Title: Cherry eye

{{Short description|Prolapse of the tear gland of the third eyelid in animals}}
[[File:Prolapsed gland of the third eyelid.JPG|thumb|Close-up of a cherry eye]]

'''Cherry eye''' is a disorder of the [[nictitating membrane]] (NM), also called the [[third eyelid]], present in the eyes of dogs and cats.&lt;ref name=&quot;autogenerated2000&quot;&gt;Gelatt, K. N. (2000). ''Essentials of Veterinary Ophthalmology''. Baltimore: Lippincott Williams &amp; Wilkins.&lt;/ref&gt; Cherry eye is most often seen in young dogs under the age of two.&lt;ref name=&quot;autogenerated2001&quot;&gt;Gelatt, K. N. (2001). ''Color Atlas of Veterinary Ophthalmology''. Baltimore: Lippincott Williams &amp; Wilkins.&lt;/ref&gt; Common misnomers include adenitis, [[hyperplasia]], adenoma of the gland of the third eyelid; however, cherry eye is not caused by hyperplasia, neoplasia, or primary inflammation.&lt;ref name=&quot;autogenerated1&quot;&gt;Slatter, D. (2001). ''Fundamentals of Veterinary Ophthalmology'': Third Edition. Philadelphia: W.B. Saunders Company.&lt;/ref&gt; In many species, the third eyelid plays an essential role in vision by supplying oxygen and nutrients to the eye via tear production.&lt;ref name=&quot;seniorpetproducts1&quot;&gt;Robledo, E. P., Serrano, R. D., Sanches, N. Q., &amp; Ramirez, A. M. (n.d.). &quot;[http://www.seniorpetproducts.com/pet-vision-study? Effect of Pet Vision in a Canine with Keratoconjunctivitis Sicca (Dry Eye)] {{Webarchive|url=https://web.archive.org/web/20121218053936/http://www.seniorpetproducts.com/pet-vision-study |date=2012-12-18 }}&quot;. Retrieved 1 December 2012.&lt;/ref&gt; Normally, the gland can turn inside-out without detachment.&lt;ref name=&quot;autogenerated1&quot;/&gt; Cherry eye results from a defect in the retinaculum which is responsible for anchoring the gland to the periorbita. This defect causes the gland to [[prolapse]] and protrude from the eye as a red fleshy mass.&lt;ref name=&quot;autogenerated1&quot;/&gt; Problems arise as sensitive tissue dries out and is subjected to external trauma&lt;ref name=&quot;autogenerated1&quot;/&gt; Exposure of the tissue often results in secondary inflammation, swelling, or infection.&lt;ref name=&quot;autogenerated1&quot;/&gt; If left untreated, this condition can lead to [[dry eye syndrome]] and other complications.&lt;ref name=&quot;seniorpetproducts1&quot;/&gt;

==Description==
[[File:Beagle–Cocker Spaniel Mix with cherry eye.jpg|thumb|Beagle-cocker spaniel mix with cherry eye]]
Cherry eye is most common in young dogs, especially breeds such as [[Beagle]], [[Cavalier King Charles Spaniel]], [[English Bulldog]], [[Lhasa Apso]], [[Shih Tzu]], [[West Highland White Terrier]], [[Pug]], [[Bloodhound]], [[American Cocker Spaniel]], and [[Boston Terrier]].&lt;ref name=&quot;autogenerated2000&quot;/&gt; Cherry eye is rare in felines, but can occur. This defect is most common in the [[Burmese cat]]s.&lt;ref name=&quot;autogenerated3&quot;&gt;Griffin, C., &amp; Glaze, M. B. (2008). &quot;Eyes and Ears&quot;. St John U.S.V.I. November 3–6. International Veterinary Seminars.&lt;/ref&gt; A similar condition exists in dwarf lop-eared rabbits, which occurs in the [[harderian gland]]. Similar surgical treatment is necessary.&lt;ref name=&quot;autogenerated1&quot;/&gt;

There is likely a complicated and multigenic component involving genetic risk factors.&lt;ref&gt;Edelmann, M. L., Miyadera, K., Iwabe, S., &amp; Komáromy, A. M. (2013). Investigating the inheritance of prolapsed nictitating membrane glands in a large canine pedigree. Veterinary ophthalmology, 16(6), 416–422. https://doi.org/10.1111/vop.12015&lt;/ref&gt; Some breeds are considered to be more susceptible to its development than others, including the Bulldog, Boston Terrier, [[Bull Terrier]], Lhasa Apso, Cocker Spaniel, St. Bernard, Shar-pei, Shih Tzu and Poodle &lt;ref&gt;&quot;Common Ocular Problems of Shih Tzu Dogs&quot;. ''[[Canadian Veterinary Journal]]'', Volume 33, 392.&lt;/ref&gt; The NM contains many glands which merge and appear as a single gland.&lt;ref name=&quot;autogenerated80&quot;&gt;Sarma, B. (2010). &quot;Cherry Eye in Dogs. ''Intas Polivet'', 11, pp. 80–81.&lt;/ref&gt; Typically, glands secrete tears for lubrication of the cornea.&lt;ref name=&quot;autogenerated80&quot;/&gt; Lack of anchoring allows the gland to flip up, causing the gland to prolapse. Symptoms include a visible fleshy mass, abnormal tear production, and a discharge or drainage from the eye. Cherry eye is typically diagnosed by examination of the [[conjunctiva]] and [[nictitating membrane]].&lt;ref name=&quot;autogenerated2001&quot;/&gt; The most obvious symptom of cherry eye is a round fleshy mass in the medial [[canthus]] of the eye, similar in appearance to the fruit it is named for.&lt;ref name=&quot;autogenerated80&quot;/&gt; This mass may be unilateral or ''bilateral''. Both eyes may develop cherry eye at different times in the animal's life.&lt;ref name=&quot;autogenerated2000&quot;/&gt; Other symptoms of cherry eye include drainage from the eye and abnormal tear production. Initially, cherry eye results in overproduction of tears, but eventually changes to unsubstantial tear production.&lt;ref name=&quot;autogenerated2000&quot;/&gt;

==Treatment==

===Non-surgical===
Cherry eye, if caught early, can be resolved with a downward diagonal-toward-snout closed-eye massage of the affected eye or occasionally self-corrects alone or with antibiotics and steroids.&lt;ref name=&quot;autogenerated1&quot;/&gt;  Sometimes the prolapse will correct itself with no interference, or with slight physical manual massage manipulation as often as necessary coupled with medication.&lt;ref name=&quot;autogenerated1&quot;/&gt;

===Surgical===
Surgery is the most common means of repairing a cherry eye. Surgery involves gland replacement, not excision, by anchoring the membrane to the orbital rim or using a pocket technique.&lt;ref name=&quot;autogenerated1&quot;/&gt; In severely infected cases, preoperative antibiotics may be necessary by means of antibiotic eye ointment.&lt;ref name=&quot;autogenerated1&quot;/&gt; Removal of the gland was once an acceptable treatment, and made the eye appear completely normal.&lt;ref name=&quot;autogenerated3&quot;/&gt; Despite cosmetic appeal, removal of the gland reduces tear production by 30 percent. Tear production is essential in maintaining and protecting the eye from the external environment.&lt;ref name=&quot;autogenerated3&quot;/&gt; Reduced tear production is especially problematic in breeds of animals predisposed to [[Keratoconjunctivitis sicca]] (KCS), also known as dry eye syndrome. With surgeries performed in this manner, KCS often results later in life.&lt;ref name=&quot;autogenerated1&quot;/&gt;
[[File:Cherry Eye in Small Mixed Breed Dog.jpg|thumb|left|Close-up of prolapsed gland in small breed dog]]
KCS is not common in dogs, affecting one per cent of the dog population.&lt;ref&gt;Blount, W. (n.d.). &quot;[http://wendyblount.com/handouts-disease/ophthalmology/KCS.pdf Dry Eye: More formally known as Keratoconjuntivis Sicca or KCS]&quot;. Retrieved 1 December 2012.&lt;/ref&gt; KCS is a chronic degenerative conjunctivitis that can lead to impaired vision and blindness.&lt;ref name=&quot;autogenerated2001&quot;/&gt; KCS has a wide array of causes including drug toxicity, cherry eye, previous surgery, trauma, and irradiation.&lt;ref name=&quot;autogenerated2001&quot;/&gt; KCS can be treated, but treatment often spans the entirety of the animal's life.&lt;ref name=&quot;autogenerated2001&quot;/&gt;

In contrast to this, several replacement surgical procedures exist to remedy cherry eye.&lt;ref name=&quot;autogenerated2001&quot;/&gt; Replacement of the gland results in lower instances of dry eye later in life.&lt;ref name=&quot;intranictitans228&quot;&gt;Plummer, C., Kallberg, M., Gelatt, K., Gelatt, J., &amp; Barrie, K. P. (2008). &quot;Intranictitans tacking for replacement of prolapsed gland of the third eyelid in dogs&quot;. ''Veterinary Ophthalmology'', pp. 228–233.&lt;/ref&gt; Surgery types are broken into two groups: anchoring procedures and pocket/envelope procedures.&lt;ref name=&quot;autogenerated2000&quot;/&gt; At least 8 surgical techniques currently exist.&lt;ref name=&quot;autogenerated2000&quot;/&gt; In anchoring procedures, the prolapsed gland must be sutured to the periorbital fascia, the [[sclera]], or the base of the [[third eyelid]].&lt;ref name=&quot;autogenerated3&quot;/&gt; In contrast, pocket procedures involve suturing healthy tissue around the prolapsed to enclose and secure it.&lt;ref name=&quot;autogenerated3&quot;/&gt; Each of these techniques may be performed with an anterior or superior approach, depending on which direction of suturing will cause the least complications to the eye.&lt;ref name=&quot;autogenerated3&quot;/&gt;

====Anchoring method====
Originally, the anchoring method involved suturing the gland to the globe. This method was superseded over time due to the risky and difficult nature of the surgery, along with a high rate of recurrence.&lt;ref name=&quot;autogenerated1&quot;/&gt; Anchoring approaches from posterior may disrupt normal fluid excretion.&lt;ref name=&quot;intranictitans228&quot;/&gt; Subsequently, an anterior approach was introduced.&lt;ref name=&quot;intranictitans228&quot;/&gt; Disadvantages of anchoring techniques include restricted mobility of third eyelid, which is essential in the functions of fluid distribution and self-cleaning.&lt;ref name=&quot;intranictitans228&quot;/&gt; New procedures are currently being explored to allow tacking of the NM without restricting movement of the third eyelid.&lt;ref name=&quot;intranictitans228&quot;/&gt; Few studies compare results of surgeries, therefore choosing a procedure is a matter of preference.&lt;ref name=&quot;intranictitans228&quot;/&gt;

====Envelope/pocket method====
The envelope method, often called the pocket technique, requires suturing of tissue around the prolapse, encasing it in a layer of conjunctiva.&lt;ref name=&quot;autogenerated3&quot;/&gt; Pocket techniques are easiest for doctors to learn.&lt;ref name=&quot;autogenerated2000&quot;/&gt; Pocket methods also have anterior and posterior versions. Posterior suturing techniques are the most commonly used because they cause the least complications, with no alterations in tear production.&lt;ref name=&quot;intranictitans228&quot;/&gt; Surgery should only be attempted by experienced surgeons.&lt;ref name=&quot;autogenerated1&quot;/&gt; Inappropriate surgical techniques can result in many complications including cysts on the eye.&lt;ref name=&quot;intranictitans228&quot;/&gt;

==Prognosis==

===Without treatment===
Previously, treatment was thought optional until the role of NM was fully understood.&lt;ref name=&quot;autogenerated2000&quot;/&gt; The NM gland is responsible for 40–50% of tear production.&lt;ref name=&quot;ophthalmologists1&quot;&gt;{{cite web|title=Prolapsed gland of the third eyelid|url=http://www.acvo.org/new/public/common_diseases/cherryeye.shtml|publisher=American College of Veterinary Ophthalmologists|access-date=2017-08-03|archive-url=https://web.archive.org/web/20170804053537/http://www.acvo.org/new/public/common_diseases/cherryeye.shtml|archive-date=2017-08-04|url-status=dead}}&lt;/ref&gt; If exposed for extended periods of time, the gland is at risk for trauma, secondary infection, and reduced tear production.&lt;ref name=&quot;ophthalmologists1&quot;/&gt; Many complications can arise if left untreated: early closed-eye massage manipulation is recommended to prevent inflammation .&lt;ref name=&quot;autogenerated1&quot;/&gt;

===Post treatment===
Postoperative treatment includes antibiotic eye ointment three times daily for two weeks.&lt;ref name=&quot;autogenerated3&quot;/&gt; It is possible to have a relapse of the gland after surgery and require multiple surgeries.&lt;ref name=&quot;autogenerated1&quot;/&gt; With treatment, it is possible for animals to live a normal life.{{cn|date=November 2025}}

==See also==
* [[Conjunctivitis]], commonly referred to as pink eye

==References==
{{reflist}}

==External links==
* [http://www.veterinarypartner.com/Content.plx?P=A&amp;S=0&amp;C=0&amp;A=567 ''Cherry Eye'' from The Pet Health Library]

[[Category:Dog diseases]]
[[Category:Eye diseases]]