Tomohiro Otani

Patterns of Diabetic macular edema with Optical coherence tomography

PURPOSE We report cross-sectional images of diabetic macular edema and correlation between tomographic features and visual acuity with best correction by means of optical coherence tomography. METHOD In a prospective study, optical coherence tomography was performed in 59 eyes of 42 patients with diabetic macular edema and in 10 eyes of 10 normal control subjects. RESULTS Optical coherence tomography showed three patterns of structural changes in diabetic macular edema: sponge-like retinal swelling (52 [88%] of 59 eyes), cystoid macular edema (28 [47%] of 59 eyes), and serous retinal detachment (9 [15%] of 59 eyes). Some eyes had more than one pathologic change. Retinal swelling was more pronounced in the outer rather than the inner retinal layers. Cystoid macular edema was located mainly in the outer retinal layers. In eyes with long-standing cystoid macular edema, cystoid spaces had fused, resulting in a large cystoid cavity involving almost the entire retinal layer. Hard exudates were seen as highly reflective areas located in the outer retinal layers. The retinal thickness at the central fovea and the visual acuity with best correction showed an intermediate negative correlation in eyes without cystoid macular edema (correlation coefficient: -0.61, P < .01). CONCLUSIONS Diabetic macular edema involved three structural changes, including sponge-like retinal swelling (88%), cystoid macular edema (47%), and serous retinal detachment (15%). Visual acuity with best correction moderately correlated with retinal thickness regardless of the different tomographic features.

Tomographic assessment of vitreous surgery for diabetic macular edema

Abstract PURPOSE: To evaluate the retinal structure before and after vitrectomy for diabetic macular edema and to assess the correlation between thickness of neurosensory retina and best-corrected visual acuity. METHODS: Tomographic features of 13 eyes (nine patients) with diabetic macular edema were prospectively evaluated with optical coherence tomography before and after vitrectomy. The foveal thickness (the distance between the inner retinal surface and the retinal pigment epithelium) and the retinal thickness (thickness of neurosensory retina) were measured by optical coherence tomography preoperatively and postoperatively. The correlation of the best-corrected visual acuity with foveal and retinal thickness was determined. RESULTS: All 13 eyes had retinal swelling with low intraretinal reflectivity. In addition to retinal swelling, there were cystoid spaces in five (38%) of 13 eyes, a serous retinal detachment in three (23%), and both cystoid spaces and serous detachment in three (23%). Six months postoperatively, the mean foveal thickness significantly decreased from 630 ± 170 to 350 ± 120 μm (P CONCLUSIONS: Vitrectomy was generally effective in treatment of diabetic macular edema. Optical coherence tomography demonstrated the intraretinal changes of macular edema and the process of edema absorption. During the process of macular edema absorption, intraretinal fluid appeared to move into the subretinal space in some cases. Best-corrected visual acuity improvement was greater in eyes with less preoperative increase in thickness of neurosensory retina.

Effects of Age, Sex, and Axial Length on the Three-Dimensional Profile of Normal Macular Layer Structures

PURPOSE To identify sex-related differences and age-related changes in individual retinal layer thicknesses in a population of healthy eyes across the lifespan, using spectral domain optical coherence tomography (SD-OCT). METHODS In seven institutes in Japan, mean thicknesses of the retinal nerve fiber layer (RNFL), ganglion cell layer (GCL), inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), photoreceptor inner segment (IS), and photoreceptor outer segment (OS) were measured using SD-OCT with a new automated segmentation protocol in 256 healthy subjects. RESULTS Interoperator coefficients of variability for measurements of each layer ranged from 0.012 to 0.038. The RNFL, GCL, IPL, and INL were thinnest in the foveal area, whereas the OPL+ONL and OS were thickest in this area. Mean thicknesses of the INL and the OPL+ONL were significantly greater in men (P = 0.002 and 0.001, respectively). However, mean RNFL thickness was greater in women (P = 0.006). Thicknesses of the RNFL, GCL, IPL, INL, and IS correlated negatively with age. Thickness of the OPL+ONL was not correlated with age, and thickness of the OS correlated positively with age. Inner retinal (RNFL+GCL+IPL) thickness over the whole macula correlated negatively with age (P < 0.001), but outer retinal (OPL+ONL+IS+OS) thickness did not. Thicknesses of layers did not correlate with axial length. CONCLUSIONS Macular layer thicknesses measured on SD-OCT images in healthy eyes showed significant variations by sex and age. These findings should inform macular layer thickness analyses in SD-OCT studies of retinal diseases and glaucoma.

Correlation between visual acuity and foveal microstructural changes in diabetic macular edema.

Purpose: The purpose of this study was to investigate the correlation between best-corrected visual acuity and foveal microstructural changes of the external limiting membrane and the junction between the inner and outer segments of the photoreceptors in diabetic macular edema. Methods: The authors performed spectral-domain optical coherence tomography in all eyes. The authors defined central subfield thickness as the average retinal thickness of the 1-mm central scanned area. The length of disruption of the external limiting membrane and the inner and outer segments of the photoreceptors in the fovea (1.8 mm in diameter) were measured and graded according to their length as follows: 1) >1.4 mm; 2) >0.4 mm but <1.4 mm; or 3) <0.4 mm. Results: The best-corrected visual acuity was strongly associated with the external limiting membrane (r = 0.66) and inner and outer segments of the photoreceptor (r = 0.68) scores, whereas best-corrected visual acuity was weakly and negatively correlated with central subfield thickness (r = −0.23). Conclusion: Spectral-domain optical coherence tomography showed that the integrity of the external limiting membrane and inner and outer segments of the photoreceptors was more strongly correlated with best-corrected visual acuity when compared with central subfield thickness in diabetic macular edema.

A controlled study of vitrectomy for diabetic macular edema

PURPOSE To compare eyes that underwent surgery with untreated fellow eyes to assess the efficacy of vitrectomy for diabetic macular edema. METHODS In a nonrandomized clinical trial, seven adult patients with mean age of 53 years (range 42 to 64) and the same degree and duration of diabetic macular edema in both eyes were followed up for more than 5 months after unilateral vitrectomy. The treated eye was selected at random, but if visual disparity between the both eyes was more than 3 lines, we operated on the worse side. We compared the preoperative and postoperative foveal thicknesses (the distance between the inner retinal surface and retinal pigment epithelium) and the best-corrected visual acuity by a certified examiner with those of the untreated fellow eye. RESULTS In the seven eyes that underwent surgery, the foveal thickness decreased by an average of 622 to 269 microm (P =.027, Wilcoxon signed-rank test). In the fellow eyes, the average decrease in foveal thickness was from 617 to 546 microm (P =.176, Wilcoxon signed-rank test). The best-corrected postoperative visual acuity in the eyes that underwent surgery improved more than 2 lines in four eyes (57%) and remained the same in three eyes (43%). In the fellow eyes, it improved more than 2 lines in one eye (14%), remained the same in three eyes (43%), and decreased more than 2 lines in three eyes (43%). CONCLUSION In eyes with diabetic macular edema that underwent surgery, the foveal thickness significantly decreased after vitrectomy. Vitrectomy may be effective for treating diabetic macular edema.

Three-Dimensional Profile of Macular Retinal Thickness in Normal Japanese Eyes

PURPOSE To demonstrate the three-dimensional macular thickness distribution in normal subjects by spectral domain optical coherence tomography (SD-OCT) and evaluate its association with sex, age, and axial length. METHODS Mean regional retinal thickness measurements on the Early Treatment Diabetic Retinopathy Study (ETDRS) layout were obtained by three-dimensional raster scanning (6 x 6 mm) using SD-OCT in 248 normal eyes of 248 Japanese subjects. RESULTS Mean foveal thickness was 222 +/- 19 microm; it was significantly greater in men (226 +/- 19 microm) than in women (218 +/- 18 microm; P = 0.002) and did not correlate with age in either sex. Mean sectoral retinal thickness was also significantly greater in the men than in the women in all the quadrants of the inner ring (1-3 mm; P < 0.001 and P = 0.001-0.007) and in the temporal quadrant of the outer ring (3-6 mm; P < 0.001). The retinal thicknesses of each of the ETDRS sectors did not correlate significantly with axial length after adjustment for age in either sex. Retinal thickness in six of the eight sectors in the inner and outer rings showed a negative correlation with age after adjustment for axial length in the men (P < 0.001 and P = 0.001-0.018), whereas no correlation with age was observed in the women. CONCLUSIONS SD-OCT demonstrated the three-dimensional macular thickness distribution in normal eyes. Macular thickness varied significantly with sex and age. These variables should be considered while evaluating macular thickness.

Progressive enlargement of scattered photocoagulation scars in diabetic retinopathy.

Purpose: To clarify the evolution of laser scars and factors that possibly affect progression of laser-induced chorioretinal atrophy. Methods: The authors quantified 191 areas of laser scarring from panretinal photocoagulation in 19 eyes with diabetic retinopathy and calculated the expansion rate of the laser scars. They also analyzed factors affecting expansion, including location, laser wavelength, and follow-up period. The follow-up period ranged from 36 to 122 months (mean, 62 months). Results: Most (89.5%) laser scars gradually increased in size. The mean annual expansion rates were 12.7% in the posterior pole and 7.0% in the midperiphery. The annual expansion rate (16.5%) more than 4 years (late period) after treatment was higher than that (8.8%) within 4 years of treatment (early period). The expansion rate was minimal (1.2%) after argon laser treatment, whereas it was 11.7% after treatment with a 590-nm wavelength laser and 15.8% after treatment with a 610-nm wavelength laser. Conclusion: Laser photocoagulation causes relentless expansion of laser scars over a long period. Laser scars enlarged more in the posterior pole. Lasers of a longer wavelength contributed to larger areas of chorioretinal atrophy.

Tomographic findings of foveal hard exudates in diabetic macular edema

PURPOSE To report the intraretinal location of foveal hard exudates after vitrectomy to treat diabetic macular edema and to evaluate the visual outcome. METHODS In a prospective study, the tomographic features of 11 eyes (8 patients) with diabetic macular edema were evaluated with optical coherence tomography after vitrectomy. The intraretinal location of hard exudates at the fovea (anatomic foveola) and the relationship with visual acuity were investigated. RESULTS With optical coherence tomography, hard exudates were observed as highly reflective spots in the cross-sectional images. In six of 11 eyes (54.5%), the hard exudates were in the inner portion of the neurosensory retina; the final best-corrected visual acuity averaged 20/70 in the six eyes. In the remaining five eyes (45.5%), hard exudates were deposited not only in the neurosensory retina but also in the subretinal space. In optical coherence tomographic images, subretinal hard exudates were observed as highly reflective plaques, which were slightly elevated over the retinal pigment epithelium. The five eyes developed a serous retinal detachment at the fovea before or after vitrectomy. Subretinal hard exudates bridged the detached neurosensory retina and the retinal pigment epithelium in two eyes. The average final visual acuity level in the five eyes was 20/300. The visual outcome was significantly worse in five eyes with subretinal hard exudates than in six eyes with an intraretinal one (P <.05, Wilcoxon rank sum tests). CONCLUSIONS If serous retinal detachment develops before or after vitrectomy for diabetic macular edema, hard exudates tend to accumulate not only in the neurosensory retina but also in the subretinal space. The visual prognosis is worse in cases of subretinal exudation.

Improved visualization of Henle fiber layer by changing the measurement beam angle on optical coherence tomography.

Purpose: The outer plexiform layer (OPL) includes the photoreceptor synapse layer and Henle fiber layer (HFL) in the macular area. We attempted to improve optical coherence tomography imaging of the HFL by changing the angle of the measurement beam. Methods: Thirteen normal eyes underwent spectral domain optical coherence tomography. To focus the angle of the measurement beam perpendicular to the obliquely oriented HFL, the beam in the optical coherence tomography system was aimed at the periphery of the pupil. Results: The cross-sectional image of the macular area was inclined right or left if the beam entered from the periphery of the pupil. The reflectivity of the OPL increased because of strong backscattering of light in the half of the macula that was tilted down in cross-sectional images. On the opposite side, the reflectivity of HFL (the outer two-thirds of the OPL) decreased compared with that of the outer nuclear layer, but the photoreceptor synapse layer (the inner one-third of the OPL) remained highly reflective. The mean thicknesses of the OPL that could be visualized 1.0 mm and 1.5 mm from the central fovea were 73.7 ± 7.0 μm and 64.1 ± 8.2 μm, respectively. Conclusion: Positioning the measurement beam perpendicular to HFL enhanced visualization performance.

Serous macular detachment in branch retinal vein occlusion.

Purpose: To evaluate the relationship between the extent of branch retinal vein occlusion (BRVO) and the incidence of serous retinal detachment (SRD) in the macular area. Methods: One hundred nine eyes of 109 consecutive patients with BRVO comprised the study population. These eyes were characterized as having either macular BRVO or major BRVO. We compared the tomographic macular findings between the two groups. Results: Thirty-nine eyes had macular BRVO, and 70 eyes had major BRVO. The incidence of SRD was higher in the group with major BRVO (63%) than in the group with macular BRVO (21%) (P < 0.001). The incidence of cystoid macular edema was similar in both groups (macular BRVO, 97%; and major BRVO, 90%). Foveal thickness of major BRVO (610 ± 190 &mgr;m) was significantly greater than that of macular BRVO (500 ± 140 &mgr;m) (P < 0.01). There was no significant difference in thickness of the neurosensory retina between the group with macular BRVO (450 ± 120 &mgr;m) and the group with major BRVO (480 ± 140 &mgr;m). Conclusions: Serous macular detachment occurs more frequently in major BRVO than in macular BRVO. Vascular leakage from congested retinal veins outside the macular area appears to be a major source of subretinal fluid at the fovea.