Posterior Vitreous Detachment

Degradation of Photopic and Mesopic Contrast Sensitivity Function in High Myopes With Partial Posterior Vitreous Detachment

Purpose

The purpose of this study was to evaluate the effects of posterior vitreous detachment (PVD) on visual quality in patients with high myopia, as well as investigate the associated factors of photopic and mesopic contrast sensitivity function (CSF) in high myopia.

Methods

Visual quality was comprehensively assessed in patients with high myopia. Visual acuity, contrast sensitivity (CS) at four spatial frequencies (3, 6, 12, and 18 cycles per degree [c.p.d.]) under photopic and mesopic conditions, as well as the modulation transfer function cutoff value (MTFcutoff), the objective scatter index (OSI), the Strehl ratio (SR), and internal aberrations, were measured in this cross-sectional study.

Results

This study included 94 eyes from 47 subjects with bilateral high myopia, including 23 eyes with complete PVD (cPVD), 21 eyes with partial PVD (pPVD), and 50 eyes without PVD (nPVD). There was no significant difference in visual quality between the cPVD group and the nPVD group. Whereas in eyes with pPVD, there was a degradation of overall photopic CSF (versus nPVD, P = 0.048), photopic CS at 3 c.p.d. (versus cPVD, P = 0.009 and versus nPVD, P = 0.032), photopic CS at 18 c.p.d. (versus nPVD, P = 0.033), overall mesopic CSF (versus nPVD, P = 0.033), and secondary astigmatism (versus cPVD, P = 0.044). Under photopic conditions, the factors affecting CSF were pPVD and SR, whereas the factors affecting mesopic CSF were pPVD, OSI, and ganglion cell-inner plexiform layer thickness.

Conclusions

The pPVD impaired visual quality in patients with high myopia compared to nPVD or cPVD, and pPVD could be a factor explaining CSF at both photopic and mesopic illumination.

Translational Relevance

Clinicians need to closely monitor patients with high myopia with pPVD due to the potential decline in visual quality and the development of vitreoretinal disorders.

Impact of posterior vitreous detachment on visual acuity after the implantation of a diffractive multifocal intraocular lens

PURPOSE

To investigate the effect of posterior vitreous detachment (PVD) on visual acuity (VA) after implantation of a diffractive multifocal intraocular lens (mIOL).

SETTING

Eye Clinic, Okayama, Japan.

DESIGN

Retrospective case series.

METHODS

This study evaluated 475 eyes of 475 patients who underwent cataract surgery with a TECNIS Multifocal ZLB00 lens implant between November 2017 and October 2019. Patient eyes were classified into the complete PVD group (PVD group) or the control group with no PVD/partial PVD (non-PVD group) and divided into 3 age categories: 65 to 69, 70 to 74, and 75 to 79 years. The postoperative VA of the PVD and non-PVD groups was compared between and within groups by age.

RESULTS

Distance-corrected near VA (DCNVA) was significantly worse in the PVD group than in the non-PVD group in all age categories ( P ≤ .029). In the PVD group, both corrected distance VA (CDVA) and DCNVA were significantly worse in the 75 to 79 years age group than in the 65 to 69 and 70 to 74 years age groups ( P ≤ .034). CDVA and DCNVA in the non-PVD group did not differ significantly between age categories.

CONCLUSIONS

The results of this study suggest that complete PVD worsens near VA in eyes with a diffractive mIOL. Furthermore, eyes with complete PVD may show an age-related decline in both CDVA and DCNVA. In particular, eyes ≥75 years of age with complete PVD have a poor visual prognosis and should be given careful consideration when deciding whether to implant a diffractive mIOL.

Retinal complications post posterior chamber phakic intraocular lens implantation at a tertiary eye hospital in the Eastern Province of Saudi Arabia

PURPOSE

Phakic intraocular lenses treat higher degrees of myopia not possible previously with conventional refractive surgery. The aim of this study is to report the incidence and risk factors of retinal complications after posterior chamber PIOL implantation and assess the differences in biometric parameters between patients who developed such complications versus those who did not.

METHODS

This retrospective study recruited 514 patients who underwent ICL implantation to correct myopia at a tertiary eye hospital center in the Eastern province of Saudi Arabia. Follow up period was at least one year. Medical records of the patients were reviewed to obtain the required data. Associations between respondents' characteristics and retinal complications were evaluated using the Chi-squared test.

RESULTS

The mean (SD) age was 27.7 (± 6.5) years ranging from 18 to 47. Laser treatment was performed in 14 cases (2.7%). Retinal complications occurred in six cases (1.2%). The risk of retinal complication was significantly higher among patients with high axial length (OR = 1.3, 95% CI 1.2, 1.4) and patients with high pre-spherical equivalent before ICL (OR = 1.09, 95% CI 1.03, 1.4).

CONCLUSION

Patients with higher axial length and higher pre-spherical equivalent before ICL implantation are at high risk of retinal complications.

A modified 23-G trocar and cannula system with lateral micropores for drainage of vitreous humor

When primary angle-closure glaucoma occurs during an acute attack, routine phacoemulsification is challenging because of the high intra-ocular pressure (IOP) and shallow anterior chamber (AC). To reduce IOP and deepen the AC before phacoemulsification, a portion of the vitreous body is often removed. In this report, we introduce an extended trocar/cannula system with lateral micropores to drain the liquid vitreous before routine phacoemulsification to solve this problem. A modified trocar was used to drain the liquefied vitreous before routine phacoemulsification. We demonstrated that this novel trocar/cannula system is safe and effective for draining liquefied vitreous before routine phacoemulsification. It also facilitates the transition to smooth phacoemulsification.

Investigating the associations of macular edema in retinitis pigmentosa

Macular edema (ME), the accumulation of intraretinal fluid in the macula, is a common sight affecting sequelae of retinitis pigmentosa (RP). However, it is unclear why some patients develop ME, and others do not. This study aims to identify associations between clinical-genetic factors in RP with ME. Patients with clinically confirmed RP cases were identified from the inherited retinal disease database at a large tertiary referral academic center. Demographic and genetic testing findings were noted. Additionally, optical coherence tomography volume scans were graded using a validated grading system. One hundred and six patients (73.1%) were found to have ME in at least one eye (OD = 88, mean = 37.9%, OS = 98, mean = 31.7%). Structurally, the presence of epiretinal membrane (ERM) (p < 0.007) and vitreo-macular traction (VMT) (p < 0.003) were significantly associated with ME. Additionally, X-linked (p < 0.032) and autosomal dominant inheritance (p < 0.039) demonstrated a significant association with ME, with RP1 (p < 0.045) and EYS (p < 0.017) pathogenic variants also significantly associated with ME. This study, in a large cohort of RP patients, confirms previous retinal structural associations for ME in RP and identifies potential new genetic associations.

RECURRENT FLOATERS AFTER LIMITED VITRECTOMY FOR VISION DEGRADING MYODESOPSIA

PURPOSE

Limited vitrectomy improves vision degrading myodesopsia, but the incidence of recurrent floaters postoperatively is not known. We studied patients with recurrent central floaters using ultrasonography and contrast sensitivity (CS) testing to characterize this subgroup and identify the clinical profile of patients at risk of recurrent floaters.

METHODS

A total of 286 eyes (203 patients, 60.6 ± 12.9 years) undergoing limited vitrectomy for vision degrading myodesopsia were studied retrospectively. Sutureless 25G vitrectomy was performed without intentional surgical posterior vitreous detachment (PVD) induction. CS (Freiburg Acuity Contrast test: Weber index, %W) and vitreous echodensity (quantitative ultrasonography) were assessed prospectively.

RESULTS

No eyes (0/179) with preoperative PVD experienced new floaters. Recurrent central floaters occurred in 14/99 eyes (14.1%) without complete preoperative PVD (mean follow-up = 39 months vs. 31 months in 85 eyes without recurrent floaters). Ultrasonography identified new-onset PVD in all 14 (100%) recurrent cases. Young (younger than 52 years; 71.4%), myopic (≥-3D; 85.7%), phakic (100%) men (92.9%) predominated. Reoperation was elected by 11 patients, who had partial PVD preoperatively in 5/11 (45.5%). At study entry, CS was degraded (3.55 ± 1.79 %W) but improved postoperatively by 45.6% (1.93 ± 0.86 %W, P = 0.033), while vitreous echodensity reduced by 86.6% ( P = 0.016). New-onset PVD postoperatively degraded CS anew, by 49.4% (3.28 ± 0.96 %W; P = 0.009) in patients electing reoperation. Repeat vitrectomy normalized CS to 2.00 ± 0.74%W ( P = 0.018).

CONCLUSION

Recurrent floaters after limited vitrectomy for vision degrading myodesopsia are caused by new-onset PVD, with younger age, male sex, myopia, and phakic status as risk factors. Inducing surgical PVD at the primary operation should be considered in these select patients to mitigate recurrent floaters.

[Age-related changes in human vitreous]

There are two main age-related changes that can occur in the vitreous body of healthy individuals throughout life: liquefaction (synchesis) and aggregation of collagen fibrils into dense bundles (syneresis). Progressive age-related degradation leads to posterior vitreous detachment (PVD). At present many classifications of PVD exist, in which authors relied either on the morphological features, or on the differences in pathogenesis before and after widespread use of OCT. The course of PVD can be either normal or anomalous. Physiological PVD induced by age-related vitreous changes progresses in specific stages. The review emphasizes that PVD can occur initially not only in the central zone of the retina, but also on the periphery with further spread to the posterior pole. Anomalous PVD can lead to various negative effects on the retina, as well as on the vitreous as a result of traction in the area of vitreoretinal interface.

Vitreous Substitutes as Drug Release Systems

Vitreous substitutes are traditionally used to stabilize the retina after vitrectomy. In recent years, various approaches have been developed for using the vitreous substitute not only as a tamponade but also as a drug release system to tackle ocular diseases. This review provides an overview of the requirements for vitreous substitutes and discusses the current clinically applied as well as novel polymer-based vitreous substitutes as drug delivery systems, including their release mechanisms, efficiencies, challenges, and future perspectives.

Prevalence and predictive factors for posterior vitreous attachment in eyes undergoing epiretinal membrane surgery

BACKGROUND

To report the prevalence of posterior vitreous attachment (PVA) in patients with idiopathic epiretinal membrane (iERM) and to determine associated preoperative predictive factors.

METHODS

Retrospective observational case series of 408 eyes who underwent surgery for iERM without vitreomacular traction. The status of the posterior hyaloid was assessed intraoperatively. Predictive factors were analysed using univariate and multivariate logistic regression. We also evaluated the effect of PVA on the anatomical and functional outcomes of surgery.

RESULTS

Eighty-two (20.1%) eyes were found to have an undetached posterior hyaloid during vitrectomy. In multivariate analysis, axial length (AL) and lens status were strongly associated with the posterior vitreous status (p = 0.031 and p = 0.048). The odds of having a PVA decreased by a factor 0.81 per mm of AL (95% CI, 0.66-1.00). Phakic eyes had a 2.88-fold increased risk of exhibiting PVA compared to those with previous cataract extraction (95% CI, 1.10-7.52). The presence of PVA did not have any effect on postoperative anatomical and functional outcomes. In contrast, we found that eyes with shorter axial length, low preoperative visual acuity and disruption of the ellipsoid zone exhibited worse visual recovery (p = 0.006, p < 0.001 and p = 0.037).

CONCLUSION

PVA was observed in 20.1% of eyes undergoing vitrectomy for iERM. Shorter AL and phakic status were strong predictive factors of PVA in those eyes. However, the morphological features and the surgical prognosis of iERMs with PVA did not differ from those with posterior vitreous detachment.

Comparison of Posterior Hyaloid Assessment Using Preoperative Optical Coherence Tomography and Intraoperative Triamcinolone Acetonide Staining During Vitrectomy

Purpose

To compare the specificity of diagnosing posterior vitreous detachment (PVD) using preoperative optical coherence tomography (OCT) versus intraoperative triamcinolone acetonide (TA) staining in patients undergoing vitrectomy.

Patients and Methods

This retrospective cohort study included patients undergoing pars plana vitrectomy for diverse retinal pathologies. Intraoperatively, surgeons evaluated the posterior hyaloid status with TA staining and compared it with preoperative OCT findings.

Results

One hundred six patients underwent intraoperative assessments of posterior hyaloid status, with 72% (76/106) of the eyes showing positive staining. Sixty-two patients had also undergone preoperative OCT. Of the patients diagnosed with PVD on preoperative OCT, 50% (15/30) showed positive TA staining intraoperatively. The sensitivity of preoperative OCT assessment was 83.3%, and its specificity was 65.9%.

Conclusion

Preoperative OCT imaging is associated with lower sensitivity and specificity for diagnosing PVD when compared to intraoperative TA staining.

Indications and outcomes for intravitreal injection of C3F8 gas for symptomatic vitreomacular traction

To evaluate the indications and outcomes of perfluoropropane (C3F8) gas injection for symptomatic vitreomacular traction (VMT). A retrospective analysis of eyes with VMT treated with 0.3 mL of C3F8 gas was performed. Patients were not asked to posture after gas injection. In phakic patients, cataract surgery was performed simultaneously. Patients were examined after one week and one month postoperatively. Twenty-nine consecutive eyes of 26 patients with symptomatic VMT who underwent pneumatic vitreolysis were included. A complete posterior vitreous detachment was achieved in 18 eyes (62.1%) after a single gas injection at the final visit. The rate of posterior vitreous detachment was reduced significantly with the presence of epiretinal membrane (ERM) (p = 0.003). Three eyes formed a macular hole (MH) postoperatively and another eye developed a retinal detachment. Mean visual acuity increased significantly after one month (p < 0.008). Pneumatic vitreolysis is a viable option for treating VMT with few adverse events. Patient with concomitant ERM had a significantly lower success rate.

Vitreous Structure and Visual Function in Myopic Vitreopathy Causing Vision-Degrading Myodesopsia

PURPOSE

Myopic vitreopathy features precocious fibrous vitreous liquefaction and early posterior vitreous detachment (PVD). It is unclear whether visual function is affected by myopic vitreopathy and PVD. This study assessed the relationships among axial length, structural vitreous density, PVD, and visual function.

DESIGN

Retrospective case-control study.

METHODS

Ultrasonography measurements were made of axial length, logMAR VA, contrast sensitivity function (CSF [Freiburg acuity contrast test]), and quantitative B-scan ultrasonography.

RESULTS

Seventy-nine subjects (45 men and 34 women; mean age: 49 ± 14 years) were analyzed. Axial lengths ranged from 22 to 29.2 mm (mean: 24.9 ± 1.8 mm; myopic eyes: 26.35 ± 1.35 mm; and nonmyopic eyes: 23.45 ± 0.75 mm; P < .001). With increasing axial length there was greater vitreous echodensity (R: 0.573; P < .01) and degradation in CSF (R: 0.611; P < .01). Subgroup analyses found that myopic eyes (>- 3 diopters) had 37% more vitreous echodensity than nonmyopic eyes (762 ± 198 arbitrary units [AU] vs. 557 ± 171 AU, respectively; P < .001) and that CSF was 53% worse in myopic eyes (3.30 ± 1.24 Weber index [%W]) than in nonmyopic eyes (2.16 ± .59 %W; P < .001). Myopic eyes with PVD had 33% greater vitreous echodensity (815 ± 217 AU; P < .001) and 62% degradation in CSF (3.63 ± 2.99 %W) compared to nonmyopic eyes with PVD (613 ± 159 AU; 2.24 ± 0.69 %W; P < .001, each). Limited vitrectomy was performed in 11 of 40 cases (27.5%), normalizing vitreous echodensity and CSF in each case.

CONCLUSIONS

Axial myopia is associated with increased fibrous vitreous liquefaction and echodensity, as well as profound degradation of CSF. PVD in myopic eyes is associated with even more structural and functional abnormalities, normalized by limited vitrectomy. These findings may explain some common complaints of myopic patients with respect to vision and quality of life.

Polymeric hydrogels as a vitreous replacement strategy in the eye

Vitreous endo-tamponades are commonly used in the treatment of retinal detachments and tears. They function by providing a tamponading force to support the retina after retina surgery. Current clinical vitreous endo-tamponades include expansile gases (such as sulfur hexafluoride (SF₆) and perfluoropropane (C₃F₈)) and also sislicone oil (SiO). They are effective in promoting recovery but are disadvantaged by their lower refractive indices and lower densities as compared to the native vitreous, resulting in immediate blurred vision after surgery and necessitating patients to assume prolonged face-down positioning respectively. While the gas implants diffuse out over time, the SiO implants are non-biodegradable and require surgical removal. Therefore, there is much demand to develop an ideal vitreous endo-tamponade that can combine therapeutic effectiveness with patient comfort. Polymeric hydrogels have since attracted much attention due to their favourable properties such as high water content, high clarity, suitable refractive indices, suitable density, tuneable rheological properties, injectability, and biocompatibility. Many design strategies have been employed to design polymeric hydrogel-based vitreous endo-tamponades and they can be classified into four main strategies. This review seeks to analyse these various strategies and evaluate their effectiveness and also propose the key criteria to design successful polymeric hydrogel vitreous endo-tamponades.

Characteristics and outcomes of vitrectomy for proliferative diabetic retinopathy in young versus senior patients

Background

Proliferative diabetic retinopathy (PDR) is one of the most common cause of vision loss in diabetic patients, and the incidence age of PDR patients gradually gets younger. This study aims to compare the characteristics of PDR and outcomes following vitrectomy in young and senior patients.

Methods

This is a retrospective case series study. Data of 116 eyes of 92 patients who underwent vitrectomy for PDR from February 2012 to February 2017 were reviewed, which were divided into young and senior patient groups. All patients were followed up for 24 months at least.

Results

There were 62.1% of eyes with tractional retinal detachment secondary to PDR in the young patient group, while only 12.1% of eyes in the senior patient group with this surgery indication. (P < 0.001) The best corrected visual acuity increased in 41 eyes (70.7%), stable in 9 eyes (15.5%), and decreased in 8 eyes (13.8%) in young patients at the final follow-up. And it increased in 47 eyes (81.0%), stable in 2 eyes (3.4%), and decreased in 9 eyes (15.5%) in senior patients.(P = 0.085) Postoperative complications mainly included recurrent vitreous hemorrhage (24.1%), retinal detachment (3.4%), neovascular glaucoma (NVG) (27.6%) and nuclear sclerosis (53.4%) in young patients, and it was 19.0, 0.0, 1.7 and 3.4% in senior patients respectively.

Conclusion

PDR of young patients is more severe than that of senior patients, and vitrectomy is an effective and safe method for PDR treatment. NVG is a main and severe complication besides nuclear sclerosis in young patients, and the incidence of NVG is higher compared to that in senior patients.

Vitreous and Vision Degrading Myodesopsia

Macromolecules comprise only 2% of vitreous, yet are responsible for its gel state, transparency, and physiologic function(s) within the eye. Myopia and aging alter collagen and hyaluronan association causing concurrent gel liquefaction and fibrous degeneration. The resulting vitreous opacities and collapse of the vitreous body during posterior vitreous detachment are the most common causes for the visual phenomenon of vitreous floaters. Previously considered innocuous, the vitreous opacities that cause floaters sometimes impact vision by profoundly degrading contrast sensitivity function and impairing quality-of-life. While many people adapt to vitreous floaters, clinically significant cases can be diagnosed with Vision Degrading Myodesopsia based upon echographic assessment of vitreous structure and by measuring contrast sensitivity function. Perhaps due to the ubiquity of floaters, the medical profession has to date largely ignored the plight of those with Vision Degrading Myodesopsia. Improved diagnostics will enable better disease staging and more accurate identification of severe cases that merit therapy. YAG laser treatments may occasionally be slightly effective, but vitrectomy is currently the definitive cure. Future developments will usher in more informative diagnostic approaches as well as safer and more effective therapeutic strategies. Improved laser treatments, new pharmacotherapies, and possibly non-invasive optical corrections are exciting new approaches to pursue. Ultimately, enhanced understanding of the underlying pathogenesis of Vision Degrading Myodesopsia should result in prevention, the ultimate goal of modern Medicine.

Vitreous Antioxidants, Degeneration, and Vitreo-Retinopathy: Exploring the Links

The transparent vitreous body, which occupies about 80% of the eye’s volume, is laden with numerous enzymatic and non-enzymatic antioxidants that could protect the eye from oxidative stress and disease. Aging is associated with degeneration of vitreous structure as well as a reduction in its antioxidant capacity. A growing body of evidence suggests these age-related changes may be the precursor of numerous oxidative stress-induced vitreo-retinopathies, including vision degrading myodesopsia, the clinically significant entoptic phenomena that can result from advanced vitreous degeneration. Adequate intravitreal antioxidant levels may be protective against vitreous degeneration, possibly preventing and even improving vision degrading myodesopsia as well as mitigating various other vitreo-retinopathies. The present article is, therefore, a review of the different antioxidant molecules within vitreous and the inter-relationships between vitreous antioxidant capacity and degeneration.