The relationship of central foveal thickness to urinary iodine concentration in retinitis pigmentosa with or without cystoid macular edema.

IMPORTANCE: Current treatments for cystoid macular edema (CME) in retinitis pigmentosa (RP) are not always effective, may lead to adverse effects, and may not restore visual acuity. The present research lays the rationale for evaluating whether an iodine supplement could reduce CME in RP. OBJECTIVE: To determine whether central foveal thickness (CFT) in the presence of CME is related to dietary iodine intake inferred from urinary iodine concentration (UIC) in nonsmoking adults with RP. DESIGN, SETTING, AND PARTICIPANTS: We performed a cross-sectional observational study of 212 nonsmoking patients aged 18 to 69 years referred to our institution for RP with visual acuity of no worse than 20/200 in at least 1 eye. EXPOSURE: Retinitis pigmentosa with or without CME. MAIN OUTCOMES AND MEASURES: With the eye as the unit of analysis, the relationship of log CFT measured by optical coherence tomography to UIC measured from multiple spot samples and represented as a 3-level classification variable (<100, 100-199, and ≥200 µg/L), assigning greater weight to patients with more reliable UIC estimates. RESULTS: Analyses were limited to 199 patients after excluding 11 who failed to return urine samples for measuring UIC and 2 outliers for UIC. Of the 199 patients, 36.2% had CME in 1 or both eyes. Although log CFT was inversely related to UIC based on findings from all eyes (P = .02), regression of log CFT on UIC separately for eyes with and without CME showed a strong inverse significant relationship for the former group (P < .001) and no significant relationship for the latter group (P = .66) as tested. For the eyes with CME, CFT ranged from a geometric mean of 267 µm for a median UIC of less than 100 µg/L to a geometric mean of 172 µm for a median UIC of 200 µg/L or greater. In contrast, we found no significant association between CME prevalence and UIC based on the entire sample as tested (odds ratio, 1.01 [95% CI, 0.38-2.67]; P = .99). CONCLUSIONS AND RELEVANCE: A higher UIC in nonsmoking adults with RP was significantly associated with less central foveal swelling in eyes with CME. Additional study is required to determine whether an iodine supplement can limit or reduce the extent of CME in patients with RP.

Urinary albumin excretion rate: a risk factor for retinal hard exudates in macular region in type 2 diabetic patients.

BACKGROUND: The various risk factors for retinal hard exudates are still poorly understood in type 2 diabetic patients. The aim of this study was to determine the association between urinary albumin excretion rate (UAER) and hard exudates in macular region in north Chinese patients. METHODS: A total of 272 patients (272 eyes) were enrolled for this study, including 154 subjects from group 1 (mild hard exudates), 91 subjects from group 2 (moderate hard exudates) and 27 subjects from group 3 (severe hard exudates) confirmed using colour fundus photography, optical coherence tomography (OCT) as well as slit-lamp biomicroscopy with 78 diopter (D) lens. Each participant underwent a comprehensive assessment that included biochemical, clinical characteristics test and detailed ophthalmic evaluation. One-way analysis of variance (ANOVA) test and chi-square test were performed to analyze the fasting blood glucose (FBG), glycated hemoglobin (HbA1c), total cholesterol (TC), low density lipoprotein (LDL), high density lipoprotein (HDL), triglycerides (TG), full blood counts, urinary albumin excretion rate (UAER), blood creatinine (CREA), duration of diabetes, body mass index (BMI), systolic blood pressures (SBP) and diastolic blood pressures (DBP) between groups. Ordinal logistic regression analysis was further performed in order to eliminating the possible confounding factors. RESULTS: Three groups were matched in terms of age and gender. Risk factors which showed significant difference between groups include FBG (P < 0.001), HbA1c (P < 0.001), LDL (P < 0.001), UAER (P < 0.001), duration of diabetes (P = 0.001), TC (P = 0.005), SBP (P = 0.026), CREA (P = 0.004) and haemoglobin (Hb) (P = 0.012). There was no significant difference between groups for the TG, HDL, DBP, platelet, total white blood cells and BMI. Using ordinal Logistic regression analyses, of all the variables, HbA1c, LDL and UAER which were independent risk factor for hard exudates showed a significantly odds ratio of 1.25, 3.07, and 1.39, respectively. There were also significant differences in UAER level between patients with mild, moderate, severe hard exudates groups (P < 0.001). CONCLUSIONS: UAER was an independent risk factor associated with retinal hard exudates in macular region in type 2 diabetic patients. This study highlights the need for close monitoring and fundus examination for hard exudates in patients with elevated UAER to prevent irreversible visual loss.