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Biomedical subjects

D H Chan

Publications and source records attributed to D H Chan.

12 recordsLinked to original sources
PubMed2001

Clinical features of 46 eyes with calcified hydrogel intraocular lenses.

PURPOSE: To clarify the clinical features of delayed calcification of hydrogel intraocular lenses (IOLs) based on observation of a large case series. SETTING: Ophthalmology department of 2 university teaching hospitals, Hong Kong, China. METHODS: The first 44 patients with a known diagnosis of calcified IOL were recruited. Medical and ophthalmic histories were obtained. Surgical details, surgical complications, and visual acuity before and after IOL implantation were also retrieved. Patients then had a visual acuity test, a slitlamp examination of the features of the IOL calcification, and a fundus examination for clarity of view. RESULTS: Forty-six eyes of 44 patients had IOL calcification. All had a Hydroview IOL. The onset was from 4 to 26 months after surgery. Ninety-three percent of eyes had generalized IOL calcification, and 96% had forceps marks on the IOL. Mean visual acuity deteriorated from 0.4 at 3 months to 0.13 at 19 months. Visual loss was more severe in patients with diabetes mellitus or ischemic heart disease and in those in which the IOL calcified earlier after implantation. CONCLUSION: All cases of IOL calcification were delayed in onset. The presence of forceps marks may provide a clue to the pathogenesis. Bilateral but asymmetric involvement in 2 patients suggests that the IOL was involved in the pathogenesis. Affected patients lost an average of 2.8 Snellen lines of visual acuity. Some eyes progressed more rapidly; however, the modulating factors remain unknown.

Aged↗
PubMed1998

Benign fibrous histiocytoma of the choroid.

Benign fibrous histiocytoma (BFH) is a common soft tissue tumour. However, its occurrence in the orbit was not well recognised in the past. It is only in recent years that this condition has become more frequently diagnosed. Now, it is believed to be the commonest mesenchymal tumour of the orbit in adults. Its occurrence in the uveal tract is, however, exceedingly rare. Only one case of presumed fibrous histiocytoma of the choroid has been reported in the literature. We report herein a case of BFH of the choroid in the left eye of a Chinese woman. The patient presented with a huge but asymptomatic raised choroidal mass. Results of choroidal biopsy showed no sign of malignancy but definitive diagnosis could not be made. Enucleation was finally performed. The diagnosis was made on detailed evaluation of the results of the immunohistochemical staining and the ultrastructural findings. The patient remained well at the latest follow-up, which was 33 months after enucleation. Although BFH of the choroid is vary rare, its benign nature and the availability of choroidal biopsy for tissue diagnosis make it important to include this as one of the differential diagnoses for amelanotic choroidal mass.

Aged↗
PubMed1989

Opportunistic research in general practice using a low cost microcomputer based medical record system as a tool.

A low cost microcomputer-based medical record system was used to facilitate opportunistic research projects in the teaching clinic of the Chinese University of Hong Kong. An example of an actual clinical trial comparing the effectiveness of three methods of teaching breast self-examination to clinic patients was used and the process of setting up the research protocol, the sampling of patients, and the analysis of early results after one and a half years were described. It was found that the sampling bias in opportunistic research was that subjects selected were more likely to be older with more problems, and have a higher attendance rate at the clinic. The bias could be corrected during the analysis of data by stratifying the selected sample into groups of different attendance rates. Another potential sampling bias was due to non-compliance of both the patients and the clinical staff. However, it was found to be possible to obtain useful results from opportunistic research. It was easy to implement this type of research with the help of a computerized medical record system.

Adult↗
PubMed1988

Implementation of a microcomputer-based opportunistic health maintenance programme in a general practice teaching clinic.

The general practice teaching clinic at the Chinese University of Hong Kong uses a microcomputerbased medical record system. To implement a uniform and up-to-date health maintenance programme, a set of protocols has been written for a list of health maintenance items, and the computer has been programmed to identify the items which should be carried out at each patient encounter. Over a period of 16 months, after the start of this programme, 99% of the 1120 clinic patients had a minimum of two items performed. Of a selected sample of 203 patients 119 attended the clinic more than once in the same period and 47% of these patients had all of the health maintenance items recommended for their age and sex group completed. Abnormal screening results led to action by the general practice team. The process of implementing a health maintenance programme has helped the team to discuss current recommendations and to agree on standards. The programme has also helped with undergraduate teaching. The automated opportunistic health maintenance programme is a practical tool for improving patient care.

Adolescent↗
PubMed1987

A microcomputer-based computerized medical record system for a general practice teaching clinic.

A low-cost and user-friendly computerized medical record system that includes patient demographic data, family genogram and social information, problem list, medication list and repeat prescription, progress notes, and laboratory data has been developed for a general practice teaching clinic. The system also has an automated health maintenance and disease management package, a number of research report programs, and a basic accounting package. The computerized medical record system has provided a very valuable tool for improving patient care, teaching, and general practice research. A standard software package has been developed for other small to medium-sized practices to use without having to redevelop their own software.

Computers↗
PubMedDate not supplied

Problem-based small-group learning via the Internet among community family physicians: a randomized controlled trial.

The use of the Internet makes it possible to bring together learners and teachers from rural areas and academic centers and to deliver well-accepted educational materials quickly and effectively. The objective of this study was to determine feasibility and the effectiveness of a problem-based small-group learning (PBSGL) intervention conducted via the Internet in a randomized controlled trial. A group of 23 family physicians from rural Northern Ontario practices and across Canada were randomly assigned to a study group (n = 11) and a control group (n = 12). The study group spent two months discussing the topic of depression in the elderly with the help of a facilitator and two geriatric psychiatrists. The control group was given similar educational resources via the Internet but without the benefit of the small-group interaction. Outcome measures included qualitative feedback from the learners and teachers as well as a Multiple Choice Questions (MCQ) test before and after the study. The study provided important insight into the feasibility, keys to success, utility of Internet-assisted education from an education and evaluation perspective. Although the MCQ testing used revealed no significant differences between the study group and the control group, the usefulness of the measure is considered within the context of the educational approach. It is unclear whether this method of continuing medical education (CME) represents an effective way to conduct such activities.

Adult↗