Keratoconus is a degenerativ disorder of the eye in which structural changes within the cornea causes it to thin and grow to a more conical shape than its normal curve.

Keratoconus can cause substantial distortion of vision, with multiple images. If both eyes are affected the patient won´t be able to see clearly in the distance nor close by. 

Glasses won´t be able to correct the refractive defect enough to see clearly. Only hard contact lenses will be to correct the visual defect. 

To stop the keratoconus from progressing collagen cross-linking will help. In sever cases a cornea transplantion might be necessary.