Correction of Ametropia

Ametropia

Anything else besides emmetropia

Myopia

Has decreased accommodative demand

Hyperopia

Has increased accommodative demand

RE of less than 4.00D…

Are considered combinations of refractive and axial

RE of more than 4.00D…

Are generally axial in nature

Far point

Obj point that is conjugate with retina with fully relaxed accommodation

Near point

Obj point that is conjugate with retina with full accommodation

Amplitude of accommodation

Dioptric difference between FP and NP

NP for emmetrope, myope, and hyperope

M: Closest

H: Farthest

E: Somewhat far away

AA for uncorrected myopes and hyperopes

M: Overestimate

H: Underestimate

Over/under estimates equal to pts RE

Spectacle refraction

Power of the specs at the specified spec plane

Ocular refraction

Ametropia is specified at the first principal plane of the eye

Dist between corneal apex and first principal plane is very small → CL plane and ocular plane are the same

Ocular accommodation

Measured at the principal plane, must find vergence that leaves glasses if wearing specs

Vergence of distant obj - vergence of near obj

When corrected with specs, hyperopes and myopes need _____ accommodation than emmetropes

H: More

M: Less

Who will need presbyopic correction first?

Hyperopes

Spectacle accommodation

Assumes emmetropes and fully corrected ametropes all have the same accommodative demand for an obj at a given dist

if not fully corrected → adjust standard accommodative demand

Myopes accommodate less in…

Glasses

Hyperopes accommodate less in…

CL

The closer the obj comes to the eye…

The higher the accommodative demand

When spec corrected, myopes and hyperopes accommodate _____ than emmetropes

M: Less

H: More