The hyaloid membrane is a thin structure located in the eye. The spelling of this term is based on the IPA phonetic transcription, which is used to represent the sounds of words. In IPA, the word "hyaloid" is spelled /haɪəlɔɪd/, which indicates the pronunciation of the word. The "h" is silent, and the "y" is pronounced as a long "i". "Membrane" is spelled /ˈmɛm.brən/, with the stress on the second syllable. The combination of these two words forms the term "hyaloid membrane," which refers to a delicate membrane that surrounds the vitreous humor in the eye.
The hyaloid membrane, also known as the hyaloid vitreous membrane or the hyaloid vascular system, is a transparent, delicate film-like structure found in the eye of vertebrates. This specialized connective tissue arises from the embryonic optic vesicle and envelops the developing vitreous humor – a clear, gel-like substance filling the space between the lens and the retina.
The primary function of the hyaloid membrane is to provide structural support and nourishment to the developing eye during embryonic and fetal stages. It acts as a scaffold for the developing vitreous humor and helps maintain its shape and clarity. Additionally, the hyaloid membrane is responsible for facilitating the circulation of nutrients and oxygen within the developing eye.
As the eye matures, the hyaloid membrane undergoes a process known as regression. From the embryonic stage to early childhood, the hyaloid membrane gradually degenerates and eventually disappears, leaving remnants behind. These remnants, called Bergmeister's papilla or Mittendorf's dot, may occasionally be visible on the anterior surface of the lens in adults.
Any anomalies or abnormalities in the regression of the hyaloid membrane can lead to various eye conditions, such as persistent hyperplastic primary vitreous (PHPV) or persistent fetal vasculature (PFV). These conditions are characterized by the incomplete disappearance of the hyaloid membrane and can cause visual impairment or even blindness if left untreated.
In conclusion, the hyaloid membrane is a transient structure in the eye that plays a crucial role in the development and maturation of the visual system, providing nourishment and support to the vitreous humor. It undergoes regression during normal development but can give rise to complications if incomplete regression occurs.
• The thin, homogeneous, transparent membrane enveloping the vitreous humor.
• Membrana hyaloidea.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.
The word "hyaloid" is derived from the Greek words "hyalos", meaning "glass", and "eidos", meaning "form" or "shape". The term was coined due to the transparent, glass-like appearance of the hyaloid membrane in the eye. "Membrane", on the other hand, comes from the Latin word "membrana", which means "thin layer" or "film". Therefore, the combination of "hyaloid" and "membrane" refers to the thin, glassy layer found in the eye.