Ophthalmic fluorophotometry: a new solid state fluorophotometer

A new low-voltage ophthalmic fluorophotometer is described. A solid state photodetector has been combined with a high-gain, low-noise amplification and synchronous detection system to develop a stable, relatively inexpensive instrument. Reliable measurements of sodium fluorescein concentration in the eye can be made down to 100 ng/ml (0.26 mumol/l) which allows the estimation of corneal permeability and tear flow rates. Preliminary measurements of tear turnover rate using the fluorophotometer are presented.