Lec. 4 Refractive Error Development

What happens to the total power as you grow compared to birth?

Decreases approximately 90D to 60D

Growth to increase of power ratio?

1/3mm to 1.00D

Cornea’s power at birth

48D

What is the end goal for refractive error to any baby?

Low hyperopia to emmetropia

When does the most change happen?

1st year of life

What happens to axial length and corneal and lenticular power as we grow?

Increase AL and decrease corneal and lenticular powers

What is the rx for infants?

Avg. +2.00

What is not a reason for the eye to elongate?

Strabismus

What is not a reason for restrictive visual experience?

Ptosis

A 6 months infant came to your office for an eye exam. You try to retinoscope but pt would not let you. After playing with the pt finally you get a quick chance to do ret. You end up with a +3.50D, is this normal or abnormal

Abnormal

What is a normal hyperopia for a 6 month?

+3.00

What is a normal hyperopia for a 9-12 month?

+2.25

What is a normal hyperopia for a 18-30 month?

+2.00

What is a normal hyperopia for a 36-48 month?

+1.75

Avg. astg for patient 5 months to 3 years

Max -1.75

Avg. astg for patient 5 months to 3 years

Max -1.25

Avg Myopia for 5 months to 5 years

0.00

Avg Anisometropia for 5 months to 5 years

0.75

What happens when high lag at near (MEM) for hyperopia?

Increase risk of esotropia

What happens when high lag at near (MEM) for myopia?

Increase risk of myopia progression

Cyclo percentage under 1 year

0.5%

Cyclo percentage over 1 year

1.0%

If the pt has excessive accommodation & normal to high AC/A

Eso deviation

If the patient has inadequate accommodation to provide clear vision

Decreased VA

When does astigmatism should disappear?

by 3.5 years old

From birth to 3 years what meridian is more common?

ATR

After age 5 what meridian is more common?

WTR

Which meridional is more associated with the development of amblyopia?

ATR (dec. w/ age)

Which meridional is less common but result in high risk for amblyopia?

Oblique