Optometry Club - A.K.D

Describe about the Lacrimal apparatus 👁️ ?

The lacrimal apparatus is the physiological system containing the orbital structures for tear production and drainage.
It consists of The lacrimal gland, which secretes the tears, and its excretory ducts, which convey the fluid to the surface of the eye; it is a j-shaped serous gland located in lacrimal fossa.

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✅ What is Refraction?
Refraction is the bending (change in direction) of light rays when they pass from one transparent medium to another medium of different density.
In the human eye, refraction occurs mainly at:
Cornea (major refraction ~ 2/3rd)
Crystalline lens (fine focusing)
This bending of light helps to focus the image exactly on the retina, so that we can see clearly.

✅ Definition (Clinical)

Refraction is the process of determining the refractive power of the eye and prescribing suitable lenses to obtain clear vision.

✅ Physics Concept (Important)
Refraction follows Snell's Law, which explains how light bends when it moves between different media (like air → cornea).

✅ Types of Refraction (In Optometry)

1️⃣ Objective Refraction
* Done without patient response
* Examples:
* Retinoscopy
* Auto-refractometer

2️⃣ Subjective Refraction
Done with patient response
Example:
* Trial frame & trial lenses
Phoropter test.

✅ Types of Refractive Errors (Found During Refraction)
* Myopia (near sightedness) 🔎
* Hypermetropia (far sightedness) 🌄
* Astigmatism 🎯
* Presbyopia 👓

✅ Purpose of Refraction :-

⭐ To determine glasses power
⭐ To improve visual acuity
⭐ To diagnose refractive errors
⭐ Important before contact lens fitting / cataract surgery

✅ Simple Example
When light enters from air → water, it bends.
Similarly, when light enters air → cornea → lens → retina, refraction helps to form a clear image.
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