Edinburgh, United Kingdom, April 23, 2011 --(PR.com
)-- In a recently published paper in the Royal Society Interface journal Edinburgh Instruments (EI) together with NHS Princess Alexandra Eye Pavilion and Heriot-Watt University explored the possibility of early cataract diagnostics based on tryptophan fluorescence (TF).
According to the World Health Organisation, cataract is the leading cause of blindness worldwide affecting some 17 million people and causing 1.3 million cataract operations annually in the United States alone.
Currently, methods of cataract detection are based on subjective observation of lens opacity by Rayleigh light scattering. However, they would not provide the protein-level detail offered by TF due to the limitation of these scattering techniques as the sizes of the structural defects must be comparable with the wavelength of light used, i.e. 400–600 nm. Hence, these methods do not reveal structural changes on a molecular level.
TF has been widely used for monitoring protein changes in biophysical research to detect protein folding, conformation and aggregation by virtue of shifts in the emission spectrum in different polar microenvironments.
By creating artificial cataracts in the lenses from pigs’ eyes, by means of UV radiation, experiments show that TF offers a sensitive method for monitoring very early changes in the lens structure that cannot be detected by the standard slit-lamp method. Spectral measurements were taken using an EI FLS920 spectrometer in a temperature controlled 1 cm quartz cuvette in Phosphate Buffer Solution at 22°C, this temperature retained uniform tissue viability over 16 hours.
Exploiting this discovery should allow the development of a clinically useful tool sensitive enough to detect, diagnose and monitor lens change before significant damage, light-scattering, aggregation and visual impairment occurs. This method could help to establish the point at which the irreversible crystalline protein change has occurred triggering the need for surgical intervention. It could also act as a more precise screening method for possible pharmacological treatment.
In addition, clinical applications of this method would help in diagnostics of early stages of metabolic disorders as, e.g. diabetes, preventative treatment of which could delay the development of chronic diseases.