Variability in Perimetry Study

Disease of the optic nerve, including glaucoma, is the leading cause of blindness in the
United States. Treatment decisions for optic nerve diseases are based largely on the changes
in visual function that occur mostly as a consequence of disease progression. Unfortunately,
the decision as to whether change of visual function has occurred is often difficult because
of the high retest variability of conventional visual field testing (perimetry). This
variability is so high that with moderate visual loss, a minimum of six tests are often
needed in patients with optic nerve damage to reliably distinguish visual field
deterioration from random variation. The preliminary data show that a substantial portion of
the variability of perimetry lies in the type of stimulus used and the testing strategy
applied.

OBJECTIVES: The investigators propose to test the hypothesis that a large portion of total
perimetric variability in patients with visual loss is due to a poor signal-to-noise ratio
associated with using a small fixed-size stimulus.

RESEARCH PLAN AND METHODS: To test this hypothesis, the investigators are examining patients
with optic nerve diseases with conventional automated perimetry (size III) and tests having
large-sized and scaled stimuli (size V, size VI (custom perimeter) and luminance size
threshold perimetry - a test where threshold is found by changing stimulus size rather than
stimulus intensity). Over four years the investigators will test 100 patients with and
glaucoma and 60 normals each eight times. In addition, the investigators are retesting 50
subjects once a week for 5 weeks. The investigators are also studying the associated
structural-functional correlations using OCT and developing a statistical model that
accounts for correlations of neighboring test locations.

Perimetric variability and the reliable identification of visual field change is the single
most difficult problem in visual testing today. The investigators anticipate identifying a
method that allows efficient and accurate determination of visual field change.
Identification of a superior method would (1) reduce the number of examinations needed,
thereby reducing the costs of medical care; (2) minimize misdiagnosis, unnecessary testing
and even unnecessary surgery that results from mistakenly interpreting fluctuation of the
visual field as progression or improvement; (3) allow earlier disease intervention and (4)
reduce the costs of clinical trials.

Inclusion Criteria:

- Mean deviation of -20 or better with 5-8 points (optimally 10 points) with a value of
p= 0.05 or better on the total deviation plot

- Mild cataract with VA of 20/30 or better pinholed

- Refractive error of = to or less than 6 diopters with = or less than 3.50 diopters of
cylinder

- Pupil diameter of 3 mm minimum

- Controlled hypertension, diabetes, migraine

- Pseudophakic/refractive surgery if no vision problems

- Trabeculectomy okay if will progress

Exclusion Criteria:

- History of other ocular or neurologic disease or surgery

- History of stroke

- Systemic disease [lupus, graves, cancer (within the last 5 yrs), AIDS, other]

- History of amblyopia

- Unreliable patient

- Frequently misses appointments

- Tests poorly

- Ocular hypertension

- Retinal problems

- Diabetic retinopathy

- Neurological disease (IIH, ON, AION)

- Cancer not in remission for the last 5 years

- Vein or artery occlusions

- Macular degeneration

- Trauma with vision loss

- Ocular inflammation (pars planitis, iritis, temporal aeuritis)