Eyelids and the Anterior Segment:
                     Case twenty

---

 
This 45 year-old man had had deteriorating right vision and ocular irritation for the past year. His vision and ocular irritation improved following the above procedure.

a. What does the picture show?

Band keratopathy treated with excimer laser.

b. What are the possible causes for his initial problem?

Band keratopathy is caused by deposition of calcium salt in the epithelial basement, Bowman's layer and the superficial stroma.
It can be caused by :

• Idiopathic

• Ocular disease
chronic uveitis
trauma
interstitial keratitis
phthisical bulbi
 
• Systemic condition causing hypercalcaemia
hyperparathyroidism
sarcoidosis
multiple myeloma
renal failure

c. What is the principle of the procedure that he had?

Excimer (excited dimer) laser produces radiation in the ultraviolet part of the electromagnetic spectrum which is used to photoablate a precise quantity of epithelium and stromal tissue. The photoablation is achieved mainly through dissociation of carbon-carbon bonds when the molecules absorb the laser.