Eye therapy system
Embodiments apply a cross-linking agent to a region of corneal tissue. The cross-linking agent improves the ability of the corneal tissue to resist undesired structural changes. For example, the cross-linking agent may be Riboflavin or Rose Bengal, and the initiating element may be photoactivating light, such as ultraviolet (UV) light. In these embodiments, the photoactivating light initiates cross-linking activity by irradiating the applied cross-linking agent to release reactive oxygen radicals in the corneal tissue. The cross-linking agent acts as a sensitizer to convert O 2 into singlet oxygen which causes cross-linking within the corneal tissue. The rate of cross-linking in the cornea is related to the concentration of O 2 present when the cross-linking agent is irradiated with photoactivating light. Accordingly, the embodiments control the concentration of O 2 during irradiation to increase or decrease the rate of cross-linking and achieve a desired amount of cross-linking.
1. A system for controlling cross-linking in corneal tissue, comprising:
a cross-linking system configured to apply a cross-linking agent to a cornea and activate the applied cross-linking agent to cause cross-linking in corneal fibrils of the cornea;
a monitoring system configured to determine an amount of cross-linking in the cornea; and
a delivery device configured to selectively adjust an O 2 content provided to the cornea to control the rate of cross-linking in response to the amount of cross-linking in the cornea determined by the monitoring system.
2. The system according to claim 1 , wherein the delivery device is configured to provide a gas mixture that determines the O 2 content provided to the cornea.
3. The system according to claim 1 , wherein the delivery device is configured to provide an oxygenated substance to the cornea, the oxygenated substance increasing the O 2 content in the corneal tissue when the oxygenated substance is applied.
4. The system according to claim 3 , wherein the oxygenated substance includes Riboflavin.
5. The system according to claim 3 , wherein the oxygenated substance includes a gel that is saturated or supersaturated with O 2 .
6. The system according to claim 5 , wherein the oxygenated substance includes the cross-linking agent and the gel.
7. The system according to claim 1 , wherein the monitoring system is configured to determine the stiffness of the corneal tissue.
8. A system for controlling cross-linking in corneal tissue, comprising:
a vessel that stores an oxygenated substance under O 2 pressure greater than ambient increasing the equilibrium concentration of O 2 for the oxygenated substance and causing the oxygenated substance to be saturated or supersaturated with O 2 ;
a delivery device configured to apply the oxygenated substance to corneal fibrils in the corneal tissue, the oxygenated substance increasing the O 2 content in the corneal tissue when the oxygenated substance is applied; and
a cross-linking system including a light source configured to activate a cross-linking agent applied to the corneal fibrils in the corneal tissue, the activated cross-linking agent causing cross-linking in the corneal fibrils.
9. The system according to claim 8 , wherein the oxygenated substance includes a gel.
10. The system according to claim 8 , wherein the oxygenated substance is mixed with the cross-linking agent before the oxygenated substance and the cross-linking agent are applied to the cornea.
11. The system according to claim 8 , wherein the delivery device is configured to apply the oxygenated substance to the cornea before the cross-linking agent is applied to the cornea.
12. The system according to claim 11 , further comprising an applicator configured to apply the cross-linking agent to the cornea.
13. The system according to claim 12 , wherein the applicator is an eye dropper or a syringe.
14. The system according to claim 8 , wherein the cross-linking agent is the oxygenated substance, the vessel storing the cross-linking agent under O 2 pressure greater than ambient that increases the equilibrium concentration of O 2 for the cross-linking agent causing the cross-linking agent to be saturated or supersaturated with O 2 , the delivery device applying the cross-linking agent to the corneal fibrils.
15. A system for controlling cross-linking in corneal tissue, comprising:
a cross-linking system configured to activate a cross-linking agent applied to a cornea to cause cross-linking in corneal fibrils of the cornea, the cross-linking system including a light source configured to direct a photoactivating light to the cornea; and
a delivery device configured to selectively increase or decrease an O 2 content provided to the cornea to control the rate of cross-linking, wherein the delivery device is configured to selectively increase or decrease the O 2 content based on an assessment of the structure of the cornea.
16. The system according to claim 15 , further comprising an applicator configured to apply the cross-linking agent to the cornea, the delivery device being configured to separately apply a gas mixture or an oxygenated substance to the cornea to control the rate of cross-linking.
17. The system according to claim 15 , wherein the delivery device is configured to apply the cross-linking agent to the cornea, the cross-linking agent being saturated or supersaturated with O 2 such that the cross-linking agent increases the O 2 content in the cornea when the cross-linking agent is applied.
18. The system according to claim 17 , wherein the delivery device is a syringe.
19. The system according to claim 15 , wherein the delivery device is configured to apply a mixture of a cross-linking agent and an oxygenated substance to the cornea to increase the O 2 content in the cornea, the oxygenated substance being saturated or supersaturated with O 2 .
20. The system according to claim 15 , further comprising a monitoring system configured to provide the assessment of the structure of the cornea.