Peripapillary changes after vitrectomy and silicone oil tamponade for rhegmatogenous retinal detachment.

PURPOSE: To evaluate the peripapillary changes after vitrectomy and silicone oil (SO) tamponade in eyes with rhegmatogenous retinal detachment (RRD). METHODS: In this study, 25-gauge vitrectomy with SO tamponade was performed in 22 eyes with RRD. The radial peripapillary capillary (RPC) vessel density (VD) and retinal nerve fiber layer thickness (RNFLT) were assessed by optical coherence tomography angiography at 2, 4, 8, and 12 weeks postoperatively. The values of healthy fellow eyes were used as controls. RESULTS: The global RPC VDs were significantly lower in the eyes with RRD than in fellow healthy eyes at 2 weeks (P < 0.001), and increased at 4 weeks, then decreased over time after surgery (F = 1.046, P = 0.377). The RPC VDs in the superior-hemifield were lower than those in the inferior-hemifield at 12 weeks postoperatively (t = -2.844, P = 0.010). The global RNFLTs decreased gradually after vitrectomy in the eyes with RRD (F = 1.312, P = 0.276). The RNFLTs in the superior-hemifield were thinner than those in the inferior-hemifield at 12 weeks postoperatively (t = -2.222, P = 0.037). The global, superior, and inferior RNFLTs were correlated with corresponding RPC VDs in the eyes with RRD at all time-points postoperatively (P < 0.05). CONCLUSION: RRD resulted in the decrease of RPC VDs. The RPC VDs recovered in the early postoperative period but were still lower than the normal level. Long-term application of SO tamponade resulted in the reduction of peripapillary VDs secondary to loss of RNFLTs.

Reduced Macular Vascular Density in Myopic Eyes.

BACKGROUND: Morphological changes of the vasculature system in patients with myopia have been observed by Doppler ultrasound and fundus fluorescein angiography (FFA); however, these studies have limitations. Doppler ultrasound provides low-resolution images which are mainly obtained from visualized large vessels, and FFA is an invasive examination. Optic coherence tomography (OCT) angiography is a noninvasive, high-resolution measurement for vascular density. The purpose of this study was to investigate the change of vascular density in myopic eyes using OCT angiography. METHODS: This cross-sectional study includes a total of 91 eyes from 47 participants including control, moderate, and high myopia that were evaluated by OCT angiography. Patients with myopia were recruited from the Refractive Department, Shenzhen Aier Eye Hospital, from August 5, 2015 to April 1, 2016. Emmetropic eyes were from healthy volunteers. The vascular density at macula and optic disc regions, ganglion cell complex (GCC) thickness, and retinal nerve fiber layer (RNFL) thickness were measured. Their relationships with axial length (AL) and refractive error were analyzed. One-way analysis of variance (ANOVA), Pearson's correlation, and generalized estimating equation were used for statistical analysis. RESULTS: Both superficial and deep macular vascular density were highest in control (25.64% ± 3.76% and 37.12% ± 3.66%, respectively), then in moderate myopia (21.15% ± 5.33% and 35.35% ± 5.50%, respectively), and lowest in high myopia group (19.64% ± 3.87% and 32.81% ± 6.29%, respectively) (F = 13.74 and 4.57, respectively; both P < 0.001). Both superficial (ß = -0.850 and 0.460, respectively) and deep (ß = -0.766 and 0.396, respectively) macular vascular density were associated with AL and spherical equivalent (all P < 0.001). Superficial macular vascular density was associated with GCC thickness (ß = 0.244, P = 0.040), independent of spherical equivalent. The vascular density in optic disc region had no difference among the three groups, and it was not associated with AL, spherical equivalent, or RNFL thickness. CONCLUSION: Our results suggested that with the increase of myopia, the vascular density decreased in macular region, but not in optic disc region.

Associated factors for visibility and width of retrobulbar subarachnoid space on swept-source optical coherence tomography in high myopia.

Subarachnoid space (SAS) around optic nerve can be visible with swept-source optical coherence tomography (SS-OCT). However, the relevant factors for its visibility and width have not been reported. In this prospective study, 193 eyes with high myopia were evaluated by SS-OCT. The relationship between age, gender, axial length, optic disc area, parapapillary atrophy (PPA) area, peripapillary choroidal thickness with the visibility and width of SAS were assessed. The results showed that SAS was observed in 125 (64.8%) and not observed in 68 (35.2%) eyes. Visibility of SAS is associated with long axial length, high myopia, thin choroid, large PPA and large optic disc areas. Among these associations, PPA area was the only independent factor (b = 0.177, p < 0.001). The width of SAS was associated with thin choroid, long axial length, large optic disc area and large PPA area. Multivariant analysis showed that optic disc area and PPA area were independent factors for the width of SAS (b = 30.8, p = 0.016 and 16.2, p < 0.001 respectively). These results suggested that SAS was extended into the peripapillary region possibly due to extension of posterior sclera in high myopia.

Topical anesthesia in transconjunctival sutureless 25-gauge vitrectomy for macular-based disorders.

PURPOSE: To evaluate the safety and feasibility of topical anesthesia in vitrectomy using the transconjunctival sutureless 25-gauge system (TSV 25G). METHODS: TSV 25G vitrectomy was performed prospectively in 46 eyes of 46 patients with macular-based disorders, including macular holes (n = 31), idiopathic epiretinal membranes (n = 11), and vitreoretinal traction syndrome (n = 4). Topical anesthesia was administered in each patient by instilling 2% Alcaine at 5 min intervals, three times before surgery. Additional Alcaine drops were given as a supplementation if needed during the operation. The levels of intraoperative analgesia were graded from 1 (adequate) to 3 (inadequate). RESULTS: Thirty-one patients (67.4%) tolerated the procedure well, with no additional anesthetic agent. Thirteen patients (28.3%) required additional topical anesthesia and 2 patients (4.3%) required a systemic sedative. Intraoperative pain occurred when the sclera was pierced by the microcannula and when sclera indentation was performed. No patient required additional retrobulbar or peribulbar anesthesia. There was no intraoperative complication which was specifically related to topical anesthesia. CONCLUSION: Topical anesthesia permits the successful management of some surgically less complex vitreoretinal disorders when the TSV 25G is used.

Experiment study of retinal ultrastructure after intravitreal FK506.

PURPOSE: To investigate the retinal toxicity of FK506 by intravitreal administration. METHODS: Twenty-two eyes of 14 New Zealand rabbits were investigated. FK506 at concentrations of 5,25 and 50 micrograms/eye was injected into the vitreous cavities respectively. The control eyes were received mixed solution of balanced salt and ethanol. All eyes were examined by tonometry, slit lamp and indirect ophthalmoscopy preoperatively and postoperatively at the 1st, 3rd, 7th, and 14th day respectively. In the final examination, all eyes were enucleated and processed for light and electron microscopy. RESULTS: No evidence of toxic reaction was seen in the eyes received 25 micrograms FK506 or less of FK506. Several eyes received 50 micrograms FK506 and control eyes developed conjunctival congestion and slightly bloody exudates in anterior chamber which may be related to irritation of ethanol. Two of five eyes received 50 micrograms developed transient vitreous opacities. Electron microscopically, the mitochondria of the photoreceptor cells were swelled in the eyes treated with 50 micrograms FK 506. CONCLUSION: It is safety with intravitreal FK506. There are no irritation and toxicity to the rabbits eyes with the intravitreal doses of 25 micrograms FK506 or less. The doses of 50 micrograms FK506 are proved to be toxic to the retina.