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Biomedical subjects

C S H Tan

Publications and source records attributed to C S H Tan.

10 recordsLinked to original sources
PubMed2006

Patients' expectation and experience of visual sensations during phacoemulsification under topical anaesthesia.

PURPOSE: To describe what patients expect to see and the visual sensations they actually experience during phacoemulsification under topical anaesthesia. We also sought to determine if patients find their intraoperative visual experience frightening and the factors associated with this. MATERIALS AND METHODS: Ninety-eight patients who underwent phacoemulsification and intraocular lens implantation under topical anaesthesia were interviewed preoperatively on what they expected to see with their operated eye during surgery and again postoperatively on what they actually saw. No patient received counselling about possible intraoperative visual sensations. A logistic (multivariate) regression model was used for statistical analysis. RESULTS: Preoperatively, 36 patients (36.7%) expected at least light perception, 38 (38.8%) expected no light perception, and 24 (24.5%) were unsure what to expect. Some patients also expected a variety of different visual sensations. Postoperatively, all patients (100%) reported seeing light intraoperatively and many experienced various other visual sensations. Nineteen patients (19.4%) found their visual experience frightening. The following factors were statistically associated with a frightening visual experience: preoperative anxiety, previous cataract surgery in the fellow eye, experiencing an intraoperative increase in clarity, not seeing movement intraoperatively, and not knowing what to expect. CONCLUSIONS: The majority of patients in this study either expected that they would see nothing at all during the surgery or were unsure of what to expect. All patients subsequently saw at least some light, and many perceived various other visual sensations that were frightening to nearly one in five patients. Preoperative counselling should inform about possible intraoperative visual experience.

Adult↗
PubMed2006

A survey on the knowledge and attitudes of anaesthesia providers in the United States of America, United Kingdom and Singapore on visual experiences during cataract surgery.

BACKGROUND AND OBJECTIVE: To assess the knowledge, beliefs and attitudes of anaesthesia providers on the patients' possible intraoperative visual experiences during cataract surgery under local anaesthesia. METHODS: Anaesthesia providers from the Ophthalmic Anaesthesia Society (USA); British Ophthalmic Anaesthesia Society (UK); Alexandra Hospital, National University Hospital, Tan Tock Seng Hospital, Singapore General Hospital and Changi General Hospital (Singapore) were surveyed using a structured questionnaire. RESULTS: A total of 146 anaesthesiologists (81.6%), 10 ophthalmologists (5.6%) and 23 nurse anaesthetists (12.8%) responded to the survey. Most respondents believed that patients would experience light perception and many also felt that patients might encounter other visual sensations such as movements, flashes, colours, surgical instruments, hands/fingers and the surgeon during the surgery. A significantly higher proportion of anaesthesia providers with previous experience of monitoring patients under topical anaesthesia believed that patients might experience the various visual sensations compared to those who have not previously monitored. For both topical and regional anaesthesia, anaesthesia providers who routinely counsel their patients are (1) more likely to believe that preoperative counselling helps or (2) were previously told by patients that they could see intraoperatively and/or that they were frightened by their visual sensations. These findings were statistically significant. CONCLUSIONS: The majority of anaesthesia providers in the USA, UK and Singapore are aware that patients may experience a variety of visual sensations during cataract surgery under regional or topical anaesthesia. Those who have previously managed patients undergoing cataract surgery under topical anaesthesia are more likely to believe this compared to those who have not.

Administration, Topical↗
PubMed2005

Epidemiology of pterygium on a tropical island in the Riau Archipelago.

OBJECTIVES: To describe the epidemiology of pterygium among residents of an island in Indonesia and to examine the roles of age and gender as determinants of bilaterality and severity of the disease. METHODS: Voluntary eye screening on Pulau Jaloh, Riau Archipelago, Indonesia. Gender difference was tested using the chi2 test. The difference in age between subjects with and without disease was tested using unpaired Student's t-test. Odds ratio (relative risk) for gender was calculated using logistic regression model with adjustment for age. RESULTS: Of the 550 inhabitants, 477 (86.7%) responded to the eye screening. The overall prevalence rate of pterygium was 17.0%. Out of 211, 48 male (22.7%) and 33 out of 266 female subjects (12.4%) had the disorder, with the gender difference being statistically significant. Adjusted for age, the risk of disease was 3.1-fold higher among the males. In all, 71.6% of subjects with pterygium had bilateral disease. Subjects with pterygium were significantly older, their mean age being 42.9 years compared to 18.7 years among those without disease. The prevalence rates in male subjects increased from age 20 to reach a plateau of 63.6% at age 35 and remained stable thereafter. In the female subjects, the rates also increased with age, albeit at a slower rate, from age 20 to reach a plateau of 46.7% at age 55 and remained stable thereafter. CONCLUSIONS: There is a high prevalence rate of pterygium among the study subjects, with the rates increasing rapidly with age.

Adolescent↗
PubMed2005

An unusual presentation of a giant frontal sinus mucocele manifesting with a subcutaneous forehead mass.

INTRODUCTION: To describe the unusual manifestation of a giant frontal sinus mucocele. CLINICAL PICTURE: A 33-year-old female presented with blurring of vision in the left eye, periorbital swelling and a painless forehead mass. There was proptosis, partial ptosis, and an elongated, soft, subcutaneous mass over the left side of the forehead. CT scan showed a mass arising from the frontal sinus with both intraorbital and intracranial extension. TREATMENT: Surgical excision of the mass confirmed the diagnosis of a mucocele. OUTCOME: Postoperatively, the patient was asymptomatic. CONCLUSIONS: A subcutaneous soft-tissue mass may be the presenting complaint of a frontal mucocele. Careful examination of the surrounding skin may suggest the diagnosis of sinus-related disease and thus direct appropriate investigations.

Adult↗
PubMed2004

Charles Bonnet syndrome in Asian patients in a tertiary ophthalmic centre.

AIMS: To describe the epidemiology of Charles Bonnet syndrome (CBS) among patients in an Asian tertiary ophthalmic centre and to describe the characteristics of the hallucinations experienced. METHODS: 1077 consecutive patients aged 50 years and above were asked a standardised question to determine if they had ever experienced formed visual hallucinations. All patients who experienced these symptoms were further interviewed using a detailed, standardised questionnaire to ascertain if they met the diagnostic criteria established for CBS. RESULTS: There were 491 men (45.6%) and 586 women (54.4%). The best corrected visual acuity ranged from 20/20 to light perception in the better seeing eye and from 20/20 to no light perception in the worse seeing eye. Four patients (0.4%) were diagnosed with CBS; two men and two women. There were two Chinese and two Indians. The average age of the CBS patients was 76.3 years (range 65-90 years). Two patients had cataracts, one had glaucoma, and one had both cataracts and glaucoma. A wide variety of visual hallucinations were reported. Three out of four patients experienced a negative reaction to their hallucinations. Only one patient had discussed his symptoms with a doctor. CONCLUSIONS: This is the first report on the epidemiology of CBS in Asian patients. The prevalence rate of CBS (0.4%) is slightly lower than in comparable studies in non-Asian populations. The nature of the hallucinations experienced were similar to those previously reported.

Aged↗