◊ 2-Eyelid ◊
I-CONGENITAL ANOMALIES: -
1-Atresia of the eyelid: -
It is congenital absence of the eyelid.
Complete reconstruction of the eyelid.
Absence of a segment of the full thickness of the eyelid (notching of the eyelid).
Correction is surgical and is recommended if the defect is associated by corneal or conjunctival diseases or for cosmetic reasons.
Congenital tumour-like masses of tissues. Dermoids may affect the eyelids only or extend to the conjunctiva and /or cornea. Numerous long hairs are present on the surface of the dermoid. Dermoids may be pigmented or non-pigmented, single or multiple, and unilateral or bilateral. The long hairs may result in keratitis and conjunctivitis.
Surgical excision is recommended and eyelid defects may require blepharoplastic reconstruction.
It is the fusion of the upper and lower eyelids along the eyelid margin. It is normal in the dog for the first 15 days of life. Delayed opening may leads to infection with staphylococcus resulting in ophthalmia neonatorium.
Hot compresses are applied and the line of fusion is separated by a blunt scissors.
5-Macropalpebral fissure: -
It is abnormally large palpebral fissure, which expose the cornea and sclera. This exposure affects the tear film dynamics and predisposes to proptosis.
Lateral or medial permanent tarsorhaphy is recommended.
6-Micropalpebral fissure: -
It is abnormally narrow or small palpebral fissure.
The treatment is not indicated in uncomplicated cases with entropion. Canthoplasty may correct the condition.
II-CONGENITAL OR ACQUIRED AFFECTIONS: -
Trichiasis is a condition in which the cilia arising from normal sites are directed toward the eye and contact the cornea and conjunct. The follicle of the cilia is normally placed, but the direction of growth is toward the eye rather than away. Trichiasis is common in dogs specially Cocker Spaniels and Poodles, but rare in other domestic animals. Trichiasis is congenital but may be acquired following injury to the eyelid. Also it may occur with prominent nasal folds especially in Pekingese and Pugs, entropion, dermoids and blepharospasm.
1-Presence of abnormally directed cilia towards the eyeball.
Pain associated with constant irritation of the cornea and conjunctiva resulting in blepharospasm and rubbing of the eye.
Excess tearing and staining of the facial hairs is present. The lacrimal puncta and nasolacrimal duct should be flushed to eliminate blockage as a cause. Epiphora is often present from early age, and this help to differentiate cilia disorders from other conditions causing epiphora.
4-Chronic conjunctival erythema
The conjunctival blood vessels are engorged with blood.
Ulcers caused by cilia are usually shallow and eccentrically placed on the cornea corresponding to the position of cilia.
If the cilia are few in number, they may be pulled. A special cilia forceps works best for such cases. The process is repeated every few weeks, since the lashes grow back.
2- Electroepilation by using a buttery electrolysis
Low current 2-3 milliampers is used. Excessive current will result in scarring of the eyelid. Insert the needle along the root of the lash and keep it there until the lash is free or cling to the needle and be extracted during its withdrawal.
3-Operation for entropion
Removal of nasal fold when the hair at the nasal fold irritate the cornea and conjunctiva.
4-Surgical removal of dermoids when the hair over it irritate the eyeball.
Presence of a second abnormal row of eyelashes. The cilia originate from abnormally located follicles, which emerge from or just posterior to the openings of the meibomian glands. The condition is congenital and probably inherited in dogs. All breeds are affected, but it most commonly occurs in Cocker Spaniel, Pekingese and Poodles. Distichiasis can be observed in animals of all ages, indicating that the ingrown lash may be present for years before it penetrates the conjunctiva. Distichiasis are rarely seen in other domestic animals.
3- Keratitis and corneal ulceration.
4- Presence of abnormal cilia. Distichia are usually multiple (from 5-40 cilia) and difficult to seen as they are thin and lightly pigmented. Magnification and source of illumination with eversion of the lid margin facilitate detection of distichia. Sometimes multiple eyelashes can be seen emerging from a single follicle (districhiasis).
1-Epilation by cilia forceps
It can be performed under topical anesthesia. The lashes will grow back within several weeks.
Electrolysis destroys the follicle permanently. The procedure is performed under magnification and illumination. It is tedious if cilia are numerous. The needle is introduced 2-3 mm along the cilia for 5-30 second. Low current minimize tissue destruction and prevents twitching of orbicularis oculi muscle. Commercial battery powered epilation unites are available.
Resection of the cilia-bearing conjunctiva provides more satisfactory results than electroepilation. The number and position of distichia determine the extent and location of surgical sites.
The lid is held with fixation forceps or chalazion clamp. The lid is split at the level of the meibomian gland orifices into 2 layers; tarso-conjunctival and orbicularis-skin. The depth of scalpel or razor blade is about 2 mm. This is enough to reach the tarsus and include the distichia. The base of cilia-bearing strip of tarso- conjunctiva is excised by small scissors. Haemorrhage is controlled with topical epinephrine 1:10.000 solution. No sutures are required and healing by granulation is complete by two weeks. Topical antibiotic-corticosteroids for 5-7 days are administered.
4-Removal of a V- shaped segment of the tarso-conjunctiva containing distichia
The resultant defect may then be filled with sliding graft of tarso-conjunctival or left to granulate.
5-Various entropion surgical techniques may be used to treat distichiasis
It can be performed by everting the eyelid margin, thereby redirecting the distichia away from the eyeball.
3-Ectopic cilia: -
Ectopic cilia means single or multiple cilia are emerging from the conjunctival surface of the eyelid. The condition is congenital and observed after several months to several years of age. It is evident that while aberrant follicles may be present at birth, the problem is not clear until the cilia grow and penetrate the conjunctival surface
1-Presence of ectopic cilia at the palpebral conjunctiva, 2-6 mm from the lid margin
2-Ectopic cilia usually develop from an elevated area of the palpebral conjunctiva, which may be hypopigmented or hyperpigmented.
3-Blepharospasm and epiphora.
4-Conjunctivitis especially at the bulbar conjunctiva
5-Vascularization of adjacent parts of the cornea accompanied by an elongated superficial corneal ulcer
1-Electroepilation of ectopic cilia
2-Surgical removal of the cilia with part of tarso-conjunctiva containing the follicle
4-Chalazion - Meibomian cyst - Tarsal cyst: -
It is an enlargement of the meibomian gland caused by blockage of its duct
1-Localized painless swelling and yellow-white in color when viewed through the palpebral conjunctiva
2-The size of the swelling varies between a pea-like swelling in dogs to a hazel-nut in horses
3-Chalazion is few millimeters from the lid margin
4-Chalazion bulges the skin over it but still the skin is freely movable
5-The conjunctiva over the chalazion is reddened and elevated
6-The contents arc usually cheesy inspissated oily secretion
- Chalazion clamp is applied to the eyelid and then everted
- Incision is made through the conjunctiva over the swelling
- The contents are squeezed and the wall of the chalazion is thoroughly curetted.
- The clamp is removed and antibiotic ointment is applied for several days.
5-Hordeotum - Stye: -
Hordedum is an acute localized suppurative inflammation of the glands of Zies and glands of Moll belonging to the follicle of the eyelashes. Hordeolum affecting glands of Zies and Moll usually termed external hordeolum, while that affecting meibomian gland (meibomitis) is termed as internal hordeolum. The microorganism is usually staphylococcus.
1- Small solitary abscess or multiple abscesses at the lid margin
2- Blepharitis, blepharospasm and epiphora
3- The condition is painful
4- Internal hordeolum is characterized by presence of small painful abscess at the inner surface of the eyelid near the lid margin
-Pulling of the offending eyelash (epilation) which present at the apex of the swelling.
-Softening of the skin over the abscess by hot compresses contains sodium bicarbonate.
-Incision of the abscess and evacuation of its content
-Rubbing of antibiotic ointment to the lid margin
-Systemic antibiotic may be indicated
-If there are recurrences, injection of staphylococcus toxoid is of value
Entropion means turning-in or inversion of the eyelid margin.
Entropion can be classified by etiology into two groups:
A-Congenital entropion: -
It occurs most frequently in dogs, horses and sheep. Congenital entropion may occur sporadically or may be inherited as an autosomal dominant trait in some breeds of dogs. Different anatomic components of entropion are characteristic for each breed of dogs. As example, lateral canthal entropion is common in large and giant breeds of dogs (St. Bernard and New Foundland), entropion at the lateral two-thirds of the lower eyelid is common in Bulldog and medial lower lid entropion is exhibited in the Toy and Miniature Poodle. Also entropion may be accompanied with micro-palpebral fissure in the Chow Chow, with distichiasis in St. Bernard and Cocker Spaniel and with enophthalmia in Doberman and Great Dane.
B-Acquired entropion: -
i-Spastic entropion: -
Chronic irritation of the conjunctiva (Follicular conjunctivitis) initiates the spasm of orbicularis oculi muscle. Contineous blepharospasm tends to accentuate lid margin inversion; the resulting trichiasis increases irritation and a cycle of increases irritation and increasing severity of blepharospasm occurs with end result of spastic entropion.
Auriculopalpebral nerve block will relieve and define the blepharospastic component of entropion.
ii-Cicatrical entropion: -
It occurs due to fibrosis and contraction associated with surgery or trauma of the conjunctiva. Also chronic inflammatory process of the conjunctiva can produce cicatrical entropion
iii-Bulbar entropion: -
Usually resulting from enophthalmos, microophthalmos, atrophy of the globe and enucleation of the eyeball
1-Epiphora, photophobia, and bl»ipharospasm
2-Conjunctivitis with purulent discharge in chronic cases
3-Corneal ulceration and vascularization
4-Inversion of the lid margin with trichiasis
Entropion is generally a surgical problem, the technique of correction is determined by the cause, location, and extent of entropion.
A-Mild cases in young animals: -
It may be managed medically until maturity for complete facial development and to avoid risk of anesthesia. Different techniques for correction of entropion have been reported:
1-Suture technique: -
The edge of the eyelid is retracted with 3-4 vertical mattress sutures that are left in place for 7-10 days. This is the treatment of choice in foals.
2-Injection technique: -
Various materials are injected into the lower lid to tense it and cause eversion. Procaine penicillin, melted paraffin wax, or even sterile air (5-15 ml) is effective in many cases, (injection of air from the sheep yard may leads to infection, with spores of clostridium tetani). This technique is used mainly in lambs.
3-Stapling technique: -
Stapling of an elliptical segment of skin with paper stapler can be used in lambs.
4-Cautery puncture: -
It is effective in mild cases in dogs. The skin of the eyelid in penetrated with a blunt pointed electrode or well-heated strabismus hook. These punctures in one or two rows are 4-5 mm from the lid margin and extends through the tissues and not through the palpebral conjunctiva. The resultant cicaterization ended with correction.
B-Surgical treatment of severe cases or in mature animals: -
1-Elliptical skin resection technique: -
The initial skin incision is made parallel to and 2-3 mm from the lid margin (in dogs) to a depth that includes the orbicularis oculi muscle. The length of incision is determined by the length of inverted eyelid margin. The second elliptical incision is performed below the first one and join it at both ends. The width of skin flap will depends on the amount of entropion. The incised area of skin is elevated and excised by scalpel or scissors. Haemorrhage is controlled with digital pressure or with topical application of epinephrine 1/10.000- 1/100.000. Suture the wound with 4/0 nonabsorbable simple interrupted sutures. The sutures are removed 10-14 days after surgery.
2-Trephine technique: -
A local area of skin is removed with a dermal punch, resulting in a defect that is circular, then sutured horizontally. This technique is effective in cases of entropion affecting small area of the lid or in cases of entropion affecting both the upper and lower eyelid at the lateral canthus.
3-Pinch technique: -
Pair of curved Mosquito forceps is placed on a fold of skin 2-3 mm from the lid margin and parallel to it. The amount of skin depends on the degree of entropion and can be estimated before application of forceps by using toothed tissue forceps. The haemostats are closed and the skin is crushed between the jaws and then the haemostats are removed. The strip of skin is grasped and excised by scissors. The wound is carefully sutured with simple interrupted sutures of 4/0 silk. The sutures are removed after 14 days. The pinch technique can be considered the technique of choice for correction of entropion in dogs and cats and can be adopted in mild and severe cases. The resected areas should correspond in location and extent to the affected portion of lid.
4-Lateral canthoplasty: -
In some breeds of dogs namely Chow Chow, English Bulldog, Golden Retriever and St. Bernard, there is a combination of ectropion at the central portion of the lower eyelid and entropion at the medial and lateral portions of the eyelid. This condition is accompanied by a round lateral palpebral fissure. This problem is due to poorly functional lateral retractor muscle and week lateral canthal ligament. A Y-shaped incision is made at the lateral canthus and the arms of the Y extend superiorly and inferiorly over the upper and lower eyelids. The skin surrounding the Y is undermined and the orbicularis oculi muscle is exposed. A superior and inferior strips of orbicularis oculi muscle are dissected free with their base attached at the lateral canthus. The two strips are united with single suture of 2-0 silk in a figure-of- eight pattern, then grasped and anchored firmly to the periostium of the zygomatic arch at a location that restores normal confirmation of the palpebral fissure. A modification for fixation of the suture material to the strips of orbicularis muscle is suggested by using double needles thread. One needle traverse the upper strip from its base to the apex and the second needle traverse the lower strip also from the common base to the apex. The two needles with the thread are grasped laterally to the periosteum of the zygomatic arch. The skin incision is routinely closed.
Ectropion is an eversion, out rolling, or turning out of the eyelid margin. The lower eyelid is most commonly involved. It is common in dogs and rare in cats and other domestic animals.
Ectropion is classified according to the cause into:
A-Congenital ectropion: -
This type is usually breed associated in dogs with loose face skin e.g., Saint Bernard, Bloodhound and Cocker Spaniel.
B-Acquired ectropion: -
i-Senile ectropion: -
It ensues due to decreased tone of orbicularis oculi muscle. It is atonic variety characterized by elongation of the lower lid, lack of good muscle tone, eversion and drooping of the lower eyelid.
ii-Cicatrical ectropion: -
It ensues due to retraction of the lower eyelid by contraction of scar tissue secondary to surgery, trauma, thermal and chemical injuries or chronic inflammation.
iii-Intermittent ectropion: -
It can be seen in some hunting dogs that develop physiological ectropion due to fatigue of facial muscles. These dogs look normal at morning and have ectropion by evening.
1-Eversion of the eyelid, abnormally exposes the palpebral and bulbar conjunctiva and cornea. This may results in conjunctiva! and/or corneal disease.
2-The degree of ectropion varies markedly from just slight ectropion of the medial or middle part of the lower eyelid to complete ectropion of the entire lower eyelid.
3-Marked ectropion may leads to marked epiphora, keratinization, hypertrophy of the conjunctiva, and exposure keratitis due to faulty eyelid closure.
Ectropion should be corrected surgically when it results in secondary conjunctival or cornea! disease e.g. conjunctivitis, corneal vascularization or pigmentation and exfoliative blepharitis due to epiphora. Cicatrical ectropion usually results in unsightly cosmetic defects, which justify correction even without presence of ocular lesions. Many techniques have been used to correct different types of ectropion.
Small areas of. electrocautery are performed on the conjunctival side of the everted eyelid to create an area of scar tissue with resultant contraction of the eyelid. The electrocautery or heated muscle hook is thrust through the palpebral conjunctiva in. a parallel line about 4-5 mm from the lid margin. The technique has proved very unreliable as the degree of contraction and scaring is impossible to estimate.
It is the removal of a small horizontal piece of conjunctiva at the level of the area of ectropion. It may be done alone or in combination with oilier procedures. The conjunctiva is grasped with tine forceps, elevated, and clamped with mosquito artery forceps for one minute. Then the caimp is removed and the elevated ridge of tissue is excised with tenotomy scissors. The conjunctiva is closed with simple continuous suture. Again, the technique has not proved reliable especially in cases of marked eyelid laxity.
3- Skin trephination:
It is used for mild ectropion, especially when only a portion of the lid margin is affected. Several small circles of skin (2-4) are removed with skin biopsy punch (5-7 mm diameter), 3-5 mm from the lid margin. The edges are sutured in a vertical manner using 4/0-6/0 with eyeless needle in simple interrupted pattern.
This technique is effective in case of moderate congenital or 'senile ectropion when the lower eyelid is too much elongated.
-The eyelid is split into skin-orbicularis and tarso-conjunctival layers
-A V-shaped tarsoconjunctival wedge is removed medially
-A similar V-shaped wedge of skin and orbicularis oculi muscle excised, 5-10 mm lateral to the level of the tarsoconjunctival one
-The two V-shaped wounds are closed independently with simple interrupted stitches
-Additional sutures of fine absorbable suture materials are used at the lid margin to re-appose the skin-orbicularis muscle and tarso-conjunctival layers
-This technique is used in advanced cases of congenital and senile ectropion when more pronounced elongation of the eyelid is present.
-The lateral one-half of the lower eyelid is split into skin-orbicularis oculi muscle and tarso-conjunctival layers to a depth of 20 mm.
-A wedge shape of the tarso-conjunctival layer is excised. The skin incision is continued laterally, following the natural curve of the lower eyelid, for one cm. from the lateral canthus.
-The skin-orbicularis muscle flap is separated by blunt dissection to provide a lateral movement of the flap
-A wedge of the sliding skin-muscle flap is excised at its lateral margin
-The tarso-conjunctival and skin-orbicularis muscle wounds are sutured and the edges of the lid margin are apposed as mentioned before.
6-Full thickness eyelid resection at the lateral canthus:
-This method is suitable for congenital and senile ectropion with moderate elongation of the lower eyelid. It is essentially a full thickness resection of the eyelid similar to that used for tumour removal.
-The edge of the eyelid is notched 3-4 mm from the lateral canthus with mosquito artery forceps. The actual lateral canthus is avoided because the eyelid is much thicker at the canthus than it is where the tarsal glands are present.
-The excess length is estimated and the eyelid is notched again by another Mosquito artery forceps to determine the length of the part of eyelid to be resected.
-A scissors are used to cut the eyelid at the notch near the lateral canthus for about one cm. The cut edge is grasped until the eyelid is tense.
-The overlapping portion of eyelid estimated before, is removed by a scissors in a form of a V-shaped flap
-The V-shaped wound is closed; the tarso-conjunctival layer then the skin-orbicularis oculi layer as the same manner of eyelid laceration.
7-Full thickness resection at the middle of the eyelid:
-This technique is used when ectropion is accompanied by scarring or deformity at the central area of the lid margin.
-Stretching of the eyelid from the lateral canthus will not correct the lesion and therefore a central technique must be used.
-The technique is basically the same as described for full resection at the lateral canthus. In some cases the palpebral conjunctiva is left intact and the eyelid is incised to the level of meibomian gland, then complete triangle of the skin is removed.
8-V-Y blepharoplasty (Wharton-Jones blepharoplasty):
-This technique is used basically to correct cicatrical ectropion. Most cases of cicatrical ectropion are associated with scar formation from bite wound or other forms of trauma. The cicatrical ectropion is differs from senile and congenital types is that instead of too much tissue being present in the later, there is loss of tissue in cicatrical one. The aim of surgical procedure is to free the skin from the underlying scar and allow the lid to return back to its normal position.
-A V-shape skin incision is made including the scar
-The skin flap-is freed from the underlying scar tissue by blunt scissors dissection and the scar tissue is excised. The skin flap is moved upward to correct the eyelid margin.
-Undermine the skin at the apex of the "V".
-Close the defect in a "Y" shaped pattern to cover the bared are of skin with simple interrupted suture. |
Complication of ectropion surgery:
1-Undercorrection have been most prevalent when a lid shortening procedure without lid elevation is used and sagging of the lower eyelid continues.
2-Overcorrection can result if too much eyelid tissue is removed with resultant entropion development.
3- Excessive shortening of the palpebral fissure may result when to much full thickness wedge resection is removed.
Blepharitis is a general term describing inflammation of the eyelids.
1-According to the cause blepharitis is classified into, bacterial, mycotic, parasitis, allergic, traumatic and neoplastic.
2-From the pathological point of view, blepharitis is classified into superficial which results from dermatitis, conjunctivitis, hordeolum, chalazion or irritation by mange and deep blepharitis which results from a bite or deep lacerating wound.
3-Clinically, acute, subacute or chronic; and granulomatous or nongranulmatous blepharitis can be differentiated.
4-Blepharitis may be focal or diffuse, unilateral or bilateral and may involve the upper and/or the lower eyelids.
1-Pain manifested by blepharospasm.
2-Hyperaemia and swelling of the eyelid due to edema or inflammatory cell infiltration.
3-Alopecia, Scalpess, pruritis, and epiphora
4-Serous or purulent exudation
5-Ulceration and fibrosis specially in chronic cases
1-Careful cleaning of the lid margins and removal of purulent exudates with cotton soaked with worm normal saline or 2% sodium bicarbonate solution.
2-Topical application of antibiotic ointments to the outer and inner lid margin
3-Systemic antibiotics can be described in acute cases
4- Topical fungicide is, used in cases of fungal blepharitis
5- In parasitic blepharitis a protective ointment is applied to the lid
6- Corticosteroids and antihistamines are indicated in cases of allergic blepharitis.
9-Ptosis or Blepharoptosis: -
Means drooping of the upper eyelid. Ptosis is classified according to the cause into:
As in cases of enophthalmia or atrophy of the globe
B- Acquired ptosis:
As a result of trauma of the eyelid, abscess or tumor of the eyelid; or fracture of the supraorbital process
It may be central as a result of cerebral or cerebellar tumor or peripheral due to paralysis of the nerve supply of the levators of the eyelid. Oculomotor nerve supply the inner levator of the upper eyelid (levator palpebrae superioris) and the facial nerve supply the outer levator of the upper eyelid (corrigator supercilii).
1- Resection of the levator muscles of the upper eyelid.
2- Removal of an elliptical piece of skin or trephination of a circular disc and suturing the wound horizontally.
10-Traumatic eyelid injuries: -
Most traumatic injuries of the eyelids are mechanical in origin. In large animals; nails, hooks and barbed wire are responsible for eyelid wounds and lacerations. In small animals, injuries mainly are due to animal bites or cat scratches. Injuries are classified clinically into those that involve the skin only and those involve the full thickness of the eyelid. The tear is parallel or perpendicular to the lid margin. Considerable haemorrhage is observed with epiphora and blepharospasm. The eyelids are highly vascular structures and have a remarkable ability for healing and resistance to infection. Nearly complete avulsed eyelid can be successfully repaired simply by suturing it back into proper position directly after injury.
1-Copious irrigation and cleaning of the wound with boric acid solution 2% or warm normal saline.
2-Removal of any blood coagulum or foreign body
3- Minimal debridement of the wound
4-Suturing of the wound to restore the anatomic and functional integrity of the eyelid. In full thickness injury two-layers closure is the technique of choice. Tarso-conjunctival with absorbable suture material and orbicularis-skin with non-absorbable suture material. The lacrimal punctum and canaliculus should be identified and preserved as much as possible.
5-Protective neck collar is applied and taping of dew claws
1-Epiphora due to distortion of the puncta lacrimalis
2-Entropion or ectropion
These complications can be corrected latter on as a secondary procedure following complete healing of primary wound.
11-Eyelid tumours: -
Eyelid neoplasms are not uncommon in domestic animals specially in dogs. The most common eyelid tumours are:
Dog: -Adenoma, papilloma, melanoma and adenocarcinoma.
Cat: - Squamous cell carcinoma and fibrosarcoma (Sarcoids).
Cattle: - Squamous cell carcinoma.
All eyelid tumours are regarded as malignant until proved otherwise by biopsy examination. The best treatment is combination therapy of two or more of the following methods:
The tumour tissue should be removed as much as possible, including the regional lymph node if affected. Complete surgical excision is not possible in extensively invading neoplasms as squamous cell carcinoma and additional methods are used to destroy remaining cells.
Small tumours involving one-third or less of the lid margin, a full-thickness V-shaped excision technique is indicated.
The lesion and surrounding margin of normal tissue are frozen. The result is death of the cells, necrosis, sloughing and healing by granulation. The temperature of the probe is -25°C and double freeze-thaw cycle is used. Thawing should be up to 20°C. Freezing can be performed by cold probe or by liquid nitrogen. The surrounding structures must be isolated by a surgical sponges impregnated with petroleum jelly. Freezing of tumours increase the antigenicity of the tumour cells and result in increase immunologic response to the tumour.
3- Radiation therapy : The most sensitive tumour to radiation therapy is the squamous cell carcinoma. Gamma radiation is used frequently and may be administered by radon seeds, cesium implants or X-ray therapy machine. Beta radiation is also used and is emitted from strontium 90 ophthalmic applicator. A dose of 4000 to 5000 rads for 7-10 days is suitable for most tumours.
Chemotherapeutic agents are not commonly used for treatment of eyelid tumours, these are alkylating agents, antimetabolites, antibiotics, corticosteriods and enzymes. Such agents are used to reduce the size of tumour before radiation therapy or surgical excision.
Different agents have been used to stimulate the immune system of the animal body against neoplastic cells. These are nonspecific immune stimulants injected intramuscularly to stimulate the entire immune system such as tetramizole, live or killed BCG extracts (for equine sarcoid), Brucella abortus vaccine and specific immune stimulants injected into tumour masses such as BCG and corynebacterium parvurn.
12- Eyelid abscesses: -
In most cases eyelid abscesses are subconjunctival and in some cases subcutaneous. The cause may be penetrating wound, embeded foreign body or hordeolum. Subconjunctival abscesses are present at the lateral canthus, upper eyelid and lower eyelid. The conjunctival abscess swelling extends over the eyeball and protrudes through the palpebral fissure preventing closure of the eyelids. Subcutaneous lid abscess leads to swelling of the eyelid preventing opening of the eyeball.
In subconjunctival abscess, evacuation is performed through a con- junctival incision. After squeezing and flushing of the abscess cavity, antibiotic eye ointment is applied. Subcutaneous lid abscess is drained through a skin incision.