Vitreoschisis

Human vitreous in proliferative diabetic retinopathy: Characterization and translational implications

Diabetic retinopathy (DR) is one of the leading causes of visual impairment in the working-age population. DR is a progressive eye disease caused by long-term accumulation of hyperglycaemia-mediated pathological alterations in the retina of diabetic patients. DR begins with asymptomatic retinal abnormalities and may progress to advanced-stage proliferative diabetic retinopathy (PDR), characterized by neovascularization or preretinal/vitreous haemorrhages. The vitreous, a transparent gel that fills the posterior cavity of the eye, plays a vital role in maintaining ocular function. Structural and molecular alterations of the vitreous, observed during DR progression, are consequences of metabolic and functional modifications of the retinal tissue. Thus, vitreal alterations reflect the pathological events occurring at the vitreoretinal interface. These events are caused by hypoxic, oxidative, inflammatory, neurodegenerative, and leukostatic conditions that occur during diabetes. Conversely, PDR vitreous can exert pathological effects on the diabetic retina, resulting in activation of a vicious cycle that contributes to disease progression. In this review, we recapitulate the major pathological features of DR/PDR, and focus on the structural and molecular changes that characterize the vitreal structure and composition during DR and progression to PDR. In PDR, vitreous represents a reservoir of pathological signalling molecules. Therefore, in this review we discuss how studying the biological activity of the vitreous in different in vitro, ex vivo, and in vivo experimental models can provide insights into the pathogenesis of PDR. In addition, the vitreous from PDR patients can represent a novel tool to obtain preclinical experimental evidences for the development and characterization of new therapeutic drug candidates for PDR therapy.

Vitreous and intraretinal macular changes in diabetic macular edema with and without tractional components

Diabetic macular edema (DME) is still one of the main causes of visual impairment. Repeated intravitreal injections of ranibizumab are considered the gold standard treatment, but the efficacy in patients with prominent cystic characteristics remains uncertain. In diabetic retinas, the identification of both antero-posterior and, particularly, tangential tractions is crucial to prevent misdiagnosis of tractional and refractory DME, and therefore to prevent poor treatment outcomes. The treatment of tractional DME with anti-VEGF injections could be poorly effective due to the influence of a tractional force. Pars plana vitrectomy (PPV) is a surgical procedure that has been widely used in the treatment of diffuse and refractory DME. Anatomical improvement, although stable and immediate, did not result in visual improvement. PPV with internal limiting membrane (ILM) peeling for the treatment of non-tractional DME in patients with prominent cysts (> 390 μm) causes subfoveal atrophy, defined as "floor effect". Epiretinal tangential forces and intraretinal change evaluation by SD-OCT of non-tractional DME are essential for determining appropriate management.

Vitreoretinal Interface Characteristics in Eyes with Idiopathic Macular Holes: Qualitative and Quantitative Analysis

Objectives

To determine the qualitative and quantitative vitreoretinal interface characteristics with spectral domain optical coherence tomography (SD-OCT) in eyes with macular hole (MH) and investigate their relation with best corrected visual acuity (BCVA) and MH duration.

Materials and Methods

Sixty-one eyes of 46 consecutive patients diagnosed with idiopathic MH were included in the study. The mean age of the patients was 66.7±7.5 (51-79) years. Complete ophthalmologic examination and SD-OCT examination were performed in all eyes and MH stages were determined according to SD-OCT findings. Qualitative characteristics of the vitreoretinal interface were investigated, including vitreomacular traction, vitreopapillary traction, maculopapillary traction, vitreoschisis, intraretinal cyst, presence of epiretinal membrane, and the integrity of the photoreceptor inner segment-outer segment junction (IS/OS) and external limiting membrane (ELM). In addition, MH diameter, MH base diameter (MHBD), ELM defect diameter, IS/OS defect diameter, and MH height were quantitatively measured and the MH index was calculated.

Results

Out of 61 eyes, 9.8% were classified as stage 1a, 19.7% as stage 1b, 18% as stage 2, 23% as stage 3, and 29.5% as stage 4. Mean BCVA was 0.28±0.24 (1 mps-1.0) Snellen and MH duration was 10.08±18.6 (1-108) months. The most common interface characteristics associated with MH were determined as intraretinal cyst (91.8%), IS/OS defect (78.7%) and ELM defect (63.9%). Duration and stage of MH were inversely proportional to BCVA but directly proportional to the presence and diameter of IS/OS and ELM defects. BCVA was significantly lower in eyes with IS/OS and ELM defects (p<0.0001; p<0.0001 Mann-Whitney U test).

Conclusion

We determined that the most important factors affecting BCVA in cases with idiopathic MH were MH stage, MH duration, MHBD, and the presence and diameter of IS/OS and ELM defects, which suggests that these parameters should be considered while making decisions about prognosis and treatment.

Evaluation of hyaloid-retinal relationship during triamcinolone-assisted vitrectomy for primary rhegmatogenous retinal detachment

AIMS

To determine hyaloid-retinal relationship in primary rhegmatogenous retinal detachment during vitreous surgery.

METHODS

This is a prospective, interventional study of patients (n = 72) undergoing triamcinolone-assisted 25G vitreous surgery for primary rhegmatogenous retinal detachment. Hyaloid-retinal relationship was noted intraoperatively to identify regions and patterns of firm attachment and was classified into subgroups. Analysis was done to determine association between hyaloid-retinal relationship patterns and preoperative findings: posterior vitreous detachment, proliferative vitreoretinopathy, type of retinal tear, the presence of peripheral degenerations, and postoperative outcomes.

RESULTS

Three patterns of hyaloid-retinal relationship were identified: type1 (complete absence of posterior vitreous detachment (21%)), type 2 (incomplete posterior vitreous detachment (47%)) and type 3 (complete posterior vitreous detachment (32%)). Posterior vitreous detachment in some form was present in 84% of the cases with retinal tears as the causative break but none of the cases with retinal holes (p < 0.001). None of the cases with vitreoretinal degeneration had complete posterior vitreous detachment (p = 0.001). 69% of proliferative vitreoretinopathy-C cases had type 1 hyaloid-retinal relationship as compared to 11% cases with no proliferative vitreoretinopathy (p < 0.001). Proliferative vitreoretinopathy-related anatomical failure was seen in 7.5%, and 80% of these eyes with recurrent RD had type 1 hyaloid-retinal relationship (p<0.001). Nearly half the patients diagnosed as complete posterior vitreous detachment preoperatively were found to have incomplete posterior vitreous detachment intraoperatively.

CONCLUSIONS

Majority of the cases with rhegmatogenous retinal detachment have some form of strong vitreoretinal adhesion. Hyaloid-retinal relationship varies with types of retinal breaks, retinal degeneration, and proliferative vitreoretinopathy. Intraoperative hyaloid-retinal relationship is frequently different from that assessed before surgery and the proposed classification may improve surgical decision making and prognostication.

POSTERIOR PRECORTICAL VITREOUS POCKETS IN HIGH MYOPIA OBSERVED BY ENHANCED VITREOUS IMAGING OF SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY

PURPOSE

To observe the vitreous in highly myopic eyes with posterior precortical vitreous pockets (PPVPs) using enhanced vitreous imaging of spectral domain optical coherence tomography.

METHODS

Fifty-two highly myopic eyes with PPVPs of 36 patients were included in this study. All subjects underwent enhanced vitreous imaging optical coherence tomography. The size of PPVPs was measured, and the frequency of imaging features was recorded.

RESULTS

Nine imaging features of the vitreous in highly myopic eyes with PPVPs were found. The average age of subjects was 38.1 ± 10.8 years. The mean height of PPVPs was 1,177 ± 704 μm, and the mean width was 7,440 ± 755 μm. Hyperreflective line and the interlayer were observed in 30 (57.7%) eyes. Hyperreflective dots were found in 37 (71.2%) eyes. More central vitreous space was more frequently detected in younger patients. Prevascular vitreous fissure was detected in 7 (13.5%) eyes. W-shaped cavity, identified as an empty space with a smooth W-shaped edge, was demonstrated to be the fusion of Cloquet's canal and the extension of PPVPs. Perpendicular hyperreflective parallel strands were detected in 3 (5.8%) eyes. Hyperreflective network was observed in 10 (19.2%) eyes. Hyperreflective parapapillary tubercle was found in 7 (13.5%) eyes.

CONCLUSION

Nine imaging features of the vitreous in highly myopic eyes with PPVPs were visualized by enhanced vitreous imaging optical coherence tomography.

TOMOGRAPHIC RELATIONSHIPS BETWEEN RETINAL NEOVASCULARIZATION AND THE POSTERIOR VITREOUS IN PROLIFERATIVE DIABETIC RETINOPATHY

PURPOSE

To describe anatomical relationships of retinal neovascular complexes (NVCs) and the posterior vitreous in proliferative diabetic retinopathy using spectral domain optical coherence tomography.

METHODS

Cross-sectional study. Neovascular complexes were imaged using spectral domain optical coherence tomography in 51 eyes of 37 patients. The relationship of NVCs to the posterior vitreous cortex and posterior vitreous spaces, such as the premacular bursa, prevascular vitreous fissures, and perimacular cisterns, was analyzed.

RESULTS

In the 77 NVCs evaluated, 61 (79%) had grown along the outer surface of the posterior hyaloid face, and vitreoschisis was present in 37 (48%). The "wolf's jaw" configuration was present in 9% and resulted from NVC arising from the arcades and proliferating along the posterior hyaloid face. By contrast, NVCs that invaded the bursa originated from smaller venous tributaries more distant from the arcades. The premacular bursa and prevascular vitreous fissure/perimacular cistern were invaded infrequently, respectively, in 15% and 38% (P = 0.137).

CONCLUSION

Tomographic analysis of diabetic NVCs showed that most NVCs arise and grow along the posterior hyaloid face and that vitreoschisis is more prevalent than what has been found in ultrasound studies. The wolf's jaw configuration does not seem to result from the invasion of the bursa, as previously suggested.

[A porous coral-like structure - a new insight into the morphology of the inner limiting membrane of the retina?]

To date, the internal limiting membrane (ILM), specifically, the side facing the retina, has never been studied by two parallel, mutually complementary methods. This is an attempt to explain favorable results of ILM peeling in various macular pathologies.

AIM

By employing scanning (SEM) and transmission electron microscopy (TEM), to identify morphological features of epiretinal samples removed during vitrectomy in patients with lamellar macular hole (LMH) or epiretinal membrane (ERM).

MATERIAL AND METHODS

We studied 23 eyes of 23 patients divided into two groups. The first group (13 samples, 11 eyes) consisted of patients with LMH; the second (12 samples, 12 eyes) - with ERM. The surgeries yielded a total of 21 epiretinal samples peeled simultaneously with the ILM and 4 epiretinal samples (2 eyes) peeled in two parts, the second part containing the ILM. One half of the samples was studied by SEM without prior dehydratation, the other - by TEM.

RESULTS

The study revealed a high degree of ultrastructural similarity between the two groups of ILM samples. Judging from SEM findings, two sides of the membrane were clearly identified. Porous coral-like structures (PCS) were discovered on the side facing the retina. TEM in the area of PCS discovered parallel arrangement of multiple Muller cell (MC) bodies and processes separated by wide layers of the intercellular matrix. The vitreal side of all ILM samples was notable for numerous fibroblast-like cells. Many variously shaped petrified structures were found on both sides of the membrane.

CONCLUSION

During the so called ILM peeling, the surgeon removes a layered structure that includes the basal membrane of MC, cells and fibers attached to its vitreal side, and one more layer comprised by PCS and rather readily torn off from the main massif. The functional significance of this previously unknown structure as well as the effect of its partial removal during surgical manipulations with neurosensory retina in the macular region is yet to be investigated.

Microarchitecture of the Vitreous Body: A High-Resolution Optical Coherence Tomography Study

PURPOSE

To report novel vitreous body microarchitecture findings using high-resolution spectral-domain optical coherence tomography (HR-SD-OCT).

DESIGN

Prospective, cross-sectional study.

METHODS

Horizontal and vertical retinal cross-sectional images that were 10 mm long were acquired from 17 eyes of 17 young healthy volunteers using HR-SD-OCT with enhanced vitreous imaging (EVI). Images were acquired through the fovea, upper vessel arcade, and lower vessel arcade.

RESULTS

Three new findings on vitreous body microarchitecture were found. First, material located between the retina and posterior vitreous cortex was easily detected in 90% of upper and lower vessel arcade scans. Most scans contained hyperreflective dots and multilayered hyperreflective lines around the detached vitreous cortex. Second, a lamellar structure was observed in the vitreous body in 70%-80% of all scans, excluding vertical scans of the upper arcade vessel area. Third, tubular zones of hypodensity were detected in >80% of scans, excluding horizontal scans of the macula. Interestingly, the location of tubular zones of hypodensity seemed to correspond with the location of retinal vessels. Subject age, refractive error, and axial length were not significantly different in scans with and without material between the retina and vitreous, lamellar structures, and tubular zones of hypodensity.

CONCLUSIONS

The microarchitecture of the vitreous body can be visualized using HR-SD-OCT and EVI.

Age-dependent vitreous separation from the macula in a clinic population

Background

Vitreous degeneration begins soon after birth and accelerates throughout life. Vitreous liquefaction with a slowly progressive separation of the posterior hyaloid from the peripheral macula usually leads to complete posterior vitreous detachment. The purpose of this study is to measure the age-related prevalence of partial vitreous separation and the length of residual vitreous adhesion in an ophthalmology clinic population.

Methods

Patients examined by the senior author (MWS) during a 6-month period were included in a retrospective chart review. Demographic data and spectral domain optical coherence tomography scan results were gathered. Data analysis with descriptive statistics focused on the prevalence and extent of partial vitreous separation.

Results

The mean age of the study patients was 69.9 years, and 62% were phakic. The highest prevalence of partial posterior hyaloid separation from the internal limiting membrane (71.2%) was seen in the 50- to 54-year age group. This prevalence rate steadily decreased to 5.6% in the 95- to 99-year age group. The prevalence of complete vitreous detachment as determined by slit-lamp biomicroscopy increased from 1.7% in the <50-year age group to a maximum of 29.2% in the 75- to 79-year group. The length of vitreomacular adhesion averaged 4.6 mm in the 50- to 54-year age group and steadily decreased to 2.1 mm in the 90- to 95-year group.

Conclusion

Vitreomacular separation affects the majority of eyes in the sixth decade of life. The prevalence of partial vitreous separation decreases with advancing age, probably because an increasing number of these patients progress to complete posterior vitreous detachment.

Intraretinal changes in the presence of epiretinal traction

BACKGROUND

To determine the correlation between the area of morphological changes on the macular surface, the depth of intraretinal changes and the best-corrected visual acuity (BCVA) in patients with idiopathic epiretinal membrane.

METHODS

In this prospective cross-sectional study, 38 patients underwent BCVA testing with a Snellen eye chart. The depth of traction, photoreceptor outer segment layer (PROS) thickness, central macular thickness (CMT) and presence of intraretinal cysts were measured using the Avanti RTVue XR and 3D Widefield Enface OCT instruments. Enface sections were performed at the inner limiting membrane (ILM) line level (ILM offset). Patients were categorized into two groups: in group 1 (n = 21), the depth of traction was within 90 μm from the ILM, and in group 2 (n = 17) it was beyond 90 μm from the ILM. The main outcome measure was the correlation between area of epiretinal traction and BCVA according to the depth of traction.

RESULTS

In group 1, the depth of traction was 55.15 ± 14.28 μm, the area of traction was 38.95 ± 13.63 mm², PROS thickness was 51.20 ± 7.23 μm, and CMT was 362.65 ± 41.08 μm. In group 2, the depth of traction was 112.24 ± 10.89 μm, the area of traction was 25.18 ± 4.07 mm², PROS thickness was 50.24 ± 9.01 μm, and mean CMT was 534.29 ± 126.81 μm. Statistically significant differences in depth of traction, area of traction and CMT were found between the two groups (P < 0.001). The relationship between structure and function between the area of traction and BCVA was better explained in group 2 (r = 0.814, P < 0.001).

CONCLUSIONS

We found that intraretinal changes were induced by the ERM, and varied according to the depth of traction measured with en face analysis. In the case of traction deeper than 90 μm, we found a significant correlation between the inner area of the epiretinal traction and BCVA. We believe that retinal stress induced by epiretinal traction is better characterized by combining information provided by sagittal and transverse OCT scans, thus defining its prognostic significance in ERM.

Quantifying Visual Dysfunction and the Response to Surgery in Macular Pucker

PURPOSE

To measure the effects of macular pucker (MP) on macular structure and quantify function by measuring visual acuity (VA), contrast sensitivity (CS), and distortions. The effects of surgery were quantitatively evaluated using these measures.

DESIGN

Prospective, comparative case series.

PARTICIPANTS

Fifty-three patients with unilateral MP and normal fellow eyes: 24 operated MP subjects, 17 unoperated controls, and 12 reproducibility subjects.

METHODS

Posterior vitreous detachment was diagnosed by ultrasound and ellipsoid zone disruption (EZD) was determined by OCT, which also measured macular thickness and volume. Vision was assessed, by measuring VA (logMAR) and CS (Freiburg acuity contrast testing: Weber index, %W). A visual distortions index (%DI) was calculated using 3-dimensional threshold Amsler grid testing. Comparisons to controls were performed before surgery and at 1, 3, 6, and 12 months after vitrectomy/membrane peel without chromodissection.

MAIN OUTCOME MEASURES

Posterior vitreous detachment (ultrasound), EZD (OCT), macular thickness and volume (OCT), VA (logMAR), CS (%W), distortions (%DI).

RESULTS

Posterior vitreous detachment was present in 90% of MP eyes, but only 50% of fellow eyes (P < 0.001). All structural and functional indices were worse (28% to 5-fold) in the 24 operated MP eyes than the 17 unoperated MP eyes (P < 0.001). Before surgery, EZD was present in 33% of operated MP eyes but none of the unoperated MP eyes (P < 0.02). The macula was thicker (514±85 μm vs. 257±59 μm; P < 0.001) with greater volume (3.22±0.56 μl vs. 2.14±0.22 μl; P < 0.001) in operated MP eyes than normal fellow eyes. Before surgery, MP eyes had VA = 0.53 logMAR (Snellen equivalent, 20/67) vs. controls = 0.21 (20/32); P < 0.001; CS was 8.61±5.36 %W vs. controls = 3.71±1.47 %W (P < 0.001); and distortions were 7.61±12.6 %DI vs. controls = 0.13±0.61 %DI (P < 0.001). EZD was associated with worse VA (P < 0.01) and CS (P < 0.03) before and after surgery. Each outcome measure improved progressively at 1, 3, 6, and 12 months after surgery, but only %DI and macular volume normalized.

CONCLUSIONS

These quantitative measures characterize the impact of MP on macular structure and function. All indices improved after surgery, but only distortions and macular volume normalized. Contrast sensitivity measurements and quantification of distortions can objectively assess visual dysfunction in MP and may be useful outcome measures of therapy.

Three-Dimensional Enhanced Imaging of Vitreoretinal Interface in Diabetic Retinopathy Using Swept-Source Optical Coherence Tomography

PURPOSE

To analyze the vitreoretinal interface in diabetic eyes using 3-dimensional wide-field volumes acquired using high-speed, long-wavelength swept-source optical coherence tomography (SSOCT).

DESIGN

Prospective cross-sectional study.

METHODS

Fifty-six diabetic patients (88 eyes) and 11 healthy nondiabetic controls (22 eyes) were recruited. Up to 8 SSOCT volumes were acquired for each eye. A registration algorithm removed motion artifacts and merged multiple SSOCT volumes to improve signal. Vitreous visualization was enhanced using vitreous windowing method.

RESULTS

Of 88 diabetic eyes, 20 eyes had no retinopathy, 21 eyes had nonproliferative diabetic retinopathy (NPDR) without macular edema, 20 eyes had proliferative diabetic retinopathy (PDR) without macular edema, and 27 eyes had diabetic macular edema (DME) with either NPDR or PDR. Thick posterior hyaloid relative to healthy nondiabetic controls was observed in 0 of 20 (0%) diabetic eyes without retinopathy, 4 of 21 (19%) eyes with NPDR, 11 of 20 (55%) eyes with PDR, and 11 of 27 (41%) eyes with DME (P = .0001). Vitreoschisis was observed in 6 of 22 (27%) healthy nondiabetic eyes, 9 of 20 (45%) diabetic eyes without retinopathy, 10 of 21 (48%) eyes with NPDR, 13 of 20 (65%) eyes with PDR, and 17 of 27 (63%) eyes with DME (P = .007). While no healthy nondiabetic controls and diabetic eyes without retinopathy had adhesions/pegs between detached posterior hyaloid and retina, 1 of 21 (4%), 11 of 20 (55%), and 11 of 27 (41%) eyes with NPDR, PDR, and DME, respectively, demonstrated this feature (P = .0001).

CONCLUSION

SSOCT with motion-correction and vitreous windowing provides wide-field 3-dimensional information of vitreoretinal interface in diabetic eyes. This may be useful in assessing progression of retinopathy, planning diabetic vitreous surgery, and predicting treatment outcomes.

VITREOMACULAR TRACTION AFTER DEXAMETHASONE INTRAVITREAL IMPLANT (OZURDEX) INJECTION: THE EFFECT OF ANOMALOUS POSTERIOR VITREOUS DETACHMENT

PURPOSE

To describe an unusual macular complication after dexamethasone intravitreal implant (Ozurdex) injection.

METHODS

Case history and macular optical coherence tomography findings are described. The report describes a patient with proliferative diabetic retinopathy and vitreoschisis who received Ozurdex treatment for diabetic macular edema.

RESULTS

After Ozurdex injection, visual acuity worsened because of newly formed vitreomacular traction that was demonstrated on optical coherence tomography imaging. A mechanism is proposed by which the medication might have contributed to this outcome.

CONCLUSION

In this patient with vitreoschisis, a thickened posterior hyaloid membrane and traction developed after Ozurdex injection. The authors recommend careful evaluation of the macula before injection, particularly in diabetic patients with vitreoschisis.

Cells at the vitreoretinal interface in small full-thickness macular holes

PURPOSE

To report on total number, distribution, and type of cells at the vitreomacular interface in small full-thickness macular holes.

METHODS

Internal limiting membrane specimens were removed from 20 consecutive patients with macular holes <250 μm at times when pharmacologic vitreolysis was not available. Specimens were flat mounted and investigated by phase contrast and interference microscopy and immunocytochemistry. Clinical data were documented including optical coherence tomography analysis using the caliper function. Thirteen antibodies were used for glial cells, hyalocytes, macrophages, retinal pigment epithelial cells, different types of collagen, alpha-smooth muscle actin, and proliferating cells.

RESULTS

There was a positive correlation between macular hole size and cell density at the internal limiting membrane (Spearman's Rho: r = 0.519, P = 0.019). Mostly, single glial cells were found on the internal limiting membrane. In five patients, cell clusters were present. There was a strong immunoreactivity for glial cell markers. Immunoreactivity of hyalocyte markers, alpha-smooth muscle actin, and Ki-67 was found in cell clusters but otherwise sparse.

CONCLUSION

Single cells of glial origin without signs of proliferation or contraction are present in eyes with small full-thickness macular holes. In some eyes, however, clusters of cells can be seen, capable of proliferation and exerting tangential traction. Our findings emphasize the need for better visualization of the vitreoretinal pathology by optical coherence tomography, especially to distinguish between single cells and cell clusters.

Current Trends about Inner Limiting Membrane Peeling in Surgery for Epiretinal Membranes

The inner limiting membrane (ILM) is the basement membrane of the Müller cells and can act as a scaffold for cellular proliferation in the pathophysiology of disorders affecting the vitreomacular interface. The atraumatic removal of the macular ILM has been proposed for treating various forms of tractional maculopathy in particular for macular pucker. In the last decade, the removal of ILM has become a routine practice in the surgery of the epiretinal membranes (ERMs), with good anatomical results. However many recent studies showed that ILM peeling is a procedure that can cause immediate traumatic effects and progressive modification on the underlying inner retinal layers. Moreover, it is unclear whether ILM peeling is helpful to improve vision after surgery for ERM. In this review, we describe the current understanding about ILM peeling and highlight the beneficial and adverse effects associated with this surgical procedure.

Retinal Changes Induced by Epiretinal Tangential Forces

Two kinds of forces are active in vitreoretinal traction diseases: tangential and anterior-posterior forces. However, tangential forces are less characterized and classified in literature compared to the anterior-posterior ones. Tangential epiretinal forces are mainly due to anomalous posterior vitreous detachment (PVD), vitreoschisis, vitreopapillary adhesion (VPA), and epiretinal membranes (ERMs). Anomalous PVD plays a key role in the formation of the tangential vectorial forces on the retinal surface as consequence of gel liquefaction (synchysis) without sufficient and fast vitreous dehiscence at the vitreoretinal interface. The anomalous and persistent adherence of the posterior hyaloid to the retina can lead to vitreomacular/vitreopapillary adhesion or to a formation of avascular fibrocellular tissue (ERM) resulting from the proliferation and transdifferentiation of hyalocytes resident in the cortical vitreous remnants after vitreoschisis. The right interpretation of the forces involved in the epiretinal tangential tractions helps in a better definition of diagnosis, progression, prognosis, and surgical outcomes of vitreomacular interfaces.

Tamponade or filling effect: changes of forces in myopic eyes

Myopia is the most common ocular abnormality. Its high and growing prevalence has contributed to a recent surge in surgical interest in the disorder, since retinal detachment in eyes with high myopia differs from that in emmetropic eyes or eyes with low myopia. The myopic eye, because of its specific anatomy, poses special challenges that need to be overcome to ensure the appropriate use of vitreous substitutes. However, intraocular tamponades have shown great potential for revolutionizing retinal detachment surgery and vitreomacular surgery in general in myopic eyes. We provide an updated review of the clinical use of vitreous substitutes in the myopic eye, paying particular attention to analyzing the ideal function of endotamponade agents and comparing the effects of these agents on the physical and biological properties of the eye.

Vitreopapillary traction in eyes with idiopathic epiretinal membrane: a spectral-domain optical coherence tomography study

PURPOSE

To investigate the prevalence of vitreopapillary traction (VPT) and its effect on peripapillary structure and visual function in eyes with idiopathic epiretinal membrane (ERM).

DESIGN

Observational, comparative study.

PARTICIPANTS

Patients with idiopathic ERM (n = 116 eyes) and controls with similar age (n = 62 eyes).

METHODS

Spectral domain optical coherence tomography (SD-OCT) axial optic disc scans were evaluated to identify VPT in eyes with idiopathic ERM. Based on VPT presence/absence, eyes were categorized as ERM with VPT (ERM+VPT, n = 52 eyes) or ERM without VPT (ERM-VPT, n = 64 eyes). Optic nerve head (ONH) parameters, average and sectoral retinal nerve fiber layer (RNFL) thickness, and central macular thickness (CMT) were compared between groups. Best-corrected visual acuity (BCVA) and visual field (VF) (automated Humphrey central 30-2 perimetry) mean deviation (MD) and pattern standard deviation (PSD) were compared between groups.

MAIN OUTCOME MEASURES

The ONH parameters, peripapillary RNFL thickness, BCVA, VF MD, and PSD.

RESULTS

Fifty-two of 116 eyes (44.8%) with idiopathic ERM had VPT. The ERM+VPT group had larger rim area, smaller average and vertical cup-to-disc ratios, and smaller cup volume than ERM-VPT and normal groups (all P < 0.001). Eyes with VPT had greater CMT than eyes without VPT (421.87±97.31 μm vs. 377.08±75.1 μm; P = 0.006). Average and temporal RNFL thickness was higher in ERM+VPT (98.64±9.33 μm and 93.90±23.42 μm) than in normal eyes (94.02±8.45 μm and 66.42±12.71 μm). No significant difference in BCVA was found between ERM-VPT and ERM+VPT eyes, but MD was lower in ERM+VPT than in ERM-VPT (-3.91±3.68 dB vs. -2.18±2.42 dB; P = 0.005). Additionally, PSD was greater in ERM+VPT. Multivariate logistic regression analysis revealed that age (odds ratio [OR], 1.190; P = 0.014) and increased CMT (OR, 1.013; P = 0.005) were associated with vision loss, whereas VPT presence was associated with VF defects (OR, 6.290; P = 0.024).

CONCLUSIONS

Vitreopapillary traction was observed in >40% of eyes with idiopathic ERM, as confirmed by SD-OCT imaging. Vitreopapillary traction with idiopathic ERM was associated with altered optic disc architecture, increased average and temporal RNFL thickness, and VF defects.

Oct-based interpretation of the vitreomacular interface and indications for pharmacologic vitreolysis

PURPOSE

To review the role of optical coherence tomography (OCT) in diagnosis and management of vitreomacular disease and the impact of OCT on potential uses of ocriplasmin, a new pharmacologic vitreolysis agent recently approved by the U.S. Food and Drug Administration for the treatment of symptomatic vitreomacular adhesion.

METHODS

Analysis of current literature regarding OCT in diagnosis and management of vitreomacular interface disease.

RESULTS

Posterior vitreous detachment is typically a nonpathologic age-related event. Anomalous posterior vitreous detachment emerges when the vitreous cortex fails to cleanly detach from the macula, optic nerve, or other adherent sites. Focal vitreomacular adhesion is a nonpathologic anatomical designation associated with perifoveal posterior vitreous detachment but normal retinal morphology on OCT. Vitreomacular traction is a pathologic consequence of persistent vitreous attachment with structural disturbance of the macular retina visible on OCT. Full-thickness macular holes are foveal defects continuous through all retinal layers to the retinal pigment epithelium. Vitreomacular traction and macular hole with focal vitreomacular adhesion are indications for pharmacologic vitreolysis.

CONCLUSION

Noninvasive high-resolution OCT imaging has transformed the understanding of vitreomacular interface disease. Careful evaluation of the vitreomacular interface with OCT has increased in importance with the introduction of ocriplasmin for vitreomacular adhesion associated with symptomatic anatomical retinal changes.

Comparison between subjective and objective internal limiting membrane peeling area during epiretinal membrane surgery

PURPOSE

To determine the reliability of surgeons in estimating internal limiting membrane peeling area during epiretinal membrane surgery and to evaluate their ability to remove a predetermined internal limiting membrane surface.

METHODS

One senior surgeon and two junior surgeons were asked to reach a target internal limiting membrane peeling surface (ILMPS) with an eccentricity of 1 optic disk diameter (centered on the fovea) in patients undergoing epiretinal membrane surgery. The ILMPS was measured on video recordings during epiretinal membrane surgery with no dye and then after brilliant blue G staining.

RESULTS

Thirty patients were included. Median (interquartile range) ILMPS was 9.3 mm(2) (5.7-16.3 mm(2)) and 7.4 mm(2) (3.7-16.4 mm) before and after brilliant blue G, respectively (P = 0.17). The ILMPS was significantly larger in eyes operated by the senior surgeon than in those operated by the junior surgeons (P = 0.01). The senior surgeon reached the target ILMPS more often than the junior surgeons: 87% versus 47%, respectively (P = 0.02).

CONCLUSION

Subjective estimation of the ILMPS with no dye was fair, but this area was larger for the surgeon with greater surgical expertise.

Spectral-domain optical coherence tomography evaluation of vitreoretinal adhesions in idiopathic epiretinal membranes

BACKGROUND

Vitreoretinal adhesions play a key role in the vector forces exerted on the vitreoretinal interface, leading to tractional retina deformation and macular hole formation. The aim of this study was to identify the presence of vitreopapillary and vitreofoveal adhesions in idiopathic epiretinal membranes (ERMs) with spectral-domain optical coherence tomography (SD-OCT) and to evaluate their influence on the vitreoretinal interface.

METHODS

Sixty-five eyes (65 patients) with idiopathic ERM and 64 healthy eyes (64 patients) underwent SD-OCT analysis. We studied vitreopapillary and vitreofoveal adhesion prevalence in eyes with idiopathic ERM using different SD-OCT patterns ("adherent" or "tractional"). We analyzed their influence on central foveal thickness (CFT), on retinal nerve fiber layer (RNFL) thickness, and on morphological modifications (foveal depression profile and inner/outer photoreceptor junction).

RESULTS

Vitreopapillary adhesion was present in 51.6 % of normal eyes and in 24.6 % of eyes with idiopathic ERM, while vitreofoveal adhesion was found in 14.1 % of normal eyes and in 15.4 % of eyes with ERM. Vitreopapillary adhesion prevalence was significantly higher in the tractional ERM subgroup (p = 0.01), than in the adherent ERM subgroup. Both adhesions had no influence on CFT, RNFL thickness, or inner segment/outer segment junction status.

CONCLUSIONS

Our study suggests that vitreoretinal adhesions may influence the pathogenesis and course of idiopathic ERM. The absence of vitreopapillary adhesion in the adherent type, and its presence in the tractional type, seems to play a key role in ERM characterization.

Surgical therapy versus observation for lamellar macular hole: a retrospective comparison study

BACKGROUND

The purpose of this study was to compare anatomic and visual changes in patients with lamellar macular hole undergoing pars plana vitrectomy with those in patients undergoing follow-up only.

METHODS

In this retrospective consecutive case series study, we evaluated two groups of eyes, comprising 19 eyes from 19 patients with lamellar macular hole who underwent pars plana vitrectomy with internal limiting membrane peeling and 21 eyes from 21 patients with lamellar macular hole who had follow-up only. Corrected distance visual acuity (CDVA, in logMAR) and optical coherence tomography findings, including measurements of maximum diameter of lamellar defect and foveal thickness, and whether the inner segment/outer segment band was intact or not were documented at initial and follow-up examinations.

RESULTS

At initial examination, mean CDVA was 0.54 logMAR in the study group and 0.51 logMAR in the control group, and 0.33 logMAR and 0.55 logMAR, respectively, on final examination. In the study group, postoperative optical coherence tomography images were found to be normalized in ten patients (52.6%), improved in six (31.5%), unchanged in two (10.5%), and to have progressed to full-thickness macular hole in one (5.2%) in the intervention group, while all patients in the control group were found to have deteriorated within the follow-up period between March 2004 and June 2010.

CONCLUSION

In patients with lamellar macular hole, combination treatment with pars plana vitrectomy and internal limiting membrane peeling appears to be effective, but further studies are required to establish new treatment modalities for patients who do not have a satisfactory outcome from treatment.

The International Vitreomacular Traction Study Group classification of vitreomacular adhesion, traction, and macular hole

OBJECTIVE

The International Vitreomacular Traction Study (IVTS) Group was convened to develop an optical coherence tomography (OCT)-based anatomic classification system for diseases of the vitreomacular interface (VMI).

DESIGN

The IVTS applied their clinical experience, after reviewing the relevant literature, to support the development of a strictly anatomic OCT-based classification system.

PARTICIPANTS

A panel of vitreoretinal disease experts was the foundation of the International Classification System.

METHODS

Before the meeting, panel participants were asked to review 11 articles and to complete 3 questionnaires. The articles were preselected based on searches for comprehensive reviews covering diseases of the VMI. Responses to questionnaires and the group's opinions on definitions specified in the literature were used to guide the discussion.

MAIN OUTCOME MEASURES

Optical coherence tomography-based anatomic definitions and classification of vitreomacular adhesion, vitreomacular traction (VMT), and macular hole.

RESULTS

Vitreomacular adhesion is defined as perifoveal vitreous separation with remaining vitreomacular attachment and unperturbed foveal morphologic features. It is an OCT finding that is almost always the result of normal vitreous aging, which may lead to pathologic conditions. Vitreomacular traction is characterized by anomalous posterior vitreous detachment accompanied by anatomic distortion of the fovea, which may include pseudocysts, macular schisis, cystoid macular edema, and subretinal fluid. Vitreomacular traction can be subclassified by the diameter of vitreous attachment to the macular surface as measured by OCT, with attachment of 1500 μm or less defined as focal and attachment of more than 1500 μm as broad. When associated with other macular disease, VMT is classified as concurrent. Full-thickness macular hole (FTMH) is defined as a foveal lesion with interruption of all retinal layers from the internal limiting membrane to the retinal pigment epithelium. Full-thickness macular hole is primary if caused by vitreous traction or secondary if directly the result of pathologic characteristics other than VMT. Full-thickness macular hole is subclassified by size of the hole as determined by OCT and the presence or absence of VMT.

CONCLUSIONS

This classification system will support systematic diagnosis and management by creating a clinically applicable system that is predictive of therapeutic outcomes and is useful for the execution and analysis of clinical studies.

Vitreopapillary and vitreomacular traction in proliferative Eales' disease

Vitreoretinal interface alterations leading to vitreopapillary and vitreomacular traction in a 29-year case of proliferative Eales' disease is described for the first time. On fundus examination, an ellipsoid area of vitreomacular traction was noted temporal to the optic disc. A triangular-shaped infolding of the retina was observed superior to the fovea. Epiretinal membrane was seen temporal to the disc involving the macula. Imaging by spectral domain optical coherence tomography in the papillomacular bundle region revealed retinoschisis at the level of the outer nuclear layer and confirmed the presence of retinal infolding and epiretinal membrane in the macular area. Three-dimensional imaging documented vitreoretinal interface alterations exquisitely.

Evaluation of a posterior vitreous detachment: a comparison of biomicroscopy, B-scan ultrasonography and optical coherence tomography to surgical findings with chromodissection

PURPOSE

To find the most reliable and efficient noninvasive technique to clinically detect a posterior vitreous detachment.

METHODS

In a prospective study of 30 eyes in 30 patients with macular pucker or macular hole formation, the posterior vitreous cortex was examined 1 day prior to a scheduled vitrectomy. Three independent investigators classified the posterior vitreous cortex of each eye as 'attached' or 'detached' via slit-lamp biomicroscopy (BM), 10-MHz B-scan ultrasonography (I³ Innovative Imaging Inc.), and optical coherence tomography [OCT III Stratus(®) (Carl Zeiss Meditec Inc.) and RTVue-100 OCT (Optovue Corp.)]. These preoperative findings were then compared during a triamcinolone acetonide-assisted vitrectomy 1 day later.

RESULTS

Triamcinolone acetonide-assisted vitrectomy showed in 60% a posterior vitreous detachment and in 40% an attached posterior vitreous cortex. Preoperatively conducted B-scan ultrasonography and BM revealed the highest, correct evaluation of the posterior vitreous status. The prediction of the OCT was confirmed intraoperatively in 12.5%. In all other cases, the evaluation by OCT was not possible or was inadequate.

CONCLUSION

The prognostic most reliable but investigator-dependent methods to clinically detect whether the posterior vitreous cortex is detached are B-scan ultrasonography and BM. The objective technique of the high-resolution, two-dimensional time-domain OCT allows only in a few cases a clear differentiation of preretinal structures.

Residual cellular proliferation on the internal limiting membrane in macular pucker surgery

PURPOSE

To provide pathology data on the completeness of epiretinal membrane (ERM) removal with and without internal limiting membrane (ILM) peeling.

METHODS

Twenty-two patients with idiopathic ERM formation underwent vitrectomy with ERM removal and subsequent staining of the vitreomacular interface with brilliant blue. If the ILM was still present after ERM removal, it was peeled off. Both ERM and ILM specimens were harvested in different containers and prepared for flat-mount phase-contrast and interference microscopy, immunocytochemistry, and transmission electron microscopy.

RESULTS

In 14 patients (64%), the ILM was still present at the macula after ERM removal. On average, 20% (range, 2-51%) of the total cell count was left behind at the ILM if the ERM was removed only. There were mainly glial cells on the ILM, and few hyalocytes. In nine eyes, the cells were forming cell clusters. In 8 patients (36%), both ERM and ILM were removed together. Electron microscopy showed cellular proliferation directly attached to the ILM in these eyes, whereas in the sequentially peeled group, there was collagen interposed between the ERM and the ILM. Surgical ERM removal resulted in splitting of the vitreous cortex in these eyes, leaving the ILM with residual cells behind.

CONCLUSION

Simple ERM removal results in sufficient separation of fibrocellular tissue in one third of cases, only. In 2 of 3 patients with idiopathic ERM, the vitreous cortex splits when the ERM is removed, leaving an average of 20% of the total cell count behind on the ILM. As these cells are capable of proliferation and causing ERM recurrence, staining of the ILM with subsequent removal seems beneficial in macular pucker surgery.

[The myopic vitreous. Why is its examination so difficult?]

The examination of a high myopic vitreous is difficult for several reasons, including optic phenomena and vitreous liquefaction. The diagnosis of a posterior vitreous detachment may be problematic and confused with the observation of a large lacuna posterior margin.

Vitreo-papillary adhesion as a prognostic factor in pseudo- and lamellar macular holes

PURPOSE

To determine the incidence of vitreopapillary adhesion (VPA) and to investigate its value as a prognostic factor in the surgical outcome of pseudo- (PMH) and lamellar macular holes (LMH).

METHODS

A total of 76 consecutive patients, diagnosed with PMH (41 eyes) or LMH (35 eyes) were included. Eyes with VPA were alternatively assigned to the surgical or control group. Surgery consisted of a 25G vitrectomy and internal limiting membrane peeling with blue dye staining. There were six visits: baseline, the day of surgery, and 1, 3, 6, and 9 post-operative months. Main outcome measures were the incidence of VPA and changes in the outer retinal layers and visual acuity.

RESULTS

VPA was found in 27% (11/41) of patients with PMH and 37% (13/35) with LMH (P=0.03). In presence of VPA, the best-corrected visual acuity (BCVA) improved in the surgery group from 32 ± 8 to 47 ± 8 letters, whereas the control group went from 34 ± 7 to 31 ± 8 letters. The difference in letters between the surgery and control groups was statistically significant for both distance (P=0.032) and near (P=0.04) vision. Intra-retinal cysts were significantly correlated with a poor functional prognosis (P=0.01). We found the presence of focal damage to the outer retinal layers in LMH and PMH.

CONCLUSION

VPA is more frequent in the presence of LMH vsPMH. It significantly influences the tangential forces at the vitreoretinal interface, exacerbating anatomical changes, and worsening the functional prognosis. Functional difference between the surgical and control groups was statistically significant for distant and near vision in presence of VPA.

Aging changes of vitreomacular interface

PURPOSE

The posterior precortical vitreous pocket (the pocket) is a premacular liquefied lacuna, the physiologic presence of which was reported in autopsy eyes. We describe the morphologic features of the pocket in normal individuals.

METHODS

We performed spectral-domain optical coherence tomography in 102 eyes of 51 normal subjects of various ages in a sitting position.

RESULTS

The pocket was identified as an optically lucent space anterior to the posterior fundus in 85 of 102 eyes (83.3%) in the age-group. The vitreous cortex was extremely thin at the central fovea, and it gradually thickened along with age in the perifoveal area. A shallow perifoveal posterior vitreous detachment developed in 16 of 32 eyes (50%) of subjects aged >51 years. The lamellar structure of the vitreous cortex was seen in 7 of the 32 eyes (22%) of subjects aged >51 years.

CONCLUSION

Spectral-domain optical coherence tomography confirmed the presence of the pocket in all ages. Thickened vitreous cortex and perifoveal posterior vitreous detachment were physiologic findings in older individuals. The lamellar structure of the vitreous cortex may be related to the vitreoschisis.

Vitreous substitutes: a comprehensive review

Vitreoretinal disorders constitute a significant portion of treatable ocular disease. Advances in vitreoretinal surgery have included the development and characterization of suitable substitutes for the vitreous. Air, balanced salt solutions, perfluorocarbons, expansile gases, and silicone oil serve integral roles in modern vitreoretinal surgery. Vitreous substitutes vary widely in their properties, serve different clinical functions, and present different shortcomings. Permanent vitreous replacement has been attempted with collagen, hyaluronic acid, hydroxypropylmethylcellulose, and natural hydrogel polymers. None, however, have proven to be clinically viable. A long-term vitreous substitute remains to be found, and recent research suggests promise in the area of synthetic polymers. Here we review the currently available vitreous substitutes, as well those in the experimental phase. We classify these compounds based on their functionality, composition, and properties. We also discuss the clinical use, advantages, and shortcomings of the various substitutes. In addition we define the ideal vitreous substitute and highlight the need for a permanent substitute with long-term viability and compatibility. Finally, we attempt to define the future role of biomaterials research and the various functions they may serve in the area of vitreous substitutes.