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EFFICACY

Januleviciene et al

two including impaired autoregulation within the OAG pop- MATERIALS AND METHODS
ulation (4). Liu et al (5) showed that abnormal hemodynam-
ics can affect the blood supply to the optic disc and retina Thirty patients with OAG were recruited for a 1-year study.
in primary OAG (POAG). Visual field damage progression We performed a prospective, randomized, double masked,
further correlated with retrobulbar hemodynamic variables, parallel study. All subjects read and signed an informed
independent of the extent of glaucomatous damage and consent, and the study was approved by Kaunas University
intraocular pressure (6). of Medicine’s institutional review board. The study eye was
Although we have growing evidence to suggest that pa- chosen randomly. Glaucoma was defined by characteristic
tients with glaucoma have reduced blood flow to the retina, glaucomatous visual field loss, optic nerve head damage,
choroid, and optic nerve, we do not have clear evidence and IOP greater than or equal to 21 mmHg, as determined
on the clinical relevance of these finding in terms of visual by Goldmann applanation tonometry without treatment
function. Visual field testing is considered to be the gold (14). Included were patients with OAG over 18 years old
standard for glaucoma diagnosis and follow-up, but it has who were willing to sign an informed consent statement
distinct limitations. Histologic studies have found that as and able to comply with the requirements of the examina-
many as half of all ganglion cells can be lost before a de- tions. Visual acuity requirements included best-corrected
fect is detected by the visual field (7). Furthermore, visual visual acuity of 0.5 or better. Exclusion criteria included
field examinations have a high variability of results. Almost mean deviation greater than or equal to –12 dB in Hum-
86% of the defects detected with standard automated pe- phrey visual field central 30-2. We also excluded patients
rimetry are not replicated on repeated testing (8). with cup to disc ratio equal to or greater than 0.9, history
One of the major hallmarks of glaucoma is loss in retinal of eye disease other than refractive error, orbital or ocular
ganglion cells and as a consequence loss in nerve fiber trauma, and history of renal or hepatic disease, asthma, or
layers. Apoptosis of retinal ganglion cells has been con- respiratory disease, or allergy to either of the study medi-
sidered the most plausible pathogenic mechanism of glau- cations. Pregnant or nursing women were excluded.
coma. Apoptosis can be caused by neurotrophic factor Patients were instructed to avoid caffeine intake, smoking, and
withdrawal or glutamate release and both are triggered exercise for 3 hours prior to each study visit. All study visits were
by elevated IOP and ischemia, simultaneously or sepa- scheduled at the same time of day ±1 hour in order to avoid di-
rately (9). Nerve fiber layer (NFL) thinning was reported to urnal fluctuations in IOP and arterial blood pressure (BP).
precede visual function loss and optic disc changes (10, Patients were given timolol bid for 4 weeks run-in period
11). Scanning laser polarimetry is one of the techniques before study entry. After 4 weeks of timolol treatment, we
to measure peripapillary NFL thickness. Evaluation of the randomly assigned patients to treatment Group A or B (15
retinal NFL (RNFL) may facilitate and support the clinical patients in each group): Group A received topical treatment
course of glaucoma. with DTFC bid (morning and bedtime) while Group B re-
Multiple IOP lowering medications are frequently required to ceived topical treatment with LTFC qid (morning time).
achieve adequate control of IOP. Fixed combination treat- Examinations were carried out at baseline and at 1, 6, and
ments provide effective IOP control with the advantages 12 months of treatment. Each study visit included adverse
of improved patient compliance and without the washout events check, BP measurements with a calibrated mercury
effect of multiple drops (12). Vorwerk et al (13) suggested sphygmomanometer, and radial pulse rate measurements
that treatment alterations are necessary to achieve suffi- taken by palpation for a 60-second time interval. Ocular
cient IOP control. By prescribing more aggressive thera- perfusion (OP) was calculated as 2/3 of mean arterial blood
pies as outlined by treatment guidelines, including fixed pressure minus IOP; diastolic perfusion pressure (DPP) was
combination preparations, both efficacy and compliance calculated as diastolic blood pressure minus IOP; systolic
of the patients may be improved. perfusion pressure (SPP) was calculated as systolic blood
The aim of our study was to compare IOP-lowering ef- pressure minus IOP (15).
fect of latanoprost/timolol (LTFC) versus dorzolamide/ Measurements included full ophthalmic examination, visual
timolol (DTFC) fixed combinations and to investigate acuity, Goldmann IOP, central corneal thickness (CCT) (OcuS-
their effects on ocular hemodynamics and structural can PXP, Alcon Labs. Inc.), Humphrey visual field examina-
and functional changes in patients with glaucoma after tion (central 30-2), and scanning laser polarimetry (GDx VCC
1 year of follow-up. Laser Diagnostic Technologies Inc., San Diego, CA). Ocular

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