Fluid-gas exchange and photocoagulation after vitrectomy. Indications, technique, and results

Intravitreal Ranibizumab Injection as an Adjuvant in the Treatment of Neovascular Glaucoma Accompanied by Vitreous Hemorrhage after Diabetic Vitrectomy

Purpose. To determine the efficacy of intravitreal ranibizumab injection as adjuvant therapy in the treatment of neovascular glaucoma (NVG) accompanied by postvitrectomy diabetic vitreous hemorrhage (PDVH). Methods. Eighteen NVG patients (18 eyes) accompanied by PDVH were enrolled in this prospective, monocenter, 12-month, interventional case series. The consecutive 18 patients with an IOP ≥ 25 mmHg despite being treated with the maximum medical therapy were treated with intravitreal ranibizumab injections. Vitreous surgery or/with Ahmed valve implantation were indicated if no clinical improvement in vitreous haemorrhage and uncontrolled IOP was shown. Results. Ten patients got clear vitreous and controlled IOP only with 2.7 ± 1.8 injections of ranibizumab without additional surgery. Vitrectomy or/with Ahmed valve implantation was administered in the other 8 eyes due to uncontrolled VH and IOP. At follow-up month 12, all the 18 eyes gained clear vitreous. At month 12 BCVA improved significantly compared to baseline. The baseline and follow-up at month 12 IOP/medication usage were 36.7 ± 8.1 mmHg on 3.4 ± 0.7 medications and 16.2 ± 4.9 mmHg on 0.67 ± 0.77 medications, respectively. Conclusions. The findings suggest that intravitreal ranibizumab injection as adjuvant therapy for treatment of NVG accompanied by PDVH may be safe and potentially effective. This clinical trial is registered with NCT02647515.

Anti-vascular endothelial growth factor for prevention of postoperative vitreous cavity haemorrhage after vitrectomy for proliferative diabetic retinopathy

BACKGROUND

Postoperative vitreous cavity haemorrhage (POVCH) is a significant complication following vitrectomy for proliferative diabetic retinopathy (PDR). It delays visual recovery and can make further treatment difficult if the view of the fundus is significantly obscured. A number of interventions to reduce the incidence of POVCH have been proposed, including the perioperative use of anti-vascular endothelial growth factor (anti-VEGF). Anti-VEGFs reduce vascular proliferation and the vascularity of neovascular tissue, which is often the source of bleeding following vitrectomy.

OBJECTIVES

This updated review aimed to summarise the effects of anti-VEGF use to reduce the occurrence of POVCH after vitrectomy surgery for PDR.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (2015, Issue 4), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to May 2015), PubMed (January 1966 to May 2015), EMBASE (January 1980 to May 2015), Latin American and Caribbean Health Sciences (LILACS) (January 1982 to May 2015), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov), and the the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 26 May 2015.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) and quasi-RCTs that looked at the use of anti-VEGFs and the incidence of POVCH in people undergoing vitrectomy for PDR.

DATA COLLECTION AND ANALYSIS

Both review authors independently assessed and extracted the data. We used standard methodological procedures expected by Cochrane.The primary outcomes of the review were the incidence of early and late POVCH following perioperative anti-VEGF administration. Secondary outcomes included best-corrected visual acuity at six months following surgery, the incidence of vitreous cavity washout or revision vitrectomy at six months, adverse effects of intervention (cataract, iris rubeosis and rubeotic glaucoma, retinal detachment, increased inflammation and systemic side effects), quality of life measures performed at least six months following vitrectomy, and density of POVCH.

MAIN RESULTS

The current review included 12 RCTs that looked at the pre- or intraoperative use of intravitreal bevacizumab to prevent postoperative vitreous haemorrhage during pars plana vitrectomy for complications of PDR. The studies were conducted in a variety of countries (three from Iran, two from Italy, two from Egypt, and the remaining from South Korea, USA, Mexico, Pakistan, and Japan). The inclusion criteria for entry into the studies were standard complications of proliferative retinopathy: non-clearing vitreous haemorrhage, tractional retinal detachment involving the macula, or combined tractional rhegmatogenous detachment. The included studies randomised a total of 654 eyes. The average age of the participants was 54 years.We identified methodological issues in all included studies. Risk of bias was highest for masking of participants and investigators (four studies were an 'open label' design), and a number of studies were unclear when describing randomisation methods and sequence allocation.Participants receiving intravitreal bevacizumab in addition to pars plana vitrectomy were less likely to experience early POVCH (grade 2) compared to people undergoing pars plana vitrectomy alone (risk ratio (RR) 0.28, 95% confidence interval (CI) 0.08 to 0.96, 2 studies, 144 eyes, high-quality evidence). This corresponds to an absolute effect of 130 fewer people (95% CI 167 fewer to 7 fewer) with early POVCH per 1000 people when treated with intravitreal bevacizumab. We saw similar results for all grades of POVCH (RR 0.35, 95% CI 0.23 to 0.53, 9 studies, 512 eyes) and when excluding cases where assessment of outcome was impossible due to presence of silicone oil (RR 0.34, 95% CI 0.19 to 0.60, 6 studies, 302 eyes).The effect of pre- or intraoperative intravitreal bevacizumab on the incidence of late postoperative haemorrhage was uncertain (RR 0.72, 95% CI 0.30 to 1.72, 3 studies, 196 eyes, low-quality evidence). The absolute effect was 55 fewer people (95% CI 138 fewer to 143 more) with late POVCH per 1000 people when treated with intravitreal bevacizumab. This outcome was rarer and was only reported in a few studies. We are currently unable to provide an estimate of the effect of intravitreal bevacizumab on postoperative visual acuity due to significant study heterogeneity.No local or systemic complications of intravitreal bevacizumab were reported by the RCTs. The risk of postoperative retinal detachment was lower in the participants treated with pre- or intraoperative bevacizumab (RR 0.46, 95% CI 0.19 to 1.08, 7 studies, 372 participants, low-quality evidence); the absolute effect was 49 fewer people (95% CI:73 fewer to 8 more) with postoperative retinal detachment per 1000 people when treated with intravitreal bevacizumab.

AUTHORS' CONCLUSIONS

The use of pre- or intraoperative bevacizumab lowers the incidence of early POVCH. The reported complications from its use appear to be low. Futher randomised studies that look at other anti-VEGF medications are ongoing and will strengthen the current review findings, giving both surgeons and patients evidence to guide treatment choices in the management of proliferative retinopathy.

Giant retinal tears

A giant retinal tear (GRT) is a full-thickness neurosensory retinal break that extends circumferentially around the retina for three or more clock hours in the presence of a posteriorly detached vitreous. Its incidence in large population-based studies has been estimated as 1.5% of rhegmatogenous retinal detachments, with a significant male preponderance, and bilaterality in 12.8%. Most GRTs are idiopathic, with trauma, hereditary vitreoretinopathies and high myopia each being causative in decreasing frequency. The vast majority of GRTs are currently managed with a pars plana vitrectomy; the use of adjunctive circumferential scleral buckling is debated, but no studies have shown a clear anatomical or visual advantage with its use. Similarly, silicone oil tamponade does not influence long-term outcomes when compared with gas. Primary and final retinal reattachment rates are achieved in 88% and 95% of patients, respectively. Even when the retina remains attached, however, visual recovery may be limited. Furthermore, fellow eyes of patients with a GRT are at higher risk of developing retinal tears and retinal detachment. Prophylactic treatment under these circumstances may be considered but there is no firm evidence of its efficacy at the present time.

Intravitreal bevacizumab injection for recurrent vitreous haemorrhage after diabetic vitrectomy

PURPOSE

To evaluate the efficacy of intravitreal bevacizumab in treating recurrent vitreous haemorrhage (VH) after diabetic vitrectomy.

METHODS

Consecutive patients with postoperative recurrent VH ≥ 2 weeks after primary diabetic vitrectomy were treated with intravitreal bevacizumab. Repeated injection was given after 2-3 weeks in case of no obvious blood reabsorption (study group). Consecutive patients with the same complication but without bevacizumab injection served as the control group. Vitreous surgeries in both groups were indicated if no clinical improvement was noted 10-12 weeks after the initial bleeding. Vitreous clear-up time (VCT), vitreous surgeries and rebleeding rates, and visual acuity changes were compared between both groups.

RESULTS

The study group had 20 eyes (20 patients) and the control group had 18 eyes (18 patients). Postoperative VH occurred between 1 and 25 months and between 1 and 18 months, respectively. In the study group, VCT after the first recurrent VH was 6.5 ± 1.5 weeks with 2.2 ± 0.8 injections. Nine cases had ≥ one episode of VH, but no surgery was needed. In the control group, 13 eyes had spontaneous re-absorption (in 6.4 ± 1.3 weeks); five eyes underwent surgeries; three of the 13 eyes eventually had surgeries after further recurrent VH. The rate of vitreous surgery in the two groups was 0/20 and 8/18 (p = 0.01). The total number of rebleeding was 30 in the study group and 27 in the control group (p = 0.69).

CONCLUSION

Intravitreal bevacizumab treatment may reduce the need of revitrectomy for recurrent vitreous haemorrhage after diabetic vitrectomy.

Anti-vascular endothelial growth factor for prevention of postoperative vitreous cavity haemorrhage after vitrectomy for proliferative diabetic retinopathy

BACKGROUND

Postoperative vitreous cavity haemorrhage (POVCH) is a significant complication following vitrectomy for proliferative diabetic retinopathy (PDR). It delays visual recovery and can make further treatment difficult if the view of the fundus is significantly obscured. A number of interventions to reduce the incidence of POVCH have been proposed, including the perioperative use of anti-vascular endothelial growth factor (anti-VEGF). Anti-VEGFs reduce vascular proliferation and the vascularity of neovascular tissue, which is often the source of bleeding following vitrectomy.

OBJECTIVES

The review aims to assess the effect of perioperative anti-VEGF in reducing the incidence of POVCH.

SEARCH STRATEGY

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2011, Issue 2), MEDLINE (January 1950 to March 2011), PubMed (10 March 2011), EMBASE (January 1980 to March 2011), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to March 2011), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com) and ClinicalTrials.gov (www.clinicaltrial.gov). There were no date or language restrictions in the electronic searches for trials. The electronic databases were last searched on 10 March 2011.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) that looked at the use of anti-VEGFs and the incidence of POVCH in people undergoing vitrectomy for PDR.

DATA COLLECTION AND ANALYSIS

Both review authors independently assessed and extracted the data using a standardised form based on the CONSORT statement.

MAIN RESULTS

We included four studies (202 eyes of 198 participants) in this review. The four RCTs met the inclusion criteria, but we were unable to conduct a meta-analysis due to methodological issues in three of the trials. We have provided a summary of the effects of the interventions. We have also provided a summary of the current literature addressing each primary and secondary outcome.

AUTHORS' CONCLUSIONS

Results from one of the included studies support the use of preoperative intravitreal bevacizumab to reduce the incidence of early POVCH. There are currently no other high quality RCTs that support the use of anti-VEGF agents perioperatively to reduce the incidence of early or late POVCH. The remaining studies identified by the search suggest that the preoperative use of bevacizumab may reduce the incidence of early POVCH, but it should be recognised that there are a number of significant methodological issues in these studies that lead us to be cautious when interpreting their findings and make any definitive conclusions unwarranted.

Reasons for and management of postvitrectomy vitreous hemorrhage in proliferative diabetic retinopathy

OBJECTIVE

To analyze the reasons for postvitrectomy vitreous hemorrhage in proliferative diabetic retinopathy (PDR), and to evaluate the effects of retreatment.

DESIGN

Retrospective, nonrandomized, observational case series.

METHODS

Three hundred and fifteen eyes of 302 consecutive patients underwent primary standard three-port vitrectomy with 20-gauge instruments for complications of PDR from 2000 to 2006. One hundred and forty-two patients were male, and 160 were female. The age ranged from 38 to 72 years with a mean of 56 years. There were 32 eyes which developed postvitrectomy vitreous hemorrhage during follow-up. The mean follow-up was 12 months with a range from 3 to 48 months.

RESULTS

Of 315 eyes with PDR and receiving pars plana vitrectomy, 32 eyes had postvitrectomy vitreous hemorrhage. The onset of recurrent vitreous hemorrhage ranged from 1 to 210 days with an average of 51 days. The reasons for postvitrectomy vitreous hemorrhage in PDR mainly included fibrovascular ingrowth at sclerotomy sites (9 eyes), residual or recurrent neovascular membrane on the optic nerve (6 eyes), insufficient retinal photocoagulation (7 eyes), residual and recurrent epiretinal proliferative membrane (3 eyes), retinal vein occlusion (2 eyes), postoperative low intraocular pressure (2 eyes), and ocular trauma (3 eyes). The visual acuity increased in 31 eyes (96.88%), and decreased in 1 eye (3.12%) after retreatment. The postoperative complications following the treatment of recurrent vitreous hemorrhage mainly included posterior synechia of the iris (3 eyes), nucleus sclerosis (18 eyes), and delayed healing of corneal epithelium (3 eyes).

CONCLUSION

Vitrectomy is a safe and effective method for treating PDR. Appropriate and complete analysis of postvitrectomy vitreous hemorrhage can significantly improve the primary treatment effects for PDR.

The efficacy of fluid-gas exchange for the treatment of postvitrectomy retinal detachment

Purpose

This study was designed to evaluate the efficacy of fluid-gas exchange for the treatment of postvitrectomy retinal detachment.

Methods

We retrospectively reviewed the records of 33 consecutive patients (35 eyes) who underwent fluid-gas exchange treatment for postvitrectomy retinal detachment using the two-needle pars plana approach technique.

Results

The retinal reattachment rate was 80.0% after complete intravitreal gas disappearance following the fluid-gas exchange; the overall success rate was 65.7%. Visual acuity was improved or stable in 80.0% of cases; a two-line or greater vision improvement or a best-corrected visual acuity of 0.4 or better occurred in 62.9% of cases. The success rates for superior retinal detachments and posterior pole retinal detachments were 76.5% and 85.7%, respectively.

Conclusions

Fluid-gas exchange represents a simple and cost-effective alternative outpatient procedure for retinal reattachment without reoperation for the treatment of superior and posterior pole retinal detachments.

[Fatal air embolism during open eye surgery]

Gas embolism is well known for a specific subset of surgical interventions. Prevention and early detection are the main objectives of the anesthetic and surgical team. However, it may exceptionally occur during eye surgery with dramatic outcomes. We report the case of a 51-year-old man, ASA physical status 1, who presented a cardiac arrest during an open eye surgery for the extraction of a foreign body with intraocular air injection. Multiple organ failure has not been improved by hyperbaric oxygen therapy and the outcome was fatal.

Cryotherapy of the Anterior Retina and Sclerotomy Sites in Diabetic Vitrectomy to Prevent Recurrent Vitreous Hemorrhage

OBJECTIVE

To evaluate the role of cryotherapy of the anterior retina and sclerotomy sites in the prevention of fibrovascular ingrowth (FVIG) at sclerotomy sites and postoperative recurrent vitreous hemorrhage in patients undergoing pars plana vitrectomy (PPV) for proliferative diabetic retinopathy (PDR).

DESIGN

Retrospective, nonrandomized, observational case series.

PARTICIPANTS

Eighty-one eyes in 71 patients who had undergone PPV for complications of PDR in the previous 2 years, with postoperative retinal reattachment for at least 3 months.

METHODS

Cases were divided into 3 groups: (1) having panretinal or supplementary endophotocoagulation; (2) having anterior peripheral retinal cryotherapy (ARC) in addition to panretinal endolaser treatment; and (3) having endophotocoagulation, ARC, and cryotherapy on the 3 sclerotomy sites added. Ultrasound biomicroscopy (UBM) examination of the 3 sclerotomy sites was performed > or =2 months after surgery. The UBM findings were separated into 4 categories: well-healed, gap, vitreous incarceration, and FVIG. History and management of recurrent vitreous hemorrhage were recorded.

MAIN OUTCOME MEASURES

Ultrasound biomicroscopy findings and the percentage of recurrent vitreous hemorrhage in the 3 groups were compared to determine the effectiveness of the adjunct cryotherapy in inhibiting FVIG and preventing recurrent vitreous hemorrhage.

RESULTS

The recurrent vitreous hemorrhage rates in groups 1, 2, and 3 were 12 of 32 (37.5%), 3 of 26 (11.5%), and 1 of 23 (4.3%), respectively (P = 0.0004). In each group, different sclerotomy sites had similar distributions of the 4 UBM categories. Among the 3 groups, gap was found in 9.4%, 20.5%, and 52.2% of eyes, respectively (P<0.001), whereas FVIG was found in 36.5%, 15.4%, and 0% of eyes (P<0.001). Fibrovascular ingrowth was noted in 87.5% (14/16) of all eyes experiencing recurrent vitreous hemorrhage. Of those with rebleeding but no FVIG (2 eyes), 1 had vitreous lavage combined with additional cryotherapy, and 1 had no treatment. Of those with FVIG (14 eyes), 5 needed > or =2 operations.

CONCLUSIONS

The presence of FVIG had good correlation with the development of recurrent postoperative vitreous hemorrhage. Anterior peripheral retinal cryotherapy combined with cryotherapy of sclerotomy sites might be helpful adjunct procedures in diabetic vitrectomy for inhibition of FVIG and prevention of recurrent vitreous hemorrhage.

Treatment of reopened macular hole after vitrectomy by laser and outpatient fluid-gas exchange

OBJECTIVE

This study aimed to assess a new nonsurgical treatment for patients who have previously undergone vitrectomy for macular hole with either persistent or reopened holes.

DESIGN

A prospective, noncomparative, consecutive case series.

PARTICIPANTS

Fifteen patients (15 eyes) were studied.

INTERVENTION

Patients were treated by an outpatient method consisting of laser photocoagulation to the foveal pigment epithelium followed by fluid-gas exchange with 20% perfluoropropane gas and prone positioning. Patients without known allergy were treated with two doses of oral Diamox (250 mg) and ciprofloxacin (500 mg).

MAIN OUTCOME MEASURES

Visual acuity, intraocular pressure, anatomic status of the macular hole, and cataract were the principal outcome measures studied.

RESULTS

Thirteen of 15 macular holes were closed successfully with 1 or more procedures. All patients with macular hole closure achieved two lines or greater of vision improvement on Snellen testing. Three patients (20%) achieved 20/40 and nine (60%) achieved 20/80 or better. Three patients required more than one procedure. Four patients developed mild transient ocular hypertension.

CONCLUSIONS

The combination of office-based outpatient fluid-gas exchange and laser appears to be a safe and cost-effective alternative to repeat surgery in selected patients with persistent or reopened macular holes after vitrectomy, in whom there are no visible epiretinal membranes, or in whom return to the operating room is undesirable for medical or personal reasons.

Light distribution of ocular endophotocoagulator probes and its surgical implications

Ophthalmic endophotocoagulator probe cone angle affects the spot size, working distance, laser output power requirement, tissue exposure time, and uniformity of tissue irradiance, which all affect ease and safety of clinical use. The cone angle and irradiance distribution of several ophthalmic endophotocoagulator delivery systems were studied by directing the laser energy emitted by them on a CCD video sensor at several angles of incidence. The irradiances followed a Gaussian distribution. The measured irradiances were compared to a mathematical model of tissue irradiance that adjusted for the cone angle, probe-tissue distance, and angle of incidence. Using this model, laser irradiances produced by endophotocoagulator probes can be estimated under a wide variety of conditions. At highly oblique angles of incidence, wide-angle probes produce unexpectedly higher and uneven tissue irradiance. When numerous characteristics are considered, probes with a cone angle in the range of 10 degrees have many advantages over narrower or wider angle probes.

Efficacy of fluid-air exchange for postvitrectomy diabetic vitreous hemorrhage

We reviewed the records of 33 fluid-air exchanges to assess the efficacy of fluid-air exchange in the management of recurrent vitreous cavity hemorrhage after vitrectomy for proliferative diabetic retinopathy. Fluid-air exchange alone was successful in clearing the vitreous cavity in ten of 20 eyes after a mean of 1.5 exchanges per eye. Repeat vitrectomy was required in the remaining ten eyes and anterior hyaloidal fibrovascular proliferation was frequently found. Hemorrhages that occurred in the late postoperative period (more than nine months) appeared more likely to be successfully treated with fluid-air exchange alone. Failure of the initial fluid-air exchange to induce clearing immediately after the procedure appeared to be associated with subsequent exchange failures and need for surgical intervention. Complications from the exchange procedure were infrequent with the development of peripheral retinal detachment in one eye. Our current recommendation for nonclearing recurrent postvitrectomy diabetic vitreous hemorrhage is to perform a fluid-air exchange, provided no other high-risk characteristics are present. If clearing occurs in the immediate postexchange period but rebleeding occurs at a later period, we recommend a second fluid-air exchange. If clearing does not occur in the immediate postexchange period, we recommend proceeding directly to revision of vitrectomy.

Vitreous replacement by gas as a therapeutic modality in bacterial endophthalmitis

We investigated vitreous replacement by long-lasting gas in the management of severe Staphylococcus aureus endophthalmitis in 19 rabbits randomized for vitrectomy (9 animals) and for vitrectomy followed by replacement of the vitreous by a 20% perfluoropropane-80% air mixture (10 animals). Both groups received systemic antibiotics and achieved comparable intraocular antibiotic levels. Clinically and histopathologically, gas-filled eyes demonstrated less inflammation than did eyes without gas (P less than 0.01). Replacement of vitreous by gas offers an effective adjunct to vitrectomy by eliminating a culture medium, preventing vitreous abscess formation, enabling fundus visualization, and delaying the onset of retinal detachment.

Methods, statistical features, and baseline results of a standardized, multicentered ophthalmologic surgical trial: the Silicone Study

This article describes the trial design and baseline results for the Silicone Study, a multicenter, randomized surgical trial designed to compare the effectiveness of silicone fluid versus long-acting gas in the treatment of proliferative vitreoretinopathy (PVR). Design features include (1) standardization of the surgical protocol to reduce intersurgeon variability, (2) formulation of a PVR clinical classification system relevant to modern vitreoretinal surgery, and (3) creation of a photographic protocol to document PVR pathology. Statistical issues affecting the analysis of the outcome data include (1) the addition of a second group of patients with more severely diseased eyes after the trial began, (2) the change to a different long-acting gas during the course of the trial, and (3) recurrent retinal detachments that require reoperations with the randomized treatment, and, in some instances, a crossover from the randomized to the alternate treatment. Demographic and baseline ocular characteristics are presented for the two groups under study.

The effect of scleral buckling on ocular rigidity

In a study of enucleated human eyes, the authors investigated the effect of scleral buckling on the ocular pressure-volume relationship. Intraocular pressure was recorded continuously during intravitreal infusion of saline solution before and after the application of encircling silicone elements. Scleral buckling produced a marked reduction in ocular rigidity, with reversibility of the effect on removal of the buckling elements. Similar results were obtained during incremental intravitreal air injection. The authors propose that the greater extensibility of silicone compared with sclera and the induced alterations in ocular shape are the primary factors responsible for the observed change in ocular rigidity. The clinical implications of these findings for intravitreal gas injection are discussed.

Subretinal membranes in proliferative vitreoretinopathy

Subretinal membranes (SRMs) are an important but rarely identified component of proliferative vitreoretinopathy (PRV). In 153 consecutive cases that had vitreoretinal surgery for this condition and were followed for at least 6 months, SRMs were encountered in 72 eyes (47%). In 20 (28%) of the 72 eyes, the SRMs prevented complete retinal reattachment and needed to be removed or excised through one or multiple retinotomies. Intraoperative complications related to the SRMs or their removal included choroidal or retinal hemorrhage in three eyes (15%), subretinal air in three eyes (15%), and unplanned extension of the retinotomies in two eyes (10%). The 20 eyes requiring SRMs removal were followed for a median of 11 months. Retinas were reattached in 13 eyes (65%), although only 4 eyes (20%) had a visual acuity of 5/200 or better. Recognizing SRMs as a component of PVR is important in helping to maximize the anatomic success rate although the effects on visual function are not fully known.

Vitrectomy for retinal detachment associated with acute retinal necrosis

Six patients with retinal detachment associated with the acute retinal necrosis syndrome were treated by the combination of vitrectomy, gas injection, and laser photocoagulation. The retinas were successfully reattached in each patient with one operation. Five of the patients achieved a visual acuity of 20/200 or better, and three had a visual acuity of 20/40 or better.

Repeated fluid-gas exchange for hypotony after vitreoretinal surgery for proliferative vitreoretinopathy

Three patients with prolonged hypotony after vitreoretinal surgery for proliferative vitreoretinopathy were treated with repeated fluid-gas exchanges to maintain intraocular pressure and prevent the development of phthisis bulbi. We performed fluid-gas exchanges solely to treat the hypotony beyond the period when tamponade of retinal breaks was required, and without specific positioning of the bubble. In these patients, the intraocular pressure eventually returned to normal and useful vision was retained.

Intraoperative use of pure perfluoropropane gas in the management of proliferative vitreoretinopathy

A single-step technique for fluid-gas exchange with pure perfluoropropane gas in proliferative vitreoretinopathy (PVR) is described. The technique was used in 38 eyes of 38 patients. Permanent and total retinal reattachment, with a minimum follow-up of 6 months after gas disappearance, was achieved in 24 eyes (63%). The anatomical success rate was 80.9% (17/21 eyes) in PVR grade C and 41% (7/17 eyes) in PVR grade D. Twenty-two of the successful eyes (92%) underwent a single operation. Thirteen of the successful eyes (54%) obtained final visual acuities of 0.1 or better. Severe increase of intraocular pressure postoperatively, due to overestimation of the intraocular space available for gas expansion, is a potential risk of the technique. This risk should be avoided by means of preoperative evaluation of the vitreous cavity volume with A-scan ultrasonography and intraoperative measurement of the intraocular fluid volume displaced by scleral buckling.