Candidate 20                      MCQ topics in Nov, 2002 part II MRCOphth

  1. Photometry 
  -troland can be used to measure retinal illumination 
  -similar to what is given in past mcqs on this web site 

  2. Prisms 

  -put base out to correct exotropia 
  -can correct torsional diplopia 
  -power of prism can be calculated by axial power multiplied by cosine of angle. 

  3. Reduced eye 

  -approximate power is 60D 
  -axial length is 22.5 mm 
  -nodal point is one at which visual angle is formed 

  4. Spherical aberration 

  -causes bull's-eye retinoscopic reflex in young children 
  -is dependant on radius of curvature 
  -reduces with aspheric lenses 

  5. Safety glasses 

  -laminated glasses donít have sharp edges when shattered 
  -if laminated can only be produced in spherical form and not cylindrical. 
  -polycarbonate is tough material. 

  6. Hruby's lens 

  - is a contact lens
  - gives a minified view of the retina
  - forms a real inverted image. 
  - used with concave surface towards patient 

  7. Indirect ophthalmoscope 

  -field of view is larger in myopia. 
  -when a fixed power lens is used at fixed distant from eye, myopic image is 
    smaller than hypermetropic. 
  -better pupil dilatation is required for binocular than uniocular indirect 

  8. Direct ophthalmoscopy

  -magnification is 15 times in emmetropic eye. 
  -refractive error affects direct ophthalmoscopy. 

  9. Jackson cross cylinder

-is composed of equal-power, perpendicular plus and minus cylinders
-has a handle 45 degrees to the axes
-spherical equivalent is 0

  10. Applanation tonometry 

  -area flattened is 13.06mm square. 
  -based on imbert=fick principle 
  -appropriate area of applanation is achieved when whole tonometer head touches the cornea 
  -IOP can be calculated by the formula area=force/IOP 

  11. Different reading adds required in 

  -Argyll Robertson pupil 
  -unilateral Adie's pupil 
  -one eye phakic and other pseudophakic 

  12. Lens form 

  -toric lens gas spherocylindrical surface in both the meridians 
  -spherocylindrical lens has spherical surface in one meridian and cylindrical in the other 
  -BC of plus toric lens is on its ant surface 
  -meniscus lenses reduces aberration 

  13. When light enters from denser to a rarer medium 

  -total internal reflection occurs always 
  -blue light is refracted more 
  -its deviated towards the normal 

  14. Exotropia 

  -is overestimated with convex lenses 
  -can be corrected with Wollaston prisms 

  15. Alternate cover test 

  -should always be performed before cover-uncover test 
  -if both eyes move in on's esophoria 
  -putting neutral density filter in front of one eye will affect the result 

  16. Saccades 

  -lasts for 0.002 seconds 
  -visual information is suppressed while saccade is taking place 
  -it is increased in hypermetropia 
  17. Amblyopia 
  -neutral density filter reduces visual acuity 
  -RAPD may be present in otherwise normal eye 
  -VEP is generally abnormal 

  18. Simulated blindness can be detected by 

  -worth four dot test 
  -lang stereo test 
  -retinoscopy no subjective correction 
  - VA is better that 6/18, if pupils are normal reacting 

  19. Restricted myopathy 

  -have reduced saccades in all direction of gaze 
  -forced duction test will be positive 

  20. Stereo test 

  -Titmus uses vectograph 
  -TNO is used with red green glasses 
  -Lang can be used in very small children 

  21. Keratometer 

  -J-S uses fixed image size and variable object size 
  -measures only central cornea 
  -can measure axis and power of astigmatism 
  -utilizes images formed by post corneal surface 

  22. Laser 

  -excimer uses active gas with 2 halogen molecules 
  -excimer penetrates corn 20microm 
  -it produces photochemical ablation 
  -picosecond lasers strip electrons & form a cavitation bubble-termed photodisruption 

  23. If -10.0D myope change from spec to contact lenses 

  -VF increases 
  -peri aberrations reduces 
  -symptom of presbyopia more prominent 
  -image size is reduced 

  24. Following associations are true 

  -childhood refraction and WTR astigmatism 
  -myopia and flat cornea 
  -myopia and long axial length 
  -keratoconus and oil droplet reflex on RETINOSCOPY 
  -congruous hemianopia and cortical lesion 

  25. Telescopic LVA 

  -nonpresbyopic patients can use same device for distant and near by using their accommodation 
  -increases the outdoor mobility 
  -increasing the aperture of objective lens will increase field of view 

  26. Maddox rod in front of right eye 

  -if line is seen to left of spot then it's exophoria 
  -for cyclo measurement another MR is put in front of left eye which can be either white or green 

  27. Adult patient with ptosis, you'll like to check 

  -cover test in upgaze
  -ptosis max in sustained upgaze 
  -"      " in lateral gaze 
  -ask history of contact lens wear
  -examination of upper fornix 

  28. In case of pupil abnormality, you'll check 

  -heterochromia irides 
  -iris examination on slit lamp 
  -ant chamber examination on slit lamp 

  29. Concave mirror 

  -if object is on centre of rotation image size will be same 
  -if object outside the C image always inverted 
  -if object inside the C always virtual image formed 

  30. Specular reflection 

  -used to measure corneal epithelium 
  -angle of incidence is equal to angle of reflection 

  31. ERG 

  -a wave represents RPE 
  -measured by putting electrodes on medial and lateral canthi 
  -cone function can be isolated by using flicker fusion 

  32. Visual fields

  -damage to outer retinal layers produces blue-yellow defects 
  -can be snail shaped sometimes in RP 

  33. Sac syringing 

  -hard stop indicates common canalicular block 
  -while doing s/s through' lower canaliculi, fluid can regurgitate through' upper canaliculi in presence of patent drainage system 
  -punctum and position of lower lid should be examined in upright position 
  -if punctum is absent always indicates past inflammation or injury. 

  34. Doppler ultrasound 

  -detects flow by change in frequency of reflected echo 
  -can only determine flow towards the probe 
  -is most useful in vascular lesion of ciliary body 
  -can quantify blood flow of a tumour. 

  35. MRI 

  -eye make up should be removed before MRI 
  -possible IOFB is contraindication for MRI 

  36. B-scan

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