Diabetes, hyperglycemia, and central corneal thickness: the Singapore Malay Eye Study.

PURPOSE: To examine the relationship of diabetes and hyperglycemia with central corneal thickness (CCT) in Malay adults in Singapore. DESIGN: Population-based cross-sectional study. PARTICIPANTS: Three thousand two hundred eighty Malay adults ages 40-80 years living in Singapore. METHODS: The study population was selected using an age-stratified random sampling procedure of Malay 40- to 80-year-olds living in the southwestern part of Singapore. Participants had a standardized interview, examination, and ocular imaging at a centralized study clinic. Central corneal thickness was measured with an ultrasound pachymeter, and nonfasting serum glucose and glycosylated hemoglobin (Hb A(1C)) was obtained from all participants. Diabetes was defined as having nonfasting glucose levels of > or =200 mg/dl (11.1 mmol/l), a self-report of diabetic medication use, or physician diagnosis of diabetes. MAIN OUTCOME MEASURES: Central corneal thickness. RESULTS: Of the 3280 (78.7% response) participants, data on CCT were available on 3239 right eyes. Central corneal thickness was normally distributed, with a mean of 541.2 microm. There were 748 persons with diabetes (23.0%). After controlling for age and gender, central corneas were significantly thicker in persons with diabetes than in those without diabetes (547.2 microm vs. 539.3 microm, P<0.001) and, in the total population, with higher serum glucose (539.6, 540.2, 541.3, and 544.4, comparing increasing glucose quartiles; P = 0.023) and higher Hb A(1C) (537.8, 541.0, 541.4, and 545.5, comparing increasing Hb A(1C) quartiles; P<0.001) levels. In multiple linear regression models adjusting for age, intraocular pressure (IOP), body mass index, and axial length, persons with diabetes had, on average, central corneas 6.50 microm thicker than those of persons without diabetes. CONCLUSIONS: This population-based study among Malays showed that diabetes and hyperglycemia are associated with thicker central corneas, independent of age and IOP levels. These findings may have implications for understanding the relationship between diabetes and glaucoma.

A comparison of applanation tonometry using conventional reusable goldmann prisms and disposable prisms.

PURPOSE: To determine the agreement between intraocular pressure (IOP) measurements using conventional Goldmann applanation tonometry (GAT) and Tonosafe disposable prisms, and also to provide a comprehensive cost analysis of the use of both types of prisms METHODS: : In this prospective observational study, 198 eyes of 100 glaucoma patients had their IOPs measured by 5 consultant ophthalmologists. Data were analyzed using the Bland-Altman method of differences, and correlation was measured using the Pearson coefficient. An analysis of the cost incurred using the 2 methods over a 6-month period was performed. RESULTS: The majority were Chinese (82%), with a male preponderance (57%). The range of IOPs as measured by GAT was 4 to 34 mm Hg. Using the Bland-Altman method to compare GAT and disposable prisms, the bias was 0.2 mm Hg. Tonosafe overestimated the IOP by 0.2 mm Hg in the right eye and underestimated it by 0.2 mm Hg in the left eye. The Tonosafe IOP correlated well with GAT, with a Pearson coefficient of correlation(r) of 0.91 (P<0.0005) for the right eye and 0.92 (P<0.0005) for the left eye, respectively. For those with GAT IOP≥21 mm Hg (n=26), Tonosafe underestimated the IOP by 0.35 mm Hg. The cost incurred by Tonosafe prisms was approximately 8 times that of GAT, but the cost differential reverses when GAT had to be replaced after every 100 cycles of disinfection. CONCLUSIONS: We found a good correlation between Tonosafe prisms and conventional GAT in measuring the IOP. Tonosafe prisms may be of use, especially if the risk of transmission of infection is high. However, cost may limit its more widespread use.

Patient acceptance and attitude toward an alternative method of subconjunctival injection for the medical treatment of glaucoma.

PURPOSE: Nonadherence to glaucoma medications may be a major cause of treatment failure. We examined the acceptance of glaucoma patients toward a possible new route of administering glaucoma medication by subconjunctival injection. PATIENTS AND METHODS: Patients were recruited from specialist glaucoma clinics on a voluntary basis. Trained interviewers administered a 30-item questionnaire and an information sheet with details of an alternative subconjunctival injection route involving injections at 3-month intervals. Outcome measures regarding acceptance of the new procedure, social situational factors, disease factors, and treatment factors were assessed. RESULTS: A total of 151 patients participated in this study. Of the 151 patients 112 (74.2%) were willing to have their glaucoma medication given by the new method of subconjunctival injection, 101 of 112 (90.2%) were willing to accept it at the same cost as their present medication, and 87 of 101 (86.1%) were willing to accept it even at a higher cost. These patients tended to be on a greater number of medications (P=0.006), and medicating more frequently in a day (P=0.003). Nine of 10 (90%) patients who were admitted to nonadherence were willing to accept subconjunctival injections at 3-month intervals in place of their topical medication. CONCLUSIONS: Our study found that 74% of glaucoma patients were willing to accept an alternative form of glaucoma treatment through 3-monthly subconjunctival injections. A large proportion of patients who were admitted to nonadherence to topical medication were willing to consider this alternative method of medication. Our findings are helpful when developing patient-acceptable drug-delivery regimes, which may alleviate the need for daily medication.

Central corneal thickness and its associations with ocular and systemic factors: the Singapore Malay Eye Study.

PURPOSE: To examine the association between central corneal thickness (CCT) and potential systemic and ocular factors affecting CCT in an Asian population. DESIGN: Population-based cross-sectional study. METHODS: A total of 3,280 (78.7% response) adults aged 40 to 80 years of Malay ethnicity living in Singapore underwent a standardized interview and ocular and systemic examination at a centralized study clinic. CCT was measured with an ultrasound pachymeter. Blood samples were obtained to determine serum glucose, cholesterol, and triglyceride levels, and urine samples to determine glomerular filtration rate. The presence of diabetes, hypertension, chronic kidney disease (CKD), and metabolic syndrome were defined based on a combination of investigation results and participant's history. RESULTS: CCT was obtained from 3,239 individuals. CCT was normally distributed with a mean of 541.2 microm in the right eye. While controlling for age and gender, CCT was greater in individuals with higher body mass index (BMI) (P = .038), greater intraocular pressure (IOP) (P < .001), greater axial length (P = .005), and greater radius of corneal curvature (P < .001). Individuals with CKD (P = 0.012) and metabolic syndrome (P < .001) also had greater CCT. CONCLUSION: CCT is associated with higher IOP, longer axial length, and greater radius of corneal curvature, as well as higher BMI, metabolic syndrome, and CKD.