Combined surgery safe for PEX patients
PHILADELPHIA - Simultaneous cataract and filtering surgery is safe
and effective for the challenging population of patients with pseudoexfoliation
(PEX) glaucoma, according to a study presented at the annual ASCRS
symposium on Cataract, IOL and Refractive Surgery.
Researchers at the Massachusetts Eye and Ear Infirmary, in the second
stage of a two part study evaluating the risks and outcomes of cataract
surgery in patients with PEX, compared two groups of eyes undergoing
combined surgery: 156 eyes with PEX and 99 control glaucomatous eyes
They found no significant between-group differences in efficacy of
the filtering surgery, as measured by reductions in IOP and glaucoma
medication use, refractive and visual outcomes or rates of various
postoperative complications. However, intraoperative complications
were more common in the PEX group and those events were related to
zonular weakness. Among eyes with PEX, zonular weakness was noted
in 10 and vitreous loss occurred in five of those eyes.
None of the eyes experienced capsular rupture, according to a study
conducted by James M. Heltzer MD at Harvard University, Boston, US.
He said PEX syndrome affects 10% of the Boston glaucoma clinic population.
Its role as a risk factor in both the formation of cataract and the
increased risk of complications during cataract surgery is well recognised.
While zonular weakness is cited as a primary factor for intraoperative
and postoperative complications, some reports have focused on the
contribution of capsular weakness, Dr Heltzer explained.
"Our findings from this stage of the investigation, coupled with
our data from the initial portion of the study in which there were
10 cases of zonular weakness and only one case of capsular weakness
among 297 PEX patients undergoing cataract surgery alone, suggest
that zonular weakness is the primary cataract surgery safety issue
in this population.
"It definitively addresses the question of whether zonular weakness
or capsular rupture plays the greater role in intraoperative complications,"
The eyes included in the phacotrabeculectomy study were operated on
between June 1986 and December 1999. Baseline IOP was 20.8 mm Hg in
the PEX glaucoma eyes and 21.0 mm Hg in the controls.
Achieved mean decreases in IOP postoperatively were 7.0 mm Hg in the
PEX glaucoma group and 6.5 mm Hg in the controls. The difference was
not statistically significant.
The PEX glaucoma patients decreased their glaucoma medication use
from an average of 1.8 medications per patient to 0.2. For the controls,
average medication use declined from 2.0 to 0.4 medications per patient.
Cataract surgery was performed using phacoemulsification in 93% of
PEX eyes. Only one of those cases, which developed phacodonesis intraoperatively,
was converted to extracapsular cataract extraction.
In the remaining eyes, extracapsular cataract extractions or pars
plana lensectomies were conducted because of dense nuclei or the presence
of frank preoperative phacodonesis.
Eyes with zonular weakness which underwent phacoemulsification were
implanted with large optic, polymethyl methacrylate posterior chamber
Anterior chamber IOLs were used in those eyes with vitreous loss,
and scleral-fixated lenses were placed after pars plana extractions.
Visual and refractive outcomes were similar in eyes with and without
PEX. BCVA improved from 20/80 to 20/30 in the PEX eyes and from 20/60
to 20/30 in the controls.
There was no significant difference between groups in the final spherical
The groups were also similar in incidences and types of postoperative
complications, including rates of corneal oedema, iritis and fibrinoid
The only lens dislocation occurred several weeks into the postoperative
period in a patient with PEX who suffered a fall. There were no cases
of late lens decentration or dislocation.
"Previous literature would indicate that IOL stability and risk
of late dislocation are significant concerns in eyes with PEX.
"In contrast to our expected findings, visual and refractive
outcomes were not adversely affected in our population nor did we
encounter any problems with late IOL dislocation," Dr Heltzer
As a secondary objective, the researchers characterised preoperative
features of a group of 364 PEX glaucoma patients who underwent 453
cataract procedures, either alone or in combination with trabeculectomy
and compared them with a control group of 409 patients without PEX
glaucoma who underwent 425 cataract procedures.
Those analyses found no significant differences between the groups
in age, race, IOP or number of glaucoma medications.
However, significantly more PEX patients underwent combined surgery
versus cataract extraction alone.
In addition, both diabetes and hypertension were significantly more
common in the normal population (11.5% and 49.6%, respectively) compared
with the PEX group (4.9% and 38.4%, respectively).
"Various studies have reported that PEX is associated with an
increased risk of systemic vascular diseases, including cardiac disease,
cerebrovascular accidents, aortic and abdominal aneurysms.
"Therefore, it was interesting to see in our population that
both diabetes and hypertension were less common among patients with
PEX glaucoma relative to the controls," Dr Heltzer observed.