Anatomy of lens

 what is lens then. we'll cover shape of lens with lens dimensions and terms related to that then we'll look into location of lens that way the lens is situated in the eye and its attachments then parts of the lens and lens structure start with.

what is lens so lens is a transparent a vascular refracting structure in the eye which helps in focusing light rays on the retina and as lens takes part in refraction of light lens should have some power so what is the power of lens and the answer is lens contributes about a one third to the total power of i which is about 15 to 17 diopters next is shape of lens and terms relate to that so shape of lens is spherical at birth and by convex in adults as you can see in this picture the biconvex shape of lens in which the posterior surface is more curved than the anterior surface so here if i talk about radius of curvature of these surfaces then radius of curvature is always inversely proportional to the curvature itself and as anterior surface is less curved or i can say flatter so if i draw a complete circle for this curvature then this would be radius of curvature of anterior surface which is about 10 millimeter and if i make a complete or full circle for posterior surface which is more curved than the anterior surface or i can say steeper then this would be radius of curvature of posterior surface which is about six millimeter and i think now you got it that more curved surface has lesser radius of curvature and less curved surface has more radius of curvature now there are two points to know on interior and posterior surface of lens are anterior pole and posterior pole in which anterior pole is the center of anterior surface and posterior pole is the center of posterior surface and distance between these poles is measured as thickness of lens or entire posterior diameter of the lens which is about three millimeter at birth and increase to about six millimeter in older age so we talked about shape of lens which is by convex but by convex is in cross sectional view if we see lengths from front or back of the eye then lens has a circular shape so length is a combination of two circles interiorly and posteriorly and where these two circles meet we call this as equator of the lens and in cross sectional view we say these two points as equator which is actually a complete circumference now equatorial diameter of lens is about 6.5 millimeter at birth which reaches to 9 to 10 millimeter in adults and it is generally measured in nasal to temporal dimension now how the lens is suspended at its place so the reason for that is the equator of the lens is surrounded by ciliary zonules or called suspensory ligaments which has the one end attached to the lens incomplete 360 degree circumference and the other end is attached to the ciliary processes of ciliary body now we will see location of lens so the basic location of lens is behind the iris and in front of the waitress or can say lens is in contact with aquasumer anteriorly and vitrous humor posteriorly and posteriorly the transparent twitter's gel has a shallow depression in which lens is placed that depression in vitro's gel is known as patellar fossa and there is a little space present between this particular fossa and posterior surface of lens which is known as burgers space or retro lentil space now we know that lens is situated in particular fossa but how is it attached to vitreous gel so the attachment between posterior surface of lens and anterior vitreous is in a circular fashion by a ligament known as vigor's ligament or haloid capsular and the strength of this attachment decreases with age now next is lens structure or parts of lens so histologically lens is basically composed of three structures and these structures are lens capsule anterior lens epithelium and lens fibers which will see each one by one start with lens capsule so when we say.