Color vision deficiency (CVD) is an ocular congenital disorder that affects 8% of males and 0.5% of females. The most prevalent form of color vision deficiency (color blindness) affects protans and deutans and is more commonly known as “red–green color blindness”. Since there is no cure for this disorder, CVD patients opt for wearables that aid in enhancing their color perception. The most common wearable used by CVD patients is a form of tinted glass/lens. Those glasses filter out the problematic wavelengths (540–580 nm) for the red–green CVD patients using organic dyes. However, few studies have addressed the fabrication of contact lenses for color vision deficiency, and several problems related to their effectiveness and toxicity were reported. In this study, gold nanoparticles are integrated into contact lens material, thus forming nanocomposite contact lenses targeted for red–green CVD application. Three distinct sets of nanoparticles were characterized and incorporated with the hydrogel material of the lenses (pHEMA), and their resulting optical and material properties were assessed. The transmission spectra of the developed nanocomposite lenses were analogous to those of the commercial CVD wearables, and their water retention and wettability capabilities were superior to those in some of the commercially available contact lenses used for cosmetic/vision correction purposes. Hence, this work demonstrates the potential of gold nanocomposite lenses in CVD management and, more generally, color filtering applications.

Although the manufacturing processes of contact lenses are well established, the use of additive manufacturing for their fabrication opens many new possibilities to explore. The current study demonstrates the fabrication of personalized smart contract lenses utilizing additive manufacturing. The study includes 3-dimensional (3D) modeling of contact lenses with the assistance of a computer aided designing tool based on standard commercial contact lens dimension, followed by the selection of the suitable materials and 3D printing of contact lenses. The 3D printing parameters were optimized to achieve the desired lens geometries, and a post processing treatment was performed to achieve a smooth surface finish. The study also presents functionalized contact lenses with built-in sensing abilities by utilizing microchannels at the contact lens edges. Tinted contact lenses were printed and nanopatterns were textured onto the contact lens surfaces through holographic laser ablation. 3D printed contact lenses have advantages over conventional contact lenses, offering customized ophthalmic devices and the capability to integrate with optical sensors for diagnostics.

Color vision deficiency (CVD) or color blindness is an ocular disorder that hinders the patients from distinguishing shades of certain colors. Color blind patients are often not considered for critical occupations (e.g., military, police) and cannot differentiate colors in public places or media (i.e., watching TV). The most common form of color blindness is red‐green, which is a result of either a missing or defective red or green photoreceptor cone. Since no cure for this disorder exists, sufferers opt for methods to enhance their color perception. The products and methods that have been developed to aid CVD patients are discussed. These technologies include contemporary work on gene therapy, tinted glasses, lenses, optoelectronic glasses, and advanced features developed on smartphones and computers. Among these wearables, tinted glasses, developed by companies such as Enchroma, are the most widely used by CVD patients.

No abstract

No abstract

Color distinction is vital in daily life practices as it aids in identifying and distinguishing different objects along with emphasizing the visual perceived information. Yet, color vision deficiency (CVD) or colorblindness is a very common congenital disorder that limits the ability of the patient to distinguish between shades of certain colors. [1] CVD patients experience difficulties in distinguishing colors in their daily lives, such as traffic lights, LED lights on some devices, ripened or raw vegetables and fruits, and colors of sports' jerseys along with an overall depression stemming from the idea that they cannot enjoy a variety of aesthetical experiences (Figure 1). Moreover, according to prior studies, approximately 7%-8% of male population and 0.4%-0.5% of female population are suffering from congenital CVD. [2,3] Human eyes perceive colors with the help of photoreceptor cells also known as cone cells present in the eye's retina. [4,5] The cone cells are categorized based on the wavelengths they are sensitive toward, that is, short (S), medium (M), and large (L); those are also commonly termed as blue, green, and red cone cells, respectively (Figure 1E-H). Moreover, normal color vision is trichromatic, in which all three cones are present in the eye and are well functioning; however, colorblind patients usually suffer from a missing or faulty cone cell. According to the latter, CVD can be divided as follows: protanomaly (faulty L-cone) or protanopia (missing L-cone), deuteranomaly (faulty M-cone) or deuteranopia (missing M-cone), and tritanomaly (faulty S-cone) or tritanopia (missing S-cone). Further, protans and deutans are commonly categorized as red-green CVD patients whereas tritans are usually referred to as blue-yellow CVD patients. [6] Among these types of CVDs, red-green is the most common. [7,8] Furthermore, there are several methods for determining the CVD type and its severity. One of these approaches is the use of pseudoisochromatic testing plates, which seem to be of a single color to people suffering from CVD. The Ishihara test is the most popular and is commonly available among the optometrists. [9,10] There are many variations of the test, each with a different number of tests plate, but the 38-plate version is the most common. The Ishihara test can only detect red-green colorblindness and cannot classify a patient as a protan, deutan, or tritan. [11] Other tests, such as Hardy-Rand-Rittler (HRR), Fransworth-Munsell (FM) 100 Hue, and Fransworth D-15, can be used to get such detailed information. [12,13] Another testing method involves the usage of anomaloscopes, which utilize control knobs that reflect the form and severity of the CVD. [14] Anomaloscopes use control knobs to align two images with their color brightness. They are the most complex to use, even though they offer a reliable classification of all CVD conditions.

Color blindness or color vision deficiency (CVD) affects around 4.5% of the population in Europe. There have been several attempts to assist color‐blind individuals using color filter glasses. Here, contact lenses are developed to assist individuals suffering from color blindness. Two dyes (Atto 488 and 565) that provide the desired absorption wavelength ranges are selected to be immobilized in soft contact lenses. The chosen dyes have absorption bands in wavelength ranges of 480–500 and 550–580 nm. Both dyes are individually immobilized in contact lenses, and over 95% of the light in the undesired ranges are blocked. The dyes do not diffuse out from lenses in artificial tears and contact lens storage solution. Performances of the developed contact lenses are compared to commercial color‐blind glasses. The contact lenses are tested in color vision deficient patients using Ishihara test. Participants indicate enhancement in the visibility of the colors and their contrast in a color rich environment. The proposed contact lenses show enhanced results as compared to commercial color‐blind glasses in indoors and achieved similar outcomes outdoors.

Advances in multifunctional materials and technologies have allowed contact lenses to serve as wearable devices for continuous monitoring of physiological parameters and delivering drugs for ocular diseases. Since the tear fluids comprise a library of biomarkers, direct measurement of different parameters such as concentration of glucose, urea, proteins, nitrite, and chloride ions, intraocular pressure (IOP), corneal temperature, and pH can be carried out non-invasively using contact lens sensors. Microfluidic contact lens sensor based colorimetric sensing and liquid control mechanisms enable the wearers to perform self-examinations at home using smartphones. Furthermore, drug-laden contact lenses have emerged as delivery platforms using a low dosage of drugs with extended residence time and increased ocular bioavailability. This review provides an overview of contact lenses for ocular diagnostics and drug delivery applications. The designs, working principles, and sensing mechanisms of sensors and drug delivery systems are reviewed. The potential applications of contact lenses in point-of-care diagnostics and personalized medicine, along with the significance of integrating multiplexed sensing units together with drug delivery systems, have also been discussed.