Ocular Research

Human ocular research is the study of the eye and its surrounding structures in order to better understand eye diseases and develop new treatments. The eye is a highly complex organ, and researchers use a variety of techniques to examine different aspects of eye function. For example, eye movements can be monitored to study how the brain processes visual information. Electric signals from the eye can also be measured to understand how visual information is transmitted from the eye to the brain. In addition, new imaging technologies are being used to create detailed pictures of the eye, which can help researchers to identify early signs of disease. By continuing to advance our understanding of the eye, human ocular research is playing an important role in the prevention and treatment of eye diseases.

Fig.1 Structure of human eye. (Cholkar, et al., 2012)

Human Ocular Diseases and Related Membrane Proteins

• Refractive Errors

Refractive errors are a type of eye ocular disease that is caused by a change in the shape of the eye or the eye's membrane protein. This change causes light to be refracted, or bent, as it passes through the eye. This results in a blurred image. Refractive errors include myopia, hyperopia, and astigmatism. Myopia, or nearsightedness, occurs when the eye is too long or the cornea is too curved. This causes light to be focused in front of the retina, resulting in a blurred image. Hyperopia, or farsightedness, occurs when the eye is too short or the cornea is too flat. This causes light to be focused behind the retina, resulting in a blurred image. Astigmatism occurs when the eye is not perfectly round. This results in two focal points, one in front of the retina and one behind it. As a result, images may appear blurred or distorted. Refractive errors can be corrected with eyeglasses, contact lenses, or refractive surgery.

Cx36 is a membrane protein that is predominantly expressed in eye tissue. Mutations in the Cx36 gene have been linked to several ocular diseases, including refractive errors. Refractive errors are a type of eye disorder that affects the eye's ability to focus light properly. This can lead to blurred vision and difficulty seeing objects at a distance. Several studies have shown that targeting Cx36 can help to treat refractive errors. For example, one study found that Cx36-knockout mice had reduced eye growth and improved visual acuity. These findings suggest that targeting Cx36 may be a promising treatment for refractive errors.

Fig.2 Illustration of different types of refractive error and their correction with lenses. (Latz, et al., 2021)

• Cataract

A cataract is an eye disease that causes the ocular lens to become cloudy or opaque. This can lead to vision problems and, in severe cases, blindness. Cataracts are most caused by aging or exposure to ultraviolet light, but they can also be hereditary. There are many different types of cataracts, but they all share one common feature: the accumulation of abnormal proteins in the eye's lens. These proteins prevent light from passing through the lens.

Fig.3 Formation of cataract. (Zaki, et al., 2020)

In order to better understand this disease, researchers have been studying a membrane protein known as CryAB. Mutations in this protein have been linked to cataracts, and it is thought that understanding how the protein works could lead to new treatments for this eye condition. Studies have shown that CryAB plays a role in controlling the clarity of the eye's lens. When the protein is not functioning properly, it can cause the lens to become cloudy and opaque. Researchers are hopeful that by better understanding this protein, they will be able to develop new treatments for cataracts that can improve the quality of life for those affected by this eye condition.

Fig.4 Cataractogenesis involves the aggregation of crystallin proteins as well as multilamellar bodies in the lens. (Quinlan, 2015)

• Glaucoma

Glaucoma is a degenerative eye disease that typically results in optic nerve damage and vision loss. It is often associated with an increase in eye pressure, although not all cases of glaucoma are caused by high eye pressure. In fact, some forms of glaucoma can be caused by a variety of factors, including genetics and trauma. There is no cure for glaucoma, but early detection and treatment can help to slow the progression of the disease and preserve vision.

Fig.5 The anatomy of a healthy and glaucoma eye. (Hagiwara, et al., 2018)

One of the most important proteins involved in glaucoma is a membrane protein, AQP1 (Aquaporin-1). AQP1 is found in eye tissues and helps to regulate eye pressure by controlling the flow of water into and out of the eye. Mutations in the AQP1 gene have been linked to primary open-angle glaucoma (POAG), the most common form of glaucoma. Although AQP1 mutations are relatively rare, they are thought to play a role in up to 5% of all cases of POAG. Research on AQP1 and other proteins involved in eye pressure regulation may help to identify new treatments for glaucoma.

Fig.6 AQP1 within the ciliary epithelium using CRISPR-Cas9. (Komaromy, 2020)

References

1. Cholkar, K.; et al. Novel nanomicellar formulation approaches for anterior and posterior segment ocular drug delivery. Recent Patents on Nanomedicine. 2012, 2(2): 82-95.
2. Latz, G.; et al. Femtosecond-laser assisted surgery of the eye: overview and impact of the low-energy concept. Micromachines. 2021, 12(2):122.
3. Zaki, U.; et al. Harmful effects of 5G on life with possible solution. Global Scientific Journals. 2020, 8(5): 1-13.
4. Quinlan, R.A. A new dawn for cataracts. Science. 2015, 350(6261): 636-637.
5. Hagiwara, Y.; et al. Computer-aided diagnosis of glaucoma using fundus images: A review. Computer Methods and Programs in Biomedicine. 2018, 165: 1-12.
6. Komaromy, A. CRIPSR-Cas9 disruption of aquaporin 1: an alternative to glaucoma eye drop therapy. Molecular Therapy. 2020, 28(3): 706-708.