Post Ocular Surgery

Cataract surgery has become a very common procedure with about 10 million cataract operations each year in the world101 with a significant increase expected due to aging of the population. The surgery can result in significant inflammation, which if left untreated, could cause complications such as cystoid macular oedema, increased intraocular pressure, posterior capsular opacification, chronic uveitis, fibrin formation102. Post-surgical management requires instillation of eye drops to deliver antibiotics, steroids and NSAID but this approach has many problems. The regimen of eye drops for post cataract patients includes steroids about 3-4 times daily for 4-weeks, antibiotics about 4 times daily for 2-weeks and NSAIDs 1 times daily for 3-4 weeks. In a study with 30 patients after cataract (n = 24) and glaucoma filtration surgery (n = 6), the mean dose compliance was 50.2%, with below 25% compliance in approximately one out of five patients.5 In fact, in almost 93% cases, patents use incorrect technique to administer the eyedrops6. The lack of proper administration could cause additional problems such as corneal and conjunctival abrasions (68% of elderly study patients)7 and potential for wound gap and efflux of fluid into the eye following pressure on the eye8, which may result in an increased the risk of endophthalmitis from the eye drop treatment9.

These deficiencies have driven research in developing intracameral devices that can be placed in the anterior chamber after surgery for sustained release of dexamethasone. The FDA has approved DEXYCUTM which is an emulsion formulation that provides sustained release of dexamethasone for 21 days18,19. Clinical studies show safety, efficacy and significant patient acceptance with 68.7% in the treatment group agreeing that not using eyedrops was very convenient20. DEXTENZA® is a dexamethasone releasing puncta plug that is another commercialized device for delivery of the drug after cataract surgery6. While DEXYCU® and DEXTENZA® are improvements over eye drops, neither deliver all drugs and so patients may still require instillation of antibiotic eye drops to minimize the possibility of infections. We will solve this problem by designing contact lenses that can deliver all three drugs at controlled rates for extended durations with high bioavailability making this significantly superior to the drop-based therapy as well as other commercial devices. We note that while bandage contact lenses are not used commonly after cataract surgery, there are no contraindications and in fact multiple studies have suggested that bandage contact lenses can be safely used after cataract surgery21–23.

Freya has developed a sustained release contact lens that can replace eye drop instillations after cataract surgery. The lens releases antibiotic moxifloxacin, steroid dexamethasone and NSAID ketorolac.

Other Applications

Photo refractive keratectomy (PRK) involves removal of the corneal epithelium and reshaping the anterior stroma. PRK patients are fitted with a bandage contact lens (BCL) to protect the abraded cornea from the shear stress exerted by the blink and/or rubbing of the eyes. Bandage contact lenses are believed to possibly improve corneal healing as well. Post PRK, patients must instill multiple eye-drops containing steroids and broad-spectrum antibiotics, and in some cases additional drugs. Most of these must be applied multiple times each day, which could result in poor compliance, especially remembering that patients must wait at least 5 minutes between eye drop instillations. The problem of low bioavailability is likely exacerbated during post-PRK eye drop-based therapy due to the presence of the bandage contact lens. Bandage contact lenses are, however, very important to the healing process and, in fact, achieving longer wear durations of about 4 days after PRK could lead to better outcomes. The lenses developed by Glint will be very valuable post-PRK to combine the healing benefits of the contact lens with simultaneous release of multiple drugs that will eliminate the need for eye drops, while improving the drug bioavailability to the target.