The human eye is a sensory Sensory Neurons which conduct nerve impulses to the central nervous system. Nervous System: Histology organ whose primary function is vision Vision Ophthalmic Exam. The eye has a spheroidal shape and is structured in 3 layers: a supporting outer fibrous Fibrous Fibrocystic Change layer, a middle vascular layer, and an inner neural layer. The eye can also be subdivided into 3 compartments: the anterior, posterior, and vitreous chambers. Surrounding the eyeball itself are the extraocular muscles, the lacrimal apparatus, various nerves and vessels, and the bony structure of the orbit Orbit The orbit is the cavity of the skull in which the eye and its appendages are situated. The orbit is composed of 7 bones and has a pyramidal shape, with its apex pointed posteromedially. The orbital contents comprise the eye, extraocular muscles, 5 cranial nerves, blood vessels, fat, the lacrimal apparatus, among others. Orbit and Extraocular Muscles: Anatomy. Light travels through the compartments of the eye to focus Focus Area of enhancement measuring < 5 mm in diameter Imaging of the Breast on the retina, which is the location where photoreceptors convert the stimulus into a neural impulse that is carried by the optic nerve Optic nerve The 2nd cranial nerve which conveys visual information from the retina to the brain. The nerve carries the axons of the retinal ganglion cells which sort at the optic chiasm and continue via the optic tracts to the brain. The largest projection is to the lateral geniculate nuclei; other targets include the superior colliculi and the suprachiasmatic nuclei. Though known as the second cranial nerve, it is considered part of the central nervous system. The 12 Cranial Nerves: Overview and Functions to the brain Brain The part of central nervous system that is contained within the skull (cranium). Arising from the neural tube, the embryonic brain is comprised of three major parts including prosencephalon (the forebrain); mesencephalon (the midbrain); and rhombencephalon (the hindbrain). The developed brain consists of cerebrum; cerebellum; and other structures in the brain stem. Nervous System: Anatomy, Structure, and Classification. Show
Last updated: Aug 11, 2022 DevelopmentGeneral
Timeline
Embryologic development of the eye Image by Lecturio.Related videosGross AnatomyGeneral characteristicsThe adult eye is a complex organ contained within the orbital cavity (composed of 7 bones). Each eye has multiple layers and chambers and is surrounded by 6 extraocular muscles.
Anatomy of the eye Image by Lecturio.Layers of the eyeThe eye is composed of 3 layers ( fibrous Fibrous Fibrocystic Change, vascular, neural) and a transparent connective tissue Connective tissue Connective tissues originate from embryonic mesenchyme and are present throughout the body except inside the brain and spinal cord. The main function of connective tissues is to provide structural support to organs. Connective tissues consist of cells and an extracellular matrix. Connective Tissue: Histology covering (conjunctiva). Conjunctiva:
Fibrous Fibrous Fibrocystic Change layer:
Vascular layer:
The sphincter muscles of the iris are responsible for constricting (A) and dilating (B) the pupil Pupil The pupil is the space within the eye that permits light to project onto the retina. Anatomically located in front of the lens, the pupil’s size is controlled by the surrounding iris. The pupil provides insight into the function of the central and autonomic nervous systems. Pupil: Physiology and Abnormalities. Image by Lecturio.Neural layer:
Retina: Characteristics of the retina and its layers: Table: Characteristics of the retina and its layers
Chambers of the eye
Diagram of the structure of the limbal region: Related videosNeurovasculatureBlood supplyThe entire arterial supply of the eye is provided by branches of the ophthalmic artery and drained by a system of veins Veins Veins are tubular collections of cells, which transport deoxygenated blood and waste from the capillary beds back to the heart. Veins are classified into 3 types: small veins/venules, medium veins, and large veins. Each type contains 3 primary layers: tunica intima, tunica media, and tunica adventitia. Veins: Histology that unite to form the central vein of the retina.
Arterial supply of the eye Image by Lecturio.Venous drainage of the eye Innervation
Related videosFunctionVision Vision Ophthalmic Exam
Refractive media of the eye
Photoreceptor cells of the retina
Clinical RelevanceDisorders of visual perception Perception The process by which the nature and meaning of sensory stimuli are recognized and interpreted. Psychiatric Assessment
Systemic diseases that affect Affect The feeling-tone accompaniment of an idea or mental representation. It is the most direct psychic derivative of instinct and the psychic representative of the various bodily changes by means of which instincts manifest themselves. Psychiatric Assessment the eye
Miscellaneous disorders of the eye
References
When assessing a client's eye what would you assess first?Assessment of Visual Acuity:
The first part of the eye exam is an assessment of acuity. This can be done with either a standard Snellen hanging wall chart read with the patient standing at a distance of 20 feet or a specially designed pocket card (held at 14 inches).
What are the three layers of the eye?Eye Anatomy and Function. The outer layer of the eyeball is a tough, white, opaque membrane called the sclera (the white of the eye). ... . The middle layer is the choroid. ... . The inner layer is the retina, which lines the back two-thirds of the eyeball.. |