Eye diseases and conditions that require surgical treatment – keratoplasty
The cornea is one of the major optical structures of the eye. It is very sensitive, which is due to its almost continuous contact when interacting with the environment. The cornea is in the area of the eye fissure, that is why it is exposed to light, heat, microorganisms, foreign bodies. It may have a variety of anatomical and functional disorders (tumors, dystrophic and inflammatory processes, traumas).
Today Dnipropetrovsk Regional Clinical Ophthalmological Hospital has the most modern diagnostic capabilities of diagnostics, advanced techniques and unique equipment for conducting various studies which allow to identify defects at the earliest stages. In order to protect yourself from possible problems, and make sure that vision is not in danger, you need to have diagnostic examination at least once a year.
Diseases, which can lead to the need in keratoplasty:
I. Corneal abnormalities:
1. Megalocornea (macrocornea);
6. Congenital opacities.
ІІ. Corneal dystrophies:
ІІ.І Congenital (primary) corneal dystrophies
1. Congenital stroma corneal dystrophy;
2. Congenital endothelial corneal dystrophy, type I;
3. Congenital endothelial corneal dystrophy, type II.
ІІ.ІІ Acquired (secondary) corneal dystrophy
1. Endothelial corneal dystrophy;
2. Endothelial-epithelial corneal dystrophy;
3. Bullous keratopathy.
ІІІ. Corneal degeneration:
1. Stromal thinning of the cornea.
ІV. Injuries and damage:
- Eroding eye injuries;
- Traumatic corneal defects;
- Fresh serious and very serious corneal burns;
- Persistent walleyes and corneal scars formed after traumas, burns, operations that led to appearance of white or swollen areas on the cornea.
V. Inflammation of the cornea (keratitis):
a) Bacterial coccal keratitis
- Corneal ulcer serpens;;
b) Tuberculous keratitis
- Deep diffuse, deep limited, and sclerogenic.
c) Syphilitic (parenchymal) keratitis
d) Malarial, brucellous keratitis..
2. Viral keratitis
- Herpetic keratitis (punctate, vesicular, dendritic, metagerpetic, disciform and deep diffuse uveokeratitis).
3. Infectious - allergic keratitis
- Tuberculous-allergic keratitis (phlyctenular, scrofulous, deep infiltrative keratitis (sided infiltrate, sided ulcer), fascicular keratitis, keratitis pannosa, necrotic keratitis).
4. Allergic keratitis.
5. Metabolic keratitis:
- Epіthelial xerosis;
6. Other types of keratitis:
a) Neuroparalytic keratitis;
b) Mycotic keratitis.
7. Keratitis results:
- Epіthelial cysts of the anterior eye chamber;
- Inflammatory tissue, which does not react on treatment by antibiotics or anti-viral medications.
- Fіstulas and cornea perforation;
- Deep corneal lysis;
- Intracorneal abscess;
- Slight cloudiness;
- Corneal spot;
VІ. Corneal tumors, peripheral rim, sclerae.
Megalocornea (macrocornea) – a disease at which corneal sizes increase more than by 1 mm. comparing with age norm.
Mіcrocornea – a state at which is decreased comparing to age norm more than by 1 mm.
Megalocornea (macrocornea) and microcornea refer to corneal abnormalities that are rebellious, and which affect the clinical refraction and visual functions as cornea size changes include changes of its curvature. It is necessary to know that both micro- and macrocorneas can be followed by ocular hypertension, i.e. lead to the development of congenital glaucoma.
Embryotoxon – is a ring-shaped peripheral corneal opacity, which look like “circular arc”.
Keratoconus (from Greek. Κέρας – “horn” and κῶνος – “cone”) – is non-inflammatory degenerative disease of the cornea, leading to its gradual thinning, weakening and pushing out under the influence of intraocular tension. The cornea is in a cone-like form. Because of this, a person has rapidly progressing astigmatism, myopia, and finally appears corneal opacity, which leads to a significant vision deterioration of the patient and disability. The disease is the most common form of corneal dystrophy.
Increasing of frequency of occurrence of the disease in recent years has been seen by many ophthalmologists and it is due to both improved early diagnosis (appearance of the optical corneal measurer) and with a true increase in frequency of the disease.
According to the data from different authors the prevalence of keratoconus figures up to:
from 1 to 400 per 100,000 people. According to the data of the National Keratoconus Fund of the United States the frequency of keratoconus is 1 for 2,000 people in the general population. The average number of repeated patients was 2 cases per 100,000 people a year. The frequency does not depend on geographical, social or cultural characteristics of the population. In 10% of patients keratoconus is found among close relatives, but mainly it is a sporadic disease. Modern complex methods of treatment of keratoconus allow to slow down, stop and, if possible, to correct refractive defects in some cases without keratoplasty surgery.
More recently, the treatment of keratoconus was limited by patient’s wearing hard contact lenses as long as the progression of the disease did not cause thinning of the cornea, its localized opacity, visual acuity deterioration, resistant intolerance to contact correction and inability to obtain adequate visual acuity using spectacle correction. In such cases, the need for penetrating keratoplasty was considered the only possible and correct tactics of surgical treatment of keratoconus.
The concept of modern treatment of keratoconus is based on three basic conditions:
- To stabilize the anatomy of the cornea;
- To slow down the progression of the disease;
- To achieve maximum visual acuity.
Effective medical care for patients with keratoconus at different stages of pathological process can be realized through the following operational methods:
• Cross-linking of the corneal collagen;
• Intrastromal segments implantation;
• Penetrating keratoplasty using a corneal graft.
Keratoglobus – is a congenital defect of the eye development, in which the entire cornea pushes out, despite the fact that it has the correct curvature shape (unlike keratoconus). The cornea is thinned over the entire surface approximately by 1/3 of its thickness. In case of ophthalmometry appears altered, compared with the norm, radius of curvature of the cornea with symptoms of astigmatism. Vision is reduced and therefore ametropia shown with the help of glasses or contact lenses. In cases where the optical correction is not possible, for example, in case of expressed keratoglobus, is conducted keratoplasty surgery.
Congenital opacities due to violation of embryonic development because of mother’s illness.
- Congenital (primary) corneal dystrophies caused by metabolic disorders mainly protein metabolism, they require regular monitoring at ophthalmologist;
- Acquired (secondary) developed corneal dystrophies due to local processes in the eye (injuries, burns, infectious lesions of the cornea, glaucoma) and at pathologies of the collagen tissue. Secondary dystrophies include swollen forms of dystrophy (bullous keratopathy, epithelial-endothelial corneal dystrophy), which develop in response to corneal endothelial damage.
Congenital (primary) dystrophies are hereditary, they often occur at children early age and have a progressive course and may be caused also by a violation of normal pregnancy.
Congenital dystrophy of the corneal stroma – is a hereditary disease, which is characterized by opacity of the corneal coat, the transparent in the norm. This is a very rare disease (at the time of 2009 is described only in four families), has autosomal-dominant transmission mechanism (i.e. which is not related to the sex chromosomes X and Y).
There is a congenital mutation of one of the genes that is responsible for the formation of one of the chemical components of the stroma of the cornea – proteoglycan called decorin.
The disease comes out slowly with a progressive decline of vision, usually in both eyes. In some cases, this can lead to the formation of strabismus – eyes converge or diverge mainly by means of one eye. Also, you may experience occasional pain in the eye and head with lacrimation from it. During examination, there is elevated intraocular tension, the doctor can make a diagnosis of "glaucoma". If the patient addresses to a doctor about vision deterioration, the expert sees signs of corneal dystrophy, which in this case look like flakes or feathers in the stroma of the cornea, and with the age these inclusions become more. Corneal coat loses its transparency, especially in its upper part. The cornea does not change its thickness, but it becomes more difficult to discern its endothelium, although it does not change its structure. to The cornea does not have erosion or other damages, and no newly formed vessels. If you look at the cornea under high magnification, it is seen that the components of its stroma – collagen fibrils are smaller in diameter, but they are much denser, which explains stromal opacities.
Congenital corneal stroma dystrophy is often complicated by the development of glaucoma, so it is important to monitor intraocular tension constantly.
Pivotal treatment of this disease is keratoplasty. Before that is requires a careful preparation of the patient with the measurement of the cornea.
Congenital endothelial corneal dystrophy, type I – is a hereditary disease that progresses slowly and is characterized by a change in the endothelial cells of the cornea, generalized by edema initially in the endothelium, and with the time by progression of the disease – swelling spreads to other parts of the cornea. The pathology does not have any systematic violations.
Congenital endothelial corneal dystrophy, type I is caused by mutations of a certain area in chromosome 20. The mutation is transmitted in the family by an autosomal-dominant type. The molecular defect that occurs in such a case is not thoroughly unknown.
There is also a hypothesis that the disease can be combined with the posterior polymorphous corneal dystrophy, type I.
It is also important to distinguish between the congenital endothelial dystrophy type I and the dystrophy type II, which is an autosomal-recessive disease, and also the syndrome Har-Bolyai, which is very similar to the disease, and even the mutation is located in the same chromosome, but is combined with sensorineural dull hearing.
The pathology occurs from the birth. It occurs with almost complete opacity of the cornea, sometimes with some asymmetry. First, child sees almost normally, but the disease tends to progress, so when the person becomes mature, he or she sees very badly. The patient is also concerned about photophobia and lacrimation. In case of congenital corneal endothelial dystrophy often develops glaucoma. This is caused by the formation of structures of the anterior eye chamber during the prenatal period.
During examination, the doctor sees the swelling of the cornea, through which it can thicken in 2-3 times. The patient sees things like in fog, and in advanced cases the vision so low that it looks as if he or she sees through frosted glass.
The ophthalmologist can observe such a picture on the posterior surface of the cornea which resembles orange peel. Also, at electron microscopy it is seen that the endothelium of the cornea is thinned, and in some areas it can be partially missing. But in the thickened layers of the Descemet’s membrane are seen changed and randomly placed collagen fibers. The rest of endothelial cells are often vacuolized and arranged in two layers, some of them contain granules of melanin.
In the case of such congenital eye pathologies is recommended eye surgery – penetrating keratoplasty. This will solve the problem of vision deterioration at any age.
Congenital endothelial corneal dystrophy type II – is a hereditary disease that occurs with a progressive change and opacity of the corneal tissue and the eye coat. This is a rare subtype of the posterior corneal dystrophy, characterized by diffuse opacity of the coat with its noticeable thickening.
Most of the cases were found among children of those parents who are blood relatives. Cases were registered in Burma, Saudi Arabia, India, Pakistan, Ireland.
There happens the SLC4A11 gene mutation, which probably responses to the synthesis of a specific transport protein that regulates intracellular concentration of this element of the periodic system as boron.
The disease is transmitted in an autosomal recessive way. This means that the patient inherits the same abnormal gene with the same characteristics from both parents, each of whom was a carrier of the gene but with no symptoms of the disease. The risk of transmission of disease with each pregnancy is 25%.
The disease occurs from birth. Its symptoms are similar to symptoms of congenital endothelial corneal dystrophy type I, but they are mostly more severe. A sick person sees like through the fog, from birth there is nystagmus (movements of the eyeballs while focusing on some object). Photophobia and lacrimation are minimal or absent. The course of the disease is relatively stable. Sometimes patients have sensorineural deafness. The cornea looks swollen because of significant edema of its stroma.
At the second type of congenital corneal endothelial dystrophy there is an increased susceptibility to altered endothelial synthesis, resulting in a homogeneous posterior Descemet’s membrane.
For vision correction is recommended penetrating keratoplasty or posterior lamellar keratoplasty.
Acquired (secondary) dystrophies may develop due to: collagen disorder, congenital glaucoma, progressive keratoconus, vitamin deficiency, burns of the conjunctiva and sclera, lack of tear fluid, and others.
Endothelial corneal dystrophy is the most common among the elderly because of its physiological loss of endothelial cells. Through a thick swollen cornea light rays cannot properly come inside the eyes to form an image on the retina, which leads to a strong vision deterioration. In severe cases, are formed bullae (vesicles on the front surface of the cornea). Bulla rupture causes discomfort and pain.
It is impossible to cure the disease by a conservative method. In case of corneal dystrophy the only way to restore sight and get rid of pain is keratoplasty surgery.
Endothelial-epithelial dystrophy is a secondary dystrophic disease of the cornea that is characterized by severe course, which is difficult to treat with conservative therapy. On the base of the disease is a violation of water-salt metabolism due to damage of the endothelium of the cornea – monolayer cells, which covers the posterior corneal surface rights. These cells perform barrier function: they prevent the penetration of intraocular fluid into the thickness of the cornea. The feature of endothelial cells – they are impossible to be restored. In other words, if some cells die because of inflammation or injury, the cells which left are not able to fully implement trophic of the cornea, the last one swells, loses transparency. Patients suffer from vision deterioration and severe pain syndrome develops. This serious disease develops as a result of carried inflammatory diseases (uveitis, iridocyclitis, keratitis of different etiology). Often the disease is accompanied by increased intraocular tension.
Medication treatment of endothelial-epithelial corneal dystrophy focuses on reversal of major symptoms, and is usually ineffective. The most effective treatment - penetrating or posterior lamellar keratoplasty.
Bullous keratopathy is the most severe stage of endothelial-epithelial corneal dystrophy. It is characterized by bubbles in the epithelium and subepithelial layer of the cornea. It is more common among older people and has outlines of hereditary nature. It is developed while reducing the number of endothelial cells to the critical number – about 1 500 per 1mm ².