Occurrence Of Posterior Vitreous Detachment Research Articles

Epidemiology of Vitreomacular Interface Disorders

Vitreomacular interface disorders consist of a series of diseases including vitreomacular adhesion, vitreomacular traction, macular hole, and epiretinal membrane formation. They occur due to the failed progression of normal posterior vitreous detachment. Affected patients may present with metamorphopsia and varying degrees of visual loss depending on the severity of foveal disturbance and disease duration. The aim of this review is to define the epidemiological characteristics of these groups of disorders which show an increased incidence and prevalence with age in parallel with the occurrence of posterior vitreous detachment.

Deep Intronic Sequence Variants in COL2A1 Affect the Alternative Splicing Efficiency of Exon 2, and May Confer a Risk for Rhegmatogenous Retinal Detachment.

COL2A1 mutations causing haploinsufficiency of type II collagen cause type 1 Stickler syndrome that has a high risk of retinal detachment and failure of the vitreous to develop normally. Exon 2 of COL2A1 is alternatively spliced, expressed in the eye but not in mature cartilage and encodes a region that binds growth factors TGFβ1 and BMP-2. We investigated how both an apparently de novo variant and a polymorphism in intron 2 altered the efficiency of COL2A1 exon 2 splicing and how the latter may act as a predisposing risk factor for the occurrence of posterior vitreous detachment (PVD)-associated rhegmatogenous retinal detachment (RRD) in the general population. Using amplification of illegitimate transcripts and allele-specific minigenes expressed in cultured cells, we demonstrate variability in exon 2 inclusion not only between different control individuals, but also between different COL2A1 alleles. We identify transacting factors that bind to allele-specific RNA sequences, and investigate the effect of knockdown and overexpression of these factors on exon 2 splicing efficiency. Finally, using a specific cohort of patients with PVD-associated RRD and a control population, we demonstrate a significant difference in the frequency of the COL2A1 intronic variant rs1635532 between the two groups.

Shape Change of the Vitreous Chamber Influences Retinal Detachment and Reattachment Processes: Is Mechanical Stress during Eye Rotations a Factor?

We aim to understand how mechanical causation influences retinal detachment and reattachment processes. In particular, myopes suffer retinal detachment more frequently than emmetropes, and following a retinal detachment, scleral buckling promotes retinal reattachment. We test the hypothesis that stresses arising from saccadic eye rotations are involved in the processes, and that the alteration in the stress due to the change in the vitreous chamber geometry is sufficient to explain the phenomena. The vitreous chamber of the eye has an approximately spherical shape and it is filled with vitreous humor. We developed a mathematical model, treating the vitreous chamber in emmetropic and myopic eyes as a spheroid and in eyes subjected to scleral buckling as a sphere with a circumferential indentation. We assume that the eye performs prescribed small-amplitude, periodic, torsional rotations and we solve semi-analytically for the fluid pressure, velocity, and stress distributions. The shape of the vitreous chamber has a large effect on the retinal stress. The vitreous and the retina of a highly myopic eye continuously experience shear stresses significantly higher than those of an emmetropic eye. An eye fitted with a scleral buckle experiences large stress levels localized around the buckle. Our results provide a mechanical explanation for the more frequent occurrence of posterior vitreous detachment and retinal detachment in myopic eyes. To understand how the stress distribution in a buckled eye facilitates reattachment, an additional model of the details of the reattachment process should be coupled to this model.

Time course of posterior vitreous detachment in the second eye

Posterior vitreous detachment is the principal predisposing event for the development of retinal breaks and rhegmatogenous retinal detachments. Patients with unilateral posterior vitreous detachment are potentially at risk of developing the complications associated with posterior vitreous detachment in the fellow eye. Thus, to identify when posterior vitreous detachment develops in the fellow eye after it develops in the first eye is important for managing patients with unilateral posterior vitreous detachment. The main theme in the literature is research regarding the mechanism of the development of posterior vitreous detachment. Various pharmacologic vitreolysis agents can induce posterior vitreous detachment. Changes in the enzymatic activities in the vitreous and vitreoretinal interface tend to promote vitreous separation from the inner retinal surface with aging. Clinical studies have shown a significant increase in the occurrence of posterior vitreous detachment with aging, and the interval between the development of posterior vitreous detachment in the first eye and in the second eye is short. Posterior vitreous detachment is one of the most important age-related changes in human eyes, and age-related changes develop equally in both normal eyes; thus, posterior vitreous detachment may develop in the second eye within a few years of developing in the first eye.

Coma-like wavefront artifact induced by a posterior staphyloma and high refractive error

which is within the expected age range for RDs locally. We have shown that age is a risk factor for RD after laser refractive surgery. It is known that the vitreous undergoes syneresis between 40 and 60 years of age, and a syneretic vitreous is a prerequisite for the occurrence of posterior vitreous detachment and subsequent RD. It would have been interesting to establish the occurrence of posterior vitreous detachments after laser refractive surgery, but we were unable to do so with the limitations of a retrospective study. With longer axial lengths, the myopic eye has a greater tendency to lattice degeneration and PVD, predisposing to retinal tears and detachments. 7–9 The incidence of RD in myopes has been reported to range from 0.71% to 3.20%, increasing to 6.7% in high myopia. 10–13 The overall mean refractive errors at SNEC are 4.43 G 1.83 D for PRK and 6.37 G 2.80 D for LASIK. The patients who had RD after PRK and LASIK had mean preexisting SE of 8.53 G 2.71 D and 9.02 G 3.33 D, respectively. These results suggest that severity of myopia is a significant risk factor for RD after refractive surgery. Retinal detachments have been reported after laser refractive surgery, and the rates are low in general, ranging from 0.05% to 0.25%. 14–17 Our rate of 0.078% similarly falls within the reported range. It must be noted, however, that these rates depend on the duration of follow-up after the laser procedure and the severity of myopia that was treated. In addition, by analyzing the data of patients who returned to SNEC for management only, we were unable to determine the patients, if any, who received surgery for RD post laser refractive surgery at another hospital. Laser refractive surgery by PRK or LASIK is associated with low incidence of RD development. Retinal detachment is encounteredin the naturalhistory of myopiaand should be consideredan expected event, not entirely consequent to the laser procedure. However, the effect of vacuum suction and acoustic shockwaves of the laser may predispose the older high myopes to a higher risk for PVD and RD. Ophthalmologists who perform refractive surgery need to have a higher index of suspicion for RD when these patients are past 40 years of age and have a higher degree of myopia.

Posterior Vitreous Detachment: Clinical Correlations

Background: To evaluate the frequency of, and the factors which are primarily and secondarily associated with, posterior vitreous detachment (PVD), and to correlate the presence of PVD with various demographic and ophthalmic entities. Methods: The clinical prospective observational cohort study included 1,481 subjects (740 women, 741 men) with a mean age of 63.45 ± 14.97 years (mean ± SD; range, 10.3–94.9 years) and a mean spherical equivalent refractive error of +0.68 ± 2.13 dpt (range, –14.25 to +13.50 dpt). The presence of PVD was assessed by indirect and direct ophthalmoscopy, fundus biomicroscopy and by using a Hruby lens upon pharmacologically dilated pupil. Main outcome measures were frequency of PVD, association with age, refractive error, cataract surgery, diabetes mellitus, arterial hypertension, history of ocular trauma, vitreous hemorrhage, various retinal disorders, nonarteritic anterior ischemic optic neuropathy (AION) and open-angle glaucoma. Results: The occurrence of PVD was significantly correlated with increasing age (p < 0.001), myopic refractive error (p < 0.001), female gender (p < 0.001), and surgical aphakia (p < 0.001). PVD occurred significantly more often bilaterally than unilaterally (p < 0.001). Patients with unilateral PVD were significantly (p < 0.001) younger than the patients with bilateral PVD. PVD was seen significantly (p = 0.038) less frequently in AION than in the remaining study population. The frequency of PVD was lower in eyes with than without diabetic retinopathy (p = 0.095), optic disc neovascularization (p = 0.07) and retinal neovascularization (p = 0.09). There was no significant association between the presence of PVD and macular hole, macular edema, retinal vascular occlusive disorders, age-related macular degeneration and open-angle glaucoma. Conclusions: These data of a large prospective study of PVD confirm some of the findings of previous smaller and retrospective studies. They also provide new information which may be helpful for the understanding of the pathophysiology of PVD and the role of PVD in the pathogenesis of various retinal and optic disc lesions.

Histopathological Examination of Tissues Removed from the Retinal Surface during Vitrectomy in Idiopathic Macular Holes

We examined electron microscopically the tissues removed from the retinal surface in cases with idiopathic macular holes. We performed vitrectomy for idiopathic macular holes in 43 eyes from June 1994 to December 1998 at Fukuoka University Chikushi Hospital. The removed tissues were evaluated with transmission electron microscope in only 8 of the 43 eyes. All cases underwent 3 port vitrectomy. After occurrence of posterior vitreous detachment, epiretinal tissues were removed around the macular hole using a micro-hook needle. All tissues were transparent under an operating microscope, and they curled naturally. Histopathological examination showed that the removed tissues were from 2 to 6.5 microns thick. All tissues were composed mainly of extracellular matrix. There were type 2 collagen fibers in 6 eyes and basement membrane-like structures in 2 eyes. There were few cell components. All cases had the macular hole closed by the first surgery. Four eyes had improved visual acuities of more than 2 lines. The remaining 4 eyes had the same visual acuity as before the operation. Residual vitreous on the retinal surface was the main component of the transparent tissues removed from the retinal surface during vitrectomy.

Factors Related to Intraoperative Retinal Breaks in Macular Hole Surgery

To evaluate the factors of intraoperative retinal breaks in macular hole surgery. This study included 558 eyes of 506 patients who underwent idiopathic macular hole surgery by one surgeon. Multiple regression was performed using the variables of gender, age, affected eye, lens status, stage, duration of symptoms, hole size, axial length, and lattice degeneration. The rate of retinal breaks was higher in stage 3 (16.0%) than in stage 4 (8.2%) (p = 0.014). In eyes with lattice degeneration intraoperative retinal breaks occurred in about 40% of the cases. Major factors were as follows: lattice degeneration (r = 0.24, p < 0.0001) in all eyes, stage (r = 0.090, p = 0.048) in eyes without lattice degeneration, and gender (r = -0.18, p = 0.035) in eyes of stage 4 without lattice degeneration. The factors of intraoperative retinal breaks in macular hole surgery were lattice degeneration in all eyes and stage 3 in eyes without lattice degeneration. The high incidence of intraoperative retinal breaks in stage 3 was mainly due to the occurrence of posterior vitreous detachment. Male gender was a significant factor associated with intraoperative retinal breaks.

What happens to untreated asymptomatic retinal breaks, and are they affected by posterior vitreous detachment?

Objective The purpose of the study was to ascertain the natural consequences of asymptomatic retinal breaks and to learn what effects, if any, the occurrence of posterior vitreous detachment (PVD) has on such breaks. Design This was a cohort study of consecutive asymptomatic phakic patients, all of whom had asymptomatic retinal breaks, observed without treatment over periods of 1 to 33 years (average, 11 years). Participants There were 196 patients with 235 involved eyes. Intervention Periodic clinical examinations, including binocular indirect ophthalmoscopy with scleral indentation on all eyes and posterior vitreous examination on 50 eyes, were performed. Results In the total study period, one small peripheral retinal detachment developed, without symptoms, from a previous subclinical detachment over a period of 14 years. Nineteen eyes (8%) originally had or developed 22 areas of subclinical detachment, 2 of which were treated because of moderate extension, even though remaining subclinical and without symptoms. Ten eyes encountered acute PVDs, which caused symptomatic retinal tears in three eyes, one of which also had a clinical retinal detachment. Of the 50 asymptomatic eyes examined with Goldmann lens and slit lamp, 12 (24%) were found to have an existing PVD, which had not led to any complication of the previous retinal breaks in any eye. Conclusions Asymptomatic retinal breaks discovered in phakic primary eyes do not show any significant tendency toward clinical retinal detachment, with the exception of a few of those cases that progress to subclinical retinal detachment. It is only some of these, comprising 1% to 2% of the total group, that may justify treatment. Posterior vitreous detachment coexists safely with asymptomatic retinal breaks in phakic primary eyes and shows no tendency to provoke complications to pre-existing breaks at the time of its occurrence.

VITRECTOMY FOR PROLIFERATIVE DIABETIC RETINOPATHY WITH ASTEROID HYALOSIS

Purpose: To characterize the clinical features of proliferative diabetic retinopathy (PDR) with asteroid hyalosis treated by pars plana vitrectomy. Methods: Vitrectomy was performed in 26 eyes with PDR accompanied by asteroid hyalosis (7 eyes with vitreous hemorrhage, 6 eyes with tractional retinal detachment with vitreous hemorrhage, and 13 eyes with tractional retinal detachment without vitreous hemorrhage). We observed the occurrence of posterior vitreous detachment intraoperatively and evaluated the clinical characteristics retrospectively. Results: In 24 eyes, posterior vitreous detachment was slight, necessitating artificial detachment. Of the 26 eyes, 20 experienced iatrogenic retinal breaks and 6 (23%) experienced postoperative retinal detachment due to iatrogenic breaks. Three cases worsened to anterior proliferative vitreoretinopathy and retinal reattachment could not be achieved. Conclusions: In vitrectomy for PDR with asteroid hyalosis, and in cases of simple vitreous hemorrhage, surgery should be performed with full understanding of the anatomic characteristics. Notably, if posterior vitreous detachment is not present, the occurrence of iatrogenic retinal breaks is more likely.

Role of Posterior Vitreous Detachment in Idiopathic Macular Holes

Akiba, J.; Quiroz, M. A.; Trempe, C. L.Editor(s): Blumenkranz, Mark S. Author Information

Role of Posterior Vitreous Detachment in Idiopathic Macular Holes

The role of posterior vitreous detachment in the formation of idiopathic macular hole was evaluated in 310 eyes. The eyes were classified according to the stage of the initial macular pathology: group 1, macular cyst; group 2, early macular hole; and group 3, fully developed macular hole. The initial prevalence of posterior vitreous detachment was 0% (none of 15 eyes) in group 1, 6% (three of 50 eyes) in group 2, and 27% (67 of 245 eyes) in group 3. During the study, all 15 eyes in group 1 and all 43 eyes in group 2 for which data were obtained progressed to fully developed macular holes without the occurrence of posterior vitreous detachment. The findings strongly suggested that most idiopathic macular holes develop in the absence of posterior vitreous detachment and that the pathogenesis of the holes may be independent of the occurrence of posterior vitreous detachment.