Abstract
Purpose:
The increased rate of the accumulation of advanced glycation end products (AGEs) in the human lens of diabetics versus healthy subjects was first described over 30 years ago and has since been verified by several authors. AGEs exhibit fluorescence unique to their surroundings which can be elicited following excitation. This physiology has now been harnessed in order to recognise and identify Non-Insulin Dependent Diabetes Mellitus (NIDDM) in the population earlier than ever before. NIDDM onset is thought to occur between 4-7 years prior to actual diagnosis today. The predictive value of a high autofluorescence measurement for a diagnosis of diabetes depends on the distribution of lens autofluorescence in a population without known clinical disease. Our aim is to describe the correlation between age and lens autofluorescence using readings obtained by the Clear Path DS-120 biomicroscope and illustrate any relationship between age and lens scatter.
Methods:
Lens autofluorescence testing was carried out on the Clear-Path DS 120 (v. 2.3.0.15) across 14 centres in the US over 13 months from August 2013 to September 2014. Subjects’ age and gender were also recorded. The scanning system is automated, takes 6 seconds to perform from the point of fixation, and incorporates an eye tracker. Data was de-identified, remotely pooled and analysed to establish any relationships between age, fluorescence values and scatter.
Results:
A total of 5,836 patients scans were obtained of which 47.4% were male and 52.6% were female. Subjects ranged from 8-86 years of age with a mean of 44.5 years. A strong direct linear correlation was found between fluorescence values and age between 10-80 years. With the fluorescence value displayed as a ratio against scatter readings we are able identify those above the 85th and 95th percentile of the norm for a given age. With data normalised for age and presented as a Z-score we were again able to highlight those distinctly above normal values. Lens scattering appears to accelerate with age possiblly due to lens damage and cataract formation.
Conclusions:
Our data set confirms a strong direct relationship between AGE autofluorescence and age when using the Clear-Path DS 120. A expected increase in scatter with age is also demonstrated. Further study is required to determine the affect of scatter on the Clear-Path DS 120 scanning system as well as other physiological characteristics.