the present inventions provide a scleral lens and a drug which is retained in the expanded pre - corneal tear film defined as the area between the scleral lens and the cornea . in another embodiment , the present inventions provide a scleral lens and stem cells in the aqueous environment defined as the area between the scleral lens and the cornea . the scleral lens is made of a rigid gas permeable material . additionally , the scleral lens may have channels which are disposed on the inside surface of the scleral lens and extend generally radially from the inside of the scleral contact portion ( haptic ) of the scleral lens and the outside rim of the scleral lens . the present inventions also provide a method of increasing the bioavailability of a drug delivered to the surface of the eye using a scleral lens , whereby a solution of a drug is added to the expanded pre - corneal tear film defined as the area between the scleral lens and the cornea . in another embodiment , the present inventions provide a method of retaining stem cells at the surface of the eye in an aqueous environment using a scleral lens . a scleral lens is a device that can be used to address corneal surface conditions . as shown in fig1 - 4 , a scleral lens 10 , which is about the size of a quarter , rests on the white sclera 12 of an eye 14 . lens 10 has a dome - shape that defines a fluid compartment space 16 over a cornea 18 that can be filled with fluid , such as artificial tears . as illustrated by the contact length l in fig2 , contact with the eye is limited to the sclera and the lens does not contact cornea 18 . alternatively , the scleral lens contacts the sclera and the periphery of the cornea . this contact location for the scleral lens is different from conventional contact lenses which rest on the cornea . by covering ( without contacting ) the irregular surface of the damaged cornea , this lens device can improve vision in eyes with distorted corneas , and even ones with extreme distortion . the optic portion 34 of the scleral lens may be formed to correct the vision of the patient . such a scleral lens is an optically corrective lens . alternatively , the optic portion 34 may not help to correct the vision of the patient . the fluid compartment becomes a “ liquid bandage ,” which is referred to as an expanded pre - corneal tear film or as a supplemented pre - corneal tear film , defined by lens 10 that protects the cornea from dryness and from mechanical trauma from the lids with each blink . the expanded pre - corneal tear film is a therapeutic environment that supports healing and that can reduce or even virtually eliminate pain and photosensitivity . this expanded pre - corneal tear film has helped , and even been responsible for the extraordinary healing experienced by , patients who have used the scleral lens . a scleral lens can be used to treat a number of conditions , including dry eyes and keratoconus . a scleral lens can be used as a drug delivery system by providing a drug in the expanded pre - corneal tear film defined by the inner surface of the scleral lens and the surface of the cornea . the drug is thereby retained in the expanded pre - corneal tear film between the lens and the eye . the present inventions provide a system for delivering antibiotic agents , antiviral agents , antifungal agents , antiparasitic agents , corticosteroids , non - steroidal anti - inflammatory drugs , mydriatics , biologics , drugs that modify neovascularization , tissue engineering components , drugs that increase aqueous outflow , drugs that reduce aqueous secretion , antihistamines , mast cell stabilizers , secretagogues , tear supplements , anti - metabolites , and immunomodulators to the eye . the present inventions also provide a method for treating disease processes of the eye , including bacterial infection , viral infection , fungal infection , parasitic infection , inflammation , neovascularization , ocular surface disease , glaucoma , allergy , dry eye , dysplasia , and neoplasm . corneal neovascularization ( i . e ., formation of new blood vessels ) is a pathologic process that occurs as part of healing after infection , trauma , or corneal inflammatory processes . although neovascularization is part of the scar that prevents perforation and loss of the eye , its presence puts the eye at risk of rejection should cornea transplantation be required . neovascularization can cause calcium and cholesterol deposits and often has associated fibrous tissue , all of which can preclude fine vision . there is little that can be done to treat the eye once neovascularization begins , other than applying a topical steroid ( which acts non - specifically ) and treating the underlying disease . some drugs that block neovascularization interact with vascular endothelial growth factor ( vegf ) or its receptors ( vegfr ). non - limiting examples of vegf include vegf - a , vegf - b , vegf - c , and vegf - d . non - limiting examples of vegfr include vegfr - 1 , vegfr - 2 , and vegfr - 3 . non - limiting examples of drugs that block neovascularization by interacting with vegf or vegfr include avastin ® ( bevacizumab ), macugen ® ( pegaptanib sodium injection ), and lucentis ® ( ranibizumab injection ). avastin ® ( bevacizumab ), a recombinant humanized monoclonal igg1 antibody that binds to and inhibits the biologic activity of vegf , has been approved for the systemic treatment of colon cancer . avastin ® is also used off - label as an injection into the eye for retinal neovascularization associated with age related macular degeneration ( amd ). macugen ® ( pegaptanib sodium injection ), an anti - vegf inhibitor , and lucentis ® ( ranibizumab injection ), an antibody fragment designed to bind and inhibit vegf - a , are approved for injection into the eye for amd . as illustrated in fig4 , a portion of a scleral lens 30 includes both a scleral contact surface 32 and a vaulting lens portion 34 . the vaulting lens portion is disposed above the cornea when the scleral lens is applied to an eye . the scleral surface of the eye contacts the lens at the scleral contact surface 32 . in an alternate embodiment , the scleral lens may rest on the sclera and the periphery of the cornea . as illustrated in fig2 , liquid 16 is interposed between the inner surface of the lens portion 10 and the surface of the cornea 18 . drug is contained in this liquid , thus keeping the drug in contact with the surface of the cornea . in another embodiment , the liquid contains stem cells and retains them at the surface of the cornea in an aqueous environment . drugs suitable for use with the present invention include antibiotic agents , antiviral agents , antifungal agents , antiparasitic agents , corticosteroids , non - steroidal anti - inflammatory drugs , mydriatics , biologics , drugs that modify neovascularization , tissue engineering components , drugs that increase aqueous outflow , drugs that reduce aqueous secretion , antihistamines , mast cell stabilizers , secretagogues , tear supplements , and anti - metabolites . this drug delivery system can be used to treat disease processes of the eye , including bacterial infection , viral infection , fungal infection , parasitic infection , inflammation , neovascularization , ocular surface disease , glaucoma , allergy , dry eye , dysplasia , and neoplasm . in another embodiment , the method of the present invention is performed by adding a solution containing stem cells to the expanded pre - corneal tear film . non - limiting examples of diseases that may be treated using the method of the present invention with stem cells include chemical burns , stevens - johnson syndrome , aniridia , and ocular cicatricial pemphigoid . non - limiting examples of drugs suitable for use with the present inventions include antibiotic agents , antiviral agents , antifungal agents , antiparasitic agents , corticosteroids , non - steroidal anti - inflammatory drugs , mydriatics , biologics , drugs that modify neovascularization , tissue engineering components , drugs that increase aqueous outflow , drugs that reduce aqueous secretion , antihistamines , mast cell stabilizers , secretagogues , tear supplements , anti - metabolites , and immunomodulators . the term “ antibiotic ” as used herein is defined as a drug that kills or prevents the growth of bacteria . non - limiting examples of antibiotics useful in the present inventions include polytrim ® ( trimethoprim sulfate / polymyxin b sulfate ), zymar ® ( gatifloxacin ), and vigamox ® ( moxifloxacin hydrochloride ). the term “ antiviral ” as used herein is defined as a drug that treats viral infections . a non - limiting example of an antiviral useful in the present inventions is viroptic ® ( trifluridine ). the term “ antifungal ” as used herein is defined as a drug that prevents the growth of fungi . a non - limiting example of an antifungal useful in the present inventions is natamycin ( pimaricin ). the term “ antiparasitic ” as used herein is defined as a drug that treats infection by parasites . non - limiting examples of antiparasitics useful in the present inventions are brolene ( propamidine isethionate ), hibiclens ® ( chlorhexidene gluconate ), and periostat ® ( doxycycline hyclate ). the term “ corticosteroid ” as used herein is defined as a class of steroid hormones that are useful for regulating physiologic systems such as stress response , immune response and regulation of inflammation , carbohydrate metabolism , protein catabolism , blood electrolyte levels , and behavior . non - limiting examples of corticosteroids useful in the present inventions include pred forte ® ( prednisolone acetate ), lotemax ® ( loteprednol etabonate ), and fml forte ® ( fluorometholone ) the term “ non - steroidal anti - inflammatories ” as used herein is defined as drugs with analgesic , antipyretic and anti - inflammatory effects that are non - steroidal . non - limiting examples of non - steroidal anti - inflammatories useful in the present inventions include acular ® ( ketorolac tromethamine ) and voltaren ® ( diclofenac ). the term “ mydriatic ” as used herein is defined as a drug that induces dilation of the pupil . a non - limiting example of a mydriatic useful in the present inventions is isopto ® hyoscine ( scopolamine ). the term “ biologic ” as used herein is defined as a product that may be composed of sugars , proteins , or nucleic acids or complex combinations of these substances , or may be living entities such as cells and tissues . non - limiting examples of biologics useful in the present inventions include avastin ® ( bevacizumab ), macugen ® ( pegaptanib ), lucentis ® ( ranibizumab ), autologous serum , fetal cord serum , and amniotic membrane extracts . the term “ drug that modifies neovascularization ” as used herein is defined as a drug that modifies the formation of new blood vessels . non - limiting examples of drugs that modify neovascularization useful in the present inventions include pred forte ® ( prednisolone acetate ), avastin ® ( bevacizumab ), macugen ® ( pegaptanib ), and lucentis ® ( ranibizumab ). the term “ tissue engineering component ” as used herein is defined as a material used to repair or replace portions of tissues or whole tissues . non - limiting examples of tissue engineering components useful in the present inventions include limbal stem cells , autologous stem cells , and allogeneic stem cells . the term “ drug that increases aqueous outflow ” as used herein is defined as a drug that increases pressure in the eye by increasing the production of aqueous . non - limiting examples of drugs that increase aqueous outflow useful in the present inventions include pilocarpine , xalatan ® ( latanoprost ), timoptic ® ( timolol ), and alphagan ® ( brimonidine ). the term “ drug that reduces aqueous secretion ” as used herein is defined as a drug that decreases pressure in the eye by reducing the production of aqueous . non - limiting examples of drugs that reduce aqueous outflow useful in the present inventions include trusopt ® ( dorzolamide ), azopt ® ( brinzolamide ), timoptic ® ( timolol ), and alphagan ® ( brimonidine ). the term “ antihistamine ” as used herein is defined as a drug that reduces or that eliminates the effects of histamine . non - limiting examples of antihistamines useful in the present inventions include patanol ® ( olopatadine ), elestat ® ( epinastine ), and zaditor ® ( ketotifen fumarate ). the term “ mast cell stabilizer ” as used herein is defined as a cromone medication that prevents or controls allergic disorders by preventing the release of histamine . non - limiting examples of mast cell stabilizers useful in the present inventions include alomide ® ( lodoxamide ), patanol ® ( olopatadine ), and elestat ® ( epinastine ). the term “ secretagogue ” as used herein is defined as a substance that causes other substances , such as tears , to be secreted . a non - limiting example of a secretagogue useful in the present inventions is prolacria ® ( diquafosol tetrasodium ). the term “ tear supplement ” as used herein is defined as a fluid used to increase wetness of the eye . non - limiting examples of tear supplements useful in the present inventions include refresh dry eye therapy ®, refresh tears ®, genteal ®, theratears ®, and biontears ®. the term “ anti - metabolite ” as used herein is defined as a structural analog of a naturally occurring compound , and that interferes with the production of nucleic acids . non - limiting examples of anti - metabolites useful in the present inventions include mitomycin c and 5 - fluorouracil . the term “ immunomodulator ” as used herein is defined as an agent that specifically or nonspecifically augments or diminishes immune responses . a non - limiting example of a immunomodulator useful in the present inventions is restasis ® ( cyclosporine ). avastin ® is not believed to effectively treat the cornea because the molecule is large and is therefore poorly absorbed into the cornea . a recent report using avastin ®, off - label , topically , for the treatment of corneal neovascularization rebuts this perception ( terry kim , m . d ., cornea society november 2006 , in press arch . ophthalmology april 2007 ). this study required a high concentration of the preservative bak in the avastin ® delivery vehicle to aid absorption of the drug . however , bak can be toxic to the corneal epithelium . therapeutic effect was reported after a solution of 1 % avastin ® and 0 . 01 % bak was used , one drop , four times per day for at least thirty days . this study using avastin ® off - label , topically , to treat corneal neovascularization was repeated using the scleral lens drug delivery system . one drop of 1 % avastin ® was added to the expanded pre - corneal tear film of artificial tears in a scleral lens twice per day , and achieved a therapeutic effect by thirty days with continued benefit over the subsequent sixty days . this therapeutic effect was achieved without bak . instead , the expanded pre - corneal tear film of the scleral lens drug delivery system provided adequate bioavailability of the drug without exposing the cornea to bak . fig5 is a composite of clinical photos demonstrating regression of corneal neovascularization using the scleral lens drug delivery system for avastin ®.