Pet eye disease is a common condition among dogs. There are many risk factors that can lead to an eye ulcer in the dog. These factors range from the genetic predisposition of the dog, infections in the eye, trauma, and even cancer in some cases. In most cases, it is common for vets to ask the question “Are you seeing improvement?” This guide will tell you signs a dog eye ulcer is healing so that you can make sure your eyesight gets better quickly.
If your yellow Labrador has been diagnosed with a dog eye ulcer, it can be stressful and scary to know how it will heal. If a vet diagnoses your dog with an eye ulcer, she’s likely to give you a lot of information about what you can do for your dog. Some of this information will include all the symptoms taken care of once the ulcer gets better, but how do you know when and if the ulcer is getting better? One of the earliest signs an eye ulcer is healing in dogs is that the opacity that was caused by the inflammation from the ulcer will become more translucent.
A dog eye ulcer is an open wound, and the best way to tell if it’s healing is to look for signs of healing. If the ulcer is healing, you should see the following:
• The edges of the ulcer are starting to close over.
• The edges of the ulcer are turning from red to pink, then white.
• The cornea surrounding an ulcer has started to heal itself, forming scar tissue that will eventually cover over the ulcer completely.
If your dog has an eye ulcer, you may be concerned about the healing process. Here are some signs that the ulcer is healing:
- The ulcer has a bright red, raised edge or rim. This indicates that it’s actively bleeding and there may be a secondary infection in the area.
- You see pus coming out of the ulcer. This indicates that it’s healing and draining fluid from inside its body.
- The ulcer is no longer weeping as much as it was at first (you might have to use a magnifying glass). This means that it’s not leaking as much fluid as before, which is good news! The only downside is that you’ll probably have to treat your dog for an infection if one is present.
Signs A Dog Eye Ulcer Is Healing
Background: Corneal ulcer could be a major source of distress in small animals, with many contributing agents. In recent years, few studies evaluated the efficacy of platelet-rich plasma (PRP) in healing corneal ulcers.
Aim: This study aimed to assess the ability of subconjunctival injection of autologous PRP in the treatment of corneal ulcers in dogs and cats as well as estimate the expression of matrix metalloproteinase (MMP)-2, MMP-9, and oxidative stress biomarkers in these patients.
Methods: A total number of 28 animals (16 cats and 12 dogs) were enrolled in this study. Each animal was subjected to clinical, neurologic, and ophthalmic examinations where the type of ulcer was documented. Tear samples were collected for evaluation of oxidative biomarkers and MMPs; conjunctival swabs were taken to identify the involved organism. PRP was prepared from each animal and given as subconjunctival injection; numbers of injections were done according to case response. Clinical follow-up was done and documented for each case.
Results: In cat patients, female and Persian cats were most affected; unilateral and superficial ulcers were most recorded. In male dogs, unilateral, and superficial ulcers were most recorded. FHV-1 was most identified in cats, while Staphylococcus aureus was most identified in dogs. Numbers of injections needed to achieve healing were recorded, with 50% of dogs needing two injections with 1-week intervals and 50% of cats needed three injections with 1-week intervals. Alterations in both oxidative biomarkers and MMPs were recorded in affected animals.
Conclusion: The use of autologous PRP as a subconjunctival injection in treating corneal ulcers in dogs and cats is effective. The number of injections is the case and corneal ulcer type-dependent.
Clinical Significance: Autologous PRP as a subconjunctival injection in treating corneal ulcer is a relatively cheap, safe method and can be done in the clinical setting.
Introduction
Corneal ulceration is defined as a defect in the epithelium with stromal loss and/or inflammation (1). Corneal ulcers can cause a great deal of discomfort in patients, and it was accounted for up to 0.80% of conditions diagnosed in primary care practice in the UK (2). Contributing etiologies for this condition are numerous; trauma, bacterial or fungal infection, and immune-mediated diseases are the most reported causes (3).
In human medicine, extensive researches were conducted to treat corneal ulceration; recently, trials with platelet-rich plasma (PRP) were performed to assess its efficacy in healing corneal ulcers (4). These trials were conducted after promising findings were recorded in experimental animals (1, 5).
PRP, an autologous byproduct of blood that is very rich in platelets, earned wide recognition for its ability to heal various conditions (6, 7). As late as 1990, the term “regenerative medicine” was recognized (8). Platelets contain growth factors, cytokines, and integrins; these factors contribute to the proposed healing ability of PRP (9). The use of PRP is deemed convenient, cost-effective, non-immune provocation, and minimally invasive technique; the ability to administer it shortly after collection and preparation is an added merit (7). PRP can give essential components for the regeneration of tissue as scaffolds and growth factors (9).
PRP is rich in platelets, which are important for wound healing; they are rapidly deployed for injury sites, stick to it, and generate healing via releasing of numerous growth factors and cytokines (10). PRP was used successfully in treating dormant ulcers (11) and corneal epithelium defects following infectious keratitis (10). In human medicine, PRP was used extensively in the field of orthopedics, plastic, oral, and cardiovascular surgeries (11).
Matrix metalloproteinase (MMPs), a group of zinc-reliant extra-cellular endoproteinase, was postulated to play an integral role in corneal ulcer pathogenesis (12). MMP-2 and MMP-9 are thought to be the primary degrading enzymatic byproducts of corneal fibroblast and epithelial tissue (13, 14). MMPs catalyze basement membrane cleavage components (15). MMP-2 and MMP-9 were elevated in tears of patients with corneal diseases (16).
A strong refractive lens is supported by a combination of the corneal and precorneal tear film. In normal wear and tear mechanism, corneal extracellular matrix (ECM) is stabilized by a balance between collagen and ECM synthesis and their degradation by proteinases, which keep surveillance, remodel, and elimination of damaged corneal epithelial cells, and the abnormal component of ECM (15, 17, 18). These proteinases include MMPs, serine proteases, aspartic proteinases, and cysteine proteinases that exist in latent forms in normal conditions followed by activation during inflammation (13, 18–20). Both MMPs and serine proteinases play an important role in the normal and diseased corneal metabolism of human beings and animals (18, 21). MMPs play a vital role in all stages of wound healing and remodeling, and their overexpression results in excessive ECM degradation, which leads to tissue destruction and loss of visual function (22). MMPs are zinc-dependent enzymes that are classified according to their substrate into gelatinases, collagenases, stromelysins, and membrane-type MMPs (18). Gelatinases, such as MMP-2 and MMP-9, represent activity against collagen degradation products as well as against collagen types IV and V (15, 23). These proteases are mostly the predominant proteinases that are overexpressed in corneal ulceration in comparison with antiproteinases; tissue inhibitors of metalloproteinases (TIMPs) result in rapid degradation of collagen and other corneal ECM (15, 21).
Oxidative stress was described in numerous diseases in pet animal practice; both infectious and non-infectious etiologies were associated with damaging effects of oxidative stress mechanisms (24).
The state of elevated oxidant byproduct and reduction of antioxidant counterparts is known as oxidative stress (24). Malondialdehyde (MDA) is a lipid peroxidation byproduct that is usually measured to evaluate the oxidant arm in the body (25), while total antioxidant capacity (TAC) is used to crude estimate the status of the antioxidant system in the body (26).
This study aimed to assess the ability of subconjunctival injection of autologous PRP in the treatment of corneal ulcers in dogs and cats as well as estimate expression of MMP-2 and 9 and oxidative stress biomarkers in these patients.
Materials and Methods
Study Population, Clinical Examination, and Inclusion Criteria
This study was approved by the Animal Use and Care Committee at the Faculty of Veterinary Medicine, Cairo University, Egypt. A total number of 28 animals (16 cats and 12 dogs) were enrolled in this study. Animals were presented to the small animal clinics, faculty of veterinary medicine, Cairo University, and private clinics in the Cairo governorate. The corneal ulcer was documented at the time of admission, and verbal consent was given from animals’ owners to participate in this study. Each animal was subjected to clinical examination, and signs were recorded at the time of admission.
The lack of previous medical/surgical interference of ulcer, at least 2 months of age, a clear definition of the morphological type of ulcer, and absence of other local or systemic illness were used as inclusion criteria in this study.
Neurologic assessments of participants include menace response, palpebral, pupillary light, and dazzle reflexes. Ophthalmic examinations in a dark room with magnification and focal light source were performed. Ophthalmic examinations include direct ophthalmoscopy (Welch Allyn®, Skaneateles Falls, NY), the Schirmer tear test (Color Bar™ instrument; EagleVision, Inc., Memphis, TN), applanation tonometry (Tono-Pen® VET; Medtronic SOLAN, North Jacksonville, FL), and fluorescein dye (Fluorets® Chauvin, France) staining were done to suspected cases