Publications by authors named "Theodor Stappler"

19 Publications

  • Page 1 of 1

Successful Treatment of Macular Hole-Evoked Retinal Detachment with Inverted ILM Flap following Complicated Cataract Surgery.

Klin Monbl Augenheilkd 2021 Jan 15. Epub 2021 Jan 15.

Department of Ophthalmology, University of Lausanne, Jules Gonin Eye Hospital, Fondation Asile des Aveugles, Lausanne, Switzerland.

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http://dx.doi.org/10.1055/a-1333-3396DOI Listing
January 2021

Rupture of the Globe: What to Do, What not to Do.

Klin Monbl Augenheilkd 2020 Sep 23;237(9):1070-1078. Epub 2020 Sep 23.

Klinik für Augenheilkunde, Charité - Universitätsmedizin Berlin.

Due to their complexity, globe ruptures are highly compromising traumas for the patient. This is due on the one hand to the eye injury itself with the accompanying loss of vision and on the other hand due to the need for extended treatment with uncertain prognosis and the resulting psychological stress. Globe ruptures are among the prognostically most unfavorable injuries due to the force and peak pressure impacting the eye. Furthermore, contusional retinal necrosis may be of significance prognostically. In the present review, we discuss treatment of globe ruptures involving retinal surgery. We discuss the primary sugery, its chronological planning and extent as well as the necessity for follow-up interventions. We also discuss the origin of traumatic retinal detachment with differential diagnosis of giant retinal tear versus oradialysis as well as secondary sequelae of traumas such as formation of macular holes and their treatment. On this basis, the use of buckling surgery versus pars-plana vitrectomy is discussed. Further focus is set on the role of the iris lens diaphragm in surgery of globe ruptures.
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http://dx.doi.org/10.1055/a-1233-8997DOI Listing
September 2020

OCRIPLASMIN FOR VITREOMACULAR TRACTION IN CLINICAL PRACTICE: The INJECT Study.

Retina 2021 Feb;41(2):266-276

Oxurion NV, Leuven, Belgium.

Purpose: Randomized clinical trials have demonstrated the safety and efficacy of ocriplasmin in patients with vitreomacular traction (VMT), including those with macular hole (MH). The INJECT study prospectively evaluated ocriplasmin in the setting of clinical practice.

Methods: INJECT was a Phase 4, multicenter, prospective observational study. Patients were followed up for 12 months. Assessments included nonsurgical VMT resolution, nonsurgical MH closure, best-corrected visual acuity, occurrence of vitrectomy, and adverse events.

Results: The efficacy population (N = 395) received an ocriplasmin injection and had optical coherence tomography-confirmed VMT at baseline. At Day 28, the rate of nonsurgical VMT resolution was 40.7% in the overall group, and the rate of nonsurgical MH closure was 36.0% in the VMT with MH group. At Month 12, the rate of ≥2-line best-corrected visual acuity gain (irrespective of vitrectomy) was 36.8% in the overall group and 59.6% in the VMT with MH group. The percentage of patients who underwent vitrectomy in the study eye was 29.1% in the overall group and 55.6% in the VMT with MH group. Photopsia (9.8%) and vitreous floaters (6.8%) were the most frequent adverse events.

Conclusion: The INJECT study showed that ocriplasmin is effective in a clinical setting in patients with VMT, with or without MH. No new safety signals were identified from this large and surgeon-selected patient group, although the significant limitations of the study design without an image reading center and scheduled study visit timings should be noted.
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http://dx.doi.org/10.1097/IAE.0000000000002862DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7819525PMC
February 2021

Histopathological Changes and Clinical Outcomes following Intervention for Sub-Internal Limiting Membrane Haemorrhage.

Ophthalmologica 2020 19;243(3):217-223. Epub 2019 Nov 19.

St Pauls Eye Unit, Royal Liverpool Hospital, Liverpool, United Kingdom.

Introduction: Haemorrhage confined to the sub-internal limiting membrane (ILM) space can be associated with good visual recovery. There is controversy as to the best management of purely sub-ILM haemorrhage, which ranges from observation to immediate surgical intervention.

Methods: We studied a retrospective case series of patients with sub-ILM haemorrhage who underwent vitrectomy with subsequent histological analysis of the removed ILM.

Results: Sixteen patients underwent vitrectomy for sub-ILM haemorrhage. Five patients had underlying Terson syndrome, 6 had ruptured macro-aneurysms, and 5 had Valsalva retinopathy. Seven patients demonstrated cellular proliferation on the retinal surface of the ILM with staining for glial fibrillary acidic protein and cytokeratin 7, as well as CD68pg and Prussian blue. All but 1 of these cases were isolated from patients undergoing surgery >4 weeks following initial symptoms, the other presented at >2 weeks. Serial optical coherence tomography (OCT) was available in 8 patients; serial OCT in patients with delayed intervention demonstrated persistent inner retinal layer hyper-reflectance. Fourteen of 15 patients demonstrated symptomatic recovery and showed visual improvement with acuity ranging from -0.1 to 1.8 (mean 0.43) within 3 months of intervention (1 was lost to follow-up). The post-operative vision was 0.11 logMAR (mean; range -0.1 to 0.4) at 3 months in the group with intervention within 2 weeks of symptoms, and 0.9 logMAR (mean; range 0.0 to HM) in the group with delayed surgery.

Conclusions: Early surgical intervention for sub-ILM haemorrhage resulted in good visual outcomes; delayed surgery may lead to proliferative vitreoretinopathy-like changes on the inner retinal surface of the ILM, and untreated cases may demonstrate persistent inner retinal changes potentially limiting visual prognosis despite subsequent surgical intervention.
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http://dx.doi.org/10.1159/000502442DOI Listing
March 2021

Cutting the Internal Limiting Membrane With Zero Aspiration Technique: A Clinical Audit.

Retina 2019 Oct;39 Suppl 1:S133-S136

Royal Liverpool University Hospital, Liverpool, United Kingdom.

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http://dx.doi.org/10.1097/IAE.0000000000001641DOI Listing
October 2019

Polydimethyl Siloxane as an Internal Tamponade for Vitreoretinal Surgery.

Ophthalmologica 2017 19;238(1-2):68-73. Epub 2017 Apr 19.

St Paul's Eye Unit, Royal Liverpool Hospital, Liverpool, UK.

Purpose: To report the efficacy and safety of polydimethyl siloxane (Siluron Xtra®) as an internal tamponade.

Design: Audit and adverse event screening of procedures (March 2014-2015).

Methods: Patients who had undergone vitreoretinal procedures with Siluron Xtra® tamponade were retrospectively analysed with respect to anatomical outcome, visual outcomes, and perioperative complications, in particular intraocular pressure.

Inclusion Criteria: all patients who had undergone Siluron Xtra® tamponade.

Exclusion Criteria: No cases were excluded; however, there were no paediatric or pregnant patients within this cohort. All vitreoretinal cases were included, including retinal detachments, but also trauma, endophthalmitis, and intraocular foreign bodies.

Results: Twenty-eight patients had polydimethyl siloxane as an intraocular tamponade; 24 retinal detachments (83% complicated by proliferative vitreoretinopathy ≥grade C), 12 had previous failed surgery, and 4 had procedures for intraocular lymphoma, endophthalmitis, or trauma. Follow-up was 14-20 months, and mean duration of tamponade was 6.8 months (3-12 months). Anatomical success was 79% after polydimethyl siloxane injection, 58% 3 months following removal (14/24), 5 remain with long-term tamponade, and 5 with redetachment under tamponade required further intervention. Five required topical anti-glaucomatous agents, and 1 following trauma required glaucoma surgery. Cataract developed in 3/6 phakic patients, and visible emulsification occurred in a single patient.

Conclusion: Polydimethyl siloxane seems to be an acceptable alternative tamponade agent for the management of complex retinal detachments with comparable anatomical success and comparable rates of raised intraocular pressure to other low-viscosity silicone oil agents, but more importantly, with a lower rate of emulsified oil-related complications, which is important particularly for cases requiring long-term tamponade.
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http://dx.doi.org/10.1159/000470850DOI Listing
September 2017

Novel heavy tamponade for vitreoretinal surgery.

Invest Ophthalmol Vis Sci 2013 Nov 5;54(12):7284-92. Epub 2013 Nov 5.

Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom.

Purpose: The aim of this study was to produce a heavy tamponade with a specific gravity greater than 1.06 g/mL that was optically transparent, could be manufactured using simple processing, could be injected using standard clinical equipment, and would have appropriate biocompatibility.

Methods: Aerosil silica was added to a phenyl trimethicone and mixed via a roller, overhead stirring, and ultrasonics. The refractive index, visible absorbance, and shear viscosity were measured. The injectability of the solutions was evaluated using the Accurus Viscous Fluid Injection system. The tamponade efficiency was assessed using a model eye chamber and compared with that of Densiron 68, Oxane HD, and F6H8. The biocompatibility was evaluated in vitro and in vivo in rabbits.

Results: Tamponade agents were produced with specific gravities of 1.10, 1.11, 1.13, and 1.16 g/mL that had good optical clarity. Mixing using overhead stirring was sufficient to produce tamponade agents with shear viscosities in the range 1000 to 5000 mPa·s that were reproducible and stable during storage. The solutions were easier to inject using the Accurus Viscous Fluid Injection system than silicone oil 1000 mPa·s. The 11% silica solution had greater tamponade efficiency than Densiron 68 or Oxane HD. There was no evidence of cytotoxicity in vitro. Silica solution 11% induced cataract earlier than Polydimethylsiloxane 1000 (PDMS 1000). Silica solution 11% and phenyl trimethicone reduced the a-wave value at 1 week after vitrectomy, but recovery was observed at later time points. Silica solution 11% caused inner nuclear layer (INL) nuclei dropdown in inferior retina from 4 weeks postoperation. Polydimethylsiloxane 1000 induced a similar phenomenon in superior retina 12 weeks postoperation.

Conclusions: We have produced a heavy tamponade with good clarity that has appropriate shear viscosity, injectibility, enhanced tamponade efficiency, and biocompatibility similar to that of PDMS 1000.
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http://dx.doi.org/10.1167/iovs.13-11876DOI Listing
November 2013

Retrospective review of 50 eyes with long-term silicone oil tamponade for more than 12 months.

Graefes Arch Clin Exp Ophthalmol 2012 May 4;250(5):645-52. Epub 2011 Dec 4.

St Paul's Eye Unit, Royal Liverpool University Hospital, Link 8z, Prescot Street, Liverpool, L7 8XP, UK.

Background: Silicone oil (SO) is an established tamponade in treating complex vitreoretinal diseases. Although SO is intended to be removed after several weeks to months, permanent SO might be unavoidable in a small subgroup of patients with an extremely complicated clinical course. The aim of this study is to describe the long-term effects of intraocular SO tamponade.

Methods: This retrospective study included 50 patients with intraocular SO (Oxane 5700 Bausch & Lomb, Kingston-upon-Thames, UK) for at least 12 months. The most common reasons for long-term SO tamponade were: retinal re-detachment (re-RD), proliferative diabetic retinopathy (PDR), ocular trauma, and persistent hypotony.

Results: Mean age was 59.2 ± 18.4 years, and mean duration of silicone oil in the eye was 54.5 ± 58.6 months (median, 30 months). The average number of previous surgeries were 2.2 ± 1.5. Anatomic success was achieved in 37/50 (74%) of patients. Visual acuities (logMAR) were 1.8 ± 0.6, 1.6 ± 0.6, 2 ± 0.7 and intraocular pressures (mmHg) were 15.6 ± 7, 15.7 ± 5.5, 16.5 ± 7.1 at 3 months, 1 year and at last follow-up respectively. The main long-term silicone-oil-related complications observed were: band keratopathy (8%), corneal decompensation (12%), iris rubeosis (14%), and optic neuropathy (28%). Forty percent of patients achieved ambulatory vision in the SO-filled eye at final follow-up.

Conclusion: Long-term silicone oil can be a last-resort option in selected patients with severe vitreoretinal disease. Anterior and posterior segment complications did occur at significant rates. Forty percent of our patients maintained ambulatory vision. The actual number of patients that achieved satisfactory stereopsis and benefited functionally from long-term SO was much less [7/50 (14%)].
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http://dx.doi.org/10.1007/s00417-011-1873-8DOI Listing
May 2012

Endophthalmitis following intravitreal injections.

Graefes Arch Clin Exp Ophthalmol 2012 Apr 3;250(4):499-505. Epub 2011 Nov 3.

Link 8z, St Paul's Eye Unit, Royal Liverpool University Hospital, Prescot Street, Liverpool, L7 8XP, UK.

Background: To report the clinical features, culture results, management and visual outcome of patients with endophthalmitis following intravitreal injections.

Methods: Retrospective review of all patients with suspected endophthalmitis after intravitreal injections treated with intravitreal antibiotics (teicoplanin and ciprofloxacin) at a referral centre between January 2003 and December 2010.

Results: Nineteen cases that had aqueous or vitreous biopsy were identified. Nine had negative culture. Ten had positive culture; Staphylococcus species in 4/10, Streptococcus species in 4/10, E. coli in 1/10 and gram-negative bacilli in 1/10. Symptoms developed within the first 48 hours in all. One of ten culture-positive cases had no pain on presentation, while 5/9 patients with negative culture reported pain. Initial treatment consisted of intravitreal antibiotics in all cases, 6/19 cases required a second intravitreal antibiotic injection, 4/19 underwent vitrectomy as secondary therapy. At the last follow up, 7/19 patients had visual acuity of 6/18 or better, 9/19 had visual acuity of 6/60 or worse.

Conclusion: The overall numbers of patients with endophthalmitis following intravitreal injections has risen dramatically over the past years. In contrast to earlier reports of multicentre studies, outcome of patients is relatively poor in the current treatment settings. We did not find clinical features useful in identifying cases with negative culture.
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http://dx.doi.org/10.1007/s00417-011-1851-1DOI Listing
April 2012

The effect of scleral exoplant removal on strabismus following retinal detachment repair.

J AAPOS 2011 Aug;15(4):331-3

St. Paul's Eye Unit, Royal Liverpool University Hospital, Liverpool, United Kingdom.

Purpose: Scleral buckling for retinal detachment is a well-reported cause of secondary strabismus. We analyzed the effects on motility of removal of the exoplant alone to determine whether this is warranted as a separate step in the surgical management of these patients.

Methods: A retrospective case series of patients who underwent scleral exoplant removal due to symptomatic strabismus development following retinal detachment repair from 2007 to 2009 was conducted. Manifest horizontal and vertical deviations were treated as vectors of a single combined deviation (|dev|). Pre- and postoperative manifest |dev| in the primary position (|dev|(pp)) and in the gaze position of maximal deviation (|dev|(max)) were analyzed.

Results: Five patients were identified, all with symptomatic, binocular diplopia in the primary position prior to exoplant removal. Median |dev|(pp) prior to exoplant removal was 21(Δ) and following removal was 21(Δ) (P = 0.81). The median |dev|(max) prior to exoplant removal was 33(Δ) and following removal, 22(Δ) (P = 0.82). Median follow-up was 8 months. There were no cases of retinal redetachment following the exoplant removal. No patient reported any subjective improvement of their diplopia. All 5 patients went on to have strabismus surgery as a separate procedure.

Conclusions: Median primary position deviation was unchanged by scleral buckle removal, and Exoplant removal has minimal long-term benefit on the strabismus following scleral buckling procedures.
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http://dx.doi.org/10.1016/j.jaapos.2011.03.016DOI Listing
August 2011

Is there a role for long-term silicone oil tamponade for more than twelve months in vitreoretinal surgery?

Ophthalmologica 2011 22;226 Suppl 1:36-41. Epub 2011 Jul 22.

St Paul's Eye Unit, Royal Liverpool University Hospital, Liverpool, UK.

Despite modern and sophisticated vitreoretinal techniques, the authors are convinced that an underreported patient group exists, for whom long-term silicone oil tamponade is unavoidable. We conducted a literature review of the current evidence base in order to provide guidance on the ocular tolerance and side effects of long-term silicone oil, weighing up benefits against complications as well as providing an outlook on future silicone oils with improved physical properties. We advocate the removal of silicone oil in all cases; however, one has to recognise that long-term silicone oil tamponade may have to be considered as a measure of last resort for selected patients. There is a clinical need to develop novel, emulsification-resistant tamponades.
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http://dx.doi.org/10.1159/000328208DOI Listing
September 2011

Outcomes of delayed vitrectomy in open-globe injuries in young patients.

Retina 2011 Sep;31(8):1541-4

Vitreoretinal Service, St. Paul's Eye Department, Royal Liverpool University Hospital, Liverpool, UK.

Purpose: The timing of vitrectomy for severe penetrating eye injury to the posterior segment remains controversial; this is particularly pertinent if patients are children and young adults. We present our results of the surgical procedure in young patients after penetrating eye injury using a delayed approach.

Methods: Noncomparative interventional study of patients up to 29 years of age who had vitreoretinal surgery for penetrating eye injury. Surgical procedure was performed in seven eyes of six patients. Posterior vitrectomy was performed because of hemophthalmos after waiting for a mean of 49 days (range, 17-90 days) after posterior vitreous detachment was confirmed on ultrasound examination.

Results: The mean postoperative follow-up period was 22 months (range, 9-35 months). Of the 7 patients, 6 (85.7%) achieved visual acuity (Snellen acuity) of 6/12 or better and 4 eyes (57.1%) reached 6/6. At the last follow-up, all patients were pseudophakic, 2 required secondary lens implants, and retinal detachment developed in 1 patient.

Conclusion: This consecutive case series underlines the fact that a delayed approach is compatible with good visual prognosis in relatively young patients.
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http://dx.doi.org/10.1097/IAE.0b013e31820840efDOI Listing
September 2011

The impact of axial length on retinal tamponade for gas, silicone oil, and heavy silicone oil, using an in vitro model.

Graefes Arch Clin Exp Ophthalmol 2011 May 30;249(5):671-5. Epub 2010 Dec 30.

Manchester Royal Eye Hospital, Manchester, M13 9WH, UK.

Background: To investigate whether ocular axial length influences the tamponade efficacy of three commonly used agents: gas, silicone oil, and heavy silicone oil.

Methods: A series of filling experiments was conducted using 19-mm and 25-mm surface-modified spherical model eye chambers to mimic the vitreous cavity. For each agent, tamponade efficacy was assessed across a range of percentage fills, and comparison was made between the two model eye chambers. The behavior of each tamponade agent was quantified by measuring (1) the maximum height of the tamponade bubble, and calculating (2) the arc of retinal contact subtended by the tamponade bubble.

Results: Polynomial regression analysis found no statistically significant difference between the regression models for the different-sized model eye chambers for bubble height or arc of retinal contact subtended. This applied to all of the tamponade agents under investigation.

Conclusions: Across the range of cavity sizes under investigation, no significant difference in tamponade efficacy (as reflected by the measured dimensions of the tamponade bubble) was identified.
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http://dx.doi.org/10.1007/s00417-010-1579-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3084431PMC
May 2011

Fibrous membranes in diabetic retinopathy and bevacizumab.

Retina 2010 Jul-Aug;30(7):1012-6

Unit of Ophthalmology, School of Clinical Sciences, University of Liverpool, Liverpool, UK.

Purpose: The purpose of this study was to determine the histopathologic characteristics of bevacizumab-treated human proliferative diabetic retinopathy (PDR) membranes with particular regard to membrane vasculature as a step toward addressing the effects of the drug on PDR membranes. Intravitreous injection of bevacizumab, an antivascular endothelial growth factor monoclonal antibody, has recently been advocated as an adjunct in surgery for PDR. In this context, a clinically observed decrease in PDR epiretinal membrane vascularity (vascular regression) occurs from 24 hours to 48 hours after injection, but the exact mechanisms of drug action are unknown.

Methods: A consecutive series of seven PDR membrane specimens that had been removed sequentially from seven bevacizumab-treated patients were studied retrospectively. The membrane specimens were examined using light microscopic methods, including immunohistochemistry.

Results: Five of the seven membranes were clinically avascular (one contained "ghost" vessels) and did not hemorrhage during excision. Of these 5 specimens, which included 1 removed 7 days after a total of 6 intravitreous injections of 1.25 mg bevacizumab, 4 contained histologically detectable capillaries (1 did not). These blood vessels were lined by endothelial cells as determined by immunohistochemistry for the endothelial markers CD31 and CD34. The two remaining membranes were clinically and histologically still vascularized despite bevacizumab treatment. All the specimens also contained smooth muscle actin-containing fibroblastic cells within the collagenous stroma.

Conclusion: The findings do not support the concept that the clinical phenomenon of vascular regression in PDR membranes after bevacizumab injection in the vitreous is resulting from obliteration of the membrane blood vessels. Another mechanism appears to be involved in at least some patients, possibly a vasoconstrictive response. Such a mechanism might explain reversal of the effects of bevacizumab that has been reported after this treatment.
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http://dx.doi.org/10.1097/IAE.0b013e3181cb463aDOI Listing
September 2010

F4H5: a novel substance for the removal of silicone oil from intraocular lenses.

Br J Ophthalmol 2010 Mar 14;94(3):364-7. Epub 2009 Oct 14.

St Paul's Eye Unit, Royal Liverpool University Hospital, Liverpool, UK.

Aim: Adherent silicone oil on intraocular lenses (IOLs) following retinal detachment surgery induces large and irregular refractive errors and multiple images, and gives rise to glare, distorted and often poor vision. Its removal remains challenging, often requiring mechanical wiping or explantation. F4H5 is a new semifluorinated alkane into which silicone oil is readily soluble. The aim is to establish the effectiveness of F4H5 in removing silicone oil from three different types of IOL in vitro.

Method: Silicone lenses (Tecnis ZM900, Advanced Medical Optics, Inc.), hydrophobic acrylic lenses (MA60, Alcon Laboratories, Inc.) and PMMA lenses (Ocular Vision, Inc) were first immersed in phosphate-buffered saline, second in silicone oil, then in F4H5 (Fluoron GmbH) for 10 min and lastly vigorously agitated in F4H5 for 1 min. They were weighed at each stage using scales accurate to 0.0001 g to measure the weight of the adherent oil. Dynamic contact angle (DCA) analysis was used to assess their surface properties.

Results: Immersion in F4H5 alone removed 96.1% (+/-1.23) by weight of silicone oil from the hydrophobic acrylic lenses, 91.4% (+/-1.58) from the silicone and 95.6% (+/-1.44) from the PMMA IOLs. Immersion combined with 1 min of agitation increased the removal to 98.8% (+/-0.46) from the acrylic IOLs, to 93.7% (+/-0.48) from the silicone IOLs and to 100% (within +/-0.0001 g) from every PMMA IOL. After treatment with F4H5, all IOL were optically clear. DCA hysteresis curves remained permanently altered. All measurements were highly reproducible.

Conclusion: F4H5 was highly effective at removing the bulk of the silicone oil from all three groups of IOL. The DCA measurements suggested that their surface properties were permanently modified.
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http://dx.doi.org/10.1136/bjo.2009.161489DOI Listing
March 2010

What pressure is exerted on the retina by heavy tamponade agents?

Graefes Arch Clin Exp Ophthalmol 2005 May 17;243(5):474-7. Epub 2004 Nov 17.

St Paul's Eye Unit, Royal Liverpool University Hospital, Liverpool, UK.

Background: Histological changes in the retina during the use of heavy tamponade agents have been linked with the pressure on the retina caused by the increased specific gravity of the agent. This paper calculates the possible increases in pressure due to these agents and questions the validity of this argument.

Methods: A model eye chamber was used to make measurements of the shape of F6H8 bubbles, with incrementally increasing volumes, and thus calculate the maximum possible increase in pressure under the tamponade agent.

Results: The maximum increase in pressure under an F6H8 tamponade which completely fills an eye with a diameter of 2.2 cm would be 0.52 mmHg.

Conclusions: This increase in pressure is within normal diurnal pressure changes in the eye; therefore, it would seem unlikely that such an increase could cause the histological changes observed. With increasing volumes of a heavy tamponade agent, aqueous is excluded from a greater area of retina. This could account for the pathological changes reported.
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http://dx.doi.org/10.1007/s00417-004-1047-zDOI Listing
May 2005

Tamponade properties of double-filling with perfluorohexyloctane and silicone oil in a model eye chamber.

Graefes Arch Clin Exp Ophthalmol 2004 Mar 18;242(3):250-4. Epub 2003 Dec 18.

St Paul's Eye Unit, Royal Liverpool University Hospital, Prescot St., Liverpool, L7 8XP, UK.

Background: The use of perfluorohexyloctane as a heavier-than-water tamponade for long-term use is limited by its tendency to dispersion and associated intraocular inflammation. Double-filling with silicone oil and F6H8 produces a united, two-layer bubble, appearing as a single bubble. This has been proposed as a method of improving the utility of F6H8 as a tamponade.

Methods: A surface modified polymethylmethacrylate model eye chamber was double-filled with perfluorohexyloctane and silicone oil to approximate a 90% fill. The proportion of silicone oil was increased in a stepwise fashion. A qualitative comparison of surface contact at each stage was made. Chambers with one, two or no indent were used. Dispersion by agitation of the chamber was assessed.

Results: With less than 20% silicone oil it was difficult to force the two liquids to make contact. With more oil they united in the form of a single bubble joined at an interface. Once joined, the sides of the single bubble were drawn away from the wall of the chamber. As the proportion of silicone oil increased the area of lost contact increased and progressed inferiorly. Compared to F6H8 alone the double-fill reduced dispersion.

Conclusion: Silicone oil and F6H8 can unite to form a single bubble that changes the effectiveness of either tamponade agent on their own. The double-fill needs to have enough silicone oil to form a single bubble, but this needs to be kept as low as possible to avoid progressive loss of lateral tamponade. It does not provide good simultaneous superior and inferior tamponade. The double-fill reduces dispersion.
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http://dx.doi.org/10.1007/s00417-003-0830-6DOI Listing
March 2004