Synechia
Encyclopedia
A synechia is an eye
condition where the iris
adheres to either the cornea
(i.e. anterior synechia) or lens (i.e. posterior synechia). Synechiae can be caused by ocular trauma
, iritis
or iridocyclitis
and may lead to certain types of glaucoma
. It is sometimes visible on careful examination but usually more easily through an ophthalmoscope or slit-lamp.
Anterior synechia causes closed angle glaucoma, which means that the iris closes the drainage way of aqueous humour which in turn raises the intraocular pressure. Posterior synechia causes glaucoma too but with a different mechanism, that due to adherence between iris and the lens block the way of aqueous from posterior chamber to the anterior chamber which in turn raises the intraocular pressure.
, are useful in breaking and preventing the formation of posterior synechia by keeping the iris dilated and away from the crystalline lens. Dilation of the pupil
in an eye with synechia can cause the pupil to take an irregular (non-circular) shape as shown in the photograph. If the pupil can be fully dilated during the treatment of iritis, the prognosis for recovery from synechia is good. This is a treatable status.
To subdue the inflammation, use topical corticosteroid
s. If the intra-ocular pressure is elevated then use a Beta Blocker
such as timolol
.
Human eye
The human eye is an organ which reacts to light for several purposes. As a conscious sense organ, the eye allows vision. Rod and cone cells in the retina allow conscious light perception and vision including color differentiation and the perception of depth...
condition where the iris
Iris (anatomy)
The iris is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupils and thus the amount of light reaching the retina. "Eye color" is the color of the iris, which can be green, blue, or brown. In some cases it can be hazel , grey, violet, or even pink...
adheres to either the cornea
Cornea
The cornea is the transparent front part of the eye that covers the iris, pupil, and anterior chamber. Together with the lens, the cornea refracts light, with the cornea accounting for approximately two-thirds of the eye's total optical power. In humans, the refractive power of the cornea is...
(i.e. anterior synechia) or lens (i.e. posterior synechia). Synechiae can be caused by ocular trauma
Physical trauma
Trauma refers to "a body wound or shock produced by sudden physical injury, as from violence or accident." It can also be described as "a physical wound or injury, such as a fracture or blow." Major trauma can result in secondary complications such as circulatory shock, respiratory failure and death...
, iritis
Iritis
Iritis is a form of anterior uveitis and refers to the inflammation of the iris of the eye.-Types:There are two main types of iritis: acute and chronic. They differ in numerous ways....
or iridocyclitis
Iridocyclitis
Iridocyclitis, a type of anterior uveitis, is a condition in which the uvea of the eye is inflamed.Iridocyclitis isInflammation of the iris and the ciliary body.- Symptoms :Symptoms include:* Photophobia* Redness* Watering of the eyes* Lacrimation...
and may lead to certain types of glaucoma
Glaucoma
Glaucoma is an eye disorder in which the optic nerve suffers damage, permanently damaging vision in the affected eye and progressing to complete blindness if untreated. It is often, but not always, associated with increased pressure of the fluid in the eye...
. It is sometimes visible on careful examination but usually more easily through an ophthalmoscope or slit-lamp.
Anterior synechia causes closed angle glaucoma, which means that the iris closes the drainage way of aqueous humour which in turn raises the intraocular pressure. Posterior synechia causes glaucoma too but with a different mechanism, that due to adherence between iris and the lens block the way of aqueous from posterior chamber to the anterior chamber which in turn raises the intraocular pressure.
Management
Mydriatic/cycloplegic agents, such as topical atropineAtropine
Atropine is a naturally occurring tropane alkaloid extracted from deadly nightshade , Jimson weed , mandrake and other plants of the family Solanaceae. It is a secondary metabolite of these plants and serves as a drug with a wide variety of effects...
, are useful in breaking and preventing the formation of posterior synechia by keeping the iris dilated and away from the crystalline lens. Dilation of the pupil
Pupil
The pupil is a hole located in the center of the iris of the eye that allows light to enter the retina. It appears black because most of the light entering the pupil is absorbed by the tissues inside the eye. In humans the pupil is round, but other species, such as some cats, have slit pupils. In...
in an eye with synechia can cause the pupil to take an irregular (non-circular) shape as shown in the photograph. If the pupil can be fully dilated during the treatment of iritis, the prognosis for recovery from synechia is good. This is a treatable status.
To subdue the inflammation, use topical corticosteroid
Corticosteroid
Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex. Corticosteroids are involved in a wide range of physiologic systems such as stress response, immune response and regulation of inflammation, carbohydrate metabolism, protein catabolism, blood electrolyte...
s. If the intra-ocular pressure is elevated then use a Beta Blocker
Beta blocker
Beta blockers or beta-adrenergic blocking agents, beta-adrenergic antagonists, beta-adrenoreceptor antagonists or beta antagonists, are a class of drugs used for various indications. They are particularly for the management of cardiac arrhythmias, cardioprotection after myocardial infarction ,...
such as timolol
Timolol
Timolol maleate is a non-selective beta-adrenergic receptor blocker.-Uses:In its oral form , it is used:* to treat high blood pressure* to prevent heart attacks* to prevent migraine headaches...
.