Prospective Retinal and Optic Nerve Vitrectomy Evaluation (PROVE) Study

Effect of modified surgical conditions on the peripapillary microvasculature and RNFL in patients receiving vitrectomy: an OCTA study

PURPOSE

Pars plana vitrectomy (PPV) is an effective treatment of vitreoretinal diseases, while some studies reported visual field defects after surgery. The aim of this study was to evaluate the protective effects of modified vitrectomy surgical conditions on peripapillary microvasculature and retinal nerve fiber layer (RNFL) changes using optical coherence tomography angiography (OCTA).

METHODS

This was a retrospectively study and the medical records of 37 patients diagnosed with iERM or iMH underwent PPV with ILM peeling were retrospectively reviewed. Patients were divided into two groups according to different surgical conditions. Peripapillary OCTA images were acquired at pre-operation, 1 week, 1 month, and 3 months post-operation. Best corrected visual acuity (BCVA) was recorded. Intraocular pressure (IOP) was measured with Goldman applanation tonometer. Fisher's exact test, the Mann-Whitney U test, t test, and repeated-measures analysis of variance (RM-ANOVA) were used to analyze our data.

RESULTS

The primary metrics found was the radial peripapillary capillary (RPC) small vessel density. The RPC in the protective group was significantly increased compared with the control group after surgery. At 3 months after vitrectomy, the mean and superior quadrant peripapillary RNFL thickness in the protective group was significantly higher than those in the control group. BCVA was improved in both groups at 3 months after surgery. BCVA and IOP did not differ significantly between these two groups pre- and post-operation.

CONCLUSION

Vitrectomy with ILM peeling may cause peripapillary microvascular and RNFL damage. The application of a modified surgical conditions may do some help in the recovery of peripapillary blood flow and peripapillary RNFL thickness.

Peripapillary and Macular Optical Coherence Tomography Angiography Predictors of Visual Improvement in Patients Treated with Vitrectomy for Idiopathic Epiretinal Membrane

INTRODUCTION

We investigated the changes of peripapillary and macular microvasculature in idiopathic macular epiretinal membrane (iERM) eyes before and after pars plana vitrectomy (PPV), aiming to identify potential optical coherence tomography angiography (OCTA) predictors of visual acuity improvement.

METHODS

Fifty-seven eyes diagnosed with iERM were enrolled and underwent PPV with ERM and internal limiting membrane (ILM) peeling. Data were collected before surgery and during the 12-month postoperative period. OCTA analysis focused on radial peripapillary capillary (RPC) vessel density (VD), superficial and deep capillary plexus (SCP and DCP, respectively). Functional and OCT structural outcomes, including best-corrected visual acuity (BCVA) and macular thickness, were also recorded.

RESULTS

Multivariate linear regression analysis revealed that higher preoperative RPC VD, lower SCP VD, and lower BCVA were predictors of postoperative BCVA improvement (p < 0.001, p = 0.047, and p < 0.001, respectively). Throughout the follow-up period, there was an observed increase in intradisc RPC VD, whole-disc VD, and parafoveal DCP VD (all p < 0.001). BCVA and central macular thickness demonstrated significant improvement (p < 0.001) within the first month following vitrectomy, which then stabilized from the third month onward.

CONCLUSIONS

Preoperative microvascular measurements in iERM patients can forecast postoperative BCVA. OCTA findings reveal that both increased RPC density and reduced SCP density at baseline could serve as predictors of better visual outcomes after surgery. Enhanced RPC density may reflect a healthier optic nerve with greater potential for visual recovery, while a less dense SCP could indicate less iERM contraction, both contributing to more favorable postoperative visual results.

Increased late-onset glaucoma risk following vitrectomy for macular pucker or hole

OBJECTIVES

The long-term risk of developing glaucoma after vitrectomy remains uncertain. This retrospective population-based cohort study aimed to explore this risk following vitrectomy for macular pucker or hole.

METHODS

Utilizing Taiwan's National Health Insurance Research Database (NHIRD), we included patients who were older than 18 years and had undergone vitrectomy surgery between 2011 and 2019. Exclusions were made for patients with prior diagnoses of glaucoma, congenital or secondary glaucoma, as well as those who had received previous vitreoretinal treatments or had undergone multiple vitrectomies.

RESULTS

After an average follow-up period of 51 and 53 months respectively for the vitrectomized and non-vitrectomized group, our results showed a relative risk of 1.71 for glaucoma development in the vitrectomized group. Higher adjusted hazard ratios were also observed for open-angle glaucoma and normal tension glaucoma. Increased risks were associated with male sex, obstructive sleep apnoea, and migraine. In the subgroup analysis, phakic eyes at baseline and those who had undergone cataract surgery post-vitrectomy were associated with a lower risk of glaucoma development during follow-up. Among all glaucoma events, pseudophakic status at baseline had the shortest interval to glaucoma development following vitrectomy.

CONCLUSIONS

These findings underscore the potential relationship between vitrectomy and glaucoma onset, emphasizing the need for vigilant monitoring and early detection of glaucoma in post-vitrectomy patients.

Long-Term Changes in Retinal Nerve Fiber Layer Thickness after Vitrectomy for Epiretinal Membrane Using Optical Coherence Tomography Images

This study investigated the long-term effects of epiretinal membrane (ERM) surgery on peripapillary retinal nerve fiber layer (RNFL) thickness using optical coherence tomography (OCT) images. We included 30 patients with idiopathic ERM who underwent a vitrectomy for ERM removal with internal limiting membrane peeling. The patients were followed up for 5 years after surgery, and their medical records were reviewed for best-corrected visual acuity (BCVA) and OCT parameters. The study population comprised 24 females (80.0%), and the mean age was 65.4 ± 7.2 years. The baseline BCVA significantly improved from 0.28 ± 0.24 to 0.12 ± 0.09 logMAR (p < 0.001) 1 year after surgery and continued to improve for 5 years after surgery. The peripapillary RNFL thickness initially increased after surgery and then gradually decreased. The peripapillary RNFL thicknesses of the global and temporal sectors showed significant reductions 2 years after surgery, whereas those of the nasal sectors did not significantly change. The peripapillary RNFL thickness was thinner in the global and temporal areas of the operated eyes than in those of the fellow eyes 4 and 5 years after surgery. In conclusion, peripapillary RNFL thicknesses decreased in the global and temporal areas after ERM surgery, whereas peripapillary RNFL thicknesses in the nasal sectors did not change significantly during the long-term follow-up.

Peripapillary microvasculature changes after vitrectomy in epiretinal membrane via swept-source OCT angiography

PURPOSE

To evaluate the peripapillary microvasculature changes in patients with epiretinal membrane (ERM) following pars plana vitrectomy (PPV) with internal limiting membrane (ILM) peeling using swept-source optical coherence tomography angiography (SS-OCTA).

METHOD

Medical records and multimodal imaging data of 33 eyes after PPV for ERM were retrospectively reviewed. Peripapillary SS-OCTA images of 6×6 mm² were recorded at at pre- and post-operatively every 6 months for 1 year. A semi-automated method was used to analyzed SS-OCTA images, excluding the optic disc area, using the MATLAB software. The peripapillary vessel density (pVD) of superficial capillary plexus (SCP) and deep capillary plexus (DCP) was quantified in four quadrants (superior, inferior, nasal and temporal).

RESULT

The mean pVD in SCP and DCP decreased at 6- and 12-months follow-up. In sectoral analysis, superior, inferior, and temporal quadrants pVD in SCP and DCP were significantly reduced at 1 year after vitrectomy (all p < 0.05). Meanwhile, inferior quadrants pVD in SCP and DCP showed the earliest significant reduction at 6-months (p = 0.022 and 0.048, respectively). A reduction of post-operative mean pVD in DCP was significantly greater in patients with diabetic retinopathy (p = 0.043).

CONCLUSION

Peripapillary capillary density significantly decreased after surgical removal of ERM. Vitrectomy with ILM peeling can cause peripapillary microvascular damage starting in inferior sector.

The Postvitrectomy Cataract

To review the recent literature regarding risk factors for cataract formation after vitrectomy, the challenges and management strategies for anterior segment surgeons when facing post-vitrectomy cataract surgery, and the visual outcomes of patients undergoing post-vitrectomy cataract surgery. Cataract surgery after vitrectomy can be safely performed to significantly improve the visual outcome in most post-vitrectomy patients, although final visual acuity is primarily limited by the patient’s underlying vitreoretinal pathology.

OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY EVALUATION OF PERIPAPILLARY MICROVASCULAR CHANGES AFTER RHEGMATOGENOUS RETINAL DETACHMENT REPAIR

PURPOSE

To evaluate the radial peripapillary capillary plexus (RPCP) vessel density (VD) and the retinal nerve fiber layer (RNFL) thickness in eyes successfully treated with pars plana vitrectomy for primary rhegmatogenous retinal detachment.

METHODS

In this cross-sectional multicenter clinical study, eyes with a minimum 12-month follow-up were reexamined. The RPCP VD and RNFL thickness in the rhegmatogenous retinal detachment subfields of the affected eye (study group) were compared with the corresponding areas of the healthy fellow eyes (control group).

RESULTS

Fifty-three eyes were included in the study. A significantly lower RPCP VD and RNFL thickness were observed in those subfields affected by rhegmatogenous retinal detachment compared with those of the control group (P < 0.001). No statistically significant differences were observed between undetached subfields in the study group and their corresponding images in the control group. In the study group, a significant correlation was found between RPCP VD and RNFL thickness in subfields with detached retina (r = 0.393, P < 0.001) and undetached retina (r = 0.321, P < 0.001).

CONCLUSION

Radial peripapillary capillary plexus VD changes were found in the subfields of detached retina successfully treated with pars plana vitrectomy and they correlated with RNFL thinning. These data suggest a coexistence of neuronal and microvascular damage in patients affected by rhegmatogenous retinal detachment.

Tomographic Structural Changes of the Inner Retina after Internal Limiting Membrane Peeling for Idiopathic Epiretinal Membrane

Purpose

To investigate the tomographic structural changes in the retinal layers after internal limiting membrane (ILM) peeling for idiopathic epiretinal membrane (ERM).

Methods

Sixty-nine eyes treated with vitrectomy and ILM peeling for idiopathic ERM were analyzed. Parafoveal retinal thickness was measured at baseline and 6 months after surgery.

Results

Total retinal thickness decreased significantly in the nasal and temporal subfields after surgery (p < 0.001), whereas the inner nuclear layer and outer nuclear layer showed nasal thickening (all, p < 0.001). The postoperative temporal/nasal subfield thickness ratio of each layer was significantly lower than that of fellow eyes. Eyes with larger ILM peeling showed a significantly lower temporal/nasal subfield thickness ratio (p = 0.033) than those with smaller sizes.

Conclusions

The retinal thickness of each layer showed anatomical changes from ILM peeling and ERM removal. Nasal parafoveal thickening and temporal thinning occurred in the inner retinal architecture, which might be affected by ILM peeling size.

Long-Term Intraocular Pressure Changes after Pars Plana Vitrectomy: An 8-Year Study

Purpose:

To investigate the long-term changes of intraocular pressure (IOP) after pars plana vitrectomy (PPV).

Methods:

This was a retrospective historical cohort study. Patients with a history of vitrectomy in one eye by a single surgeon were enrolled. IOP of the operated eye was compared to the fellow eye. Previous scleral buckling, IOP rise due to surgical/anatomic complications, silicone oil (SO) emulsification, and contralateral ocular hypertension/glaucoma at recruitment were exclusion criteria. “Significant IOP rise” (>6.0 mmHg) and development of open angle glaucoma (OAG) were the main outcome measures.

Results:

Two hundred and twenty-five eyes were included. Mean and median follow-up duration were 20.6 and 9.0 months, respectively. Mean baseline IOP and mean final IOP were 13.53 ± 3.75 mmHg and 16.52 ± 6.95 mmHg, respectively (P < 0.001). Forty-three patients developed “significant IOP rise” with no statistically significant relation to the indication of vitrectomy, the postoperative lens status, and number of vitrectomies (P = 0.410, P = 0.900, and P = 0.160, respectively). SO injection raised the probability of IOP rise in the long-term (P = 0.028). OAG occurred in 17 patients (7.5%) with no association to SO tamponade (P = 0.840). “Significant IOP rise” and OAG occurred in 3 and 1 control eyes, respectively, significantly lower than the rates in study eyes (P < 0.001).

Conclusion:

Mean IOP slightly rose in the long-term after PPV. SO tamponade was associated with IOP rise in the long-term but not with the incidence of OAG. Both IOP rise and OAG were more probable after vitrectomy.

Pars Plana Vitrectomy and the Risk of Ocular Hypertension and Glaucoma: Where Are We?

Purpose is to review the pathogenic mechanism for ocular hypertension and glaucoma development after pars plana vitrectomy. Both acute and chronic causes are considered, and special attention is paid to the theories and clinical evidence on the risk of developing Open Angle Glaucoma (OAG) after Pars Plana Vitrectomy (PPV). Most existing scientific literature on the issue agree on the role of ascorbate as an oxygen scavenger within the vitreous chamber. Oxygen tension in the vitreous and anterior chamber is maximum inn proximity of the retinal surface and endothelium, respectively and steeply decreases toward the lens, on both sides, and trabecular meshwork. Vitreous removal and, to a lesser extent, liquefaction, greatly reduces oxygen tension gradient in vitreous chamber while cataract extraction has similar effects on anterior chamber oxygen gradients. Oxygen derivatives originated from the cornea and retina are actively reduced by the vitreous gel and/or the crystalline lens. Vitreous removal and cataract extraction reduce drastically this function. Most reported clinical series confirm this hypothesis although protocol difference and follow-up length greatly impact the reliability of results.

Influence of pars plana vitrectomy for macular surgery on the medium term intraocular pressure

Purpose

To evaluate the long-term effect of 20 and 23 gauge pars plana vitrectomy (PPV) on intraocular pressure (IOP).

Methods

Study type: Monocentric retrospective cohort study. 249 eyes of 249 patients undergoing PPV due to epiretinal membrane (EM), idiopathic macular hole (IMH) or vitreoretinal traction (VT) were included. The fellow eye served as control. Exclusion criteria were factors known to influence the IOP, such as cataract surgery during follow-up, extended use of steroids, cryotherapy and silicone oil endotamponade. The relative change of IOP (operated vs. fellow eye) at 6–12 months after surgery was defined as primary endpoint. Secondary endpoints were the relative change of IOP at 3–6 and 12–24 months. Possible influencing cofactors were analysed using ANCOVA.

Results

The primary endpoint did not show a significant IOP reduction of the operated eye relative to the fellow eye (P = 0.089, n = 84). However, the IOP of the operated eye alone was significantly reduced at 6–12 and 12–24 months after surgery (-0.75 ± 2.80 and -1.22 ± 3.29 mmHg, P = 0.008 and 0.007, respectively). The IOP of the fellow eye was also significantly reduced at the 12–24 months period (-0.75 ± 2.73 mmHg, P = 0.008). In the subgroup analysis, sclerotomy size was a significant influencing cofactor, leading to lower IOP after 20G compared to 23G vitrectomy (P = 0.04).

Conclusion

Pars plana vitrectomy did not induce a significant long-term IOP reduction relative to the contralateral eye. However, we observed a IOP lowering potential in 20G vitrectomy.

Influence of Epiretinal Membranes on the Retinal Nerve Fiber Layer Thickness Measured by Spectral Domain Optical Coherence Tomography in Glaucoma

PURPOSE

We investigated changes in the thickness of the peripapillary retinal nerve fiber layer (RNFL) following the onset of an epiretinal membrane (ERM) in glaucoma patients.

METHODS

Among regularly monitored glaucoma patients, patients with a newly diagnosed ERM were consecutively enrolled. Before and after the onset of ERM, the RNFL thickness was measured using spectral domain optical coherence tomography, and a visual field examination was performed using a Humphrey field analyzer. Changes in RNFL thickness parameters and global indices of the visual field analyzer were assessed.

RESULTS

In a total of 28 eyes from 28 patients, the average RNFL thickness increased by a mean of 4.0 ± 7.4 μm (p = 0.009) after ERM onset. There was an increase in the superior, nasal, and temporal quadrant RNFL thicknesses, and the change in the temporal RNFL thickness was significant (14.4 ± 21.2 μm, p < 0.001). However, the inferior RNFL thickness decreased by -0.6 ± 7.5 μm (p = 0.116). In the visual field examination, the mean deviation decreased significantly by -0.8 ± 1.7 dB (p = 0.038), from -14.6 to -15.4 dB.

CONCLUSIONS

A significant increase in average RNFL thickness was detected following ERM onset in glaucoma patients, although there was deterioration of the mean deviation in the visual field. When ERM occurs in glaucoma patients, clinicians should be aware that RNFL thickness measurements obtained with a spectral domain optical coherence tomography may underestimate the status of glaucomatous optic neuropathy.

Choroidal thickness and intraocular pressure after 25-gauge and 23-gauge vitrectomy for idiopathic epiretinal membrane

PURPOSE

To determine the relationship between the subfoveal choroidal thickness (SCT) and intraocular pressure (IOP) following 25-gauge (25G) and 23-gauge (23G) vitrectomy for idiopathic epiretinal membrane (ERM).

STUDY DESIGN

Retrospective, consecutive, interventional case series.

METHODS

Sixty-two patients undergoing 25G vitrectomy and 56 patients undergoing 23G vitrectomy for ERM participated. SCT was measured using enhanced depth imaging optical coherence tomography and IOP were measured both at baseline and postoperatively.

RESULTS

In both groups, the IOPs on day one and one week after surgery were significantly lower than at baseline (P < 0.001 for both). The rates of changes of IOP were significantly greater in 23G compared to 25G on day one (P = 0.026). In 23G the SCTs on day one and one week after surgery were significantly thicker (P < 0.001) than baseline. The rates of changes in SCT between baseline and day one negatively correlated with those of IOP in 23G (r = -0.559, P < 0.001) but no correlation was observed with 25G (r = -0.129, P = 0.316).

CONCLUSION

Choroidal thickness increases soon after 23G vitrectomy for ERM which is probably due to the transient hypotony, however, early SCT change does not appear in 25G vitrectomy. Twenty-five-gauge vitrectomy may have an advantage in minimizing postoperative choroidal changes.

Intraocular Oxygen and Antioxidant Status: New Insights on the Effect of Vitrectomy and Glaucoma Pathogenesis

PURPOSE

The purpose of this study was to investigate correlations of partial pressure of oxygen (pO₂) in the ocular anterior segment of human eyes and aqueous humor antioxidant levels of ascorbate (AsA) and total reactive antioxidant potential (TRAP) with glaucoma and vitreous status.

METHODS

This prospective, cross-sectional study stratified patients (n = 288 eyes) by lens and vitreous status and the presence of primary open-angle glaucoma for statistical analyses. Intraocular pO₂ concentrations were measured using a fiberoptic probe in patients at the beginning of planned glaucoma and/or cataract surgery. Aqueous humor specimens were obtained for antioxidant analysis of AsA and TRAP.

RESULTS

Following prior pars plana vitrectomy, pO₂ levels were significantly higher than in the reference group of cataract surgery in the anterior chamber angle (16.2 ± 5.0 vs. 13.0 ± 3.9 mm Hg; P = .0171) and in the posterior chamber (7.6 ± 3.1 vs. 3.9 ± 2.7 mm Hg; P < .0001). AsA and TRAP levels were significantly lower (1.1 ± 0.4 vs. 1.4 ± 0.5 mM, respectively; 403.3 ±116.5 vs. 479.0 ± 146.7 Trolox units, respectively; P = .004 and P = .024, respectively) in patients after vitrectomy. In patients with an intact vitreous, neither pO₂ nor antioxidant status correlated with lens status or glaucoma.

CONCLUSIONS

Increased pO₂ and antioxidant depletion following vitrectomy suggests an alteration of the intraocular oxidant-antioxidant balance. Our study links physiologic factors such as increased pO₂ in the anterior chamber angle and the posterior chamber to decreased antioxidant levels in aqueous humor following vitrectomy. Oxidative stress/damage to the trabecular meshwork in such post-vitrectomy cases may contribute to intraocular pressure elevation and increased risk of glaucoma. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Three-Year Findings on Intraocular Pressure Changes in The Prospective Retinal and Optic Nerve Vitrectomy Evaluation (PROVE) Study

BACKGROUND AND OBJECTIVE

This paper reports 3-year intraocular pressure (IOP) outcomes of the Prospective Retinal and Optic Nerve Vitrectomy Evaluation (PROVE) study.

PATIENTS AND METHODS

The prospective, controlled, observational study included 80 eyes of 40 participants undergoing routine pars plana vitrectomy. Study patients underwent preoperative evaluation and multimodal testing of the study (surgical) and fellow (control) eye. This testing was repeated at 3 months postoperatively and then annually for 3 years.

RESULTS

Thirty-two of 40 patients (80%) completed 3-year follow-up. At 3 years postoperatively, there was no difference in IOP measurements in surgical eyes overall from baseline (P = .36). Subgroup analysis of pseudophakic eyes at baseline showed a significant elevation in IOP from 14.3 mm Hg ± 2.9 mm Hg at baseline to 16.8 mm Hg ± 3.2 mm Hg at 3-year follow-up (P < .029). Fellow eyes did not experience a significant change from baseline.

CONCLUSION

The authors' 3-year results show that IOP is consistently and significantly elevated in pseudophakic eyes compared to baseline following routine vitrectomy. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:371-376.].

Correlation between choroidal thickness and intraocular pressure after 23-gauge vitrectomy for idiopathic epiretinal membrane

AIM

To determine the relationship between the subfoveal choroidal thickness (CT) and intraocular pressure (IOP) following idiopathic epiretinal membrane (ERM) surgery.

METHODS

Retrospective observational case series of patients who had undergone 23-gauge vitrectomy for an ERM. The measurements of CT and IOP were done at the baseline and 1d, 1wk, 1, 3, 6, and 12mo after the surgery.

RESULTS

Forty-four eyes of 43 patients with a mean age of 69.8±9.5y were studied. The CT was 200.8±86.3 µm at the baseline, 210.1±83.5 µm at 1d, 213.2±85.4 µm at 1wk, 203.1±84.0 µm at 1mo, 197.5±85.5 µm at 3mo, 197.7±84.0 µm at 6mo, and 191.2±86.8 µm at 12mo after surgery. The CT on day 1 and week 1 after the surgery was significantly thicker than that at the baseline CT (P=0.0023 and P<0.0001). The CT at 12mo after surgery was significantly thinner than the baseline (P=0.0062). The IOP on day 1 and week 1 were significantly lower than the baseline (P<0.0001 and P=0.0042). The IOP at 1, 3, 6, and 12mo after surgery were significantly higher than the baseline IOP (P=0.0087, P=0.0023, P<0.00051, and P<0.0001). The rates of changes in the CT between baseline and day 1 and week 1 were significantly and negatively correlated with the rates of change in the IOP (P<0.0001 and P=0.046). In the group with the IOP change rate of -30% or less at 1d postoperatively, the change rate of CT was -21.1% to 31.2% (9.8%±12.4%) and in the group of -29% or more, it was -8.9% to 28.0% (2.6%±8.9%). The change rate of CT in the group with the IOP change rate of -30% or less was significantly higher than the group of -29% or more (P=0.016).

CONCLUSION

CT increases soon after the ERM surgery which is probably due to the transient hypotony, showing that IOP may be a significant confounding factor for CT.

The Risk of Primary Open-Angle Glaucoma Following Vitreoretinal Surgery-A Population-based Study

PURPOSE

To determine the risk of primary open-angle glaucoma (POAG) following vitreoretinal surgery.

DESIGN

Retrospective, population-based cohort study.

METHODS

All residents of Olmsted County, Minnesota, undergoing scleral buckle and/or vitrectomy between 2004 and 2015 were included in the operative cohort. The fellow nonoperative eyes were included in the comparison cohort. The study and comparison cohorts consisted of 344 and 277 eyes, respectively. The main outcome measure was the development of POAG. Secondary glaucomas were excluded. The probability of glaucoma in operative eyes and nonoperative fellow eyes was compared. The observed rate of POAG in the operative eyes was also compared to the rate of POAG in the population of Olmsted County.

RESULTS

The mean age was 64.7 years and the median follow-up period was 4.9 years. There were 58, 57, and 229 study eyes in the scleral buckle, scleral buckle with vitrectomy, and vitrectomy only cohorts, respectively. The 10-year cumulative probability of developing glaucoma was significantly greater in the operative group (8.9%, 95% confidence interval [CI] 3.8%-14%) compared to the nonoperative group (1.0%, 95% CI 0-2.4%; P = .02). None of the eyes in the scleral buckle group developed glaucoma. The 10-year probability of POAG was 17.5% (95% CI 0-34.9%) and 10.0% (95% CI 3.0%-17.0%) in the scleral buckle with vitrectomy and vitrectomy alone cohorts, respectively. The rates of POAG in operative eyes undergoing scleral buckle with vitrectomy and vitrectomy alone were significantly greater than the rate of POAG for the Olmsted County general population (1.0%, P < .001).

CONCLUSIONS

The risk of POAG is increased after vitrectomy.

OCULAR HYPERTENSION AND GLAUCOMA FOLLOWING VITRECTOMY: A Systematic Review

PURPOSE

Pars plana vitrectomy has been reported to increase the risk of ocular hypertension and open-angle glaucoma. The authors conducted a systematic review of randomized and nonrandomized studies to compare the incidence of open-angle glaucoma and ocular hypertension in vitrectomized versus nonvitrectomized eyes.

METHODS

A literature search was performed using MEDLINE and EMBASE until August 2016. Data on ocular hypertension and open-angle glaucoma incidence and mean intraocular pressure after at least 1 year were pooled using random-effects metaanalysis models. Because only nonrandomized studies were retrieved, ROBINS-I tool was used to assess risk of bias in the review.

RESULTS

Seven included studies had a paired design to compare the outcomes of vitrectomized versus fellow eyes, with mean follow-up of least 12 months. Four studies (851 patients) provided data on open-angle glaucoma: incidence in vitrectomized versus non-vitrectomized eyes was 7.8% and 4.8%, respectively, yielding a metaanalytic odds ratio of 1.67 (95% CI: 1.08-2.57). Six studies (1,060 patients) reported on the occurrence of ocular hypertension, which was 5.8% in vitrectomized eyes versus 3.1% in fellow eyes (odds ratio: 2.03, 95% CI: 0.97-4.22), without significant differences in the mean postoperative intraocular pressure (mean difference 0.31 mmHg, 95% CI: -0.26 to 0.89).

CONCLUSION

Although the review found increased risk of open-angle glaucoma with pars plana vitrectomy, the studies were heterogenous or inconsistent regarding ocular hypertension and intraocular pressure increase. Larger studies should be conducted in homogenous cohorts of patients undergoing macular surgery, excluding complex conditions such as retinal detachment or diabetic retinopathy.

PERIPAPILLARY RETINAL NERVE FIBER THICKNESS CHANGES AFTER VITRECTOMY FOR EPIRETINAL MEMBRANE IN EYES WITH AND WITHOUT VITREOUS DETACHMENT

PURPOSE

To compare the changes in postoperative peripapillary retinal nerve fiber layer (p-RNFL) thickness after vitrectomy for epiretinal membrane in eyes with preexisting posterior vitreous detachment (PVD) and eyes with surgically induced PVD.

METHODS

This study included consecutive patients who underwent 25-gauge vitrectomy for epiretinal membrane. Eyes were divided, according to intraoperative PVD status, into a preexisting PVD group and surgically induced PVD group. Best-corrected visual acuity, p-RNFL thickness, and central retinal thickness were performed before and at 1, 3, and 6 months after surgery.

RESULTS

One hundred and twenty eyes of 120 patients were enrolled: 64 eyes in the preexisting PVD group and 56 eyes in the surgically induced PVD group. In the preexisting PVD group at 6 months, the mean global p-RNFL thickness did not change, whereas it was reduced in the temporal sector (P = 0.034). In the surgically induced PVD group at 6 months, significant decreases were observed in global p-RNFL thickness (P = 0.027), temporal (P = 0.021), temporal inferior (P = 0.030), and nasal inferior sectors (P = 0.010). At 6 months, the two groups differed significantly in temporal (P < 0.001) and temporal inferior sectors (P = 0.004). The preoperative mean best-corrected visual acuity improved significantly at 6 months in both groups.

CONCLUSION

Postoperative p-RNFL thickness after vitrectomy for epiretinal membrane tended to decrease in the temporal sector in all eyes and in the temporal inferior and nasal inferior sectors in eyes with surgically induced PVD.

Effects of Vitrectomy and Lensectomy on Older Rhesus Macaques: Oxygen Distribution, Antioxidant Status, and Aqueous Humor Dynamics

Purpose

The purpose of this study is to evaluate effects of vitrectomy (PPV) and lens extraction with intraocular lens implantation (PE/IOL) on molecular oxygen (pO₂) distribution, aqueous humor antioxidant–oxidant balance, aqueous humor dynamics, and histopathologic changes in the trabecular meshwork (TM) in the older macaque monkey.

Methods

Six rhesus monkeys underwent PPV followed by PE/IOL. pO₂, outflow facility, and intraocular pressure (IOP) were measured. Aqueous and vitreous humor specimens were analyzed for antioxidant status and 8-hydroxy-2′-deoxyguanosine (8-OHdG), a marker of oxidative damage. TM specimens were obtained for immunohistochemical and quantitative PCR analysis.

Results

pO₂ at baseline revealed steep gradients in the anterior chamber and low levels in the posterior chamber (PC) and around the lens. Following PPV and PE/IOL, pO₂ significantly increased in the PC, around the IOL, and angle. IOP increased following both surgical interventions, with no change in outflow facility. Histopathologic analysis did not show changes in TM cell quantification, but there was an increase in 8-OHdG. Quantitative PCR did not reveal significant differences in glaucoma-related gene expression. Aqueous and vitreous humor analysis revealed decreased ascorbate and total reactive antioxidant potential and increased 8-OHdG in the aqueous humor only in the surgical eyes.

Conclusions

Oxygen distribution in the older rhesus monkey is similar to humans at baseline and following surgical interventions. Our findings of histopathologic changes of TM oxidative damage and alterations in the oxidant-antioxidant balance suggest a potential correlation of increased oxygen exposure with oxidative stress/damage and the development of open angle glaucoma.

Visual field changes after vitrectomy with internal limiting membrane peeling for epiretinal membrane or macular hole in glaucomatous eyes

Purpose

To investigate visual field changes after vitrectomy for macular diseases in glaucomatous eyes.

Methods

A retrospective review of 54 eyes from 54 patients with glaucoma, who underwent vitrectomy for epiretinal membrane (ERM; 42 eyes) or macular hole (MH; 12 eyes). Standard automated perimetry (Humphrey visual field 24–2 program) was performed and analyzed preoperatively and twice postoperatively (1^st and 2nd sessions; 4.7 ± 2.5, 10.3 ± 3.7 months after surgery, respectively). Postoperative visual field sensitivity at each test point was compared with the preoperative value. Longitudinal changes in mean visual field sensitivity (MVFS) of the 12 test points within 10° eccentricity (center) and the remaining test points (periphery), best-corrected visual acuity (BCVA), intraocular pressure (IOP), and ganglion cell complex (GCC) thickness, and the association of factors with changes in central or peripheral MVFS over time were analyzed using linear mixed-effects models. In addition, 45 eyes from 45 patients without glaucoma who underwent vitrectomy for epiretinal membrane (ERM; 34 eyes) or macular hole (MH; 11 eyes) were similarly examined and statistically analyzed (control group).

Results

In glaucomatous eyes, visual field test points changed significantly and reproducibly; two points deteriorated only at the center and twelve points improved only at the periphery. Central MVFS decreased (p = 0.03), whereas peripheral MVFS increased postoperatively (p = 0.010). In the control group, no visual field test points showed deterioration, and central MVFS did not change significantly after vitrectomy. BCVA improved, GCC thickness decreased, and IOP did not change postoperatively in both groups. The linear mixed-effects models identified older age, systemic hypertension, longer axial length, and preoperative medication scores of ≥2 as risk factors for central MVFS deterioration in glaucomatous eyes.

Conclusions

Visual field sensitivity within 10° eccentricity may deteriorate after vitrectomy for ERM or MH in glaucomatous eyes.

Transient Increase of Retinal Nerve Fiber Layer Thickness after Vitrectomy with ILM Peeling for Idiopathic Macular Hole

Purpose. The purpose of this study was to determine the long-term changes in the circumpapillary retinal nerve fiber layer (RNFL) thickness following macular hole surgery with internal limiting membrane (ILM) peeling combined with phacoemulsification. Methods. Thirty-eight eyes of 37 patients who had pars plana vitrectomy (n = 36) between 2010 and 2014 were studied. The average thicknesses of the global and the six sectors of the RNFL were determined before and at 1, 3, 6, 12, and 24 (n = 22) months (M) after the surgery by spectral-domain optical coherent tomography. The postoperative mean RNFL thickness at each time was compared to that before the surgery by paired t-tests. Results. The RNFL of the operated eyes was significantly thicker at 1 month (1 M) and 3 M in all but the inferior-nasal sectors. The significant increase remained until 12 M in the superior-temporal and superior-nasal sectors. In addition, the RNFL was also significantly thicker in the temporal-inferior sector at 12 M based on the findings in 38 eyes. Conclusions. The postoperative RNFL was thicker in all but the nasal-inferior sector for at least 12 M after surgery. This prolonged increase of the RNFL thickness may indicate damage and mild edema of the RNFL.

Small-incision 4-point scleral suture fixation of a foldable hydrophilic acrylic intraocular lens in the absence of capsule support

PURPOSE

To determine the visual outcomes and complications of a new small-incision technique for 4-point fixation of a hydrophilic acrylic posterior chamber intraocular lens (IOL) in the absence of capsule support.

SETTING

Three North American tertiary referral centers and a private practice.

DESIGN

Retrospective case series.

METHODS

Secondary IOL placement was performed from 2011 to 2014. Indications for surgery, clinical results, and complications were analyzed. Primary outcomes included postoperative corrected distance visual acuity (CDVA) and surgical complications.

RESULTS

Charts of 35 patients (37 eyes) were reviewed. The mean age at surgery was 56 years, and the mean follow-up was 6 months (range 3 to 24 months). Clinical indications included a dislocated IOL (30%), ocular trauma (19%), crystalline lens subluxation (19%), uveitis-glaucoma-hyphema syndrome (5%), post-complicated cataract (8%), congenital cataract (8%), and decompensated cornea (3%). The mean CDVA improved from 20/80 preoperatively to 20/40 postoperatively (P < .01). Thirty-six eyes (97%) had an improved or unchanged CDVA, and 1 eye (3%) had a reduced CDVA because of worsening glaucoma. Postoperative complications included ocular hypertension (24%), iritis (5%), wound leakage (3%), transient corneal edema (3%), glaucoma requiring a tube shunt (3%), and IOL dislocation (3%).

CONCLUSION

Small-incision 4-point scleral fixation of the Akreos AO60 hydrophilic acrylic IOL in the absence of capsule support appears to be a safe and effective technique for secondary IOL placement.

FINANCIAL DISCLOSURES

Drs. Berdahl and Ayres are consultants to Bausch & Lomb, Inc. Drs. Ayres and Fram have received speaker fees from Bausch & Lomb. Dr. Terveen does not have a financial or proprietary interest in any material or methods mentioned.

Effect of vitreomacular adhesion and vitreous gel on age-related reduction of macular thickness: a retrospective observational study

OBJECTIVE

To investigate the effects of vitreomacular adhesion (VMA), vitreomacular separation (VMS) and absence of vitreous gel due to vitrectomy on macular thickness measured in the spectral domain optical coherence tomographic (SD-OCT) images.

DESIGN

A longitudinal, retrospective, observational study.

SETTING

Secondary multicentre study.

PARTICIPANTS

218 eyes of 218 healthy patients and 119 vitrectomised eyes of 119 patients were studied. The healthy individuals were classified into a VMA group (54 eyes) and a VMS group (164 eyes), while the vitrectomised patients were classified into an internal limiting membrane (ILM)-on group (26 eyes) and an ILM-off group (93 eyes). In all participants, 2 Cirrus HD-OCT recordings were made with an average interval of 36 months (range 24-60 months).

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome measure was the rate of change in macular thickness in the central sector. The secondary outcomes were the rates of change in macular thickness in the inner 4 sectors.

RESULTS

The annual rate of change in the macular thickness of the central sector was 0.76±1.8 µm/year in the VMA group, -0.58±2.3 µm/year in the VMS group, -1.57±1.9 µm/year in the ILM-on group and -0.86±3.1 µm/year in the ILM-off group. There was a significant difference between the rate of the central sector thickness change in the VMA and VMS groups (p=0.0001). The presence of VMA was a significant factor associated with an increase in the central sector thickness (p=0.0055). When the healthy and ILM-on groups were compared, the rate of decrease in the central sector thickness was faster in the ILM-on group (p=0.0043). Multiple regression analyses showed that not peeling the ILM during the vitrectomy was a significant factor associated with a decrease in the central sector thickness (p=0.044).

CONCLUSIONS

The presence of a VMA and a vitreous gel may help restrain the macular thickness reduction.

Peripapillary RNFL Thickness Changes Evaluated with Spectral Domain Optical Coherence Tomography after Uncomplicated Macular Surgery for Epiretinal Membrane

PURPOSE

To evaluate the peripapillary RNFL (p-RNFL) thickness changes after vitrectomy for epiretinal membrane (ERM). The relationship between p-RNFL thickness change and visual function was assessed.

METHODS

Thirty-five eyes from 35 patients with ERM who underwent vitrectomy with internal limiting membrane (ILM) removal were included. Average p-RNFL and the four quadrants thickness were measured by spectral-domain optical coherence tomography (SD-OCT) before and at one, three, and six months after surgery.

RESULTS

At six months after surgery, p-RNFL thickness of the temporal and inferior quadrant was decreased in the operated eyes compared with fellow eyes (p<0.05). Pattern standard deviation (PSD) was higher than that of fellow eyes (p = 0.002). The temporal and inferior quadrant p-RNFL thickness showed a relationship with both best-corrected visual acuity (BCVA) outcome and the six-month PSD (p<0.05, respectively).

CONCLUSIONS

The selective decrease in the temporal and inferior p-RNFL thickness after vitrectomy for ERM removal could indicate inner retinal damage related to ILM peeling.

LONG-TERM FOLLOW-UP OF INTRAOCULAR PRESSURE AFTER VITRECTOMY IN EYES WITHOUT PREEXISTING GLAUCOMA

PURPOSE

To identify whether vitrectomy is associated with an increased risk of elevated intraocular pressure (IOP) and to report the incidence of open-angle glaucoma after vitrectomy.

METHODS

In this retrospective case series of 234 consecutive patients without a history of glaucoma or diabetes undergoing primary unilateral vitrectomy for an idiopathic epiretinal membrane or macular hole with a minimum of 2 years follow-up, mean IOP in operative and fellow eyes were compared at baseline and multiple postoperative times. Eyes were also assessed for the development of open-angle glaucoma.

RESULTS

The mean baseline IOP was 14.91 mmHg, and the mean final IOP was 14.6 (P = 0.278) in the operative eyes. Linear regression analysis of IOP in operative eyes from baseline to the final visit found an increase of 0.000047 mmHg per year compared with -0.00027 mmHg per year in the fellow eyes with no significant difference in the slope of the 2 regression lines (P = 0.27). Six vitrectomy eyes were diagnosed with new-onset open-angle glaucoma during a mean follow-up of 4.4 years; however, only one was not also diagnosed with glaucoma or ocular hypertension in the fellow unoperated eye.

CONCLUSION

Vitrectomy does not seem to be correlated with increased risk of IOP elevation or glaucoma development in comparison with fellow control eyes.