LONG-TERM TRENDS IN INTRAOCULAR PRESSURE AFTER PARS PLANA VITRECTOMY

Premacular membranes and glaucoma: a review of clinical and therapeutic considerations

PURPOSE

Primary epiretinal, or more precisely termed pre macular membranes (PMM) and glaucomatous optic neuropathy are both common conditions affecting a predominantly elderly population. There are several relevant clinical and pathological considerations when they are both diagnosed in the same eye.

METHODS

We systematically searched the literature to review the challenges clinicians must address when dealing with patients with co-existing PMM and glaucoma.

RESULTS

Although the current literature is limited there appears to be a link between the occurrence of glaucomatous optic neuropathy and idiopathic PMM. The presence of PMM can confound glaucomatous progression detection on optical coherence tomography (OCT). Vitrectomy and membrane peeling may improve vision in some patients with co-existing disease but there may be an increased risk of glaucoma progression particularly in eyes with advanced glaucoma and more extensive neuronal loss. Peeling of the retinal inner limiting membrane in addition to PMM peeling may result in an increased risk of visual loss. Inner nuclear layer hypo-reflective spaces on OCT are particularly prevalent in eyes with glaucoma and PMM and may be a negative prognostic sign for outcome.

CONCLUSION

Patients should be counseled regarding the guarded prognosis, and careful consideration given to the benefits of PMM surgery. Further research is needed to guide clinical practice.

Endothelial Cell Changes After Pars Plana Vitrectomy: A Cross-Sectional Study in a Tertiary Care Center

BACKGROUND

A wide variety of vitreoretinal diseases have been majorly treated by the use of pars plana vitrectomy (PPV) as the most commonly practiced treatment option. Despite the fact that it is the most feasible treatment modality, the probability of corneal endothelial cell damage following the treatment remains a matter of great concern. The study aims to inquire about the aftermath of PPV on endothelial cell density (ECD) and spans a time period of six months after the surgery has been performed.

METHODOLOGY

This cross-sectional study involved 20 patients who underwent PPV at Layton Rahmatullah Benevolent Trust (LRBT) Hospital Township, Lahore, Pakistan. ECD was measured using non-contact specular microscopy preoperatively and at 15 days, two months, and six months postoperatively. The main outcome measured was the change in ECD over time, and the results were analyzed using descriptive statistics via SPSS software (version 25.0, IBM Corp., Armonk, NY).

RESULTS

The mean baseline ECD was 2,421 cells/mm², which decreased to 2,185 cells/mm² by the six-month follow-up, representing an overall mean ECD loss of 13.72%. Significant reductions in ECD were observed at each postoperative time point, with the most substantial decrease occurring within the first two months post-surgery.

CONCLUSION

Corneal endothelial cells are substantially influenced by PPV, which is significantly evident by the continuous reduction in ECD following surgery. The analysis calls attention to a careful and proper post-operative observation of corneal well-being is therefore required to alleviate likely endothelial damage along with the necessity of deliberate thinking while opting for the surgical techniques. The main focus of future studies should be on how to improve the current practices involving surgical procedures to ensure minimizing the loss of endothelial cells.

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.

CARING: Cannula for Alleviation of Retinal Injury Caused by Needle Fluidic Gashing

Infusion-related iatrogenic retinal breaks (IRBs) are a significant complication in vitrectomies, particularly when smaller-gauge cannulas are used during fluid infusion. Using two-dimensional finite element analysis (FEA), we analyzed forces exerted on the retina from different cannulas: traditional 25-gauge, 20-gauge, 23-gauge, and 27-gauge, then investigated four alternative new cannula designs: (A) oblique orifices, (B) external obstruction, (C) side ports, and (D) perpendicular orifices. The analysis revealed that the standard 25-gauge cannula had a force of 0.546 milli-Newtons (mN). Optimized cannulas demonstrated decreased forces: 0.072 mN (A), 0.266 mN (B), 0.417 mN (C), and 0.117 mN (D). While all the designs decrease fluid jet force, each has unique challenges: Design A may complicate manufacturing, B requires unique attachment techniques, C could misdirect fluid toward the lens and peripheral retina, and D requires a sealed trocar/cannula design to prevent unwanted fluid ejection. These four innovative cannula designs, identified with detailed engineering simulations, provide promising strategies to reduce the risk of IRBs during vitrectomy, bridging the gap between engineering insights and clinical application.

Outcomes of Anterior Chamber, Sulcus, and Pars Plana Glaucoma Drainage Device Placement in Glaucoma Patients

Purpose

To assess outcomes of anterior chamber (AC), sulcus, and pars plana (PP) glaucoma drainage device (GDD) placement in glaucoma patients. Patients and Methods. Retrospective evaluation of glaucoma patients who underwent GDD insertion in the AC, sulcus, or PP at Massachusetts Eye and Ear between November 2016 and May 2021. Patients who received AC, sulcus, and pars plana tubes were selected using simple random sampling, and the first 40 patients meeting inclusion criteria were analyzed. Main outcome measures were cumulative success probabilities from Kaplan-Meier (KM) analyses, intraocular pressure (IOP), medication burden, and complication rates.

Results

The PP group had a larger proportion of Ahmed GDDs and was younger on average with less severe glaucoma compared to patients with AC or sulcus tubes. The PP group had a higher proportion of mixed-mechanism glaucoma and lower proportion of primary open-angle glaucoma. With success defined as IOP reduction ≥20% and 5 < IOP ≤ 21 mm Hg, the Kaplan-Meier cumulative success probabilities for all three GDD locations were not significantly different. No significant differences were found in complication rates between all groups after 3 months. Patients with PP GDD had significantly lower medication burden than those with AC or sulcus GDDs up to 1.5 years postoperatively (1.7 ± 1.1, 3.0 ± 1.4, and 2.8 ± 1.2 for PP, AC, and sulcus, respectively; P=0.017).

Conclusion

PP GDDs may be more effective in lowering medication burden than AC or sulcus tubes without compromising long-term safety.

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.

[The role of vitreous body in pathogenesis of glaucoma]

This literature review provides modern information on the unique structure of the vitreous body, its functions, and its role in the pathogenesis of glaucoma, describes the features of the vitreous morphology and metabolism, notes its biomechanical and trophic functions, outlines its role in healthy hydrodynamics and hemodynamics of the eye, as well as in aqueous humor outflow. The review presents clinical observations on the association of pathological changes in the vitreous body with glaucoma development and examines the role of involutional changes in the vitreous in the pathogenesis of glaucoma. The article also discusses possible pathogenetic mechanisms of glaucoma development in terms of pathological changes in the vitreous.

LATE-ONSET OCULAR HYPERTENSION AFTER VITRECTOMY: A Multicenter Study of 6,048 Eyes

PURPOSE

To determine the incidence and risk factors for late-onset ocular hypertension (LOH) after vitrectomy.

METHODS

From the electronic medical records of consecutive patients who underwent primary vitrectomy, from January 2010 to December 2015, at 5 tertiary vitreoretinal centers in Italy, patient demographics, systemic, ophthalmic, operative, and postoperative data were drawn. Main outcome measure was the presence of LOH, defined as intraocular pressure >21 mmHg detected more than 2 months after vitrectomy on at least 2 consecutive visits.

RESULTS

Among 6,048 patients, LOH was found in 294 (4.9%) vitrectomized eyes and in 87 (1.4%) fellow eyes, (chi square; P < 0.001). Multivariable logistic regression showed that significant risk factors for developing LOH included intraoperative triamcinolone use (odds ratio [OR], 7.62; P < 0.001), longer axial length (OR, 1.55; P = 3.023), preoperative higher intraocular pressure (OR, 1.81; P = 0.003), and postvitrectomy pseudophakic/aphakic status (OR, 2.04; P < 0.001). Decision-tree analysis showed that the stronger predictor of LOH was intraoperative triamcinolone use (P < 0.001). Secondary predictors were a preoperative intraocular pressure more than 15 mmHg (P < 0.001) in eyes that use triamcinolone, and postvitrectomy pseudophakic/aphakic status (P = 0.007) in eyes that did not use triamcinolone.

CONCLUSION

Late-onset ocular hypertension occurred in 4.9% of vitrectomized eyes. The main risk factors were intraoperative use of triamcinolone and postvitrectomy pseudophakic/aphakic status.

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.

[Distinctive features of phacoemulsification in previously vitrectomized eyes]

The review presents the main pathogenetic mechanisms of cataract development in an avitic eye as well as anatomical and functional changes of the eye in the state of avitria. The authors have also analyzed distinctive behavior of such eyes during phacoemulsification and surgical techniques used to answer specific avitreal phenomena.

A relatively higher intraocular pressure set at the end of vitrectomy is associated with a more stable and rapid visual recovery for patients with vitreous haemorrhage

PURPOSE

To compare structural and functional improvements in patients with vitreous haemorrhage (VH) with different IOPs re-established at the end of pars plana vitrectomy (PPV).

METHODS

It is a prospective, randomized, comparative, interventional study. Ninety-five patients with nonclearing VH were randomized to receive PPV with normalized IOPs of 15 mmHg (Group I: 32 eyes), 25 mmHg (Group II: 32 eyes) and 35 mmHg (Group III: 31 eyes) at the end of surgery. The grade of vitreous opacity and best-corrected visual acuity (BCVA) on postoperative day 1, week 1, month 1 and month 3 were compared with a mixed model for repeated measures analysis.

RESULTS

All 3 groups achieved significant improvement on postoperatively in BCVA (p < 0.01) and vitreous opacity (p < 0.01) compared with the baseline. The group difference was significant at the end of week 1 and showed a trend of higher IOP set at the end of PPV with better anatomical (p < 0.01) and visual recovery (p < 0.01). However, at postoperative month 1 and month 3, equivalent anatomical (month 1: p = 0.56; month 3: p = 0.36) and visual outcomes (month 1: p = 0.16; month 3: p = 0.88) were obtained in the 3 groups. The average effect of IOP on BCVA (group II versus group III: effect size (ES): 0.41, p < 0.01; group I versus group III: ES: 0.66, p < 0.01) and vitreous opacity (group II versus group III: ES: 0.70, p < 0.01; group I versus group III: ES:1.09, p < 0.01) over the course of the study period was statistically significant. The only postoperative complication was recurrent VH in two patients allocating in group I and II, respectively.

CONCLUSIONS

A relatively higher IOP set at the end of vitrectomy resulted in a more stable and rapid recovery with fewer complications in patients with non-complex VH.

Anatomic and functional results of idiopathic macular epiretinal membrane surgery

AIM

To assess the impact of macular surgery on the functional and anatomic outcomes in patients with grade 2 epiretinal membrane (ERM), and the effect of internal limiting membrane (ILM) peeling on visual acuity and to analyze the long-term effect of pars plana vitrectomy (PPV) on intraocular pressure (IOP).

METHODS

Pseudophakic eyes (62 eyes) diagnosed as idiopathic grade 2 ERM with at least 6mo postoperative follow-up were included in this retrospective study. The fellow eye was nonvitrectomized. Patients were divided into two groups: group 1 (29 eyes) treated with ERM and ILM peeling and group 2 (33 eyes) with only ERM peeling. Preoperative and postoperative best corrected visual acuity (BCVA), slit-lamp, and a dilated fundus examination was performed. IOP was measured with Goldman applanation tonometer before, day 1 and first week and each visit after surgery. The incidence of significant IOP elevation was compared between vitrectomized eyes and nonvitrectomized fellow eyes.

RESULTS

Visual improvement was statistically significant and similar in both groups (P=0.008 in group 1, P=0.002 in group 2, P=0.09 inter-group). The amount of decrease in central macular thickness was statistically significant and similar in both groups (P=0.005 group 1, P=0.008 group 2, P=0.37 intergroup). At the final follow-up (14.1±9.6mo) the incidence of significant IOP elevation was 4% in vitrectomized eyes (three eyes) and 3% (two eyes) in the nonvitrectomized fellow eyes (P=0.12). Four eyes (12.1%) had recurrent ERM after a mean follow-up of 8.6±1.1mo in group 2, there was no recurrence in group 1 (P=0.01).

CONCLUSION

Recurrence of ERM may be decreased by ILM peeling during ERM surgery. However, it seems that ILM peeling do not affect the functional outcome and 23-gauge PPV alone do not have a significant effect on IOP.

Incidence and risk factors for intraocular pressure rise after transconjunctival vitrectomy

Purpose

To study the incidence and risk factors of raised intraocular pressures (IOPs) in the follow-up of transconjunctival sutureless vitrectomy (TSV).

Methods

A retrospective observational study was performed on 635 patients who underwent TSV under a single surgeon. The IOPs were recorded using a calibrated non-contact tonometer at seven postoperative visits, viz., day 1, 7 and 1, 3, 6 months, and 1 day and 1 month following silicone oil removal.

Results

IOP rise was seen in 24.25% (154) out of the 635 eyes studied. Among patients under 50 years of age, 37.73% had an IOP rise, compared to 21.55% above 50 years (Odds Ratio 2.206). Among males, 30.32% had an IOP rise, as compared to 15.98% females (OR 2.287). In eyes with retinal detachment, 49.16% had raised IOP (OR 5.435), and 24.05% with proliferative diabetic retinopathy (OR 1.780), as opposed to 15.38% with macular hole and 12.32% with epiretinal membrane. This was statistically significant (P < 0.001). In eyes with silicone oil, 34.9% developed a rise in IOP (OR 2.738) as compared to 11.94% of other surgeries (OR 0.697). This was statistically significant (P < 0.001).

Conclusion

We observed an increase in IOP postoperatively, more in those under 50 years, males and patients undergoing surgery for RD and PDR.

INTRAOCULAR PRESSURE OUTCOMES AFTER SURGERY FOR RHEGMATOGENOUS RETINAL DETACHMENT IN SCHWARTZ SYNDROME

PURPOSE

To study intraocular pressure (IOP) outcomes after surgery for rhegmatogenous retinal detachment in Schwartz syndrome.

METHODS

We reviewed records of 32 eyes of 32 patients with Schwartz syndrome (patients with rhegmatogenous retinal detachment, IOP above 21 mmHg, and open angles without angle recession, chronic steroid use or other secondary causes of increased IOP) who had undergone surgical treatment consisting of scleral buckling or vitrectomy. Intraocular pressure, number of medication, best-corrected visual acuity were compared at baseline and postsurgery visits and also studied association of various factors on long-term IOP.

RESULTS

The median duration of rhegmatogenous retinal detachment was 2 months, and the inter quartile range was 1 to 12 months. Follow-up was 15 months (inter quartile range: 7-33 months). Sixteen (50%) had prior ocular trauma. Baseline IOP was 35 ± 8 mmHg, and 12% (4/32) of patients were on IOP-lowering medication at presentation. At the final visit, mean IOP was 17 ± 6 mmHg and 59% patients (19/32) required additional IOP-lowering medication or surgery for IOP control.

CONCLUSION

Surgical management of rhegmatogenous retinal detachment resulted in significant reduction in IOP. At the final visit, 41% did not require any IOP-lowering medication or surgical intervention for IOP control.

Incidence and outcomes of ocular hypertension from rhegmatogenous retinal detachment surgery in the acute postoperative setting

Purpose

To determine the incidence of ocular hypertension following surgery for rhegmatogenous retinal detachment in the first 3 months postoperatively and to determine their outcomes in terms of visual acuity, control of IOP, and changes in cup:disc ratio.

Patients and methods

A single center prospective cohort study was done involving patients who underwent retinal surgery for rhegmatogenous retinal detachment. The patients were followed up for 3 months postoperatively and were monitored for development of ocular hypertension. The primary outcome measures were changes in IOP, visual acuity, and cup:disc ratio.

Results

Of the 52 eyes enrolled in the study, 19 eyes developed ocular hypertension in the first 3 months postoperatively, giving an incidence rate of 36.5% (95% CI, 48.9-76.0%). Analysis of mean IOP trends shows that most cases of IOP elevations occur in the first day postoperatively with a sustained elevation up to the first month and then returning to normal levels by the 3rd month. There is a significant increase in mean cup:disc ratio among patients who developed ocular hypertension (p=0.047). Visual acuity trends show that mean visual acuity significantly improved from baseline among cases who maintained normal IOP (p=0.002) as compared to those who developed ocular hypertension (p=0.97), although the difference in final visual acuity at the end of 3 months between groups was not statistically significant (p=0.30).

Conclusion

Ocular hypertension may complicate retinal reattachment surgery. Control of IOP in the acute setting is essential to prevent development of secondary glaucoma.

Short-term incidence and management of glaucoma after successful surgery for stage 4 retinopathy of prematurity

Purpose:

The purpose of this study is to describe the short-term incidence, clinical features, and management of glaucoma in children after successful surgery for stage 4 retinopathy of prematurity (ROP).

Methods:

The retrospective study included all eyes undergoing successful surgery for stage 4 ROP with good outcomes at a tertiary eye care center between June 2014 and June 2016. Cases developing postoperative glaucoma underwent examination under anesthesia for measurement of intraocular pressures (IOP), corneal diameters, Retcam-assisted fundus imaging, and gonioscopy. Outcomes of glaucoma management were evaluated.

Results:

Hundred eyes of 70 babies underwent successful surgery for stage 4 ROP (with postoperative attached retina, and minimal sequelae) with minimum follow-up of 15 months. Six eyes (6%) developed postoperative glaucoma. Of these, four eyes had undergone lens-sparing vitrectomy and two were managed with lensectomy and vitrectomy (LV). Median time duration for development of glaucoma after primary vitreous surgery was 17.5 weeks. Two cases could be managed with topical IOP-lowering agents alone, whereas four required filtering surgeries (trabeculotomy with trabeculectomy and 0.04% mitomycin C [MMC] application). Average IOP decreased from 25 ± 2.36 to 12.2 ± 2.05 mmHg at 12 months from glaucoma diagnosis.

Conclusion:

Glaucoma is a potential adverse event following successful vitreous surgery for stage 4 ROP. A combined trabeculotomy–trabeculectomy along with MMC gives favorable outcome.

The effect of multiple vitrectomies and its indications on intraocular pressure

Background

To assess the relationship between different indications for trans pars plana vitrectomies (PPV’s) and the intraocular pressure (IOP), and the effect of multiple PPV’s on the IOP. We also examined whether there were differences in the number of IOP-lowering medications or surgeries before and after PPV.

Methods

A retrospective study including all patients that underwent at least one PPV in the period from 2001 till 2014 at our clinic. Medical records of all patients were reviewed and clinically relevant data were entered in a database. Generalized estimating equations models for repeated measurements were used to examine the effect of the number of PPV’s on the IOP and on the risk of undergoing glaucoma surgery, for each of the indications for PPV.

Results

Of 1072 PPV’s 447 eyes fulfilled the inclusion criteria. The IOP increased with 3.0 mmHg after a PPV with indication retinal detachment (p < 0.001), but remained stable after PPV for epiretinal membrane (p = 0.555), macular hole (p = 0.695), and vitreous hemorrhage (p = 0.787). At the end of the follow-up period the number of IOP-lowering medications was significantly higher compared to baseline, except in the macular hole group (p = 0.103). Also, the number of eyes that underwent glaucoma surgery was significantly higher compared to the fellow (not-operated) eyes (p < 0.001). There was a significant association between the number of PPV’s and the final IOP for the indication retinal detachment (p = 0.009), and between the number of PPV’s and glaucoma surgery (odds ratio [95% confidence interval]: 2.60 [1.62–4.15]).

Conclusions

The IOP rises significantly after PPV with indication retinal detachment. This association was not found for other indications for PPV. Also, the risk of IOP-lowering surgeries was higher after PPV, but not different between the PPV indications. The IOP should be monitored carefully after PPV, since there may be a higher risk of secondary glaucoma.

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.].

Positional Intraocular Pressure of Vitrectomized and Normal Fellow Eyes

Purpose

To compare posture-induced intraocular pressure (IOP) changes in vitrectomized eyes and normal eyes of patients who had vitrectomy in one eye.

Methods

A total of 31 patients older than 20 years of age who underwent vitrectomy were enrolled in the study. At least six months after vitrectomy, we measured IOP in both eyes using a rebound tonometer 10 minutes after the patient assumed sitting, supine, right lateral decubitus, and left lateral decubitus positions. Patients with a history of ocular surgery (not including vitrectomy) or recent medication use associated with IOP were excluded. IOP and ocular parameters of vitrectomized and normal fellow eyes were compared. For the decubitus position, IOP values of dependent and nondependent eyes were compared.

Results

No significant difference was observed in IOP between vitrectomized and normal eyes in the sitting and supine positions. The IOP for dependent eyes (on the lower side in the lateral decubitus position) was significantly higher than the IOP for nondependent eyes in both right lateral decubitus (right vitrectomized eye 19.31 ± 4.20 vs. 16.71 ± 4.02 mmHg, p < 0.001; left vitrectomized eye 18.35 ± 1.75 vs. 16.04 ± 3.02 mmHg, p = 0.003) and left lateral decubitus (right vitrectomized eye 17.32 ± 4.63 vs. 19.15 ± 3.83 mmHg, p = 0.004; left vitrectomized eye 16.19 ± 1.81 vs. 18.12 ± 2.29 mmHg, p < 0.001) positions.

Conclusions

IOP was higher in the dependent than the nondependent eye in the lateral decubitus position, for both vitrectomized and nonoperated eyes.

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.

Metabolic characterization of human aqueous humor in the cataract progression after pars plana vitrectomy

BACKGROUND

While pars plana vitrectomy (PPV) has become the third most commonly performed surgery in the world, it can also induce multiple post complications easily. Among them, cataract progression is the most frequent one that can lead to blindness eventually.

METHODS

To understand the underlying mechanisms of post PPV cataract progression, we performed comprehensive metabolic characterization of aqueous humor (AH) samples from 20 cataract patients (10 post PPV complication and 10 none PPV cataract) by a non-targeted metabolomic analysis using gas chromatography combined with time-of-flight mass spectrometer (GC/TOF MS).

RESULTS

A total of 263 metabolites were identified and eight of them are determined to be significantly different (VIP ≥ 1 and p ≤ 0.05) between post PPV group and none PPV control group. The significantly changed metabolites included glutaric acid and pelargonic acid that play key roles in the regulation of oxidative stress and inflammatory responses. Furthermore, we constructed a metabolic regulatory network in each group based on metabolite-metabolite correlations, which reveals key metabolic pathways and regulatory elements including amino acids and lipids metabolisms that are related to cataract progression.

CONCLUSIONS

Altogether, this work discovered some potential metabolite biomarkers for post PPV cataract diagnostics, as well as casted some novel insights into the underlying mechanisms of cataract progression after PPV.

Postoperative Complications of Pars Plana Vitrectomy for Diabetic Retinal Disease

Despite recent advances in the medical management of diabetic retinal disease, there remain established indications for vitreoretinal surgery in the treatment of severe proliferative diabetic retinopathy. These include non-clearing vitreous hemorrhage and tractional retinal detachment. Advances in surgical instrumentation, technique, and experience have led to improved visual outcomes, as well as a corresponding decrease in the incidence of postoperative complications. However, the presence of systemic and ocular factors in diabetic patients increases the risk of adverse events compared to non-diabetic individuals. This review will focus on the most important postoperative complications following pars plana vitrectomy, with specific considerations for the diabetic patient.

Intraocular pressure 1 year after vitrectomy in eyes without a history of glaucoma or ocular hypertension

Objective

The aim of this study was to investigate the incidence, risk factors, and treatment of elevated intraocular pressure (IOP) 1 year after vitrectomy in eyes without a history of glaucoma or ocular hypertension.

Patients and methods

This retrospective study comprised 256 eyes from 256 consecutive patients without a history of glaucoma or ocular hypertension who underwent vitrectomy and were followed up for 1 year. The incidence of elevated IOP at 1 year after vitrectomy was calculated. We compared the characteristics of patients with or without elevated IOP to identify possible risk factors for elevated IOP. The treatments used to control IOP were recorded and analyzed.

Results

A total of 50 patients (19.5%) had elevated IOP after vitrectomy at the 1-year follow-up. Tamponade was a significant risk factor for elevated IOP (P<0.05). The cumulative rates of elevated IOP in eyes with air, balanced salt solution, sulfur hexafluoride, perfluoropropane (C3F8), and silicone oil as the tamponade were 0, 10.8%, 5.9%, 19.8%, and 28.4%, respectively (P<0.05). About 68% of cases of elevated IOP occurred within 1 month after vitrectomy. At 1 year after vitrectomy, 29 patients (58.0%) had stopped their IOP-lowering drugs and 21 (42.0%) patients were continuing these drugs. About 65% of ocular hypertension patients who received silicone oil tamponade had not stopped IOP-lowering drugs; this rate was significantly greater than that of ocular hypertension patients who received C3F8 tamponade (18.2%, P<0.05).

Conclusion

Elevated IOP is a common complication after vitrectomy. Silicone oil tamponade was associated with greater risk of elevated IOP and had long-term effects on IOP. Drugs and surgery were used to control IOP, and some patients required long-term IOP-lowering therapy.

LONG-TERM INTRAOCULAR PRESSURE AFTER UNCOMPLICATED PARS PLANA VITRECTOMY FOR IDIOPATHIC EPIRETINAL MEMBRANE

PURPOSE

To investigate long-term intraocular pressure trends after uncomplicated pars plana vitrectomy for idiopathic epiretinal membrane.

METHODS

Three hundred and sixty-eight eyes of 368 consecutive patients were enrolled. Changes in intraocular pressure 1, 3, 6, and 12 months after surgery and during the final follow-up visit were evaluated in vitrectomized eyes and nonvitrectomized fellow eyes.

RESULTS

The median follow-up period was 36 months (range 12-92 months). Longitudinal data analysis evidenced a 2.5-mmHg (2.2 mmHg; 2.7 mmHg, 95% confidence interval) statistically significant difference in intraocular pressure 30 days after surgery between treated and fellow untreated eyes, gradually recovering to a not significant 0.2-mmHg (-0.1 mmHg; 0.4 mmHg, 95% confidence interval) difference within 26 months. The incidence of late-onset ocular hypertension was 5.7% (21 over 347, 2%; 12%, 95% confidence interval) without difference between the treated eyes and the group control. No significant difference in the incidence of late-onset ocular hypertension and sex, lens status, or gauge of vitrectomy instruments was detected. Only patient's age was significantly higher (mean difference 4.2 years; 0.1-8.0 years, Monte Carlo, 95% confidence interval) in those who developed late-onset ocular hypertension in the vitrectomized eye.

CONCLUSION

Uncomplicated pars plana vitrectomy for idiopathic epiretinal membrane seems not to increase the risk of late-onset ocular hypertension or open-angle glaucoma development.

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.

Risk of Ocular Hypertension in Adults with Noninfectious Uveitis

PURPOSE

To describe the risk and risk factors for ocular hypertension (OHT) in adults with noninfectious uveitis.

DESIGN

Retrospective, multicenter, cohort study.

PARTICIPANTS

Patients aged ≥18 years with noninfectious uveitis seen between 1979 and 2007 at 5 tertiary uveitis clinics.

METHODS

Demographic, ocular, and treatment data were extracted from medical records of uveitis cases.

MAIN OUTCOME MEASURES

Prevalent and incident OHT with intraocular pressures (IOPs) of ≥21 mmHg, ≥30 mmHg, and increase of ≥10 mmHg from documented IOP recordings (or use of treatment for OHT).

RESULTS

Among 5270 uveitic eyes of 3308 patients followed for OHT, the mean annual incidence rates for OHT ≥21 mmHg and OHT ≥30 mmHg are 14.4% (95% confidence interval [CI], 13.4-15.5) and 5.1% (95% CI, 4.7-5.6) per year, respectively. Statistically significant risk factors for incident OHT ≥30 mmHg included systemic hypertension (adjusted hazard ratio [aHR], 1.29); worse presenting visual acuity (≤20/200 vs. ≥20/40, aHR, 1.47); pars plana vitrectomy (aHR, 1.87); history of OHT in the other eye: IOP ≥21 mmHg (aHR, 2.68), ≥30 mmHg (aHR, 4.86) and prior/current use of IOP-lowering drops or surgery in the other eye (aHR, 4.17); anterior chamber cells: 1+ (aHR, 1.43) and ≥2+ (aHR, 1.59) vs. none; epiretinal membrane (aHR, 1.25); peripheral anterior synechiae (aHR, 1.81); current use of prednisone >7.5 mg/day (aHR, 1.86); periocular corticosteroids in the last 3 months (aHR, 2.23); current topical corticosteroid use [≥8×/day vs. none] (aHR, 2.58); and prior use of fluocinolone acetonide implants (aHR, 9.75). Bilateral uveitis (aHR, 0.69) and previous hypotony (aHR, 0.43) were associated with statistically significantly lower risk of OHT.

CONCLUSIONS

Ocular hypertension is sufficiently common in eyes treated for uveitis that surveillance for OHT is essential at all visits for all cases. Patients with 1 or more of the several risk factors identified are at particularly high risk and must be carefully managed. Modifiable risk factors, such as use of corticosteroids, suggest opportunities to reduce OHT risk within the constraints of the overriding need to control the primary ocular inflammatory disease.

Surgically induced changes in retinal vessel diameter, retinal nerve fibre layer thickness, and the optic disc after 23-gauge pars plana vitrectomy

The aim of the study is to investigate the retinal vascular calibre, retinal nerve fibre layer's thickness, and optic disc changes in patients after pars plana vitrectomy. We examined 40 eyes in 40 patients who had undergone unilateral pars plana vitrectomy at three time points: prior to surgery, and at 3 and 6 months after the operation. The diameters of central retinal arteries and veins were measured using retinal photographs. The central retinal arteriolar equivalent (CRAE) and central retinal venular equivalent (CRVE) were calculated using the revised Parr-Hubbard formula. Retinal nerve fibre layer thickness was obtained using Stratus optical coherence tomography. The cup-to-disc vertical ratio of the optic disc was evaluated using stereo optic disc photography. There were no significant differences between the eyes of individual patients before the operation. Cup-to-disc vertical ratios of the optic disc were significantly increased 3 and 6 months postoperatively (p < 0.01, p < 0.01), and there was a significant difference between the operative eye and fellow eye at the same time points (p < 0.01, p < 0.01). Changes in CRAE and CRVE in the operative eyes were significantly larger than the fellow eyes 6 months postoperatively (p < 0.01, p < 0.01). The retinal nerve fibre layer thickness showed no significant changes. While there were no changes in retinal nerve fibre layer thickness, vitrectomy induced changes in the cup-to-disc vertical ratio of the optic disc and retinal vessel diameter for at least 6 months after surgery.

Long-Term Changes in Intraocular Pressure after Vitrectomy for Rhegmatogenous Retinal Detachment, Epi-Retinal Membrane, or Macular Hole

Purpose

To determine the long-term changes in the intraocular pressure (IOP) following vitrectomy for rhegmatogenous retinal detachment (RRD), epiretinal membrane (ERM), and macular hole (MH), and to investigate the relationship between the retinal disease and the incidence of late-onset IOP elevation.

Methods

This was a retrospective, observational, comparative study. We reviewed the medical records of 54 eyes of 54 RRD patients, 117 eyes of 117 ERM patients, and 75 eyes of 75 MH patients who underwent 20-, 23- or 25-gauge vitrectomy. The IOPs before surgery and 1, 3, 6, and 12 months following vitrectomy, and also at the final visit (average, 23.95 months) were evaluated. We defined a significant increase in the IOP as an increase of ≥4 mmHg from the preoperative IOP, and this increase was taken to be a ‘death’ event for the Kaplan-Meier survival analyses.

Results

The mean follow-up period was not significantly different among the groups. The mean IOP at 3 (P = 0.001) and 12 (P = 0.011) months following the vitrectomy and at the final visit (P = 0.002) were significantly higher than that before the vitrectomy in the RRD group. The mean IOP in the RRD group was significant higher than that in the ERM group at 1 (P = 0.005), 3 (P = 0.009), and 12 (P = 0.013) months following vitrectomy, and at the final visit (P = 0.032). Kaplan-Meier survival analyses showed that the RRD group had a significantly higher risk of an IOP increase following vitrectomy than the other groups (P<0.001 by log-rank test). Multivariate logistic regression analyses showed that a preoperative diagnosis of RRD was the only risk factor that was significantly associated with a postoperative IOP elevation after excluding eyes with a low preoperative IOP (odds ratio, 3.208; P = 0.003).

Conclusions

A late-onset IOP elevation following vitrectomy was observed only in eyes that underwent RRD surgery. The elevation was probably caused by the specific characteristics and surgical procedures of RRD. Clinicians should pay more attention to the IOP elevation for long times after vitrectomy especially in eyes with RRD.

Glaucoma management after vitreoretinal surgeries

PURPOSE OF REVIEW

The surgical management of retinal disorders, including scleral buckling procedures, pars plana vitrectomy, and intravitreal injections of gas or silicone oil, can lead to short-term elevations in intraocular pressure (IOP) and ultimately long-term glaucomatous damage if not treated in a timely manner. Glaucoma in these cases is commonly refractory to conventional therapies. This review highlights the treatment strategies for glaucoma in eyes that have previously undergone vitreoretinal surgery.

RECENT FINDINGS

Although medical therapy is often used initially to control a temporary rise in IOP, laser and surgical therapy may be required to treat sustained IOP elevation and subsequent glaucomatous damage in eyes that have undergone intraocular surgery for retinal disorders. Glaucoma drainage devices are an important treatment modality, particularly when there is high risk of failure with filtering surgery.

SUMMARY

Previous vitreoretinal surgery is a known risk factor for the development of glaucoma. Treatment is usually initiated with medical therapy, however, surgical intervention is frequently required to control IOP and prevent progressive glaucomatous damage in patients with refractory glaucoma.

Glaucoma drainage device surgery after vitreoretinal surgery: incidence and risk factors

PURPOSE

The initial success of vitreoretinal surgery can be annihilated by an acceleration of preexisting glaucoma or the development of secondary glaucoma. Aim of this study was to determine the incidence of and risk factors for medically uncontrollable glaucoma after vitreoretinal surgery.

METHODS

Case-control study amongst patients who underwent vitreoretinal surgery at the University Medical Center Groningen between 1991 and 2011 (in total 14,942 interventions). Cases were all patients who received a glaucoma drainage device after vitreoretinal surgery. Controls were a subset of the patients who underwent vitreoretinal surgery without a subsequent drainage device. Cases and controls were matched (three controls per case) with regard to the year of the (first) vitreoretinal intervention. The incidence rate was calculated from the number of cases and the number of person-years corresponding to all vitreoretinal interventions performed in the study period. Risk factors were analysed with logistic regression.

RESULTS

Ninety-five cases were identified after a follow-up of 101,961 person-years (one per 1000 person-years). Cases were younger (p = 0.017), were more often men (p = 0.035), underwent more interventions (p < 0.001) or were treated with silicone oil (p = 0.021), had a higher intra-ocular pressure 1 week after the intervention (p < 0.001) and had more often a history of glaucoma or ocular hypertension (p < 0.001).

CONCLUSION

Glaucoma after vitreoretinal surgery that requires a glaucoma drainage device is not very common and patients who need a device differ from those who do not. This gives the opportunity to monitor certain subgroups more closely.

[Structural and functional characteristics of vitrectomized eyes]

The article describes the potential effects of vitrectomy on clinical refraction, refraction of the cornea and its biomechanical parameters, the state of the lens, intraocular pressure, and biometric parameters of the anterior eye segment.

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.

The value of preoperative medical testing for vitreoretinal surgery

PURPOSE

To determine whether preoperative medical testing reduces the risk of postoperative systemic adverse events after vitreoretinal surgery.

METHODS

Retrospective cohort study at a single academic university hospital involving a total of 2,215 patients undergoing vitreoretinal surgery. Medical charts of 2,215 patients who underwent vitreoretinal surgery between January 2002 and November 2011 at Vanderbilt University were reviewed for baseline comorbidities, preoperative testing, type of anesthesia during surgery, and systemic adverse events occurring within 30 days after surgery. Main outcome measures were the association of baseline characteristics and preoperative testing with postoperative systemic adverse events.

RESULTS

Approximately a half of patients had electrolyte, renal function, and electrocardiogram evaluation. The most common comorbidities were hypertension (53%), diabetes mellitus (37%), and coronary artery disease (18%). The most common preoperative testing performed was blood glucose (58%). A total of 102 systemic adverse events occurred in 89 of 2,215 patients (4%) within the first 30 days after surgery with the majority (72%) occurring within the first 24 hours. The most common adverse event was bradycardia (34%) followed by desaturation (25%). Patients with a history of coronary artery disease, asthma, chronic renal disease, or receiving general anesthesia had a 2.04 (P = 0.01), 2.18 (P = 0.03), 2.76 (P < 0.01), and 3.72 (P < 0.001) increased odds of developing postoperative systemic adverse events, respectively. Multivariate logistic regression analysis demonstrated no significant correlation between preoperative testing and postoperative adverse events.

CONCLUSION

Incidence of postoperative systemic adverse events after vitreoretinal surgery was 4% and was significantly increased in patients with coronary artery disease, asthma, chronic renal disease, or receiving general anesthesia. In this series, preoperative testing did not measurably influence rates of postoperative systemic complications.

Incidence of late-onset ocular hypertension following uncomplicated pars plana vitrectomy in pseudophakic eyes

PURPOSE

To determine the incidence of late-onset ocular hypertension following uncomplicated vitrectomy in pseudophakic eyes with an open angle.

DESIGN

A retrospective observational case series.

METHODS

Seven hundred and sixty-seven eyes of 767 patients that underwent vitrectomy combined with cataract surgery in 1 eye were studied. There were 383 men and 384 women. The indications for vitrectomy were: 308 eyes with rhegmatogenous retinal detachment, 202 eyes with epiretinal membrane, 169 eyes with macular hole, 44 eyes with vitreous hemorrhage, 16 eyes with subretinal hemorrhage, 15 eyes with vitreomacular traction syndrome, 12 eyes with vitreous opacity, and 1 eye with retinoschisis. Of these, 176 eyes underwent vitrectomy alone because of previous cataract surgery. Late-onset ocular hypertension was defined as an intraocular pressure (IOP) >21 mm Hg that developed more than 2 months postoperatively in at least 2 postoperative visits. An increase in the IOP >4 mm Hg over the preoperative IOP was necessary. Eyes with ocular hypertension, glaucoma (suspect), or a possibility of IOP elevation were excluded.

RESULTS

The mean age was 63 ± 11 years. The mean follow-up duration after vitrectomy was 47.8 ± 25.3 months. Thirty-two eyes (4.2%) developed late-onset ocular hypertension. The mean age was 60 ± 10 years. The mean interval between vitrectomy and development of ocular hypertension was 31.1 ± 26.0 months. There were no significant differences in the incidence of late-onset ocular hypertension and the vitreoretinal disease for vitrectomy, sex, or gauge of instruments for vitrectomy.

CONCLUSION

Long-term IOP monitoring is necessary after vitrectomy.

Prevalence of open angle glaucoma in vitrectomized eyes: a cross-sectional study

PURPOSE

Primarily to assess and compare the prevalence of open-angle glaucoma (OAG) in previously vitrectomized and nonvitrectomized eyes at our institution. Secondarily to assess and compare the prevalence of OAG in eyes those were phakic and pseudophakic/aphakic at the time of vitrectomy.

METHODS

A cross-sectional prevalence study was designed. Patients who underwent pars plana vitrectomy at our institution from January 2006 to December 2011 and had not been diagnosed with OAG before the surgical procedure were contacted by phone. Those patients who agreed to participate were invited to the University Hospital of Ourense (Spain) for a comprehensive ophthalmic assessment, including Perkins tonometry, gonioscopy, examination of the optic disk, and a spectral-domain optical coherence tomography scan of the optic nerve head. The definition of OAG was based on standardized criteria, modified versions of the Rotterdam Study, and those published by Foster et al.

RESULTS

Among 472 eligible patients, 182 responded and agreed to participate in our study. Of these, 26 were excluded. Finally, 312 eyes of 156 patients were included in the analysis. Fifteen vitrectomized (8.9%) and 3 nonvitrectomized (2%) eyes were diagnosed with OAG. This difference was statistically significant (P = 0.02, chi-square test). Differences in the prevalence of OAG between eyes those were phakic and pseudophakic/aphakic at the time of vitrectomy were not statistically significant (P = 0.48, chi-square test).

CONCLUSION

Our study supports the hypothesis of an increased risk of OAG after vitrectomy. Prevalence of OAG in vitrectomized eyes was significantly higher compared with nonvitrectomized ones. However, we were not able to demonstrate significant difference in the prevalence of OAG between eyes those were phakic or aphakic/pseudophakic at the time of vitrectomy.

Long-term trends in intraocular pressure after combined vitrectomy with sub-tenon injection of triamcinolone acetonide

PURPOSE

To evaluate the long-term effect of vitrectomy by itself and combined vitrectomy with sub-Tenon injection of triamcinolone acetonide (TA) on intraocular pressure (IOP).

METHODS

In a retrospective cohort study, the medical records of 56 eyes of 56 patients who underwent nonemergent vitrectomy and were followed up for at least 24 months were reviewed. Thirty-two eyes of 32 patients underwent combined vitrectomy with sub-Tenon injection of TA. Twenty-four eyes of 24 patients underwent vitrectomy only. Increased IOP of >4 mmHg from the baseline, change in IOP from the baseline, and preoperative and postoperative measured IOPs were recorded and compared between the two groups, and with fellow eyes.

RESULTS

Minimum follow-up period was 24 months. Except the IOP at postoperative 1 day, there were no significant differences between vitrectomized eyes and nonvitrectomized fellow eyes. There were also no differences between vitrectomized eyes and eyes that underwent combined vitrectomy with sub-Tenon injection of TA. And in the comparison of the vitrectomy-only eye group and the vitrectomy with sub-Tenon TA eye group, there was also no significant difference during the whole follow-up period.

CONCLUSION

Vitrectomy by itself or combined vitrectomy with sub-Tenon injection of TA does not seem to increase IOP in the long term.

Microincision vitrectomy surgery in vitreomacular traction syndrome of retinitis pigmentosa patients

Purpose. To investigate long-term retinal changes after microincision pars plana vitrectomy surgery (MIVS) and internal limiting membrane (ILM) peeling outcome in retinitis pigmentosa (RP) patients affected by vitreomacular traction syndrome (VMT) with higher vitreous surface adhesion or coexisting epiretinal membrane (ERM). Methods. Eight RP patients suffering from VMT were evaluated by means of best corrected visual acuity (BCVA), anterior and posterior binocular examination, spectral-domain optical coherence tomography (SD-OCT), MP-1 microperimetry (MP-1), and full-field electroretinogram (ERG), before MIVS and ILM peeling and during the 36-month follow-up. Patients were hospitalized for two days after the surgery. Surgical procedure was performed following this schedule: surgical removal of crystalline lens (MICS), MIVS with 23-gauge sutureless system trocars, core vitreous body removal, and balanced-sterile-salin-solution- (BSS-) air-gas (SF₆) exchange. Results. All patients presented visual acuity (VA) increase after MIVS. None of the patients developed ocular hypertension or vitreomacular adhesions during the 3-year follow-up. MP-1 bivariate contour ellipse area (BCEA) was reduced in its dimensions and improved in all patients demonstrating a better fixation. Conclusions. MIVS could be the gold standard therapy in RP patients with VMT and higher vitreous surface adhesion or coexisting ERM if medical therapy is not applicable or not effective.

Long-term intraocular pressure changes after vitrectomy for epiretinal membrane and macular hole

Background

To investigate long-term intraocular pressure (IOP) changes after vitrectomy for epiretinal membrane (ERM) or macular hole (MH).

Methods

We retrospectively reviewed the medical records of 57 eyes with ERM and 61 eyes with MH that underwent vitrectomy. IOP levels and changes at 1, 3, 6, 12 months, and the final visit from baseline were evaluated in vitrectomized eyes and non-vitrectomized fellow eyes.

Results

In the ERM group, the mean follow-up period was 29.3 months; the mean preoperative IOP in the operated eyes was 12.9 ± 2.5 mmHg and the final IOP was 13.2 ± 2.9 mmHg. In the MH group, the mean follow-up period was 25.6 months; the mean preoperative IOP in the operated eyes was 13.3 ± 2.5 mmHg and the final IOP was 14.0 ± 3.2 mmHg. The mean final IOP of the fellow unoperated eyes was 13.0 ± 2.5 mmHg in the ERM group and it was 12.9 ± 3.2 mmHg in the MH group. A significant difference was found between the operated eyes and fellow eyes at the final visit in the MH group (P < 0.01) but not in the ERM group (P = 0.40). MH group was significantly at high risk of IOP increase after vitrectomy (P < 0.01).

Conclusions

IOP increase after vitrectomy was found in some eyes with MH during long-term follow-up but it was unlikely in eyes with ERM.

Prospective Retinal and Optic Nerve Vitrectomy Evaluation (PROVE) study: findings at 3 months

Background

The purpose of this paper is to report the 3-month findings of the Prospective Retinal and Optic Nerve Vitrectomy Evaluation (PROVE) study.

Methods

Eighty eyes of 40 participants undergoing vitrectomy were enrolled. Participants underwent baseline evaluation of the study (surgical) and fellow (control) eye that included: intraocular pressure, central corneal thickness, gonioscopy, cup-to-disc ratio measurement, color fundus and optic disc photography, automated perimetry, and optical coherence tomography of the macula and optic nerve. Evaluation was repeated at 3 months. Main outcome measures were changes in macula and retinal nerve fiber layer (RNFL) thickness and intraocular pressure.

Results

All participants completed follow-up. Mean cup-to-disc ratio of study and fellow eyes at baseline was 0.43 ± 0.2 and 0.46 ± 0.2, respectively, and 13% of participants had undiagnosed narrow angles. There was no significant change in intraocular pressure, cup-to-disc ratio, or pattern standard deviation in study eyes compared with baseline or fellow eyes at 3 months. Vision improved in all study eyes at 3 months compared with baseline (P = 0.013), but remained significantly worse than fellow eyes (P < 0.001). Central subfield and temporal peripapillary RNFL thickness were significantly greater in eyes with epiretinal membrane (P < 0.05), and resolution after surgery correlated with visual improvement (P < 0.05).

Conclusion

The 3-month results do not indicate any increased risk for open-angle glaucoma but suggest that a relatively high percentage of eyes may be at risk of angle closure glaucoma. Temporal RNFL thickness and central subfield were increased in eyes with epiretinal membrane, and resolution correlated with degree of visual recovery.

Long-term intraocular pressure changes after combined phacoemulsification, intraocular lens implantation, and vitrectomy

PURPOSE

To observe long-term changes in intraocular pressure (IOP) after a combined phacoemulsification, intraocular lens implantation, and vitrectomy procedure.

METHODS

This was a retrospective case series at a single hospital. Of 105 consecutive cases that received combined phacoemulsification, intraocular lens implantation, and vitrectomy for macular hole or epiretinal membrane, 85 eyes (patients) were followed up for 1 year or longer. The IOP of both eyes in the subjects who had surgery in one eye was measured at baseline and at 1, 3, 6, 12, 24, 36, 48, and 60 months postoperatively. The IOP of the treated eye was compared with the fellow eye and with the baseline value at each follow-up visit.

RESULTS

Intraocular pressure in the operated eyes at 3 months after surgery was significantly lower than that at baseline and than that in the respectively fellow eyes (P < 0.001, paired-t test with Bonferroni correction). The IOP subsequently returned to the baseline value or was the same as that of the fellow eye within 3 months of the observation time point. Only two treated eyes had elevated IOP exceeding 21 mmHg after 6 months postoperatively.

CONCLUSIONS

The change in the IOP after phacovitrectomy may be limited, and care when using this procedure because some eyes show increased IOP compared to the fellow eye after a long period.