Anatomy, Physiology, and Pathology of the Organs of Hearing, Vision, and Speech - Shvetsov A.G. 2006

Anatomy, Physiology, and Pathology of the Visual Analyzer
Pathology of the Visual Analyzer
Eye Injuries (Trauma)

Injuries account for more than 10% of all ophthalmic pathologies. The majority of eye injuries (up to 90%) are microtraumas and blunt trauma, while 8% are Burns and 2% are penetrating wounds.

Blunt trauma (contusions) of the Eyeball is accompanied by superficial corneal erosion in 60% of cases. Erosions are associated with pain, lacrimation, and photophobia. However, the primary danger lies in subsequent infection and inflammation of the eroded cornea. Superficial erosions heal without complications within the first 24 hours; deeper erosions often result in corneal opacity and permanent Vision loss, while secondary viral, bacterial, or fungal erosions typically heal with scarring, which severely impairs the Optical Properties of the cornea.

Hemorrhages into the membranes and transparent structures of the eye occur in 80% of blunt eye traumas. If Blood enters the anterior chamber, it can obstruct light transmission, but it usually resolves quickly, especially in children. Massive vitreous Hemorrhage leads to near-total blindness, while partial hemophthalmus causes a significant reduction in visual acuity and the appearance of dark, moving spots in the field of vision. Incomplete absorption leads to blood clot Organization and fibrotic Changes in the vitreous body, which can result in retinal detachment or Atrophy of the eyeball. Retinal hemorrhages are accompanied by a sharp decline in visual function (acuity and visual field), sometimes down to light perception. In children, hemorrhages resolve relatively quickly, whereas in adults, they can lead to dystrophic and atrophic changes in the retina.

Traumatic dislocation of the lens can present as subluxation or complete luxation of the lens into the anterior chamber or the vitreous body. The lens is usually displaced downward from its normal position. This anomaly can be congenital or traumatic in nature. It typically leads to decreased visual acuity and impaired accommodation. The severity of visual impairment depends on the degree of lens displacement. A frequent complication is secondary glaucoma. Subluxation and luxation of the lens are often accompanied by cataract formation due to nutritional disturbances.

Retinal contusions are a constant accompaniment to blunt eye trauma. They are characterized by retinal opacities and other ophthalmoscopic abnormalities, visual field defects and constriction of visual fields to white and other colors, impaired dark adaptation, and sometimes a sharp decline in visual acuity. A common complication of retinal concussion is macular dystrophy, resulting in a severe drop in visual acuity. Cystoid retinal degeneration can lead to retinal detachment.

Avulsion and transection of the Optic nerve due to blunt eye trauma are accompanied by immediate, total blindness. Transection leads to optic nerve atrophy at the optic disc, while avulsion results in the replacement of the disc area with Connective Tissue. Both types of changes are irreversible.

Eye wounds can be penetrating or non-penetrating. The danger of a wound lies primarily in the fact that it is almost always contaminated, making a secondary infectious process highly likely. Wounds affecting the optical media of the eye are always accompanied by a significant reduction in visual acuity.

Complicated penetrating eye wounds carry the risk of scarring, corneal opacities of varying size and density, and other complications of the optical media, as well as transient and eventually permanent elevation of intraocular pressure, leading to glaucoma and subsequent secondary blindness. Eye burns are usually domestic and occur 4 times more frequently in adults than in children. Alkaline burns are the most severe, causing deep necrosis of ocular Tissues. In the first hours and days, these burns may falsely appear mild, but they subsequently manifest with increasing depth and area of damage. The most severe outcomes of burns include dense, vascularized corneal leukomas, and adhesions of the cornea to the eyelids, iris, or lens. Naturally, such lesions cause a dramatic decline in visual function.

In radiation burns of the cornea caused by ultraviolet rays (for example, during arc welding or 'snow blindness' in the mountains), eye redness, blurred vision, and rapidly intensifying pain develop after 4-6 hours, accompanied by a pronounced corneal syndrome (photophobia, lacrimation, blepharospasm, etc.). Vision drops sharply. With prompt, appropriate, and continuous Treatment, the symptoms of the burn disappear within 1-2 days, and vision is fully restored.

Radiation injuries to the eyes occur when they are exposed to electromagnetic waves of various wavelengths:

§ prolonged exposure to intense sources of infrared radiation (metal smelting, glassmaking, blacksmithing, etc.) causes chronic inflammation of the sclera and conjunctiva, gradually leading to 'heat' cataract, while some rays penetrate to the fundus, where they are absorbed by the retinal pigment epithelium and the choroid. This causes a retinal burn, manifesting as photophobia, central scotoma, decreased visual acuity, and macular edema;

§ laser beams, if they strike the retina (due to safety violations when working with lasers), cause damage through thermal burns, resulting in impaired visual function. Prolonged exposure to reflected laser radiation can lead to lens opacification and degenerative changes in the retina;

§ ionizing radiation has a pronounced cataractogenic effect. High doses of radiation can cause corneal erosions and ulcers, as well as conjunctival scarring; radiation-induced retinal damage is rare. Vibration, as an etiological factor of noise-vibration sickness, leads to decreased visual acuity due to weakened accommodation. Constriction of the visual field for white and colored targets, as well as impaired dark adaptation, may also occur.