Scientists assessed the intraocular pressure-lowering effect of adding brimonidine as the fourth glaucoma medication to a pre-existing therapy of three topical drugs, as part of a retrospective, register-based, cohort study of medical records and computerized medical information in one county in Sweden.

The main outcome measures were short- and long-term changes in IOP after brimonidine addition.

Of 4,910 individuals on glaucoma medication, 69 (1.4 percent) initiated treatment with brimonidine as the fourth drug during 2014. Fifty-three individuals were eligible for analysis, and 46 tolerated the treatment. Among this group:
• short-term IOP decreased 17 percent (CI, 10 to 25 percent, p<0.001) after a mean of 46 days (SD 50 days); and
• 28 people (3 percent of eligible participants) remained on unchanged therapy after a mean follow-up time of 368 days (SD, 61 days).

In those who tolerated treatment, the long-term mean IOP decrease was 20 percent (CI, 11 to 29 percent, p<0.0001). A total of 28 people in short-term follow-up groups, and 14 individuals in long-term follow-up groups attained an IOP reduction of at least 20 percent.

Scientists wrote that brimonidine had the potential to reduce IOP significantly even when used as the fourth glaucoma drug. They added that roughly half of subjects reached the target IOP reduction (≥20 percent) in the short-term, and roughly a quarter of individuals sustained uneventful effects after one year. Thus, scientists suggested that using brimonidine as the fourth adjunctive drop appeared to be a valuable option for a minority of people.

Researchers looked for characteristics that distinguish individuals with diabetic macular edema with coexisting macular nonperfusion at baseline, and assessed the potential of individuals with DME to achieve favorable visual acuity, anatomic and diabetic retinopathy outcomes over 24 months, as part of a post hoc analysis of the RIDE/RISE Phase III, randomized, double-masked trials.

Participants included study eyes with best-corrected VA/fluorescein angiogram data at baseline. To measure MNP, researchers overlaid the Early Treatment for Diabetic Retinopathy Study grid on FAs of the macula. They calculated the MNP area by estimating the percentage of capillary loss in the central, inner and outer subfields, and converting the data into disc areas using a software algorithm.

Main outcome measures included:
• baseline characteristics, MNP area, BCVA and central subfield thickness at months 12 and 24; and
• incidence of study eyes with ≥2-step DR improvement at months three, six, 12, 18 and 24.

Baseline MNP was detected in 28.2 percent in the ranibizumab 0.3-mg group (n=213), 25.8 percent in the ranibizumab 0.5-mg group (n=225) and 26.3 percent in the sham arm (n=228). Findings included:
• at baseline, individuals with MNP were younger and had shorter diabetes duration, worse vision, increased CST and worse DR severity than those without MNP (p<0.01);
• in the ranibizumab 0.3-mg group, eyes with baseline MNP had lower mean baseline BCVA (53.4 ETDRS letters) than those without baseline MNP (57.2 ETDRS letters)(p=0.05), but comparable mean BCVA gain at month 24 (+15.6 ETDRS letters) than those without baseline MNP (13.4 ETDRS letters)(p=0.2);
• eyes with baseline MNP had increased CST at baseline, but a greater decrease in CST by month 24; and
• the proportion of eyes with ≥2-step DR improvements was greater for eyes with MNP than without baseline MNP in each ranibizumab arm.

Researchers found that eyes with concurrent DME and baseline MNP entering RIDE/RISE studies experienced robust VA and anatomic improvement with ranibizumab, despite having worse vision and increased CST compared with eyes without baseline MNP. As such, they recommended that these cases should not be excluded from therapy consideration.