Presbyopia Flashcards
in presbyopia, what would amp need to be?
near point of accommodation?
amp less than 5D (normal reading dist 16in or 40cm)
near point of acc beyond 20 cm (20cm=5D)
what is incipient presbyopia aka borderline presbypia or pre presbyopia
testing shows a need for plus at near, but the pt has no complaints and rejects the near rx when trial framed
what is the hess-gullstrand theory of presbyopia
presbyopia is the result of changes in the lens and lens capsule
what is the duane-fincham theory
presbyopia is the result of the weakening of the ciliary body
-has been disproven by newer studies
what is the chief complaint of presbyopes
my arms are too short
what is the onset of presbyopia by amp and clinically?
by amp: age 35-50
clinically: when the pt has near complaints due to the age-related decrease in his amp and needs an rx of plus for near
who becomes presbyopic faster, corrected hyperopes or myopes? why?
corrected hyperopes bc of lens effectivity
-actual acc is more for a hyperope than myope for the same dist measured at the spectacle plane (actual acc takes place at the crys lens)
what are some factors that affect the onset of pres?
refractive types (hyp earlier than myop)
usage of eyes: symp more apparent for pt w/ more nearwork
length of arms/height of pt
geographic location: earlier in pt living near the equator
medication: alc, cholopromazine, hydrocholothiazide, antianxiety meds, antidepressent, antipsychotics, antispasmodics, antihistamines, diuretics
as the pt ages, what happens to the amp?
what happens to the amt of plus?
amp decreases, the amt of plus needed increases
what is the near rx
what is the add
near rx=dist rx + add
add = near rx-dist rx
what are the steps to get add
- start w/ dist rx in phoropter
- select a tentative add by one of several methods
- refine the add (using the NRA/PRA)
- finalize the add or near rx by trial framing it
what are the methods for makeing tentative add
- age and refractive status
- fused cross cyl
- half the amp in reserve rule
- entering rx and near va
carlson’s quick method for selecting tentative add: age 40, 50, > 60
40: +1.00
50: +2.00
> 60: +2.50
in fused cross cyl, what lighting do you use when you place the target cross at 40 cm
DIM illumination
if your pt is over 50 years old, how much add do you add before asking them if vert or horiz clearer?
at least +1.00
