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Ocular neuropathic pain, also called corneal neuralgia, is a spectrum of disorders of ocular pain which are caused by damage or disease affecting the nerves.Ocular neuropathic pain is frequently associated with damaged or dysfunctional corneal nerves, [1] but the condition can also be caused by peripheral or centralized sensitization. [2]
Gastric bypass surgery may also cause a vitamin B 12 deficiency from poor absorption. Patients who have nutritional optic neuropathy may notice that colors are not as vivid or bright as before and that the color red is washed out. This normally occurs in both eyes at the same time and is not associated with any eye pain.
Cataract surgery by phacoemulsification is frequently performed under surface anaesthesia. Facial nerve, which supplies the orbicularis oculi muscle, is blocked in addition for intraocular surgeries. Topical anaesthesia is known to cause endothelial and epithelial toxicity, allergy and surface keratopathy. [citation needed]
However, if the eyes are asymmetrically affected, i.e. one eye's optic nerve is more damaged than the other, it will produce an important sign called an afferent pupillary defect. [citation needed] Defective light perception in one eye causes an asymmetrical pupillary constriction reflex called the afferent pupillary defect (APD). [citation needed]
When the cornea dries out it may stick to the eyelid and cause an abrasion when the eye reopens. [11] Exposure keratitis. Chemical injury can occur if cleaning solutions such as povidone-iodine (Betadine), chlorhexidine or alcohol are inadvertently spilt into the eye, for example when the face, neck or shoulder is being prepped for surgery. [4] [1]
Paraformaldehyde can be depolymerized to formaldehyde gas by dry heating [2] and to formaldehyde solution by water in the presence of a base, an acid or heat. The high purity formaldehyde solutions obtained in this way are used as a fixative for microscopy and histology. The resulting formaldehyde gas from dry heating paraformaldehyde is flammable.
[67] [68] At concentrations above 0.1 ppm in air, formaldehyde can irritate the eyes and mucous membranes. [69] Formaldehyde inhaled at this concentration may cause headaches, a burning sensation in the throat, and difficulty breathing, and can trigger or aggravate asthma symptoms. [70] [71] The CDC considers formaldehyde as a systemic poison.
Figure 1.0 - Basic anatomical features of the human eye. Ophthalmic drug administration is the administration of a drug to the eyes, most typically as an eye drop formulation. Topical formulations are used to combat a multitude of diseased states of the eye. These states may include bacterial infections, eye injury, glaucoma, and dry eye. [1]