Bilim adamları, kontakt lens kaynaklı kuru gözü önlemek için özel olarak tasarlanmış bir kontakt lens prototipine sahiptir. Kredi: Terasaki Biyomedikal İnovasyon Enstitüsü
Terasaki Biyomedikal İnovasyon Enstitüsü’nden (TIBI) bir ekip, kontakt lens kaynaklı kuru gözle (CLIDE) mücadele etmeyi amaçlayan çığır açan bir kontakt lens prototipi yarattı. Bu yenilikçi lens tasarımı, normal göz kırpma yoluyla gözyaşı akışını teşvik ederek CLIDE’ı hafifletmeye yardımcı olur. Bu gelişme, CLIDE’den muzdarip milyonlarca kontakt lens kullanıcısının karşılaştığı rahatsızlığı, görme sorunlarını ve iltihaplanma risklerini azaltma potansiyeline sahiptir.
Dünya çapında kontakt lens kullanan 140 milyon kişiden %30 ila %50’si CLIDE deneyimini yaşıyor. CLIDE, kontakt lensin dış yüzeyinden iç yüzeye yetersiz gözyaşı akışı nedeniyle oluşur, bu da aşırı gözyaşı buharlaşmasına ve buna bağlı CLIDE semptomlarına neden olur.
Bu durum için mevcut tedaviler arasında yeniden ıslatma damlaları, jeller veya kayganlaştırıcılar, daha sık lens değişimi veya lens materyalindeki değişiklikler yer alır. Göz kapağı masajı ve sıcak kompres gibi göz kapağı tedavileri de vardır. Daha ciddi vakalarda, gözyaşı bezlerinin fiziksel olarak uyarılmasının yanı sıra drenajı engellemek için gözyaşı kanallarına yerleştirilen punktum tıkaçları kullanılabilir. Etkinlik bu tedaviler arasında farklılık gösterir, ancak vücutta potansiyel olarak zararlı ilaç birikimleri olabilir ve kullanıcı dostu olmayan yöntemler hasta uyumsuzluğuna katkıda bulunur.
Kuru göz sendromunun tedavisinde kontakt lens kullanımına yönelik daha önceki girişimler de olmuştur.[{” attribute=””>graphene-coated lenses designed to minimize moisture loss and self-moisturizing lenses stimulated with metallic electrodes. But these methods are costly and impractical and may compromise patient safety and comfort.
The TIBI team’s approach uses a contact lens design that incorporates microchannels to facilitate tear flow movement and flow so that dry eye can be avoided. This flow can be achieved by pressure applied by normal eye blinking so that no external devices are needed.
In fabricating their contact lens prototype, the team utilized a time-saving method – their lens mold was made from a silicone polymer mixture; this allowed for easy removal of the lens cast on it by gently bending the mold. Previous methods necessitated a twelve-hour soak in hot water to remove the lens. The approach resulted in high-quality, smooth microchannels, as well as lenses that could be thirty times thinner than previous lenses. A custom device was used to fabricate reservoirs at the ends of each microchannel for the inflow and outflow of liquids.
Innovative techniques were also utilized when encapsulating the microchannels in a sandwich-like assembly under a capping lens layer. Initially, the preparation of the two lens surfaces for stronger bonding dehydrated the lenses, causing them to curl. This problem was solved by affixing the two lenses to holders using water-soluble glue. This served not only to enable a more uniform bonding of the lenses but protected them from damage as well.
After rigorously testing their encapsulated microchannel lenses for stability and leakage, the lenses were subjected to a series of experiments using a device that the team designed to simulate a blinking eyelid. This device was integrated with the lens prototype to create artificial eyelid pressure on the lens to stimulate tear flow.
After various experiments, a configuration that proved effective was microchannels with square cross-sections arrayed in a novel circular pattern on the lens surface; this was compatible with the function and curvature of the lens and allowed for optimum liquid flow.
The team demonstrated a proof-of-concept validation of their lens’ ability to guide tear flow originating from the lens surface to the underside of the lens to combat dry eye syndrome. The team quantified these flows and established that the flows were driven by low-pressure levels like those from normal eye blinking. Further experiments could be devised to test these lenses on animal models and in patients.
“The inventive methods that our team has employed bring a potential solution for millions of people,” said Ali Khademhosseini, TIBI’s Director and CEO. “It is the hope that we may extend our efforts to bring this solution to fruition.”
Reference: “A Microfluidic Contact Lens to Address Contact Lens-Induced Dry Eye” by Yangzhi Zhu, Rohollah Nasiri, Elham Davoodi, Shiming Zhang, Sourav Saha, Matthew Linn, Lu Jiang, Reihaneh Haghniaz, Martin C. Hartel, Vadim Jucaud, Mehmet R. Dokmeci, Anna Herland, Ehsan Toyserkani and Ali Khademhosseini, 23 December 2022, Small.
DOI: 10.1002/smll.202207017
The study was funded by Cooper Vision, Inc.