Transcript Visual Field Progression: Differences Between Normal

Visual Field Progression: Differences
Between Normal-Tension and
Exfoliative High-Tension Glaucoma
KG Ahrlich,1,3 CGV De Moraes,2 CC Teng,2 TS
Prata,2 R Ritch,2 JM Liebmann1,2
1New
2Einhorn
York University School of Medicine, New York, NY
Clinical Research Center, New York Eye & Ear Infirmary, New York, NY
3Manhattan Eye, Ear, and Throat Hospital, New York, NY
Supported by the ASCRS Foundation and the Ephraim and Catherine Gildor
Research Fund of the New York Glaucoma Research Institute.
The authors have no financial interest in the subject matter of this poster.
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Introduction
• The relative importance of IOP-dependent and IOP-independent
risk factors varies among individuals and forms of glaucoma.
• Exfoliative glaucoma (XFG) is characteristically associated with
elevated IOP (exfoliative high tension glaucoma, XHTG), and IOPdependent factors are thought to play a central role in disease
onset and progression.
• Glaucomatous eyes with an IOP in the statistically normal range
(normal-tension glaucoma, NTG) are less dependent on IOP for
disease onset and progression.
• It remains unclear whether the same pattern and rates of
glaucomatous visual field deterioration are present in both NTG and
XHTG.1-8
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Purpose
• To compare the pattern, location, and rate of
visual field (VF) loss in NTG and XHTG.
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Methods
• The Glaucoma Progression Study (GAPS) consists of 43,660 consecutive
subjects (132,512 VF tests) evaluated in a glaucoma referral practice
from January 1999 to December 2008.
• Subjects with glaucomatous optic neuropathy, repeatable VF loss, ≥5
SITA-Standard VF examinations, and NTG or HTG, were enrolled. If both
eyes were eligible, one was selected randomly.
• NTG was defined as glaucomatous VF loss and all known IOP
measurements ≤21 mmHg.
• HTG was limited to exfoliative glaucoma (XFG), defined as
glaucomatous VF loss, untreated IOP >21 mmHg, and the presence of
exfoliation material on the pupillary margin and/or on the anterior lens
capsule.
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Methods
• VISUAL FIELD ANALYSIS
• Automated pointwise linear regression (PLR) analysis was
performed using Progressor™ (Version 3.3, Medisoft, Inc., London,
UK), providing slopes (decibels [dB]/year) of progression globally and
locally for each point based on threshold maps, as well as
significance (p-values).
• The number and location of the significantly progressing points was
compared with the division of VF sectors described by Garway-Heath
et al.9 This information was used to establish the most common
location of progressing points in each group.
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Methods
• CLINICAL DATA
• Baseline central VF loss was defined by the presence of at least one
point with p<0.01 within the four central-most points of the pattern
deviation graph in the two consecutive baseline tests.
• Progression was defined as the presence of a test point with a
slope of sensitivity over time >1 dB loss/year, with p<0.01. For edge
points, a stricter slope criterion of >2 dB loss/year (also with p<0.01)
was used.
• Paracentral progression was defined as progression of any of the
points adjacent to the four central-most points of the VF (i.e.,
within the 12 central-most points).
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Results
Table 1. Baseline characteristics of the studied population.
NTG (n=139)
XHTG (n=154) P-value
Age (years)
62.7 ± 12.8
72.6 ± 9.4
<0.01
Gender (women)
92 (66.1%)
88 (57.1%)
0.14
Ethnicity (European ancestry)
106 (76.2%)
144 (93.5%)
<0.01
Migraine/Raynaud’s/Hypotension
53 (38%)
6 (4%)
<0.01
Cardiovascular diseases*
59 (42%)
86 (56%)
0.02
Mean number of VF
8.2 ± 3.5
8.1 ±2.9
0.78
Mean follow-up time (years)
5.2 ± 2.0
5.6 ± 1.8
0.07
Baseline mean deviation (dB)
-6.5 ± 5.4
-6.7 ± 7.0
0.78
Central defect at baseline VF
82 (58.9%)
49 (31.8%)
<0.01
CCT (µm)
533.9 ± 35.9
544.0 ± 35.7
0.01
Mean follow-up IOP (mm Hg)
13.3 ± 2.0
16.5 ± 3.2
<0.01
VF=visual field, NTG=normal-tension glaucoma, XHTG=exfoliative high-tension glaucoma,
CCT=central corneal thickness, IOP=intraocular pressure.
*Includes: hypertension, coronary ischemia, stroke.
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Results
Table 2. Intercurrent characteristics of the studied population.
NTG (n=139)
XHTG (n=154) P-value
Endpoint of progression
64 (46%)
75 (48.7%)
0.73
Mean follow-up time of progressing eyes
(days)
2102 ± 590
2087 ± 587
0.88
Progression at or adjacent to central VF
48/64 (75%)
43/75 (57.3%) 0.04
Global rate of change1 (dB loss/year)
-0.46 ± 0.6
-0.58 ± 0.7
0.20
Localized rate of change1 (progressing
points) (dB loss/year)
-2.0 ± 2.2
-2.8 ± 2.1
0.08
Mean number of progressing points in
the VF
3.7 ± 8.3
5.5 ± 8.1
0.35
VF=visual field, NTG=normal-tension glaucoma, XHTG=exfoliative high-tension glaucoma,
CCT=central corneal thickness, IOP=intraocular pressure.
1Values
are adjusted for differences in age, CCT, and mean IOP between groups.
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Results
Figure. Mapping of the location of significant visual progression in glaucomatous eyes
that reached a progression endpoint (modified from Garway-Heath et al.9 Significant
progression was defined by any test point with a slope >1.0 dB loss/year with p<0.01 (or
>2.0 db loss/year for edge points). A, NTG; B, XHTG.
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Discussion
 We optimized the evaluation of the velocity and pattern of VF
progression associated with IOP by comparing a group of patients
with non-IOP-dependent factors (NTG) and one in which IOP is
believed to play a predominant role (XHTG).
 XHTG and NTG eyes progress at a similar global rate after
adjustment for differences in CCT, IOP, and age. However, NTG eyes
progress more often in the central field, independent of other
factors.
 The most important factor associated with paracentral progression
among eyes that reached a progression endpoint was the diagnosis
of NTG.
 The results of our analysis of VF progression correlate well with
previous studies of NTG and XHTG, despite our use of trend analysis
by PLR.10,11
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Conclusion
• NTG eyes tended to show a faster progression rate in the central
field, but rates of global VF loss are similar between treated NTG
and XHTG patients.
• Greater surveillance of the central field in NTG may be warranted,
with more widespread use of alternative methods to follow NTG
patients, including:
• visual field strategies assessing the central ten degrees
• multifocal visual evoked potential techniques
• microperimetry
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