Pigmented contact lenses for managing ocular disorders

Novel Drug Delivery Systems for the Management of Fungal Keratitis

Fungal keratitis (FK) is a dangerous corneal infection that is common in tropical and subtropical areas. Its incidence is extremely high, and ocular trauma and contact lenses can lead to FK, but its common treatment such as using topical antifungal eye drop instillation is often less effective because of several drawbacks of the drugs typically used, including limited ocular penetration, high frequency of dosing, poor biocompatibility, and the potential for severe drug reactions. Therefore, the development of novel drug delivery devices for the treatment of FK is urgent. The urgent need for novel drug delivery devices to treat FK has led to the development of several techniques, including nanoparticles (NPs), in situ forming hydrogels, contact lenses, and microneedles (MNs). However, it is important to note that the main mechanisms differ between these techniques. NPs can transport large amounts of drugs and be taken up by cells owing to their large surface area and small size. In situ forming hydrogels can significantly extend the residence time of drugs because of their strong adhesive properties. Contact lenses, with their comfortable shape and drug-carrying capacity, can also act as drug delivery devices. MNs can create channels in the cornea, bypassing its barrier and enhancing drug bioavailability. This article will go over novel medication delivery techniques for treating FK and make a conclusion about their advantages and limitations in anticipation to serve the best option for the individual therapy of FK.

3D Printing of Multimaterial Contact Lenses

3D printing of multimaterial objects is an emerging field with promising applications. The layer-by-layer material addition technique used in 3D printing enables incorporation of distinct functionalized materials into the specialized devices. However, very few studies have been performed on the usage of multimaterial 3D printing for printable photonic and wearable devices. Here, we employ vat photopolymerization-based 3D printing to produce multimaterial contact lenses, offering enhanced multiband optical filtration, which can be valuable for tackling ocular conditions such as color blindness. A combination of hydroxyethyl methacrylate (HEMA) and polyethylene glycol diacrylate (PEGDA) was used as the base hydrogel for 3D printing. Atto565 and Atto488 dyes were added to the hydrogel for wavelength filtering, each dye suitable for a different type of color blindness. Multimaterial disks and contact lenses, with separate sections containing distinct dyes, were 3D-printed, and their optical properties were studied. The characteristics of multimaterial printing were analyzed, focusing on the formation of a uniform multimaterial interface. In addition, a novel technique was developed for printing multiple dyed materials in complex lateral geometrical patterns, by employing suitable variations in CAD models and the UV curing time. It was observed that the multimaterial printing process does not negatively affect the optical properties of the contact lenses. The printed multimaterial contact lenses offered a combined multi-band color blindness correction due to the two dyes used. The resulting optical spectrum was a close match to the commercially available color blindness correction glasses.

Use of Soft Contact Lens for Esthetic and Functional Rehabilitation

OBJECTIVE

To report the outcomes and complications of colored soft contact lenses (SCLs) to improve esthetic or eye function in visually impaired (VI) or blind patients.

METHODS

This retrospective study enrolled consecutive patients with unilateral or bilateral VI or blindness who had received colored SCLs to improve appearance or ocular function. Data were collected on demographics, complaints, complete ophthalmological examinations, types of SCL, follow-ups, and complications.

RESULTS

The study sample was comprised of 109 patients (ages 4-80 years). Eighty-six patients (78.89%) had unilateral blindness, and 14 patients (12.84%) had functional disorder. Most of the patients presenting for improved esthetic had anterior segment pathology (74/67.88%), mainly secondary to trauma (55/50.5%) resulting in leukoma (73/66.97%). Patients with functional VI (19/17.43%) received filtered SCLs for color blindness (7/6.42%), diplopia (7/6.42%), or photophobia (5/4.58%). No serious complications were observed in any cases, and 94.49% of patients were satisfied with the SCLs.

CONCLUSION

Colored SCLs can cover ocular surface imperfections in VI or blind eyes of patients who are seeking better cosmesis or improvement functional VI. Soft contact lenses with only one filter can cover imperfections of the ocular surface and improve vision in functional VI. Appropriate follow-up of these patients can reduce complication rates, resulting in good cosmesis and patient satisfaction with a positive impact on the lives of patients suffering from functional VI or blindness.

Resveratrol-Loaded Hydrogel Contact Lenses with Antioxidant and Antibiofilm Performance

Contact lenses (CLs) are prone to biofilm formation, which may cause severe ocular infections. Since the use of antibiotics is associated with resistance concerns, here, two alternative strategies were evaluated to endow CLs with antibiofilm features: copolymerization with the antifouling monomer 2-methacryloyloxyethyl phosphorylcholine (MPC) and loading of the antioxidant resveratrol with known antibacterial activity. MPC has, so far, been used to increase water retention on the CL surface (Proclear^® 1 day CLs). Both poly(hydroxyethyl methacrylate) (HEMA) and silicone hydrogels were prepared with MPC covering a wide range of concentrations (from 0 to 101 mM). All hydrogels showed physical properties adequate for CLs and successfully passed the hen’s egg-chorioallantoic membrane (HET-CAM) test. Silicone hydrogels had stronger affinity for resveratrol, with higher loading and a slower release rate. Ex vivo cornea and sclera permeability tests revealed that resveratrol released from the hydrogels readily accumulated in both tissues but did not cross through. The antibiofilm tests against Pseudomonas aeruginosa and Staphylococcus aureus evidenced that, in general, resveratrol decreased biofilm formation, which correlated with its concentration-dependent antibacterial capability. Preferential adsorption of lysozyme, compared to albumin, might also contribute to the antimicrobial activity. In addition, importantly, the loading of resveratrol in the hydrogels preserved the antioxidant activity, even against photodegradation. Overall, the designed hydrogels can host therapeutically relevant amounts of resveratrol to be sustainedly released on the eye, providing antibiofilm and antioxidant performance.