Anatomy of the Sclera


The sclera is the white, opaque, fibrous coat of the eye that surrounds the iris, ciliary body and the choroid. It is the outermost layer of the eye and forms the protective wall of the eye. It is composed of dense, fibrous connective tissue and gives the eye its shape and support. The sclera is essential for maintaining the structural integrity of the eye and protecting it from injury. In this article, we will discuss the anatomy and functions of the sclera in detail.

Structure of the Sclera

The sclera is a tough, fibrous structure that covers the majority of the eye. It is composed of collagen fibers and elastic fibers, which provide strength and elasticity. The sclera is thicker at the posterior pole of the eye, where it covers the optic nerve and the choroid, and thinner at the anterior pole, where it covers the cornea. The sclera is continuous with the cornea at the limbus, which is the junction between the sclera and the cornea.

The sclera is divided into three layers: the episclera, the stroma, and the lamina fusca. The episclera is the outermost layer and is composed of loose connective tissue. The stroma is the middle layer and is composed of densely packed collagen fibers. The lamina fusca is the innermost layer and is a thin, pigmented layer that helps to protect the eye from light.

Functions of the Sclera

The sclera plays several important roles in maintaining the structural integrity and function of the eye. Some of the key functions of the sclera include:

  1. Protection: The sclera serves as a protective barrier for the eye, shielding it from external threats such as injury, infection, and inflammation. It also helps to protect the eye from the pressure of intraocular fluids.
  2. Support: The sclera provides structural support for the eye, helping to maintain its shape and position. It also helps to support the muscles that control eye movement and the blood vessels that supply the eye with oxygen and nutrients.
  3. Maintaining the intraocular pressure: The sclera is a part of the wall of the eye, which helps in maintaining the intraocular pressure. This pressure is necessary for the proper functioning of the eye.
  4. Reflection: The sclera also reflects light back into the eye, helping to improve visual acuity.
  5. Maintaining the shape: The sclera helps to keep the eye in its spherical shape, which is necessary for the proper functioning of the eye.

Clinical Significance

The sclera is an important structure that plays a vital role in maintaining the structural integrity and function of the eye. However, it can also be affected by various diseases and conditions. Some of the common disorders that affect the sclera include:

  1. Scleritis: Scleritis is an inflammation of the sclera that can cause pain, redness, and increased sensitivity to light. It can be caused by autoimmune disorders, infections, or other underlying health conditions.
  2. Scleromalacia: Scleromalacia is a condition that causes the sclera to become thin and weak, making it more susceptible to injury. It can be caused by systemic diseases such as rheumatoid arthritis or by local conditions such as scleritis.
  3. Degenerative disorders: Degenerative disorders such as age-related macular degeneration can also affect the scl

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