Pressure dependent direct transtissue transmission of eyewall, sclera and vitreous body in the range of 350-1050nm.

PURPOSE: For transscleral application of optical radiation or light to the eye, it is important to know the transmission and absorbance of the tissue layers of the eyewall. The impact of photochemical energy to the retina located directly at the point of contact with the radiation emitter must be considered as well as the absorbance in choroid and retina. Therefore, the direct transmission of ex vivo porcine eyewalls and vitreous body were measured in this study. METHODS: At ex vivo porcine eyes (N=221) pressure dependent transmission measurements were performed with a pressure inducing setup. Pressure and wavelength dependent direct transmission of eyewall and vitreous body of porcine eyes were described for different applied pressures (23mmHg, 78mmHg and 132mmHg). The transmissions were investigated within the spectral range of 350-1050nm. In addition to the complete eyewall transmission measurements, the transmission of sclera, vitreous body and water was measured individually and the transmission of retina and choroid was calculated. RESULTS: With increasing wavelength and pressure, a significant transmission increase of the eyewall could be achieved (p<0.05). At 400nm and 132mmHg the transmission raised to 0.10%. At 1050nm it increased up to a value of 12.22%. In the visible spectrum, the direct transmission was always below 3.17%. The differences in eyewall transmission of eyes with different iris colors were significant at low pressure. With increasing pressure, the effect strength decreased and the differences lost their significance. CONCLUSIONS: The pressure and wavelength dependent direct transmission of the eyewall and the vitreous body significantly increased with increasing pressure. This results are benefical for technical and clinical safety, research and development of illumination devices. It is necessary to know the intraocular brightness in the eye during diaphanoscopy, photocoagulation application to determine hazards.

Unusual Primary Ocular Manifestation of Sarcoidosis.

A 23-year-old male patient presented with very mild visual disturbances, but a distinct prominence of the optic discs, more pronounced in the right than in the left eye. The ophthalmic symptoms initially seemed trivial, but a large-scale interdisciplinary workup later identified them as the presenting symptoms of sarcoidosis affecting lung and eyes. A standard steroid monotherapy successfully caused regression of the ophthalmic findings.

Short-Term Intraocular Pressure Rise during Locally Induced Force by Ophthalmologic Surgery Applications.

PURPOSE: Surgical or diagnostic procedures are often accompanied by a short-term increase in intraocular pressure (IOP). A short-term increase in IOP can occur during refractive procedures, vitreoretinal surgery, transillumination, photocoagulation, or cryocoagulation. A porcine eye model was chosen (n = 89) to compile comparable study data and to de termine correlations between the force induced and the resulting intraocular pressure while excluding the effect of surgeons. METHODS: The IOP was measured in the anterior chamber. IOP changes were induced by applying an external force and measured when using a cannula, trocar, and cryocoagulation (n = 32), and correlations between force and resulting IOP were assessed (n = 57). RESULTS: A correlation was noted between the force induced and the IOP increase, which showed a linear dependency. The insertion of a 29-G cannula caused a mean ΔIOP value of 49.1 ± 2.9 mm Hg and an external force of 0.76 N, and that of a 23-G trocar 344.4 ± 5.9 mm Hg and 6.09 N, respectively. The rise in IOP during a simulated cryocoagulation reached values between 57.3 ± 14.8 mm Hg (cryoprobe tip diameter: 0.9 mm) and 130.3 ± 2.9 mm Hg (cryoprobe tip diameter: 7.0 mm). CONCLUSION: The values of the forces applied can be converted into the resulting IOP based on the specific action. Surgical or diagnostic procedures should, therefore, be evaluated with regard to preexisting pathologies, such as glaucoma.

Proteomic Analysis of Vitreous Humor in Retinal Vein Occlusion.

PURPOSE: To analyze the protein profile of human vitreous of untreated patients with retinal vein occlusion (RVO). METHODS: Sixty-eight vitreous humor (VH) samples (44 from patients with treatment naïve RVO, 24 controls with idiopathic floaters) were analyzed in this clinical-experimental study using capillary electrophoresis coupled to mass spectrometer and tandem mass spectrometry. To define potential candidate protein markers of RVO, proteomic analysis was performed on RVO patients (n = 30) and compared with controls (n = 16). To determine validity of potential biomarker candidates in RVO, receiver operating characteristic (ROC) was performed by using proteome data of independent RVO (n = 14) and control samples (n = 8). RESULTS: Ninety-four different proteins (736 tryptic peptides) could be identified. Sixteen proteins were found to be significant when comparing RVO and control samples (P = 1.43E-05 to 4.48E-02). Five proteins (Clusterin, Complement C3, Ig lambda-like polypeptide 5 (IGLL5), Opticin and Vitronectin), remained significant after using correction for multiple testing. These five proteins were also detected significant when comparing subgroups of RVO (central RVO, hemi-central RVO, branch RVO) to controls. Using independent samples ROC-Area under the curve was determined proving the validity of the results: Clusterin 0.884, Complement C3 0.955, IGLL5 1.000, Opticin 0.741, Vitronectin 0.786. In addition, validation through ELISA measurements was performed. CONCLUSION: The results of the study reveal that the proteomic composition of VH differed significantly between the patients with RVO and the controls. The proteins identified may serve as potential biomarkers for pathogenesis induced by RVO.

Prospective, randomized, controlled clinical study evaluating the efficacy of Rheopheresis for dry age-related macular degeneration. Dry AMD treatment with Rheopheresis Trial-ART.

PURPOSE: To evaluate Rheopheresis for the treatment of patients with high-risk dry age-related macular degeneration and no therapeutic alternative. Rheopheresis is a method of therapeutic apheresis using the methodology of double filtration plasmapheresis to treat microcirculatory disorders. METHODS: The dry AMD treatment with Rheopheresis trial (ART) was a randomised, controlled clinical study. Patients with the diagnosis of AMD in both eyes, with the study eye presenting dry AMD and soft drusen (the fellow eye had advanced AMD) were randomly assigned in a 1:1 ratio to receive ten Rheopheresis treatments within 17 weeks or to remain untreated. The primary outcome was change in best-corrected ETDRS-visual acuity (mean logMar change) after 7.5 months compared to baseline visual acuity for both groups. RESULTS: Forty-three eyes of 43 patients (22 treatment and 21 control group) were analysed. The mean baseline BCVA in study eyes was 0.58 in the treatment group and 0.66 in the control group (n.s. p = 0.19). At the primary efficacy endpoint 7.5 months post baseline, there was a statistically significant mean difference of 0.95 ETDRS lines (p = 0.01) between the Rheopheresis and control groups. Nine percent of eyes in the group treated with Rheopheresis gained 2 or more ETDRS lines, as compared with 0% of eyes with no treatment. None of the treated patients had a loss in visual acuity in their study eyes, as compared with 24% of patients without treatment who lost 1 ETDRS line or more; 19% lost 2 ETDRS lines or more. Rheopheresis treatment was safe and well-tolerated. CONCLUSION: The results of ART provide further evidence that Rheopheresis is a safe and effective therapeutic option for high-risk patients with dry AMD and no therapeutic alternative. A series of Rheopheresis treatments can improve the natural course of AMD for selected patients.

'Mini-gauge' pars plana vitrectomy: 'inside-out view' with the GRIN solid rod endoscope.

PURPOSE: To stimulate the discussion about 'mini-gauge' pars plana vitrectomy. METHODS: Gradient index high-resolution endoscopy to analyze the 23- or 25-gauge access into the vitreous cavity. A total number of 66 pars plana interventions (almost 200 cannulas) were performed and recorded with the gradient index solid rod endoscope as well as through the microscope. RESULTS: Five main 'inside-out' observations were made through the endoscope. Some very slight rotating movement of the trocar was required to achieve a safe cannula implantation. Rotating the cannula too much could result in some unwanted side effects. The major amount of vitreous incarceration occurs during the implantation of cannulas. Incarcerated vitreous causes significant anterior-posterior vitreous traction. Intraocular cleaning of the port with the suction cutter releases the anterior-posterior traction without increasing the postoperative rate and degree of hypotony. Side effects like bleeding of the wound are likely to occur due to any sort of manipulation to the outside of the sclerotomy (i.e. cotton tips) other than the essential replacement of the conjunctiva. DISCUSSION: Surgeons who are considering the conversion to mini-gauge pars plana vitrectomy systems may be aided by endoscopic observations.

Pigment epithelium endoscopic laser surgery for treatment of choroidal neovascularization.

PURPOSE: To present a new concept and technique for subretinal surgery. METHODS: Twenty-four eyes of 24 patients with subfoveal choroidal neovascularization (CNV) were included in this study. Nine patients were operated on in Mexico City by one surgeon, 15 patients in Frankfurt by another surgeon. The retina at the posterior pole was detached and subretinal thermal photocoagulation of the CNVs was performed using a 20/19-gauge GRIN rod laser endoscope (Insight Instruments Inc., Sanford, Fla., USA). This procedure was termed PEELS (pigment epithelium endoscopic laser surgery). RESULTS: In 7 patients (Mexico), moderate improvement or stabilization of vision over 6 months or longer was achieved. In 10 out of 12 patients (Frankfurt), stabilization of vision over a follow-up period of 6-18 months was achieved, at least. Serious complications were not observed. Four of the Frankfurt series patients improved their vision. CONCLUSION: PEELS can stabilize or improve vision.