We wish to thank Dr Uzun for his letter and his valuable remarks regarding our recently published article.
Dr Uzun writes, summarizing our article, that we did not determine any significant difference between pre- and postoperative central retinal thickness, which is incorrect. Changes in pre- and postoperative retinal thickness are listed in Table 1 of our paper. Postoperative central retinal thickness was significantly lower when compared with preoperative central retinal thickness ( P < .05). Most earlier authors confirm these data. We wrote that retinal thickness did not change during the preoperative period (between 12 months and 1 week preoperatively). Decrease of visual acuity in the preoperative period was suggested to be associated with increasing deformation of the inner retinal layers.
Dr Uzun additionally comments that the choroid shows significant diurnal variations. We completely agree that measurements of choroidal thickness depend on many factors, such as age, axial length, refractive error, caffeine uptake, nicotine abuse, or even time of the day. Because of this, we examined all of our patients at the same time of the day, between 3 PM and 6 PM. Choroidal thickness was reported to be least susceptible to diurnal variations and, thus, to change the least during this timeframe. Additionally, we excluded patients with refractive errors greater than −2 and +2 diopters to reduce the role of axial length and refractive error in determining choroidal thickness. As Dr Uzun noted, the average age of patients in our group was 68. We reviewed their medical histories and found that many of them were in fact treated for arterial hypertension (14 of 29 patients), 3 had suffered earlier heart infarct, 1 patient was diabetic (without diabetic retinopathy), and 4 patients had concomitant glaucoma (well controlled with eye drops). No significant changes of the health status of the patients were noted during the follow-up. Thus, even if any of those factors might have influenced the initial measurement of choroidal thickness, it is less probable that it influenced changes in choroidal thickness after vitrectomy. Owing to the limited number of patients, great variability in systemic diseases, and differences in drug uptake, it was impossible to gather adequate statistics. We agree with Dr Uzun that a larger study focusing on choroidal thickness after vitrectomy in patients with and without heart disease and arterial hypertension or any other systemic factors would be required to adequately address all concerns.
In our opinion, the main points of our study were as follows: Firstly, we concluded that patients with more irregularities at the outer choroidoscleral boundary recovered visual acuity more rapidly after surgery. Secondly, we confirmed with multivariate analysis that 3 factors are associated with more frequent visibility of the suprachoroidal layer: multiple adhesion points between the retina and epiretinal membrane, increased central retinal thickness, and a wavy (more irregular) outer border of the plexiform layers. Finally, during the preoperative period, the main factor associated with the worsening of visual acuity was not photoreceptor defects but progression of the deformation of the inner retinal layers.