Yeon Sung Moon

Optical coherence tomographic patterns in diabetic macular oedema: prediction of visual outcome after focal laser photocoagulation

Aim: To identify optical coherence tomography (OCT) patterns predictive of visual outcome in diabetic macular oedema (DMO) patients who undergo focal laser photocoagulation. Methods: This study involved 70 eyes (45 patients) with clinically significant macular oedema that underwent focal laser photocoagulation using the Early Treatment Diabetic Retinopathy Study protocol. Preoperative macular OCT images were retrospectively examined. OCT features were classified into four patterns: diffuse retinal thickening (DRT); cystoid macular oedema (CMO), serous retinal detachment and vitreomacular interface abnormalities (VMIA). Changes in retinal thickness, retinal volume and visual acuity (VA) after focal laser photocoagulation were evaluated and compared with respect to their OCT features. Results: After focal laser photocoagulation, changes in retinal thickness and retinal volume were significantly different for different OCT types (p = 0.002 and p<0.001). The change in VA from baseline was not significantly different between groups (p = 0.613). The DRT pattern was associated with a greater reduction in retinal thickening and better VA improvement than the CMO or VMIA patterns. Proportions of patients with persistent DMO (central macular thickness >250 μm after laser treatment) were greater for the CMO and VMIA patterns than DRT pattern. Conclusion: DRT patients achieved a greater reduction in retinal thickening and greater VA increases than CMO and VMIA patients. We suggest that classifying DMO structural patterns using OCT might allow visual outcome to be predicted after laser photocoagulation.

Relations between Age, Weight, Refractive Error and Eye Shape by Computerized Tomography in Children

Purpose To investigate relationships between age, weight, refractive error, and morphologic changes in childrens eyes by computerized tomography (CT). Methods Of the 772 eyes of 386 patients under the age of 20 years, who visited our Department of Ophthalmology between January 2005 to August 2006 and underwent CT of the orbit, 406 eyes of 354 patients with clear CT images and normal eyeball contour were enrolled in the present retrospective study. The axial lengths, widths, horizontal and vertical lengths, refractive errors, and body weight of eyes were measured, and relationship between these parameters were investigated. Results Axial length was found to correlate significantly with eye width (r=0.914), and in emmetropic eyes and myopic eyes, axial lengths and widths were found to increase as age and body weight increased. Axial lengths increased rapidly until age 10, and then increased slowly. In emmetropic eyes, widths / axial lengths increased with age, but in myopic eyes these decreased as age or severity of myopia increased. Moreover, as age increased, the myopic population and severity also increased. Conclusions The axial length was longer in case of myopia compared to emmetropia in all age groups and there was almost no difference in the increase rate of axial length by the age of myopia and emmetropia. However, the width was wider in case of myopia compared to emmetropia in all age groups and the increase rate of width in myopia by age was smaller than that of emmetropia. Myopia showed decreasing rate of width/axial length with increase of age, from 1.004 in 5 years to 0.971 in 20 years. However, emmetropia showed increasing rate of width/axial length with increase of age, from 0.990 in 5 years to 1.006 in 20 years.

Intravitreal Bevacizumab Alone versus Combined with Macular Photocoagulation in Diabetic Macular Edema

Purpose To compare the efficacy between intravitreal bevacizumab and combination treatment (bevacizumab and macular photocoagulation) for the treatment of diabetic macular edema (DME). In addtion, changes of DME type were researched using optical coherence tomography. Methods The present study included 90 eyes with bevacizumab injection and 38 eyes with combination treatment. Using chart records, patients were reviewed until 6 months after treatment. The present study compared changes of visual acuity (VA) and macular thickness at each follow up. DME was classified into 4 types and the morphologic pattern was compared. Results In patients with the bevacizumab injection only, VA improved from 0.29 ± 0.18 to 0.48 ± 0.26 at 1 month and returned to 0.32 ± 0.20 at 6 months after treatment. In the combination treatment, VA improved from 0.32 ± 0.22 to 0.52 ± 0.26 at 1 month and returned to 0.36 ± 0.18 at 6 months after treatment. There was no significant improvement of VA at the final follow-up with either treatment. There was significant decrease of macular thickness except in the mixed DME type. Conclusions The combination treatment did not yield better VA or macular thickness reduction at 6 months than bevacizumab injection alone. By classifying and observing the change of DME type, determining the treatment objectively and predicting the effectiveness of treatment can be helpful.

Effects of Vitreomacular Traction on Ranibizumab Treatment Response in Eyes with Neovascular Age-related Macular Degeneration

Purpose To investigate the effects of vitreomacular traction (VMT) on ranibizumab treatment response for neovascular age-related macular degeneration (AMD). Methods A retrospective review of 85 eyes of 85 patients newly diagnosed with neovascular AMD was conducted. Patients were eligible if they had received more than three consecutive monthly ranibizumab (0.50 mg) treatments and ophthalmic evaluations. Patients were classified into a VMT (+) group or VMT (-) group according to optical coherence tomography imaging. Best corrected visual acuity and central retinal thickness (CRT) measurements were obtained at three and six months after initial injection. Results One month after the third injection, mean visual acuity (VA) increases of 6.36 and 9.87 letters were observed in the VMT (+) and VMT (-) groups, respectively. The corresponding mean CRT values decreased by 70.29 µm and 121.68 µm, respectively. A total 41 eyes were identified as eligible for a subsequent fourth injection; 71.1% of patients (27 eyes) in the VMT (+) group but only 29.8% of patients in the VMT (-) group needed a subsequent fourth injection. Follow-up was extended to six months for 42 of the 85 enrolled patients (49.4%). The trends in VA and optical coherence tomography were found to be maintained at six-month follow-up. Conclusions VA and CRT appeared to be more improved after ranibizumab treatment in the VMT (-) group compared to the VMT (+) group. VMT might antagonize the effect of ranibizumab treatment in a subpopulation of AMD patients.

Early changes in retinal structure and BMP2 expression in the retina and crystalline lens of streptozotocin-induced diabetic pigs

Purpose This study aims to evaluate early changes in retinal structure and BMP2 expression in the retina and crystalline lens by comparing streptozotocin-induced diabetic pigs and normal control group pigs. Methods Five eye samples from five diabetic Micro-pigs (Medikinetics, Pyeongtaek, Korea) and five eye samples from five control pigs bred in a specific pathogen-free area were used. Diabetes was developed through intravenous injection of nicotinamide and streptozotocin, and the average fasting glucose level was maintained at 250 mg/dL or higher for 16 weeks. To evaluate BMP2 expression in the retina and crystalline lens, Western blotting was performed. Results In Hematoxylin and Eosin staining, most diabetic pigs showed structural abnormalities in the inner plexiform layer. The number of nuclei in the ganglion cell layer within the range of 104 µm2 was 3.78±0.60 for diabetic pigs and 5.57±1.07 for control group pigs, showing a statistically significant difference. In immunohistochemical staining, diabetic retinas showed an overall increase in BMP2 expression. In Western blotting, the average BMP2/actin level of diabetic retinas was 1.19±0.05, showing a significant increase compared to the 1.06±0.03 of the control group retinas (P=0.016). The BMP2/actin level of diabetic crystalline lenses was similar to the control group crystalline lenses (P=0.730). Conclusions Compared to control group pigs, the number of nuclei in the inner nuclear layer of retinas from streptozotocin-induced diabetic pigs decreased, while an increase in BMP2 expression was observed in the retina of diabetic pigs.

Treatment of Diabetic Macular Edema – Latest Therapeutic Developments

Macular edema is a frequent manifestation of diabetic retinopathy and an important cause of impaired vision in individuals with diabetes (Klein et al., 1984; Moss et al., 1998). The Wisconsin Epidemiologic Study of Diabetic Retinopathy (WESDR), a population-based study in southern Wisconsin, estimated that after 20 years of known diabetes, the prevalence of diabetic macular edema (DME) was approximately 28% in both type 1 and type 2 diabetes (Klein, et al., 1984)