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Biomedical subjects

P Courtright

Publications and source records attributed to P Courtright.

At least 19 recordsLinked to original sources
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↗
PubMed1997

Excess mortality associated with blindness in leprosy patients in Korea.

Vision loss and blindness are potential complications of leprosy. There is little data available to indicate the impact of eye complications on life expectancy and quality of life. We sought to determine the relative risk of death in blind leprosy patients compared to nonblind leprosy patients. A population-based ocular survey of 510 mycobacteriologically negative leprosy patients in rural South Korea, conducted in 1988, formed the study population. After a 7-year period patients were traced to determine their status (alive, dead, lost to follow up). Blind patients showed a 4.8-fold risk of death, even after adjusting for other factors, compared to nonblind patients. Young blind leprosy patients had the highest relative risk of death. Excess mortality was not associated with any specific cause of blindness, ocular pathology, or type of disease. Findings from our study suggest that all leprosy patients with ocular disabilities (including those released from antileprosy treatment) should be targeted to receive eye care to prevent vision loss. Particular emphasis should be placed on young patients.

Aged↗
PubMed1997

Correlation between the visual field indices and Heidelberg retina tomograph parameters.

PURPOSE: We wished to determine whether a relationship exists between Heidelberg retina tomograph (HRT) parameters and the visual field indices. METHODS: One eye was randomly chosen from 59 normal patients [normal visual field and normal optic nerve head (ONH) and intraocular pressure (IOP) < 21 mm Hg], 64 ocular hypertensive patients (normal visual field and normal OHN and IOP > 22 mm Hg), 124 high-tension glaucoma patients (abnormal visual field and/or abnormal optic nerve and IOP > 22 mm Hg) and 47 low-tension glaucoma patients (abnormal visual field and or optic disc and IOP < 21 mm Hg). All the patients were examined with Humphrey Perimeter, program 30-2, and HRT. Findings were assessed by analysis of variance, Pearson's correlation coefficient, and multiple linear regression. RESULTS: Among all subjects, we noted a statistically significant correlation (Pearson's r, p < 0.001) between cup area, cup/disc area ratio, rim area, rim volume, cup shape measure, and retinal nerve fiber layer cross-section area with mean deviation and corrected pattern SD. Multiple linear regression analysis demonstrated that rim area was the most important predictor of mean deviation and corrected pattern SD. CONCLUSIONS: The presence of significant correlations between some HRT parameters, such as rim area and cup shape measure and visual field indices, suggests that these HRT parameters could be good indicators of the degree of glaucomatous ONH damage.

Glaucoma, Open-Angle↗
PubMed1996

Changing patterns of corneal disease and associated vision loss at a rural African hospital following a training programme for traditional healers.

AIMS/BACKGROUND: Use of African traditional eye medicines (TEM) is associated with the presence of corneal disease, delay in presentation, and vision loss. An interactive training programme was conducted with traditional healers in Chikwawa District, Malawi and changes in the pattern of corneal disease assessed in patients presenting to the district hospital after the training. METHODS: All patients presenting to the district hospital with corneal disease for a 15 month period before intervention and a 12 month period after intervention were enrolled in the study. Interviews and examinations were carried out by the same person using a standardised, pretested form. RESULTS: Among the 175 pre-intervention and 97 post-intervention patients, delay in presentation improved only slightly. Blindness among patients reporting the use of TEM decreased from 44% to 21%; bilateral corneal disease in patients using TEM decreased from 31% to 10%. Multivariate analysis demonstrates that poor vision in corneal disease patients continues to be associated with TEM use and distance from the district hospital. CONCLUSION: As there were no other relevant eye health programmes in the district it is believed that this collaborative eye care programme with the traditional healers was likely to have been responsible for many of the changes in the pattern of corneal disease in the district. Although the changing patterns are encouraging and are likely to improve with additional collaboration, distance to a district hospital will continue to be a barrier to timely use of Western eye care services.

Blindness↗
PubMed1995

Eye care knowledge and practices among Malawian traditional healers and the development of collaborative blindness prevention programmes.

Many African traditional healers provide treatment for eye diseases, yet there is little published information about eye care knowledge and practices among these healers; the information is necessary for the development of collaborative eye care activities with healers. Focus group discussions, in-depth interviews, and a representative sample survey of 107 randomly selected traditional healers in Chikwawa District, Malawi were conducted regarding eye care knowledge and practices. In the survey 68% of healers treated at least one of six common eye conditions. The most common eye condition treated by healers was cataract, followed by conjunctivitis/inflammatory trachoma. The size of the healer's practice, literacy, and great distance to a health facility were positively associated with the provision of eye care. Traditional healers have considerably more eye care interactions with the rural population than existing biomedical health personnel in Chikwawa District. Interviews revealed that most healers were aware of the availability of treatment for common eye conditions at biomedical health facilities and were interested in collaborating with existing biomedical eye care providers. We subsequently developed a collaborative eye care programme with healers in the district and report on early findings. Collaboration with healers in eye care programmes is advocated and recommendations are provided.

Adult↗
PubMed1995

Corneal decompensation after cataract surgery. An outbreak investigation in Asia.

PURPOSE: During 5 days in January 1994, two visiting expatriate ophthalmologists performed extracapsular cataract surgery on 111 patients at a nonprofit hospital in Asia. The authors investigated the development of postoperative corneal edema. METHODS: An epidemiologic and clinical investigation was undertaken by a review of clinical charts, interview of personnel involved, an examination and interview of patients who underwent surgery, and a laboratory simulation of the disinfection procedure used. RESULTS: Follow-up was available on 58% of the patients. The attack rate was at least 37% and likely to be approximately 64%. The attack rate was highest the first 2 days of surgery. Multivariate analysis showed that the day of surgery was the only characteristic significantly associated with the presence of corneal edema. A simulation of the disinfection technique used (soaked in 2% glutaraldehyde and rinsing) showed that significant levels of glutaraldehyde remain in instruments with small lumens after the rinse. CONCLUSION: The epidemiologic data and simulation information are compatible; the lack of adequate rinsing of small lumen instruments soaked in glutaraldehyde is the most probable cause of this incident. Recommendations for surgeons on surgical expeditions are proposed.

Asia↗
PubMed1995

The distribution of kwashiorkor in the southern region of Malawi.

Using existing nutritional survey data collected over an 11-month period during the recent drought, we sought to determine the distribution of kwashiorkor in the ten districts of the Southern Region of Malawi. Sampling and survey methods were identical and considerable efforts were made to ensure comparability. In 23 surveys, 25,824 children were weighed and measured and oedema was recorded. The district-adjusted prevalence of kwashiorkor was 18/1000. The northernmost districts of the Southern Region had rates five to ten times higher than the southernmost districts. Prevalence peaked at 18-23 months and was similar in boys and girls. Dysentery was associated with the presence of kwashiorkor while diarrhoea was not. The distinctive pattern of kwashiorkor in the region suggests that there are characteristics specific to the northern districts that place children in these areas at greater risk of kwashiorkor.

Child, Preschool↗
PubMed1995

Peripheral corneal ulcers associated with use of African traditional eye medicines.

The most common cause of monocular blindness in Africa is corneal opacification. Traditional eye medicines (TEM) are widely used in Africa and their use has been associated with corneal ulceration, however, no controlled studies of the effects of TEM on the cornea have been published. We conducted a case-control study of 39 patients with corneal ulcers matched to controls with severe conjunctivitis. Microbiological investigations were conducted on 20 cases. There was a significant association between corneal ulceration and TEM use and, in particular, peripheral corneal ulcerations were significantly associated with TEM use.

Adolescent↗
PubMed1995

Vitamin A capsule supplementation in Malawi villages: missed opportunities and possible interventions.

A population-based survey was used to assess childhood and maternal vitamin A capsule coverage in Malawi and to investigate missed opportunities for capsule distribution. Overall, 9.3% of children had received vitamin A supplementation in the previous 6 months. Missed opportunities for receiving vitamin A were high in younger children. Fifty-five percent of mothers were covered in 8 villages served by volunteers and 23% in the 58 villages without volunteers. Existing strategies need to be redesigned and new strategies defined. For instance, mothers could receive supplementation during infant BCG vaccination, and children could receive initial supplementation during measles vaccination. Village health volunteers could be used to target children over 2 years of age.

Child Nutritional Physiological Phenomena↗