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Spontaneous posterior vitreous detachment (PVD) is a common age-related condition in which prevalence tends to increase with age. Acute PVD can cause the onset of symptoms that include visual disturbances, myodesopsia and photopsia. The goal of this short review was to provide a quick glance at the important factors related to PVD based on current literature in this field, which includes incidence, symptoms, diagnosis, risk factors, and education for patients with acute symptoms, and treatments. The take home message is that an ophthalmic examination at the onset of symptoms is of utmost importance, considering that irreversible sight-threatening complications can be prevented if diagnosed and treated promptly.

ObjectiveTo determine whether handheld widefield optical coherence tomography (OCT) can be used to document retinopathy of prematurity (ROP) stage while using scleral depression to improve peripheral views.DesignProspective observational studyParticipantsConsecutive neonates admitted to the neonatal intensive care unit (NICU) in a single academic medical center who also met criteria for ROP screening and consented for research imaging.MethodsScleral depression was combined with widefield OCT using an investigational 400-kHz, 55-degree field of view handheld OCT during ROP screening from October 28, 2020 to March 03, 2021.Main Outcome MeasuresAcquisition of en face and B-scan imaging of the peripheral retina to objectively assess early vitreoretinal pathology, including the demarcation between vascularized and anterior avascular retina, the presence of early ridge formation, and small neovascular tufts.ResultsVarious stages of ROP were detected using a rapid acquisition OCT system. In one neonate, serial OCT imaging over a five-week period demonstrated accumulation of neovascular tufts with progression to stage 3 ROP with extraretinal fibrovascular proliferation along the ridge. Videography of this technique is included in this report for instructional purposes.ConclusionsSerial examinations using widefield OCT and scleral depression may improve detection and documentation of ROP disease progression. Earlier detection of ROP-related proliferation may prevent vitreoretinal traction, retinal detachment, and blindness.

The purpose of this study was to determine the relationship between a posterior vitreous detachment (PVD) and retinoschisis (RS) in 73 highly myopic (HM) young patients age 16.4 ± 6.9 years and 24 non-HM children age 8.4 ± 1.5 years. The presence of the paravascular retinal abnormalities was determined in the images obtained by a ultra-widefield OCT (UWF OCT) instrument with an image field of 23 × 20 mm. The results showed that a partial PVD was detected in 15 (21%) of the HM patients, and the number increased significantly with increasing age (P = 0.02). PVDs of any type were not found in the non-HM eyes. The number of microvascular folds also increased with age in the HM patients (P = 0.03). Medium-reflective columnar tissues were present between the detached vitreous and inner retinal surface in 4 (5%) eyes of the HM patients. Myopic RS was found in 3 (4%) HM patients in the paravascular area but not in the macular area. These results suggest that early partial PVD may play a role in pathological and proliferative vitreous changes of HM eyes. An intense vitreoretinal traction with bridging tissues may cause the various paravascular retinal abnormalities. In HM eyes, paravascular RS is already present at an early age which may progress to macular RS with aging.

A macular hole is a full-thickness defect in the foveal neuroretinal tissue that can cause significant vision loss. While the majority of macular holes are “idiopathic” and age-related in nature, occurring as a result of a slow, degenerative process of progressive vitreoretinal traction, almost all macular holes encountered in the pediatric population are the result of direct ocular trauma. Owing to its disparate pathophysiology, the clinical course and prognosis of the pediatric traumatic macular hole is less predictable than that of idiopathic senile macular hole. Other traumatic ocular comorbidities may affect management and/or visual prognosis. Spontaneous closure may occur, and a period of observation is often undertaken, although considerations for deprivational amblyopia may prompt earlier intervention in younger patients. While surgical management is similar to that for idiopathic senile macular holes, the pediatric population poses unique surgical challenges including the adherent posterior hyaloid and limitations in the ability to position face-down postoperatively. This chapter provides an overview of pediatric traumatic macular holes, with attention to the key differences in epidemiology, anatomy, pathophysiology, diagnosis, and management in children, as compared to adults.

This is a case of toxoplasmosis retinochoroiditis which has resulted in the formation of vitreomacular traction upon resolution which is rarely associated with ocular toxoplasmosis. A 39-year-old male came with an active toxoplasmosis retinochoroiditis. Best-corrected visual acuity, full ophthalmic slitlamp examination, colour fundus photography, spectral domain optical coherence tomography (SD-OCT), and fluorescein angiography were performed. Presumed ocular toxoplasmosis diagnosis was supported by serological tests. The patient was treated medically for 45 days and on his follow up he developed macular traction which was shown in SD-OCT with a good visual acuity. Vitreoretinal traction is a rare complication of ocular toxoplasmosis and ranges from mild to severe traction which might require surgery. We suggest a close follow up for patients with toxoplasmosis retinochoroiditis and early recognition could avoid exposing patients to surgery. Keywords: Ocular toxoplasmosis, Toxoplasma retinochoroiditis, Vitreomacular traction

Purpose To determine the incidence of worsening vitreoretinal traction after laser treatment for familial exudative vitreoretinopathy (FEVR) and to determine whether any baseline clinical features are associated with worsening. Design Retrospective cohort comparison study in a university tertiary referral center. Methods: All patients 0-21 years of age treated with laser from January 1, 2001, to June 1, 2018, were studied. Worsening traction after treatment was defined as the occurrence within 6 months of worsening or development of tractional retinal detachment, folds, dragging, breaks, rhegmatogenous detachment, or worsening tractional membranes. Comparisons of baseline features between groups with and without worsening were performed to determine features associated with higher risk. Results A total of 46 eyes from 28 patients met inclusion criteria. Of the 46 eyes, 6 (13%) had worsening after treatment. There were no significant differences in age or other baseline demographics between the cohorts with and those without worsening traction. The presence of proliferative tissue in contact with the lens was found in 2 of 6 patients with worsening compared to 1 of 40 (3%) without worsening (P = .04). Mean follow-up was 57.8 months (range, 6.6-134 months). At the 6-month follow-up, median logMAR visual acuity in the cohorts with and without worsening was 1.7 (Snellen 20/1002; n = 5) and 0.24 (Snellen 20/35; n = 16), respectively. Conclusions Laser treatment resulted in worsening traction in a substantial proportion of eyes with FEVR. Children with proliferative tissue in contact with the lens may be at higher risk of worsening after laser. Potential measures to reduce risk will require further study to establish efficacy.

To investigate the structural and functional characteristics and change of the retinal nerve fiber layer cleavages (RNFLCs) in glaucoma patients and suspects in long-term follow-up. This is a retrospective longitudinal study. Within 43 eyes of 30 subjects, 62 RNFLC locations were detected on color fundus photography. Basic ophthalmic examinations, color fundus photography, optical coherence tomography (OCT), and visual field (VF) test were performed in 6-month intervals. Clinical characteristics and the structural and functional changes of the cleaved areas were analyzed. RNFLC and localized vitreoretinal traction occurred most commonly along the superotemporal retinal vessel arcade. Nine locations had corresponding defects on OCT deviation map, while 31 locations were associated with defects on OCT deviation map. Three locations had corresponding VF defects. More of the non-highly myopic eyes had lamellar hole than the highly myopes (p = 0.038). The RNFLC lesions in glaucomatous eyes were more frequently associated with OCT defects on deviation map (p = 0.021). There was no difference in the presence of lamellar hole or the number of RNFLCs between the glaucomatous and non-glaucomatous eyes. During a 66.8 ± 37.8-month follow-up, there was no structural or functional progression of the RNFLCs as determined by color fundus photography, VF test, and GPA of OCT interpreted by three ophthalmologists. There was no statistically significant change of RNFLC area (p = 0.268). RNFLC did not show detectable functional or structural change in early glaucoma patients and suspects after long-term follow-up.

Vitreoretinal interface pathologies, such as vitreomacular traction syndrome, epiretinal membranes and macular holes are sight-threatening conditions and one of the important causes of vision defects and vision loss. To this date, vigilance with observation of how the vitreomacular traction resolves, or vitreoretinal surgery in more severe cases, were the only treatment options. Recent rapid progress in ophthalmology, especially in diagnostic and visualization techniques, provided better insight into the mechanisms taking place on the vitreoretinal surface, which enabled a more accurate selection of treatment options. Development of ophthalmic pharmacological procedures, such as treatment of vitreomacular traction syndrome with ocriplasmin, constitutes an innovative breakthrough in ophthalmology. The enzyme is a genetically engineered form of human plasmin, a component of blood coagulation cascade that has been envisioned for human therapy since 1950s. It has never been used for vitreolysis in ophthalmology before. The aim of this review is to analyze and compare therapeutic options for symptomatic vitreomacular adhesion and vitreoretinal traction, with particular emphasis on microplasmin. We reviewed the results of recent studies comparing ocriplasmin to other widespread treatment options, such as pars plana vitrectomy.

Vitreoretinal surgery mainly consists of scleral surgery (external-route) and pars plana vitrectomy. The former aims to relieve vitreoretinal traction or close retinal breaks through external scleral indentation buckling with silicone sponge, while the latter is used for vitreous opacities clearance, vitreoretinal traction relief, and retinal structure restoration by removing part or the whole vitreous through three approaches via pars plana.

Purpose: Vitrectomy is usually only indicated for familial exudative vitreoretinopathy (FEVR) cases with progressive retinal folds or macular dragging. In this report, we present our experience reversing the progression of macular dragging by performing early eye vitrectomies in a 1-month-old male baby with FEVR. Observations: A 7-day-old, full-term male baby was examined by a pediatric ophthalmologist. His sister had a laser ablation treatment after being diagnosed with FEVR. The ophthalmologist found the baby had avascular retinas, fibrovascular membranes, and vitreous hemorrhages in both eyes, and performed retinal photocoagulations the next day. Although the retinal folds had not yet formed, the arcade vessels began to linearize after the procedure, strongly suggesting disease progression. Therefore, we performed lens-sparing vitrectomies in both eyes on the twenty-ninth day of life. After surgery, the macular dragging reversed, as evidenced by vascular arcade angle measurements. Three years after the surgery, the boy's visual acuity was 0.4 in both eyes. Conclusions and Importance: In this case, we believe the good postoperative outcomes were due to early vitrectomies before the vitreoretinal traction became severe. In addition, the retinal photocoagulation performed on the eighth day of life may have reduced disease activity, at least partially. This case highlights the importance of prompt diagnosis and appropriate treatment of FEVR. Keywords: Familial exudative vitreoretinopathy, Vitrectomy, Early treatment, Laser photocoagulation, Retinal fold

Traumatic macular hole occurs most often in young men and can present after various types of injuries. Traumatic macular holes result from anteroposterior and tangential vitreoretinal traction and may exhibit concurrent additional pathologies such as Berlin’s edema and subretinal fluid. Optical coherence tomography can play an essential role in patient management both at presentation and during follow-up. Initial management consists of observation, but macular hole repair can be performed if spontaneous resolution does not occur. Upon macular hole closure, vision may improve, on average, by two lines or more but may be limited by associated macular pathology.

Purpose Abusive head trauma (AHT) is the leading cause of infant death and long-term morbidity from injury. The ocular consequences of AHT are controversial, and the pathophysiology of retinal research findings is still not clearly understood. It has been postulated that vitreoretinal traction plays a major role in the retinal findings. A computer simulation model was developed to evaluate the vitreoretinal traction and determine whether the distribution of forces in different layers and locations of the retina can explain the patterns of retinal hemorrhage (RH) seen in AHT. Design Computer simulation model study. Methods A computer simulation model of the pediatric eye was developed to evaluate preretinal, intraretinal, and subretinal stresses during repetitive shaking. This model was also used to examine the forces applied to various segments along blood vessels. Results Calculated stress values from the computer simulation ranged from 3-16 kPa at the vitreoretinal interface through a cycle of shaking. Maximal stress was observed at the periphery of the retina, corresponding to areas of multiple vessel bifurcations, followed by the posterior pole of the retina. Stress values were similar throughout all 3 layers of the retina (preretinal, intraretinal, and subretinal layers). Conclusions Ocular manifestations from AHT revealed unique retinal characteristics. The model predicted stress patterns consistent with the diffuse retinal hemorrhages (RH) typically found in the posterior pole and around the peripheral retina in AHT. This computer model demonstrated that similar stress forces were produced in different layers of the retina, consistent with the finding that retinal hemorrhages are often found in multiple layers of the retina. These data can help explain the RH patterns commonly found in AHT.

To demonstrate vitreoretinal traction as a mechanism for perimacular folds in abusive head trauma.We performed gross and histopathologic examination of eyes of children with suspected abusive head trauma and identified those with typical perimacular folds. Information was collected regarding the incident that led to the child's death and systemic manifestations noted at autopsy. Eyes were prepared in a fashion that allowed for demonstration of the vitreoretinal interface.Ten eyes of five patients (2-13 months) were examined. All patients had systemic manifestations of abusive trauma including intracranial injury. All cases provided evidence of vitreoretinal traction producing perimacular folds. Condensed vitreous was seen attached to the apices of the retinal folds, and the detached internal limiting membrane comprising the inner surfaces of the schisis cavity. Four cases showed severe bilateral multilayered symmetric retinal hemorrhages extending to the ora serrata. All cases showed optic nerve sheath subdural hemorrhage and subarachnoid hemorrhage. Orbital hemorrhage was unilateral in two cases and bilateral in three cases. Four cases showed orbital fat hemorrhage. One case showed extraocular muscle sheath and cranial nerve sheath hemorrhage. Two cases showed juxtapapillary intrascleral hemorrhage.Vitreoretinal traction is the likely mechanism of perimacular folds in abusive head trauma.

Purpose: To evaluate the feasibility and outcomes of the sole use of 23g pars plana vitrectomy in cases with diabetic vitreous hemorrhage with vitreoretinal traction. Methods: Prospective interventional case series involving patients between January 2013 and January 2018. All eyes underwent 23g pars plana vitrectomy with internal tamponade. Intraoperative parameters including ancillary instruments, the methods used for hemostasis and complications were all recorded. Postoperative parameters including anatomic success rate, functional success, and postoperative complications were recorded and analyzed. Patients were followed up for at least 12 months. Results: A total of 68 eyes of 66 patients were included. Intraoperative ancillary instruments were required in 5 (7.4%) eyes. None of the cases required the use of chandelier illumination, endodiathermy, or scissors. Mean best-corrected visual acuity improved significantly from LogMAR 1.67 ± 0.63 preoperative to 1.22 ± 0.38 at 1-year follow-up (P = 0.005). Functional success was achieved in 37 (54.4%) eyes at 1-year follow-up. Iatrogenic breaks occurred in 3 (4.4%) eyes, vitreous hemorrhage in 4 (5.9%) eyes, and epiretinal membranes in 3 (4.4%) eyes. Repeated vitrectomy was done in 3 (4.4%) eyes. Conclusion: The 23g vitrectomy probe proved to be a safe, effective, and beneficial single tool that could accomplish the diabetic vitrectomy mission exclusively with minimal aid from other instruments in cases with vitreous hemorrhage associated with vitreoretinal traction.

Purpose: To compare the efficacy and safety of intravitreal ranibizumab (IVR) in monotherapy or associated with panretinal photocoagulation (PRP) versus conventional PRP, for high-risk proliferative diabetic retinopathy (PDR) without vitreoretinal traction. Procedures: Multicenter randomized trial, with 3 treatment arms: PRP versus IVR alone and PRP + IVR combined treatment. Follow-up was performed at months 3, 6 and 12. Results: Thirty-five subjects were randomized and 32 used for analysis. Complete regression of neovessels elsewhere occurred in 100% (PRP + IVR), 75% (IVR) and 69.2% (PRP) and for neovessels of the disk in 44.4% (PRP + IVR), 37.5% (IVR) and 30.8% (PRP). During the 1-year duration of treatment, there was no need for laser rescue treatment in IVR-treated eyes. Conclusions: This trial suggests that the use of IVR is safe and may have a beneficial effect in the treatment of eyes with high-risk PDR. Message: Ranibizumab appears to have a place in the treatment of PDR.

Purpose To describe the use of multimodal imaging in defining the anatomical features of combined harmatoma of the retina and retinal pigment epithelium (CHRRPE) and assess its role in the diagnosis and management of CHRRPE. Methods Retrospective case series of three patients with unilateral, juxta-papillary CHRRPE, who underwent Spectralis Enhanced Depth Imaging Optical Coherence Tomography (EDI-OCT), MultiColor (MC) and autofluorescence (AF) in addition to a complete ophthalmic examination. Results EDI-OCT demonstrated thickening and disorganisation of retinal architecture, with intraretinal cysts disrupting the retinal layers and a loss of photoreceptors. An overlying epiretinal membrane was shown to be causing ‘mini-peaks’ of the inner retinal surface in all cases and vitreoretinal traction in two cases. Details of the retinal pigment epithelium (RPE) were revealed, including RPE thickening and sectoral atrophy. MC revealed areas of red-shifting, demonstrating partial pigmentation. On green reflectance (GR) the degree of inner retinal distortion and extent of macular involvement could be visualised. Near infra-red (NIRR) reflectance displayed the lesions as areas of hyporeflectance and allowed delineation of the tumour borders. On AF, the lesions were represented by areas of hypo-autofluorescence that obscured the normal blood vessel hypo-autofluorescence. Conclusions In this case series, multimodal imaging enabled the anatomical characteristics of CHRRPE to be defined in greater detail. NIRR enabled better visualisation of tumour boundaries and the extent of macular involvement, which may be useful in assessing the impact on visual function. GR better defined the degree of inner retinal distortion, which may be useful in surgical management decisions. We believe that multimodal imaging is a valuable adjunct in correctly diagnosing and managing CHRRPE.

Purpose: Ocriplasmin injection may close some small-to-medium macular holes associated with vitreoretinal traction. If the treatment fails, does vitrectomy and gas injection yield the same results as primary surgery? Material and Methods: We report a retrospective case series study of 3 eyes of 3 consecutive patients operated on a few months after initial intravitreal injection of ocriplasmin and enlargement of the macular hole. The minimal follow-up period after surgery was 18 months. Results: Surgery was uneventful in all cases. Vitrectomy, internal limiting membrane peeling, and gas injection allowed closing of the 3 macular holes with a progressive improvement in visual acuity over time. Before ocriplasmin injection, visual acuity ranged from 20/60 to 20/32, after failed ocriplasmin injection from 20/80 to 20/40, and at the final follow-up after 18 months from 20/32 to 20/25. Conclusion: Vitrectomy with internal limiting membrane peeling leads to closure of macular holes even in cases of prior failure to close them by ocriplasmin injection.

We aimed to elucidate the mechanism of the retinal hemorrhage (RH) accompanied by shaken baby syndrome or abusive head trauma (SBS/AHT) by analyses using a computational model. We focused on a hypothesis that the vitreoretinal traction due to acceleration and deceleration caused by abusive shaking leads to retinal hemorrhage. A finite element (FE) mechanical model with simple spherical geometry was constructed. When the FE mechanical model was virtually shaken, the intensity of the stress applied to the retinal plane agreed well with the results from an analysis using a physical model made of agar gel. Impacts due to falling events induced more intensive tensile stresses, but with shorter duration, than the shake did. By applying a mathematical theory on tackiness, we propose a hypothesis that the time integration of the stress, in the unit of Pa·s, would be a good predictor of the RH accompanied by SBS/AHT. A single cycle of abusive shake amounted to 101Pa·s of time integration of inflicted stress, while a single impact event amounted to 36Pa·s. This would explain the paradoxical observation that shaking induces RH while RH due to impact events is only seen in a major event such as a fatal motor vehicle accident.

Purpose Inflammation due to retinal neuroepithelial necrotic granulomas of toxoplasmosis can extend to neighbor areas and may develop focal adhesions of the posterior hyaloid, to the surface vessels, and the margins or adjoining areas of retinochoroiditis plaques. These adhesions may develop vitreoretinal traction and retinal tears. Vitreoretinal traction may be macular (VMT) or extramacular depending on the location of the toxoplasmic plaques. Vitreomacular traction may follow anomalous posterior vitreous detachment. We report 7 cases of vitreoretinal traction (macular or peripheral) and the development of 4 lamellar macular holes in cicatricial toxoplasmic retinochoroiditis. Methods This is a retrospective and observational study by revision of clinical records in a retinologist office, using diagnostic techniques, especially optical coherence tomography (OCT), current management, and an extended follow-up. The OCT observations on toxoplasmic extramacular plaques are more difficult. Results Seven cases in 5 patients, 2 of them bilateral, 3 male (66.6%) and 2 female, median age 46 years, were included. Anteroposterior VMT was found in 6 cases and another case was superotemporal midperipheral; 4 developed lamellar macular holes and 3 chronic macular epiretinal membranes. Best-corrected visual acuity was equal to or better than 20/30 in 3 cases, between 20/50 and 20/80 in 2 cases, and 20/160 to 20/200 in 2 cases. One small lamellar macular hole closed spontaneously during follow-up. Conclusions Inflammatory retinal granulomas of toxoplasmosis in cicatricial stages may present macular or peripheral focal vitreoretinal adhesions that can eventually lead to VMT and subsequent lamellar macular holes or peripheral retinal tears.

Pseudophakic cystoid macular oedema is still a relevant clinical disease entity although major progress in modern cataract surgery has been made within the last decades. The relevance is attributed to the large number of cases that are performed each year. Even after uneventful surgery, a pseudophakic cystoid macular oedema can develop and may lead to severe and lasting visual impairments. In respect to the pathophysiology, four consecutive steps have to be considered: (i) surgical procedure-related induction and release of various inflammation mediators into the anterior chamber; (ii) removal of the physiological lens barrier between the anterior and posterior segments of the eye, leading consecutively to an increase in diffusion rate in either direction; (iii) local action of the inflammation mediators towards the macular area; and (iv) increased vitreoretinal traction due to the anteriorly oriented drive of the vitreous. To prevent the development of a pseudophakic cystoid macular oedema, systemic and ocular pathologies should be treated consequently prior to surgery. Furthermore, an individual risk profile of each patient needs to be evaluated to define the best pre- and postsurgical medical treatment. A less traumatic surgical approach can help to prevent macular oedema development additionally. The diagnosis is made by performing biomicroscopy, fluorescence angiography and optical coherence tomography as well as by evaluating the patients' major complaints. Standard operation procedures or recommended guidelines by the specialised eye associations to prevent and treat pseudophakic cystoid macular oedema are not available up to date. A synopsis of recommendations in the literature suggests a step-wise treatment regimen, including topical medical treatment on the one hand and a surgical approach on the other hand as well as a combination of both, if needed. Topical medical treatment options include the use of non-steroidal, corticosteroid and/or carbonic anhydrase inhibitor eye drops. Surgical interventions include pars plana vitrectomy.

Purpose: To describe an association between extrafoveal vitreoretinal traction and intractable chronic pseudophakic cystoid macular edema (CME) by the use of optical coherence tomography (OCT). Methods: In a retrospective case series study, charts and OCT findings of patients who had postoperative recalcitrant pseudophakic CME for at least 6 months and vitreoretinal traction membranes were analyzed. Excluded were eyes that either had another vitreoretinopathy that could affect the analysis or had undergone an intravitreal intervention. Results: Three eyes (three patients) with macular edema following uneventful cataract surgery were detected to be associated with multifocal extrafoveal vitreoretinal traction sites in each. Retinal edema that was underlying each of the traction sites in all eyes was in continuum in at least one site per eye with the central macular edema, thus manifesting as diffuse macular edema. Conclusion: Chronic pseudophakic macular edema may be related to extrafoveal vitreoretinal traction.

The periphery of the vitrectomised eye is the site of retinal breaks in 1 to 15% of cases. These breaks must be looked for and treated to avoid retinal detachment. They are more frequent in the presence of fragile lesions in high myopia, or vitreoretinal traction. They can be related to vitreous incarceration in a sclerotomy site or with the movements of the vitrectomy probe. Traction is proportional to aspiration rate, and inversely proportional to the distance between the cutter and the vitreous base. Twenty-three- or 25-gauge transconjunctival vitrectomy seems to decrease the risk of vitreous incarceration and peripheral retinal tear.

Shuichiro Hirahara, Yoshio Hirano, Tsutomu Yasukawa, Yuichiro OguraDepartment of Ophthalmology and Visual Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, JapanAbstract: We present a case of retinitis pigmentosa with vitreoretinal traction-associated retinal detachment. The retinal detachment was detected in the nasal periphery. No retinal breaks and no active vascular leakage were observed by fundus scopy and fluorescein angiography, respectively. However, 8 months later, the tractional retinal detachment was spontaneously resolved with posterior vitreous detachment.Keywords: retinitis pigmentosa, vitreoretinal traction, retinal detachment

To report a novel method to quantify traction applied to the retina using vitreous cutters during pars plana vitrectomy.Fresh porcine eyes were positioned in a specially developed holder and transfixed to the retinal layers with a wire and the other end fixed to the load cell of a strain gauge. Five separate 20-gauge electrical drive mechanism vitrectors were introduced into the eye at a 45 degrees angle and positioned at a distance of either 3 or 5 mm from the retina. Data from the strain gauge were acquired and the traction force computed.The analysis revealed that the vitreoretinal traction increased by 7.90 dynes for each 100 mm Hg increase in vacuum (p0.05). The traction forces decreased by 2.51 dynes for each 500 cuts per minute increased (p0.05) and the traction force increased by 2.17 dynes at 3 mm compared with 5 mm (p0.05).The traction was directly proportional to the aspiration vacuum and inversely proportional to the cut rate. The cutter traction force increased with proximity to the retina.