Download PDF Parsons' Diseases Of The Eye 21st Edition

Sinopsis

The central nervous system is developed from the neural groove which invaginates to form the neural tube running longitudinally down the dorsal surface of the embryo. At either side from the lateral aspect of the anterior portion of this structure, which is the precursor of the forebrain, a thickening appears at an early stage,(the optic plate) which then grows outwards as a diverticulum towards the surface to form the primary optic vesicle (Tig. 1.1 A and B). From this pair of diverticula from the sides of the forebrain and the mesodermal and ectodermal structures in contact with it, the two eyes develop.
 

After it meets the surface ectoderm, the primary optic vesicle invaginates from below (the optic cup), the line of invagination remaining open for some time as the embryonic fissure (Fig. 1.1C). The inner layer of the cup forms the main structure of the retina, the nerve fibres from which eventually grow backwards towards the brain. Its outer layer remains as a single layer of pigment epithelium; between the two lies a narrow space representing the original optic vesicle; and from its anterior border develop parts of the ciliary body and iris (Fig. 1.1E). At the point where the neural ectoderm meets the surface ectoderm, the latter thickens to form the lens Dials, invaginates to form the lens vesicle (Fig. 1.1C) and then separates to form the lens (Fig 1.1D) The hyaloid artery enters the optic cup through the embryonic fissure and grows forwards to meet the lens, bringing temporary nourishment to the developing structures before it eventually atrophies and disappears; as it does so, its place is taken by a clear jelly (the vitreous) largely secreted by the surrounding neural ectoderm.

Content

1. Anatomy and Physiology
2. Ophthalmic Optics and Refraction
3. Ocular Examination Techniques and Ocular Therapeutics
4. Diseases of the Eye
5. Disorders of Motility
6. Diseases of the Adnexa
7. Systemic Ophthalmology
8. Preventive Ophthalmology
9. Surgical Instruments in Ophthalmology

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