The Laser in Glaucoma and Ocular Hypertension (LiGHT) Trial is a
multicenter randomized controlled trial comparing initial treatment using
selective laser trabeculoplasty (SLT) with initial treatment with IOP-lowering
eye drops.
The study was performed on treatment-naïve patients with open-angle
glaucoma (OAG) or ocular hypertension (OHT), assessing health-related quality
of life (HRQoL), cost-effectiveness, and clinical efficacy after 3 years.
The initial results of the LiGHT Trial were reported in 2019. The
study found that initial treatment of OHT or OAG with SLT is more
cost-effective than initial treatment with contemporary IOP-lowering eye drops
after 3 years,
It also reported freedom from drops to 74.2% of patients, a reduced
number of glaucoma surgeries, and very low rates of adverse events.
SLT was performed according to a predefined protocol at 360-degrees
of the trabecular meshwork with 100 nonoverlapping shots (25 per quadrant;
energy, 0.3-1.4 mJ).
For the first 36 months (3 years) of the trial, 1 additional SLT
retreatment was allowed (total of 2 SLT treatments), and thereafter, the next
escalation was medical treatment.
Single-drug eye drops were prescribed initially after randomization
for patients in the drops arm and for patients whose IOP remained uncontrolled
after SLT.
Different or additional eye drops were prescribed in the event of a
treatment switch (e.g., adverse reaction) or treatment escalation (e.g., IOP
above target).
Drug classes for first-line, second-line, or third-line treatment
were defined according to NICE and the European Glaucoma Society guidance:
first line, prostaglandin analogs; second line, bblockers; and third or fourth
line, topical carbonic anhydrase inhibitors or a-agonists.
Fixed combination drops were allowed; systemic carbonic anhydrase
inhibitors were permitted only as a temporary measure while awaiting surgery
and were not considered a treatment escalation for the purposes of the
analysis.
For the first 36 months (3 years) of the trial, patients initially
randomized to receive IOP-lowering eye drops were not permitted SLT; failure to
control IOP or OAG with eye drops resulted in surgical treatment
(trabeculectomy).
After the first 3 years, patients were allowed a crossover, whereby
they could opt to undergo SLT as a treatment switch, that is, to reduce
medication load, or as a treatment escalation, that is, to avoid increasing
medication load or to delay surgery.
Of the 692 patients who completed 3 years of the LiGHT Trial, 633
patients (91.5%) entered the 3-year extension (from 36 to 72 months); 313
patients (547 treated eyes) initially received SLT, and 320 patients (549 eyes)
initially commenced treatment with IOP-lowering eye drops.
Of the 320 patients allocated to medication, 112 patients (176
eyes; 35% of patients) decided to undergo SLT immediately or shortly after the
end of the 3-year monitoring period.
Drop-free IOP control at 72 months, was achieved in 69.8% of eyes
initially treated with SLT compared with 18.0% of eyes initially treated with
IOP-lowering eye drops.
At 72 months, 61.2% of eyes initially treated with eye drops were
using 1 or 2 medications compared with 18.5% of eyes initially treated with
SLT.
Data published previously have indicated that initial treatment
with SLT may delay progression of OHT and OAG. VF analysis suggests more eyes
initially treated with IOP-lowering eye drops undergo rapid VF progression
compared with eyes first treated with SLT.
After 6 years of treatment, eyes initially treated with SLT
demonstrated reduced objectively defined progression compared with IOP-lowering
eye drops; this was achieved despite eyes initially treated with IOP-lowering
eye drops achieving lower IOP at 6 years, possibly suggesting other protective
roles of SLT.
Eyes initially treated with SLT needed fewer trabeculectomies. For
the first 3 years after initial treatment, no trabeculectomies were needed in
eyes receiving initial SLT. At 6 years, 3 times fewer eyes initially treated
with SLT required a trabeculectomy, compared with eyes initially treated with
eye drops.
Selective laser trabeculoplasty also leads to a reduced need for
cataract surgery. 50% more eyes initially treated with eye drops needed
cataract surgery during the 6- year course of the LiGHT Trial compared with
eyes initially treated with SLT.
For the first 3 years of the LiGHT Trial, patients using drops
experienced comparable HRQoL to those who received initial SLT, and these
findings are supported further by the LiGHT Trial extension to 6 years.
The safety profile of SLT remains very good, with no
sight-threatening complications. Intraocular pressure rose > 5 mmHg from IOP
before treatment in only 1% of treated eyes, and of these, only 1 eye needed
treatment.
