About CataractA cataract is a clouding of the eye’s natural lens, that blocks the light to reach the retina, causing visual deterioration and finally vision loss. The eye’s natural lens is located behind the iris and is normally clear. A cataract cannot be prevented, nor can be treated with medication. It must be treated by surgical removal. Cataract is a very common condition and usually occurs with age. Sometimes it can be caused by trauma, certain diseases (eg diabetes eye.) or drugs such as the chronic use of cortisone.
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The main symptom of cataract:The main symptom of cataract is the clouding of sight which cannot be corrected by using glasses. Other symptoms are double vision, glare and reflections around light sources that impair sight. The hardening of the lens nucleus during cataract development, causes refractive myopia, that is an increase in myopia to nearsighted people but also a decrease in hyperopia to farsighted people. Cataract symptoms do not always manifest at the same time in both eyes. One eye may have worse sight and needs to be treated first.
Cataract surgery is an outpatient surgery. It is performed by applying local anaesthesia and lasts a few minutes. During cataract surgery the cloudy lens is removed and replaced by the proper artificial lens (intra-ocular lens implant) that restors sight. Simultaneous correction of astigmatism and presbyopia are possible using premium intra-ocular lenses (IOLs). Eye sight is usually fully restored during the first three to seven days after surgery depending on the stage and severity of cataract. After the surgery, the patient can immediately return at home and everyday life. Mature or hypermature cataracts are more susceptible to complications during surgery. In any case, doctor’s experience and technique plays a major role in order to have the desired result
What is glaucoma?The term “glaucoma” is used for a group of diseases whose common characteristic is damage of the optic nerve and visual loss. It is a leading cause of blindness for people over 60 years old. Glaucoma is associated with increased pressure in the eye. Glaucoma is a potentially blinding condition where the increased pressure inside the eye damages the optic nerve. The optic nerve is the “cable” that carries visual stimulants from the eye to the brain. The optic nerve is composed of a large number of nerve fibers. Each fiber of the optic nerve is responsible for conveying visual stimuli from a specific point of our visual field, and the damage to a bundle of these fibers leads to a reduction or loss of vision in the corresponding segment. The nerve fibers that were unfortunately destroyed can not be regenerated and the part of our visual field in which vision was reduced or lost does not return. The main problem with the most common form of glaucoma called “chronic simple glaucoma” is the absence of symptoms. The eye does not hurt nor is it easy to “perceive” the reduction of the visual field without the use of specific medical tests. Modern high-tech diagnostic tools are used today for the diagnosis of the early stages glaucoma patients. Early diagnosis of this very common disease can stop the progression and in conjunction with the latest medications, prevent the blindness. However, reality is different. The is a lack of awareness amongst patients so as to promptly visit an ophthalmologist for an examination, resulting in too many glaucoma cases remaining undiagnosed and millions of people around the world to losing their sight without reason.
There are two major types of glaucoma.
Primary open-angle glaucoma
This is the most common type of glaucoma.
Open-angle glaucoma develops slowly over time, there is no pain and causes no vision changes, at first. Peripheral vision is affected first, but eventually the entire vision will be lost resulting in blindness, if not treated.
But blindness from glaucoma can often be prevented with early treatment.
Regular eye exams is the only way to find early signs of damage to their optic nerve.
Angle-closure glaucoma (also called “closed-angle glaucoma” or “narrow-angle glaucoma”) In close/narrow-angle, the drainage angle is completely closed because of forward displacement of the iris against the cornea, resulting in the inability of the aqueous fluid to flow from the posterior to the anterior chamber and then out of the trabecular network. This accumulation of aqueous humor causes an acute increase in pressure and pain.
Angle-closure glaucoma is a true eye emergency, can cause blindness if not treated right away.
The most common symptoms of an acute angle-closure glaucoma attack: Severe eye pain, headache, nausea, vomiting, blurred vision, rainbow-colored rings or halos around lights.
Screening for glaucoma is usually performed as part of a standard eye examination.
Testing for glaucoma should include:
measurements of the intraocular pressure via tonometry, anterior chamber angle examination or gonioscopy, and examination of the optic nerve to look for any visible damage. A formal visual field test should be performed. The optic nerve and the retinal nerve fiber layer can be assessed with imaging techniques such as optical coherence tomography. Visual field loss is the most specific sign of the condition; however, it occurs later in the condition.
The modern goals of glaucoma management are to avoid nerve damage, and preserve visual field and total quality of life for patients, with minimal side-effects. This requires appropriate diagnostic techniques and follow-up examinations, and judicious selection of treatments for the individual patient. Although intraocular pressure (IOP) is only one of the major risk factors for glaucoma, lowering it via various pharmaceuticals and/or surgical techniques is currently the mainstay of glaucoma treatment. A review of people with primary open-angle glaucoma and ocular hypertension concluded that l IOP-lowering treatment slowed down the progression of visual field loss.
The goal of currently available glaucoma therapy is to preserve visual function by lowering intraocular pressure (IOP) below a level that is likely to produce further damage to the nerve.
Intraocular pressure can be lowered with medication, usually eye drops, laser treatment, or surgery. If treated early, it is possible to slow or stop the progression of disease.
Poor compliance with medications and follow-up visits is a major reason for vision loss in glaucoma patients. Patient education and communication must be ongoing to sustain successful treatment plans for this lifelong disease with no early symptoms.
Laser treatments may be effective in both open-angle and closed-angle glaucoma. A number of types of glaucoma surgeries may be used in people who do not respond sufficiently to other measures ( eye drops or laser ).
Treatment of closed-angle glaucoma is a medical emergency.
Glaucoma surgery, facilitates the escape of excess aqueous humor from the eye, decreases intraocular pressure and prevents vision loss.
Conventional surgery to treat glaucoma makes an opening in the trabecular meshwork, which helps fluid to leave the eye and lowers intraocular pressure.
In Myopia long-distance vision is blurred. This occurs either because the the cornea (anterior surface of the eye) has too much curvature, or because the eye is large in size, or both. The image is formed in front of the retina of the eye.
In hyperopia, long and short-distance vision is blurred. The eye is usually smaller. The image is formed behind the retina of the eye.
In the case of astigmatism, the curvature of the cornea is irregular resulting in distorted image to be formed in front or behind the retina depending on the type of astigmatism (myopic or hyperopic).
Presbyopia is the condition, in which the eye loses its ability to focus on near objects due to aging. It’s a normal aging process and it starts around 40 years of age.
Keratoconus is a cone-shaped, non-inflammatory distortion of the central area of the cornea. It is a disease of unknown cause, although there is evidence for a genetic predisposition. It usually occurs during adolescence and slowly progresses until the age of 25 years. The disease affects both eyes, but the development time may be different for each.
The diagnosis is made clinically and confirmed by imaging methods such as corneal topography.
Keratoconus advances at varying rates and differently in each eye. Progression is generally more rapid, the earlier the age of onset. Keratoconus causes increasing blurriness and shortsightedness in vision, light sensitivity and halos and ghosting around light sources.
Progression usually occurs to an age of around 40-45 years and then tends to stabilize. On average, the most significant progression occurs in the first 15-20 years after the time of onset.
Stages of Keratoconus
Early keratoconus (Forme Fruste) has only very slight corneal distortion; it has little or no effect on the quality of vision and exhibits minimal or no progression. Spectacles are usually successful in correcting the myopia and astigmatism and give adequate vision. Soft contact lenses, spherical or with a toric correction, can be a good option for general use or just for sporting activities.
Corneal distortion increases and corneal changes typical of keratoconus can be observed. As the vision quality with spectacles decreases, rigid gas permeable contact lenses become the option for better quality vision.
The rigid gas permeable contact lens covers the corneal irregularity with a regular hard surface and neutralises 90% of the corneal distortion resulting in much clearer vision.
Substantial corneal distortion, difficulty in Contact lens fitting and tolerance. Scleral rigid gas permeable contact lenses may be useful to maintain an appropriate fitting and improve stability and comfort
Dramatic corneal distortion, substantial corneal scarring and thinning. Often there is poor vision with rigid gas permeable contact lenses, substantially reduced contact lens tolerance and usually very difficult to fit an acceptable rigid gas permeable contact lens.
Corneal transplant surgery, while still the most successful of all transplant surgeries, remains an invasive surgical procedure that has a long healing process and presents many postoperative challenges. It is also associated with a number of potential complications, including the possibility of graft failure. Younger patients with progressive keratoconus are more likely to reach a stage requiring a corneal transplant, typically in a more rapid fashion.
Corneal collagen crosslinking ( CXL), a procedure designed to harden the cornea and halt progression, is widely offered to patients today to prevent progression to the advanced and severe stages of keratoconus. It is hoped that in the future, crosslinking will significantly reduce rates of corneal transplantation and the difficulty of fitting contact lenses to keratoconus patients.
Corneal collagen cross-linking should be a first-line treatment for young patients with progressive keratoconus with the goal of reducing preventable vision loss and the need for corneal transplants.
It is important to understand that CXL alone does not correct the patient’s vision. Although the procedure is commonly associated with some flattening of the corneal curvature as well as post-crosslinking changes in refraction, patients will generally still need contact lenses to correct their vision.
Macular degenerationMacular degeneration (also called age-related macular degeneration or AMD) refers to a group of degenerative diseases of the retina – in particular the macula, which is responsible for central and fine-detail vision.Tthis is a painless condition and peripheral vision is not affected, many people are not aware that they have AMD until the disease is in the advanced stages. Once advanced, AMD can be classified into wet and dry forms. Most people have the dry form of AMD. People aged over 50 years or those with a family history of macular degeneration face the greatest risk. This eye disease causes people to lose the ability to distinguish faces, read, drive and see fine detail. Early detection and treatment offers the best hope of minimising significant damage. If you have difficulty reading, distinguishing faces, or start to see dark or empty patches in your central vision, have your eyes checked immediately Diagnosing macular degeneration 1. Regular eye examinations 2. Home screening An Amsler Grid may be recommended for people at high risk of developing macular degeneration, this grid contains a series of horizontal and vertical lines with a dot in the middle. If the lines appear wavy or any are missing, have your eyes checked immediately. 3. Fluorescein angiography 4. Optical coherence tomography (OCT)
Retinal vein occlusion occurs when the veins in the retina are blocked and the build-up of pressure causes smaller downstream blood vessels to leak. The blockage can occur in a branch vein with vision loss restricted to part of the visual field (branch vein retinal occlusion) or a central vein with the entire visual field affected (central vein retinal occlusion).
Retinal detachment is a serious condition in which the retina lining the back of the eye separates from the wall of the eye. If not treated, it can lead to permanent blindness. Surgery under local anaesthesia is needed to reattach the retina.
Retinal tears are not usually as serious as a retinal detachment, but they can develop into a retinal detachment if untreated. Retinal laser treatment (also known as retinal laser
surgery or retinal tear surgery) is an effective treatment for retinal tears.
Retinitis pigmentosa is the name for a range of genetic diseases that damage the retinal rod and/or cone cells (photoreceptors), causing vision loss. Unfortunately, there is no known treatment. An ophthalmologist can give you advice on what to expect and how to manage the disease.
Epiretinal membrane, also known as macular pucker, epiretinal membrane occurs when a thin sheet of scar-like tissue grows on the surface of the macula and interferes with central vision. Your doctor will monitor progression using an OCT scan and fluorescein angiogram. Vitrectomy may be recommended.
Eye floaters are specks or smudges that float around your field of vision, caused by the degeneration of the clear, jelly-like fluid that fills your eye (the vitreous). Most floaters are harmless, but they may also be a sign of more serious retinal conditions. New floaters should always be checked by an eye specialist. Laser treatment or vitrectomy surgery can be performed for severe floaters if they are affecting your quality of life.
Diagnosing retinal conditions
- Retinal examination (dilated ophthalmoscopy)
- Digital retinal photography
State-of-the-art equipment is used to produce high-resolution photographs of your retina, optic nerve and blood vessel
- Fluorescein angiography
A fluorescein angiogram uses a fluorescent dye (injected into a vein in the arm) to show any blockages or leaks in the blood vessels supplying the retina. or leaks and will use a special camera to take photographs. Your vision will be blurred for up to 12 hours after the test.
4.Optical coherence tomography (OCT) the retina and the optic nerve
OCT is a non-invasive test that captures images of the retina and the optic nerve. The OCT scans the eyes without making direct contact. The procedure takes less than 10 minutes.
These injections are also called intravitreal injections. They are administered in the clinic or day surgery. The eye is numbed with a local anaesthetic to stop any pain. Ongoing treatment is often necessary for many retinal disorders. (e.g Retinal vein occlusion)