were examined for the presence of corneal endothelial deposits. The clinical history was noted in a masked fashion. RESULTS: Of the 162 patients examined, 25 showed fine, diffuse, white, stellate corneal endothelial deposits occurring predominantly in the periphery. The presence of the deposits was associated with rifabutin use (odds ratio 5.6, 95% confidence interval 2.5 to 12.9) independent of the presence of CMV retinitis, the CD4 count, the presence of uveitis and use of other medications. INTERPRETATION: Corneal endothelial deposits found in patients with HIV infection are associated with rifabutin use independent of the presence of CMV retinitis. The deposits should be monitored to determine their clinical significance.

Acquired Immunodeficiency Syndrome↗
PubMed1999

Age-related macular degeneration in Chinese-Canadians.

BACKGROUND: Ethnicity has long been suspected to play a role in the risk of macular degeneration as well as its neovascular complications. We carried out a study to determine the prevalence of retinal diseases in Chinese-Canadians presenting for fluorescein angiography compared to a matched group of Canadians of European origin. METHODS: We reviewed 20,000 consecutive fluorescein angiograms obtained between December 1987 and November 1993 at a tertiary referral centre for ophthalmic care in Vancouver. All patients identified by name as being of Chinese ancestry were identified and matched to a patient of European ancestry. The two groups were compared in regard to the prevalence of specific retinal diseases, including age-related macular degeneration (AMD). RESULTS: Among the first 10,000 fluorescein angiograms, 417 patients of Chinese ancestry were identified, of whom 61 (14.6%) had the primary diagnosis of AMD. The rate among the patients of European ancestry was 30.4% (127/417) (odds ratio [OR] 2.12, 95% confidence interval [CI] 1.79 to 2.56) (p < 0.001). A total of 88 ethnic Chinese patients were identified among the subsequent 10,000 angiograms. Pigment epithelial detachments were more than twice as common in the overall group of ethnic Chinese patients as in their counterparts of European ancestry (OR 2.6, 95% CI 0.7 to 10.1). Choroidal neovascularization was 1.6 times more common in the latter group (95% CI 0.98 to 2.8). INTERPRETATION: The findings support the growing clinical observations of a lower prevalence of AMD in nonwhite populations in addition to an increased prevalence of pigment epithelial detachments in ethnic Chinese patients.

Aged↗
PubMed1998

Association between measures of vitamin A and the ocular fundus findings in cerebral malaria.

OBJECTIVE: To investigate the relationship between serum vitamin A levels and conjunctival impression cytology and retinal whitening present in Malawian children with cerebral malaria. METHODS: Standard retinal examination and conjunctival impression cytology were performed at hospital admission on 101 consecutively admitted children with cerebral malaria. Blood samples were drawn from 56 children at 24 hours, frozen at -20 degrees C, and transported for assessment of vitamin A levels by high-performance liquid chromatography. Associations among fundus findings and vitamin A measurements were sought. RESULTS: The whitening of the retina that we have previously described in children with cerebral malaria was found to be associated with a mean+/-SD serum vitamin A level of 0.29+/-0.1 micromol/L, compared with a mean vitamin A level of 0.41+/-0.2 micromol/L in children without retinal whitening. Children with retinal whitening were 2.77 (95% CI, 1.06-7.3) times more likely to have abnormal conjunctival impression cytology results than those without whitening. No child had any clinical or ophthalmologic evidence of chronic vitamin A deficiency. CONCLUSIONS: The retinal whitening described in children with cerebral malaria is associated with low serum vitamin A levels and with abnormal conjunctival impression cytology results and may be due to acute vitamin A deficiency at the tissue level.

Child↗
PubMed1998

Visual function among corneal disease patients waiting for penetrating keratoplasty in British Columbia.

PURPOSE: We sought to test the applicability of a well-documented visual function assessment (VF-14) in corneal disease patients wait-listed for penetrating keratoplasty to determine if it would be a valuable addition to a priority scheme. METHODS: A systematic random sample of patients wait-listed for penetrating keratoplasty in British Columbia was selected and administered the VF-14. RESULTS: The mean VF-14 score was 67.2; it was correlated with best corrected vision. Immigrants had lower VF-14 scores and they considered fewer of the questions applicable to them. There was a correlation between the number of questions considered applicable and the VF-14 score. CONCLUSIONS: As currently constituted the VF-14 is probably not a useful tool in a multi-cultural population in North America. We propose revisions to the visual function assessment and suggest its inclusion in a priority scheme for penetrating keratoplasty that also includes pain and other clinical indices.

British Columbia↗
PubMed1998

Retinal nerve fiber layer height in high-tension glaucoma and healthy eyes.

PURPOSE: To determine the correlations between the retinal nerve fiber layer height measured by Heidelberg Retina Tomograph, version 1.11, and visual field indices in healthy individuals and patients with glaucoma. METHODS: One eye was randomly chosen from 48 patients with glaucoma and 60 healthy individuals. All participants were classified using Humprey visual field, program 30-2 (Humphrey Instruments, Inc., San Leandro, CA, U.S.A.); mean deviation, pattern standard deviation, short-term fluctuation, and corrected pattern standard deviation were measured. Superior and inferior mean deviation were calculated. For each participants the mean Heidelberg Retina Tomograph was generated from three 10 degrees Heidelberg Retina Tomograph pictures. The Student t test was used to compare healthy and glaucomatous retinal nerve fiber layer (RNFL) mean degree values every 5 degrees. A global measurement, superior sector (25 degrees-125 degrees), nasal sector (130 degrees-230 degrees), inferior sector (235 degrees-335 degrees), temporal sector (340 degrees-20 degrees), and polar sector (superior + inferior) were calculated. The global, superior, nasal, inferior, temporal, and polar RNFL height (RNFLH) were compared between healthy individuals and patients with glaucoma. The correlation between global, superior, inferior, and polar retinal nerve fiber layer height and visual field was calculated. RESULTS: A significant difference was found for RNFLH mean from 45 degrees to 330 degrees and for the distribution of the means (as reflected by the standard deviation) from 85 degrees to 100 degrees, 260 degrees to 295 degrees, and 335 degrees to 5 degrees. From these data we created three new sectors: new superior sector (from 85 degrees to 100 degrees), new inferior sector (from 260 degrees to 295 degrees), and new polar sector (combining the new superior and the new inferior sector). Comparing the healthy individuals to the patients with glaucoma, the mean RNFLH values for each sector were found to differ significantly (p < 0.001), with the exception of the temporal sector. Significant correlations (p < 0.001) between the global RNFLH and mean deviation (r = -0.36), pattern standard deviation (r = 0.49), and corrected pattern standard deviation (r = 0.48) were found in healthy participants and those with glaucoma. The strongest correlations (p < 0.001) were found between the pattern standard deviation and the corrected pattern standard deviation with the new polar sector (r = 0.60 and r = 0.59, respectively). CONCLUSIONS: We found that the strongest correlations with the visual field were with the new polar and new inferior sector.

Aged↗
PubMed1998

An epidemiologic investigation of unexpected refractive errors following cataract surgery.

OBJECTIVE: To determine the extent and magnitude of unexpected refractive errors following cataract surgery with intraocular lens (IOL) implantation and to determine what characteristics were associated with the errors. DESIGN: In this nonconcurrent prospective study, preoperative, intraoperative and postoperative information was collected from the charts of the 523 consecutive patients who underwent cataract extraction and polymethylmethacrylate IOL implantation performed by one of nine participating surgeons between Jan. 1 and Apr. 30, 1995, or the same dates in 1996. SETTING: University-affiliated eye care centre in Vancouver. OUTCOME MEASURE: Postoperative excess correction, calculated for each patient by subtracting the actual postoperative spherical equivalent from the expected spherical equivalent. Eyes with an excess correction of more than 1.00 dioptre were considered "overcorrected." RESULTS: Univariate analysis showed that the formula used to calculate the lens power, axial length, year of surgery, A-constant/surgeon factor used and lens manufacturer were associated with overcorrection. In a logistic regression model, lens manufacturer was the only variable independently associated with overcorrection. CONCLUSIONS: Routine reporting and follow-up is necessary to identify this kind of "outbreak" and the associated factors. The current guidelines of the Health Protection Branch, Health Canada, for evaluation of IOLs that have changed manufacturers are not adequate to identify the kind of error that we detected.

Aged↗
PubMed1997

HIV and AIDS and the eye in developing countries: a review.

An estimated 30 million people worldwide have been infected with the human immunodeficiency virus, the causative agent of the acquired immunodeficiency syndrome. Of these, 90% live in developing countries from where there is relatively little published information about the ocular manifestations of human immunodeficiency virus and acquired immunodeficiency syndrome. We review the information available from Africa, Latin America, and Asia. The prevailing ocular manifestations differ in some developing countries compared with those in the industrialized countries. These differences most likely result from different socioeconomic conditions and basic health care availability and from different patterns of endemic disease present before the human immunodeficiency virus epidemic.

Africa↗