Glaucoma basic principles part 1
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1. The document discusses the basic principles of glaucoma, including aqueous inflow and outflow mechanisms, methods of measuring intraocular pressure, optic disc and visual field evaluation in glaucoma diagnosis. 2. Key signs of glaucoma on optic disc examination are described as increased cup-to-disc ratio with asymmetry greater than 0.2, notching of the neuroretinal rim, and thinning or notching of the retinal nerve fiber layer. 3. Common visual field defects in glaucoma include central or paracentral scotomas, nasal steps, temporal wedges, and arcuate or double arcuate scotomas. Global indices on visual field analysis provide information about
Glaucoma basic principles part 1
- 1. Glaucoma basic principles part 1 Samhaa Mohammed Abd El Moneim Zagazig Ophthalmic Hospital
- 2. Glaucoma Aqeous inflow: Non pig ciliary epithelium of pars plicata • Active transport. • Ultrafiltration. • Diffusion. Aqeous outfow: • TM (90%). • Uveoscleal (10%). • Iris, retinal v, cornea.
- 3. Glaucoma Dx IOP causing optic n and field changes. 1. IOP 2. Optic disc 3. Visual field • OCT disc • Gonioscopy
- 4. Glaucoma case نفسك اسأل Type Risk factors Appropriate & avoided ttt acquired
- 5. Glaucoma Dx IOP causing optic n and field changes. 1. IOP 2. Optic disc 3. Visual field • OCT disc • Gonioscopy
- 6. IOP Applanation (goldmann) • Inappropriate fluroscein • Pressure on globe • Corneal odema • CCT • Astigmatism • Incorrect calibration • Frequent measure in short time Pneumatometry (average 3 readings) Portable applanation (perkins) Dynamic Contour Tonometer DCT (not affected by rigidity) Ocular Response Analyzer ORA (pneumatometer, hysteresis) Electronic appl/inden (Toonopen) (distorted odematous cornea) Identation (schoitz) Implantable tonometer!
- 7. IOP • Decrease: exercise, parasympathomimetic (miotics), pregnancy. • Increase: morning (diurinal variation), CVP in valsalva, eye movement in restrictive myopathy. • Inter eye assymmetry > 3-5mmHg. (risk factor). • Diurinal IOP flactuation > 2-5mmHg (risk factor).
- 8. Gonioscopy Gonioscopy Indirect Goldmann Coupling agent. Stabilize globe. Pressure ... Narrow angle. Zeiss (indentation) No coupling agent (better visualization). Pressure … wide angle. Differentiate synechia from narrow angle. Direct Koeppe Diagnostic, therapeutic.
- 10. Gonioscopy Angle structure evaluation clinically 1. Schwalbe line, SL 2. Trabecular meshwork, TM 3. Scleral spur, SS 4. Ciliary body, CB 5. Iris process
- 11. Gonioscopy
- 12. Gonioscopy Angle structure evaluation clinically Shaffer classification: • Grade 4 (40): CB seen. • Grade 3 (30): SS seen. • Grade 2 (20): TM seen. • Grade 1 (10): SL seen. • Grade 0 (closed): iridocorneal contact
- 13. Gonioscopy 1. Angle structure evaluation clinically 2. Assess structures: TM pigmentation: • PEX, PDS • Iritis • Glaucoma (post ACG) • Melanosis • Endocrine • Naevus (cogan reese $) • Trauma Blood in SC: • CCF • Sturge weber $ • SVC obstruction • Hypotony • Post gonioscopy
- 14. Gonioscopy Angle evaluation clinically Van Herick method: • Normally AC depth = corneal thickness. • Shallow AC < 1/4 corneal thickness.
- 15. Disc
- 16. Disc 1. Size 2. Shape 3. Colour 4. Borders 5. C/D (vertical), pallor, cup = pallor? 6. NRR, ISNT rule 7. Peripapillary area (Alpha and Beta zones) 8. RNFL assessment 9. Disc surface (hge, collateral, lesion) 10. Other eye
- 17. Disc 1. Size • 1.5- 1.7 mm • Large in myopia, black race (risk factor toNTG) • smaller in hyper metropia
- 18. Disc 2. Shape • Round, slightly oval (V > H). • Other Variation: Tilted D shaped in astigmatism, high myopia. • Tilted disc in VF .. Superotemporal VF defect.
- 19. Disc 3. colour • NRR … pinkish • Scleral ring, lamina cribrosa … white
- 20. Disc 4. Borders • Well defined • Sharply defined … end stage glaucoma
- 21. Disc 5. C/D • Vertical that is considered • At the site of bl vs change of direction (kinking, bending) • > 0.2 difference between both eyes … pathological • Large disc … large cup & the reverse • 2% have C/D 0.7
- 22. Disc 5. C/D • Cupping > pallor ... glaucomatous • Pallor > cupping … neurological
- 23. Disc 6. NRR • ISNT rule (high sensitivity, low specificity) (مش جلوكوما عيان كل لكن بيحترمه جلوكوما عنده مش عيان كل مش هيحترمه)
- 24. Disc 7. Peripapillary area • Alpha & Beta zone (low sensitivity, high specificity) (يبقى موجود مش بيكون عيان كل ومش عنده بيكون جلوكوما عيان كل مش جلوكوما مش)
- 25. Disc 8. RNFL assessment • Exam with red free filter (defect)
- 26. Disc 9. Disc surface • Hge, NVD, collaterals, lesion
- 27. Disc 10. Other eye • C/D? • Uni/ Bi lateral?
- 28. Disc changes in glaucoma 1. C/D increase with > 0.2 asymmetry ( cupping > pallor) 2. NRR inferior notch, ISNT rule --- highly sensitivite but not specific (كل مش جلوكوما عنده مش عيانهيحترمه مش جلوكوما عيان كل لكن بيحترمه) 3. Baring of bl vs (space between NRR & bl vs) 4. Bayoneting of bl vs (double angulation) 5. Peripapillary area PPA (Alpha and Beta zones (عيان كل مش مش بيكون عيان كل ومش عنده بيكون جلوكوماموجودجلوكوما مش يبقى) ) 6. RNFL thinning 7. Lamina dot sign 8. Disc hge
- 29. Glaucomatous disc changes 1. C/D ratio asymmetry > 0.2
- 30. Glaucomatous disc changes 2. NRR inferior notch, ISNT rule #
- 31. Glaucomatous disc changes 3. Baring of b v (early NFL thinning) Space between NRR and small b v In early glaucoma
- 32. Glaucomatous disc changes 4. Bayoneting of b v Double angulation of b v
- 33. Glaucomatous disc changes 5. PPA (Alpha and Beta zone) Low sensitivity, high specificity
- 34. Glaucomatous disc changes 6. RNFL thinning In early glaucoma Value of OCT In glaucoma, neurological dis, normal individuals
- 35. Glaucomatous disc changes 7. Lamina dot sign Grey dot like fenestration (lamina distortion) In advanced stage
- 36. Glaucomatous disc changes 8. Disc hge Flame shaped In NTG, retinal vascular dis, normal person
- 37. Normal visual field (Standard Automated Perimetry SAP) • Our vertical range 120° verically & 160° horizontally • SMIL from point of fixation (60° superiorly, 60° medially, 70° inferiorly, 100° laterally) • Peak at fixation then decrease suddenly 10° around fixation then gradually at periphery (3D dimentional hill) • At 10-15° nasal (temporal in VF) to fixation ON head … (Normal Absolute scotoma)
- 38. Definitions in visual feild • Isopter (line of connecting points of the same intensity). • Threshold (least intensity of stimulus at fixed location seen in 50% of occasions). • Scotoma (relative scotoma means decrease sensitivity, absolute scotoma means lost sensitivity). • Decibel concentrate on eye sensitivity more than stimulus intensity (ie; more db, more eye sensitivity). العين استجابة • Apsotilbs concentrate on luminance, stimulus intensity (ie; more asb , less sensitivity). رِثالمؤ قوة
- 39. Perimetry • Confrontation. • Amsler chart. • Manual (Tangent screen), or Automated (Humphery). • Static (Humphery, Octopus), or Kinetic (Goldmann, Tangent screen). Stimulus (intensity) • Size • Brightness • Motion • Background Field (sensitivity) • Intact retinal &neuronal pathway • Limitation (lid, nasal bridge, supraorbital ridge)
- 40. Humphery perimetry analysis How to read and comment on? Precautions: • Pupil not < 3mm (decrease sensitivity).. In repeated field? • Refractive error (decrease contrast). • Reading glasses > 40y . • Spectacle for hyperopia enlarge scotoma …. CL. • Spectacle frame ( narrow rim ). • Ptosis, media opacity, retinal adaptation after ophthalmoscopy
- 42. Humphery perimetry, How to read and comment on? 1. Type of test, pattern, algorihm (eg. humphery, SITA, 24-2), Name, date, age.
- 45. Humphery perimetry • Type (automated, static) • Test algorithms -Threshold. -Suprathrshold …. For screening -SITA (Sweddish Interactive Threshold Algorism) …. less time without losing accuracy. -FDT (Frequency Doubling Technique) …. Test magnocellular for early glaucoma. -SWAP (Short Wavelength Automated Perimetry) … blue yellow for early glaucoma. • Test patterns - (24-2), (30-1), (30-2), (10-2)…. 1st number for tested area around fixation, 2nd number for test at both sides of meridian.
- 46. Normal visual field (Standard Automated Perimetry SAP) • GCC (Ganglion Cell Complex) early glaucoma damage then NFL • SAP … SWAP (Short Wavelength Automated Perimetry, FDT (Frequency Doubling Technology) • GCC Parvocellular (color, form) Magnocellular (flicker, motion) Koniocellular (short WL blue)
- 48. 3. Reliability indices < 25% • Fixation loss (stimulus in blind spot) • False positive (happy flicker) • False negative (-ve with brighter stimulus) Clover leaf pattern (false negative)
- 51. 4. Global indices • Mean Deviation MD (average deviation at each point from age corrected normal) generalized depression Minus value is bad 1. -2 to -6 … mild 2. -6 to -12 … moderate 3. > -12 … severe
- 52. 4. Global indices • Corrected Pattern standard Deviation PSD = PD (corrected by short term fluctuation)
- 56. 5. Sensitivity values Grey scale • Dark tones … (low sensitivity) • Blind spot … (temporal just inf. To horizontal axis)
- 58. 5. Sensitivity values Total Deviation TD • Deviation of sensitivity at each point from normal (corrected with normal age values). • Negative (lower sensity than normal), positive (higher than normal) corrected with normal age values. • Generalized defect.
- 60. 5. Sensitivity values Pattern Deviation PD • Total deviation values adjusted for any generalized decreased sensitivity. • Localized defect.
- 62. 5. Sensitivity values Probability value blots • Probability values (percentage of abnormal values present in normal persons) in TD, PD • The lower p value, the more probability to be abnormal. • <5% to < 0.5%
- 63. Tracking to assess pt fixation
- 64. Glaucomatous changes in visual feild • Central, paracentral defect
- 65. Glaucomatous changes in visual feild • Central, paracentral defect • Nasal step
- 66. Glaucomatous changes in visual feild • Central, paracentral defect • Nasal step • Temporal wedge
- 67. Glaucomatous changes in visual feild • Central, paracentral defect • Nasal step • Temporal wedge • Seidel scotoma, arcuate, double arcuate
- 68. Glaucomatous changes in visual feild • Central, paracentral defect • Nasal step • Seidel scotoma (extending from blind spot) • Seildel scotoma, arcuate, double arcuate • Tunnel vision
- 69. Glaucomatous changes in visual feild
- 70. Glaucomatous changes in visual feild