Surgical affections of eyeball
Surgical affections of eyeball in animals are Anophthalmia, Exophthalmos, Enophthalmos or pig eye, Hydrophthalmos, Strabismus or squint, Glaucoma, Dermoid cyst etc.
Surgical affections of eyeball
Surgical affections of eyeball in animals are-
- Anophthalmia
- Exophthalmos
- Enophthalmos or pig eye
- Hydrophthalmos
- Strabismus or squint
- Glaucoma
- Dermoid cyst
Anophthalmia

Complete absence of the eye ball (Anophthalmia) in a young dog
Anophthalmia is the complete absence of the eye ball.
Exophthalmos
Exophthalmos is an abnormal protrusion of the eyeball. It may be a congenital condition or may be due to retrobulbar abscess, haematoma, or inflammation.
Exophthalmos may be seen as a symptom of diseases like hydrophthalmos and glaucoma. Exophthalmos due to goiter resulting from iodine deficiency is rare in animals.
Enophthalmos or pig eye
Enophthalmos or pig eye is an abnormal retraction of the eyeball into the orbit.
It may be congenital or sometimes due to debility or dehydration where there will be reduction in vitreous volume.
Hydrophthalmos
Hydrophthalmos is an enlargement of the eyeball associated with increase in the quantity of aqueous humour. When hydrophthalmos is congenital it is called megaophthalmos or megaophthalmos congenitus.
Hydrophthalmos is usually the result of interference with the drainage of aqueous humour and may be due to the adhesion of iris to the cornea at the filtration angle.
The tunics of the eyeball, espically the sclera and cornea become thin and weak. This condition is common in cats.
Symptoms of Hydrophthalmos
Due to the general increase in the fluid contents the eyeball bulges forward causing exophthalmos and lagophthalmos. This causes drying or dessication and interference with the nourishment of the cornea.
The cornea becomes opaque, due to pannus. The lens is detached and usually floats in the aqueous humour and may become adherent to the cornea or vitreous humour.
Keratoglobus (protrusion of cornea into a globular enlargement) or keratoconus (conical enlargement of the cornea) may be observed.
Treatment of Hydrophthalmos
Anterior chamber centesis is performed to decompress the anterior chamber
If hydrophthalmos is due to adhesion of the iris to the cornea or other structural deformities, treatment is confined to removal of diseased eyeball.
Surgical technique
Method Enucleation of eye
The conjunctiva is held by forceps and is divided around the eyeball exposing the scleral insertions of the muscles of eyeball. These are divided one by one so that it will be possible to turn the eyeball and severe the rest of the attachments.
The eyeball is removed and the orbit is packed with sterile gauze to arrest haemorrhage. If tarsorrhaphy is to be performed, the edges of the lid are trimmed and sutured.
Method Extirpation of eye (Eviseration of orbit)
The palpebral borders of the eyelids are temporarily sutured together. An eplliptical cutaneous incision enclosing this suture line is made without opening into the conjunctival sac.
Retracting the skin edges, the eyeball along with its muscles is detached from the bony orbit by blunt dissection between the tenon’s capsule and bony orbit.
After division of the attachments close to the base of the orbit and removal of the eyeball the orbital cavity is packed with sterile gauze to control bleeding.
The skin edges are united by apposition sutures leaving a small gap at the inner canthus for removal of the gauze packing for subsequent dressings .
Strabismus or squint
Strabismus or squint is a condition where there is abnormal deviation in the position of the eyeball.
Different types of squint are–
- Horizontal squint when the deviation is along a horizontal plane. Horizontal squint may again be classified as lateral (divergent) squint and medial (convergent) squint.
- Vertical squint when the deviation is in the vertical plane. Vertical squint may be in the form of an upward deviation of the eyeball or a downward deviation of eyeball.
- Oblique squint when the deviation is in a direction other than the horizontal or vertical plane.

Ventral deviation and Vertical strabismus (squint) in a cow
Etiology
Squint may be a congenital condition without any apparent cause. Middle ear infections, brain tumours, etc. are sometimes responsible for squint.
Treatment
If squint is not due to any apparent disease condition like meningitis, surgical treatment may be adopted.
The object of the operation is to correct the position of the eyeball by cutting the particular eye muscle which is causing undue tension on the eyeball.
Surgical technique
With proper aseptic precaution, the eyelids are kept well retracted with wire speculum.
The conjunctiva in level with the muscle to be divided is held with a conjunctival forceps and is incised.
Through this incision a strabismus hook is introduced to locate the muscle to be divided.
The muscle is then cut close to its scleral attachment with a narrow, thin bladed knife introduced through the conjunctival wound.
The eyeball may rotate to the normal position as soon as the muscle is cut.
The eye speculum is released. Post operatively a suitable antibiotic topical drops is applied to the eye daily.
Glaucoma
Glaucoma is a disease condition of the eye characterized by marked rise in the intraocular pressure.

Glaucoma in left eye of a dog
Glaucoma is sometimes seen in dogs, it is very rare in other animals.
There is increased intraocular pressure due to excessive quantity of aqueous humour. It may result from increased production or decreased drainage of aqueous humour.
Symptoms
- Severe pain
- Peripheral Vision is greatly reduced
- The pupil is dilated
- Increased tension in the eyeball
- megalocornea and corneal edema
- The cornea is sensitive to touch
- Lacrimation
Examination with an ophthalmoscope reveals the optic disc appears to be concave (“cupping of the optic disc”).

Tonometry with tonopenvet device in a dog
The retinal arteries appear constricted because of the pressure, and retinal veins are engorged with blood due to the compression at the optic disc.
Pressure atrophy of the choroid and retina is evident by greyish patches.

Megalocornea (Nonprogressive, usually symmetric, bilateral enlargement of the diameter of the cornea) in left eye of a dog
Treatment
Palliative treatment consists of instilling pilocarpine (1/2%), diurectics, laxatives, salt-free diet, restricted water intake, etc.
Surgical treatment is not of much effective value but may provide temporary relief. The following operations may be tried.
Scleral puncture
Site of Scleral puncture– on the sclera, immediately behind the limbus and in front of iris, near the temporal canthus of the eye.
Before operation, sterilize the conjunctival cul- de-sac by instilling antibiotic eye drops and flush with sterile balanced salt solution. Proparacaine is used as a topical anesthetic.
The puncture is made through the bulbar conjunctiva and sclera to let out the aqueous humour.
Iridectomy
Eye is prepared by frequent instillation of antibiotic eye drops about twenty four hours prior to the operation and is flushed with balanced salt solution immediately before the operation.
Proparacaine solution is used as a surface anesthetic. Eye is kept open with speculum. Using a keratome the cornea is incised close to the limbus and in front of the iris, taking care not to injure the iris. When the knife is withdrawn, portion of aqueous humour escapes through this incision.
A portion of iris also protrudes and this is held with iris forceps or iris hook and is drawn out of the wound as much as required. Then it is swabbed with 1 in 2,000 adrenaline.
After a few seconds the protruding portion of iris is incised with a fine iris scissors. An iris probe is then introduced to push the remaining portion of iris back into position. Eye is again washed with balanced salt solution.
Another method of doing iridectomy is by performing keratectomy, using a corneal trephine. A portion of cornea 1⁄2 cm in diameter is cut and iridectomy is conducted as in the previous case. This opening is covered with a conjunctival keratoplasty.
Dermoid Cyst
Dermoid is a misplaced embryonic cutaneous tissue contains hair which causes irrtation to the cornea and conjunctiva. Corneal dermoids are usually seen in the lateral canthus extending on to the cornea.

Superficial keratectomy is the surgical treatment for Dermoid cyst.