Perfluorohexylethan (O62) as ocular endotamponade in complex vitreoretinal surgery

Results of different strategies to manage complicated retinal re-detachment

PURPOSE

Complicated retinal re-detachment with inferior proliferative vitreoretinopathy (PVR) remains a challenge. This study's aim was to compare vitrectomy with conventional silicon oil (CSO) combined with an encircling band (EB) and vitrectomy with heavy silicon oil (HSO) alone to treat retinal re-detachment through inferior PVR, where standard procedures have already failed.

METHODS

A retrospective analysis was done on patients with inferior complex re-detachment with secondary PVR after primary surgery, who received pars plana vitrectomy (PPV) with CSO combined with EB (group 1) or PPV alone with HSO (group 2) between December 2006 and August 2017. The primary endpoint was retinal reattachment, and the secondary endpoint was visual acuity (VA) change and complications in both groups.

RESULTS

This study included 119 eyes. Total single surgery anatomical success (SSAS) was 64%, with 80% (52/65) achieved in group 1 and 44.5% (24/54) in group 2 (p < 0.0001). The total final anatomical success (FAS) rate was 79% (94/119). In group 1, FAS was 91% (59/65) compared with 65% (35/54) in group 2 (p = 0.003). The pretreatment VA of group 1 had a median of 1.4 logMAR (95% CI 0.3-1.8), and group 2 showed a median of 1.4 logMAR (95% CI 0.2-1.8). The post-treatment decrease in group 1 was a median equal to - 0.6 versus - 0.1 for group 2 (p = 0.0001). Serious complications were similar in both groups.

CONCLUSION

For complicated retinal re-detachment through inferior PVR, the combination of PPV with EB may lead to better anatomical (SSAS, FAS) and functional success compared with PPV alone with HSO.

Tamponade in surgery for retinal detachment associated with proliferative vitreoretinopathy

BACKGROUND

Retinal detachment (RD) with proliferative vitreoretinopathy (PVR) often requires surgery to restore normal anatomy and to stabilize or improve vision. PVR usually occurs in association with recurrent RD (that is, after initial retinal re-attachment surgery), but occasionally may be associated with primary RD. Either way, for both circumstances a tamponade agent (gas or silicone oil) is needed during surgery to reduce the rate of postoperative recurrent RD.

OBJECTIVES

The objective of this review was to assess the relative safety and effectiveness of various tamponade agents used with surgery for RD complicated by PVR.

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (the Cochrane Library 2019, Issue 1), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to January 2019), Embase (January 1980 to January 2019), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to January 2019), 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 2 January 2019.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) on participants undergoing surgery for RD associated with PVR that compared various tamponade agents.

DATA COLLECTION AND ANALYSIS

Two review authors screened the search results independently. We used the standard methodological procedures expected by Cochrane.

MAIN RESULTS

We identified four RCTs (601 participants) that provided data for the primary and secondary outcomes. Three RCTs provided data on visual acuity, two reported on macular attachment, one on retinal reattachment and another two on adverse events such as RD, worsening visual acuity and intraocular pressure. Study Characteristics Participants' characteristics varied across studies and across intervention groups, with an age range between 21 to 89 years, and were predominantly men. The Silicone Study was conducted in the USA and consisted of two RCTs: (silicone oil versus sulfur hexafluoride (SF₆) gas tamponades; 151 participants) and (silicone oil versus perfluropropane (C₃F₈) gas tamponades; 271 participants). The third RCT compared heavy silicone oil (a mixture of perfluorohexyloctane (F₆H₈) and silicone oil) with standard silicone oil (either 1000 centistokes or 5000 centistokes; 94 participants). The fourth RCT compared 1000 centistokes with 5000 centistokes silicone oil in 85 participants. We assessed most RCTs at low or unclear risk of bias for most 'Risk of bias' domains. Findings Although SF₆ gas was reported to be associated with worse anatomic and visual outcomes than was silicone oil at one year (quantitative data not reported), at two years, silicone oil compared to SF₆ gas showed no evidence of a difference in visual acuity (33% versus 51%; risk ratio (RR) 1.57; 95% confidence interval (CI) 0.93 to 2.66; 1 RCT, 87 participants; low-certainty evidence). At one year, another RCT comparing silicone oil and C₃F₈ gas found no evidence of a difference in visual acuity between the two groups (41% versus 39%; RR 0.97; 95% CI 0.73 to 1.31; 1 RCT, 264 participants; low-certainty evidence). In a third RCT, participants treated with standard silicone oil compared to those receiving heavy silicone oil also showed no evidence of a difference in the change in visual acuity at one year, measured on logMAR scale ( mean difference -0.03 logMAR; 95% CI -0.35 to 0.29; 1 RCT; 93 participants; low-certainty evidence). The fourth RCT with 5000-centistoke and 1000-centistoke comparisons did not report data on visual acuity. For macular attachment, participants treated with silicone oil may probably experience more favorable outcomes than did participants who received SF₆ at both one year (quantitative data not reported) and two years (58% versus 79%; RR 1.37; 95% CI 1.01 to 1.86; 1 RCT; 87 participants; low-certainty evidence). In another RCT, silicone oil compared to C₃F₈ at one year found no evidence of difference in macular attachment (RR 1.00; 95% CI 0.86 to 1.15; 1 RCT, 264 participants; low-certainty evidence). One RCT that compared 5000 centistokes to 1000 centistoke reported that retinal reattachment was successful in 67 participants (78.8%) with first surgery and 79 participants (92.9%) with the second surgery, and no evidence of between-group difference (1 RCT; 85 participants; low-certainty evidence). The fourth RCT that compared standard silicone oil with heavy silicone oil did not report on macular attachment. Adverse events In one RCT (86 participants), those receiving standard 1000 centistoke silicone oil compared with those of the 5000 centistoke silicone oil showed no evidence of a difference in intraocular pressure elevation at 18 months (24% versus 22%; RR 0.90; 95% CI 0.41 to 1.94; low-certainty evidence), visually significant cataract (49% versus 64%; RR 1.30; 95% CI 0.89 to 1.89; low-certainty evidence), and incidence of retina detachment after the removal of silicone oil (RR 0.36 95% CI 0.08 to 1.67; low-certainty evidence). Another RCT that compared standard silicone oil with heavy silicone oil suggests no difference in retinal detachment at one year (25% versus 22%; RR 0.89; 95% CI 0.54 to 1.48; 1 RCT; 186 participants; low-certainty evidence). Retinal detachment was not reported in the RCTs that compared silicone oil versus SF₆ and silicone oil versus to C₃F₈.

AUTHORS' CONCLUSIONS

There do not appear to be any major differences in outcomes between C₃F₈ and silicone oil. Silicone oil may be better than SF₆ for macular attachment and other short-term outcomes. The choice of a tamponade agent should be individualized for each patient. The use of either C₃F₈ or standard silicone oil appears reasonable for most patients with RD associated with PVR. Heavy silicone oil, which is not available for routine clinical use in the USA, may not demonstrate evidence of superiority over standard silicone oil.

[Current importance of heavy fluids as intraoperative aids in vitreoretinal surgery]

A major milestone in the treatment of complex retinal detachment was the development of heavy fluids as intraoperative short-term tamponades. Since the introduction liquid perfluorocarbons and hydrofluorocarbons are particularly noteworthy. Irrespective of the suitability of the substances in principle, the purity during the manufacturing process is a decisive factor that determines possible side effects. Also, the direct exchange with silicone oil can lead to mixing with disadvantageous results. Retinal surgeons should be informed about the properties of the tamponades used. Despite all expectations, the heavy liquids could not become established compared to silicone oil as a long-term tamponade, which is why their domain is the short-term intraoperative use.

Anatomical success rate of pars plana vitrectomy for treatment of complex rhegmatogenous retinal detachment

Background

Pars plana vitrectomy (PPV) is preferred surgical procedure for the management of complex rhegmatogenous retinal detachment (RRD). The purpose of this study was to evaluate the anatomical results of primary PPV for the treatment of primary complex RRD and to determine the influence of lens status, tamponading agent, preoperative proliferative vitreoretinopathy (PVR) and axial length (AL) of the eye upon the anatomical outcome.

Methods

A retrospective consecutive chart analysis was performed on 117 eyes from 117 patients with complex RRD managed with PPV. Fifty-nine eyes were phakic and 58 pseudophakic eyes. All patients had a minimum follow-up period of 12 months. Eyes were classified into groups using independent variables (first classification based upon lens status and tamponade used, second classification based upon lens and PVR status and third classification based upon AL of the eye). The groups were compared for anatomical outcomes (dependent variables) using nonparametric- or, in case of normally distributed data, parametric- statistical tests.

Results

Retinal reattachment rate in phakic eyes was 94.9% compared to 93.1% in pseudophakic, with no statistically significant difference between the two. The overall retinal reattachment rate with single surgery was 94.0%. Final reattachment rate was 97.4%. In case of established PVR ≥ C1, the reattachment rate was not statistically different (92.6%) from eyes with no PVR (91.1%) irrespective of lens status. A statistically significant difference was found between redetachment rates only between phakic eyes with gas tamponade compared to silicon oil (SO) (p = 0.001). Reattachment rate proved to be similar in both AL groups (≤24 mm and > 24 mm).

Conclusions

High anatomical success rate of primary vitrectomy for complex RRD with either gas or SO tamponade was achieved in phakic as well as pseudophakic eyes irrespective of AL of the eye.

Heavy silicone oil and intraocular inflammation

In the past two decades, many advances have been made in vitrectomy instrumentation, surgical techniques, and the use of different tamponade agents. These agents serve close retinal breaks, confine eventual retinal redetachment, and prevent proliferative vitreoretinopathy (PVR). Long-acting gases and silicone oil are effective internal tamponade agents; however, because their specific gravity is lower than that of the vitreous fluid, they may provide adequate support for the superior retina but lack efficacy for the inferior retina, especially when the fill is subtotal. Thus, a specific role may exist for an internal tamponade agent with a higher specific gravity, such as heavy silicone oils (HSOs), Densiron 68, Oxane HD, HWS 45-300, HWS 46-3000, and HeavySil. Some clinical evidence seems to presume that heavy tamponades are more prone to intraocular inflammation than standard silicone if they remain in the eye for several months. In this review, we discuss the fundamental clinical and biochemical/molecular mechanisms involved in the inflammatory response after the use of heavy tamponade: toxicity due to impurities or instability of the agent, direct toxicity and immunogenicity, oil emulsification, and mechanical injury due to gravity. The physical and chemical properties of various HSOs and their efficacy and safety profiles are also described.

Tamponade in surgery for retinal detachment associated with proliferative vitreoretinopathy

BACKGROUND

Retinal detachment (RD) with proliferative vitreoretinopathy (PVR) often requires surgery to restore normal anatomy and to stabilize or improve vision. PVR usually occurs in association with recurrent RD (that is, after initial retinal re-attachment surgery) but occasionally may be associated with primary RD. Either way, a tamponade agent (gas or silicone oil) is needed during surgery to reduce the rate of postoperative recurrent RD.

OBJECTIVES

The objective of this review was to assess the relative safety and effectiveness of various tamponade agents used with surgery for retinal detachment (RD) complicated by proliferative vitreoretinopathy (PVR).

SEARCH METHODS

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2013, Issue 5), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to June 2013), EMBASE (January 1980 to June 2013), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to June 2013), 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 26 June 2013.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) of participants undergoing surgery for RD associated with PVR that compared various tamponade agents.

DATA COLLECTION AND ANALYSIS

Two review authors screened the search results independently. We used the standard methodological procedures expected by The Cochrane Collaboration.

MAIN RESULTS

The review included 516 participants from three RCTs. One study was conducted in the USA and consisted of two trials: the first trial randomized 151 adults to receive either silicone oil or sulfur hexafluoride (SF6) gas tamponades; and the second trial randomized 271 adults to receive either silicone oil or perfluropropane (C3F8) gas tamponades. The third trial was a multi-center international trial and randomized 94 participants (age range not specified) to receive heavy silicone oil (a mixture of perfluorohexyloctane (F6H8) and silicone oil) versus standard silicone oil (either 1000 centistokes or 5000 centistokes, per the surgeon's preference).In participants with RD associated with PVR, outcomes after pars plana vitrectomy and infusion of either silicone oil, perfluropropane gas, or sulfur hexafluoride gas appeared comparable for a broad variety of cases. There were no significant differences between silicone oil and perfluoropropane gas in terms of the proportion of participants achieving at least 5/200 visual acuity (risk ratio (RR) 0.97; 95% confidence interval (CI) 0.73 to 1.31) or achieving macular attachment (RR 1.00; 95% CI 0.86 to 1.15) at a minimum of one year. Although sulfur hexafluoride gas was reported to be associated with significantly worse anatomic and visual outcomes than was silicone oil at one year (quantitative data not reported), there were no significant differences between silicone oil and sulfur hexafluoride gas in terms of achieving at least 5/200 visual acuity at two years (RR 1.57; 95% CI 0.93 to 2.66). For macular attachment, participants treated with silicone oil received significantly more favourable outcomes than did participants who received sulfur hexafluoride at both one year (quantitative data not reported) and two years (RR 1.37; 95% CI 1.01 to 1.86). The first two trials did not perform any sample size calculation or power detection. In the third trial, which had a power of 80% to detect differences, heavy silicone oil was not shown to be superior to standard silicone oil. There were no significant differences between standard silicone oil and heavy silicone oil in the change in visual acuity at one year using adjusted mean logMAR visual acuity (mean difference -0.03 logMAR; 95% CI -0.35 to 0.29). Adverse events were not reported for the first two trials. For the third trial, only the total number of adverse events was reported, and adverse events for each group were not specified. Of the 94 participants, four died, 26 had recurrent retinal detachment, 22 developed glaucoma, four developed a cataract, and two had capsular fibrosis.All three trials employed adequate methods for random sequence generation and allocation concealment. None of the trials employed masking of participants and surgeons, and only the third trial masked outcome assessors. The first trial had a large portion of participants excluded from the final analyses, while the other two trials were at low risk of attrition bias. All trials appear to be free of reporting bias. The first two trials were funded by the National Eye Institute, and the third trial was funded by the German Research Foundation.

AUTHORS' CONCLUSIONS

The use of either perfluropropane or standard silicone oil appears reasonable for most patients with RD associated with PVR. Because there do not appear to be any major differences in outcomes between the two agents, the choice of a tamponade agent should be individualized for each patient. Heavy silicone oil, which is not available for routine clinical use in the USA, has not demonstrated evidence of superiority over standard silicone oil.

Pars plana vitrectomy with medium-term postoperative perfluoro-N-octane for recurrent inferior retinal detachment complicated by advanced proliferative vitreoretinopathy

PURPOSE

To describe a series of patients with recurrent inferior retinal detachment complicated by proliferative vitreoretinopathy (PVR) treated with pars plana vitrectomy and postoperative perfluoro-n-octane (PFO).

METHODS

Consecutive patients with recurrent inferior retinal detachment and Grade C PVR were prospectively treated with 25-gauge pars plana vitrectomy and postoperative "medium-term" PFO for 2- to 3-week duration. All patients had subsequent PFO removal in a planned staged procedure.

RESULTS

Forty-four eyes of 44 patients were included. Mean follow-up time was 30.71 ± 12.92 months. Successful reattachment was achieved in 86% of eyes (38/44). Reattachment rates were statistically equivalent between eyes with and without previous scleral buckle. Reasons for redetachment were recurrent inferior PVR (four of six) and new superior break without PVR (two of six). Additional complications observed were cataract progression requiring surgery (42%), persistent intraocular pressure elevation (36%), and transient inflammation (32%). Macula-off status (P = 0.02) and persistent intraocular pressure elevation (P = 0.02) were factors associated with worse visual outcome.

CONCLUSION

Medium-term PFO was found to be an efficacious technique for operative management of recurrent inferior retinal detachments complicated by Grade C PVR. The method of primary repair (scleral buckle vs. pars plana vitrectomy) did not affect reattachment rates. Transient inflammation and intraocular pressure elevation are potential complications associated with this technique. Persistent intraocular pressure elevation was associated with worse visual outcome.

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.

25-gauge pars plana vitrectomy with medium-term postoperative perfluoro-n-octane tamponade for inferior retinal detachment

BACKGROUND AND OBJECTIVE

To describe a series of patients with inferior retinal detachments managed with primary 25-gauge pars plana vitrectomy (PPV), 2 to 3 weeks of postoperative perfluoro-n-octane (MT-PFO) tamponade, and upright positioning followed by secondary PPV and PFO removal.

PATIENTS AND METHODS

Interventional case series of 157 patients with inferior retinal detachments with and without proliferative vitreoretinopathy. Eyes were treated with 25-gauge PPV, endophotocoagulation, and MT-PFO tamponade. Patients underwent postoperative upright positioning followed by repeat PPV and PFO removal in a planned, staged procedure.

RESULTS

Mean follow-up was 32 ± 4.6 months. Successful reattachment was achieved in 87.5% of 159 eyes. Main initial postoperative complications were persistent intraocular pressure (IOP) elevation in 34% (n = 54), excessive inflammation in 27% (n = 43), and PFO in the anterior chamber in 21% (n = 34). Additional complications occurring after PFO removal included cataract surgery in 16% (n = 22) of initially phakic eyes, redetachment in 13% (n = 21), and need for filtering surgery in 6% (n = 10). Logistic regression analysis revealed macula status (P = .003) and progression to filtering surgery (P = .001) as significant factors predicting visual outcome at 1-year follow-up.

CONCLUSION

MT-PFO tamponade and upright head positioning may be efficacious for inferior retinal detachment repair in patients unable to assume face-down postoperative positioning. Anatomic and visual outcomes are similar to previously described reattachment procedures. A characteristic granulomatous inflammatory reaction presents in some patients, but does not appear to leave long-term visual or anatomic sequelae. Persistent IOP elevation and progression to filtering surgery may occur in a small percentage of patients and portends a worse visual outcome.

Tamponade in surgery for retinal detachment associated with proliferative vitreoretinopathy

BACKGROUND

Retinal detachment (RD) with proliferative vitreoretinopathy (PVR) often requires surgery. During surgery, a tamponade agent is needed to reduce the rate of recurrent retinal detachment.

OBJECTIVES

The objective of this review was to evaluate the benefits and adverse outcomes of surgery with various tamponade agents.

SEARCH STRATEGY

We searched the Cochrane Controlled Register (CENTRAL), MEDLINE, EMBASE, Latin America and Carribbean Health Sciences (LILACS) and the UK Clinical Trials Gateway (UKCTG). There were no language or date restrictions in the search for trials. The electronic databases were last searched on 9 July 2009.

SELECTION CRITERIA

We included randomized clinical trials comparing patients treated with various tamponade agents.

DATA COLLECTION AND ANALYSIS

Two individuals screened the search results independently. One study with two trials was eligible for inclusion in the review.

MAIN RESULTS

One study with two trials was included in the review. The first trial randomized 151 eyes to receive either silicone oil or sulfur hexafluoride (SF(6)) gas tamponades; the second trial randomized 271 eyes to receive either silicone oil or perfluropropane (C(3)F(8)) gas tamponades. In patients with RD associated with PVR, pars plana vitrectomy and infusion of either silicone oil or perfluropropane gas appear comparable for a broad variety of cases. Sulfur hexafluoride gas was associated with worse anatomic and visual outcomes than either silicone oil or perfluropropane gas.

AUTHORS' CONCLUSIONS

The use of either C(3)F(8) or silicone oil appears reasonable for most patients with RD associated with PVR. Because there do not appear to be any major differences in outcomes between the two agents, the choice of a tamponade agent should be individualized for each patient.

Semifluorinated alkanes--primitive surfactants of fascinating properties

Semifluorinated alkanes (SFAs) are diblock molecules, in which two mutually immiscible moieties, namely the hydrocarbon segment and the perfluorinated segment are bound covalently. The presence of two opposing segments within one molecule makes semifluorinated alkanes a very interesting class of compounds, which show a particular behavior both in bulk and at interfaces. Their highly asymmetric structure, arising from the incompatibility of the both constituent parts, results in surface activity of these molecules (so-called primitive surfactants) when dissolved in organic solvents, and allows for the Langmuir monolayer formation if spread at the air/water interface, despite of the absence of any polar group. Since 1984 (when SFAs have been characterized for the first time by Rabolt et al. [Rabolt JF, Russell TP, Twieg RJ. Macromolecules 1984;17:2786]), semifluorinated alkanes have been subjected to many studies. The present article reviews the results obtained so far and covers the aspects of their synthesis, properties in bulk (solutions and solid state) and applications. Special emphasis is put on the Langmuir monolayer properties and self-organization of SFAs on solid substrates.

Heavy tamponade 1: a review of indications, use, and complications

BACKGROUND

Heavier than water intraocular tamponades have several theoretical advantages over conventional tamponades, especially in the treatment of complicated retinal detachments and proliferative viteroretinopathy of the lower fundus periphery. However, initial clinical series of various heavy tamponades have reported significant complication rates. Therefore, heavy tamponades have not found widespread acceptance. Three recently developed heavy silicone oil tamponades, Oxane HD, Densiron 68, and HWS 46-3000, are much better tolerated and presently seem to enter routine clinical practice.

MATERIALS AND METHODS

Literature review of 21 publications on the clinical application of 9 different heavy tamponades (fluorosilicone, C10F18, F6H8, OL62HV, Oxane HD, O62, F6H8-silicone oil mixture, Densiron 68, and HWS 46-3000).

RESULTS

The first generation (fluorinated silicone and perfluorocarbon liquids) and second generation (partially fluorinated alkanes) of heavy tamponades were associated with relatively high complication rates, for example, tamponade emulsification, intraocular inflammation, and rise in intraocular pressure. The complication spectrum of the new generation of heavy silicone oils (Oxane HD, Densiron 68, and HWS 46-3000) seems to be comparable to conventional silicone oil tamponades while providing better support for the inferior retina and the posterior pole.

CONCLUSION

The recently developed heavy silicone oil tamponades are safe and effective tools for the use of complicated retinal detachments of the inferior fundus.

Biocompatibility assessment of liquid artificial vitreous replacements: relevance of in vitro studies

The biocompatibility of liquid artificial vitreous replacements is generally assessed by performing tests in animal models before their clinical use, whereas in vitro experimentation is seldom carried out due to their physico-chemical characteristics. Since their introduction in vitreoretinal surgery, however, the use of some certified vitreous replacements has been discouraged after clinical trials, because of the occurrence of serious side effects. This observation suggests that the tests currently performed for biocompatibility assessment cannot fully guarantee their safety when they are used in humans. Here we review the available literature on in vitro biocompatibility testing of liquid artificial vitreous replacements and survey our own experience on the subject, obtained by using primary retinal cell cultures, seeded on micro-porous inserts. We suggest that in vitro biocompatibility assessment, conducted before experiments in animal models, could improve the required safety evaluation and decrease the risk of undesired side effects, as well as providing a beneficial reduction of animal experimentation.

Anatomical and Functional Results of Endotamponade with Heavy Silicone Oil – Densiron® 68 – in Complicated Retinal Detachment

BACKGROUND

High-density silicone oils are newly developed long-term tamponade agents for the treatment of complicated retinal detachment in the inferior retina. Previous studies describe satisfying anatomical and functional results. In this study we examined the largest cohort so far for a 9-month follow-up and performed a comparison to conventional silicone oil.

METHODS

Our study documents results and adverse effects after vitreoretinal surgery and endotamponade with Densiron 68 in 99 cases of complicated retinal detachment. A 9-month follow-up was performed. Data of 21 patients with intraocular conventional silicone oil tamponade in complicated retinal detachment were retrospectively analyzed and served as control.

RESULTS

Anatomical success was achieved in 78 of 89 eyes (87.6%) with completed follow-up; visual acuity did not change significantly (from mean preoperative logMAR 1.88 to postoperative logMAR 1.96 (p = 0.9). Compared to control a higher anatomical success but a similar number of adverse effects were observed with heavy silicone oil in vitreous. Nevertheless, patients who received Densiron 68 twice due to redetachment showed a significantly higher rate of intraocular inflammation with the tamponade agent in situ.

CONCLUSION

Our results support the hypothesis of Densiron 68 as potent tamponade agent for complicated retinal detachment in the inferior retinal segments especially in eyes where a previous operation failed.

A NEW HEAVY SILICONE OIL (HWS 46-3000) USED AS A PROLONGED INTERNAL TAMPONADE AGENT IN COMPLICATED VITREORETINAL SURGERY

PURPOSE

To report the results of a prospective pilot study using a new heavy agent, HWS 46-3000, as long-term endotamponade in complicated retinal detachment.

METHODS

Thirty-two consecutive patients were enrolled in the study. Indications for enrollment included retinal detachment with proliferative vitreoretinopathy arising from inferior or posterior tears. The patients underwent pars plana vitrectomy, membrane peeling, and HWS 46-3000 filling. Follow-up examinations were scheduled at 1 day to 7 days and 1 month to 3 months after initial surgery and 7 days and 1 month to 6 months after endotamponade removal.

RESULTS

At baseline examination, mean best-corrected Snellen visual acuity was 2.44 logarithm of the minimal angle of resolution (logMAR). HWS 46-3000 was removed after 45 days to 96 days. Initial retinal reattachment was achieved in all eyes. HWS 46-3000 endotamponade was associated with a success rate of 84.6% with a single surgery and an overall success rate of 100% at 6 months with the second operation and conventional silicone oil endotamponade. At 6 months, mean best-corrected visual acuity was +1.09 logMAR (P < 0.0001). Complications were posterior subcapsular cataract formation (100%), membrane formation (3 eyes, 9%), and increased intraocular pressure (1 eye). Emulsification and intraocular inflammation were not observed.

CONCLUSION

HWS 46-3000 was well tolerated, effective in the inferior quadrants with a low incidence of membrane development. The main complication was the high rate of tamponade-related cataract formation.