Trachea in the visual system can be observed by multiple methods.

<p>(A) The tracheal pattern was observed by transmitted light in the whole-mount dissected <i>w</i>¹¹¹⁸ adult eye. The dark pattern is due to loss of transmitted light by light reflection of air-filled tubes. The thicker branches near the base of the retina (Re) are connected to thinner branches that extend into the retina. (B) The tracheal pattern was observed by 633 nm reflected light by confocal microscopy in the whole-mount dissected <i>w</i>¹¹¹⁸ adult eye. (C) The tracheae were visualized by the tracheal markers <i>btl</i>><i>GFP</i> (green) and <i>trh-lacZ</i> (stained with anti-β-Gal, red). The white arrow points to a nucleus expressing <i>trh-lacZ</i>. (D-D”) Visualizing trachea by <i>btl > DsRed</i> (red) in <i>GMR-wIR</i> and by UV-excited autofluorescence (green). One longitudinal optical section of the adult visual system is shown. The arrow points to a branching tracheal tube in the retina. Re: retina; OL: optic lobe; La: lamina; FM: fenestrated membrane (arrowhead). All images in this and the following figures are based on whole-mount fixed tissues. The sections are confocal optical sections.