1. Diagnostic Considerations in Contemporary Glaucoma Management COPE - 46913-GL
C. Lievens, OD MS FAAO

2. US Glaucoma Statistics
One of the leading causes of blindness in the US
Over 4 million Americans have glaucoma
50% do not know they have it
Approximately 5-10 million have elevated IOP
Glaucoma ophthalmic drug therapy in 2011 was $3B
By 2050, rate of glaucoma expected to triple
US regions most likely: South & Southwest

3. Impact of Glaucoma What is the impact of vision loss (Va <20/40)?
Increased risk of falls
Hip fractures
Depression
Loss of social independence
Reference
1. Taylor HR. LXIII Edward Jackson Memorial Lecture: Eye care: dollars and sense. Am J Ophthalmol. 2007;143:1-8.
Taylor HR. Am J Ophthalmol. 2007;143:1-8.

4. Purpose of VF Testing
To quantify functional ability in terms of the weakest spot of light (visual stimulus) that can be seen at representative locations in the visual field.
Many factors need to be considered in the process.

5. Diagnostic Tests Gonioscopy 92020 Threshold Perimetry 92083
Ophthalmoscopy (Ext /6)
Tonometry
Random test
Serial/diurnal measurement 92100
HRT/GdX/OCT/Talia/Optoview/etc. (ONH) 92133
Pachymetry 76514
Fundus Photography (ONH)

6. Visual Field Testing

7. What are we trying to measure with static perimetric testing?

8. Factors that Influence VF measurement

9. The “normal” visual field will vary for a given individual and between individuals
Contrast between object and background
VF testing is simply a measure of CSF
Age
Miosis
Media clarity
Uncorrected refractive error
Perimetrist (not as much of a factor in automated testing, but worth the investment of training your staff!)

10. PERIMETRIST Important variable when considering results
Prior to mid 80’s – performed manually by technicians
perimetrist and patient variability
Standardized Automated Perimetry (SAP)
Eliminated some technician bias
BUT still room for improvement
“ the single most fertile areas for improving clinical perimetry – the management of and training of patients and technical staff.
- Heiijl, et al (2012)

11. Released October 2012
“…Chapter 2 is particularly important because it explains how the perimetrist can improve test results even when using a highly automated instrument. The perimetrist should not simply stand by and watch the test, but should perform the test using the instrument….”
Douglas R. Anderson, MD, FARVO
Professor Emeritus
Bascom Palmer Eye Institute

12. Patient Factors Age Attention Speed of reaction
Understanding of test procedures
Fixation
Learning Effects
All factors must be considered when choosing a visual field testing strategy

13. Interpretation of the VF results
Correct interpretation of the results must analyze the field in terms of:
Reliability
Visual defect present
Size and shape
Location
Density
Repeatability

14. What are we trying to evaluate?
GLAUCOMA
NEUROLOGICAL CONDITIONS
RETINAL DISORDERS
OTHER

15. Review of landmark study results

16. AGIS AGIS (Advanced Glaucoma Intervention Study) 591 pts, 789 eyes
Known pts with unstable VF and/or ONH’s
Randomized trial to compare
laser first
surgery first
Main result: No difference

17. AGIS cont.
Important finding: Eyes with 100% of visits with IOP <18mmHg over 6 years had a VF defect score (from baseline) close to zero
Important finding: Eyes with 50% of visits with IOP <18mmHg over 6 years showed VF progression

18. AGIS cont. IOP 18mmHg slowed progression
15mmHg showed ½ the progression of 18mmHg
13mmHg showed ½ the progression of 15mmHg
Diurnals Important!
Avg IOP = 15mmHg
Curve progresses less than 11-19

19. CIGTS (Collaborative Initial Glaucoma Treatment Study)
607 newly dx’ed pts
Randomized to medical tx or trab.
Medical IOP lowering of 35%
Surgical IOP lowering of 47%
VF is primary outcome observed
5-year outcome: No difference in patient quality of life

20. CNTGS (Collaborative Normal Tension Glaucoma Study)
145 eyes randomized
Observation or 30% IOP lowering
Using any drops, ALT, or trab
10 IOP readings – none>24mmHg
Outcome
80% observation group progressed at 5 years
40% treated eyes progressed at 5 years

21. EMGT (Early Manifest Glaucoma Trial)
Compare effect of:
IOP tx
NO tx
Delayed tx
50-80 y/o’s
POAG, NTG, Exfoliative
Mild to moderate VF defects
IOP > 30 or severe VF defects excluded

22. EMGT cont. 255 new patients Randomized to: 3mo f/u for 10 years
ALT
Betoptic
Observation
3mo f/u for 10 years
IOP reduced by average of 25% in treatment groups

23. EMGT cont. 45% progressed in tx groups
62% progressed in observation group
Tx group 66 months
Observe group 48 months
Each 1mm of decrease related to 10% decrease of risk of progression

24. OHTS (Ocular Hypertension Treatment Study)
Prospective study, y/o’s
1636 patients randomized to 20% IOP lowering/24mmHg or observation
IOP between 21-32
Normal SLE, ONH’s, VF
50% treated

25. OHTS cont.
Results
Lowering IOP by 20% reduces risk by 50% over 5 years
Need to treat 100 people per year to prevent 1 from getting GLC

26. OHTS cont. Risk Factors identified Age: 22% increased risk per decade
Race (African-American)
Higher initial IOP: 10% increased risk per 1mmHg
Thinner corneas
Larger C/D’s: 32% increased risk with 0.1 increase
Heart disease

27. Pachymetry Can be billed ONE TIME
36% of pts with IOP>25.75 & CCT<555 dx GLC
6% pf pts with IOP>25.75 & CCT>588 dx GLC
15% of pts with C/D .3rnd & CCT<555 dx GLC
4% of pts with C/D .3rnd & CCT >588 dx GLC

28. Corneal Thickness
Take great care in using “pachymetry/IOP correction tables”
OHTN Patients with thin corneas (<555 microns) were found to have a significantly greater risk of developing glaucoma then those with thick corneas (>588 microns )

29. CCT
Powerful Predictor for the development of POAG Relative risk of POAG increased 81% for every 40µ thinner

30. Visual Field Analysis

31. Navigating the
Print Map

32. The Visual Field Printout
What does it tell you??
1.) I.D. of patient and test
2.) Test Reliability
3.) Unprocessed Threshold Sensitivity
4.) Total Deviation-Measured v. Norm
5.) Pattern Deviation-Norm v. Pt performance after adjustment for overall sensitivity change
6.) Global Indices
7.) Gaze Tracking
8.) GHT – Plain Language Analysis

33. Raw Data Threshold points are plotted in db
Normal central values will range around 30db
‘0’ means that a point was seen only at the brightest intensity
Point not seen is marked ‘<0’

34. Gray scale Provides an approximate picture of the field.
This should not be used in the analysis of the field

35. HFA Specific Reliablility indices
Found in the upper left hand corner of the printout
Fixation losses : FL
False positive errors: FP
False negative errors: FN

36. False positive
Refers to the number of times a patient responds and no target is presented.
Flagged if it exceeds 33%
May be a sign of a “trigger happy” patient and will artificially improve the VF

37. False Negative
Refers to the number of times a patient fails to respond to a suprathreshold target placed in a seeing area of the visual field.
Flagged if it exceeds 33%

38. Total Deviation Plot (db)
Appears as numbers and graphic in the central left area of printout
Represents the difference between the measured threshold of each individual test location and the age-corrected normal value for that location

39. Pattern Deviation Plot (db)
Takes the Total Deviation plot and adjusts it upwards or downwards to screen out generalized depression

40. Probability Plots (p value)
Found in between gray scale of total deviation and pattern deviation plots
Indicates how frequently a total or pattern deviation value at a particular test location is found in the normal population

41. Global indices Found on the lower right hand corner of the printout
Visual Field Index (VFI)
Mean deviation (MD)
Pattern standard deviation (PSD)

42. Visual Field Index
Recently developed staging index to assist in separating changes in overall depression of field due to media opacity.
Provides improved correspondence to ganglion cell loss compared to Mean Deviation alone.
RANGE
100% (normal) to 0% perimetrically blind eyes

43. Mean Deviation (MD)
Average departure (+ or -) of each test location from the age-corrected normal value
Can be affected by overall depression as well as significant loss in one part of the field.

44. Pattern Standard Deviation (PSD)
Measures the extent to which the threshold determinants at different locations differ from each other
Very significant indicator of field abnormality, especially if p < 5%

45. Interpretation of the Global Indices
Mean Deviation
PSD
Interpretation
Normal
Visual Field probably normal
Abnormal
Generalized loss of sensitivity
Small localized defect
Large defect with a localized component

46. Pharmacology comparison
XLT Study: (Xalatan vs. Lumigan vs. Travatan)
Summary
No racial difference between racial groups were noted
Subjective
Fewer patients had claims of ocular hyperemia with latanaprost (researchers agreed)
Note subsequent study agreed and added the same conclusion with eyelash growth

47. Pharmacology comparison
Ocular and systemic side effects of Alphagan .2% in children
There have been occasional reports of systemic adverse effects in children including apparent central nervous system depression. There are few data available on the overall safety of brimonidine 0.2% in children.
In this study, 18% of children had systemic adverse effects sufficient to necessitate stopping the drug

48. Alphagan P in Peds??? Still NOT recommended
Report severe breathing problems with use in children under age 2
Take caution

49. Severity of Glaucoma Mild Moderate Severe
characteristic optic nerve abnormalities are consistent with glaucoma, but there is a normal visual field.
Moderate
visual field abnormalities are in one hemifield and not within 5 degrees of fixation.
Severe
visual field abnormalities are in both hemifields or loss is within 5 degrees of fixation.

50. Glaucomatous optic nerve changes
Asymmetric C/D ratios
Optic cupping
Vertical cup elongation
Notching / temporal unfolding
Shifting of disc vessels
Saucerization of the cup
Bean-potting
Visible lamina
Optic nerve collateral development
Peripapillary atrophy
Neuroretinal rim loss
Optic disc hemorrhages
Nerve fiber layer loss
Cup-pallor discrepancy

51. Targeting IOP Cookbook Initial target: reduce by 20-30%
From highest IOP
Mild GLC 20-30%
Moderate GLC 30-40%
Severe GLC %

52. Patterns and Progression
Glaucomatous VF Loss
Patterns and Progression

53. Patterns of Visual Field Loss
Glaucomatous
VF Loss
Generalized
Depression
Diffuse loss
of retinal sensitivity
Increased variability
Asymmetric
superior/inferior VF
Focal VF Loss
Arcuate scotoma or
Bjerrum scotoma
Altitudinal defect
Paracentral scotoma
Early and Later
Nasal Step
Patterns of Visual Field Loss

54. Loss of Temporal Island
Glaucomatous
VF Loss
Generalized
Focal/Localized
Early defects
Late Defects
ADVANCED VF LOSS
Central Field with
Temporal Island
Splitting of Fixation
Loss of Central Field
Loss of Temporal Island
Patterns of Advancing Focal Visual Field Loss

55. Location, Location, Location
63% above horizontal
7% show initial field defects outside 30° with normal central fields
Optic Nerve Evaluation in key!
With analysis of risk factors,
IOP and CCT

56. Analysis of the VF Print-out
Comparison analysis can identify the earliest generalized depressions
Inter-eye differences:
MD, quadrant dB
Hemifield comparison:
point to point on horizontal midline
Multiple field symmetry:
point to point between tests

57. Improving Compliance
G. Swartz, Improving Patient’s Adherence to Glaucoma Therapy, Glaucoma Today, Spring 2011,

58. Glaucoma Adherence & Persistance Study (GAPS)
N=~14K
Pharmacy claims data
Patient chart review
Doctor interviews
Patient interviews

59. Common barriers to compliance:
Concern about side effects (67%)
Difficulty with eye drops (36%)
Cost (25%)

60. Factors associated with nonadherence
Does not connect nonadherence with vision loss
Exclusive dependence on the doctor for information and education
Cost
Race
Sampling

61. Recommendations

62. Ask questions effectively
Non-judgemental
Inquire about difficulties
Cost
Running out
Side effects
Forgetfulness
Drop adminstration

63. Find out what patients know
Ask patients to state their understanding of glaucoma and the benefit of using drops

64. Learn about missed doses
Ask patients how many times per week or month they have missed their medications
Simplify the dosing regimen as much as possible
Link the dosing whenever possible to a daily part of a routine
Be sensitive to economics

65. This study shows that in a group of stable open angle glaucoma patients, the addition of home tonometry performed using Proview as an adjunct to their IOP lowering medication did not have any significant effect on the amount of medication used, thus compliance was not significantly affected.

66. Why?
First, using once-a-day medications patients may already at the maximum state of compliance by their very nature.
The addition of Proview usage could have distracted a percentage of them in the same way that an additional medication would.

67. Why?
Secondly, “good” Proview readings may have lured them into a false sense of security.
Patients may have consciously decided to halt their medications on “good” IOP days.
all patients were aware of their target IOP

68. Interobserver Reliability

69. Interobserver error is of concern
Even with experts, the vertical C/D measure has been proposed to lack clinical usefulness (with differences of 0.2 disk diameters (DD) or more between individual observers being commonplace).

70. Optometry
Research has found glaucoma trained fellows to be superior in grading C/D ratios as compared to optometry and general ophthalmology.
Specifically interobserver agreement in estimating C/D was significantly higher for GLC Fellows when compared to optometrists, residents, and general ophthalmologists

71. Why?
It has been reported that 41% of surveyed eye care practitioners have no method that they consciously use to gauge C/D ratios, except experienced estimation.

72. Results
The use of our card places both optometrists and interns in the substantial agreement category (as were glaucoma specialists)