Aqueous humor is an important component of the eye’s optical system. It is a clear fluid that fills the anterior chamber (The space between the cornea and the iris). Both the cornea and the lens must remain clear to support light transmission, therefore, they do not have their own blood supply and that is when the Aqueous humor comes in play to provide nutrition, remove excretory products from metabolism, transport neurotransmitters, stabilize the ocular structure, contributes to the regulation of the homeostasis of these ocular tissues, and provide a colorless and transparent medium between the cornea and the lens.
The Ciliary Body
The ciliary body is the site of aqueous humor production, it is a circular structure just behind the iris composed
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• Pars Plicata: The anterior portion of the ciliary body, have a large surface area and responsible for ciliary processes.
• Pars Plana: The posterior portion of the ciliary body, flat, has a pigmented inner surface and continues to the choroid.
The ciliary body is composed of muscle, vessels and epithelium.
The Ciliary epithelium is a double layer of cells covering the surface of the ciliary body, and has two layers:
1- An inner, Non-pigmented ciliary epithelium: represents the continuation of the retina, comes in contact with aqueous humor in the posterior chamber, the tips or crests of the non-pigmented ciliary epithelia are believed to be the sites of the active secretion of aqueous humor.
2- An external, pigmented ciliary epithelium: comes in contact with the ciliary process stroma.
Ciliary stroma:
Ciliary stroma consists of bundles of loose connective tissue, it contains blood vessels, nerves and ciliary
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In most cases, the damaging pressure is greater than 21 mmHg, however, in some cases damage may occur in a lower pressure (known as normotensive glaucoma), Or on the opposite of that, some people may be able to tolerate higher-than-normal pressures without having any damage in the optic nerves.
Glaucoma is characterized into two categories:
- Open-angle chronic glaucoma is painless, develops slowly over time. It is treated with either glaucoma medication to lower the pressure, or with various pressure-reducing glaucoma surgeries.
- Closed-angle chronic glaucoma: sudden eye pain, redness, nausea, vomiting, and other symptoms resulting from a sudden arise in intraocular pressure, and is treated as a medical emergency.
The pressure of the eye is measured by gently touching the cornea with special instruments to see how hard it is to poke (the less pressure the easier to poke, the more pressure the stiffer). Current Treatments of glaucoma generally aim to lower the intraocular pressure, to do so we must either reduce aqueous humor production or enhance its outflow.
Having diabetes or having a family member with glaucoma may increase the risk factor of
It shows a trachea of the silkworm which carries oxygen from the openings within the surface of its body or spiracles. The tracheal tubes are divided into a branch of
In the eye, the cornea is entry point for light. In simple terms, the cornea is the transparent tissue at the front of the eye that functions as the window through which all light has to pass through on its way to forming visual perception. The reception of a clear image is dependent on the integrity of the corneal surface. However, with age, the lens is subject to cataracts and presbyopia in addition to other damage. This damage to the surface of the eye effects how people see and could potentially slow their reaction time to what they are seeing.
That type of glaucoma can cause vision loss within a day if is not treated as an emergency.4)Secondary glaucoma: type of glaucoma resulting from injury or other eye disease.5) Congenital glaucoma: mostly manifested in children. Most often they were born with a defect in the angle of drainage. Glaucoma suspect: Some people have normal eye pressure, but their optic nerve or visual field looks suspicious for glaucoma.” (Geteyesmart-Journal of American Academy of Ophthalmology) Signs, symptoms and
Introduction Diabetes mellitus is a disease where the sugar levels in one’s blood is above the normal level. This is caused when the body does not produce enough insulin or the body’s cells do not respond correctly to insulin or both. A manifestation of diabetes in the eye is diabetic retinopathy .This affects the retina of the eye. It is when small vessels which are damaged spill into the retina.
[1] In 1965 detailed physiological experiments were performed to know how the types of cones in the eye are functioned. Those experiments confirmed the
You must not be suffering from any auto-immune diseases and there should be no corneal
Morphologic assessment of corneal endothelium by specular microscopy in evaluation of donor corneas for transplantation. Cornea. 1995; 14(6): 554-561. O’Day DM. Donor selection. In: Brightbill FS, ed.
• Most commonly, drugs that lower intraocular pressures are topically delivered as eye drops, and it is reasonable to attempt the same with a neuroprotection therapy. • Many disease treatments are only partly successful as monotherapies; however, when combined with other therapies, the result is often virtual eradication of a
With angle-closure glaucoma the intraocular pressure experiences a sudden increase and has a closed angle between the cornea and iris. Angle-closure is quick developing and is very noticeable compared to open-angle glaucoma that goes fairly unnoticed. Angle-closure glaucoma will need medical attention soon. Some signs of angle-closure glaucoma include nausea, pain, headache, and blurry
Nasal congestion is a feeling of blocked nose that can become a real problem impacting the quality of your life. Such congestion could lead to greater problems if left unattended, especially when the condition persists beyond the normal duration. It is important to understand the underlying conditions that cause congestion of the nose. Some conditions settle down on their own, while others will require some interventions to be alleviated. Nose congestion are usually caused by the inflammation of the thin mucous membranes that line your nasal passage.
It is the only membrane in the body that closes an orifice and remains intact. It is slightly oval shaped, emulates an irregular cone with its apex at the umbo and is obliquely placed. It forms the lateral wall of the tympanic cavity and subtends an angle of about 55° with the inferior wall of the external auditory canal, measuring 9-10 mm (horizontal dimension) x 8-9 mm (vertical dimension).(23) The thickened circumference forms the fibrocartilaginous tympanic annulus anchored in the tympanic sulcus that is deficient superiorly forming the notch of Rivinus. As the tympanomeatal flap is elevated, the annulus is taken along with the TM, and commences just above the notch of Rivinus superiorly.
The fibres first pass in a dorsomedial direction and then loop over the abducent nerve and produce a small round swelling in the floor of the 4th ventricle. The superior salivary and lacrimatory nuclei of the facial nerve are also present in the lower half of the of pons. These nuclei are small collections of cholinergic nerve cells in dorso-lateral reticular formation. The neuron of these two nuclei seems to be intermingled with each other.
The sclera is a dense-fibrous connective tissue extends from the cornea to the optic nerve. The sclera is primarily consisted of avascular lamellae of collagen fibers which is responsible of bearing the Intraocular Pressure (IOP) [1]. Collagen type I is the core components of the sclera and they have to provide the eye with compulsory mechanical strength to be able to bear the IOP as well [2]. Each year above 1.9 million people experience one type of eye injuries in the United States alone [3]. Trauma is one of the most usual ones which as a result of that nearly 30,000 people lost their vision in the United States [4].