What is a thorn and how does it happen?
Scar tissue of the cornea differs from healthy tissue: the fibers in it are arranged chaotically, water is retained between them, calcium salts are sometimes deposited and blood vessels grow. Light passes through such an area scatteredly. Doctors divide opacities according to intensity: a light cloud is visible only upon examination, a spot is noticeable up close, a dense leukoma looks like a white area, visible from the side. The depth is assessed separately: superficial opacities are easier to treat, but end-to-end opacities that involve all layers require transplantation.
- Cloud - delicate translucent cloudiness
- Spot - a denser limited area
- Leukoma - a dense white sore
- Adherent cataract - fused to the iris
- Vascularized - overgrown with blood vessels
- Congenital cataract - a rare option
Reasons
In the first place are infectious corneal ulcers: bacterial, herpetic, fungal, amoebic. A special risk group is people who violate the rules of wearing contact lenses: sleeping in lenses, rinsing with tap water, using expired solution. The second major reason is injuries and burns, primarily chemical ones, in which alkali penetrates into deep layers and destroys tissue in seconds. Opacities remain after keratitis during measles and other infections, after trachoma, with complicated keratoconus and corneal dystrophies, and also as a consequence of eye surgery.
- Corneal ulcers of bacterial and fungal nature
- Herpetic keratitis with frequent relapses
- Chemical and thermal burns
- Penetrating trauma and foreign bodies
- Violations of the rules for wearing contact lenses
- Keratoconus, corneal dystrophy, previous trachoma
Symptoms
The formed thorn in itself does not hurt. The main complaint is decreased vision: from a slight haze to distinguishing only light and shadow, if the haze covers the entire optical zone. Many people note halos and rays around lights at night, strong exposure to sunlight, and the inability to choose glasses that would give clarity. A fresh process, unlike an old scar, is accompanied by pain, photophobia, redness and lacrimation - this is a sign of active keratitis or ulcers that require urgent help. A cosmetic defect is often no less troubling than vision loss.
- Decreased visual acuity of varying degrees
- Halos and glare around light sources
- Increased sensitivity to bright light
- Inability to achieve clarity with glasses
- Visible white spot on the eye
- Pain and redness only during active process
Diagnostics
The ophthalmologist examines the cornea using a slit lamp, determining the depth, density, and location of the opacities relative to the pupil. Visual acuity is checked with maximum correction, including with a hard contact lens: if vision improves noticeably with it, then the retina and optic nerve are fine, and surgery makes sense. When the fundus cannot be examined due to a dense cataract, the condition of the posterior segment is assessed with ultrasound. Additionally, eye parameters are measured, the surface of the cornea is mapped and its sensitivity is checked.
- Slit lamp examination
- Vision test with maximum correction
- Trial hard contact lens
- Ultrasound of the eye with an opaque cornea
- Topography and optical coherence tomography of the cornea
- Assessment of corneal sensitivity and eyelid condition
Treatment
Tactics depend on the depth of the clouding and whether the retina and optic nerve are intact. Surface irregularities are smoothed out with a laser, and the irregular shape of the surface is compensated for by rigid gas-permeable or scleral lenses - often this is enough for good vision without surgery. For deep and penetrating scars, a corneal transplant is performed: completely or layer by layer, replacing only the damaged layers. If the transparent graft does not take root due to severe burns and dryness, keratoprosthesis is used. A cosmetic problem in a blind eye is solved with a colored contact lens. Any drops “for resorption” will not remove a dense cataract.
- Rigid gas permeable and scleral lenses
- Laser smoothing of surface opacities
- Layer-by-layer or end-to-end corneal transplantation
- Keratoprosthesis in severe cases
- Cosmetic contact lens
- Mandatory treatment of the main cause: herpes, dry eyes, eyelid pathology
