Optical properties of miniaturized endoscopes for ophthalmic use

Abstract

Endoscopes for use in ophthalmology can now be manufactured with overall intraocular diameters smaller than 0.89 mm. Endoscopes based on gradient-index lenses yield a higher resolution than those making use of ordered fiber bundles having the same diameter. Likewise, endoscopes with optical elements having a diameter of 0.50 mm yield a higher resolution than those with smaller diameter (0.35 mm). Thanks to the miniaturization, a working channel can also be integrated within the tube of the endoscope instead of being a part of the illumination bundle. This allows the design of new endoscopic devices including various surgical instruments. Preference is given to an endoscope with an integrated aspiration/irrigation system or with a fiber for laser therapy. The potential phototoxicity of these systems is briefly discussed.