Clinical and Experimental Ophthalmology 2004; 32: 368–372 Original Article _____________________________________
Five-year follow up of selective laser trabeculoplasty in Chinese eyes
Jimmy SM Lai FRCOphth,1 John KH Chua FRCS,2 Clement CY Tham FRCS2 and Dennis SC Lam FRCOphth2 1Department of Ophthalmology, United Christian Hospital, and 2Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China ABSTRACT Purpose:
Selective laser trabeculoplasty in Chinese eyes
This randomized, prospective study evaluated the effec-
throughout 360° of the TM. Immediately following laser
tiveness and safety of SLT compared with medical treatment
treatment, one drop of 1% apraclonidine and 1% pred-
in patients with POAG or OHT in Chinese eyes.
nisolone acetate were administered to the laser-treated eye. The prednisolone acetate eye drop was continued at afrequency of 4 times per day for 7 days.
Intraocular pressures of the laser-treated and the fellow
The study was approved by the Ethics Committee of the
eyes were measured with Goldmann applanation tonometer
Chinese University of Hong Kong. Patients newly diag-
hourly for 2 h following SLT and continued to be monitored
nosed with POAG or OHT were included in the study. All
hourly if the rise was more than 5 mmHg. Anterior chamber
patients had IOP >21 mmHg in both eyes without anti-
reaction was assessed by slit-lamp biomicroscopy. For the
glaucomatous medications and those with POAG demon-
fellow eyes, topical antiglaucoma medications including -
strated optic disc changes and/or visual field changes typical
blocker, pilocarpine, dorzolamide and latanoprost were started
of glaucomatous damage. Exclusion criteria included previ-
either as monotherapy or in combination 2 h after SLT.
ous laser trabeculoplasty, previous intraocular surgery dis-
Patients were followed up after 1 day, 1 week, 2 weeks,
turbing the aqueous outflow, active ocular inflammation,
1 month, 3 months and 6 months and then yearly after
poor visualization of the trabecular meshwork, single eye
the laser treatment. During these visits, the following
and pregnancy. Written informed consent was obtained
parameters were assessed: IOP measured with Goldmann
from every patient prior to the study.
applanation tonometer, best-corrected visual acuity by the
Patients included in this study were screened twice with
standard Snellen chart, slit-lamp biomicroscopy of the
an interval of 2 weeks before receiving the laser treatment.
anterior segment, gonioscopy, fundal examination including
During the first screening examination, the following were
assessment of the cup/disc ratio. The degree of TM pigmen-
recorded: IOP measured with Goldmann applanation
tation and the presence of peripheral anterior synechiae
tonometer, best-corrected visual acuity by the standard
Snellen chart, slit-lamp biomicroscopy of the anterior
The primary aim of this study was to evaluate the IOP
segment, gonioscopy, fundal examination including the
lowering effect and safety of SLT. The outcome was ana-
assessment of cup/disc ratio and visual field assessment by
lysed based on the magnitude of the IOP reduction and the
static automated perimetry (Humphrey full-threshold central
mean number of medications at yearly follow-up intervals.
Failure was defined as IOP > 21 mmHg on maximal toler-
Intraocular pressure measurement with Goldmann appla-
nation tonometry was performed at the second screeningexamination. Patients were excluded if the baseline IOP of
one eye differed from the fellow eye by more than 15% ateither of the two screening visits. For recruited subjects, IOP
A total of 64 eyes of 32 patients were included in the study
was measured in two separate visits. The average of the two
from March to June 1998 at the Prince of Wales Hospital,
measurements was taken as the baseline IOP. One eye of
the Chinese University of Hong Kong. Three patients
each patient was randomized by computer-generated alloca-
defaulted follow up within 6 months of commencement
tion schedule to receive SLT (Group 1) and the fellow eyes
of treatment and were excluded. Data from the remaining
received medical treatment (Group 2). To minimize the
29 patients (58 eyes) were analysed. Twenty-four patients
extent of cross-over effect with medical treatment, patients
(82.8%) were successfully followed up yearly for a period
were instructed to apply digital lacrimal punctual pressure
of 5 years. All patients were Chinese with dark brown iris.
for 5 min after instilling the eye drops.
The mean age was 51.9 ± 14.7 years with 13 men and 16
The laser procedure was performed by one surgeon
women. Seventeen patients were diagnosed to have POAG
(JSML) under topical anaesthesia with proparacaine. One
and 12 had OHT. The best-corrected visual acuity ranged
drop of 1% apraclonidine was instilled into the eye to receive
from 0.1 to 1.0 in group 1 and from 0.2 to 1.0 in group 2.
SLT 1 h prior to treatment. The Selecta 7000 frequency-
The mean cup/disc ratio was 0.4 ± 0.2 in group 1 and
doubled Q-switched Nd:YAG laser (Coherent, Palo Alto,
0.5 ± 0.2 in group 2 (P = 0.95, Student’s t-test). The mean
CA, USA) was used. A 3-mirror Goldmann goniolens was
placed on the cornea and the trabecular meshwork was
26.2 ± 4.2 mmHg in Group 2 (P = 0.62, Student’s t-test).
brought into focus using the modified Coherent LDS-10 slit
The mean IOP reduction was 8.6 ± 6.7 mmHg (32.1%)
lamp with LAS-10 spot mirror illumination.
in group 1 and 8.7 ± 6.6 mmHg (33.2%) in group 2 at the
The initial laser energy was set at 0.8 mJ. A single laser
5-year follow-up visit (P = 0.95, Student’s t-test). Figure 1
pulse was delivered starting at the 12 o’clock position. The
shows the short and long-term mean IOP reductions after
energy was then increased or decreased by 0.1 mJ until
treatment in both groups. There was no significant differ-
bubble formation became just invisible. Treatment was
ence in the mean IOP reductions between the two groups
then continued in single-burst mode at this energy level
from day 1 to the last follow up at 5 years. In the SLT group,
until about 100 non-overlapping laser spots were placed
eight eyes (27.6%) required additional medical therapy to
Mean number of medications in (᭜) the selective laser
trabeculectomy group and () the medical treatment group. P < 0.001 at all time intervals (Student’s t-test). Figure 1.
(a) Short-term and (b) long-term intraocular pressure
(IOP) reductions in (᭜) the selective laser trabeculectomy groupand () the medical treatment group. P > 0.05 at all time intervals(Student’s t-test). Figure 3.
Kaplan–Meier curve showing survival probability of
control the IOP to below 21 mmHg. One of these eight
(᭜) the selective laser trabeculectomy group and () the medical
eyes required supplementary medication as early as 4 weeks
after the SLT and the remaining seven eyes only requiredsupplementary medications 1 year after SLT. The meannumber of medications required for IOP control remained
carpine, dorzolamide, latanoprost or various combinations
significantly lower in the SLT than the medical treatment
of them. In the SLT group, the eight patients who required
group up to the last follow up at 5 years (P < 0.001, Student’s
supplementary medications during 5-year follow up were
t-test). Figure 2 shows the mean number of medications at
put on topical β-blocker. Two of them required dorzo-
various time points. The mean number of medications
lamide and one required latanoprost in addition to the
required to control the IOP ranged from 0.46 to 0.55 in the
SLT group and from 1.45 to 1.63 in the medical treatment
The mean laser energy per spot to achieve the endpoint
group. The number was significantly lower in the SLT group
was 1.0 ± 0.1 mJ. The mean total laser energy used was
during the 5-year follow up (P < 0.001).
73.6 ± 16.4 mJ. Transient postlaser IOP spike of greater
Five eyes (17.2%) in the SLT group and eight eyes
than 5 mmHg was observed in three eyes (10.3%). No
(27.6%) in the medical treatment group had IOP >21 mmHg
persistent anterior chamber reaction beyond 1 week post-
despite maximal medications and required filtration surgery.
laser was recorded. No patients in group 1 had increase in
However, the difference in the failure rates defined as IOP
TM pigmentation or formation of peripheral anterior syn-
>21 mmHg on maximal medications was not statistically
echiae as a result of the laser treatment. The mean cup/disc
significant (P = 0.53, χ2 test). The Kaplan-Meier curve in
ratio at 5 years was 0.5 ± 0.2 in group 1 and 0.5 ± 0.2 in
Fig. 3 shows the survival probability of both treatment
group 2. There was no statistically significant change com-
groups. In the remaining patients, those in the medical
pared to the pretreatment ratio. (P = 0.80 group 1, P = 0.78
treatment group were put on either topical β-blocker, pilo-
Selective laser trabeculoplasty in Chinese eyes
Treatment Study.19 We tried to minimize this cross-overeffect by applying lacrimal punctual pressure for 5 min
Argon laser trabeculoplasty, introduced by Wise and
after administration of eye drops. Ariturk et al. have shown
Witter, effectively decreases IOP in patients with POAG1
that occlusion of the nasolacrimal canal by plugging the
but the laser energy induces thermal injury in the pigmented
punctum significantly increased the IOP reduction effect of
TM cells with concurrent damage to the adjacent non-
antiglaucoma eye drops but there was no significant change
pigmented cells and collagen trabecular beams.4,5 SLT is a
in the IOP in the unplugged eyes.20 Nevertheless our results
frequency-doubled Q-switched Nd:YAG (wavelength 532 nm)
should be interpreted with the potential overestimation of
laser system that delivers energy with short pulse duration
and low fluence to the target tissues. It selectively targets
In conclusion, the IOP lowering effect of SLT in this
pigmented TM cells without coagulative damage to the
group of Chinese patients with POAG or OHT is effective.
adjacent tissues, and histological studies showed minimal
SLT significantly reduces the number of antiglaucoma
damage in the trabecular beams and endothelial cells in eyes
medications required for IOP control. Its IOP lowering
effect is fast in onset and is maintained in the majority of
We adopted the regimen of using 1% apraclonidine 1 h
cases up to 5 years. Immediate postlaser IOP spike and
before and immediately after SLT. Only three eyes (10.3%)
persistent anterior chamber reaction were minimized by the
had increased IOP >5 mmHg within 2 h after laser treat-
use of apraclonidine and short-term topical steroid, respec-
ment. These three patients were monitored hourly and the
tively. Long-term excessive angle scarring in the form of
IOP came down to <5 mmHg of baseline within 4 h after
peripheral anterior synechiae was not noted. The overall
laser treatment. The incidence is lower than the ALT series
clinical response was similar to reported series in non-
reported in the Glaucoma Laser Trial Research Group
(34%)16 and the SLT series reported by Latina et al. (24%).12The mean laser energy per spot required to reach the end-point in our pigmented eyes was similar to that required in
non-Asian eyes. No persistent anterior chamber reaction
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From our study, the mean IOP in Group 1 of the SLT-
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Randomized clinical trial Randomized clinical trial of trigger point infiltration with lidocaine to diagnose anterior cutaneous nerve entrapment syndrome O. B. A. Boelens1, M. R. Scheltinga1, S. Houterman2 and R. M. Roumen1 1 Department of Surgery and 2M´axima Medical Centre Academy, M´axima Medical Centre, Veldhoven, The Netherlands Correspondence to: Mr O. B. A. Boelens, Department o
ŁUKASZ NOWAK1, DANIEL ŻUROWSKI1, JAN DOBROGOWSKI3, JERZY WORDLICZEK2,PENTOXIFYLLINE MODIFIES CENTRAL AND PERIPHERALVAGAL MECHANISM IN ACUTE AND CHRONIC PAIN MODELS Abstract: Pentoxifylline modifi es central and peripheral vagal mechanism in acute and chronic pain models. The infl ammatory process gives the way to hyperalgesia that is documented by the animal experimental studies. Pentoxi