Posterior vitreous fluorophotometry in normal subjects

Area of Science:

• Ophthalmology
• Biomedical Engineering

Background:

• Vitreous fluorophotometry is a key technique for assessing ocular barrier function.
• Establishing normal reference ranges is crucial for diagnosing ocular pathologies involving leakage.

Purpose of the Study:

• To determine normal vitreous fluorescein concentration and permeability index values in healthy subjects.
• To establish criteria for identifying abnormally high fluorescein leakage in the posterior vitreous.

Main Methods:

• Vitreous fluorophotometry was performed using the Fluorotron Master after intravenous fluorescein injection (14 mg/kg) in 22 normal subjects.
• Fluorescein concentration was measured at 3 mm from the retina and averaged over the posterior 6 mm.
• Permeability index was calculated 60 minutes post-injection.

Main Results:

• Mean post-injection vitreous fluorescein concentrations ranged from 1.7-4.3 ng/mL at 30 minutes and 7.1-10.8 ng/mL at 60 minutes.
• The permeability index ranged from 0.92-1.19 X 10(-7) cm/s.
• Reproducibility of measurements varied from 17% to 49% depending on the analysis method.

Conclusions:

• Normal reference ranges for posterior vitreous fluorescein concentration and permeability were established.
• Abnormally high fluorescein leakage may be indicated by a 60-minute vitreous concentration >14.3 ng/mL or a permeability index >2 X 10(-7) cm/s.