Positive vitreous pressure: Pathophysiology, complications, prevention, and management

Complications After Pediatric Penetrating Keratoplasty: An IRIS Registry Study

PURPOSE

To describe the frequency of postoperative complications in children undergoing penetrating keratoplasty (PK).

METHODS

This retrospective cohort study included pediatric patients (aged 0-18 years) in the Intelligent Research in Sight (IRIS) Registry who underwent primary PK between January 2013 and December 2020. Patients were identified using Current Procedure Terminology codes. Postoperative complications were identified using International Classification of Diseases Revision 9 and 10 codes and categorized as complications affecting the anterior segment (epithelial defect, infectious keratitis, neurotrophic keratitis, and glaucoma) or posterior segment (vitreous hemorrhage, retinal detachment, choroid detachment, choroidal hemorrhage, endophthalmitis, epiretinal membrane, and proliferative vitreoretinopathy).

RESULTS

Of the 544 pediatric patients undergoing PK, 259 (47.6%) experienced postoperative complications. Anterior segment complications (n = 222, 40.8%) were more common than posterior segment complications (n = 96, 17.6%). The most common anterior complication was infectious keratitis (n = 163, 30.0%) with a median onset time of 275 days (IQR 50-560 days) after surgery. Vitreous hemorrhage (n = 52, 9.6%) and retinal detachment (n = 48, 8.8%) were the most common posterior segment complications.

CONCLUSIONS

Infectious keratitis was the most common postoperative complication in children undergoing PK. More complications occurred in the anterior segment (70%) of the eye as compared with the posterior segment (30%). These findings demonstrate the challenges associated with pediatric PK and may help guide postoperative monitoring and management.

Refractive Lens Exchange: A Review

In recent decades, technical advancements in lens surgery have considerably improved safety and refractive outcomes. This has led to a much broader range of indications for refractive lens exchange (RLE). Effective restoration of uncorrected distance and near visual acuity is possible with modern presbyopia correcting intraocular lenses (IOLs). Hyperopic patients who are fully presbyopic were identified as ideal candidates for RLE. For myopic patients, an increased risk of retinal detachment has been reported, which leads to a higher threshold to perform RLE in this patient group. The most frequent postoperative complications include posterior capsular opacification, deviation from the target refraction and cystoid macular edema. Thus, adequate planning of surgery, careful patient selection, as well as comprehensive counseling are crucial for successful RLE.

Temporary Pupil Scaffolding Technique for Managing Positive Vitreous Pressure and Impending IOL and Vitreous Extrusion During Penetrating Keratoplasty

PURPOSE

Positive vitreous pressure (PVP) secondary to intraoperative acute hypotony during penetrating keratoplasty can result in extrusion of the intraocular lens and vitreous. Currently described techniques are difficult or impossible to apply intraoperatively when positive vitreous pressure is noticed in an "open sky" situation after excision of the host corneal button.

METHODS

We describe a technique where pupil scaffolding is used to prevent intraocular lens or crystalline lens extrusion by simply closing the pupil with a temporary suture that holds the retropupillary contents back. Once the eye is thus stabilized, the donor cornea is sutured rapidly after which the pupillary knot is cut and removed using microscissors and microforceps.

RESULTS

Five patients undergoing penetrating keratoplasty under peribulbar anesthesia underwent this technique after experiencing PVP after host corneal button excision. PVP was successfully controlled in all 5 patients, and the optical grafts remained clear in the postoperative period.

CONCLUSIONS

Temporary pupillary scaffolding can help control PVP and prevent ocular content extrusion during PKP surgeries.

Descemet Membrane Endothelial Keratoplasty (DMEK) Anesthesia Analysis

PURPOSE

Comparison of safety and clinical results of Descemet membrane endothelial keratoplasty (DMEK) in topical, peribulbar, or general anesthesia.

METHODS

Retrospective, post hoc matched study of 346 patients who received DMEK surgery with different types of anesthesia (n = 54 topical, n = 137 peribulbar, n = 155 general anesthesia). Outcome criteria were intraoperative complications, endothelial cell count (ECC), central corneal thickness (CCT) and graft rejection rate, rebubbling rate, and visual acuity (VA). Mean follow-up time was 9.4 ± 2.8 months.

RESULTS

The group with topical anesthesia showed intraoperative difficulties such as vitreous pressure (p = 0.01) and difficult graft unfolding (p = 0.4), possibly leading to a higher rebubbling rate (p = 0.03) and therefore graft failure (p = 0.39). However, rebubbling and graft failure occurred more often when the graft preparation was more difficult (p = 0.2, p = 0.13, respectively), which was independent of anesthesia. All three groups achieved comparable functional results regarding VA, ECC, and CCT after 6 months.

CONCLUSION

DMEK under topical anesthesia is feasible and shows comparable final visual outcomes but should be limited to selected cooperative patients and performed by experienced surgeons due to the potential for increased intraoperative challenges.

The use of sub-Tenon's anesthesia versus a low-dose neuromuscular blockade for canine cataract surgery: A comparative study of 224 eyes

OBJECTIVE

Assess the utility of a Sub-Tenon's anesthesia (STA) protocol to provide suitable operating conditions for canine cataract surgery and compare it to an alternative low-dose neuromuscular blockade (LD-NMB) protocol used for canine cataract surgery.

PROCEDURES

Clinical study of dog eyes undergoing cataract surgery with either an STA or LD-NMB protocol. While intraoperative vitreal expansion scores and intraoperative complications were collected prospectively, globe position, intraocular pressure, return of vision, and postoperative complications were collected retrospectively. Statistical testing was used to compare results between the STA and the LD-NMB groups for the data available.

RESULTS

A total of 224 eyes from 126 dogs were assessed, with 133/224 (59.4%) eyes from 99/126 (78.6%) dogs receiving STA and 91/124 (40.6%) eyes from 72/126 (57.1%) dogs receiving LD-NMB. Forty-five of these dogs (45/126; 37.7%) received STA for one eye and LD-NMB for the other eye. There was no significant change in intraocular pressure measurements following STA administration. This was not measured for the LD-NMB group. The globe achieved a central position in 110/133 (82.7%) of eyes that received STA. This was not measured for the LD-NMB group. Intraoperative vitreal expansion scores were slightly higher in STA-treated eyes compared to LD-NMB-treated eyes. The intraoperative complication rate for STA-treated eyes was higher (73/133; 54.8%) compared to NMB-treated eyes (12/91; 13.2%). The most common intraoperative complication for STA was chemosis (64/133; 48.1%), the risk of which increased with an increase in the volume of local anesthetic injected. The post-operative complication rate was higher in STA-treated eyes (28/133; 21.1%) compared to NMB-treated eyes (16/91; 17.6%). Post-operative corneal ulceration was the most common postoperative complication in STA-treated eyes (6/133; 4.5%).

CONCLUSION

The STA protocol described resulted in suitable operating conditions, but more intraoperative and postoperative complications compared to the LD-NMB protocol. Despite these complications, the STA protocol did not cause a significant deleterious impact on post-operative outcomes as defined in the present study.

Deep Anterior Lamellar Keratoplasty Over Penetrating Keratoplasty to Mitigate Positive Vitreous Pressure Complications

This report describes deep anterior lamellar keratoplasty over penetrating keratoplasty (DALK-over-PKP) as an alternative technique to mitigate complications related to positive vitreous pressure (PVP) during PKP. We accomplished this by repairing the punctured cornea and performing a modified DALK where a full-thickness donor graft is placed over the host Descemet membrane, which is then removed after partial suturing of the graft. This mitigates the driving force behind the PVP by maintaining a closed-anterior chamber.

Indications and Results of Emergency Penetrating Keratoplasty With Simultaneous Cataract Surgery ("Triple-PKP à Chaud")

PURPOSE

The purpose of this study was to analyze the indications and clinical results of emergency penetrating keratoplasty with simultaneous cataract surgery ("Triple-PKP à chaud").

METHODS

This study included all subjects who underwent Triple-PKP à chaud between 2006 and 2020 at the Department of Ophthalmology, Saarland University Medical Center, Homburg/Saar in Germany. Data obtained from patient records were retrospectively analyzed.

RESULTS

Triple-PKP à chaud was successfully performed in 27 of 29 eyes with a mean age of 66.0 ± 19.9 years. Previous surgery was performed in 20 eyes (69.0%), most frequently amniotic membrane transplantation in 11 eyes (37.9%) and previous keratoplasty in 9 eyes (31.0%). The most common indication was infectious keratitis (62.1%). In 27 subjects (93.1%), capsulorhexis was performed using the open-sky technique. The most frequent intraoperative complication was positive vitreous pressure (24.1%). In 2 eyes (6.9%), no intraocular lens implantation was performed because of posterior capsule rupture. The preoperative uncorrected visual acuity improved from 2.2 ± 0.6 logMAR (range = 3.0-0.7 logMAR) to 1.3 ± 0.7 logMAR (range = 3.0-0.18 logMAR) postoperatively ( P < 0.001). Common postoperative complications were suture loosening (44.4%) and corneal epithelial defects (33.3%). Repeat keratoplasty was necessary in 14 eyes (51.9%), including 9 eyes (64.2%) within 12 months postoperatively. The mean graft survival was 12.2 ± 17.9 months (range = 1-69 mo).

CONCLUSIONS

Triple-PKP is also feasible in emergency conditions. Nevertheless, the surgery is associated with an increased risk of intraoperative and postoperative complications. Combined surgery should, therefore, only be performed in severely diseased eyes with progressed stage of cataract.

Incidence, Pathophysiology, Complications, and Management of Positive Vitreous Pressure During Penetrating Keratoplasty: A Literature Review

Positive vitreous pressure (PVP) is common during open anterior segment surgery and penetrating keratoplasty (PKP) has a reported incidence rate of 40-50%. Despite adequate perioperative preventive precautions, positive pressure occurs during surgery and optimum management of PVP is required to avoid serious complications. Many pharmacological and mechanical approaches can be employed either preoperatively or intraoperatively to decrease vitreous pressure. Surgical techniques such as graft-over-host technique, the modified graft-over-host technique, techniques employed mattress sutures and needle, or Vitreous aspiration or vitrectomy can be effectively used to manage intraoperative PVP during PPK. This article reviews the incidence, risk factors, prevention, and different approaches to the management of positive vitreous pressure during PKP to analyze the available evidence in order to improve the safety profile of PKP and prevent sight-threatening complications.

Needle aspiration for management of acute intraoperative fluid misdirection during phacoemulsification

Purpose

Acute intraoperative fluid misdirection is a serious complication that may occur during phacoemulsification. We provide a detailed description and a video of our preferred technique for prompt management of acute intraoperative fluid misdirection.

Observations

A 79-year-old male developed sudden shallowing of the anterior chamber and marked elevation of intraocular pressure at hydrodissection during phacoemulsification surgery. Treatment consisted of a needle aspiration of trapped fluid from the retrolental space, employing a 5/8th inch, 25-gauge needle on a medium-size syringe leading to immediate softening of the globe and deepening of the anterior chamber. The rest of the case proceeded uneventfully. The patient had uncomplicated recovery and final best-corrected visual acuity of 20/20.

Conclusions and importance

Acute subcapsular infusion fluid entrapment may occur during uneventful phacoemulsification. Needle aspiration of retrolental fluid is a simple and inexpensive method for immediate resolution of high IOP and deepening of the anterior chamber, allowing the case to proceed.

Surgical correction of corneal opacity and aniridia with penetrating keratoplasty and a new iris prosthesis implant

PURPOSE

This study is to describe the clinical outcome of penetrating keratoplasty combined with implantation of a novel intraocular lens with an artificial iris, aided by continuous vitreous chamber infusion, in patients with severe aniridia and corneal alterations.

METHODS

This was a prospective single-center case series study involving five patients with corneal alterations and aniridia. All subjects underwent simultaneous penetrating keratoplasty and implantation of a new intraocular lens with an artificial iris with the assistance of infusion into the vitreous chamber to regulate intraocular pressure during the surgical procedure. Visual acuity, corneal endothelial cell density, and intraocular pressure assessments were performed in the postoperative period. The final cosmetic outcome of the iris prosthesis placement was also evaluated.

RESULTS

In all cases, increased visual acuity and a good aesthetic result were observed in all affected eyes except one in which, despite the excellent aesthetic outcome, the eye was very hypotonic as it had high myopia and had undergone several previous surgeries.

CONCLUSION

The single surgical procedure combining implantation of an intraocular lens-iris prosthesis with penetrating keratoplasty is an effective technique for the simultaneous treatment of aphakia and aniridia. However, larger series with longer-term follow-up are needed to definitively establish the benefits of this technique.

Clinical features, management and outcomes of expulsive choroidal hemorrhage during cataract surgery: 13 years experience from a tertiary eye center

PURPOSE

To study the risk factors, clinical features, management, and outcomes of intraoperative expulsive choroidal hemorrhage (ECH) during cataract surgery.

SETTING

Aravind eye hospital, Madurai, Tamil Nadu, India.

DESIGN

Retrospective hospital-based study.

METHODS

Of the 1167250 patients who underwent cataract surgery between 2008 to 2020, patients diagnosed with intraoperative ECH were included. Demography, ocular and systemic risk factors, visual acuity, type of ocular anesthesia, intraoperative and postoperative records, management, and surgical outcomes were analyzed.

RESULTS

A total of 52 eyes (0.004%) of 1167250 patients had ECH. Of the 52 cases, 43 cases (incidence rate 0.006%) were reported in the years 2008 to 2015 and 9 cases (incidence rate 0.002%) in the years 2016 to 2020. The change in the ocular anesthesia from peribulbar and retrobulbar anesthesia (2008-2015) to sub-Tenon's anesthesia (2016-2020) was associated with a reduced rate of ECH (p-value 0.002). Twenty-eight eyes (53.8%) were having limited ECH and 24 eyes (46.2%) were having full-blown ECH. The visual outcome was better in eyes with limited ECH compared to full-blown SCH in all follow-up visits. The median vision (IQR) before the cataract surgery and immediate postoperative day 1 were 1.30 (0.78 - 2.60) and 2.45 (1 - 2.75) respectively. The median final vision (IQR) after the secondary surgical intervention was 2.2 (0.60 - 2.60).

CONCLUSIONS

This series included 52 eyes with ECH, recognized associations of ECH with different types of anaesthesia as well as with different cataract surgical procedures, and described management of ECH. Postoperative visual outcome was poor.

Intra-operative control of positive vitreous pressure in a graded manner by pars plana sutureless, small gauge trocar-cannula

BACKGROUND

The purpose of this paper is to delineate a technique of using a 23G, single, sutureless transconjunctival pars plana sclerotomy to facilitate anterior segment surgery in eyes with increased positive vitreous pressure (PVP) ascribe to predisposing or intraoperative factors.

METHODS

We have implemented this technique in five eyes when PVP was anticipated before the surgery because of risk factors or it was encountered during anterior segment surgery. Different case scenarios in which PVP occurs during the surgery comprising phacolytic glaucoma, corneal tear repair combined with cataract surgery with IOL in a case with traumatic corneal injury, anterior capsule rupture and secondary glaucoma, Trabeculectomy in case of uveitic glaucoma, routine phacoemulsification cataract surgery with PVP encountered during surgery were addressed by using this technique.

RESULTS

The new technique outlined by the authors consists of passing sutureless 23 G trocar cannula which enables controlled and gradual efflux of clear watery fluid, resulting in passive vitreous decompression with minimal risk of vitreous traction and retinal breaks. Once PVP is reduced, anterior segment surgery can be safely completed without risk of developing devastating complications.

CONCLUSIONS

This sutureless single port pars plana trocar cannula technique is minimally invasive, safe, effective and fast technique which can cause reduction of PVP intraoperatively in a controlled and graded manner, thereby minimizing complication rates in difficult case scenarios.

"Basket" mattress suture to manage positive vitreous pressure during penetrating keratoplasty

OBJECTIVE

To describe a new/modified technique to manage posterior vitreous pressure (PVP) during penetrating keratoplasty (PKP) and report a small series.

DESIGN

Retrospective interventional case series and technique description.

PARTICIPANTS

PKP eyes necessitating mattress suture placement owing to PVP.

METHODS

Retrospective chart review from 2016 to 2019 was undertaken. Placed prophylactically (before trephination) or after trephination, the mattress suture is placed limbus-to-limbus across the anterior chamber. A second mattress suture can be placed in the opposite meridian (perpendicularly) for added support (safety basket configuration). Variations of suture technique are described based on lens status (i.e., phakic, pseudophakic, aphakic) and intraoperative timing. Parameters assessed included demographics, lens status, suture indications, intraoperative technique details, successful PKP completion, and presence of primary failure.

RESULTS

There were 6 phakic eyes (5 patients) and 9 pseudophakic/aphakic eyes (8 patients). Indications for the phakic subgroup were obesity (83%), poor scleral rigidity (83%), repeated iris prolapse (67%), dense mature cataract (33%), and planned large-diameter PKP (33%). Indications for pseudophakic/aphakic eyes included intraocular lens/iris prolapse (100%), pre-existing iris defects (67%), and planned large-diameter PKP (33%). Successful PKP was performed in all cases. Whereas one case had residual corneal edema in the setting of a persistent epithelial defect owing to limbal stem cell deficiency, all other cases demonstrated no primary graft failure.

CONCLUSIONS

Although increased PVP can present a stressful and challenging situation, it is important to have multiple options for management. This simple mattress suture technique normalizes the lens-iris complex behaviour and appears safe for the donor graft.

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.

Stepwise Decreasing of Vitreous Pressure by Anterior Vitrectomy: A Novel Method for Preventing Positive Vitreous Pressure During Penetrating Keratoplasty

BACKGROUND

This study evaluates the clinical effects of the stepwise anterior vitrectomy on the prevention of positive vitreous pressure (PVP) during penetrating keratoplasty (PKP).

METHODS

PKP in conjunction with stepwise anterior vitrectomy was performed on 15 eyes of 15 patients under retrobulbar anesthesia. A preset vitrectomy trocar-cannula was inserted into the vitreous cavity before PKP. During the opening of the anterior chamber, intermittent vitrectomy and corneal incision expansion were performed alternately to keep the lens or artificial intraocular lens (IOL) and iris flat until the entirety of the pathological cornea had been dissected. The main outcome measures include visual acuity, crystalline lens rise (CLR), corneal curvature and diopter, and corneal endothelial cell loss.

RESULTS

All surgical procedures were performed successfully without any PVP-related intraoperative complications. The mean time of the stepwise vitrectomies was 3.1 ± 0.7 s, the duration of each vitrectomy was 8.1 ± 5.3 s, and the duration of the total surgery was 60.5 ± 5.3 min. The anterior segment reaction was mild and the shape of the pupil remained normal 1 day after surgery. The mean preoperative and mean 3-month postoperative CLR values were 0.48 ± 0.09 mm and - 0.16 ± 0.04 mm, respectively (p < 0.0001). The mean preoperative endothelial cell density in donor buttons was 2570 ± 171 cells/mm², and the mean 6- and 12-month postoperative endothelial cell density in donor buttons was 2207 ± 127 cells/mm² and 2000 ± 198 cells/mm², respectively.

CONCLUSIONS

The novel and stabilized PKP procedure, performed in conjunction with the stepwise anterior vitrectomy, effectively avoided the PVP during open-sky surgery.

TRIAL REGISTRATION

Chinese Clinical Trial Registry, ChiCTR1900021227.

New use of a pupillary expansion ring to avoid intraoperative positive vitreous pressure during triple procedures

Positive vitreous pressure can complicate cataract surgery during a triple procedure by inadvertently extending the capsulorhexis. This occurs because the procedure is open sky and positive vitreous pressure cannot be countered by injecting ophthalmic viscosurgical devices. We describe a new use of a pupillary expansion ring (Malyugin) to achieve a stable open anterior chamber under open sky during triple procedures. The scrolls are tucked under cut margins of the host cornea to create the capsulorhexis, the cataractous nucleus is removed, and an intraocular lens (IOL) is implanted in the bag. This technique is especially useful in cases of hypermature cataract and nondilating pupils with positive vitreous pressure in patients having triple procedures. The technique provides a stable open anterior chamber, increasing to the safety of the procedure and the chance of achieving a continuous curvilinear capsulorhexis and IOL implantation in the capsular bag.

Avoiding Complications From Patient Positioning for Intraocular Surgery

Collaboration of the surgical and anesthesia teams for patient positioning is essential to assure patient comfort and safety, preventing systemic and ophthalmic complications. The goals and rationales of positioning for intraocular surgery are discussed including placing the head above the heart, elevating the chin, using a head rest that is sufficiently firm, maximizing anesthesia care team access and minimizing fire risk, and taping the patient's head to the operating table to reduce unexpected movement with intraocular injury.

Factors to be Considered when Performing Cataract Surgery in Patients Unable to Recline Flat

PURPOSE

Although phacoemulsification is routinely performed with the patient in a supine position, certain locomotor deformities and other severe ailments can lead to the inability of the patient to recline flat.

METHODS

The present article surveys publications and summarizes our own experience regarding positioning techniques during cataract surgery on patients unable to adopt a supine position.

RESULTS

The successful and effective performance of cataract surgery by phacoemulsification depend on the comfortable positioning of both the patient and the surgeon. In order to achieve the highest possible success rate in phacoemulsification surgery, optimal positioning of the patient and the operating microscope are essential. There are other features of pivotal importance, including the construction of the operating table, the anesthesia technique, and the surgical approach.

CONCLUSIONS

Surgeons often have to rely on their own imagination and experience in finding optimal positioning in order to perform effective and successful phacoemulsification surgery.