The blood-retinal barrier in diabetes during puberty

J. R. de Abreu, R. Silva and J. G. Cunha-Vaz
Department of Ophthalmology, Coimbra University Hospital, Portugal.

OBJECTIVE: To assess the alteration of the blood-retinal barrier in patients with type I diabetes during puberty. DESIGN: A 7-year prospective study evaluated retinal changes occurring in diabetic children during puberty. Patients between the ages of 10 and 20 years underwent annual ophthalmologic examinations that included fluorescein angiography and vitreous fluorophotometry. SETTING: Clinical research facility. PATIENTS: Fifty-seven diabetic children met preset eligibility criteria. During the study, 241 ophthalmologic examinations were scheduled and 210 (87.1%) were performed. MAIN OUTCOME MEASURE: Vitreous fluorophotometry penetration ratio (VFPR) was used to indicate blood-retinal barrier permeability. RESULTS: No sign of retinopathy was detected before puberty (age 13 years for boys and 11 or 12 years for girls). The prevalence of retinopathy in the 4 years immediately after puberty was 6%. In the next 4 years, the prevalence was 29.6% (P = .0003). When all VFPRs were correlated with age, and data for male and female patients were analyzed separately, we found that the lowest VFPRs occurred at the expected time of puberty. When patients were paired by gender and duration of diabetes, there was a significant difference between VFPR values before and after puberty (P = .03). Also, a progressive deterioration of the blood-retinal barrier became apparent when only VFPR values after puberty were considered. CONCLUSIONS: These results support the view that the blood-retinal barrier remains stable until puberty, achieving a maximum of efficiency and protection. A progressive decline then begins, suggesting that this period of growth is associated with factors that, under the influence of diabetes, contribute to the progressive damage of the blood-retinal barrier.