Cornea | कॉर्निया
Why in News?
The Union Ministry of Health and Family Welfare amended the Transplantation of Human Organs and Tissues Rules in 2025 to simplify requirements relating to corneal transplantation centres and support expansion of cornea donation and transplantation services.
What is the Cornea?
The cornea is the transparent, dome-shaped outer layer at the front of the eye. It covers the iris, pupil and anterior chamber and is the first major optical surface through which light enters the eye.
Main Function
The cornea's primary optical function is to refract or bend incoming light so that it can be focused correctly. It does not primarily transmit visual nerve signals to the brain; that role ultimately involves the retina and optic nerve.
Focusing Power
The cornea provides approximately two-thirds, or about 65-75 percent, of the eye's total focusing power. The crystalline lens provides much of the remaining adjustable focusing ability.
Blood Vessels
The central cornea normally contains no blood vessels, helping it remain transparent. It receives oxygen and nutrients from tears, aqueous humour and surrounding tissues.
Nerve Supply
The cornea has a very rich sensory nerve supply and is highly sensitive to pain and touch. This sensitivity helps trigger rapid protective responses such as blinking.
Cornea and UV Protection
The cornea absorbs and filters part of the ultraviolet radiation entering the eye, contributing to protection of deeper ocular structures.
Refractive Errors
Irregular corneal curvature can contribute to refractive errors such as astigmatism. Corneal shape also plays an important role in overall focusing in myopia and hyperopia.
Corneal Injury
Minor superficial abrasions often heal relatively quickly. Deeper injuries can result in scarring and loss of transparency, potentially reducing vision.
Corneal Transplantation
A corneal transplant replaces damaged or diseased corneal tissue with healthy donated tissue. Donated corneas can restore vision in selected forms of corneal blindness.
2025 Rule Amendment
The Transplantation of Human Organs and Tissues (Amendment) Rules, 2025 modified requirements applicable to corneal transplantation centres, including making a specified item of equipment optional in the relevant regulatory form.
Important Dates
- 1994: Parliament enacted the Transplantation of Human Organs Act.
- 2011: The law was amended and its scope expanded to tissues.
- 27 March 2014: The Transplantation of Human Organs and Tissues Rules, 2014 were notified.
- 6 November 2025: The Transplantation of Human Organs and Tissues (Amendment) Rules, 2025 were notified.
कॉर्निया | हिंदी में विस्तृत विवरण
कॉर्निया क्या है?
Cornea आंख के सामने स्थित पारदर्शी dome-shaped outer layer है। यह pupil, iris और anterior chamber के सामने होती है और आंख में प्रवेश करने वाले प्रकाश के लिए मुख्य optical surface का काम करती है।
मुख्य कार्य
Cornea का मुख्य कार्य incoming light को refract अर्थात मोड़ना है ताकि image सही प्रकार से focus हो सके। Nerve signals को brain तक भेजना इसका मुख्य कार्य नहीं है; visual information retina और optic nerve से संबंधित होती है।
Focusing Power
Cornea आंख की लगभग 65 से 75 percent focusing power प्रदान करती है। बाकी महत्वपूर्ण focusing crystalline lens द्वारा की जाती है।
Blood Vessels
Central cornea में सामान्यतः blood vessels नहीं होते, जिससे इसकी transparency बनी रहती है। इसे nutrients tears और aqueous humour से मिलते हैं।
Sensitivity
Cornea में बहुत अधिक sensory nerves होते हैं, इसलिए यह pain और touch के प्रति highly sensitive है।
Corneal Transplant
जब cornea disease या injury के कारण opaque या severely damaged हो जाए, तो selected patients में donor corneal tissue का transplantation vision restore करने में सहायता कर सकता है।
महत्वपूर्ण तिथियाँ
- 1994: Transplantation of Human Organs Act enacted।
- 2011: Law का scope tissues तक विस्तारित किया गया।
- 27 मार्च 2014: संबंधित Rules notified।
- 6 नवंबर 2025: Corneal transplantation requirements से संबंधित Amendment Rules notified।