Macular function test before cataract surgery 4 9-10


Published on

Prediction of visual gain after cataract surgery depends on the assessment of retinal function.

Published in: Health & Medicine

Macular function test before cataract surgery 4 9-10

  1. 1. Macular Function test before cataract surgery Ophthaglance 2, Sept 4-5 2010<br />Dr AnandSudhalkar, Vadodara<br />1<br /><br />
  2. 2. Expectations after cataract surgery<br />Improvement in vision<br />Achieve “Full” vision (6/6) ?<br />Achieve “Better than normal” vision (6/5) ?<br /><br />2<br />
  3. 3. The answer depends on:<br />Surgical success?<br /> Achieve the best “Optical Correction”<br />Visual Success:<br />Function of retina, visual pathway and occipital lobe, neuroadaptation and other “higher” functions.<br /><br />3<br />
  4. 4. Macular Functions<br />Fovea: Acuity of vision<br />Colour vision<br /> Day time adaptation<br />Peri and Paramacular region:<br />Mesopic and night vision<br />Refixation reflexes <br /><br />4<br />
  5. 5. Macular Function tests<br />Basic preop assessment<br />Refraction: Snellen Acuity<br />Amblyopia<br /> NEAR vision (Vryghem Macular Function Test charts)<br />Pinhole vision, <br />Ishihara charts<br />Maddox rod Two point discrimination <br />Photostress test<br />Amsler grid<br />Entoptic phenomenon<br />Slit-Lamp: Post sub capsular<br />Dilated fundus: Macular pathology<br />Special tests for fovea<br />Contrast sensitivity<br />Glare disability<br />Potential acuity meter<br />Perimetry<br />Optokineticnystagmus<br />FFA<br />B-scan<br />OCT<br />ERG<br />VEP<br /><br />5<br />
  6. 6. Maddox Rod test<br />Simplest, most reliable test(opaque med). <br />Rod consists of several cylinders of glass placed side by side in a frame. <br />Pt is asked to fixate light at a distance of 1/3 m through M.R. with opposite eye occluded. <br />Image formed is a straight line(vertical/horizontal streak) running perpendicular to the axis of rods. <br />Any breaks/holes; discoloration/distortion indicates a macular lesion. <br />RED: more sensitive, tells us about colour perception<br />Rotate the rod to test different meridians. <br /><br />6<br />
  7. 7. Two point discrimination test<br />The ability to distinguish two illuminated points of light suggests good retinal function. <br />•“Rule of 2” : Two illuminated points of 2 mm diameter size and 2 inches apart are placed 2feet away from the patient’s eye. The patient is then asked to indicate whether he canperceive the two points separately <br /><br />7<br />
  8. 8. The blue field entoptic phenomenon or Scheerer's phenomenonBlue field entoptic phenomenon in cataract patients. Arch Ophthalmol. 1979 Jun;97(6):1092-5. Sinclair SH, Loebl M, Riva CE.<br />In predicting normal macular function: <br />87% for the two-light discrimination test <br /> 94% for the BFE test.<br />In pathological conditions:<br />BFE test identified more than 75% of the poor maculae; the Purkinje vascular entoptic test and the two-light discrimination test, only 22%; and the colour perception test, 11%. <br />A positive response to the BFE test indicated a .98 probability of good macular function; a negative response indicated a .82 probability of poor macular function, predictions that were better than the other three tests or their combination.<br /><br />8<br />
  9. 9. Preop Retinal ExaminationIndirect Ophthalmoscopy<br /><br />9<br />
  10. 10. Practical Pearls<br />Awareness regarding macular Pathology<br />Diagnose and Identify Treatable pathologies and give them the priority over the cataract surgical procedure<br />Patient counseling and spending preop “Chair time”<br />“Acceptable” visual gain and success in an otherwise perfectly executed cataract surgery.<br /><br />10<br />