Experimental microablation of choroidal tissue for autologous retinal pigment epithelium-choroid translocation with the pulsed electron avalanche knife (PEAK-fc).

AIM: To test the microablation of excess graft choroidal tissue with the pulsed electron avalanche knife (PEAK-fc) in an in-vitro model of autologous retinal pigment epithelium (RPE)-choroid translocation. METHODS: Choroidal tissue of porcine RPE-choroid explants was ablated with the PEAK-fc. Tissue morphology was assessed by light microscopy (LM) and scanning electron microscopy (SEM). The amount of ablated choroidal tissue was analysed as a function of three PEAK-fc parameters: (1) amplitude of biphasic voltage (70-100%); (2) distance between choroidal tissue and tip of the PEAK-fc (0-300 µm); and (3) exposure time (2-8 s). RESULTS: LM and SEM showed a smooth plain within the ablation area with well defined cutting edges and preserved adjacent tissue structure. The mean amount of ablated tissue correlated linearly with applied voltage (range 79-120 µm, r=0.34) and distance between choroidal tissue and PEAK-fc tip (range 10-100 µm, r=0.74). The mean amount of ablated tissue increased with exposure time between 2 and 4 s (36-88 µm, r=0.4) and remained constant between 4 and 8 s. CONCLUSION: The PEAK-fc accurately microablates choroidal tissue in-vitro. The adjacent choroidal tissue structure and Bruch's membrane are preserved. Patient studies are required to test the PEAK-fc in RPE-choroid translocation surgery.

Photodynamic therapy with intravitreal application of triamcinolone acetonide in age-related macular degeneration: functional results in 54 patients.

PURPOSE: This study aimed to investigate the functional results, efficacy and complications after photodynamic therapy (PDT) combined with intravitreal triamcinolone acetonide injection (IVTA) in patients with choroidal neovascularization (CNV) caused by age-related macular degeneration (AMD). METHODS: A retrospective analysis of clinical data for 54 patients with CNV resulting from AMD was carried out. All patients had a follow-up of 12 months. The patients were treated with standardized PDT and IVTA (4 mg) as a first-line treatment or following PDT failure. Visual acuity (VA), greatest linear diameter (GLD) of the CNV and foveal thickness were evaluated. RESULTS: Mean VA at baseline was 0.8 logMAR (0.4-1.4). After 12 months VA improved (> 2 lines) in 20.4% of patients and stabilized (+/- 2 lines) in 64.8%. There was no statistical significance in VA outcome between patients undergoing first-line treatment and patients with PDT failure; however, fewer PDT treatments were required to stop CNV activity in patients undergoing first-line treatment. At 12 months, a reduction in foveal thickness was seen in 67.7% of patients and a reduction in CNV GLD in 32.7%. Complications occurred in 22% of patients and included a transient rise in intraocular pressure, cataract and sterile hypopyon. CONCLUSIONS: Our analysis shows that fewer PDT treatments were required to stop CNV activity when triamcinolone was used as first-line treatment. We can thus conclude that PDT combines synergistically with IVTA and the combination may lead to a cost reduction compared with PDT therapy alone. The overall complication rate of 22% is high and must be compared with complication rates caused by new intravitreal anti-VEGF (vascular endothelial growth factor) drugs in combination with PDT.

Autologous retinal pigment epithelium-choroid sheet transplantation in age related macular degeneration: morphological and functional results.

OBJECTIVE: To evaluate the outcome of autologous retinal pigment epithelium (RPE)-choroid sheet transplantation after removal of a subfoveal choroidal neovascularisation (CNV) in patients with age related macular degeneration (AMD). METHODS: RPE-choroid sheet transplantation was performed in 10 consecutive patients with exudative AMD (n = 9) or geographic atrophy (n = 1). After CNV extraction, an autologous RPE-choroid patch was translocated from the midperiphery under the macula. Follow-up was between 6 and 12 months. Visual acuity testing and microperimetry (Nidek-MP1) as well as autofluorescence, fluorescein and indocyanine green (ICG) angiography were performed and the data were analysed retrospectively. RESULTS: Visual acuity (logarithm of minimum angel of resolution) before operation ranged from 0.7 to 1.8 (mean 1.37) and after operation from 0.4 to 1.6 (mean 1.24). Visual acuity after operation improved in seven patients (by a mean of 0.26), remained stable in one patient and decreased in two patients. Microperimetry showed light sensitivity and fixation on the sheet in five cases. ICG angiography demonstrated perfusion through the RPE-choroid graft in nine patients. Postoperative complications included retinal detachment (n = 1) and epiretinal membrane formation (n = 2). The patient with geographic atrophy developed a CNV after surgery. CONCLUSIONS: Autologous RPE-choroid sheet transplantation is feasible and a comparatively safe procedure. Microperimetry showed fixation and light perception over the graft with a moderate increase in mean visual acuity.

Fundus autofluorescence before and after photodynamic therapy for choroidal neovascularization secondary to age-related macular degeneration.

BACKGROUND AND OBJECTIVE: To describe fundus autofluorescence patterns in choroidal neovascularization secondary to age-related macular degeneration before and after photodynamic therapy (PDT). PATIENTS AND METHODS: Sixty-eight consecutive eyes were indicated for PDT after standard fluorescein angiography, which showed completely classic choroidal neovascularization (CNV) (n=52), occult with no classic CNV (n=7), and predominantly classic CNV (n=9). Standardized PDT was performed and patients were examined 2 to 3 months later. Angiography and autofluorescence measurements were performed again and compared with preoperative values. RESULTS: At baseline, autofluorescence was mainly decreased in areas of completely classic CNV (79%), but showed a regular or mottled pattern in occult CNV. A slightly increased (50%) or normal (50%) autofluorescence was seen at the rim of the classic lesions within the junctional zone. Membrane demarcation was improved (90%) in classic membranes 2 to 3 months after PDT. After PDT for occult membranes, a transformation into classic membranes with residual leakage and need for further PDT was observed (6 of 7 eyes), showing the described autofluorescence patterns. For the mixed type of CNV, both described patterns of autofluorescence distribution were found. CONCLUSION: Especially classic CNVs reveal distinct characteristics of significantly decreased autofluorescence, presumably due to their localization above the retinal pigment epithelium level, leading to blockage of autofluorescence. Autofluorescence patterns after PDT included enhanced demarcation of the membrane, suggesting reactive retinal pigment epithelial changes. Autofluorescence might be an interesting tool to distinguish noninvasively between classic and occult CNV in age-related macular degeneration and to monitor changes after PDT.

Pars plana vitrectomy, phacoemulsification and intraocular lens implantation. Comparison of clinical complications in a combined versus two-step surgical approach.

PURPOSE: To report intra-and postoperative complications in pars plana vitrectomy, phacoemulsification and intraocular lens implantation. A comparison of the combined versus two step surgical approach is given. METHOD: Medical records and operative notes of 111 eyes with combined surgery and 50 eyes with sequential surgery were retrospectively analysed. Subgroup analysis was performed to evaluate differences in disease groups, the use of endotamponading or endolaser and cryocoagulation. Postoperative follow-up time was between 3 and 18 months. RESULTS: Combined surgery: 64 eyes (57.5%) showed no complications. 17 eyes (15.3%) showed transient intraocular pressure rise, 17 eyes (15.3%) fibrinous exudation in the anterior chamber. Posterior capsule tears occurred in 7 eyes (6,3%), formation of posterior synechia was observed in 7 eyes (6.3%). IOL dislocation was seen in 3 eyes (2.7%), heavy covering of macrophages in 3 eyes (2,7%). Rare complications included silicon oil efflux into the anterior chamber (1.8%), anterior chamber hemorrhage (1,8%) and iris incarceration into the corneoscleral incision (0,9%). One eye needed explantation of the IOL during the follow-up. Sequential surgery: 31 eyes (62%) showed no complication. Transient intraocular pressure rise occurred in 14 eyes (28%), fibrinous exudation in 2 eyes (4%). Formation of posterior synechia was observed in 1 eye (2%), posterior capsule tears occurred in 4 eyes (8%). Dislocation of the IOL was seen in 1 eye (2%). Subgroup analysis revealed fibrinous exudation in the anterior chamber to be significantly more frequent after combined surgery, particularly in cases of proliferative diabetic retinopathy. CONCLUSION: Combined pars plana vitrectomy, phacoemulsification and intraocular lens implantation as well as the two-step procedure are safe and effective. Sequential surgery could be advantageous to minimize the postoperative anterior chamber inflammatory response.