Depending on the area of the cornea affected, we distinguish:
- Papillary cone (small: 5 mm at the center),
- Oval cone (large, below center and often sagging),
- General cone (covering more than 75% of the cornea, or keratoglobus).
Depending on the size of the corneal bulge, we distinguish:
- Mild cone (< 48 D),
- Moderate cone (up to 54 D),
- Heavy cone (> 54 D).
Taking into account such parameters as:
- corneal thickness,
- The size and location of the uplift,
- The presence of scars,
- Vogt line, Fleischer ring,
- The risk or presence of hydrops (a characteristic swelling in which if there is a rupture of Descemet ‘ s membrane and leakage of aqueous fluid into the stroma, which leads to corneal scarring
We classify the corneal cone on a scale from I to IV.
I – subclinical form, observed changes in corneal topography,
II – early form, in addition, mild changes in corneal morphology, no scarring
III – moderate form, Vogt’s lines present, Fleischer’s ring, changes in corneal morphology, no scarring
IV – severe form, corneal power above 55D, numerous scars
To assess the condition of the patient’s eyes, a comparison is made between the results of an individual corneal topography, such as from a year ago and from the current examination. Depending on the changes that have occurred during this time, measures are taken to stop the changes occurring in the cornea.
Corneal cone therapy proceeds in two stages:
- Stopping the progression – and in some cases reversing – of lesions.
- The aim is for the patient to achieve the greatest possible visual acuity. If the corneal relief is small, soft contact lenses are used, when the relief is large hard lenses come into play.
CROSS-LINKING (named after the effect it produces) – also known as cross-linking, corneal cross-collagenization or CXL – causes the cornea to stiffen and increase its mechanical resistance. The stiffening of the cornea is accomplished by increasing the number of bonds between the collagen fibers that build it. It occurs under the influence of UVA irradiation of the cornea.
In order to increase the sensitivity of the superficial layers of the cornea to UVA radiation, it is soaked in a special photosensitizing substance, riboflavin (vitamin B2). Clinical studies confirm that the action of riboflavin contributes to slowing or stopping the disease and, in some cases, its regression. Thus, the procedure makes it possible to bypass corneal transplantation.
If this too is unsuccessful, surgical treatment is used:
- corneal transplant
- Corneal ring implantation (Intacs) – small incisions are made in the corneal stroma and thin arched implants are placed to form a ring that exerts pressure on the curvature of the cornea, flattening the apex of the cone so it takes on a more normal shape.
