Refractive Elements Of The Eye

Refractive Elements Of The Eye

Question 1. Enumerate the various refractive media of the eyeball.
Answer.

The four refractive media in the eyeball, from before backwards are as follows:

• Cornea
• Aqueous humour
• Lens
• Vitreous body

Layers Of The Eyelid

The eyelids are mobile curtains of soft tissue to close and open the eyes. They protect the eye from dust particles and help in its moistening.

The layers of the eyelid: From outside to inside, these are as follows:

• Skin
• Superficial fascia
• Orbicularis oculi
• Tarsal plate of palpebral fascia
• Conjunctiva

Eyelids Applied anatomy

• Ptosis (drooping of upper eyelid): It occurs due to paralysis of the levator palpebrae superioris muscle.
• Stye (hordeolum): It is suppurative inflammation of glands of Zeis (i.e. sebaceous glands present in the eyelashes).
• Chalazion: It is the inflammation of the tarsal (meibomian) gland (a modified sebaceous gland in the tarsal plate).