WO2008042891A2

WO2008042891A2 - Chitosan ophthalmic devices and methods

Info

Publication number: WO2008042891A2
Application number: PCT/US2007/080173
Authority: WO
Inventors: Kenton W. Gregory
Original assignee: Oregan Biomedical Engineering Institute, Inc.
Priority date: 2006-10-02
Filing date: 2007-10-02
Publication date: 2008-04-10
Also published as: WO2008042891A3

Abstract

Embodiments of the present invention provide methods and devices for treating and preventing eye infections. More specifically, embodiments of the present invention provide methods and devices for treating eye infection using chitosan based ophthalmic lenses.

Description

Chitosan Ophthalmic Devices and Methods

Related Applications

[0001] This application claims the benefit of U.S. Provisional Application Serial

No. 60/848,689, filed on October 2, 2006, the contents of which are incorporated herein by reference in its entirety.

Technical Field

[0002] Embodiments of the present invention relate to the field of ophthamology, and, in particular, to methods and devices for preventing and treating eye infections or diseases.

Background

[0003] In recent years increased contact lens use and poor ocular hygiene practices have contributed to increased rate of occurrences of bacterial eye infections. Microbial Keratitis and Conjunctivitis are eye infections that are common for, but not limited to, contact lens wearers. Common bacteria, such as Staphylococcus aureus and Klebsiella pneumoniae can cause symptoms ranging from itching and redness to permanent conditions such as blindness. Thus, it has become increasingly important to provide patients with more reliable and effective treatment.

[0004] Chitosan is an abundant polysaccharide compound derived from chitin, which exhibits antimicrobial properties and can thus be used to combat microbial eye infections. In addition, preliminary research demonstrates that chitosan has a similar ability to inactivate viruses. These findings indicate the strong potential that chitosan can inactivate bacteria and viruses in a variety of applications. The antipathogenic nature, low toxicity and wound healing capabilities of chitosan make it a promising candidate for antimicrobial applications, such as eye infections. [0005] Current methods for eye infection such as eye drops, ointments and oral antibiotics have undesirable side effects. Antibiotics can cause allergic reactions, and may increase the risk of secondary infection by non-susceptible bacteria or fungi. In addition, bacteria might develop resistance to antibiotic medications. Although direct application such as eye drops delivers high concentrations of antimicrobial agents to the surface of the eye with minimal systemic exposure to the agent, antibiotics rapidly dissipate from the tear film resulting in poor intraocular penetration. Consequently, intensive and longer-lasting application of topical agents is necessary for successful treatment. Moreover, patients find it difficult and inconvenient to follow a careful antibiotic treatment schedule, thus decreasing the efficacy of prescribed medication. Since contact lenses are usually habitually applied, chitosan coated lens therapy might prove to be more effective in battling bacterial eye infections. [0006] There is always a substantial risk for infection of the eye when inserting artificial components such as a contact lens. As a result, medical practitioners and contact lens wearers desire better ways to treat or prevent bacterial infections. The most devastating of these bacterial infections is microbial keratitis, which if left untreated for over 48 hours can cause permanent blindness or may require a corneal transplant in order to treat successfully.

[0007] Microbial keratitis is a disease that can be caused by several strains of bacteria. The most common bacteria that cause this condition are from the micrococcae family (staphylococcus, micrococcus), the enterobacteriaceae family, (citrobacter, klebsiella, enterobacter, serratia, proteus), and the streptococcus and pseudomonas species. This spectrum of bacteria covers both gram-positive and gram- negative bacteria species that invade host cells by toxin secretion or direct attack of cell membranes respectively. Various fungi may also contribute to Microbial keratitis, including species of Aspergillus, Alternaha and Phialophora

[0008] Microbial keratitis is a severe threat to the eye that occurs when bacteria bind to a cornea. Keratitis-causing bacteria can permeate the mucus and glycocalyx layers of the cornea and infect corneal cells. Keratitis occurs more frequently when the cornea is scratched, something that can occur due to improper placement of a contact lens. Currently, treatment cannot begin until the patient detects pain in his or her eye and seeks medical treatment. A bactericidal or bacteriostatic contact lens that can treat keratitis may provide a non-invasive treatment option for the patient. Thus, there is a need for more effective and convenient eye infection therapy.

Summary

[0009] In a first aspect, the invention provides an ophthalmic lens comprising chitosan for treating eye infections, wherein the ophthalmic lens is capable of substantially inactivating one or more pathogens.

[0010] In a second aspect, the invention provides a method of making an ophthalmic lens capable of substantially inactivating one or more pathogens, comprising forming a chitosan layer on at least a portion of a surface of the ophthalmic lens. [0011] In a third aspect, the invention provides a method of treating an eye infection comprising contacting the eye with an ophthalmic lens comprising chitosan.

Brief Description of the Drawings

[0012] Embodiments of the present invention will be readily understood by the following detailed description in conjunction with the accompanying drawings. To facilitate this description, like reference numerals designate like structural elements. Embodiments of the invention are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings.

[0013] FIG. 1 a illustrates selected aspects of an ophthalmic lens in accordance with embodiments of the present invention;

[0014] FIG. 1 b illustrates selected aspects of another ophthalmic lens in accordance with embodiments of the present invention;

[0015] FIG. 1 c illustrates selected aspects of yet another ophthalmic lens in accordance with embodiments of the present invention; and

[0016] FIG. 2 illustrates a flowchart of a method for making an ophthalmic lens in accordance with embodiments of the present invention.

[0017] FIG. 3: Spin-Coater set-up. A sample to be spin-coated is placed in the center of the spin-coater, see red arrow, and is rotated on the disk. It is held in place by vacuum suction.

[0018] FIG 4: Diagram of Spin-Coating. Note how the chitosan solution moves up the contact lens as the lens is spinning during the spin coating process. The image on the right shows the chitosan ring that is formed on the lens as a result of spin coating. [0019] FIG. 5: Schematic of SEM imaging location

[0020] FIG. 6: SEM images of chitosan-coated contact lenses, (a) chitosan on a soft lens; (b) image of chitosan on same lens as (a), but taken from a different location (c) chitosan on a rigid lens; and (d) same as (a) and (b) but with increased magnification.

[0021] FIG. 7: SEM images of lens surface without chitosan. (a) Image of the edge of a noncoated, lyophilized lens showing lack of chitosan presence; (b) image of the edge of a chitosan-coated lens showing no chitosan on the edge of the lens.

[0022] FIG. 8: Confocal images of chitosan on soft lenses. Chitosan appears green because of the fluorescein presence. This figure displays two pictures of chitosan found in different places on the ring of the same lens.

[0023] FIG. 9: Confocal images of chitosan dissipation in aqueous saline environment. This figure shows the green structure becomes dimmer over time suggesting the chitosan is dissipating off the lens.

[0024] FIG. 10: Thickness of Layer, a) A side view of the chitosan layer on the lens when initially submerged in saline; b) the side-view of the chitosan layer after 12 hours. It is seen that the layer is significantly thinner, but still present after 12 hours in an aqueous saline environment.

[0025] FIG. 11 : Air-dry. A) 0 hours of dissipation; b) 6 hrs of dissipation c) 12 hrs of dissipation.

[0026] FIG. 12: Soft Lens Spectrophotometer Set Up.

[0027] FIG. 13: Light Transmittance (LT %) graphical output from spectrophotometer. This graph is showing the light transmittance of a Focus Night &

Day (Lotrafilcon A) contact lens that has not been coated with chitosan. This can be used for comparison of light transmittance for a chitosan coated Night &Day lens. [0028] FIG. 14: Light Transmittance (LT%) Data for Focus Night & Day Lens with

20 μL Chitosan Layer. This can be compared to FIG. 13 and noted very little difference between the two transmittance graphs.

[0029] FIG. 15: Resultant stress/strain curve for Lotrafilcon A lenses, both coated and uncoated. Control #1 and #2 correspond to un-coated lenses, and coated lens #1 and #2 correspond to chitosan coated lenses. The ultimate tensile stresses are tabulated in Table 2.

[0030] FIG. 16: Antibacterial Activity Results for 20 μL Prototype against

Staphylococcus: Prototype Lens with Chitosan on the Left and Control Lens without

Chitosan on the Right.

[0031] FIG. 17: Antibacterial activity comparison results for 20 μL and 10 μL volumes of chitosan against S. aureus.

[0032] FIG. 18: Antibacterial activity results for 20 μL prototype against P. mirabilis: prototype lens on the left and control lens on the right.

Detailed Description of Embodiments of the Invention [0033] In the following detailed description, reference is made to the accompanying drawings which form a part hereof wherein like numerals designate like parts throughout, and in which is shown by way of illustration embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and structural or logical changes may be made without departing from the scope of the present invention. Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of embodiments in accordance with the present invention is defined by the appended claims and their equivalents. [0034] Various operations may be described as multiple discrete steps in turn, in a manner that may be helpful in understanding embodiments of the present invention; however, the order of description should not be construed to imply that these operations are order dependent.

[0035] The description may use the phrases "in an embodiment," or "in embodiments," which may each refer to one or more of the same or different embodiments. Furthermore, the terms "comprising," "including," "having," and the like, as used with respect to embodiments of the present invention, are synonymous. [0036] In various embodiments of the invention, methods and devices for preventing and treating pathogenic eye infections are provided. The term "pathogen" or "pathogens" is intended to refer to any bacterium, virus, fungus or other microorganism that can cause disease. The term "inactivate" is intended to refer to rendering a toxic agent ineffective or harmless. [0037] Although certain embodiments have been illustrated and described herein for purposes of description of the preferred embodiment, it will be appreciated by those of ordinary skill in the art that a wide variety of alternate and/or equivalent embodiments or implementations calculated to achieve the same purposes may be substituted for the embodiments shown and described without departing from the scope of the present invention. Those with skill in the art will readily appreciate that embodiments in accordance with the present invention may be implemented in a very wide variety of ways. This application is intended to cover any adaptations or variations of the embodiments discussed herein. Therefore, it is manifestly intended that embodiments in accordance with the present invention be limited only by the claims and the equivalents thereof.

[0038] In a first aspect, the invention provides an ophthalmic lens comprising chitosan for treating eye infections, wherein the ophthalmic lens is capable of substantially inactivating one or more pathogens. FIG. 1 a is a cross-sectional diagram illustrating selected aspects of an ophthalmic lens in accordance with embodiments of the present invention. As shown, an ophthalmic lens 102 comprising chitosan 104 is provided. In various embodiments, ophthalmic lens 102 may be a contact lens. The contact lens selected for ophthalmic lens 102 may be a rigid gas permeable lens, a soft lens or a hybrid rigid/soft lens. In various embodiments, ophthalmic lens 102 may be a hydrogel lens or a non-hydrogel lens.

[0039] The term "chitosan" generally refers to a deacetylated derivative of chitin.

The term "chitosan" may include both ideal chitosan, which is a linear polysaccharide of β-(1 -4)-2-amino-2-deoxy-D-glucopyranose, as well as any chitin/chitosan co-polymer such as linear polysaccharides composed of distributed β-(1-4)-linked D-glucosamine (deacetylated unit) and N-acetyl-D-glucosamine (acetylated unit). Chitosan has three crystalline forms, α, β, and γ. The chitosan may be α-chitosan, β-chitosan or γ-chitosan. [0040] In various embodiments, the term "chitosan" may also include one or more derivatives of chitosan, such as derivatives of chitosan functionalized with an amino acid. For example, the free amine on chitosan may be functionalized with arginine ("chitosan-arginine") or guanidine ("chitosan-guanidine"). Any one or any mixture of two or more of the above chitosan and/or chitosan derivatives may be capable of contacting, absorbing and/or binding a toxic agent, or combination of toxic agents, thereby inactivating the toxic agent(s).

[0041] In various embodiments, chitosan 104 may comprise a chitosan copolymer, chitosan beads, chitosan gels/hydrogels, chitosan films or other chitosan biomatehals. In embodiments, chitosan 104 may include chitosan grafted with other biopolymers (e.g. carbohydrate macromolecules) or synthetic polymers. [0042] In an embodiment, ophthalmic lens 102 may be impregnated with chitosan

104. In another embodiment, ophthalmic lens 102 may comprise a co-polymer including chitosan 104. In an embodiment, chitosan 104 may be crosslinked to ophthalmic lens 102.

[0043] In various embodiments, chitosan 104 may be a bactericidal, bacteriostatic, fungicidal, fungistatic, viricidal, and viralstatic agent. Thus, ophthalmic lens 102 may be capable of substantially inactivating one or more pathogens. As used herein, the terms "substantial" or "substantially" generally refer to inactivating one or more pathogens sufficient to have a therapeutic effect as compared to a ophthalmic lens not having chitosan.

[0044] In various embodiments, chitosan 104 may be optically transparent.

[0045] As shown in FIG. 1 b, ophthalmic lens 102 may comprise chitosan layer

106 such that chitosan layer 106 covers at least a portion of a surface 108 on ophthalmic lens 102. In such an embodiment, chitosan layer 106 may include chitosan 104. For such embodiments, chitosan layer 106 may be optically transparent. [0046] As shown in FIG. 1 c, chitosan layer 106 may form a donut shaped pattern on surface 108, leaving a center region 110 of surface 108 uncoated. According to such an embodiment, center region 110 remains optically transparent. [0047] In various embodiments of the present invention, ophthalmic lens 102 may be used to treat eye infections, including, but not limited to, Microbial keratitis. In such embodiments, ophthalmic lens 102 may be capable of substantially inactivating species of Streptococcus, Staphylococcus, Pseudomonas, Enterobacteriaceae, Serratia, or Acinetobacter. In various embodiments, ophthalmic lens 102 may be capable of substantially inactivating species of Aspergillus, Alternaria and Phialophora. [0048] FIG. 2 illustrates a flowchart of a method for making an ophthalmic lens in accordance with embodiments of the present invention. In block 202 a chitosan solution may be applied to at least a portion of a surface of an ophthalmic lens to form a chitosan layer. In various embodiments, the ophthalmic lens may be a contact lens. [0049] In a second aspect, the invention provides a method of making an ophthalmic lens capable of substantially inactivating one or more pathogens, comprising forming a chitosan layer on at least a portion of a surface of the ophthalmic lens. In exemplary embodiments, the chitosan solution may applied by spraying, dipping, electro-spinning, or some combination of these. In an embodiment, the chitosan solution is polymerized in situ to form the chitosan layer.

[0050] In exemplary embodiments, the chitosan solution comprises a concentration of chitosan in the range of 0.001 % to 6% by weight. In an embodiment, the chitosan solution may be an acetic acid solution. In other embodiments, the chitosan solution may comprise one or more salts.

[0051] In various embodiments of the present invention, the chitosan solution forms a bactericidal, bacteriostatic, fungicidal, fungistatic, viricidal, or viralstatic layer. In other embodiments, the chitosan solution forms an antiviral layer.

[0052] In an embodiment of the present invention, spin coating may be used to apply the chitosan solution to the surface of an ophthalmic lens. In an embodiment of the present invention, the chitosan solution may form a pattern on the surface of an ophthalmic lens such that a center region of the surface remains exposed. Such a pattern may be, but not limited to, a donut shaped pattern.

[0053] In block 204, the ophthalmic lens is lyophilized to attach the chitosan layer to the ophthalmic lens. In another embodiment, the chitosan may be crosslinked to the ophthalmic lens.

[0054] In a third aspect, the invention provides a method of treating an eye infection in a vertebrate, comprising contacting the eye with an ophthalmic lens comprising chitosan. In some embodiments, the vertebrate is a mammal. For purposes of this invention, the term "mammal" is expressly intended to include humans. [0055] In various embodiments, the eye infection to be treated includes, but is not limited to Microbial keratitis, Conjunctivitis or other diseases caused by a pathogen. Pathogens include bacteria, parasites, fungi, viruses, viroids and prions.

[0056] Example 1

[0057] Lotrafilcon A contact lenses (Focus Night and Day) were placed in a spin- coater (Headway Research, lnc PWM32) and a 20 μL or 10 μl_ drops of 1 % chitosan/acetic acid solution were applied to the lenses. Next, the lenses were spin coated. The spin-coater (Headway Research, Inc. PW32) was programmed to ramp up at lOOORPM/sec for .5 seconds, then spin at 500RPM for 300 seconds and finally ramp down at 250RPM/sec for 2 seconds (See FIG. 3 and FIG. 4). After spin coating, the lenses were flash frozen in a freezer. Next the lenses were lyophilized (Freeze Zone 6 plus lyophilizer made by LabConco, Model No: 7934020). After lyophilization, the prototype lenses were analyzed and tested.

[0058] Scanning electron microscopy was used to examine the structure and location of chitosan on the lenses. Confocal microscopy was used to evaluate the dissipation of chitosan in an aqueous environment and to determine the thickness of the chitosan layer. A spectrophotometer was used to evaluate the light transmittance of the coated lenses compared to an un-coated lens. Antibacterial activity was assessed using three types of bacteria. The mechanical properties of the coated lenses were established using MTS testing. An investigation of cornea damage was conducted using anesthetized pigs' eyes. [0059] The chitosan-coated lenses were found to have a visible, white ring of chitosan in the interior of the lenses after lyophilization, as shown in FIG. 4. A Scanning

Electron Microscope (SEM) was used to examine the chitosan structure of the ring on the lyophilized lenses. In order to image the backscatter of electrons from the SEM, the sample lens was sputter coated with a gold-palladium layer 10-20 A thick. FIG. 5 shows the area in which the contact lens was imaged with the SEM.

[0060] The chitosan structure was visible by the naked eye, which allowed for easy targeting with the SEM. The microscopic chitosan structure was determined by comparing chitosan on both rigid and soft lenses. The images in FIG. 6 were all taken from the ring area of the lens. An example chitosan structure consisted of a network of holes, as seen in FIG. 6 (b-d), however a spider-web, netted structure was also observed (a).

[0061] A distinct contrast can be seen between the chitosan ring and the smooth lens surface, shown in FIG. 6 and FIG. 7 respectively. FIG. 7 (a) shows the control lens, which was not coated with chitosan, and (b) shows the edge of a coated lens, which looks similar to the uncoated lens, suggesting that the chitosan never reached the edge of the lens through spin-coating.

[0062] A confocal microscope was used to image chitosan on the lens. Chitosan fluoresces at many different wavelengths creating a saturated image; however with the addition of green fluorescein the structure can be clearly identified. The images in FIG.

8 are of lyophilized chitosan on soft lenses, exhibiting web-like structure.

[0063] To verify the presence of chitosan for at least 12 hours layer dissipation tests were conducted in an aqueous environment. Lyophilized chitosan coated lenses were soaked in saline for different periods of time, then placed on a microscope slide and imaged. FIG. 9 shows the brightness of the chitosan lens after being submerged for 0, 1 , 2, 4, 6 and 12 hours, respectively. Decreasing brightness is representative of decreasing chitosan quantity, which is to be expected as chitosan dissipates into solution. It is important to note that after 12 hours, there was still some chitosan present on the lenses, although it is difficult to observe in FIG. 9. All images in FIG. 9 were taken under the same signal amplification, which was too weak to image chitosan after

12 hours. With a higher signal amplification, it was clear that there was still some chitosan on the lenses after 12 hours, as seen in FIG. 9.

[0064] Confocal microscopy was used to measure the thickness of the chitosan layer on the lens. By taking z-plane slices of the chitosan layer, the layer was found to be -70 microns thick when soaked for 0 hours, to a minimum of ~10 microns when soaked for 12 hours as seen in FIG. 10

[0065] Similar dissipation tests were conducted for lenses that were not lyophilized but instead were air- dried. The results are shown in FIG. 11.

[0066] A comparison of FIG. 9 and FIG. 11 indicates that the chitosan did not dissipate at a faster rate off the air-dry lenses than the lyophilized lenses after 12 or 6 hours.

[0067] In order to quantify optical purity of the contact lenses before and after treatment with chitosan, % light transmittance readings over the wavelength range of

200 to 800 nm were obtained using Beckman DU7400 Spectrophotometer. However, only the visible range is necessary for comparing optical transmittance of contact lenses. Soft contact lenses were inserted directly into the cuvette containing Lens

Plus® preservative-free saline solution as shown in FIG. 12.

[0068] As seen in FIG. 13, the spectrophotometer output displays a graph of percent light transmittance versus wavelength of light. Three readings for the blank cuvette and sample lens were taken in order to ensure repeatability.

[0069] The transmittance values at 440 and 800 nm and the local minima of the transmittance curve between these two points were recorded for each lens. These characteristics are summarized in Table 1 , and were used as a reference for prototype evaluation.

Table 1 : Light Transmittance (LT%) Raw Data Summary

[0070] The light transmittance readings or the coated lens, as seen in FIG. 14, were taken as described above and compared with the untreated control lens from Table 1. Even though the readings for prototype lens appear to have higher transmittance than those for the control lens, the numerical data cannot be compared since the conditions of the experiment cannot be replicated exactly for every test. Instead, the vertical distance between the blank and lens curves should be compared. As a result, it can be observed that the control lens exhibits an approximate distance of 1.5-4.5 % LT in the active wavelength range and the prototype lens ranges from 1.5-5% LT. These results indicate that addition of the chitosan layer does not appreciably affect the light transmittance of the contact lens and thus would not obstruct the patient's vision.

[0071] In order to extract the modulus of elasticity and ultimate yield strength, the data must be converted from force and displacement to stress and strain. Two un- coated Lotrafilcon A (Focus Night & Day) lenses were used as controls and two chitosan coated lenses were used for comparison. Both control and coated lenses were re-hydrated in saline and placed in dry clamp set-up. A programmed MATLAB m-file uses the raw force, initial clamp separation, thickness of lens, and height of lens (diameter) data to output a stress-strain curve. Strain is calculated using ε = ΔL/L, where ΔL is the difference between final clamp separation and initial separation and L is initial clamp separation. Stress is calculated using σ = F/A, where F is the force data, A is the product of the lens thickness and lens diameter. The four lens (both control and coated) curves are displayed in FIG. 15. The ultimate tensile stresses which are also calculated in the m-file are tabulated in Table 2. Table 2: Mechanical Strength Testing Results for both Coated and Un-coated lenses.

[0072] Analyzing FIG. 15, it is apparent there is much variance in the curve shape and magnitude of all the lenses. There is no apparent relationship between curve and coating condition (coated or control), which suggests that the coating does not alter the mechanical properties of the lens. The abrupt decrease in stress displayed on both Control #1 and Coated #2 correspond to a fast fracture of the lens after the UTS was obtained. The slight jagged and less smooth decrease in stress on both Control #2 and Coated #1 correspond to a slow fracture. This inconsistency in fracture implies that there is no dependence on coating and must rather be an equipment variance or individual lens property.

[0073] Analyzing Table 2, it can be observed the initial lens height and separation

(width) in the MTS clamps are relatively consistent. The Ultimate Tensile Stresses were calculated from data; however the initial height and width of the lens were experimentally measured. The UTS values of the coated lenses are within the range of the UTS values of the control, uncoated lenses. From this table and the curve results, it can be concluded that the chitosan coating has no significant effect on the original mechanical properties of the lens.

[0074] Antibacterial tests for Staphylococcus, gram-positive bacteria, exhibited a marked difference between the positive control lens and the prototype lens. While the control plate was covered with hundreds of bacterial colonies, all three of the chitosan prototype lens plates had much fewer colonies (FIG. 16). Additional tests with 10 μl_ prototype did not show an appreciable difference in growth from 20 μl_ samples (FIG. 17).

[0075] Additional antibacterial tests were also conducted with Proteus mirabilis, gram-negative bacteria. The tests show that the prototype is effective in inhibiting these bacteria (FIG. 18). The contact lens prototype may be more effective with gram-positive and gram-negative bacteria. Tests were only done with a control plate and a 20 μl_ plate.

Claims

ClaimsWhat is claimed is:

1. A method of treating an eye infection comprising contacting the eye with an ophthalmic lens comprising chitosan.

2. The method of claim 1 , wherein the infection is caused by one or more pathogens.

3. The method of claim 1 , wherein the chitosan comprises one or more chitosan derivatives.

4. The method of claim 1 , wherein the one or more chitosan derivatives comprises chitosan-arginine or chitosan-guanidine.

5. The method of claim 1 , wherein at least a portion of a surface of the ophthalmic lens is coated with a chitosan layer.

6. The method of claim 1 , wherein the ophthalmic lens is a contact lens.

7. The method of claim 2, wherein the pathogen is a species of Streptococcus, Staphylococcus, Pseudomonas, Enterobacteriaceae, Serratia, or Acinetobacter.

8. The method of claim 2, wherein the pathogen is a species of Aspergillus, Alternaria and Phialophora.

9. The method of claim 1 , wherein the eye infection is Microbial keratitis.

10.An ophthalmic lens comprising chitosan for treating eye infections, wherein the ophthalmic lens is capable of substantially inactivating one or more pathogens.

11. The ophthalmic lens of claim 10, wherein the chitosan comprises one or more chitosan derivatives.

12. The ophthalmic lens of claim 11 , wherein the one or more chitosan derivatives comprises chitosan-arginine or chitosan-guanidine.

13. The ophthalmic lens of claim 10, wherein at least a portion of a surface of the ophthalmic lens is coated with a chitosan layer.

14. The ophthalmic lens of claim 13, wherein the chitosan layer comprises a donut shaped pattern such that a center region on the surface of the ophthalmic lens remains uncoated.

15. The ophthalmic lens of claim 10, wherein the ophthalmic lens is a contact lens.

16. The ophthalmic lens of claim 10, wherein the pathogen is a species of

Streptococcus, Staphylococcus, Pseudomonas, Enterobactehaceae, Serratia, or Acinetobacter.

17. The ophthalmic lens of claim 10, wherein the pathogen is a species of Aspergillus, Alternaha and Phialophora.

18. The ophthalmic lens of claim 10, wherein the eye infection is Microbial keratitis.

19.A method of making an ophthalmic lens capable of substantially inactivating one or more pathogens, comprising forming a chitosan layer on at least a portion of a surface of the ophthalmic lens.

20. The method of claim 19, wherein the chitosan layer comprises a chitosan derivative.

21. The method of claim 19, wherein the chitosan derivative is chitosan-arginine or chitosan-guanidine.

22. The method of claim 19, wherein the ophthalmic lens is a contact lens.

23. The method of claim 19, wherein said forming a chitosan layer on at least a portion of a surface of the ophthalmic lens comprises applying a chitosan solution to at least a portion of a surface of the ophthalmic lens.

24. The method of claim 23, wherein said applying a chitosan solution to at least a portion of a surface of the ophthalmic lens comprises spin coating.

25. The method of claim 23, wherein the chitosan solution comprises a concentration of chitosan in the range of 0.001 % to 6% by weight.

26. The method of claim 19, wherein the chitosan layer comprises a donut shaped pattern such that a center region on the surface of the ophthalmic lens remains u n coated.

27. The method of claim 19, wherein said forming a chitosan layer on at least a portion of a surface of the ophthalmic lens includes lyophilizing the ophthalmic lens.

28. The method of claim 19, wherein said forming a chitosan layer on at least a portion of a surface of the ophthalmic lens includes polymerizing the chitosan layer in situ.

29. The method of claim 19, wherein the pathogen is a species of Streptococcus, Staphylococcus, Pseudomonas, Enterobacteriaceae, Serratia, or Acinetobacter.

30. The method of claim 19, wherein the pathogen is a species of Aspergillus, Alternaria and Phialophora.