Cornea is the first coat of eye which is transparent circular structure. Functionally it acts as a lens responsible for focusing rays inside the eye. It is an important optical structure through which rays of light enter the eye. Any damage or injury to this delicate structure can lead to permanent loss of corneal transparency or in other words cause clouding and opacification.
Loss of corneal transparency prevents the entry of light rays into the eye and reduces vision. In cases of severe of damage, this can cause total loss of vision making the person visually handicapped. There are other conditions also such as malnutrition, Vitamin A deficiency, infection, certain corneal diseases such as ‘keratoconus’ and ‘corneal degeneration’, which can cause corneal blindness.
Corneal disease is third largest cause of blindness or low vision in Indian population. Corneal disorders encompass a wide spectrum of diseases most common of these are pterygium, Keratoconus, corneal dystrophy, corneal tears, corneal oedema, infective keratitis, contact lens related keratitis, allergic keratoconjunctivitis, each of these diseases need methodical approach and specialized care.
Pterygium
Pterygium is a veil like lesion that usually occurs in exposed part of white of the eye. This grows slowly over the cornea (the central black portion) and can obstruct vision or deteriorate vision by inducing cylindrical power.
Treatment of Pterygium
Pterygium is not only cosmetically disfiguring but can affect the vision also. In view of this it is advisable to surgically excise it at the earliest. Surgical excision of pterygium is a simple day care procedure with no adverse effects.
Latest surgery method involves removing the pterygium tissue and placing a healthy tissue on bare area which prevents recurrence and is cosmetically very gratifying.
Surgery for pterygium is minimally invasive, and is very safe.
Pterygium does not respond to medical treatment of any kind be it in form of eye drops or ointment and surgical excision is the treatment of choice
Keratoconus is a progressive disease of the outer transparent layer of the eyeball (cornea) affecting young adults mostly in their twenties. It is characterized by progressive thinning of the normally round cornea causing it to bulge forward & assume a cone like shape. This irregularity in the cornea results in the formation of a distorted image of objects on the retina & gives rise to blurred vision.
Symptoms & signs of Keratoconus
- Keratoconus can be diagnosed at an early stage with detailed eye examination which includes Retinoscopy,
- Slit lamp examination & sophisticated tests like Topography to check the shape & curvature of cornea & Pachymetry to determine the thickness of the cornea.
Treatment Options
In early stages, when the cornea is still regular, corrective prescription glasses or soft contact lenses can help the patient. As keratoconus advances, the corneal surface becomes increasingly irregular & these options do not help adequately. In intermediate & advanced stage, various other treatment options & different types of contact lenses are available.
Rigid Gas permeable contact lenses : provide a smooth refractive surface replacing the irregular cone like surface of the cornea, thus enabling the patient to see clearly. Lens fitting in Keratoconus can be demanding & time consuming process. RGP lenses are not as comfortable as soft contact lenses.
Piggybacking Contact Lenses : a soft contact lens is first placed on cornea to give it a cushion like effect & RGP lens is fitted over it. Best features of both lenses are combined – makes the wearer comfortable & at the same time gives crisp & clear vision. The fitting should be perfect to ensure good oxygen permeability to the cornea as the patient will be wearing two lenses. However, with newer high oxygen permeable lenses this is not a problem.
Hybrid Contact lenses : uniquely designed wherein the central visual portion is made up of high oxygen permeable rigid material & peripheral anchoring portion is of soft hydrogel material. Maximizes the best features of both lenses & improves wearers comfort as well as visual performance in keratoconic eyes.
New Vistas In Surgical Treatment Of Keratoconous :Intacs (Intra Corneal Ring Segments)
Patients with moderate non progressive keratoconus who are intolerant to contact lenses are good candidates for INTACS. Use of INTACS not only improves the visual outcome it also reduces the dependency of patient on glasses or contact lenses. INTACS are rings made of inert material that are implanted in mid periphery of cornea . These rings significantly flatten the curvature of keratoconic cornea thus improving vision.
C3 – R (CORNEAL COLLAGEN CROSSLINKING)
Corneal collagen crosslinking with riboflavin is the latest addition to treatment options for early progressive keratoconus. This is minimally invasive day care procedure that stabilizes the keratoconus and prevents further deterioration of vision. With newer corneal topography equipments it is easy to pick up early keratoconus and C3R in such cases further progression of keratoconus and thus reduces visual morbidity. C3R is a safe procedure for early progressive keratoconus.
Penetrating Keratoplasty
This involves full thickness corneal transplantation, where the entire recipient cornea is replaced with full thickness donor cornea. This type of penetrating surgery is usually indicated for full thickness corneal opacity, failed grafts and macular corneal dystrophy. This type of surgery gives very good visual outcome but have along recovery period.
DALK (Deep anterior lamellar Keratoplasty)
This is one of the recent modification of keratoplasty where full thickness transplantation is not done. This type of transplantation involves replacing only the superior three diseased layers of cornea with healthy donor tissue .This procedure has faster recovery period and minimal risk of rejection. Also visual outcome is better. This surgery is indicated in cases with advanced Keratoconus, superficial scar.
Keratoplasty (Corneal Transplantation)
What is ‘Corneal Transplantation’?
Corneal transplantation / keratoplasty / corneal grafting is the surgical procedure that restores sight in patients suffering from corneal blindness. In this surgical procedure, the diseased opaque cornea is replaced by a clear healthy donor corneal tissue which restores sight by allowing the light rays to enter the eye through transplanted clear cornea. This procedure of corneal grafting is possible only on the availability of donor cornea by process of eye donation. By donating eyes after death a human being can restore sight to a blind person. This gift of sight is invaluable for these visually handicapped persons.
Different Techniques of Keratoplasty Penetrating keratoplasty (Corneal Transplantation):
This involves full thickness corneal transplantation, where the entire recipient cornea is replaced with full thickness donor cornea. This type of penetrating surgery is usually indicated for full thickness corneal opacity, failed grafts and macular corneal dystrophy. This type of surgery gives very good visual outcome but have a long recovery period.
DALK (Deep anterior lamellar Keratoplasty)
This is one of the recent modification of keratoplasty where full thickness transplantation is not done. This type of transplantation involves replacing only the superior three diseased layers of cornea with healthy donor tissue . This procedure has faster recovery period and minimal risk of rejection. Also visual outcome is better. This surgery is indicated in cases with advanced Keratoconus, superficial scar.
DSEK (Descemets stripping endothelial keratoplasty)
DSEK is the most recent addition to the armamentarium to treat endothelial disease of cornea. This modification in keratoplasty replaces the diseased descemets and endothelium with healthy donor endothelium , descemets’ membrane and posterior stroma and requires no sutures. As this procedure is sutureless it has several advantages like faster recovery, better visual outcome and less risk of suture infection.
Descemet’s Membrane Endothelial Keratoplasty (DMEK)
Descemet membrane endothelial keratoplasty (DMEK) is the most recent solution to treat the decreased vision due to corneal oedema seen in Fuchs dystrophy, bullous keratopathy, and other causes of poor corneal endothelial function. There are three generations in the evolution of corneal transplantation and DMEK is the third and latest.
In DMEK the diseased innermost layer of the cornea is removed surgically and the corresponding thin layer from a healthy donor cornea is put in its place. The thin delicate transplant is secured with only an air bubble. The surgery can be combined with cataract surgery for patients who require both.
DMEK provides quick improvement in vision with reduced risk of rejection making it keratoplasty of choice in patients with corneal oedema.
Contact shreeji Eye Institute for all your cornea surgery or treatment. Call us at (+91) 8425855150