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Interpretation of fields

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Interpretation of fields

  1. 1. INTERPRETATION FIELDS OF
  2. 2. APPROACH 1 Check patient and test data 2 Obtain general impression 3 Observe defects and defect curve 4 Review statistics PATIENT DATA GREY SCALE COMPARISONS TDNP TEST DATA VALUES RAW DATA BABIE’S CURVE CORRECTED COMPARISONS PDNP PROBABILITY TDPP GLOBAL INDICES CORRECTEDD PROBABILITY PDPP
  3. 3. WANDER  What was done?  Accuracy (Reliability)  Normal or abnormal  Defect pattern  Evaluate compatible disease  Review
  4. 4. PATIENT DATA EXAMINATION DATA  Name • Programme  Age/sex • Strategy • Stage/ Phase • Test target/ duration ( Goldmann size III ) • Background illumination ( 31.5 apostilb )  Eye  Pupil size  V/A with refractive status
  5. 5. RELIABILITY • Fixation loss • False positive • False negative • Test duration • Question / repetition
  6. 6. FALSE POSITIVES FALSE NEGATIVES
  7. 7. PITFALLS Performing perimetry Data entry Pupil size Refractive error Recognising artefacts Fatigue effect Reliability Co existing ocular morbidity Learning curve
  8. 8. GREY SCALE
  9. 9. PATIENT’S RETINAL SENSITIVITY NORMAL RETINAL SENSITIVITY DIFFERENCE HUMPHREY OCTOPUS TOTAL DEVIATION NUMERICAL PLOT COMPARISON
  10. 10. PROBABILITY PLOT
  11. 11. ELIMINATING GENERALISED DEPRESSION
  12. 12. ELIMINATING GENERALISED DEPRESSION OCTOPUS CORRECTED COMPARISONS HUMPHREY PATTERN DEVIATION NUMERICAL PLOT
  13. 13. BEBIE CURVE CO values Ranking
  14. 14. GLAUCOMA HEMIFIELD TEST RESULTS Outside normal limits p <1% Borderline p <3% Generalized reduction of sensitivity Abnormally high sensitivity Within normal limits
  15. 15. ANDERSON’S CRITERIA 3 GHT – outside normal limits 2 CPSD 4 dB P <5% 1
  16. 16. ANDERSON’S CRITERIA
  17. 17. GLOBAL OR STATISTICAL INDICES HUMPHREY MD PSD SF CPSD OCTOPUS MD LV RMS CLV
  18. 18. GLOBAL INDICES - MD A B
  19. 19. GLOBAL INDICES - MD -2 (<-6dB) MILD GENERALISED DEPRESSION -7 (<-12dB) MODERATE GENERALISED DEPRESSION -13 (>-12dB) SEVERE GENERALISED DEPRESSION MD -2.18 dB
  20. 20. GLOBAL INDICES – PSD OR LV MEAN 150 STANDARD DEVIATION 150 0 160 140 150 10 170 110 150 40
  21. 21. GLOBAL INDICES – PSD OR LV PSD 4.63dB p < 1%
  22. 22. GLOBAL INDICES HEIGHT (MEAN DEVIATION) MD: NORMAL PSD: NORMAL MD: ABNORMAL PSD: NORMAL SHAPE (PATTERN STD DEVIATION) MD: NORMAL PSD: ABNORMAL MD: ABNORMAL PSD: ABNORMAL
  23. 23. SHORT TERM FLUCTUATION PATTERN STANDARD DEVIATION CORRECTED PATTERN STANDARD DEVIATION SF IN A RELIABLE FIELD: 1 – 2.5 dB
  24. 24. FIELD DEFECTS IN GLAUCOMA  Generalised loss- Early and non-specific  Localised loss- More specific  Advanced field loss
  25. 25. THANK YOU
  26. 26. RAW DATA OR VALUES
  27. 27. RIM ARTEFACTS
  28. 28. SIZE OF THE PUPIL 2.2 mm 5.0 mm
  29. 29. DEVIATION OR COMPARISON PLOTS & PROBABILITY
  30. 30. 30 30 32 29 31 33 30 31 33 31 32 31 5 + 7 + + + 9 + + + 5 + + + 7 + + + 5 5 + + + + + + + + + + 5 + + + + + + + + + + + + + + 5 + + 29 31 33 33 33 33 32 31 29 31 33 34 34 33 32 31 21 + + 23 28 24 27 29 + 27 27 30 + 27 27 28 29 31 32 34 34 33 32 31 28 27 26 30 32 31 27 26 29 30 32 33 33 33 32 32 27 29 30 31 33 32 29 29 31 31 31 00 32 00 32 32 32 32 28 29 28 32 32 30 30 28 29 26 28 29 32 31 28 29 27 26 00 00 30 29 28 30 30 30
  31. 31. Global Indices • All the information from all the points tested is reduced to single numbers
  32. 32. Global Indices : Mean Deviation or Mean Defect (MD ) • Mean of deviation of the visual field from normal. MD -2.18dB
  33. 33. Global Indices Pattern Standard Deviation (PSD) / Loss Variance (LV) • Standard deviation of deviation • Indicates the degree to which the numbers differ from each other • “Roughness” or “potholes” in the hill of vision PSD 4.63dB p < 1%
  34. 34. Sequential single field analysis’ Printed Data a. Name b. Test c. DOB d. Parameters (check for standard size III) e. Visual Acuity f. Refraction g. Pupil Diameter (>3mm)
  35. 35. Sequential single field analysis Reliability factors a. Fixation loss (< 20%) b. False positive (<33%) c. False negative (<33%) d. Foveal Threshold (acuity & MD) Gray scale a. Overall Depression b. Specific loci of defects
  36. 36. Sequential single field analysis Total Deviation plots a. Numeric Plot (scan briefly the numbers) b. Probability map (clustering of high p-value) Pattern deviation Plots a. Numeric plot (ignore) b. Probability map (compare to Total Deviation map)
  37. 37. Sequential single field analysis Numeric Data display Investigate suspicious area in total deviation map Review raw data in a geographic sequence Perifoveal values Arcuate regions Around blind spot Nasal step Vertical and Horizontal axes Peripheral areas
  38. 38. Sequential single field analysis Global Indices MD (cf acuity and foveal threshold) PSD (localised defect ) Glaucoma Hemifield Test
  39. 39. Glaucoma Hemifield Test  5 sectors in upper field are compared to 5 mirror images in the lower  Nerve fibre layer defect occurs assymetrically between hemifield
  40. 40. 4 3 2 1 5
  41. 41. Glaucoma Hemifield Test  Outside normal limits p <1%  Borderline p <3%  Generalized reduction of sensitivity  Abnormally high sensitivity  Within normal limits

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