ommatidium
Quick Summary
An ommatidium is a fundamental unit of a compound eye, found in arthropods like insects. Each ommatidium functions as a tiny, independent eye, composed of a lens, a crystalline cone, and light-sensitive retinula cells that form a rhabdom. These cells are surrounded by pigment cells that prevent light from spreading to adjacent ommatidia.
Multiple ommatidia, numbering from a few dozen to tens of thousands, are arranged to form the faceted surface of the compound eye. Each ommatidium captures light from a small portion of the visual field. The brain then processes these individual inputs, creating a mosaic image of the surroundings. This structure allows for a wide field of vision and the detection of movement and color.12
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photoreceptionCompound eyes…is an independent unit (the ommatidium), which views the light from a small region of the outside world. In superposition eyes the optical elements do not act independently; instead, they act together to produce a single erect image lying deep in the eye. In this respect they have more in…
Read More…is an independent unit (the ommatidium), which views the light from a small region of the outside world. In superposition eyes the optical elements do not act independently; instead, they act together to produce a single erect image lying deep in the eye. In this respect they have more in…
Read More- photoreceptionImage formation
Each ommatidium consists of a cornea, which in land insects is curved and acts as a lens. Beneath the cornea is a transparent crystalline cone through which rays converge to an image at the tip of a receptive structure, known as the rhabdom. The rhabdom is…
Read MoreEach ommatidium consists of a cornea, which in land insects is curved and acts as a lens. Beneath the cornea is a transparent crystalline cone through which rays converge to an image at the tip of a receptive structure, known as the rhabdom. The rhabdom is…
Read More - photoreceptionImage formation
…that in apposition eyes each ommatidium is independent and sees a small portion of the field of view. The field of view is defined by the lens, which also serves to increase the amount of light reaching the rhabdom. Each rhabdom scrambles and averages the light it receives, and the…
Read More…that in apposition eyes each ommatidium is independent and sees a small portion of the field of view. The field of view is defined by the lens, which also serves to increase the amount of light reaching the rhabdom. Each rhabdom scrambles and averages the light it receives, and the…
Read More - photoreceptionWavelength and plane of polarization
…the various photoreceptors in each ommatidium do have the capacity to resolve two other features of the image, wavelength and plane of polarization. The different photoreceptors do not all have the same spectral sensitivities (sensitivities to different wavelengths). For example, in the honeybee there are three photopigments in each ommatidium,…
Read More…the various photoreceptors in each ommatidium do have the capacity to resolve two other features of the image, wavelength and plane of polarization. The different photoreceptors do not all have the same spectral sensitivities (sensitivities to different wavelengths). For example, in the honeybee there are three photopigments in each ommatidium,…
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