We have read and reviewed the article entitled “Short-Term Changes in Choroidal Thickness After Aflibercept Therapy for Neovascular Age-Related Macular Degeneration,” by Koizumi and associates, with interest. Choroidal thickness (CT) was analyzed in 102 eyes of 102 patients with treatment-naïve neovascular age-related macular degeneration (AMD) using either swept-source optical coherence tomography (OCT) or enhanced-depth imaging OCT. All 102 eyes underwent injections of 2.0 mg intravitreal aflibercept for 3 consecutive months: at baseline, month 1, and month 2.
The authors demonstrated that the mean baseline subfoveal CT decreased from 252.0 ± 99.7 μm to 217.9 ± 95.6 μm at month 3, after intravitreal aflibercept injections. In addition, the mean CT measurements done 3 mm away from the foveal center in the superior, inferior, temporal, and nasal directions showed significant reductions. We would like to ask for further details, and contribute to the paper.
We realized that the axial length (AL) and intraocular pressure (IOP) measurements of the participants were not analyzed in the study. Axial length and IOP were shown to have significant effects on CT. Sanchez-Cano and associates demonstrated a strong negative correlation between subfoveal AL and CT in healthy adults. Additionally, Saeedi and associates showed a negative correlation between IOP and mean CT. On the other hand, we have anticipated that intravitreal aflibercept injections may affect CT by increasing IOP, since it has already been demonstrated in the literature that aflibercept may significantly increase IOP. Therefore, AL and IOP measurements should be taken into consideration while analyzing CT in such studies.
Another important issue is the diurnal variation of CT. Usui and associates demonstrated that diurnal variation of CT might be up to 65 μm. Therefore it should be expected that physiologic fluctuation of CT might affect test measurement results and statistical analyses. We suggest performing OCT measurements along with preoperative and postoperative follow-up examinations at the same time, and at certain time periods of the day.
In addition, various local or systemic physiological/pathologic conditions affect CT. We wonder whether the authors evaluated the participants of this study for systemic diseases (diabetes mellitus, hypertension, hyperlipidemia, etc), medications used previously, and body mass index, as well as for sleeping and exercise status and for consuming of alcohol and beverages with or without caffeine before OCT testing. We are also curious about the systemic blood pressure measurement results.