Aios 2010 presentation 1
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This document summarizes information from an instruction course on glaucoma and visual field testing. It discusses when visual field tests are recommended, how the tests work, what the results show, and how to interpret them. Key points include that visual field tests measure retinal sensitivity, central 30 degrees of vision represent most ganglion cells, and results are analyzed for reliability, patterns of defects, and correlation to glaucoma diagnosis.
![2/20/2010Sudhalkar Eye Hospital, Baroda, Gujarat1Single field analysisbyDr.AnandSudhalkarAIOS 2010, Kolkatta. Instruction course no. 82 [IC76] GLAUCOMA –Basic Sunday, 24-1-2010](https://image.slidesharecdn.com/aios2010presentation1-100418080114-phpapp01/85/Aios-2010-presentation-1-1-320.jpg)
Aios 2010 presentation 1
- 1. 2/20/2010Sudhalkar Eye Hospital, Baroda, Gujarat1Single field analysisbyDr.AnandSudhalkarAIOS 2010, Kolkatta. Instruction course no. 82 [IC76] GLAUCOMA –Basic Sunday, 24-1-2010
- 2. Situations demanding Field Test Glaucoma Diagnostic Triad with IOP and Disc changes. IOP > 21mm Hg.Significant Cupping with/without high IOPStrong Family History, Myopia, DiabetesNarrow Angles/Int. IOPNormal “Other” Eye of the glaucoma patient2/20/2010
- 3. What are we testing?Actual visual fieldTested visual field60°FixationBlind spot90°60°30°Temporal fieldNasal field70°The central 30° field represents 66% of the ganglion cells and 83% of the visual cortexNearly all pathologies can be associated with loss of retinal sensitivity in the 30° visual fieldIf in doubt, it is recommended to repeat the central field rather than test the periphery2/20/2010Sudhalkar Eye Hospital, Baroda, Gujarat3
- 4. How is the field tested? Static PerimetryIn static perimetry every location is tested in a “vertical direction“ by making the stimulus dimmer and brighter Only psychophysical documentation with Quantification of visual loss in glaucomaComparison with age matched normative data Statistical, glaucoma specific analysis.Sudhalkar Eye Hospital, Baroda, Gujarat4Normal fieldPathologicalfield2/20/2010
- 5. What are we looking for?Is the visual field reliable?Pattern of defectsSignificance of defectsNormal or GlaucomaClinical correlationSudhalkar Eye Hospital, Baroda, Gujarat52/20/2010
- 6. Reading the chart2/20/2010Sudhalkar Eye Hospital, Baroda, Gujarat6Patient and examination dataMeasured values and greyscaleGHTDefect CurveComparison valuesVF IndicesProbability plotsEye fixation
- 7. Patient and examination data2/20/2010Sudhalkar Eye Hospital, Baroda, Gujarat7Pupil sizeProgram and strategyDate of birthQuestions, repetitions and catch trialsRefraction
- 8. VA grey-scale degradation with age2/20/20108Sudhalkar Eye Hospital, Baroda, Gujarat
- 9. Reliability check by:Fixation lossescatch trials2/20/20109Sudhalkar Eye Hospital, Baroda, Gujarat
- 10. Reliability check by catch trials Positive Catch TrialsWith the positive catch trials, the perimeter produces a stimulus sound although NO light is projected - the patient should not respond.With many positive mistakes, the patient is a “happy trigger” patient. 2/20/201010Sudhalkar Eye Hospital, Baroda, Gujarat
- 11. Reliability check by catch trials Negative Catch TrialsWith the negative catch trials, the perimeter projects its brightest spot where a less intense stimulus was seen before - the patient must respond!With severely depressed fields, the patient usually makes more mistakes. This is normal.2/20/201011Sudhalkar Eye Hospital, Baroda, Gujarat
- 12. Reliability check by catch trialsEvaluationThe Reliability Factor is the number in percent of the positive and negative catch trial mistakes.Whenever this factor exceeds 15-20% the results must be evaluated with caution.2/20/201012Sudhalkar Eye Hospital, Baroda, Gujarat
- 13. 2/20/2010Sudhalkar Eye Hospital, Baroda, Gujarat13Value table and VA grey-scaleThe VA grey-scale presents a comprehensive summary of the visual fieldThe measured values are the base for all further calculations and graphicsFoveal Threshold
- 14. Octopus Humphrey comparisonsMeasuring range in Decibel (dB)d.l. sensitivity luminance inDecibel(dB) in Apostilb (asb) Perimeter models 101 300 HFA 40 dB - 0.1 asb 0.4 asb 1 asb 30 - 1.0 4.0 10 20 - 10 40 100 10 - 100 400 1’000 0 - 1’000 4’000 10’000 Background (asb) 4 31.5 31.52/20/2010Sudhalkar Eye Hospital, Baroda, Gujarat14
- 15. Basic perimeter parameters2/20/2010Sudhalkar Eye Hospital, Baroda, Gujarat15Parameter OCTOPUS 101 OCTOPUS 300 HFABowl type Spherical bowl Direct projection A-spherical bowl 42.5 cm 18-30 cmBackground - Luminance 4 asb 31.4 asb 31.5 asb (1.27 cd/m²) (10 cd/m²) (10 cd/m²)Stimulus - Size Goldmann I - V Goldmann III, V Goldmann I - V- Duration 100 ms 100 ms 200 ms- Luminance 1’000 asb 4’800 asb 10’000 asb for 0 dB Measuring range 0 - 40 dB 0 - 40 dB 0 - 40 dBTest strategies 4-2-1 dB bracketing 4-2-1 dB bracketing 4-2 dB bracketing Dynamic strategy Dynamic strategy SITA Normal TOP TOP SITA FastNormal values Age correction per year of age
- 16. Comparison table and CO grey-scale:(difference (comparison) between the age-corrected normal data and the actual measured results)Actual Value tableAge matched comparison2/20/2010Sudhalkar Eye Hospital, Baroda, Gujarat16
- 17. Corrected comparisons table: depicts local defects relative to the mean diffuse depression In the “corrected” comparisons table the deviation value is taken into account to highlight pathological changes without the effect of any preretinalinterferences(mean diffuse depression of 8db)2/20/2010This table displays comparisons minus deviation18
- 18. CO valuesRankingThe cumulative defect (Bebie) curve2/20/2010Sudhalkar Eye Hospital, Baroda, Gujarat18The CO values are sorted in size and displayed in order (ranking) from the smallest to the largest defect
- 19. Typical defect curves2/20/2010Sudhalkar Eye Hospital, Baroda, Gujarat19Suspect field:incorrect date of birth or trial lenssmall pupil
- 20. cataract
- 21. early glaucomaNormal visual fieldFocal defecte.g. Early glaucoma
- 22. Visual Field Indices2/20/2010Sudhalkar Eye Hospital, Baroda, Gujarat20
- 23. Visual field indicesFor a quick assessment of the visual field it is helpful to average all values in a few (global) indices2/20/2010Sudhalkar Eye Hospital, Baroda, Gujarat21
- 24. Index - mean sensitivity (MS)2/20/2010Measured valuesNormal valuesMean sensitivity MSAverage of all measured valuesSudhalkar Eye Hospital, Baroda, Gujarat22
- 25. 2/20/2010Measured valuesMean defect (MD)Normal valuesMean sensitivity MSMean defect (MD)difference between average normal and MSSudhalkar Eye Hospital, Baroda, Gujarat23
- 26. Normal range of MD = -2 to +2 dBThe Mean Defect MD represents the average defect of the entire visual fieldMD reacts strongly on diffuse (homogeneous) depressionLocalized (topical) defects have practically no influence on MDMD is the index for uniform loss of sensitivity2/20/201024Sudhalkar Eye Hospital, Baroda, Gujarat
- 27. Loss variance (LV)2/20/2010MDMeasured valuesNormal valuesMSLoss variance (LV)Spread of measured values from MS25Sudhalkar Eye Hospital, Baroda, Gujarat
- 28. Normal range of LV = 0 to 6 dB2The index Loss variance (LV) is sensitive to the irregularity of the visual fieldNormal visual fields have an LV of 0 .. 6 dB2LV (or sLV) = standard deviation (sd)Normal visual fields have an sLV of 0 .. 2.5 dBAn elevated LV (or sLV) is an indication that the field has localized defects exceeding the normal local variability2/20/2010Sudhalkar Eye Hospital, Baroda, Gujarat26
- 29. Probability of defectsProbability plots helpful to signal the significance of a local defect2/20/2010P<0.5 means that less than 0.5% of the normal population shows a defect of this size at this location – Therefore this defect is a significant defect28
- 30. What are we looking at?Established glaucomatous damageNasal and upper hemifield defectsClassic arcuateBjerrumscotomaNasal Step respecting the horizontal rapheDifferentiate between generalized or diffuse against localized deep defects. Increased fluctuations in retinal sensitivity in those specific areas.2/20/2010Sudhalkar Eye Hospital, Baroda, Gujarat28
- 31. Diagnostic field defects in glaucomaLocations on chartThe visual field below demonstrates a cecocentralscotoma and superior nasal step and inferior nasal step with some extension into the acruate bundle.2/20/2010Sudhalkar Eye Hospital, Baroda, Gujarat29
- 32. Criteria for glaucomatous loss Early StageMD > 3 < 6dBFewer than 15 points affected with p < 5% and fewer than 8 points below p < 1% level2/20/2010Sudhalkar Eye Hospital, Baroda, Gujarat30
- 33. Criteria for glaucomatous loss Moderate StageMD > 6 < 12dBFewer than 30 points affected with p < 5% and fewer than 15 points below p < 1% level2/20/2010Sudhalkar Eye Hospital, Baroda, Gujarat31
- 34. Criteria for glaucomatous lossAdvanced StageMD > 12dBMore than 30 points affected with p < 5% and more than 15 points below p < 1% level2/20/2010Sudhalkar Eye Hospital, Baroda, Gujarat32
- 35. Same Patient comparison2/20/2010Sudhalkar Eye Hospital, Baroda, Gujarat33Early Field Loss
- 36. 2/20/2010Sudhalkar Eye Hospital, Baroda, Gujarat34Moderate Field Loss
- 37. 2/20/2010Sudhalkar Eye Hospital, Baroda, Gujarat35Severe Field Loss
- 38. PearlsCheck field for reliabilityLook for glaucoma specific losses/neurologicalCorrelate with disc cupping, NFL loss and IOP, complete fundus examination.Repeat fields : 1. If in doubt 2. Follow-up2/20/2010Sudhalkar Eye Hospital, Baroda, Gujarat36
- 39. Thank You2/20/2010Sudhalkar Eye Hospital, Baroda, Gujarat37
- 40. 2/20/2010Sudhalkar Eye Hospital, Baroda, Gujarat3855 yr Male, LE DV post op 6 months
- 41. 2/20/2010Sudhalkar Eye Hospital, Baroda, Gujarat39Field RELE
- 42. 2/20/2010Sudhalkar Eye Hospital, Baroda, Gujarat40
- 43. RELE2/20/2010Sudhalkar Eye Hospital, Baroda, Gujarat41