Acute effects of insulin on aqueous humor flow in patients with type 1 diabetes

James T. Lane, Carol B. Toris, Samer N. Nakhle, David M. Chacko, Yun Liang Wang, Michael E. Yablonski

Research output: Contribution to journalArticle

14 Scopus citations

Abstract

PURPOSE: Previous studies reported reduced aqueous humor flow through the anterior segment of the eye in patients with type 1 diabetes. This study investigates whether reduced flow is the result of the diabetic state or of alterations in glucose or insulin concentrations. METHODS: A cross-sectional study, involving patients with type 1 diabetes and healthy controls, measured aqueous flow at different insulin concentrations. Eleven patients with type 1 diabetes (hemoglobin A1C = 7.0 ± 0.3% [mean ± SEM], normal < 6.5) with no microvascular complications and 17 controls were prospectively studied. Controls were studied fasting and during a hyperinsulinemic-euglycemic clamp (insulin 2 mU/kg per minute). Patients with type 1 diabetes were similarly studied during two euglycemic clamp procedures (insulin 0.5 and 2.0 mU/kg per minute). Aqueous flow was measured by fluorophotometry. Pulsatile ocular blood flow and intraocular pressure were measured with a Langham flow probe. RESULTS: Control subjects had no change in aqueous flow during fasting and hyperinsulinemic conditions (3.0 ± 0.1 vs 2.8 ± 0.1 μl per minute). In the patients with type 1 diabetes, aqueous flow was not decreased with hyperinsulinemia, compared with the low insulin state (P = .7). Compared with control subjects, patients with type 1 diabetes had lower aqueous flow during hyperinsulinemia (2.4 ± 0.1 μl per minute, P = .03) and at lower insulin conditions (2.6 ± 0.1 μl per minute, P < .05). No differences in intraocular pressure or pulsatile ocular blood flow were noted between groups or between insulin states within groups. CONCLUSIONS: Aqueous flow is decreased in patients with type 1 diabetes under euglycemic conditions of high and relatively low insulin concentrations, despite the absence of microvascular complications.

Original languageEnglish (US)
Pages (from-to)321-327
Number of pages7
JournalAmerican journal of ophthalmology
Volume132
Issue number3
DOIs
StatePublished - 2001

ASJC Scopus subject areas

  • Ophthalmology

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