title: Association between local neuroretinal function and control of adolescent type 1 diabetes.
abstract: OBJECTIVE
  To evaluate associations between neuroretinal function measured with multifocal electroretinogram (mfERG) and disease variables in adolescents with type 1 diabetes and no retinopathy.
  
  
  METHODS
  Fundus photographs, blood glucose (BG) concentration, HbA1c, and monocular mfERG were performed on 115 adolescent patients (mean age ± SD; 15.7 ± 1.8 years) and 30 controls (18.0 ± 2.8 years). All subjects had best-corrected visual acuity ≥ 20/20. The 45° mfERG stimulus included 103 hexagons, reversing between dark and bright according to a pseudorandom m-sequence. Amplitudes (AMPs) and implicit times (ITs) were derived from local mfERG response waveforms, and Z-scores were calculated. Retinal maps of abnormality frequencies were generated. Differences between controls and patients were evaluated using t-tests. Associations between mfERG and age, duration, and diabetes control were examined using linear regression analysis.
  
  
  RESULTS
  Mean mfERG IT was significantly longer in the patients compared with that in the controls (P = 0.019), but AMP was not different (P > 0.05). In all, 26 eyes (23%) of the patients had abnormal IT and 3 eyes (3%) had abnormal AMP. IT abnormalities were essentially distributed randomly across the retina. There were too few AMP abnormalities to examine their retinal distribution. IT was positively correlated with HbA1c (P < 0.0002) but not correlated with diabetes duration, BG, or age.
  
  
  CONCLUSIONS
  Higher long-term blood glucose concentration is associated with degraded neuroretinal function in adolescents with type 1 diabetes and no retinopathy. Over 20% of these patients have abnormal neuroretinal function. It will be important to determine longitudinally whether the relationship between mfERG IT and diabetes control exists within individual adolescent patients.
authors.affiliation: School of Optometry, University of California-Berkeley, Berkeley, California 94720-2020, USA.
authors.forename: Michal
authors.initials: M
authors.lastname: Laron
authors.forename: Marcus A
authors.initials: MA
authors.lastname: Bearse
authors.forename: Kevin
authors.initials: K
authors.lastname: Bronson-Castain
authors.forename: Soffia
authors.initials: S
authors.lastname: Jonasdottir
authors.forename: Barbara
authors.initials: B
authors.lastname: King-Hooper
authors.forename: Shirin
authors.initials: S
authors.lastname: Barez
authors.forename: Marilyn E
authors.initials: ME
authors.lastname: Schneck
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Adams
mesh_terms: D000293:Adolescent; D001786:Blood Glucose / Q000378:metabolism; D003623:Dark Adaptation; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000503:physiopathology*; D004596:Electroretinography; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D008297:Male; D010775:Photic Stimulation; D012160:Retina / Q000503:physiopathology*; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human