F. Ederer et al., The advanced glaucoma intervention study, 6: Effect of cataract on visual field and visual acuity, ARCH OPHTH, 118(12), 2000, pp. 1639-1652
Objective: To investigate the effect of cataract on visual function and the
role of cataract in explaining a race-treatment interaction in outcomes of
glaucoma surgery.
Methods; The Advanced Glaucoma Intervention Study (AGIS) enrolled 332 black
patients (451 eyes) and 249 white patients (325 eyes) with advanced glauco
ma. Eyes were randomly assigned to an argon laser trabeculoplasty (ALT)-tra
beculectomy-trabeculectomy sequence or a trabeculectomy-ALT-trabeculectomy
sequence. From the AGIS experience with cataract surgery during followup, w
e estimated the expected change in visual function scores from before catar
act surgery to after. cataract surgery. Then, for eyes with cataract not re
moved, we used these estimates of expected change to adjust visual function
scores for the presumed effects of cataract. in turn, we used the adjusted
scores to obtain cataract-adjusted main outcome measures.
Main Outcome Measures: Average percent of eyes with decrease of visual fiel
d (APDVF) and average percent of eyes with decrease of visual acuity (APDVA
).
Results: Within the 2 months before cataract surgery, visual acuity was bet
ter ill eyes of white patients than of black patients by an average of appr
oximately 2 lines on the visual acuity test chart. Cataract surgery improve
d visual acuity and visual field defect scores, with the amounts of improve
ment greater when preoperative visual acuity was lower. Adjustments for cat
aract brought about the following relative reductions: for APDVF, a relativ
e reduction of 5% to 11% in black patients and 9% to 11% in white patients;
for APDVA, a relative reduction of 45% to 49% in black patients and 31% to
38%, in white patients; and for the APDVF and APDVA race-treatment interac
tions, relative reductions of 25% and 45%, respectively.
Conclusions: On average, visual function scores improved after cataract sur
gery. The findings of reduced race treatment interactions after adjustment
for cataract do not alter our earlier conclusion that the AGIS 7-year resul
ts support use of the ALT-trabeculectomy trabeculectomy sequence for black
patients and of the trabeculectomy-ALT-trabeculectomy sequence for white pa
tients without life-threatening health problems. The choice of treatment sh
ould take into account individual patient characteristics and needs.