Effect of Alphagan on Retinal Blood Flow Autoregulation and Motion Detection in Patients With Normal Pressure Glaucoma
| Status: | Recruiting |
|---|---|
| Conditions: | Ocular |
| Therapuetic Areas: | Ophthalmology |
| Healthy: | No |
| Age Range: | Any |
| Updated: | 2/4/2013 |
| Start Date: | March 2010 |
| Contact: | Louis R Pasquale, MD |
| Email: | Louis_Pasquale@meei.harvard.edu |
| Phone: | 617-573-4270 |
Effect of Brimonidine 0.15% on Retinal Blood Flow Autoregulation and Motion Detection in Patients With Normal Tension Glaucoma
The investigators have completed a study in which the investigators examined the response of
the retinal circulation to changes in posture from sitting to lying down in patients with
Normal Tension Glaucoma (NTG). This alteration in position produces changes in the local
blood pressure at the entrance to the retinal vasculature. In a healthy retina, the
vasculature adapts by dilating and constricting in order to maintain a steady blood flow
rate. In an eye with NTG, this often does not occur. Upon analysis at the completion of
the study , the investigators found that the patients who had been taking Alphagan
(brimonidine) during the study did not exhibit the blood flow increases typical of NTG while
lying down; instead, they maintained a steady blood flow rate as did the group of healthy
control subjects. The investigators primary objective is to now demonstrate in a
prospective study that Alphagan can restore retinal vascular autoregulatory function in
patients with NTG who do not autoregulate. The investigators will also determine the effect
of Alphagan treatment on the patients' ability to detect motion.
Inclusion Criteria:
- Eligible subjects will have no history of IOP > 24 mm Hg in either eye.
- All subjects will have open angles on gonioscopy with the filtering portion of the
trabecular meshwork visible for 360° in both eyes.
- Previously or newly diagnosed patient are required to have HVFs that are reliable and
show loss consistent with nerve fiber layer atrophy.
- Patients with glaucoma-like discs (CDR>0.7 in either eye) and normal/reliable visual
fields who the PI has opted to observe without treatment will enter the study if they
meet the other study criteria.
- In order to facilitate the retinal blood flow measurements, only subjects with
refractive error within the range -10 to +10 diopters, no lens opacities greater than
1+ cortical spokes or 2+ nuclear sclerosis, and pupillary dilation of at least 6 mm
following mydriasis will be included.
Exclusion Criteria:
- Patients with evidence of exfoliation or pigment dispersion syndrome in either eye.
- Patients with a cup/disc ratio > 0.8.
- Known history of allergy to brimonidine.
- Patients already on treatment with brimonidine will be excluded from the study.
- Diabetic retinopathy.
- History of ocular laser or incisional surgery in either eye.
- Use of systemic alpha-2 blockers.
- Pregnant or planning to become pregnant.
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