Glaucoma

Glaucoma is the increase in intraocular pressure beyond normal limits.

Inside the eye there is a liquid called aqueous humor, the balance between production and drainage is essential to maintain correct intraocular pressure. The first occurs in the ciliary bodies while the second occurs at the level of the trabecular meshwork; the latter is positioned in the iridocorneal angle, which is the internal junction area between the base of the iris and the periphery of the cornea.

Intraocular pressure is distributed over the retina, in particular over the nerve fibers of which it is composed. These then flow into the back of the eye and form the optic nerve.

The retina and optic nerve play an essential role in vision, because when light enters the eye it generates an electrical impulse in the nerve fibers of the retina which, via the optic nerve, is transmitted to the brain where image formation occurs.

What are the symptoms of glaucoma?

The consequence of the increase in intraocular pressure is compression damage to the nerve fibers of the retina and the optic nerve. The increase in pressure can be rapid or slow over time: in the first case, the disease manifests itself in a striking way with:

• severe pain in the affected eye;
• nausea
• headache;
• vomit;
• visual blurring;
• red eye.

In the second case (the most widespread form), however, the disease is often asymptomatic and, if symptoms are present, they are so mild that they are often overlooked. The patient, therefore, realizes that something is wrong only when the disease is in an advanced stage. In particular, if the optic nerve is damaged, there is a reduction in its functional capacity to transmit the electrical impulse to the brain, resulting in an irreversible reduction in visual capacity which, in many cases, can lead to total loss of sight.

What are the consequences of glaucoma on vision?

It is necessary to distinguish visual ability into qualitative and quantitative: in the first case, the measurement takes place during the eye examination and consists of evaluating the ability or otherwise to read up to 10/10; in the second case, however, the measurement is performed with the examination of the visual field and consists of evaluating the quantity of the external world that the eye is able to perceive (visual amplitude) and, generally, is requested after the eye examination .

What are the results? If you lose the ability to see 10/10 the perception of discomfort is immediate; if, however, only the reduction of visual width occurs, the perception is very blurred and it is possible to notice it only when this is very advanced (e.g. while driving you notice at the last moment a pedestrian crossing the road).

In glaucoma the reduction of vision manifests itself first in quantitative (peripheral) vision and then in qualitative (central) vision.

What are the practical consequences of glaucoma?

The consequences that a patient suffering from glaucoma can experience are different, also and above all on a practical level, therefore in the course of daily life. In particular, they can involve:

• loss of driving licence;
• loss of weapons licence;
• significant limitations in carrying out normal daily activities;
• significant negative repercussions on working capacity.

How many types of glaucoma are there?

There are different types of glaucoma, each with very different characteristics, symptoms and consequences. First, glaucoma can be distinguished into:

• primary glaucoma: when, due to anatomical or functional causes, the relationship between production and intraocular drainage is altered;
• secondary glaucoma: arises from secondary factors.

Furthermore, two large macro categories of glaucoma can be distinguished:

Glaucoma at birth/childhood:

• congenital;
• malformative;
• neoplastic;
• neovascular;
• inflammatory;
• post traumatic;
• post surgery;
• malignant.

Adult glaucoma:

• open-angle pigmented;
• open-angled unpigmented;
• closed corner;
• refractive defects (myopia, hyperopia);
• malformative;
• neoplastic;
• inflammatory;
• post traumatic;
• post surgery;
• drugs;
• neovascular;pseudo exfoliative;
• phacolytic;
• low pressure (still the subject of discussion and sharing);
• malignant.

What are the main risk factors for glaucoma?

OIn addition to the increase in intraocular pressure, identified (at least to date) as the only known cause of glaucoma, it is possible to detect further risk factors:

• familiarity;
• race;
• age;
• metabolic diseases;
• low systemic pressure;
• corneal thickness reduced compared to average.

How is glaucoma diagnosed?

In most cases, given that glaucoma is almost always an asymptomatic disease, the diagnosis is obtained during a routine eye examination. If the ophthalmologist notices some warning signs, he may decide to carry out further in-depth tests:

• three-mirror Goldmann lens: it is used during the eye examination to see the anatomy of the corneal iris angle and the appearance of the trabecular meshwork;
• ophthalmoscopy: allows you to see the retina and the optic nerve (the visible part of the optic nerve is called the head or papilla);
• Pentacam: allows you to evaluate the opening of the iris corneal angle in degrees;
• tonometry: is a diagnostic technique used to check the internal pressure of the eye; it is always related to pachymetry;
• optical coherence tomography (OCT): it is a test that returns high resolution images of layered (tomographic) scans of the central part of the retina (macula), of the cornea. For glaucoma it is important because with the SLT and ONH modules it is possible to measure the thickness of the retinal ganglion fibers and the optic nerve head;
• corneal pachymetry: it is a test that allows you to measure the thickness of the cornea; it is always related to tonometry;
• study of the visual field: it is a fundamental test for the diagnosis and control of glaucoma therapy as it allows to evaluate the quantitative visual capacity and its possible reductions in the peripheral perception of the image;
• ultrabiomicroscopy (UBM): it is an ultrasound performed with high frequency probes. It is used to visualize the anatomical relationships between the iris, corneal iris angle, lens and ciliary bodies;
• FORUM program: allows the archiving, sharing and overlaying of images acquired via OCT and field of view. Therefore, it is able to immediately provide more information than a single exam and to evaluate any changes over time.

What are the treatments for glaucoma?

The aim of all therapies for the treatment of glaucoma is to lower the intraocular pressure value until it is within the limits of normality for the eye in question. To achieve the goal, medical, parasurgical and/or surgical therapies can be used.

• Medical therapies:

use of eye drops containing drugs capable of lowering intraocular pressure either by reducing the production or increasing the outflow of aqueous humor;
tablets containing drugs capable of lowering intraocular pressure by reducing the production of aqueous humor.

• Laser parasurgery (outpatient):

yag laser iridotomy: it is used in closed-angle glaucoma and creates a small hole in the periphery of the iris; the aim is to improve the internal hydrodynamics of the eye;
trabeculoplasty (ALT): it is used in the treatment of open-angle glaucoma to improve outflow;
Selective trabeculoplasty (SLT): is used in the treatment of open-angle glaucoma to improve outflow.

• Laser parasurgical (operating room):

micropulsed laser: reduces the production of aqueous humor.

• Surgical therapies (operating room):

non-filtering surgery: increases the outflow capacity of the trabecular meshwork;
filtering surgery: it does not influence the production or outflow capacity but creates a passage between the inside of the eye and the subconjunctival space;
intravitreal injection of anti-VEGF drugs.

Can glaucoma be prevented?

Glaucoma is a treacherous and insidious pathology because in most cases it is completely asymptomatic and can only be highlighted when it is in a stage that is as advanced as it is irreversible. Some forms of glaucoma are preventable, others are not. An early diagnosis is essential to limit or avoid visual damage due to glaucoma.

Therefore the watchword in the diagnosis of glaucoma is prevention.

MediClinic presents itself as a highly specialized center for the diagnosis, study and treatment of glaucoma. The presence of competent medical personnel and cutting-edge equipment allows for an early and accurate diagnosis of glaucoma.

All the previously listed diagnostics (excluding UBM) are available in MediClinic and, once the diagnosis is obtained, it is essential to carry out the correct therapy.

All the therapies previously listed are performed in MediClinic (excluding intravitreal injection of anti-VEGF). Furthermore, the equipment present in MediClinic allows you to monitor glaucoma over time, allowing you to intervene promptly if necessary.