Purpose To evaluate factors associated with visual field (VF) progression, using all available follow-up through nine years after treatment initiation, in the Collaborative Initial Glaucoma Treatment Study (CIGTS). Design Longitudinal follow-up of participants enrolled in a randomized clinical trial. Participants 607 newly diagnosed glaucoma patients. Methods In a randomized clinical trial, 607 subjects with newly diagnosed open-angle glaucoma were initially treated with either medication or trabeculectomy. After treatment initiation and early follow-up, subjects were evaluated clinically at 6-month intervals. Study participants in both arms of the CIGTS were treated aggressively in an effort to reduce intraocular pressure (IOP) to a level at or below a predetermined, eye-specific target pressure. VF progression was analyzed using repeated measures models. Main outcome measures VF progression, measured by Humphrey 24-2 full threshold testing and assessed by the change in the mean deviation (MD), and an indicator of substantial worsening of the VF (MD decrease of ≥3 dB from baseline), assessed at each follow-up visit. Results Follow-up indicates minimal change from baseline in each initial treatment group’s average MD. However, at the eight year follow-up examination, substantial worsening (≥3 dB) of MD from baseline was found in 21.3% and 25.5% of the initial surgery and initial medicine groups, respectively. The effect of initial treatment on subsequent VF loss was modified by time (P<0.0001), baseline MD (P=0.03), and diabetes (P=0.01). Initial surgery led to less VF progression than initial medicine in subjects with advanced VF loss at baseline, whereas subjects with diabetes had more VF loss over time if treated initially with surgery. Conclusions The CIGTS intervention protocol led to a lowering of IOP that persisted over time in both treatment groups. Progression in VF loss was seen in a subset increasing to over 20% of the subjects. Our findings regarding initial surgery being beneficial for subjects who present at diagnosis with more advanced VF loss, but detrimental for patients with diabetes, are noteworthy and warrant independent confirmation.

Objective To evaluate the impact of measures of intraocular pressure (IOP) control on progression of visual field (VF) loss during long-term treatment for open-angle glaucoma (OAG). Design Longitudinal, randomized clinical trial. Participants 607 participants with newly-diagnosed OAG. Methods Study participants were randomly assigned to initial treatment with medications or trabeculectomy, and underwent examination at six-month intervals. Standardized testing included Goldmann applanation tonometry and Humphrey 24-2 full threshold VFs. Summary measures of IOP control during follow-up included the maximum, mean, standard deviation (SD), range, proportion less than 16, 18, 20, or 22 mmHg, and whether all IOP values were less than each of these four cut-points. Predictive models for VF outcomes were based on the mean deviation (MD) from VF testing, and were adjusted for age, sex, race, baseline VF loss, treatment, and time. Each summary IOP measure was included as a cumulative, time-dependent variable, and its association with subsequent VF loss was assessed from 3 to 9 years post-randomization. Both linear mixed models, to detect shifts in MD levels, and logistic models, to detect elevated odds of substantial worsening (3 dB or more), were used. Main Outcome Measure MD from Humphrey 24-2 full threshold VF tests. Results The effect of the summary IOP measures differed between the medicine and surgery groups in models that addressed the continuous MD outcome. After adjustment for baseline risk factors, in the medicine group larger values of three IOP control measures – maximum IOP (p=0.0003), standard deviation of IOP (p=0.0056), and range of IOP (p<0.0001) – were significantly associated with lower (worse) MD in the 3 to 9 year period. No IOP summary measure was significantly associated with MD over time in the surgery group. The same three IOP summary measures were also significantly associated with substantial worsening of MD; however, the effects were similar in both treatment groups. In models predicting inadequate IOP control, consistently significant predictors of higher maximum, SD, and range of IOP included black race, higher baseline IOP, and clinical center. Conclusions These results support considering more aggressive treatment when undue elevation or variation in IOP measures is observed.

Purpose: To evaluate the relationship between medication adherence and visual field progression in participants randomized to the medication arm of the Collaborative Initial Glaucoma Treatment Study (CIGTS).Design: The CIGTS was a randomized, multicenter clinical trial comparing initial treatment with topical medications to trabeculectomy for 607 participants with newly diagnosed glaucoma.Participants: Three hundred seven participants randomized to the medication arm of the CIGTS. Methods: Participants were followed up at 6-month intervals for up to 10 years. Self-reported medication adherence and visual fields were measured. Medication adherence was assessed by telephone from responses to the question, "Did you happen to miss any dose of your medication yesterday?" The impact of medication adherence on mean deviation (MD) over time was assessed with a linear mixed regression model adjusting for the effects of baseline MD and age, cataract extraction, interactions, and time (through year 8, excluding time after crossover to surgery). Medication adherence was modeled as a cumulative sum of the number of prior visits where a missed dose of medication was reported.Main Outcome Measure: Mean deviation over time.Results: Three hundred seven subjects (306 with adherence data) were randomized to treatment with topical medications and followed up for an average of 7.3 years (standard deviation, 2.3 years). One hundred forty-two subjects (46%) reported never missing a dose of medication over all available follow-up, 112 patients (37%) reported missing medication at up to one third of visits, 31 patients (10%) reported missing medication at one third to two thirds of visits, and 21 patients (7%) reported missing medication at more than two thirds of visits. Worse medication adherence was associated with loss of MD over time (P ¼ 0.005). For subjects who reported never missing a dose of medication, the average predicted MD loss over 8 years was 0.62 dB, consistent with age-related loss (95% confidence interval [CI], 0.17e1.06; P ¼ 0.007); subjects who reported missing medication doses at one third of visits had a loss of 1.42 dB (95% CI, 0.86e1.98; P < 0.0001); and subjects who reported missing medication doses at two thirds of visits showed a loss of 2.23 dB (95% CI, 1.19e3.26; P < 0.0001).Conclusions: This longitudinal assessment demonstrated a statistically and clinically significant association between medication nonadherence and glaucomatous vision loss.