External Anatomy of the Eye | Eyes are organs of the visual system. They provide animals with vision, the ability to receive and process visual detail, as well as enabling several photo response functions that are independent of vision. Eyes detect light and convert it into electro-chemical impulses in neurons.
Table of Contents
Dimensions of an adult eyeball
- Axial Length (Anteroposterior diameter) 24 mm
- Horizontal diameter 23.5 mm
- Vertical diameter 23 mm
- Circumference 75 mm
- Volume 6.5 ml
- Weight 7 gram
Parts of the eye
Figure : Eye Anatomy |
Parts of the outer eye
- Eye Brows
- Eye Lids
- Extra Ocular Muscle
- Lacrimal Glands
- Lacrimal Apparatus
Segments of an eyeball
The human eye is divided into 2 segments:
1. Anterior Segment
2. Posterior Segments
Anterior Segments
It includes the parts from Cornea to the crystalline lens.
- Cornea
- Anterior Chamber
- Iris
- Posterior Chamber
- Lens
Posterior Segments
It includes the structures posterior to lens,
- Vitreous humour
- Retina,
- Choroid
- Optic Disc
Eye Brows
EyeLids
Anatomy of EyeLid
Functions
- Acts as a shutter which help to protect from trauma and excessive light.
- It spread tear film over the Cornea and conjunctiva.
- Better Cosmetic appearance
Parts of eyelids
- Skin
- Layer of Subcutaneous areolar tissues
- Layer of Striated muscle (Orbicularis oculi muscle, The levator palpebrae superioris muscle)
- Submuscular areolar tissue
- Fibrous Layer
- Layer of non-striated muscle fibres (Mullers muscle)
- Conjunctiva (Palperbral Conjunctiva)
Glands of Eyelids
- Meibomian glands
- Glands of Zeis
- Glands of Moll
- Accessory lacrimal glands of Wolfring
Tear Film
Conjunctiva
Parts of Conjunctiva
- Palpebral conjunctiva
- Bulbar conjunctiva
- Conjunctival fornix.
Conjunctiva Parts | Source https://quizlet.com/ |
Anatomy of Eye : Cornea
Layers of Cornea
- Epithelium
- Bowman’s membrane
- Stroma
- Pre-Descemet Layer, or Dua Layer
- Descemet’s membrane
- Endothelium
Parts of the Human Cornea |
Functions of Cornea
- It focuses light on the retina for image formation.
- Protects the intraocular contents.
Sclera
- Episclera
- Sclera proper
- Lamina fusca
Anatomy of the UVEA
- Iris
- Ciliary Body
- Choroid
Source: https://www.jaypeedigital.com/ |
Iris
Muscle of Iris
Ciliary Body
Choroid
- It is posterior part of uvea.
- This is a vascular sheet which separates sclera from retina.
Crystalline Lens
Structure of Lens:
- Anterior lens capsule
- Anterior lens epithelium
- Lens Nucleus – consists of elongated lens fibres
- Contains 64% water, 35% Protein (crystallin), 1% Lipids (Cholesterol, sphingomyelin, lipoproteins)
Vitreous Cavity
Retina
Layers of Retina
Layers of Retina | Source: www.memorangapp.com |