Digital imaging of the fundus with long-wave illumination

To increase the quality, diagnostic value and use of non-invasive fundus examination with transscleral or transpalpebral long-wave (red and near infrared) illumination.

For fundus visualization we used red light diode sources at 660 nm and near infrared light diode sources at 810, 940 nm. Light radiation from diode sources penetrates into the globe through eyelid skin and sclera. Fundus examination was performed without dye injection and local anesthesia. The technique was called "long-wave fundusgraphy" (LFG).

Comparing with fluorescein angiography additional topographical information was received concerning CNV associated with hemorrhage or subretinal fluid, which masked the true borders of the neovascular component. If CNV is completely invisible under a layer of blood or pigment, on fluorescein angiography only a hypofluorescent area is registered. In such cases fluorescein angiography is insufficient for correct diagnosis. Examination of such patients with 940 nm excluded maximum masking property of blood or pigment deposits and permitted visualization of CNV.

Non-invasive, consecutive long-wave imaging may be useful for CNV detecting and may obtain additional information about fundus structures in patients with dye intolerance, retinal hyperpigmentation, haemorrhage or fluid masking subretinal structures, miosis or in the presence of opaque media.