The eye has two lenses in its anterior part, the cornea and the crystalline lens. At the back, it has the “film”, where the images are focused (and “captured”), which is called retina.
These lenses must be clear and have the right curvature to focus the light passing through the eye to the retina, thus forming a clear image. “There are pathological conditions where the lenses are cloudy or have an abnormal curvature, with the result that the image in the retina is not formed properly and the patients’ vision is not good.”
What is keratoconus?
Keratoconus is the condition that affects the cornea, causing thinning and a change in its normal curvature, so the cornea acquires a conical shape instead of the normal spherical shape. This is how the disease got its name, which is called keratoconus or keratoconus. The cornea is the most powerful lens of the human eye, therefore changes in its normal curvature (from the keratoconus) significantly reduce patients’ vision. Keratoconus occurs in young patients, where, usually in the early stages, it is subclinical and does not cause any symptoms, such as decreased vision. Keratoconus can develop over time, causing frequent changes in the prescription of patients ‘glasses, as well as causing high and abnormal corneal astigmatism, thereby reducing patients’ vision.
The diagnosis of keratoconus
As mentioned above, keratoconus is not immediately noticeable, especially in its early stages, because with glasses a very high level of vision is achieved. Usually, it is the frequent changes in the prescription of the glasses, the high corneal astigmatism, and the reduced vision in one or even both eyes, that lead to more specialized clinical and imaging examinations, when the keratoconus is diagnosed. The most important test for both the diagnosis and the monitoring of keratoconus is the corneal tomography, in which the curvature of the cornea and its thickness are shown in detail.
Treatment and cure
The two main goals set for patients with keratoconus are: firstly, the stabilization of the disease, so that the disease does not worsen over time and, secondly, the improvement of vision with visual aids such as glasses and specialists contact lenses.
Corneal collagen cross-linking
For the last twenty years there is a possibility of intervention with surgical treatment, which achieves stabilization of the development of keratoconus at a high rate – over 90%. This treatment is called corneal collagen cross-linking, and has the ability to “harden” the cornea and prevent further thinning and change in its curvature. Corneal collagen cross-linking is now the treatment of choice for patients with progressive keratoconus and is a safe method performed under local anesthesia. The patient, after the surgical treatment, for two to three days has photophobia, discomfort, pain, as well as low vision, but after a week, he regains functional vision and after a month his / her vision returns to pre-surgery levels.
Vision correction
As mentioned above, changes in corneal curvature as well as corneal astigmatism reduce the visual acuity of patients with keratoconus, both quantitatively and qualitatively. Patients often complain of diplopia, difficulty driving at night, watching TV and at the same time difficulty reading. It is worth noting that, as in the initial stages the corneal deformity is not significant, the patient can achieve good restoration of vision with glasses or with the use of soft contact lenses. However, when the corneal deformity becomes significant, then the above optical aids do not offer functional vision and patients must seek more complex solutions. Today, there are a number of specialized contact lenses (sclerotic, hybrid, etc.) that after proper application can achieve excellent levels of vision for patients with clinically significant keratoconus.
Writes:
Mr. Vassilios F. Diakonis, Director of the Front Half
Ophthalmic Surgeon of the 2nd Ophthalmology Clinic Metropolitan Hospital
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