Glucocorticosteroid inhibition of intraocular proliferation after injury

Efficacy of 5-fluorouracil (5-FU) and low molecular weight heparin (LMWH) in high-risk pediatric retinal detachment; randomized clinical trial

BACKGROUND

Pediatric rhegmatogenous retinal detachments (PRRDs) are complex, rare occurrences and are often related to trauma or congenital abnormalities. Children often do not recognize or report symptoms of retinal detachment. Thus at presentation, PRRD is typically advanced often with macular involvement, proliferative vitreoretinopathy (PVR), chronic duration, and poor visual acuity. Because 5-FU and LMWH are effective in different aspects in the PVR process, it was believed that a syngergistic approach to the prevention of PVR would be advantageous.

METHODS

After informed consent, children under 14 years of age with high-risk PRRD underwent pars plana vitrectomy and silicone oil injection with scleral buckle divided into 2 groups in prospective randomized trial. Group A received intraoperative infusion of 5-FU (200 µg/ml) and LMWH (5 IU/ml), group B received infusion of normal saline. Primary outcome was occurrence of recurrent PRRD within 12 weeks, secondary outcomes were occurrence of PVR, best corrected visual acuity (BCVA), number and timing of secondary procedures within 12 weeks.

RESULTS

The study included 42 eyes of 41 patients, 21 in group A and 21 in group B, the duration of PRRD ranged from 0.5 to 7 months in group A and 0.25-5 months in group B.The rate of recurrent PRRD was higher in group B 33% compared to 19% in group A (p = 0.292). The mean timing of occurrence of recurrent PRRD was 9.5 ± 5 weeks in group A compared to 2.86 ± 2.41 weeks in group B (p = 0.042), more patients in group B ended up with more advanced PVR (p = 0.038), BCVA was hand movement (HM) only in all cases preoperatively and improved to HM-0.3 Snellen in group A compared to light perception (PL)-0.1Snellen in group B (p = 0.035), there was no difference in any of secondary procedures but with later timing in group A 9.71 ± 3.73 weeks than in group B 4.0 ± 2.83 weeks (p = 0.042).

CONCLUSION

This study concluded that the use of the 5-FU and LMWH combination in high risk PRRD resulted in lower rate of postoperative PVR, later recurrence of PRRD and better final BCVA.

TRIAL REGISTRATION NUMBER

Registry: clinicaltrials.gov PRS NCT06166914 date of initial release 4/12/2023. Unique Protocol ID: 9,163,209 date 21/10/2021. Retrospectively registered.

Randomised controlled trial of adjunctive triamcinolone acetonide in eyes undergoing vitreoretinal surgery following open globe trauma: The ASCOT study

BACKGROUND/AIMS

To investigate the clinical effectiveness of adjunctive triamcinolone acetonide (TA) given at the time of vitreoretinal surgery following open globe trauma (OGT).

METHODS

A phase 3, multicentre, double-masked randomised controlled trial of patients undergoing vitrectomy following OGT comparing adjunctive TA (intravitreal and subtenons) against standard care (2014-2020). The primary outcome was the proportion of patients with at least 10 Early Treatment Diabetic Retinopathy Study (ETDRS) letter improvement in corrected visual acuity (VA) at 6 months. Secondary outcomes included: change in ETDRS, retinal detachment (RD) secondary to PVR, retinal reattachment, macular reattachment, tractional RD, number of operations, hypotony, elevated intraocular pressure and quality of life.

RESULTS

280 patients were randomised over 75 months, of which 259 completed the study. 46.9% (n=61/130) of patients in the treatment group had a 10-letter improvement in VA compared with 43.4% (n=56/129) of the control group (difference 3.5% (95% CI -8.6% to 15.6%), OR=1.03 (95% CI 0.61 to 1.75), p=0.908)). Secondary outcome measures also failed to show any treatment benefit. For two of the secondary outcome measures, stable complete retinal and macular reattachment, outcomes were worse in the treatment group compared with controls, respectively, 51.6% (n=65/126) vs 64.2% (n=79/123), OR=0.59 (95% CI 0.36 to 0.99), and 54.0% (n=68/126) vs 66.7% (n=82/123), OR=0.59 (95% CI 0.35 to 0.98), for TA vs control.

CONCLUSION

The use of combined intraocular and sub-Tenons capsule TA is not recommended as an adjunct to vitrectomy surgery following OGT.

TRIAL REGISTRATION NUMBER

NCT02873026.

Efficacy and Safety of Intravitreal Conbercept, Ranibizumab, and Triamcinolone on 23-Gauge Vitrectomy for Patients with Proliferative Diabetic Retinopathy

Introduction

To compare the effect and safety of intravitreal conbercept (IVC), intravitreal ranibizumab (IVR), or intravitreal triamcinolone acetonide (IVTA) injection on 23-gauge (23-G) pars plana vitrectomy (PPV) for proliferative diabetic retinopathy (PDR).

Methods

Fifty patients (60 eyes) of varying degrees of PDR were randomly grouped into 3 groups (1 : 1 : 1) (n = 20 in each group). The 23-G PPV was performed with intravitreal conbercept or ranibizumab injection 3–7 days before surgery or intravitreal TA injection during surgery. The experiment was randomized controlled, with a noninferiority limit of five letters. Main outcome measures included BCVA, operation time, incidence of iatrogenic retinal breaks, endodiathermy rate, and silicone oil tamponade.

Results

At 6 months after surgery, there were no significant differences of BCVA improvements, operation time, incidence of iatrogenic retinal breaks, endodiathermy rate, silicone oil tamponade, vitreous clear-up time, and the incidence of intraoperative bleeding between the IVC and IVR groups (all P values ≥ 0.05), but they were significantly different from the IVTA group (all P values < 0.05). IOP increases did not show significant differences between the IVC and IVR groups, but both were significantly different with the IVTA group. More patients had higher postoperative IOP in the IVTA group.

Conclusions

The intravitreal injection of conbercept, ranibizumab, or TA for PDR had a significant different effect on outcomes of 23-G PPV surgery. Conbercept and ranibizumab can reduce difficulty of the operation, improve the success rate of PPV surgery, and decrease the incidence of postoperative complications.

Slow-Release Dexamethasone in Proliferative Vitreoretinopathy: A Prospective, Randomized Controlled Clinical Trial

PURPOSE

To test the hypothesis that adjunctive slow-release dexamethasone implant (Ozurdex; Allergan Inc, Irvine, CA) can improve the outcomes of vitreoretinal surgery for established proliferative vitreoretinopathy (PVR).

DESIGN

A 2-year, single-center, prospective, participant- and surgeon-masked randomized controlled clinical trial (EudraCT No. 2011-004498-96).

PARTICIPANTS

A total of 140 patients requiring vitrectomy surgery with silicone oil for retinal detachment with established PVR (Grade C) were randomized to standard (control) or study treatment (adjunct) in a 1:1 allocation ratio.

METHODS

Intraoperatively, the adjunct group received an injection of 0.7 mg of slow-release dexamethasone (Ozurdex) at the time of (1) vitrectomy surgery and (2) silicone oil removal. The control group received standard care.

MAIN OUTCOME MEASURES

Primary outcome measure was the proportion of patients with a stable retinal reattachment with removal of silicone oil without additional vitreoretinal surgical intervention at 6 months. Secondary outcomes included (1) final visual acuity (VA) (median and Early Treatment Diabetic Retinopathy Study [ETDRS] of 55 letters or better); (2) cystoid macular edema (CMO), foveal thickness, and macular volume; (3) development of overt PVR recurrence; (4) complete and posterior retinal reattachment; (5) tractional retinal detachment; (6) hypotony/increased intraocular pressure (IOP); (7) macula pucker/epiretinal membrane; (8) cataract; and (9) quality of life.

RESULTS

All 140 patients were recruited within 25 months of study commencement; 138 patients had primary outcome data. Primary outcome assessment showed similar results in anatomic success between the 2 groups (49.3% vs. 46.3%, adjunct vs. control; odds ratio, 0.89; 95% confidence interval, 0.46-1.74; P = 0.733). Mean VA at 6 months was 38.3 ETDRS letters and 40.2 letters in the adjunct and control groups, respectively. Secondary anatomic outcomes (complete/posterior reattachment rates and PVR recurrence) were comparable between the 2 groups. At 6 months, fewer adjunct patients had CMO (42.7%) or a foveal thickness of >300 μm (47.6%) compared with controls (67.2% and 67.7%, respectively, P = 0.004, P = 0.023).

CONCLUSIONS

A slow-release dexamethasone implant did not improve the primary anatomic success rate in eyes undergoing vitrectomy surgery with silicone oil for PVR. Further clinical trials are indicated to improve anatomic and visual outcomes in these eyes, but this study suggests that there is a greater reduction in CMO observed at 6 months in vitrectomized eyes treated with slow-release dexamethasone.

Proliferative vitreoretinopathy: A new concept of disease pathogenesis and practical consequences

During the last four decades, proliferative vitreoretinopathy (PVR) has defied the efforts of many researchers to prevent its occurrence or development. Thus, PVR is still the major complication following retinal detachment (RD) surgery and a bottle-neck for advances in cell therapy that require intraocular surgery. In this review we tried to combine basic and clinical knowledge, as an example of translational research, providing new and practical information for clinicians. PVR was defined as the proliferation of cells after RD. This idea was used for classifying PVR and also for designing experimental models used for testing many drugs, none of which were successful in humans. We summarize current information regarding the pathogenic events that follow any RD because this information may be the key for understanding and treating the earliest stages of PVR. A major focus is made on the intraretinal changes derived mainly from retinal glial cell reactivity. These responses can lead to intraretinal PVR, an entity that has not been clearly recognized. Inflammation is one of the major components of PVR, and we describe new genetic biomarkers that have the potential to predict its development. New treatment approaches are analyzed, especially those directed towards neuroprotection, which can also be useful for preventing visual loss after any RD. We also summarize the results of different surgical techniques and clinical information that is oriented toward the identification of high risk patients. Finally, we provide some recommendations for future classification of PVR and for designing comparable protocols for testing new drugs or techniques.

Ozurdex (a slow-release dexamethasone implant) in proliferative vitreoretinopathy: study protocol for a randomised controlled trial

Background

Proliferative vitreoretinopathy (PVR) is the commonest cause of late anatomical failure in rhegmatogenous retinal detachment. Visual and anatomical outcomes remain poor despite advances in vitreoretinal surgical techniques with reported primary failure rates of up to nearly 50%. Numerous adjunctive medications have been evaluated in clinical trials with no agent gaining widespread acceptance and use.

This study was designed to investigate the benefits of using a slow-release dexamethasone implant delivered intra-operatively in patients undergoing vitrectomy surgery for retinal detachment with established PVR.

Methods/design

For the study, 140 patients requiring vitrectomy surgery with silicone oil for retinal detachment with established PVR will be randomised to receive either standard treatment or study treatment in a 1:1 treatment allocation ratio. Both groups will receive the standard surgical treatment appropriate for their eye condition and routine peri-operative treatment and care, differing only in the addition of the supplementary adjunctive agent in the treatment group. The investigated primary outcome measure is stable retinal reattachment with removal of silicone oil without additional vitreoretinal surgical intervention at 6 months.

Discussion

This is the first randomised controlled clinical trial to investigate the use of an adjunctive slow-release dexamethasone implant in patients undergoing vitrectomy surgery for retinal detachments with proliferative vitreoretinopathy.

Trial registration

EudraCT No: 2011-004498-96.

A pilot study of intraocular use of intensive anti-inflammatory; triamcinolone acetonide to prevent proliferative vitreoretinopathy in eyes undergoing vitreoretinal surgery for open globe trauma; the Adjuncts in Ocular Trauma (AOT) Trial: study protocol for a randomised controlled trial

BACKGROUND

Eyes sustaining open globe trauma (OGT) is a group at high risk of severe visual impairment. Proliferative vitreoretinopathy (PVR) is the commonest cause of retinal redetachment in these eyes and is reported to occur in up to 45% of cases. Intensive anti-inflammatory agents have been shown to be effective at modifying experimental PVR and to be well tolerated clinically.The Adjuncts in Ocular Trauma (AOT) Trial was designed to investigate the benefits of using intensive anti-inflammatory agents (intravitreal and sub-Tenon's triamcinolone, oral flurbiprofen and guttae prednisolone 1.0%) perioperatively in patients undergoing vitrectomy surgery following open globe trauma.

METHODS/DESIGN

Patients requiring posterior vitrectomy surgery following open globe trauma will be randomised to receive either standard treatment or study treatment. Both groups will receive the standard surgical treatment appropriate for their eye condition and routine perioperative treatment and care, differing only in the addition of supplementary adjunctive agents in the treatment group. The investigated primary outcome measure is anatomical success at 6 months in the absence of internal tamponade.

DISCUSSION

This is the first randomised controlled clinical trial to investigate the use of adjunctive intensive antiinflammatory agents in patients undergoing vitrectomy following open globe trauma. It will provide evidence for the role of these adjuncts in this group of patients, as well as provide data to power a definitive study. EUDRACT NO: 2007/005138/35.

Intravitreal low molecular weight heparin and 5-Fluorouracil for the prevention of proliferative vitreoretinopathy following retinal reattachment surgery

BACKGROUND

Proliferative vitreoretinopathy (PVR) is a significant cause of failure in retinal reattachment surgery. Various pharmacological agents have shown potential benefit in reducing postoperative PVR risk.

OBJECTIVES

This review aimed to compare the use of intravitreal low molecular weight heparin (LMWH) alone or with 5-Fluorouracil (5-FU) versus placebo, as an adjunct in the prevention of PVR following retinal reattachment surgery.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2012, Issue 9), MEDLINE (January 1950 to October 2012), EMBASE (January 1980 to October 2012), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (www.clinicaltrials.gov) and the 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 15 October 2012.

SELECTION CRITERIA

We only included randomised controlled trials (RCTs) that compared intravitreal LMWH alone or with 5-FU, versus placebo for the prevention of postoperative PVR in patients undergoing primary vitrectomy for rhegmatogenous retinal detachment repair.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. The review authors contacted study authors for additional information.

MAIN RESULTS

We included two RCTs (with a total of 789 participants) comparing LMWH with 5-FU infusion and placebo. However, we did not perform a meta-analysis because of significant heterogeneity between these studies. One study found a significant beneficial effect of LMWH with 5-FU in reducing postoperative PVR compared to placebo (RR: 0.48, 95% confidence interval: 0.25 to 0.92), in 174 patients who were viewed at high-risk of developing postoperative PVR. The other study included 615 unselected cases of rhegmatogenous retinal detachment and could not show a difference between LMWH with 5-FU infusion and placebo in reducing PVR rates (RR:1.45, 95% confidence interval: 0.76 to 2.76).

AUTHORS' CONCLUSIONS

Results from this review indicate that there is inconsistent evidence from two studies on patients at different risk of PVR on the effect of LMWH and 5-FU used during vitrectomy to prevent PVR. Future research should be conducted on high risk patients only, until a benefit is confirmed at least in this patient subgroup.

Intravitreal low molecular weight heparin and 5-Fluorouracil for the prevention of proliferative vitreoretinopathy following retinal reattachment surgery

BACKGROUND

Proliferative vitreoretinopathy (PVR) is a significant cause of failure in retinal reattachment surgery. Various pharmacological agents have shown potential benefit in reducing postoperative PVR risk.

OBJECTIVES

This review aimed to compare the use of intravitreal low molecular weight heparin (LMWH) alone or with 5-Fluorouracil (5-FU) versus placebo, as an adjunct in the prevention of PVR following retinal reattachment surgery.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2010, Issue 5), MEDLINE (January 1950 to May 2010), EMBASE (January 1980 to May 2010), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com) and ClinicalTrials.gov (http://clinicaltrials.gov). There were no language or date restrictions in the search for trials. The electronic databases were last searched on 24 May 2010.

SELECTION CRITERIA

We only included randomised controlled trials (RCTs) that compared intravitreal LMWH alone or with 5-FU, versus placebo for the prevention of postoperative PVR in patients undergoing primary vitrectomy for rhegmatogenous retinal detachment repair.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. The review authors contacted study authors for additional information.

MAIN RESULTS

We included two RCTs (with a total of 789 participants) comparing LMWH with 5-FU infusion and placebo. However, we did not perform a meta-analysis because of significant heterogeneity between these studies. One study found a significant beneficial effect of LMWH with 5-FU in reducing postoperative PVR compared to placebo (RR: 0.48, 95% confidence interval: 0.25 to 0.92), in 174 patients who were viewed at high-risk of developing postoperative PVR. The other study included 615 unselected cases of rhegmatogenous retinal detachment and could not show a difference between LMWH with 5-FU infusion and placebo in reducing PVR rates (RR:1.45, 95% confidence interval: 0.76 to 2.76).

AUTHORS' CONCLUSIONS

Results from this review indicate that there is inconsistent evidence from two studies on patients at different risk of PVR on the effect of LMWH and 5-FU used during vitrectomy to prevent PVR. Future research should be conducted on high risk patients only, until a benefit is confirmed at least in this patient subgroup.

Triamcinolone acetonide in ocular therapeutics

Triamcinolone acetonide has been effectively used in ocular therapeutics for over 50 years. Its use has increased dramatically in recent years for periocular and intraocular treatment of retinal vasculature disease and uveitis. This comprehensive review discusses the pharmacokinetics of triamcinolone acetonide and summarizes its uses in a number of diseases, both intraocular and extraocular. It discusses side effects and their management. Finally, it discusses the controversy over its use.

Long-term clinical outcomes and therapeutic benefits of triamcinolone-assisted pars plana vitrectomy for proliferative vitreoretinopathy: a case study

PURPOSE

To investigate intraoperative visibility and long-term clinical outcome following triamcinolone acetonide (TA)-assisted pars plana vitrectomy (PPV) for proliferative vitreoretinopathy (PVR).

METHODS

A retrospective interventional noncomparative clinical study was carried out on 21 eyes from 21 patients with more than grade C2 PVR, all of whom underwent TA-assisted PPV. Two of the specimens were observed with an electron microscope. After treatment, outcome measures, including changes in best-corrected visual acuity (BCVA), intraocular pressure (IOP) elevation, corneal pathology, and occurrence of endophthalmitis, were recorded. Patient follow-up time was >36 months (mean +/-standard deviation = 47.3 +/- 6.7 months).

RESULTS

TA improved the intraoperative visualization of the epiretinal membrane (ERM), allowing it to be easily removed together with the partially internal limiting membrane (ILM) using micro forceps. The excised tissue consisted of proliferative cells and an extracellular matrix underlying the ILM. After the operation, 71.4% of the eyes had improved BCVA. Three of the eyes showed sustained IOP elevation (14.3%); two of these cases were controlled by the administration of eyedrops, while the third required filtering surgery. In two cases, an absorption delay of the TA granule on the retinal surface was observed. One eye developed corneal stromal opacity. No other severe complications occurred during the observation period.

CONCLUSIONS

TA-assisted PPV offers improved visualization during the surgical management of PVR, and allows surgeons to excise the ERM safely and effectively without the risk of serious complications.

Ascorbic acid concentration in rabbit vitreous measured by microdialysis with HPLC-electrochemical detection before and after vitreous surgery

Microdialysis with high performance liquid chromatography and electrochemical detection (HPLC-ECD) was used to measure ascorbic acid (AA) concentrations in rabbit vitreous before and after vitrectomy. A cellulose microdialysis probe was implanted in the vitreous humor, and after stabilization, AA measurements were made daily over a 10 day period. The effect of removing two-thirds of the vitreous by vitrectomy was examined. The effect of triamcinolone acetonide (TA) was evaluated in four groups of rabbits: Group 1, sub-tenon TA (20 mg) alone; Group 2, intravitreous TA (4 mg) alone; Group 3, sub-tenon TA (20 mg) after vitrectomy, and Group 4, intravitreous TA (4 mg) after vitrectomy. The results showed that the AA concentration after vitrectomy was significantly lower from days 2 to 10 with a maximum reduction of 49.5% (P < 0.005) on day 7. No significant changes in the AA level was observed in Groups 1 and 2, a mild recovery of AA concentration reduction after vitrectomy was detected in Group 3. The highest recovery of the AA concentration reduction was observed in Group 4. The attenuating effect of TA treatment on the reduction of AA in the vitreous after vitrectomy was significant. This attenuating effect of the TA may be due to prevention of the disruption of the blood-aqueous barrier by its anti-inflammatory action.

[Pharmacological adjuvants for surgical treatment of proliferative vitreoretinopathy]

Proliferative vitreoretinopathy (PVR) is the major cause of retinal detachment surgery failure. Many adjuvants were studied in vitro and on animals, some were studied on humans. Daunomycin seems to reduce PVR recidivism. 5-FU and steroids are nontoxic but their efficacy is not clear. Heparin reduced postoperative inflammation and seems to reduce PVR recidivism when associated with 5-FU. Associating heparin and steroids seems to reduce PVR in some groups of patients (aphakic, anterior PVR). Colchicine and retinoic acid per os are ineffective, silicone oil is effective as an internal tamponade but not as an adjuvant of PVR. Currently, no molecule has proven efficacy as an adjunctive treatment of PVR.

INTRAVITREAL CONCENTRATION AND CLEARANCE OF TRIAMCINOLONE ACETONIDE IN NONVITRECTOMIZED HUMAN EYES

PURPOSE

To determine the intravitreal concentration and clearance of triamcinolone acetonide at various intervals after intravitreal injection into nonvitrectomized eyes.

METHODS

Six participants were administered 4 mg (0.1 cc) of triamcinolone acetonide ophthalmic suspension. All six eyes underwent therapeutic pars plana vitrectomy with membranectomy at various post injection intervals ranging from 1.25 to 5 months from the intravitreal injection. Undiluted specimens of vitreous overlying the macula and of aqueous humor were submitted for analysis. Vitreous and aqueous humor concentrations of triamcinolone were measured by high performance liquid chromatography.

RESULTS

Four eyes demonstrated detectable intravitreal concentrations of triamcinolone acetonide between 1.25 and 2.75 months after a single injection. Two eyes had an undetectable level of triamcinolone in both the vitreous and aqueous at 3 and 5 months post single injection.

CONCLUSIONS

The intravitreal concentration of triamcinolone acetonide is detectable up to 2.75 months post a single 4 mg injection in nonvitrectomized eyes. A reinjection interval of 3 months may be needed to achieve sustained measurable levels of triamcinolone in nonvitrectomized patients.

Possible Benefits of Triamcinolone-Assisted Pars Plana Vitrectomy for Retinal Diseases

PURPOSE

To study the advantages and complications of triamcinolone acetonide (TA)-assisted pars plana vitrectomy (PPV) for various retinal diseases.

METHODS

This report is an interventional case series and nonrandomized study. One hundred seventy-seven eyes from 158 patients underwent PPV with or without TA. Group TA(+) consisted of 94 eyes and group TA(-) consisted of 83 eyes. The improvement in vision and postoperative complications were prospectively studied.

RESULTS

Sixty-two percent of the eyes in group TA(+) and 49% of the eyes in group TA(-) had improved vision after surgery (P = 0.34). Twelve eyes in group TA(+) and 12 eyes in group TA(-) had an intraocular pressure higher than 21 mmHg after the operation, with no statistically significant difference (P = 0.63). Four eyes with proliferative diabetic retinopathy in group TA(+) and five eyes with proliferative diabetic retinopathy in group TA(-) needed an additional filtering surgery. Group TA(+) (five eyes) had a lower incidence (P = 0.041) of reoperation caused by preretinal fibrous membrane formation than group TA(-) (13 eyes). No apparent corneal disorder or infectious signs were found in any eyes.

CONCLUSIONS

Triamcinolone acetonide-assisted PPV appears to be potentially useful to reduce the incidence of reoperation owing to preretinal fibrosis with no serious complications.

Pars plana vitrectomy assisted by triamcinolone acetonide for refractory uveitis: a case series study

AIM

To examine the outcome of a triamcinolone acetonide (TA) assisted pars plana vitrectomy (PPV) for refractory uveitis.

METHODS

Six patients suffering from proliferative vitreoretinopathy (PVR) with refractory uveitis underwent a TA assisted PPV. The patients consisted of one with Vogt-Koyanagi-Harada disease, one with acute retinal necrosis, one with Behçet's disease, and three with sarcoidosis. TA was inoculated into the vitreous cavity to visualise the vitreous. In four of six patients, 4 mg of TA were intentionally left in the vitreous cavity to reduce the degree of postoperative inflammation.

RESULTS

The vitreous body was clearly seen using TA during surgery, which greatly helped us to perform a posterior hyaloid resection safely and thoroughly. As we previously observed in other disease, TA allowed us to visualise the transparent vitreous and thus was helpful in removing the vitreous cortex from the retina completely in uveitis. One patient (Behçet's disease, in whom TA was intentionally left) showed an elevated intraocular pressure (IOP) transiently after surgery which was controllable by topical eye drops. The remaining TA diminished day by day and had almost completely disappeared within a month from operation.

CONCLUSION

TA improved the visibility of the hyaloid and the safety of the surgical procedures and no serious complications were observed after TA assisted PPV in uveitis. Although the long term effects are still unknown, this method appears to be potentially useful as an improved treatment for PVR associated with refractory uveitis.

Simple retinal detachments: identifying the at-risk case

The success rate of retinal reattachment surgery has now reached over 90%. The major cause of failure is attributable to the development of proliferative vitreoretinopathy (PVR). It is a complex process comprised of events that are similar to those of the wound healing response with inflammation, migration and proliferation of a variety of cells. These membranes can exert traction and reopen previously closed retinal breaks, create new breaks, and distort or obscure the macula. In the early part of this century the success rate of retinal reattachment surgery was virtually nil and it was not until a better understanding of the pathophysiology of retinal detachment was gained that the success rate improved. It was Gonin who emphasised the relationship between vitreous detachment and traction resulting in retinal tears that led to treatment aimed at closing retinal breaks. To increase even further the final success rate in the treatment of 'simple retinal detachments' a better understanding of the risk factors for PVR is needed in patients presenting with acute retinal detachments. Such risk factors can be broadly divided under the headings of preoperative risk factors, best surgical management and possibly adjuvant therapy.

Regression of neovascular iris vessels by intravitreal injection of crystalline cortisone

PURPOSE

To report the clinical outcome of patients who received an intravitreal injection of crystalline triamcinolone acetonide as treatment of neovascular glaucoma.

PATIENTS AND METHODS

The study included 14 eyes of 14 patients with secondary neovascular glaucoma attributable to proliferative diabetic retinopathy (n = 9) or ischemic central retinal vein occlusion (n = 5). All patients received an intravitreal injection of 20 mg of crystalline triamcinolone acetonide as the only procedure (n = 4) or in combination with additional procedures, such as goniosynechiolysis (n = 1), phacoemulsification and intraocular lens implantation (n = 2), or transscleral peripheral retinal cryocoagulation (n = 7). Mean follow-up time was 3.10 +/- 2.40 months (median, 3.5 months; range, 0.50-5.7 months). A goniosynechiolysis was carried out in those patients in whom the anterior chamber was circumferentially closed.

RESULTS

After surgery, including the first days after surgery, the patients were nearly pain-free. Intraocular pressure was significantly (P < 0.01) reduced from 33.4 +/- 14.5 mm Hg before surgery to 20.7 +/- 8.2 mm Hg at the end of the follow-up period. Postoperative visual acuity (mean, 0.09 +/- 0.07; median, 0.10; range, finger counting to 0.25) was slightly but not significantly (P = 0.31) better than the preoperative values. Degree of rubeosis iridis decreased significantly (P = 0.02) from 2.6 +/- 1.3 relative units to 1.3 +/- 1.2 relative units. When considering only the four patients for whom the intraocular cortisone injection was the only procedure performed, mean intraocular pressure decreased from 26.5 +/- 12.1 mm Hg to 21.75 +/- 11.3 mm Hg.

CONCLUSIONS

Intravitreal injection of crystalline cortisone with most of the vehicle removed may be a potentially useful additional tool in the treatment of neovascular glaucoma.

Induction of interleukin-8 in human retinal pigment epithelial cells after denuding injury

AIM

To determine interleukin 8 (IL-8) and monocyte chemoattractant protein 1 (MCP-1) expression in response to mechanical injury in human retinal pigment epithelial (HRPE) cells.

METHODS

Enzyme linked immunosorbent assay (ELISA) was performed to determine IL-8 and MCP-1 secretion by HRPE cells after mechanical denudation. IL-8 and MCP-1 mRNA expression by HRPE cells was assessed using semiquantitative RT-PCR. The effects of immunosuppressive drugs, dexamethasone (DEX) and cyclosporin A (CSA), as well as immunosuppressive cytokines, interleukin 4 (IL-4), interleukin 10 (IL-10), and interleukin 13 (IL-13), on chemokine expression in HRPE cells after denuding injury were analysed.

RESULTS

Mechanical injury induced HRPE IL-8 mRNA and IL-8 secretion. Although MCP-1 mRNA was enhanced slightly after denuding injury, MCP-1 secretion was not increased. DEX and CSA inhibited HRPE chemokine expression after injury. IL-4 and IL-13 enhanced IL-8 and MCP-1 production by HRPE cells after injury while IL-10 had no effect.

CONCLUSIONS

These results suggest that IL-8 may be involved in retinal inflammatory responses to injury and that DEX and/or CSA treatment may help control the inflammatory components of retinal diseases such as proliferative vitreoretinopathy.

Adjuvant 5-fluorouracil and heparin prevents proliferative vitreoretinopathy : Results from a randomized, double-blind, controlled clinical trial

PURPOSE

To assess the safety and efficacy of adjuvant combination therapy using 5-fluorouracil (5-FU) and low molecular weight heparin (LMWH) for prevention of proliferative vitreoretinopathy (PVR) after vitrectomy and retinal reattachment surgery.

DESIGN

Prospective randomized, double-masked, placebo controlled trial.

PARTICIPANTS

One hundred seventy-four high-risk patients were randomized to receive either 5-FU and LMWH therapy or placebo. Patients were selected from all patients undergoing primary vitrectomy for rhegmatogenous retinal detachment.

METHOD

Results of standard surgery with 5-FU and LMWH therapy or placebo were compared at the 6-month follow-up.

MAIN OUTCOME MEASURES

Development of postoperative PVR, retinal reattachment at 6 months after surgery, single operation reattachment rate, number of reoperations, and best-corrected visual acuity.

RESULTS

There were 87 patients in the 5-FU and LMWH therapy group and 87 in the placebo group. The incidence of postoperative PVR was significantly lower (P = 0.02) in the 5-FU and LMWH therapy compared with the placebo group. In 26.4% (23/87) of the placebo group and in 12.6% (11/87) of the 5-FU and LMWH group, postoperative PVR developed. In the 5-FU and LMWH group, the number of patients undergoing more than one operation was 19.5% (17/87) and the number of reoperations resulting from PVR was 52.9% (9/17). In the placebo group, the number of patients undergoing more than one operation was 25.3% (22/87) and the number of reoperations resulting from PVR was 72.7% (16/22). The difference in visual acuity was not statistically different in the two treatment groups, although those patients in whom postoperative PVR developed tended to have poorer vision (P < 0.0001). There were no differences in complication rates between the two groups.

CONCLUSIONS

There is a significant reduction in the incidence of postoperative PVR in patients receiving the 5-FU and LMWH therapy and in the reoperation rate resulting from PVR. This trial shows that incidence of PVR can be reduced with inexpensive and simple pharmacologic treatment with 5-FU and LMWH and should be used routinely in the treatment of patients at risk of developing PVR.

Prevention of posterior capsule opacification by intraoperative single-dose pharmacologic agents

PURPOSE

To determine whether an intraoperative single dose of dexamethasone, diclofenac, ethylenediaminetetraacetic acid (EDTA), a combination of EDTA and RGD peptide (arginine-glycin-aspartic acid sequence), or mitomycin-C (MMC) is a pharmacological means of preventing or reducing the development of posterior capsule opacification (PCO).

SETTING

Department of Ophthalmology, Celal Bayar University, School of Medicine, Manisa, and Department of Pathology, Dokur Eylül University, School of Medicine, Izmir, Turkey.

METHODS

Fifty-four rabbits were randomly divided into 6 groups. Dexamethasone (4 mg/cc), diclofenac (2.5 mg/cc), EDTA (8 mg/cc), a combination of EDTA and RGD peptide (2.5 mg/cc), or MMC (0.04 mg/cc) was given, 0.1 cc by hydrodissection and 0.9 cc into the capsular bag after phacoemulsification. The sixth group served as a control group. After 3 months, the PCO was graded clinically and the proliferation of lens epithelial cells (LECs) was evaluated histologically.

RESULTS

The drugs were significantly effective in preventing PCO compared with the control (P <.005). Dexamethasone had a weaker effect than the other drugs. In histological analysis, although monolayer LECs in the dexamethasone and diclofenac groups were observed, there was no proliferative activity on the posterior capsules in the EDTA, EDTA+RGD, and MMC groups in contrast to the multilayer cells in the control.

CONCLUSIONS

Intraoperative single-dose application of EDTA, EDTA+RGD peptide combination, and MMC significantly prevented the development of PCO in rabbit eyes. Diclofenac was less effective but also reduced PCO. Although dexamethasone did not prevent the proliferation of LECs, it decreased PCO clinically.

Intravitreal injection of crystalline cortisone as adjunctive treatment of proliferative diabetic retinopathy

PURPOSE

To report the clinical outcome and complications of intravitreal injections of crystalline cortisone in patients undergoing pars plana vitrectomy for treatment of proliferative diabetic retinopathy.

METHODS

The prospective, interventional case series study included 29 consecutive patients (29 eyes) who underwent pars plana vitrectomy for treatment of complicated proliferative diabetic retinopathy associated with central retinal traction detachment. All patients received an intravitreal injection of 15 to 20 mg of crystalline triamcinolone acetonide at the end of surgery, and were operated on by the same surgeon. Mean follow-up time was 1.4 +/- 1.1 months (median, 1 month; range, 0.30 to 4.9 months).

RESULTS

At the end of the follow-up period, the retina was attached in 26 of the 29 patients (89.7%). In three of the 29 patients (10.3%), a retinal redetachment had occurred. None of the patients developed iris neovascularization, and the iris neovascularization, present preoperatively in 12 patients, slightly to markedly regressed in all 12 patients. Preoperative and postoperative intraocular pressure values (P =.72) and blood glucose measurements did not vary significantly. A pseudohypopyon consisting of cortisone crystals in the inferior anterior chamber angle was detected in one patient and resolved spontaneously within 4 days.

CONCLUSIONS

The present clinical study suggests that intravitreal injection of crystalline cortisone with most of the vehicle removed seems to be well tolerated by eyes undergoing pars plana vitrectomy for treatment of complicated diabetic proliferative retinopathy. In view of the antiphlogistic and antiproliferative effect of cortisone, future randomized clinical trials may be indicated to investigate further the role of intravitreal injection of crystalline cortisone in the treatment of proliferative diabetic retinopathy.

Intravitreal injection of crystalline cortisone as adjunctive treatment of proliferative vitreoretinopathy

AIM

To report on clinical outcome and complications of intravitreal injection of crystalline cortisone in patients undergoing pars plana vitrectomy for treatment of proliferative vitreoretinopathy.

METHODS

The study included all 16 patients who underwent pars plana vitrectomy for treatment of proliferative vitreoretinopathy, who received an intravitreal injection of 10-20 mg crystalline triamcinolone acetonide at the end of surgery, and who were operated on by the same surgeon. Most of the vehicle of the solution containing the cortisone crystals was removed before performing the injection. Mean follow up time was 1.64 (SD 2.15) months (median 1. 23 months; range 0.20-9.20 months). The study group was compared with a control group which consisted of 144 patients undergoing pars plana vitrectomy for proliferative vitreoretinopathy performed by the same surgeon.

RESULTS

In the study group compared with the control group, intraocular inflammation, as estimated clinically by slit lamp biomicroscopy, was lower, appearance of the fundus upon ophthalmoscopy in the first postoperative week was clearer, and postoperative pain in the first two postoperative days was reduced. Intraocular pressure measured at the end of the first postoperative week did not vary significantly between the groups. A pseudohypopyon consisting of cortisone crystals in the inferior anterior chamber angle was detected in one patient. Postoperative infectious endophthalmitis was not encountered.

CONCLUSIONS

This pilot study suggests that intravitreal injection of crystalline cortisone with most of the vehicle removed is not toxic to intraocular structures, reduces postoperative intraocular inflammation, and may be a potentially useful additional tool in the treatment of proliferative vitreoretinopathy.

Ciprofloxacin and dexamethasone inhibit the proliferation of human retinal pigment epithelial cells in culture

We investigated the inhibition of proliferation of human retinal pigment epithelial cells in vitro by the 4-quinolone, ciprofloxacin, and the steroid, dexamethasone. The concentration of ciprofloxacin that inhibited growth by 50% (IC50) was found to be 14.1 micrograms/mL. Growth was 100% inhibited at 83 micrograms/mL. At 166 micrograms/mL, all the cells became completely detached and appeared dead at the end of seven days. The IC50 for dexamethasone in RPE cells was found to be 141 micrograms/mL. A dexamethasone concentration of 1.3 mg/mL inhibited proliferation 100% after five days. When the two drugs were combined, the inhibitory effect was found to be additive; i.e., the IC50 dose of the two drugs in combination inhibited RPE cell proliferation by 75%. A combination of the two drugs was also tested for retinal toxicity in rabbit eyes. An examination of histological sections and electroretinograms showed that a dose of 100 micrograms of ciprofloxacin, alone or in combination with 200 micrograms of dexamethasone in saline, was not toxic to the rabbit retina. These studies indicate that a combination of ciprofloxacin and dexamethasone has the potential for reducing the risk of PVR formation and aiding in the prevention of endophthalmitis.

Proliferative vitreoretinopathy--is it anything more than wound healing at the wrong place?

Proliferative vitreoretinopathy (PVR) is a reactive process of the ocular tissue after perforating trauma, retinal detachment, and surgical manipulations. Although several studies, most of them experimental, have focused on the detection of specific etiologic factors in the development of PVR, there is compelling evidence that PVR is nothing more than a physiologic tissue repair process with undesirable consequences for the retina. Important features of PVR involving the role of platelets, mononuclear phagocytes, and fibroblasts parallel the chain of events observed in tissue repair elsewhere in the body. Numerous experimental models for PVR, originally designed to find specific stimuli for the generation of intraocular traction membrane formation, have shown that the process of PVR is the common pathway of the eye's reaction to vitreoretinal trauma of any kind. Accordingly, vitreoretinal surgeons could learn a lot from the work of other disciplines, e.g. surgery and dermatology, on wound healing, and the factors known to modify wound healing elsewhere in the body should be taken into consideration. The well-established impairment of tissue repair processes caused by medical treatment with corticosteroids and cytotoxic agents suggests a combined medical approach to PVR as an adjunct to surgical treatment, using refined methods of application and dosage. Steroids and cytotoxic drugs will influence the course of PVR by suppressing macrophage recruitment and the initial inflammatory reaction as well as the proliferative phase of wound healing with traction retinal detachment, respectively.

Taxol treatment of experimental proliferative vitreoretinopathy

Taxol is a potent stabilizer of microtubules, and inhibitor of in vitro replication, migration, and contraction of fibroblasts. It has been found to limit the development of experimental tractional retinal detachments in nonvitrectomized rabbit eyes. We used taxol in vitrectomized, phakic rabbit eyes with experimentally induced proliferative vitreoretinopathy and tractional retinal detachments. Taxol was dissolved in 30% DMSO because of poor aqueous solubility. A single 0.1 ml intravitreal dose of 2 x 10(-4) M taxol in 30% DMSO was injected immediately after 250,000 heterologous corneal fibroblasts had been injected; 0.1 ml of 30% DMSO was injected into control eyes. Taxol reduced the incidence of tractional retinal detachments seen 3-4 weeks later. When taxol injection was delayed for 3 days after the initial intravitreal injection of fibroblasts into nonvitrectomized eyes, the extent of retinal detachments was reduced, but the incidence of retinal detachment was unchanged from the untreated eyes at the end of 4 weeks. These data indicate that taxol may be most useful when given early in the course of proliferative vitreoretinopathy.

Inflammation and the formation of epiretinal membranes

In this review of the literature evidence is provided from clinical, histological and experimental sources that inflammatory processes play a central role in the pathogenesis of contractile epiretinal membranes and proliferative vitreoretinopathy.

Experimental study on drug therapy of "traction retinal detachment" after posterior penetrating eye injury in the rabbit

In an experimental study on rabbits, a standardized eye injury was created by using the "pars-plana incision model." Subsequently, the effect of intravenous application of dexamethasone and penicillamine on traction retinal detachment was investigated. The two drugs were applied in varying concentrations and combinations (single and combined use in varying intervals), followed by a 3-month control period without medication. Clinical and histological findings showed that intravitreal instillation of 1.2 mg dexamethasone reduces the incidence of retinal detachment from 46% to 27%. Higher concentrations of dexamethasone, as well as the use of penicillamine or a combination of both substances, proved to enhance traction retinal detachment.

Retinal detachment with proliferative vitreoretinopathy: surgical results with scleral buckling, closed vitrectomy, and intravitreous air injection

Seventy-five cases of total retinal detachment complicated by the more advanced grades (grades C and D) of proliferative vitreoretinopathy were treated with scleral buckling, vitrectomy, and air-fluid exchange. The overall reattachment rate was 56%, ranging from 100% in grade C-1 to 26% in grade D-3. The postoperative visual acuity was 6/120 or better in 48% of the 42 eyes in which the retina was reattached. The major causes of surgical failure were redetachment from persistent vitreoretinal traction (32%) and intraoperative complications (12%).

Proliferative vitreoretinopathy and chemotherapeutic agents

Proliferative vitreoretinopathy (PVR) is a disease process that occurs in eyes with rhegmatogenous retinal detachments and accounts for the majority of failures following retinal detachment surgery. PVR involves the uncontrolled proliferation of non-neoplastic cells capable of forming membranes, which may occur on either surface of the retina or along the detached surface of the vitreous gel. Contraction of these membranes creates tractional forces that can distort or detach the retina. Various surgical procedures have been used to repair retinal detachments associated with PVR. The results have not been encouraging in many instances. Recent efforts have been directed toward the chemical inhibition of cellular proliferation in PVR. The majority of drugs used in these studies have been antineoplastic agents that affect various phases in the cycle of cell growth.

Severe proliferative vitreoretinopathy and retinal detachment. I. Initial clinical findings

We studied 716 eyes of 697 patients with retinal detachment associated with the more advanced stages of proliferative vitreoretinopathy (PVR). The factors that influenced the severity of PVR and our criteria for surgical treatment were analyzed using statistical methods. The more severe cases of PVR showed a higher prevalence of cases with (1) retinal detachment exceeding 12 months' duration, (2) no retinal breaks observed, (3) the largest retinal break of a size equal to or exceeding one clock hour, and (4) poor initial visual acuity. Compared with the unoperated group, the eyes on which we subsequently operated were characterized by a greater prevalence of (1) patients with bilateral retinal detachment complicated by PVR, (2) cases with relatively recent onset of retinal detachment, (3) phakic eyes, (4) eyes without vitreous hemorrhage, (5) eyes with one or more visible retinal breaks and with smaller breaks, (6) relatively better initial visual acuity, and (7) less severe degrees of PVR.

Factors influencing final visual results in severely injured eyes

We reviewed 194 consecutive eyes treated by pars plana vitrectomy for severe injury with posterior segment involvement. By using multivariate analysis, we determined which of a large number of clinical, ultrasonographic, and electrophysiologic factors influenced or predicted postoperative visual acuity. Additionally, the effects of the timing of vitrectomy on final vision and the usefulness of prophylactic scleral buckling were analyzed. We found that although clinical data have predictive value, it is electrophysiological information, specifically the visual-evoked potential, which most accurately predicts the postoperative vision of an injured eye. We could not demonstrate a significant effect of the timing of surgery on the final visual result but could determine that prophylactic scleral buckling clearly reduces the rate of delayed retinal detachments.

Intraocular argon laser photocoagulation in the management of severe proliferative vitreoretinopathy

We surgically repaired seven eyes with severe proliferative vitreoretinopathy with intraocular argon laser photocoagulation. Five of the seven retinas were still attached six or more months postoperatively. Endolaser photocoagulation was used in conjunction with pars plana vitrectomy, periretinal membrane stripping, fluid-air exchange, and planned retinotomies. The advantages of endolaser photocoagulation include easier management of posterior retinotomies in an air-filled eye, isolation of anterior traction and retinal breaks by creating an encircling demarcation line posterior to the problem, and less manipulation of existing scleral buckling material.

Effects of cytotoxic drugs on proliferative vitreoretinopathy in the rabbit cell injection model

The effects of adriamycin, 5-fluorouracil, methotrexate, triamcinolone and Viroptic on an experimental model of proliferative vitreoretinopathy (PVR) produced by the injection of homologous dermal fibroblasts into the rabbit vitreous were studied. Adriamycin and fluorouracil inhibited fibroblast proliferation and prevented the formation of membranes as well as did triamcinolone, whereas methotrexate and Viroptic had no beneficial effect in this model of PVR.

Inhibition of experimental intraocular proliferation with intravitreal 5-fluouracil

5-Fluorouracil was used to inhibit experimental intraocular proliferation in rabbit eyes, produced by homologe fibroblast implantation. Two different concentrations were used, 1 and 5 mg in a single intravitreal injection. The eyes were followed up over 4 weeks. Proliferation and resulting traction detachment was reduced from 75% to 30% in the 1-mg 5-fluouracil group. In addition, we observed retinal and vascular changes in a considerable number of eyes treated with 1 mg and much more pronounced alterations in most of the eyes treated with 5 mg fluouracil.

Fluorouracil therapy for proliferative vitreoretinopathy after vitrectomy

Fluorouracil effectively inhibits epiretinal membrane formation and traction retinal detachment after vitrectomy surgery. When 0.5 mg of fluorouracil was administered intraocularly every 24 hours for seven days, traction retinal detachment two weeks after the intraocular injection of 200,000 cultured retinal pigment epithelial cells occurred in 12 of 12 control eyes but in only six of 14 eyes treated with fluorouracil (P less than .001). Four weeks after cell injection, eight of 12 eyes treated with fluorouracil had traction retinal detachments whereas 12 of 12 control eyes did (P less than .001). The height of the traction retinal detachment four weeks after intraocular injection of 200,000 cultured retinal pigment epithelial cells was reduced 50% in eyes treated with 0.5 mg of fluorouracil every 24 hours for seven days compared to control eyes (P less than .001). When the number of injected retinal pigment epithelial cells was increased to 400,000 cells and 1.25 mg of fluorouracil was administered intraocularly every 24 hours for seven days, traction retinal detachment two weeks after injection occurred in 15 of 15 eyes in the control group but in none of ten eyes in the treated group. Four weeks after cell injection, eight of eight eyes in the control group and five of five eyes in the fluorouracil-treated group had detachments and the mean height of the detachments in the two groups was equal. Autoradiography of the epiretinal membranes in eyes injected with 200,000 cultured retinal pigment epithelial cells and labeled for two hours with tritiated thymidine showed that 0.8% of the epiretinal cell nuclei were labeled two weeks after cell injection but that no labeled cells were present in the fluorouracil-treated eyes. Tritiated thymidine labeling of epiretinal cells in the fluorouracil-treated eyes was first noted three weeks after the cell injection. The presence of tritiated thymidine labeling in the fluorouracil-treated eyes correlated with an increase in the number of epiretinal cells and an increase in the incidence of traction retinal detachment.

Control of experimental massive periretinal proliferation by daunomycin: dose-response relation

A condition similar to massive periretinal proliferation in man can be produced in rabbits by injecting homologous fibroblasts into the vitreous. We have studied the effect of daunomycin, a cytotoxic drug, in this model to determine a dose which would not be toxic to the retina but would be effective in preventing proliferation of the injected fibroblasts and eventual retinal detachment. The results of this study demonstrate that daunomycin at a dose of 9 nmol per eye reduces the incidence of retinal detachment by over 50%. Doses higher than 30 nmol per eye are toxic to the retina.

The classification of retinal detachment with proliferative vitreoretinopathy

The term proliferative vitreoretinopathy (PVR) is proposed as a designation for the clinical condition previously known variously as massive vitreous retraction, massive preretinal retraction, or massive periretinal proliferation. This is an abnormality in which rhegmatogenous retinal detachment is complicated by proliferation of membranes on both surfaces of the detached retina and on the posterior surface of the detached vitreous gel. The new classification subdivides PVR into four stages: A, minimal; B, moderate; C, marked; and D, massive. The extent of the fixed retinal folds is subdivided to indicate the number of involved quadrants. The degree of retinal shrinkage into a funnel-like configuration is subdivided into three grades.

X-irradiation in the prevention of experimental post-traumatic vitreous proliferation

We created double perforating injuries in both eyes of 22 rabbits. One eye of each animal was given a dose of 600 Rad x-irradiation 24 hours after the injury. The irradiated eyes developed significantly less intraocular proliferation than the non-irradiated eyes.

The lack of toxicity of intravitreally administered triamcinolone acetonide

We gave one eye of each 21 rabbits an intravitreal injection of 1 mg of triamcinolone acetonide; the other eye received an injection of an equal volume of saline solution as a control. Results of slit-lamp examinations, ophthalmoscopy, intraocular pressure, electroretinography, and light electron microscopy all remained normal throughout the three-month course of the experiment, demonstrating the lack of ocular toxicity of triamcinolone acetonide in the rabbit.

Effect of selected intravitreal drugs after severe penetrating injury in rabbits

The rabbit model of severe double penetrating posterior injury associated with a large vitreous hemorrhage was used to test the efficacy of selected chemotherapeutic agents in preventing vitreal membranes. Intravitreal injection of cytosine arabinoside, doxorubicin, or dexamethasone did not alter the frequency or severity of the resultant vitreal membranes.