Chua 5 Flashcards
How is visual acuity measured?
Uniocularly for near, distance
What to do when refracting nystagmus patient
Fog fellow eye with high plus lens
Complete occlusion worsens nystagmus
What is the purpose of fogging?
REduced or eliminates accommodation
Plus sphere to plus correction or reduce minus sphere in minus correction
End point is most plus power or least minus that gives best vision
How is accommodation reduced in objective refraction
Get patient to look at distance or using cycloplegia
When sleeve is placed in plane mirror position what movmeent is observed
With motion in hypermetropia
Against motion in myopia
What sleeve is placed in concave mirror position what movement is observed
Against motion in hypermetropia
With motion in myopia
How is working distance related to power of distance lens
Inversely proportional
What does use of minus cylinder inrefration cause in young vs older people
In young hypermetrope - repvents stimulation or accommodation
In elderly, may over correct the hypermetrope (and in cycloplegic refration)
Streak retinoscopy at x degrees
That is the axis - power is required at 90 degrees from this
Order of testing power/axis
SPH then axis then CYL
When can duochrome test be used
SPH is corrected within 1D or emmetropia
If red is clearer - myopic or overplussed
For a patient with accommodative esotropia what must be done to measure IPD
Both eyes in primary position - with correcting lens or using cover test
What can reduce exophoria?
Correction of myopia due to stimualtion of accommodation (convergence)
What happens to image if correcting lens is moved forward?
MOves forward irrespectiv eof concave or convex
How may a hypermetrope read in early presbyopia
Move glasses away from eyes
