Consistent Injections Better Maintain Visual Acuity, Study Says

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Research shows how patients with AMD who are lost to follow-up face worse vision in time.

Patients with exudative age-related macular degeneration (AMD) who maintained 20/40, or better, vision at the conclusion of a 7-year study received more intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections per year than eyes with worse than 20/40 vision, according to researchers at the Mayo Clinic in Rochester, Minnesota. 

A publication in Ophthalmology Retina suggests that acuity can be best maintained for longer periods when patients undergo consistent treatment. 

“It is difficult to ascertain whether a fixed continuous approach vs a treat-and-extend regimen leads to superior long-term outcomes over each other, but it does seem that eyes with more injections over time achieve better long-term VA results,” the researchers explain. 

The investigators conducted a 7-year retrospective study of all patients — 391 eyes in total — diagnosed with exudative AMD who received anti-VEGF injections at the clinic between January 1, 2005 and December 31, 2009. Any patients who received intravitreal anti-VEGF injections for diseases other than AMD. Researchers also only included patients who had been treated with at least 2 injections and had received follow-up care every year for 7 years. Patients who didn’t receive consistent follow-up care were placed in a comparison cohort.

Patients were treated with ranibizumab 0.5 mg/0.05 ml, bevacizumab 1.25 mg/0.05 ml, or aflibercept 2 mg/0.05 ml. Researchers measured their visual acuities using Snellen acuity and converted them tologMAR. Visual acuity was noted at the time anti-VEGF therapy began and then annually thereafter for the next 7 years. Most patients were managed initially with monthly anti-VEGF injections and then moved to a modified treat-and-extend treatment plan.

Investigators found that a significant decline in visual acuity occurred from baseline to the year 7 visit, beginning at year 5. Patients initially received injections more frequently only to decline during years 2 through 4, the research shows. Frequency then slowly increased over time, according to the findings. Despite a drop in the total number of injections from years 2 through 4 in both groups, the eyes that maintained vision better than 20/40 received more injections per year than those eyes with worse vision.

Specifically, at the start of the study, the baseline mean visual acuity was approximately 0.6logMAR and the 7-year visual acuity was approximately 0.8 logMAR. 

Compared with the 142 eyes that were not seen during an office visit for a continuous 12-month period, eyes seen during annual office visits showed similar baseline mean visual acuity (0.7 logMAR vs. 0.6 logMAR; P =.2102), but more injections per year (P <.0001). Of the 533 total eyes, 124 eyes (23%) maintained better than 20/40 visual acuity at 7 years. These eyes received more injections overall per year (6.5 vs 5.5 injections per year; P =.0007).

The research points to previous trials of anti-VEGF treatment that found improvements in visual acuity 1 and 2 years after starting continuous treatment. However, later studies that followed up on these patients after trials ended found that the initial improvement in visual acuity wasn’t maintained. Subsequent long-term studies found that patients who received continuous injections in either a fixed or treat-and-extend protocol showed improved visual acuity compared with baseline and those improvements were maintained for several years.

“It is imperative that these patients not be lost to follow-up for extended periods because of the detrimental effect it may have on their vision and

potential ability to maintain visual acuity,” the researchers advise.

Limitations of the study include its retrospective cohort design. Secondly, investigators didn’t differentiate patients by the type of anti-VEGF agent used or note if patients switched agents during treatment. Third, while investigators didn’t find any differences in baseline characteristics between the “consistent” and “inconsistent” follow-up cohorts, other characteristics, such as socioeconomic status or distance to a clinic, might have impacted follow-up and, in turn, visual acuity outcomes.

None of the authors reported any conflicting interests.


Kung FF, Starr MR, Bui YT, et al. Long-Term Follow-up of Patients with Exudative Age-Related Macular Degeneration Treated with Intravitreal Anti–Vascular Endothelial Growth Factor Injections. Ophthalmol Retina. 2020;4(11):1047-1053. doi: 10.1016/j.oret.2020.05.005.