Author: Oleg Kolenko (Russian Federation)
Co-authors: Oleg Kolenko
Purpose
To study the postoperative dynamics of visual acuity in relation to changes in the morphological structure and chorioretinal microcirculation in the macula at the stage of completion of silicone tamponade after endovitreal surgery in case of rhematogenous retinal detachment (RRD).
Setting/Venue
The work was performed in the S.N. Fyodorov NMRC «MNTK «Eye Microsurgery», Khabarovsk, Russia
Methods
The retrospective study included 21 patients (21 eyes) with anatomical retinal fit after endovitreal surgery, aged 25 to 56 years (mean age 46.5±15 years). Mild myopia (15 people) prevailed in the structure of refraction, emmetropia (3 people) and hyperopia (3 people) were less common. The duration of RRD varied from 8 days to 3 weeks; the period of macular detachment was calculated from the moment of decrease in central vision and ranged from 4 to 10 days. Preoperative visual acuity (VA) varied from light perception with correct light projection to 0.15 rel. The exclusion criteria from the study were patients with diabetes mellitus, glaucoma, and myopia over 3 diopters. All patients underwent a standard three-port vitrectomy with tamponade of the vitreous cavity with silicone oil. 3 months after the operation, by the time of the formation of strong chorioretinal adhesions in the area of retinal ruptures, the silicone oil was removed from the vitreous cavity. Standard ophthalmological examination included: visometry, computerized perimetry, tonometry, biomicroscopy, ultrasound A- and B-scanning. The analysis of changes in the macular region was performed by OCT: the central foveal thickness (CFT, μm), the thickness of the photoreceptor outer segments (POS, μm), the state of the layer of outer and inner segments of photoreceptors (IS / OS, abs.), defects of the outer boundary membrane (OBM, abs.) and internal boundary membrane (IBM, abs.). In order to reliably analyze intraocular blood flow, using angio-OCT, the choroidal thickness (CT, μm), the area of the foveal avascular zone (FAZ, mm2) and the density of the superficial capillary network (DSCN, %) of the retina in the macular zone were assessed in the manual mode. A variant of the norm were indicators of the morphological status of the macula and chorioretinal blood flow in 10 apparently healthy people of the same age. The studies were carried out in dynamics for 3 months after the completion of the silicone tamponade. The patients were divided into 2 groups: 1st group - 12 people (12 eyes) with a final VA equal to 0.72±0.05 (0.4-0.9); 2nd group - 9 people, whose VA by the final stage of the examination corresponded to the degree of low vision and averaged 0.24±0.04 (0.15-0.3). Statistical data processing was carried out using the IBM SPSS Statistics 20 software.
Results
Before the completion of the silicone tamponade, VA on average was similar to 0.28±0.05 in the 1st group of patients and 0.27±0.03 in the 2nd group (p<0.05). In the 1st group after removal of the silicone there was a rapid recovery of VA. During the first 7-10 days after surgery, VA averaged 0.69±0.04, and reached its maximum by the final follow-up period (3 months after surgery) and was 0.72 ± 0.05. Analysis of tomograms in postoperative dynamics revealed minimal changes in morphological structure of retina in macula in the first 1-3 days after surgery, which were limited to an increase in CFT to 361.2±9.0 μm at 250.0±5.7 μm in the control and in 2 cases (8.3±0.7%) with minimal signs of disorganization of the IS / OS and OBM lines. Restoration of the normal structure of the retina in the macula in patients of the 1st group was observed 7-10 days after removal of the silicone. According to OCT-angiography 3 months after surgery, patients in this group showed a tendency towards normalization of chorioretinal blood flow in the macula. So, by the final follow-up period, the area of nFAZ was 0.41±0.02 at 0.39±0.05 in the control group, DSCN was 53.9±3.0% at 54.4±4.5% in the control group and CT 285.0±8.1 at 290.5±7.0 in the control group (p>0.05). In patients of the 2nd group, there was no significant improvement in VA after surgery. During the first 7-10 days after the surgical intervention, VA averaged 0.23±0.01, and by the final follow-up period (3 months after the operation) it improved insignificantly, to 0.24±0.04. At the same time, in patients of this group, with low visual results of the operation, the direction of the revealed structural changes in the morphological structure and chorioretinal microcirculation in the macula have a character approximately similar to the 1st group, however, the degree of their severity and the proportion of disorders significantly prevail (p>0.05). Among the most common changes in the outer parts of the retina after the completion of silicone tamponade in patients of the 2nd group, IS / OS line defects and OBM injuries prevailed in frequency, which occurred in 10 patients. Defects of the IBM and epiretinal membranes in the analysis of tomograms by the end of the observation period were diagnosed, respectively, in every 3rd and 2nd patient in the absence of such in the 1st group. The duration of the transient increase in CFT in patients of the 2nd group averaged from 7 to 10 days versus 1-3 days in the 1st group of patients (p<0.05). According to OCT angiography, chorioretinal blood flow in the macula in the dynamics of the postoperative period in patients of the 2nd group, in contrast to the 1st, did not have a clear tendency to normalization and stabilization. By the final follow-up, these patients had an increase in the FAZ area up to 1.551±0.005 mm at 0.39±0.05, a decrease in DSCN to 41.4±3.0% at 54.4±4.5% and a decrease in CT to 242.0±7.9 at 290.5±7.0 in the control group (p<0.05).
Conlusions
1. As a result of a retrospective analysis of the postoperative dynamics of VA in operated patients with RRD at the stage of completion of silicone tamponade, according to tomograms, it was found that the main cause of low VA is structural changes in the neuroepithelium in the macula, disorganization of the IS / OS line, defects in the OBM and IBM, and the presence in the macula signs of the epiretinal membrane. 2. During OCT-angiography, a relationship was revealed between the degree of decrease in VA, morphological changes in the macula and the severity of disturbance of chorioretinal blood flow in the macula. Operated patients with low visual acuity are characterized by: prolonged and pronounced capillary hyperperfusion, which ends 3-10 days after removal of the silicone with a persistent deficit of chorioretinal microcirculation in the macula.
Financial Disclosure
No
Comments
-
