B. Blackwell et al., The Advanced Glaucoma Intervention Study, 8: Risk of cataract formation after trabeculectomy, ARCH OPHTH, 119(12), 2001, pp. 1771-1780
Objectives: To compare the risk of cataract formation in eyes with and with
out prior trabeculectomy and to assess other risk factors for cataract.
Methods: The Advanced Glaucoma Intervention Study (AGIS) has been following
789 eyes in 591 patients with medically uncontrolled open-angle glaucoma.
From 1988 to 1992, these eyes were randomly assigned to either an argon las
er trabeculoplasty (ALT)-trabeculectomy-trabeculectomy treatment sequence o
r a trabeculectomy-ALT-trabeculectomy sequence. Cox regression analyses wer
e used to assess risk factors for cataract formation during 7 to 11 years o
f follow-up.
Main Outcome Measures: Cataract, defined as either having had cataract surg
ery or confirmed severe lens opacity with a best-corrected Early Treatment
Diabetic Retinopathy Study visual acuity score less than 65 letters (worse
than 20/50).
Results: Data are presented on the expected 5-year cumulative probability o
f cataract formation in each randomized sequence by age and presence of dia
betes at study entry. Overall, approximately half of the eyes studied devel
oped cataract. A first trabeculectomy, whether as the first or second AGIS
intervention, increased the overall risk of cataract by 78% (risk ratio [RR
]=1.78; P < .001). Diabetes (RR=1.47; P=.004) and age at study entry (RR=1.
07 per year of age; P < .001) were also risk factors for cataract. When pos
toperative complications of trabeculectomy were included in the analysis, t
he increased risk of cataract for eyes with a first trabeculectomy reduced
to 47% when complications did not occur (RR=1.47; P=.003) and increased to
104% when complications did occur (RR=2.04; P < .001). Several specific pos
toperative complications of trabeculectomy were associated with increased r
isk of cataract, particularly marked inflammation (RR=3.29; P < .001) and f
lat anterior chamber (RR=1.80; P=.004). Trabeculectomy with complications w
as also significantly associated with an increased risk of cataract in each
of 3 lens regions: nuclear, cortical, and posterior subcapsular.
Conclusions: In eyes of AGIS patients, after adjustment for age and diabete
s, trabeculectomy increased the risk of cataract formation by 78%.