Abstract
Purpose :
Insulin resistance (IR) and vitamin D deficiency (VDD) often foreshadow a diagnosis of diabetes, but their serologic determination is neglected because of time and expense. We evaluated the number of sub-clinically visible retinal micro-aneurysm (MA#) using highly sensitive 580 nm multi-spectral retinal imaging (MSI) against IR and VDD.
Methods :
Thirty (n=19 M; n=11 F) non-diabetic optometrists (n=54 eyes, 6 unreadable), 53.5 ± 7.6 yrs, were imaged at a professional conference using MSI (Annidis Corporation, Ottawa, Canada). A 6 parameter blood panel requisition: fasting glucose (FBS), 2 hr glucose (GTT) tolerance, HbA1c, fasting insulin, 2 hr insulin and 25 OH vitamin D liver reserve status were provided to each participant. MSI images were reviewed by a masked observer using an EDTRS 7 standard field overlay, counting central 30 degree MA#. Correlation r determined the relationship between MA# and, serology / calculated IR measures (Microsoft Excel, P<0.05 significant).
Results :
Results: Most common clinical parameter used to diagnose diabetes; BMI, 2hr GTT and HbA1c were uncorrelated with MA#, while less commonly evaluated parameters were significant:
FBS r = 0.32 P =0.02 ; HOMA-1R r = 0.40 P = 0.002
Fasting Insulin r = 0.40 P= 0.003 ; HOMA-2R r = 0.41 P = 0.002
2 hr Insulin r = 0.29 P = 0.08 trend ; QUICK-1 r = - 0.47 P = 0.0004
25 OH vitamin D r = - 0.32 P = 0.02 ; Insulin Sensitivity r = - 0.51 P =0.00008
Beta cell function r = 0.32 P = 0.02 ; Insulin Resistance r = 0.41 P = 0.002
Conclusions :
Subclinical MA, invisible to non-spectral cameras but observed with multi-spectral imaging, correlate with insulin, pancreatic function, vitamin D status and calculated measures of IR. Future diabetes intervention research should focus upon MSI MA# as an actionable pre-diabetes and pre-retinopathy risk factor.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.