Effect of Pet Vision in a Canine with Keratoconjunctivitis Sicca (Dry Eye)

Effect of PetVision® in a Canine with Keratoconjunctivitis Sicca (Dry Eye)

(An - In Vivo – study)


Emilio Robledo PhD, Rebeca Serrano DVM, Norma Sánchez Q.F.B.

Alberto Ramirez MD


ADER Enterprises, Inc.

12526 High Bluff Drive, Suite 300 San Diego, CA 92130 USA


 

Abstract


PURPOSE:


To test the hypothesis of the  beneficial effects of PetVision® in treating keratoconjunctivitis sicca (KCS), induced by removal of the everted third eyelid (or so-called “nictating membrane” or cherry eyes).

METHODS:


Keratoconjunctivitis sicca (KCS), was diagnosed bilaterally in a dog after removal of the prolapsed gland of the third eyelid (cherry eyes).  PetVision® was applied to the canine’s eyes and aqueous tearing production was measured using the Schimer tear test (STT) before , and several times after the drops were applied.

RESULTS:


Surgical removal/extraction of prolapsed gland of the third eyelid (cherry eyes) resulted in induction of KCS in canine eyes, through the means of the Schirmer tear test (STT) values of <10 mm/min were observed in surgically altered canine eyes.

The topical application of PetVision® resulted in the increase of aqueous tearing production, confirmed by employing Schirmer tear test (STT) measures. 

The canine eyes treated with PetVision® had reduced conjunctivitis and ocular discharge for an effective period of approximately 6 hours.

CONCLUSIONS:


Topical application of PetVision® resulted in the increase in aqueous tearing production; while the degree of conjunctivitis and severity of mucus discharge were decreased in KCS canine eyes treated with PetVision®.

These results indicate PetVision® is an effective and safe treatment for relief of pet eye irritation, dryness and secretion of mucin.


Key words: keratoconjunctivitis sicca (KCS), prolapsed gland of the third eyelid (cherry eyes), Dry eye syndrome and PetVision®.



 


What is prolapsed gland of the Third Eyelid (Cherry Eye)?


The third eyelid is a triangular shaped structure in the inner corners of a dog's eye that partly covers the eye and has the ability to close upward and over the dog’s eyeball. It consists of a t-shaped cartilage and a tear gland on the underside of the eyelid.


The third eyelid is important in protection of the surface of the eye by supplying oxygen and nutrients via tear production.


A prolapsed of the gland occurs when the base of the gland flips up and protrudes visibly above and behind the border of the third eyelid. The prolapsed gland becomes swollen and inflamed. The condition frequently occurs in both eyes and is most common in young large breed dogs.


The condition causes chronic irritation of the conjunctiva and cornea, and if untreated, can lead to keratoconjuntivitis sicca (KCS).


  

Prolapsed Gland of the Third Eyelid (Cherry Eye)

(Produces 30% of canine’s aqueous tears)

 

 

 


What is Keratoconjunctivitis Sicca (KCS-Dry eye)?


A chronic, bilateral desiccation of the conjunctiva and cornea due to inadequate tear volume (aqueous tear-deficient keratoconjunctivitis sicca) or to excessive loss of tears due to accelerated evaporation because of poor tear quality (evaporative keratoconjunctivitis sicca).


Deficient tear production causes chronic irritation of the cornea and conjunctiva resulting in corneal ulcers and eventually corneal scarring and can also result in blindness.

 


 


Keratoconjunctivitis Sicca (KCS) (Dry eye)


A dog displays irritation and discomfort by rubbing their eyes, squinting and being sensitive to light. The eye may appear reddened and inflamed and there may also be a thick mucous type discharge in and around the eye.


In a recent study of dogs with eye problems, an amazing 40% were diagnosed with KCS.


How is KCS diagnosed?


A Schirmer test is performed by using standardized strips of filter paper placed, without topical anesthesia, at the junction between the middle and lateral third of the lower lid. Five millimeters or less of wetting of the paper after 1 min on two successive occasions confirms the diagnosis of aqueous tear-deficient dry eye.


Rarely, severe, advanced, chronic drying may lead to keratinization of the ocular surface or loss of the corneal epithelium resulting in scarring, vascularization, infections, ulceration, and possibly perforation. In these severe cases, significant visual loss usually occurs.



 

The Schirmer test


The Schirmer test procedure


•    Place a Schirmer Tear Test strip between the lower eyelid and the eyeball for 60 seconds.


At the end of the 60-second period, the height of the moistened area is measured.


•    A height of 15 mm or more is normal.

•    A height of 11mm to 14 mm is a borderline result.

•    A height of less than 10 mm is dry.

•    A height less than 5 mm is severely dry.


When Results of the Schirmer test are usually normal, instillation of a small volume of highly concentrated fluorescein can make the tear film visible, revealing an accelerated rate of loss of an intact tear film (tear breakup test).


How is KCS controlled?


Tear stimulants and artificial tear replacements are used to control KCS.


 

PetVision®, lubricating eye drops


Materials and Equipment


Materials


•    2 canine eyes with Keratoconjunctivitis Sicca (KCS-Dry eye)

•    2 droppers of PetVision® with 8 milliliters each dropper (This Ophthalmic solutions are sterile, free from foreign particles and especially prepared for application into the canine eye).

•    Schirmer test kit

•    Fluorescein Ophthalmic solution


Equipment


•    Metallic Ruler

•    Calculator


Methodology


Extraction of Prolapsed gland of the third eyelid (Cherry eyes)


KCS was induced bilaterally in two canine’s eyes by removing the orbital lacrimal glands (OLGs) and the nictitans lacrimal glands (NLGs), as follows:


Conservative Surgery Procedure


 

 

Prolapsed Gland of the Third Eyelid (Cherry Eye)

( Conservative Surgery )


Effect of PetVision® in a Canine with Keratoconjunctivitis Sicca( Dry Eyes )

 

Before application of PetVision®


 

 

The Schirmer test ( R-eye = 9 mm/min, L-eye = 6 mm/min )

 

Application of PetVision®, 2 drop in each eye


After application of PetVision®

The Schirmer test ( R-eye = 28 mm/min, L-eye = 26 mm/min )


 

4 hours after application of PetVision®


( R-eye = 15 mm/min, L-eye = 13 mm/min )


  6 hours after application of PetVision®


 

( R-eye = 12 mm/min, L-eye = 10 mm/min )


RESULTS


Rate Data for reaction of PetVision® in the increment of aqueous tearing production




Exponential graph of the Data Table


 

Lineal graph of the Data Table

(y-axis (mm/min) should be read as a natural logarithm (ln))


 


A correlation between initial results of the Schirmer test and final results of the same test was found in a first order reaction, according with the following mathematical model:


X2  = X1 {e (-) k (Y2 – Y1)}


Where:


X1         Initial results of the Schirmer test

X2            Final results of the Schirmer test

( -) k            Rate Constant

( Y2 - Y1 )    Time (Hours, minutes, secounds,etc ) from the application


NOTE: The rate constant must be calculated in each specific case.  For example the value of the rate constants for this case are:


•    R-eye = 0.1166

•    L-eye = 0.1333




DOSE INFORMATION


Effective dose (ED)


Drop volume of 0.05 milliliters


Median effective dose (ED 50)


A container with 8 milliliters of solution


Effectiveness time of dose


6 hours


Because:


•    A height of 15 mm or more is normal.

•    A height of 11mm to 14 mm is a borderline result.

•    A height of less than 10 mm is dry.

•    A height less than 5 mm is severely dry.


 



Conclusions


The incidence of KCS in the general canine population is unknown, although in one study of 460 dogs, the prevalence was estimated at 35%, with particular predisposition among aged dogs of either sex.

 

The breed with the highest relative prevalence of KCS is the American cocker spaniel (20.6%), whereas the commonly used laboratory dogs such as mixed-breed and beagles have lower prevalence rates of 11.5% and 1.2%, respectively.


The present study has established that topical application of PetVision® independent of any direct effect it may have on lacrimal secretory cells exerts an effect on mucin production.  Thereby, it may contribute to the overall therapeutic effect in its use for the treatment of KCS.

Topical application of PetVision® has resulted in the increment of aqueous tearing production.  The degree of conjunctivitis and severity of mucus discharge were decreased in KCS canine eyes treated with PetVision®.



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