5d • General discussion
Therapeutic laser in keratoconus to improve quality of vision.
Cross linking often stops progression of keratoconus, however does not improve refractive outcomes. PTK (phototherapeutic keratectomy) uses the same excimer laser used in LASIK and PRK. This laser can be combined with cross-linking in keratoconus patients with a suitable cornea to improve the topography and optics. PTK can be performed at the time of cross-linking to reduce corneal surface irregularities. PTK helps reduce higher-order aberrations and can lead to improved corneal topography and enhanced quality of vision. Suitable patients are those with a pachymetry greater than 450um and lower levels of irregular astigmatism. PTK can also be performed after cross-linking.
Below is a case study of patient:
History:
21 year old lady with keratoconus progression.
We planned to perform a PTK of 50um to reduce the irregularity over the cone. The amount of microns is determined by the epithelial map which allows us to precisely remove a specific depth of epithelium and irregular stroma. Based on this epi map we have decided to go with 50um to remove the epithelium. This was followed by a standard cross-linking.
Traditionally in crosslinking we use alcohol to remove the epithelium.
Post operative:
One can note that the axial map is improved showing reduced K readings. The refraction and visual acuity have also improved:
Refraction:
Pre Op L) -4.00/-6.00X141
Post Op L) -4.50/-4.75X145
Visual Acuity:
Pre Op VAL) 0.6
Post Op VAL) 0.7
Patients undergoing crosslinking combined with PTK will often have good best corrected visual acuity with spectacles and improved quality of vision
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Therapeutic laser in keratoconus to improve quality of vision.
