Jae Suk Kim

Clinical Evaluation and Treatment Accuracy in Diabetic Macular Edema Using Navigated Laser Photocoagulator NAVILAS

PURPOSE To evaluate the clinical use and accuracy of a new retinal navigating laser technology that integrates a scanning slit fundus camera system with fluorescein angiography (FA), color, red-free, and infrared imaging capabilities with a computer steerable therapeutic 532-nm laser. DESIGN Interventional case series. PARTICIPANTS Eighty-six eyes of 61 patients with diabetic retinopathy and macular edema treated by NAVILAS. METHODS The imaging included digital color fundus photographs and FA. The planning included graphically marking future treatment sites (microaneurysms for single-spot focal treatment and areas of diffuse leakage for grid pattern photocoagulation) on the acquired images. The preplanned treatment was visible and overlaid on the live fundus image during the actual photocoagulation. The NAVILAS automatically advances the aiming beam location from one planned treatment site to the next after each photocoagulation spot until all sites are treated. Aiming beam stabilization compensated for patients eye movements. The pretreatment FA with the treatment plan was overlaid on top of the posttreatment color fundus images with the actual laser burns. This allowed treatment accuracy to be calculated. Independent observers evaluated the images to determine if the retinal opacification after treatment overlapped the targeted microaneurysm. MAIN OUTCOME MEASURES Safety and accuracy of laser photocoagulation. RESULTS The images were of very good quality compared with standard fundus cameras, allowing careful delineation of target areas on FA. Toggling from infrared, to monochromatic, to color view allowed evaluation and adjustment of burn intensity during treatment. There were no complications during or after photocoagulation treatment. An analysis of accuracy of 400 random focal targeted spots found that the NAVILAS achieved a microaneurysm hit rate of 92% when the placement of the treatment circle was centered by the operating surgeon on the microaneurysm. The accuracy for the control group analyzing 100 focal spots was significantly lower at 72% (P<0.01). CONCLUSIONS Laser photocoagulation using the NAVILAS system is safe and achieves a higher rate of accuracy in photocoagulation treatments of diabetic retinopathy lesions than standard manual-technique laser treatment. Precise manual preplanning and positioning of the treatment sites by the surgeon is possible, allowing accurate and predictable photocoagulation of these lesions. FINANCIAL DISCLOSURE(S) Proprietary or commercial disclosure may be found after the references.

External limiting membrane as a predictor of visual improvement in diabetic macular edema after pars plana vitrectomy

BackgroundTo evaluate the predictors of visual improvement using spectral-domain optical coherence tomography (SD-OCT) in eyes with resistant diabetic macular edema (DME) treated with pars plana vitrectomy.MethodsThirty-four eyes with resistant DME were evaluated in a retrospective manner. Several SD-OCT variables including photoreceptor inner segment/outer segment (IS/OS) junction, external limiting membrane (ELM) integrity, and central macular thickness (CMT) before and after the surgery, were evaluated by two experienced observers, masked to visual acuity. The visual improvement was used as the outcome measure for a stepwise regression, while the OCT factors were used as predictors.ResultsThe strongest predictor of vision improvement was pre-operative damage to the ELM (p = 0.0277) compared to IS/OS junction (p = 0.03). Pretreatment central macular thickness was a very weak predictor (p = 0.18) of visual improvement. For each percentage increase of ELM integrity there was a 0.13 letter gain in vision. ELM integrity explained 16% of the visual acuity improvement after treatment, which rose to 21% with the addition of CMT. The addition of IS/OS junction in the model did not add predictive information.ConclusionsEvaluation of ELM preoperatively predicts the vision improvement more accurately than the IS/OS junction and CMT in eyes with DME.

Hydrosilylated porous silicon particles function as an intravitreal drug delivery system for daunorubicin.

PURPOSE To evaluate in vivo ocular safety of an intravitreal hydrosilylated porous silicon (pSi) drug delivery system along with the payload of daunorubicin (DNR). METHODS pSi microparticles were prepared from the electrochemical etching of highly doped, p-type Si wafers and an organic linker was attached to the Si-H terminated inner surface of the particles by thermal hydrosilylation of undecylenic acid. DNR was bound to the carboxy terminus of the linker as a drug-loading strategy. DNR release from hydrosilylated pSi particles was confirmed in the excised rabbit vitreous using liquid chromatography-electrospray ionization-multistage mass spectrometry. Both empty and DNR-loaded hydrosilylated pSi particles were injected into the rabbit vitreous and the degradation and safety were studied for 6 months. RESULTS The mean pSi particle size was 30×46×15 μm with an average pore size of 15 nm. Drug loading was determined as 22 μg per 1 mg of pSi particles. An ex vivo drug release study showed that intact DNR was detected in the rabbit vitreous. An in vivo ocular toxicity study did not reveal clinical or pathological evidence of any toxicity during a 6-month observation. Hydrosilylated pSi particles, either empty or loaded with DNR, demonstrated a slow elimination kinetics from the rabbit vitreous without ocular toxicity. CONCLUSIONS Hydrosilylated pSi particles can host a large quantity of DNR by a covalent loading strategy and DNR can be slowly released into the vitreous without ocular toxicity, which would appear if an equivalent quantity of free drug was injected.

Predictors of visual outcome in eyes with choroidal neovascularization secondary to age related macular degeneration treated with intravitreal bevacizumab monotherapy.

AIM To evaluate the predictors of visual improvement in eyes with naive choroidal neovascularization secondary to age-related macular degeneration (CNV -AMD) treated with intravitreal bevacizumab (IVB) monotherapy. METHODS Fifty eyes with naive CNV- AMD with pretreatment best-corrected visual acuity (BCVA) better than 20/200 and treated with IVB monotherapy were evaluated. Several variables including age, sex, pre-treatment BCVA, CNV type and lesion size on fluorescein angiogram as well as SD-OCT parameters including pre-treatment central macular thickness (CMT), inner-segment/outer-segment (IS/OS) junction integrity, and external limiting membrane (ELM) integrity were analyzed to predict visual outcome. RESULTS On univariate regression, pretreatment ELM damage was associated with less visual improvement after treatment (P=0.0145). However, ELM damage predicted only 10% of the visual outcome. On multivariate regression, pretreatment BCVA, IS/OS junction, and ELM integrity on SD-OCT were the significant predictors for the treatment effect and together predicted 37% of visual improvement. CONCLUSION Pretreatment BCVA, ELM and IS/OS junction integrity on SD-OCT are of significant value in predicting the visual improvement in naive wet AMD patients treated with IVB monotherapy.

Focal navigated laser photocoagulation in retinovascular disease: clinical results in initial case series.

Purpose: To evaluate clinical results after the use of a novel integrated imaging and laser device to perform focal retinal navigated laser photocoagulation in perifoveal abnormalities and retinovascular disease. Methods: Interventional case series of 25 consecutive eyes with perifoveal and retinovascular diseases treated with a navigated laser photocoagulator Navilas (OD-OS, Berlin, Germany). We treated eyes with perifoveal telangiectasia (n = 3), central serous chorioretinopathy (n = 2), and diabetic macular edema with focal leakage (n = 20). Results: The treatments were performed without a contact lens and without topical anesthesia. There was no inadvertent photocoagulation of the fovea, and all laser applications accurately hit the preplanned points. Mean and median (± standard deviation) foveal thickness at baseline was 535 ± 171 &mgr;m and 402 ± 152 &mgr;m, respectively. Mean and median (± standard deviation) foveal thickness at 6 months was 318 ± 112 &mgr;m and 221 ± 127 &mgr;m, respectively. This represents a statistically significant decrease in foveal thickness (P = 0.003). Mean and median visual acuity at baseline was 20/80 and 20/50, respectively. Mean and median visual acuity at 6 months was 20/50 and 20/40, respectively, which represents a significant improvement (P = 0.011). Conclusion: Precise retinal targeting with a navigated laser photocoagulator resulted in highly accurate perifoveal laser application and no foveal damage. At 6 months after the treatment, significant decreases in central foveal thickness and significant improvements in visual acuity were identified.

Retinal adherence and fibrillary surface changes correlate with surgical difficulty of epiretinal membrane removal.

PURPOSE To correlate surgical difficulty of epiretinal membrane (ERM) removal with characteristics of ERM adherence seen by spectral-domain optical coherence tomography (SD-OCT). DESIGN Prospective observational case series. METHODS Surgical difficulty was correlated with extent of ERM adherence by SD-OCT using masked observers in consecutive eyes undergoing ERM removal (N=31). Surgical videos were analyzed and difficulty of ERM removal (grade 1-3) was determined in 4 quadrants as well as the fovea by consensus of observers masked to SD-OCT findings. Extent of ERM adhesion was categorized (focal, broad, or complete) by masked observers using SD-OCT. The presence of fibrillary changes between the ERM and retinal nerve fiber layer (RNFL) was also evaluated. Surgical difficulty of ERM removal for each quadrant and fovea was compared to extent of ERM adherence and presence of fibrillary changes. RESULTS Assessment of ERM adherence using SD-OCT between masked observers was highly concordant (kappa=0.9178). Surgical difficulty of ERM removal was strongly associated with more extensive ERM adherence to the retina observed by SD-OCT. Complete ERM adherence correlated with an 8.6-fold increased surgical difficulty of ERM removal compared to focal adherence (P<.0001). The presence of fibrillary changes between the ERM and RNFL also correlated with a 25.5-fold increased difficulty of surgical removal compared to the absence of fibrillary changes (P<.0001). CONCLUSION Extent of ERM-retinal adhesion and presence of fibrillary changes determined by SD-OCT provide reliable preoperative assessment of surgical difficulty. Furthermore, SD-OCT analysis may help localize surgically advantageous coordinates to initiate ERM removal.

Restoration of retinal layers after epiretinal membrane peeling

Purpose: To evaluate the morphologic restoration of retinal anatomy after surgery for epiretinal membrane (ERM) peeling using spectral domain optical coherence tomography. Correlation of retinal structure with visual outcome. Design: Retrospective consecutive case series. Methods: Thirty-four consecutive eyes with ERM underwent surgery with 1 year follow-up examination. Spectral domain optical coherence tomography scans were analyzed preoperatively and 1, 3, 6, 9, and 12 months postoperative. Best-corrected visual acuity (BCVA) using Early Treatment Diabetic Retinopathy Study charts was measured at each visit. Results: All eyes showed a significant improvement of BCVA after ERM peeling (P = 0.002). The time point of BCVA and retinal restoration seen on spectral domain optical coherence tomography occurred simultaneously and varied between individuals (occurrence of BCVA: mean, 4.82 months; retinal restoration: mean, 4.24 months). At 3 months, the retinal anatomical restoration rate was 70% and 88% at 6 months. Conclusion: Restoration of the retinal anatomical structure predominantly occurs within the first 3 months post-ERM peeling. An improvement of BCVA and anatomical retinal restoration after ERM removal varies in individuals. If retinal layers fully restore in their anatomical structure, BCVA improves at the same time point.

Fundus autofluorescence not predictive of treatment response to intravitreal bevacizumab in exudative age-related macular degeneration.

Purpose: Foveal autofluorescence (AF) has been suggested to be a potential predictor of treatment outcome in choroidal neovascularization (CNV) secondary to age-related macular degeneration and could be a useful marker to help prognosticate for patients and for clinical trials. This retrospective study aims to determine if pretreatment foveal AF can predict treatment response to intravitreal bevacizumab monotherapy in CNV secondary to age-related macular degeneration. Methods: Ninety-five eyes (85 patients) with naive CNV secondary to age-related macular degeneration, treated with intravitreal bevacizumab monotherapy were included in this study. Lesion size, CNV type on fluorescein angiography, pretreatment best-corrected visual acuity, and foveal AF pattern (intact/nonintact) were used as predictors. Multivariate linear regression and logistic regression were performed using best-corrected visual acuity change and anatomical response at 6 months as the dependent variables separately. Results: Pretreatment foveal AF (intact or nonintact) did not predict visual outcome (P = 0.17) nor did lesion size (P = 0.2) or CNV type (P = 0.61). Foveal AF did correlate with the visual acuity but it did not predict any treatment response. Pretreatment best-corrected visual acuity was the only predictive factor for the visual outcome (P = 0.043). Conclusion: Pretreatment AF is not a predictor for the treatment response to intravitreal bevacizumab monotherapy in eyes with CNV secondary to age-related macular degeneration.