3144. A stray cat has an ocular dermoid

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LIMBAL-CORNEAL DERMOID  in a cat

An OCULAR DERMOID is a fatty growth with skin parts including hairs located in the eye area.

In this case, the ocular dermoid is located at the temporal limbus, within the sclera and corneal areas.

 It is classified as a 

LIMBAL-CORNEAL DERMOID 

Ocular dermoid - limbal-corneal. (Advised but surgery was not done. Surgical excision can be done using surgical blade No. 11).
https://www.youtube.com/watch?v=5hwuWx4T83I

The cat keeps rubbing his eye as the hairs rubs onto the cornea. The cornea becomes ulcerated and painful.  Tears flow down the sides of the eyes daily, leading ro tear staining and infections.  

SURGICAL TREATMENT - COMPLETE EXCISION

For the general practitioner, the use of

1. Superficial keratectomy using scalpel blade No. 11.

1.1. In this case, pull the globe ventrally using a 5/0 nylon stay suture. To do this, put a stay suture into the dorsal bulbar conjunctiva at around 2 o'clock above the medial canthus.   

1.2  Stab and cut away the dermoid carefully from the cornea.  

2.  Start cutting from the lateral aspect of the dermoid. Undermine the dorsal bulbar conjunctiva and excise the dermoid. For the cornea, excise to a third of the corneal stroma depth and 1 mm of normal corneal tissue circumferentially. Be careful of inadvertent corneal perforation. Anti-inflam not given, if kitten or puppy.

The corneal epithelium is excised (superficial keratectomy). Third eyelid flap covers the cornea. Antibiotic eye drops. Healthy replacement cells will grow. If done well, no corneal scarring. E-collar. 

THE 2ND AND 3RD TREATMENT OPTIONS ARE: 

2. Use electro-surgery. I used the circular loop to slice out the dermoid carefully. 

For the specialist.

3. Non-penetrating lamellar keratectomy using the operating microscope and micro-surgery.

RESEARCH NOTES

What is the normal range of corneal thickness in cats?
An average cornea is between 540 µm and 560 µm. A thick cornea is 565 µm or more, with a very thick cornea being greater than 600 µm

Lamellar keratoplasty is an operation in which diseased corneal tissue is removed and replaced by lamellar corneal tissue from a donor. The procedure is performed either to improve vision (optical keratoplasty) or to provide structural support for the cornea (tectonic keratoplasty).

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A healthy cornea is important for good vision. When there is scarring or corneal disease, it can cause one not to see well. Fortunately, there are advanced corneal surgeries such as Lamellar Keratectomy, DSAEK and DALK that are available at The Eye Associates.

There are several common conditions that affect the most superficial layer of corneal cells, the epithelium. These conditions include recurrent corneal erosion (RCE), band keratopathy, Salzmann’s nodular degeneration and epithelial basement membrane dystrophy (EBMD). These conditions can interfere with vision and even cause significant pain and gritty sensation, due to a rough and irregular ocular surface.

If ocular lubricants fail to improve the pain or vision, a procedure known as Lamellar Keratectomy or LK can be beneficial. After the eye is anesthetized with drops or ointment, Dr. Foster selectively removes the diseased epithelium. A soft contact lens is placed that minimizes discomfort after the procedure. This remains in place until it is removed by Dr. Foster. In a few days, a stronger, healthier cell layer will replace that which was removed. Some scratchiness and irritation is normal for a few days after the procedure until the surface has healed.

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REFERENCE:

Dorsally located corneal dermoid in a cat

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5362890/