T. Stappler

Tamponade efficiency of perfluorohexyloctane and silicone oil solutions in a model eye chamber

Background/aim: As no single tamponade agent yet fulfils all the requirements of a long term inferior tamponade, attempts have been made to mix tamponade materials. This study investigated perfluorohexyloctane (F6H8) and silicone oil solutions designed to take advantage of the high specific gravity and interfacial tension of the F6H8 and the high viscosity of silicone oil. Methods: Solutions of three different densities were examined (1.01, 1.03 and 1.06 g/cm3) inside transparent chambers made of surface modified poly(methylmethacrylate) (PMMA). Results: Compared to F6H8, the solutions had poorer contact with hydrophilic surface of the chambers. The higher the specific gravity of the solution, the better was the contact. The solution with a specific gravity 1.01 g/cm3 is probably of no use clinically. Conclusion: The model eye chamber made of surface modified PMMA is an efficient way of screening and choosing solutions with promising physical properties. Solutions of silicone oil with F6H8 in other proportions or with other semifluorinated alkanes may be of interest.

Does the Presence of an Epiretinal Membrane Alter the Cleavage Plane during Internal Limiting Membrane Peeling

PURPOSE To determine whether the presence of a clinically and/or microscopically detectable epiretinal membrane (ERM) alters the cleavage plane during internal limiting membrane (ILM) peeling. DESIGN Retrospective, observational, immunohistochemical study of ILM specimens using archival formalin-fixed, paraffin-embedded tissue. PARTICIPANTS Fifty-one patients who had had ILM excision. METHODS Fifty-one ILM specimens peeled during vitrectomy for various etiologies were examined by light microscopy. The removal of ILM was assisted using Trypan blue (n = 30), indocyanine green (n = 7), or brilliant blue G (n = 14). Monoclonal antibodies to glial fibrillary acidic protein and to neurofilament protein were used to detect glial or neuronal cells respectively on the vitreous or retinal surfaces of the ILM. Specimens were divided into 2 groups: ILM peeled for full-thickness macular hole (MH; n = 31) and ILM peeled after removal of clinically detectable ERM (n = 20). MAIN OUTCOME MEASURES Primary outcome measure was the localization of immunohistochemical markers to neuronal or glial cells on the vitreous or retinal surfaces of ILM. The secondary outcome measure was the correlation of the results of the primary measure with the dyes used to facilitate ILM peeling. RESULTS Glial and/or neuronal cells were detected on the retinal surface of the ILM in 10 of 31 (32%) of the MH ILM specimens and in 13 of 20 (65%) of the ILM peeled after ERM excision; the difference was significant (P = 0.02). There was no association between the presence of neuronal and glial cells with the type of dye used (P = 0.2). Of the 23 ILM specimens with cells attached to the retinal surface, 21 (91%) were associated with clinical and/or histologic evidence of ERM and 2 (9%) were not. The correlation between the presence of cells on the vitreous and the retinal surfaces of ILM was high (P<0.0001). CONCLUSIONS The findings suggest that ERM may be associated with sub-ILM changes that alter the plane of separation during ILM peeling. This study does not confirm any influence of dyes on the cleavage plane during surgery.

Peel and peel again

Aim: To determine if the internal limiting membrane (ILM) was present in the epiretinal membrane (ERM) when we deliberately tried to perform a “double peel” for macular pucker. Methods: Pars-plana vitrectomy and a “double peel” were carried out. The ERM and ILM were stained with Trypan Blue and peeled separately over the same area. The amount of ERM present in ILM specimens and the amount of ILM present in ERM specimens were evaluated by histological examination. Results: Seventeen eyes in 17 patients were included. It was possible to double peel in all cases. Five of 17 ERM specimens (29%) contained ILM fragments. When ILM was present on the ERM, it represented less than 50% of the sample. One ILM specimen was lost as result of an administrative error; of the remaining 16 specimens, residual ERM was found in six, and cellular remnants were observed on the vitreous surface in a further six of the ILMs. Clinically, no recurrence of ERM was found. Conclusion: ILM was present in some ERM specimens seemingly over the same area that an intact ILM was subsequently peel. We speculate that the ILM in the ERM represent a secondary basement membrane and that the surgical plane of dissection for most ERM peel is between the ERM and the native ILM, making it feasible to double peel routinely.

Intravitreal bevacizumab for retinal vein occlusion and early growth of epiretinal membrane: a possible secondary effect?

Aims To report the early development of epiretinal membranes (ERM) in eyes with retinal vein occlusions (RVO) treated with intravitreal bevacizumab and to describe possible mechanisms that may be involved in the growth and contraction of these lesions. Methods Retrospective and interventional study that included 25 eyes of 25 patients with RVO (16 eyes with central retinal vein occlusion and nine eyes with branch retinal vein occlusion). After an initial 2.5 mg/0.1 ml intravitreal bevacizumab injection all patients were followed-up every 6 weeks. Re-treatments were based on visual acuity and optical coherence tomography findings. Results Twenty-five eyes were treated with bevacizumab and followed for 8.3 (range 4.5–13.5) months. Four eyes developed an ERM within 6–7 weeks after the administration of bevacizumab. ERM was not associated with further deterioration of visual acuity or metamorphopsia in these patients. A rebound of macular oedema was observed in one patient with ERM and in two other patients. No other side effects were observed. Conclusions Intravitreal bevacizumab may be associated with an early growth of ERM in eyes with RVO, although a causative relationship cannot be established. Future randomised clinical trials are necessary to determine the efficacy and safety profile of this novel therapy.

Perception of tilt following counter-rotation surgery

Background:  Macular translocation surgery (MTS) is one of the treatment options for age‐related macular degeneration (AMD) followed by counter‐rotation surgery (CRS) to correct the resulting tilt. The objective of this paper is to determine the perception of tilt following CRS and identify factors that influence the perception of tilt in the presence of residual cyclorotation following CRS.