Light and images of objects are refracted by the cornea and lens of the eye to reach the spots of vision on the retina. In a normal eye, light beams coming from the outside are refracted by the cornea and lens to reach the visual cortex, which provides visual acuity.
Refractive errors may cause defects in the cornea, lens, retina, or optic nerve. Persons suffering from refractive error are advised to get their eyes and eyegrounds regularly examined each year.
The most important symptoms of refractive errors are vision disorders, eye pain, and discomfort in the eyes. The types of refractive error are referred to as shortsightedness (myopia), farsightedness (hypermetropia), unequal curvature of the eye's horizontal or vertical refractive elements (astigmatism), and age-related farsightedness (presbyopia).
Diverse alternatives are available to achieve sharp vision in persons with refractive errors. The options available for refractive error correction include eyeglasses, contact lenses, or treatment by excimer laser. Furthermore, the eye examination may help to diagnose retinal detachment, hypertension, brain tumor, and symptoms of diverse diseases in the body.
Cataract and its treatment (Phacoemulsification)
Cataract is the clouding of the normally clear lens of the eye. In 90% of these cases, cataract is age related, but it may be seen in all age groups including infants. The most frequently seen symptoms of cataract are painless visual loss, glare or increased sensitivity to light, paling or yellowing of colors, and deteriorated night vision.
The only treatment option for cataract is surgery. At our hospitals, cataract surgery is performed using the Phaco (Phacoemulsification) technique, which is the current state-of-the-art worldwide. The quality and type of the lens inserted in the eye are the most important factors that affect the success of this surgery. The intraocular lenses used at our hospitals are FDA-approved and comprise special coatings and filters of aspheric design.Multifocal/trifocal intraocular lenses may also be used if preferred by the patient.
Glaucoma and its treatment (high eye pressure)
Glaucoma is caused by insufficient drainage of intraocular fluid due to structural clogging of the eye's drainage system, resulting in increased eye pressure which causes damage to and death of the optic nerve. High eye pressure is an insidious disease that may result in sudden blindness without giving any symptoms. The symptoms of glaucoma include blurred vision, severe eye pain, headache, nausea, vomiting, and glare.
The most efficient method to detect glaucoma is regular eye examinations by an eye doctor. The loss of vision caused by glaucoma is irreversible. Options to prevent further loss include eye drops, laser surgery (argon laser), and surgical intervention. The examination methods available to determine the current condition of the optic nerve are Optical Coherence Tomography (OCT), Nerve Fiber Analyzer (NFA), corneal pachymetry, and computerized visual field.
The Pediatric Autorefractometers used in some of our clinics provide a convenient means of examination for children. Thus, it will suffice for the child to look at a disk with light source from a meter's distance will suffice to take the required measurements. Routine examinations are advised for newborns, and at the ages of 1 and 3. These examinations play a very important role in the diagnosis and treatment of eye problems especially in children that have impaired vision history in their family.
Strabismus is the failure of the two eyes to maintain their proper alignment when looking at a certain point. The causes of strabismus may include failure to wear eyeglass even though needed, anomality of the muscles controlling the movement of the eyes, or congenital or neurological problems.
Inward deviation (Esotropia)
Outward deviation (Exotropia)
Downward deviation (Hypotropia)
Upward deviation (Hypertropia)
The aim of strabismus treatment is to improve vision, correct the head position, eliminate double vision, procure eye movement, and resolve aesthetic complaints. Strabismus is treated by surgical methods.
This branch is associated with the introversion or extroversion of the eyelid, correction of wrinkles around the eye, correction of under-eye bags, surgical treatment of lacrimal duct obstructions, correction of congenital, age-related or post-traumatic malformations of the eyelid, ocular prostheses, and treatment of eye tumors.
What does retina, vitreous and macula mean?
The retina is the sensory membrane that lines the inner surface of the back of the eyeball and consists of millions of photoreceptor cells, allowing the brain to perceive images. The perceived image is transported to the brain by way of the optic nerve, thus creating vision. If we would compare the eyeball with a camera, the retina would be the sensor on which the light reflects. The midmost section of this sensor allowing for central and sharp vision is referred to as the macula, whereas the glairy fluid filling the eyeball is called vitreous. Diseases and conditions of the retina and vitreous are often interconnected.
What are the most common retinal diseases ?
Retinal break and retinal detachment
Age-related macular degeneration (yellow spot disease)
Epiretinal membrane (macular pucker)
Retinal vein occlusions
Retinal artery occlusions
Which procedures and tests are applied during retinal examination ?
Fundus Fluorescein Angiography (FFA)
Optical Coherence Tomography (OCT)
Methods used to treat retinal diseases
These are surgeries related to the intraocular gel-like clear structure, referred to as vitreous filling the inner chambers of the eye, and the retina. The vitreous may degenerate and result in loss of vision by various reasons (such as trauma, diabetes, uveitis, intraocular bleeding etc.). Membranes may build up in the vitreous, which may create a pulling effect on the retina, thereby giving rise to retinal break and retinal detachment. Besides, holes may occur in the macula, which is responsible for central vision, along with thin membranes on the macular surface. All these degenerations can be treated surgically. In this surgical procedure, the vitreous humor is removed by penetrating into the insides of the eye with special instruments under a microscope with the help of retinal imaging systems and replaced by special balanced solutions, bleedings are stopped, any membranes covering the retinal surface are stripped off, and attachment of the retina is restored by draining any fluids that have accumulated under the retina in cases of retinal detachment. This procedure is microsurgical, during which use is made of laser, various dyes to dye the membranes, and buffer substances like silicone or gas. These are seamless surgeries, which provide anatomic and functional restoration.
INTRAVITREAL ANTI-VEGF THERAPIES
Intraocular drug deliveries referred to as anti-VEGF are applied in cases of diabetic retinopathy and age-related macular degeneration (yellow spot disease). The intraocular drug is delivered every 4 to 6 weeks
This therapy is applied in operating room environment to minimize any infection risks. It is generally painless, since the eye is anesthetized by means of special eyedrops. Some patients may feel mild stinging pain for a short time.
ARGON LASER PHOTOCOAGULATION
Another significant treatment method is laser treatment in cases where diabetic macular edema, new vessel formations (proliferative diabetic retinopathy, or retinal breaks are detected. It is desirable that this procedure is performed on cases where there is no intraocular bleeding. The procedure may not be performed if there is too much intraocular bleeding.
CORNEAL TRANSPLANT (KERATOPLASTY)
What is cornea?
The cornea is a clear, dome-shaped tissue located in the front part of the eye's outer layer. The iris, which is the colored part of the eye, is located right beneath this clear structure. The cornea has two major functions. First, to protect the structures inside the eyeball, and second, to refract the light rays and focus them exactly on the nerve structure responsible for vision, which is referred to as retina. The cornea has the highest refractive index among all structures of the eye. Therefore, the clouding or deformation of the cornea is always associated with severe visual impairment.
What does corneal transplant mean ?
Corneal transplantation is a surgical procedure where the clouded or deformed corneal tissue is replaced by healthy corneal structure taken from a deceased donor. Colloquially, eye transplantation is mistakenly used to express corneal transplantation. What the current medical possibilities allow for is the transplantation of the cornea, i.e. transplantation of the entire eyeball is not possible.
Why are corneal transplants performed ?
The normally clear and veinless corneal tissue may become clouded by various reasons such as formation of scar tissue or edema (swelling). The clouding of the cornea prevents the proper refraction of light ray, which results in impaired vision. In some cases, severe pain may accompany corneal clouding. Corneal transplantation is performed to restore vision, decrease pain, or preserve the integrity of the eye.
Under which circumstances may a corneal transplant be necessary?
If the cells which ensure that the cornea stays clear get damaged or if the cornea becomes clouded subsequent to eye surgery
If the dome shape of the cornea gets deformed, e.g. becomes conical (keratoconus)
In case of certain inherited corneal diseases
Formation of scar tissue or new vessels in the cornea due to infection (for instance: subsequent to herpes simplex virus keratitis)
If the cornea becomes cloudy or its integrity is severely damaged due to an accidents
If the body rejects the transplant subsequent to corneal transplantation
RETINOPATHY OF PREMATURITY
Retinopathy of prematurity is defined as one of the most important health problems that may affect the eyes of premature babies. The vessels in the eyes of infants continue to develop until the baby is born. This development is interrupted in premature babies and continues after birth. The high concentrations of oxygen administered to premature babies in order to keep them alive may cause abnormal development of vessels in their eyes, resulting in Retinopathy of Prematurity, shortly referred to as ROP, in the retina of babies whose vessel development is not completed in the womb. If not treated in early stages, ROP may cause blindness in both eyes. Therefore, premature babies must be examined by an ophthalmologist.
In which babies is Retinopathy of Prematurity most frequently seen ?
The duration of a normal pregnancy is 40 weeks, or in other words 280 days. A baby is considered to be premature if born before the 37th week of gestation. Babies born with a weight below 2.500 grams are referred to as low-birthweight babies. Two-thirds of these babies are premature.
The group in which ROP is most frequently seen is those born under 1.000 grams. Therefore, ROP examination is an absolute must for all babies born under 1.500 grams before they reach 32 weeks of gestation. Early diagnosis and treatment of ROP in newborns is only possible through collaboration between specialized pediatrists and ophthalmologists. Other factors that may increase the risk of retinopathy are pulmonary or cardiovascular disorders, severe infections, and problems regarding the brain. While treatable if diagnosed early, ROP will result in blindness of both eyes if its diagnosis is belated.
When should the babies get their eyes examined ?
Eye examination must be performed 4 to 6 weeks after delivery. The treatment success of ROP, which has five different stages from mild to severe, depends on the stage at which the disease is diagnosed. While mere follow-up is sufficient in the first two stages, intravitreal anti-VEGF injection, laser treatment or cryotherapy must be initiated starting from stage three. This is because the best treatment results can be obtained in stage three, whereas the required surgical procedures in stage four and five generally fail to deliver the desired results. Getting the eyes of all newborn babies examined in their first month of life is essential not only for the timely diagnosis and successful treatment of ROP, but also many other eye diseases, high eye pressure, amblyopia, lacrimal duct obstruction, and strabismus.