Interference filter for colour and black-and-white fluorescein angiography

Area of Science:

• Ophthalmology
• Medical Imaging
• Optical Engineering

Background:

• Fluorescein angiography is crucial for diagnosing retinal diseases.
• Traditional excitation filters can lead to pseudo-fluorescence in black-and-white imaging.
• Accurate visualization of fundus topography is essential.

Purpose of the Study:

• To introduce a new dichromic interference filter for fluorescein angiography.
• To evaluate its efficacy in both color and black-and-white fundus imaging.
• To reduce pseudo-fluorescence in angiograms.

Main Methods:

• A dichromic interference filter transmitting blue (<490 nm) and red (>640 nm) light was employed.
• The filter served as the excitation filter in fluorescein angiography.
• An additional absorption filter was used with the interference filter for black-and-white photography.

Main Results:

• The dichromic filter effectively transmitted both blue and red light.
• Red light provided fundus topography details in color photography.
• Pseudo-fluorescence was eliminated in black-and-white angiograms using the combined filters.

Conclusions:

• The new dichromic interference filter is effective for fluorescein angiography.
• It improves image quality by reducing pseudo-fluorescence.
• This technology enhances diagnostic capabilities in ophthalmology.