Measurement of the retinal irradiation exposure during diaphanoscopic illumination

Abstract

For the visualisation of the intraocular space it is essential to illuminate the inside of the eye. One illumination approach is diaphanoscopy, in which the light of an extraocular source is transmitted through the tissue layers of the eyewall. The transmission properties of these tissues and their irradiation load depend on applied diaphanoscope contact pressure. However, excessive illumination can lead to irreversible photochemical and thermal damage to the retina. In diaphanoscopic illumination, the retina is particularly at risk due to its proximity to the light source. Therefore, the photochemical and thermal retinal hazards, resulting from direct transmitted light through the eyewall, are determined for different applied pressures of the diaphanoscope on the eye (15, 65 and 115 kPa). The study is performed on porcine eyes with different pigmentation. So, the difference in intraocular irradiance, photochemical and thermal hazards, as well as the maximal exposure time is also examined for different pigmentations. For less pigmented eyes the irradiance inside the eye, the photochemical and the thermal hazard are higher than for higher pigmented eyes. The values also become significantly higher for increasing applied pressure with the diaphanoscope but do not exceed given limits in the standard DIN EN ISO 15004-2: 2014.

Keywords

• intraocular illumination
• pigmentation
• retina
• exposure time
• thermal hazard
• photochemical hazard