Pathology of iop

Not every IP increase results in glaucoma.

Glaucoma is such increase of IP, which is accompanied by dis­turbance of visual functions and change of the optic disc (OD).

The cardinal signs of glaucoma are increase of IOP, constric­tion of visual field from the nasal side and the atrophy of the optic nerve with glaucomatous excavation.

Glaucoma can be: congenital; acquired (primary and secondary).

Congenital Glaucoma or Hydrophthalmos

There are distinguished three clinical forms of congenital glau­coma:

1. The classical or simple form — develops as a result of an in­complete resorbtion of the mesodermal tissue in the angle of the anterior chamber.

2. Congenital glaucoma with anomaly of the anterior part of the eye (aniridia, coloboma of the iris). It is caused by the abnor­mal development of the angle of anterior chamber.

3. Congenital glaucoma with neurofibromatosis and angioma­tosis of the head (encephalotrigeminal angiomatosis, Sturge — Weber — Dimitry's syndrome).

Sclera, cornea, limbus of the child's eye are very elastic, they stretch, the eye enlarges in the size and at the final stages reaches a considerably large size. Such condition is known as buphthalmos (a "bovine" eye). In 75% hydrophthalmos is bilateral. The disease is easy diagnosed within first days after birth in 90% of affected children.

Diagnosis methods of congenital glaucoma:

• lateral illumination, biomicroscopy (limbus, cornea, their size, transparency);

• keratometry;

• tonometry (under general anaesthesia or during deep physio-'ogical sleep);

• US-biometry (length of eye axis, depth of anterior chamber);

• ophthalmoscopy.

Clinical course. The following signs are typical for hydrophthalmos:

• stretched limbus (up to 2-3 mm, normal — 1 mm);

• large cornea (the norm — before 1 year — 9 mm, at 1 year — 10 mm);

• deep anterior chamber (the norm — 1.5-2 mm in newborns, 3-3.5 mm — in adults);

• enlargment of the eye size;

• increase of IOP;

• lowered vision;

• glaucomatous atrophy of the optic nerve (displacement of the vascular bundle, glaucomatous excavation, pale optic nerve).

Then the eye stretches and ruptures of discemetic membrane appear, thus permitting fluid to enter the corneal stroma with sub­sequent loss of transparency, lacrimation, photophobia, blepharos­pasm, redness. In later stages of glaucoma the leucoma of the cor­nea forms, it may be dystrophy of the cornea up to trophical ul­cer.

Hydrophthalmos has 4 stages.

1. The initial stage.

Diameter of the cornea is 12-12.5 mm, length of eye axis is in­creased by 1.5-2 mm. Fundus of the eye is normal.

2. The developed stage.

Diameter of the cornea is 13-14 mm, the length of axis of the eye is increased by 3-4 mm. There are glaucomatous excavation of the optic nerve, partial atrophy of the optic nerve in the fundus of the eye.

3. The late stage.

Diameter of the cornea is more than 14 mm. Axis of the eye is more than 24 mm. There are atrophy of the optic nerve and glau­comatous cup in the fundus of the eye.

4. The terminal stage.

Absolute blindness, staphilomas of the sclera and the cornea, the corneal leucoma, complete atrophy of the optic nerve with glau­comatous cup (excavation).

Treatment is only surgical: goniotomy and goniopunctura, la­ser surgery, sinusotrabeculotomy, reconstructive microsurgery of the angle of the anterior chamber.

An operation should be performed early, as soon as the diag­nosis has been established.