Posterior Vitreous Detachment In Patients Research Articles

Preoperative Widefield Swept-Source Optical Coherence Tomography Versus Intraoperative Findings in Detecting Posterior Vitreous Detachment.

To assess the accuracy of swept-source optical coherence tomography (SS-OCT) in detecting complete posterior vitreous detachment (PVD) in comparison with intraoperative findings. The retrospective study included 145 eyes of 145 consecutive patients who underwent surgery for epiretinal membranes or macular holes. Within a week prior to surgery, PVD status was evaluated by SS-OCT with a depth of field of 3mm and a capture window of 16 × 8mm. Complete PVD was identified when the hyaloid condensation was visible clearly on any B-scan or when the vitreous cortex reflectivity was not visible on all 33 B-scans. Sensitivity, specificity, positive predictive value, and negative predictive value of SS-OCT for detection of complete PVD were then compared with those evaluated during a triamcinolone acetonide-assisted vitrectomy. Of the 101 eyes diagnosed as complete PVD by SS-OCT preoperatively, 97 eyes were found to have complete PVD and four eyes were found to have attached vitreous intraoperatively. Of the 44 eyes categorized as attached vitreous by SS-OCT preoperatively, 43 eyes were graded as attached vitreous and one eye was graded as complete PVD during surgery. The sensitivity of SS-OCT for detecting complete PVD was 99.0% and the specificity was 91.5%. The positive predictive value and the negative predictive value were 96.0% and 97.7%, respectively. Widefield (16 × 8mm) SS-OCT showed high accuracy for the diagnosis of complete PVD in patients with epiretinal membranes or macular holes. Widefield SS-OCT has great potential to evaluate PVD status preoperatively and explore the mechanisms of vitreoretinal diseases.

Relationship of choroidal thickness and axial length with posterior vitreous detachment in patients with high myopia

Although accumulating evidence suggests a higher prevalence of posterior vitreous detachment (PVD) in highly myopic eyes, the relation between ocular biometric features and PVD stages in such eyes remains unclear. Therefore, we enrolled 170 patients with high myopia (axial length ≥ 26.0 mm) to investigate the status of PVD regarding subfoveal choroidal thickness and axial length. Utilising swept-source optical coherence tomography, we classified the PVD status into five stages. The distribution of PVD grades increased as the choroidal thickness decreased and axial length increased (P < 0.01). On adjusting for age and sex, decreased choroidal thickness and increased axial length were associated with more advanced PVD stages: odds ratios with the highest vs. lowest groups were 0.31 (95% confidence interval [CI] 0.09–1.01; Ptrend = 0.009) for choroidal thickness and 5.16 (95% CI 1.34–19.80; Ptrend = 0.002) for axial length. The inverse association between choroidal thickness and PVD status seemed stronger in women than in men (Pinteraction = 0.05). In conclusion, we firstly observed a significant trend of decreased choroidal thickness, along with increased axial length, with increased grade of PVD, particularly among women with highly myopic eyes, suggesting that advanced morphological myopic changes contribute to PVD in middle-aged adults.

Engineering of Ocriplasmin Variants by Bioinformatics Methods for the Reduction of Proteolytic and Autolytic Activities.

Background: Ocriplasmin has been developed for the induction of posterior vitreous detachment in patients with vitreomacular adhesion. At physiological pH, ocriplasmin is susceptible to autolytic and proteolytic degradation, limiting its activity duration. These undesirable properties of ocriplasmin can be reduced by site-directed mutagenesis, so that its enzymatic activities can be augmented. This study aimed to design ocriplasmin variants with improved biological/physicochemical characteristics via bioinformatics tools.Methods: This study was performed in Tabriz University of Medical Sciences, Tabriz, Iran, 2019. Through site-directed mutagenesis, three ocriplasmin variants were designed. Structural analysis was performed on the wild-type variant and the mutant variants using the Protein Interactions Calculator (PIC) server. The interactions between the S-2403 substrate and the ocriplasmin variants were studied by molecular docking simulations, and binding capability was evaluated by the calculation of free binding energy. The conformational features of protein-substrate complex systems for all the variants were evaluated using molecular dynamic simulations at 100 nanoseconds.Results: The structural analysis of ocriplasmin revealed that the substitution of threonine for alanine 59 significantly reduced proteolytic activity, while the substitution of glutamic acid for lysine 156 influenced autolytic function. The molecular docking simulation results indicated the appropriate binding of the substrate to the ocriplasmin variants with high-to-low affinities. The binding affinity of the wild-type variant for the substrate was higher than that between the mutant variants and the substrate. Simulation analyses, consisting of the root-mean-square deviation, the root-mean-square fluctuation, and the center-of-mass average distance showed a higher affinity of the substrate for the wild type than for the mutant variants.Conclusion: The mutational analysis of ocriplasmin revealed that A59T and K156E mutagenesis could be used for the development of a new variant with higher therapeutic efficacy.

Is pseudoexfoliation syndrome associated with vitreoretinal interface abnormalities?

To evaluate vitreoretinal interface abnormalities in patients with pseudoexfoliation (PEX) syndrome. This case-control study was performed in 136 patients diagnosed with unilateral PEX (PEX group) and 139 age- and sex-matched healthy volunteers (Control group). Both the affected and contralateral eyes were evaluated in the PEX group and the right eye was evaluated in the Control group. Vitreoretinal interface abnormalities and posterior vitreous detachment (PVD) were evaluated on optical coherence tomography (OCT) examination. The incidences of incomplete and complete PVD were significantly higher in the affected than contralateral eye in the PEX group and in the right eye in the Control group (P = 0.009, P = 0.012 and P = 0.004, P = 0.017, respectively). The rates of 'no PVD' were significantly higher in the contralateral eye in the PEX group and the Control group compared to the affected eye in the PEX group (P = 0.003 and P = 0.001, respectively). The odds ratio for incomplete PVD was 3.1 in PEX eyes compared to the contralateral eye in the PEX group and 3.9 compared to the Control group. The rate of epiretinal membranes (ERMs) in the affected eye was significantly different from the contralateral eye in the PEX and Control groups (P < 0.001 and P < 0.001, respectively). The odds ratio for ERM in PEX eyes was 3.51 compared to the contralateral eye in the PEX group and 4.23 compared to the Control group. In the presence of incomplete PVD, the odds ratio for ERM development was 3.81 in PEX eyes. We detected high rates of ERMs and incomplete PVD in patients with PEX. It is important to evaluate and follow up PEX cases in terms of vitreoretinal interface abnormalities.

Posterior vitreous detachment in patients with diabetes mellitus.

To compare the progression of posterior vitreous detachment (PVD) during aging among eyes of diabetics with diabetic retinopathy (DR), eyes of diabetics without DR, and eyes of nondiabetics. Prospective cross-sectional study. One-hundred thirty-three diabetic eyes with DR (DR group), 254 diabetic eyes without DR (non-DR group), and 577 nondiabetic eyes (nondiabetic group) were divided into four age categories: 1) 40-49 years, 2) 50-59 years, 3) 60-69 years, and 4) 70-79 years. The PVD state was examined using swept source-optical coherence tomography and classified into five stages: 0 (non PVD), 1 (paramacular PVD), 2 (perifoveal PVD), 3 (vitreofoveal separation), and 4 (complete PVD). The PVD stage significantly progressed in the DR, non-DR, and nondiabetic groups (p <0.0001). At 40-49 and 50-59 years, the PVD stage did not differ significantly among the three groups. At 60-69 and 70-79 years, the PVD stage was significantly less progressed in the DR than the non-DR and nondiabetic groups (p ≤0.0027), and did not differ significantly between the non-DR and nondiabetic groups. At 70-79 years, complete PVD was detected in 40.6% of eyes in the DR group, 69.6% in the non-DR group, and 73.5% of eyes in the nondiabetic group. PVD progresses later in diabetic eyes with DR than in diabetic eyes without DR and nondiabetics eyes at 60 and 70 years of age, suggesting a stronger vitreomacular adhesion in diabetics with DR.

Degradation of Contrast Sensitivity Function Following Posterior Vitreous Detachment

To evaluate the effect of posterior vitreous detachment (PVD) on contrast sensitivity function (CSF) in previously normal eyes, with the hypothesis that PVD reduces CSF. Prospective observational case series. At a single clinical practice 28 eyes were evaluated: 8 eyes of 8 adults (mean age 54.4 ± 10.1 years; range 39-68 years) with normal CSF documented by Freiburg Acuity Contrast Testing (Weber index: %W) who subsequently experienced PVD, as confirmed by ultrasonography and optical coherence tomography; 8 fellow eyes without PVD; and 12 control eyes: 9 eyes with PVD in patients who chose observation and 3 fellow eyes without PVD. At study entry there was no significant difference in CSF of fellow eye controls (mean 1.44 ± 0.27 %W; range 1.06-2.00 %W) and eyes that subsequently developed PVD (1.81 ± 0.61 %W; P= .146; range 1.01-2.69 %W). Following PVD there was a 52.5% reduction in CSF (2.76 ± 0.30 %W; P= .001; range 2.25-3.14 %W). CSF in the patients who chose limited vitrectomy (2.51 ± 0.46 %W; range 2.03-3.06 %W) was 41.8% worse than in the eyes with PVD of patients who chose observation (1.46 ± 0.21 %W; P= .001; range 1.08-1.87 %W). After vitrectomy, CSF improved by an average of 43.2%, normalizing in each case at 1month (CSF 1.51 ± 0.28 %W; P= .001; range 1.14-2.00 %W), 3months (1.38 ± 0.10 %W; P= .0002; range 1.28-1.51 %W), and 12months (1.34 ± 0.34 %W; P= .0001; range 1.01-1.89 %W, n= 5) postoperatively, attaining the same CSF as the control fellow eyes (1.34 ± 0.20 %W; range 1.06-1.56 %W). PVD is associated with significant reduction in CSF of previously normal eyes. This quantifiable negative impact on visual function can distinguishpatients who are not significantly bothered by vitreous floaters from those with clinically significant symptoms.

Vitreomacular Interface after Anti–Vascular Endothelial Growth Factor Injections in Neovascular Age-Related Macular Degeneration

To evaluate the incidence of posterior vitreous detachment (PVD) induced by intravitreal injections of anti-vascular endothelial growth factor (VEGF) agents in cases of neovascular age-related macular degeneration (AMD). Cohort study conducted at a single tertiary referral vitreoretinal practice. A total of 396 eyes of 295 patients were diagnosed with neovascular AMD between 2009 and 2014. A total of 125 eyes of 112 patients met the inclusion criteria and were evaluated in this study. This study included patients with neovascular AMD who presented vitreomacular adhesion (VMA) detected by spectral-domain optical coherence tomography (OCT) at baseline. Eyes with VMA were classified according to the diameter of vitreous attachment to the macular surface measured by OCT, with attachment of ≤1500 μm defined as focal and attachment of >1500 μm defined as broad. All patients received at least 3 monthly intravitreal injections of anti-VEGF agents. Follow-up visits were performed 1 month after each intravitreal injection and included OCT analysis to evaluate the incidence of PVD. Posterior vitreous detachment induced by anti-VEGF injections. The mean follow-up period was 21.3 months (range, 3-59 months). The mean number of intravitreal injections was 8.3 (range, 3-29 injections). Intravitreal drugs used in the study were ranibizumab (51.5%), bevacizumab (33.5%), and aflibercept (15.0%). Seven eyes (5.6%) developed PVD after intravitreal drug injection (3 eyes after the first intravitreal injection: bevacizumab in 1 and ranibizumab in 2; 2 eyes after the second injection: ranibizumab in 1 and bevacizumab in 1; 1 eye after the fourth injection: ranibizumab; and 1 eye after the sixth injection: aflibercept). A total of 118 eyes remained with persistent VMA. All 7 eyes that developed PVD were classified as having focal VMA, with the diameter of vitreous attachment ranging from 210 to 1146 μm (mean, 600 μm). Intravitreal injections of commonly used anti-VEGF intravitreal drugs rarely induce PVD in patients with neovascular AMD. Eyes with focal VMA have a greater chance to develop PVD than eyes with a broad area of VMA.

Reply to Grzybowski and Ascaso

Sir, We thank Drs Grzybowski and Ascaso1 for their interest in and comments on our recent article.2 We agree that in our paper there is a lack of details concerning the statistical tests used (which were omitted for the sake of brevity). In the study, we proved that each variable group was normally distributed using the Kolmogorov-Smirnov normality test. Then we applied the ANOVA for repeated measures test, which best fitted for our analysis. Please note, the Kruskal-Wallis test is valuable only for a two-group comparison. We also agree that the lack of a control group is crucial, and this was acknowledged as a limitation of our study. We also acknowledged the unmasked design of the study as a limitation of our analysis. Regarding the evaluation of posterior hyaloid peeling, our method to describe the intrasurgical findings has been already published by Azzolini et al3 in a study investigating autologous plasmin enzyme for diabetic macular oedema, and, to our knowledge, no other classification systems are available in the literature. In the conclusion section, we stated that a single intravitreal autologous plasmin enzyme injection seemed to be insufficient to induce a complete posterior vitreous detachment in patients affected by focal vitreomacular traction syndrome, as in our case series, we did not obtain any complete posterior vitreous detachment with a single injection. We thank the authors for the opportunity to clarify this important aspect, which we do not find contradictory. As per our ethical committee approved protocol (reported in the Methods section), we were allowed to perform just one single intravitreal injection for each study patient, with a 24-hour waiting time before vitrectomy. Although we could not ascertain if a greater time gap could have influenced the rate of posterior vitreous detachment occurrence, we remarked that the single injection appeared as a useful tool in vitreoretinal surgery by obtaining an easier-to-peel posterior hyaloid. Finally, during the revision process of our paper, we preferred to exclude the comparison of our results with the MIVI-IIT study,4 as the MIVI-IIT study has a very different study design and uses a different drug. Particularly, we believe that our impossibility (per protocol) to re-inject patients preclude any comparison between the two studies.

INTRAVITREAL TISSUE PLASMINOGEN ACTIVATOR TO TREAT REFRACTORY DIABETIC MACULAR EDEMA BY INDUCTION OF POSTERIOR VITREOUS DETACHMENT

To evaluate the effects of intravitreal injection of recombinant tissue plasminogen activator (TPA) for the treatment of refractory diabetic macular edema. A total of 27 patients with refractory diabetic macular edema with no evidence of posterior vitreous detachment were randomly assigned into follow-up (F/U) or TPA treatment groups. To control for the effects of intravitreal injection, an additional 14 patients with diabetic macular edema who were candidates for first-time intravitreal bevacizumab injection were enrolled as the IVB group. For the TPA and IVB groups, 25 μg of TPA or 1.25 mg of bevacizumab, respectively, were intravitreally injected. Fundoscopy, optical coherence tomography, and B-scan ultrasonography were performed at 1 week, 1 month, and 3 months after initiation of the study. The incidence of posterior vitreous detachment in fundoscopy over the follow-up period was 69.2% in the TPA group, which was significantly higher than that of the F/U and IVB groups (P = 0.001). Best-corrected visual acuity and changes in macular thickness did not significantly differ between the TPA and F/U groups over the 3-month period. Intravitreal TPA injection induces posterior vitreous detachment in patients with diabetic macular edema refractory to standard treatment but has no effect on macular thickness or best-corrected visual acuity within 3 months.

Intraoperativ festgestellte Häufigkeit der hinteren Glaskörperabhebung bei Patienten mit einer idiopathischen epiretinalen Membran

The prevalence of a posterior vitreous detachment in patients with an idiopathic epiretinal membrane is often exaggerated in the literature. This may make the surgeon become overconfident during vitrectomy. 34 patients with an idiopathic epiretinal membrane (mean age 72.9 years) were vitrectomised. The membrane and with it the remaining vitreous were stained with Membrane Blue. The preoperative visual acuity was -0.6 +/- 0.176 logMar units. Visual acuity increased postoperatively to -0.3 +/- 0.252 logMar units after 372.6 days. A posterior vitreous detachment was found in 17 patients (50 %), whereas there was none in the remaining 50 %. There was no correlation between age and prevalence of vitreous detachment. The increase in visual acuity was very encouraging. In contrast to reports in the older literature one cannot expect to find a posterior vitreous detachment in patients with an idiopathic epiretinal membrane. This can be checked intraoperatively very easily with Membrane Blue. Such a check becomes more urgent as the posterior vitreous detachment cannot be achieved with 23-G vitrectomy as easily as with 20-G vitrectomy.

Induction of posterior vitreous separation using LASIK suction ring may have a potential role in the management of diabetic macular edema

A significant percentage of patients with diabetic macular edema respond poorly to conventional laser photocoagulation. One associated factor in such patients with refractory diabetic macular edema is the absence of posterior vitreous detachment (PVD). Several invasive methods, such as surgical induction of PVD result in resolution of macular edema and improvement in visual acuity. Being invasive such modalities may have important surgical risks, such as retinal detachment and endophthalmitis. Recently, laser in situ keratomeilusis (LASIK), a well-accepted refractive procedure, has been reported to produce posterior vitreous detachment in patients with myopia. We herein hypothesize that application of LASIK suction ring, an external procedure, may be useful in the induction of PVD in patients with refractory diabetic macular edema and may have a better safety profile.

Intravitreal triamcinolone acetonide for treatment of intraocular oedematous and neovascular diseases

Intravitreal triamcinolone acetonide (IVTA) has increasingly been applied as treatment for various intraocular neovascular and oedematous diseases. Comparing the various diseases with respect to effect and side-effects of the treatment, the best response in terms of gain in visual acuity (VA) has been achieved for intraretinal oedematous diseases such as diffuse diabetic macular oedema, branch retinal vein occlusion, central retinal vein occlusion and pseudophakic cystoid macular oedema. In eyes with various types of non-infectious uveitis, including acute or chronic sympathetic ophthalmia and Adamantiadis-Behcet's disease, VA increased and the degree of intraocular inflammation decreased. Some studies have suggested that intravitreal triamcinolone may be useful as angiostatic therapy in eyes with iris neovascularization and proliferative ischaemic retinopathies. Intravitreal triamcinolone may possibly be helpful as adjunct therapy for exudative age-related macular degeneration (AMD), particularly in combination with photodynamic therapy. In eyes with chronic, therapy-resistant ocular hypotony, intravitreal triamcinolone can induce an increase in intraocular pressure (IOP) and may stabilize the eye. The complications of intravitreal triamcinolone therapy include: secondary ocular hypertension in about 40% of the eyes injected; medically uncontrollable high IOP leading to antiglaucomatous surgery in about 1-2% of the eyes; posterior subcapsular cataract and nuclear cataract leading to cataract surgery in about 15-20% of elderly patients within 1 year of injection; postoperative infectious endophthalmitis occurring at a rate of about one per 1000; non-infectious endophthalmitis, perhaps due to a reaction to the solvent agent, and pseudo-endophthalmitis with triamcinolone acetonide crystals appearing in the anterior chamber. Intravitreal triamcinolone injection can be combined with other intraocular surgeries, including cataract surgery, particularly in eyes with iris neovascularization. Cataract surgery performed some months after the injection does not show a markedly elevated complication rate. The injection may be repeated if the resultant benefits decrease after the initial IVTA injection. In non-vitrectomized eyes, the duration of the effect and side-effects of a single intravitreal injection of triamcinolone is about 6-9 months for a dosage of about 20 mg, and about 2-4 months for a dosage of 4 mg. So far, it has remained unclear whether the solvent agent should be removed, and if so, how.

A New Technique for Separation of Posterior Vitreous in Vitreous Surgery

To describe a new and effective technique, hydroseparation, for use in detaching the posterior cortical vitreous from the retina by the simple injection of fluid into the subhyaloid space. This technique was used in 7 eyes of 6 patients with diabetic retinopathy who had limited posterior vitreous detachment. Following core vitrectomy, a 32 gauge cannula was inserted into the subhyaloid space and a balanced salt solution (BSS) was injected. The injected fluid spread easily to the periphery, causing the vitreous cortex to be smoothly separated, except for areas with firm vitreoretinal adhesion. In those areas, we also used microscissors to separate the tissue. No iatrogenic retinal break occurred in any case. This simple technique, which exerts minimal traction force on the retina, was safe and useful for inducing posterior vitreous detachment in patients with diabetes.

Ocular Conditions Associated With Posterior Vitreous Detachment in Young Patients

To investigate the ocular conditions associated with posterior vitreous detachment (PVD) in young patients. The vitreous conditions of 861 patients younger than 30 years were studied retrospectively and examined biomicroscopically. In the first and second decades of life, retinitis pigmentosa, nondiabetic retinal vascular disorders, and a history of ocular contusion were most commonly associated with PVD. In the third decade of life, proliferative diabetic retinopathy was overwhelmingly the condition most commonly associated with PVD. This study delineated the ocular pathologic conditions associated with PVD in young patients. These findings may be useful in the management of PVD in patients younger than 30 years.