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Biomedical subjects

D F Chang

Publications and source records attributed to D F Chang.

10 recordsLinked to original sources
PubMed2001

Pars plana vitreous tap for phacoemulsification in the crowded eye.

This technique facilitates phacoemulsification and foldable intraocular lens (IOL) implantation in eyes with extremely crowded anterior segments. An automated pars plana vitreous tap is used to expand the anterior segment when extremely shallow anterior chambers do not deepen sufficiently with viscoelastic injection alone. This technique permits successful completion of pupilloplasty, capsulorhexis, phacoemulsification, and foldable IOL implantation in these high-risk eyes.

Aged↗
PubMed2000

SF-36 health survey: tests of data quality, scaling assumptions, and reliability in a community sample of Chinese Americans.

BACKGROUND: Chinese Americans are one of the fastest growing ethnic groups in the United States; however, language and cultural obstacles have challenged health workers and policy makers seeking to understand the health status and needs of this population. OBJECTIVES: This study is the first to use a large-scale probability design to evaluate the 36-item Short-Form Health Survey (SF-36) in a Chinese population (n = 1,501). METHODS: Using the International Quality of Life Assessment Project protocols, we examine summated-rating scaling assumptions, item-internal consistency, item-discriminant validity, and reliability. RESULTS: Similar to previous studies, our tests indicated that the SF-36 generally met minimum psychometric criteria with high reliability and satisfactory scaling success rates for most scales. However, the performance of the vitality and mental health scales was less satisfactory with regard to discriminant validity and scaling success rates. Notably, our results indicate that VT3 and VT4 ("feel worn out" and "tired", respectively) formed a separate "fatigue" cluster more highly correlated with the mental health scale. However, MH4 and MH5 ("downhearted and blue" [reverse coded] and "been a happy person") were more highly correlated with the vitality scale, suggesting that it may be more meaningful to reorganize the vitality and mental health items along the dimensions of well-being and distress. CONCLUSIONS: These results are interpreted within a cultural framework; however, additional work is needed to better understand the relationship between vitality and mental health for Chinese Americans.

Adolescent↗
PubMed1999

Phase II results of an intraocular steroid delivery system for cataract surgery.

OBJECTIVE: To evaluate the safety and efficacy of an intraocular biodegradable polymer dexamethasone drug delivery system (DEX DDS) in treating postoperative inflammation after cataract surgery. STUDY DESIGN: Multicenter, randomized, double-masked, parallel group study comparing two dose levels of the DEX DDS to concurrent placebo and no treatment control subjects. PARTICIPANTS: Ninety patients scheduled to undergo extracapsular cataract extraction with phacoemulsification and intraocular lens implantation participated in the study. INTERVENTION: One or two DEX DDSs, each containing 60 microg of dexamethasone, were placed in the posterior chamber after cataract surgery. Patients receiving the placebo received a DDS composed of the same matrix with no active drug. In vivo rabbit studies have determined that the DEX DDS releases dexamethasone into the anterior chamber (AC) for approximately 7 to 10 days. MAIN OUTCOME MEASURES: The AC cells and the AC flare were assessed over a 60-day postoperative period using slit-lamp examination by masked observers. The number and percent of patients in each treatment group requiring additional postoperative topical anti-inflammatory medication were compared. RESULTS: Ninety patients were randomized into 4 treatment groups (30 to the 2 DEX DDS group, 30 to the 1 DEX DDS group, 15 to the placebo DDS group, and 15 to the no treatment group). The control patients required the addition of topical steroids as rescue medication more frequently and sooner than patients receiving DEX DDS (80% vs. 7% at week 2) (P < 0.001). Patients receiving DEX DDS showed a significant reduction in postoperative inflammation as assessed by the combined AC cell and flare scores when compared to the control group from day 3 (P = 0.002) through week 3. The DEX DDS was well tolerated. No clinically significant difference in any safety evaluations, including intraocular pressure, was seen between the DEX DDS-treated and control groups. CONCLUSION: The DEX DDS was safe and effective in suppressing postoperative inflammation after uncomplicated cataract surgery. Additional topical anti-inflammatory drops were not needed for most patients.

Adult↗
PubMed1999

Two clinical trials of an intraocular steroid delivery system for cataract surgery.

PURPOSE: To determine the safety and efficacy of an intraocular dexamethasone drug delivery system (Surodex) in the treatment of inflammation following cataract surgery. METHODS: Surodex is a biodegradable polymer that releases dexamethasone for 7 to 10 days after placement in the anterior segment. Study 1 was a prospective, randomized, double-masked Phase II clinical trial of 90 cataract surgical patients that compared treatment with Surodex to treatment with a placebo drug delivery system and to no anti-inflammatory drug treatment at all. Study 2 was a separate prospective, randomized, double-masked study of 60 cataract surgical patients that compared treatment with Surodex to topical dexamethasone (eye drop) therapy. RESULTS: In the first study, Surodex was superior to placebo in suppressing postsurgical inflammation throughout the 60-day postoperative period, as judged by masked-evaluator, slit-lamp grading of cell and flare. The differences were statistically significant from postoperative day 3 through postoperative week 3. The majority of Surodex patients did not require topical steroid by 2 weeks after surgery (93%) or by 2 months after surgery (88%). In the second study, Kowa laser flare meter readings were lower in Surodex patients throughout the 90-day postoperative period. The results were statistically significant at 4, 8, and 15 days following surgery. There were no significant adverse complications of Surodex in either study. CONCLUSION: Surodex was safe and effective in suppressing postcataract surgery inflammation and appears to be a promising alternative to topical steroids.

Aged↗
PubMed1997

Aqueous hyaluronic acid concentration: comparison in pediatric and adult patients.

PURPOSE: To determine if there is an age-related increase in human aqueous hyaluronic acid (HA) concentration. METHODS: HA concentrations were measured in 102 specimens of human aqueous humour obtained during intraocular surgery. Patient age ranged from one month to 93 years. Measurement of the HA concentration in the specimens was performed by a modified ELISA-like assay using a biotinylated HA-binding peptide. RESULTS: An approximate five-fold increase in the mean aqueous HA concentration was observed between the pediatric (0.33 microgram/ml, n = 5) and the adult patients (1.72 micrograms/ml, n = 97, p < 0.0002). Among the adult patients, however, there was a poor correlation between age and aqueous HA concentration. CONCLUSIONS: Adult aqueous humor has a significantly higher HA concentration than aqueous obtained from pediatric patients. The source of this increase is unclear, but may be from anterior segment production of HA, or alternatively, from anterior diffusion of vitreous HA.

Adult↗
PubMedDate not supplied

Congenital orbital teratoma: report of a case with visual preservation.

Congenital orbital teratoma is a rare, but benign cause of unilateral exophthalmos in infants, and therefore a worthwhile differential diagnosis to consider. Despite the grotesque and alarming external appearance of the eye, both it and visual function can be effectively preserved in certain instances with early intervention. A review of the literature accompanies the report of one such case of a successfully salvaged eye following removal of the teratoma. Clinical recommendations are included.

Child, Preschool↗