Therapeutic extended wear contact lens for corneal injury in a horse.

The research article discusses the treatment of corneal injury in a yearling Quarter Horse filly using a specially designed therapeutic extended wear contact lens, rather than traditional methods like tarsorrhaphy or covering the cornea with a conjunctival flap. The outcome was successful, contributing to quicker healing and reduced trauma.

Case Study

• The study presents the case of a young filly suffering a corneal perforation on its right eye due to a foreign object. This caused the cornea to become cloudy and grey.
• Upon examination, most of the corneal surface stained after applying Fluorescein, indicating extensive loss of epithelium. A small depressed area was identified as the probable point of perforation.
• Following initial checks including vision and response testing to ensure normal function, the eye was cleansed and treated with neomycin ophthalmic ointment.

Treatment Method

• Rather than resorting to common treatments like temporary tarsorrhaphy (stitching eyelids partly closed to protect the cornea) or a conjunctival flap (transferring conjunctiva to cover corneal defect), a specially designed contact lens was used.
• The chosen lens measured 34mm in diameter and an 18mm radius of curvature, based on the average corneal parameters for horses. It was housed in a saline solution in a sealed glass bottle prior to use.
• It remained in place for six continuous days, during which time various antibiotic treatments were applied daily.

Results

• Within 24 hours of starting the treatment, the horse showed noticeable improvement, including reduced corneal haze. After six days, the lens was removed and the cornea showed significant healing with minimal scarring.
• No fluorescein staining occurred, indicating that the epithelium had fully healed. The only visible abnormality in inspection was a small corneal scar.
• The lens was then cleaned, bathed in saline solution, and autoclaved for future use. Examination after one year revealed that even the scar had reduced in size.

Concluding Analysis

• The research points out the benefits of using hydrophilic lenses in equine corneal injury treatment. Acting as reservoirs for topically applied medication, they enhance corneal contact time and act as a bandage to fortify the cornea and promote healing.
• This approach also reduces trauma from the eyelids, potentially reducing pain.
• From this case, the researchers suggest that contact lenses could be a viable alternative to traditional treatments for equine corneal injuries, mirroring their successful use in human ophthalmic care for conditions like keratoconus, aphakia, keratitis, and bullous keratopathy.