Accommodation And Presbyopia Flashcards
You have a -2.oo D myopic patient that has an accommodative amplitude of 8 D. What is their near point?
2+8=10
1/10=0.1m
10cm
Your emmetropic patient wants to read their computer monitor at 0.8m. What us the minimum accommodation necessary to see the monitor clearly. Assume +-0.25D depth of focus
4/5=5/4=1.25D
1.25-0.25=1.00D
You have a +2.00D uncorrected hyperope with an accommodative amplitude of 6D. What is a comfortable close distance for them for long periods of time (1/2 their AA)
+2.00 hyperopia
6D AA (3 for comfort)
3-2=1D left
1m
Normal aging process of the eye
Presbyopia
The age related continuous but gradual loss of accommodation
Presbyopia
The function whereby the converging power of the optical. System of the eye is increaes so that light diverging from a near source may be brought to a focus upon the retina
Accommodation
A process whereby the young eye is able to change the point of focus from a distance object to a near object
Accommodation
Other terms for presbyopia
- normal decreasing elasticity of the crystalline lens that leads to loss of accommodation
- accommodation insufficiency
- accommodative insufficiency
- presbyopia
Who is at risk for presbyopia
Anyone over the age of 35
Signs and symptoms of presbyopia
- hard time reading small print
- having to hold things at arms distance
- problems seeing objects that are close to you
- headaches
- eye strain
Needing optical correcting to the best distance correction to achieve an acceptable near VA (add on top of distance vision)
Objective hyperopia
Needing optical correction to the presenting distance correction to achieve acceptable near VA
Functional presbyopia
How many people world wide have presbyopia
1 billion
How many people lack adequate presbyopia correction
Half
What is the projected number of presbyopes in 2020
1.37 bil;lion
Symptom of presbyopia
- ocular discomfort with sustained near work
- drowsiness during near work
- holding stuff further away
- asthenopia related to excessive accommodative efforts
- transient diplopia or esophoria
What is the most recent theory of accommodation that says that the ciliary muscle relaxes and zonular fibers at ‘resting’ tension cause lens to contract and increase dioptric power?
Herman von helmholtz