Retinal thickness study with optical coherence tomography in patients with diabetes

PURPOSE: To quantitatively assess retinal thickness by optical coherence tomography (OCT) in normal subjects and patients with diabetes. This study was intended to determine which retinal thickness value measured with OCT best discriminates between diabetic eyes, with and without macular edema. METHODS: OCT retinal thickness was measured by a manual technique in a total of 26 healthy volunteers (44 control eyes) and 85 patients with diabetes (148 eyes) with the clinical diagnosis of no diabetic retinopathy (45 eyes), nonproliferative diabetic retinopathy without clinically significant macular edema (CSME; 54 eyes), proliferative diabetic retinopathy without CSME (21 eyes), and 28 eyes with diabetic retinopathy with CSME. Independent predictors of the presence of CSME were quantified by using univariate and multivariate logistic regression analyses. Receiver operating characteristic (ROC) curves were generated to evaluate and compare the predictor variables. The correlation of retinal thickness measurements and visual acuity was calculated. RESULTS: There were statistically significant differences in foveal thickness between control eyes and all the other eye groups (P = 0.001). Diabetic eyes with CSME had a statistically significant greater thickness in each of the areas compared with the other groups. In a multivariate logistic regression model, foveal thickness was a strong and independent predictor of CSME (odds ratio [OR], 1.037; 95% confidence interval [CI] 1.02-1.05). The area under the ROC curve of this predictor variable was 0.94 (P = 0.001). For a cutoff point of 180 microm, the sensitivity was 93%, and specificity was 75%. Foveal thickness correlated with visual acuity in a log minimum angle of resolution (logMAR) scale (Spearman's rho = 0.9, P = 0.001). CONCLUSIONS: These results suggest that foveal thickening over 180 microm measured by OCT may be useful for the early detection of macular thickening and may be an indicator for a closer follow-up of the patient with diabetes.     

Quantitative assessment of retinal thickness in diabetic patients with and without clinically significant macular edema using optical coherence tomography

PURPOSE: To assess patients with diabetic macular edema quantitatively using optical coherence tomography (OCT). METHODS: OCT was performed in 14 eyes with diabetic retinopathy and ophthalmoscopic evidence of clinically significant macular edema (CSME) and in 19 diabetic eyes without CSME. Retinal thickness was computed from the tomograms at fovea and other 36 locations throughout the macula. RESULTS: The mean +/- standard deviation foveal thickness was 255.6 +/- 138.9 microm in eyes with CSME, and 174.6 +/- 38.2 microm in eyes without CSME (p = 0.051). Within 2000 microm of the center of the macula, eyes with CSME had significantly thicker retina in the inferior quadrant than those without CSME (p < 0.01). The foveal thickness was correlated with logMAR visual acuity (gamma = 0.68, p < 0.01). OCT identified sponge-like retinal swelling and/or cystoid macular edema in 11 (58%) eyes without CSME, and in 12 (86%) eyes with CSME. CONCLUSIONS: Criteria of CSME seem to be insufficient in really identifying macular edema. OCT may be more sensitive than a clinical examination in assessing diabetic macular edema and is a quantitative tool for documenting changes in macular thickening.     

Can optical coherence tomography predict the outcome of laser photocoagulation for diabetic macular edema?

BACKGROUND AND OBJECTIVE: To assess the outcome of laser photocoagulation in patients with diabetic macular edema. PATIENTS AND METHODS: Forty-seven patients (51 eyes) with clinically significant macular edema (CSME) undergoing grid laser photocoagulation were included. Clinical examination and optical coherence tomography (OCT) were performed at baseline and 3 to 4 months after treatment. The central foveal thickness, mean inner macular thickness (average retinal thickness in fovea and inner macular circle), and mean macular thickness were calculated. Based on the greatest OCT thickness at baseline, patients were grouped according to mild (< 300 microm; Group 1), moderate (300 to 399 microm; Group 2), and severe (> or = 400 microm; Group 3) macular edema. RESULTS: Group 2 showed significant reductions in central foveal thickness (23 microm, P = .02), mean inner macular thickness (18 microm, P = .02), and mean macular thickness (9 microm, P = .04) with slight improvement in visual acuity. Groups 1 and 3 did not show any significant change in macular thickness values and there was a statistically insignificant worsening of visual acuity in these groups. CONCLUSIONS: Patients with moderate macular thickening of 300 to 400 microm benefit most from laser treatment. OCT may help in choosing the appropriate treatment for CSME based on the degree of macular thickening. Long-term studies are warranted to confirm these findings.     

Comparison of optical coherence tomography models OCT1 and Stratus OCT for macular retinal thickness measurement

AIMS: To compare the values measured for retinal macular thickness with the first and last generations of the optical coherence tomograph (OCT1 and Stratus OCT, Zeiss, Humphrey Division). METHODS: This was a cohort study. 59 eyes were examined: 17 had a normal macula and 42 had a diabetic macular oedema. In each eye, mean retinal thickness (RT) was measured automatically in the nine macular Early Treatment Diabetic Retinopathy Study areas and at the foveal centre, using OCT1 and Stratus OCT. The paired mean RT values for each area and the type and proportion of artefacts were compared. RESULTS: Of the 590 automatic measurements, 505 had no artefact, either with OCT1 or Stratus OCT. The mean difference between the OCT1 and Stratus OCT measurements was 25 (SD 26.2) microm (p<0.0001). With Stratus OCT, RT values were significantly higher, by 8.1% (7.8%), than with OCT1. Artefacts were only observed in cases of diabetic macular oedema and were significantly more frequent with OCT1 than Stratus OCT (10.5% versus 4.4, p<0.0001). CONCLUSION: The macular retinal thickness values measured with Stratus OCT were significantly higher than those measured with OCT1. Stratus OCT has the advantage of producing fewer artefacts than OCT1 in pathological cases.     

Retinal thickness on Stratus optical coherence tomography in people with diabetes and minimal or no diabetic retinopathy

PURPOSE: To evaluate optical coherence tomography (OCT) thickness of the macula in people with diabetes but minimal or no retinopathy and to compare these findings with published normative data in the literature from subjects reported to have no retinal disease. DESIGN: Cross-sectional study. METHODS: In a multicenter community- and university-based practices setting, 97 subjects with diabetes with no or minimal diabetic retinopathy and no central retinal thickening on clinical examination and a center point thickness of 225 microm or less on OCT (Stratus OCT; Carl Zeiss Meditec, Dublin, California, USA) were recruited. Electronic Early Treatment of Diabetic Retinopathy Study best-corrected visual acuity, seven-field stereoscopic color fundus photographs, and Stratus OCT fast macular scan were noted. Main outcome measures were central subfield (CSF) thickness measured on Stratus OCT. RESULTS: On average, CSF thickness was 201 +/- 22 microm. CSF thickness was significantly greater in retinas from men than retinas from women (mean +/- standard deviation, 209 +/- 18 microm vs 194 +/- 23 microm; P < .001). After adjusting for gender, no additional factors were found to be associated significantly with CSF thickness (P > .10). CONCLUSIONS: CSF thicknesses on Stratus OCT in people with diabetes and minimal or no retinopathy are similar to thicknesses reported from a normative database of people without diabetes. CSF thickness is greater in men than in women, consistent with many, but not all, previous reports. Studies involving comparisons of retinal thickness with expected norms should consider different mean values for women and men.     

Intravitreal triamcinolone for refractory diabetic macular edema

PURPOSE: To determine if intravitreal injection of triamcinolone acetonide is safe and effective in treating diabetic macular edema unresponsive to prior laser photocoagulation. DESIGN: Prospective, noncomparative, interventional case series. PARTICIPANTS: Sixteen eyes with clinically significant diabetic macular edema (CSME) that failed to respond to at least two previous sessions of laser photocoagulation. METHODS: Eyes were diagnosed with CSME and treated with at least two sessions of laser photocoagulation according to Early Treatment Diabetic Retinopathy Study guidelines. At least 6 months after initial laser therapy, the response was measured by clinical examination and optical coherence tomography (OCT). Eyes with a residual central macular thickness of more than 300 microm (normal, 200 microm) and visual loss from baseline were offered intravitreal injection of 4 mg triamcinolone acetonide. The visual and anatomic responses were observed as well as complications related to the injection procedure and corticosteroid medication. MAIN OUTCOME MEASURES: Visual acuity and quantitative change in OCT macular thickening were assessed. Potential complications were monitored, including intraocular pressure response, cataract progression, retinal detachment, vitreous hemorrhage, and endophthalmitis. RESULTS: All patients completed 3 months of follow-up, and 8 of 16 patients (50%) completed 6 or more months of follow-up. Mean improvement in visual acuity measured 2.4, 2.4, and 1.3 Snellen lines at the 1-, 3-, and 6-month follow-up intervals, respectively. The central macular thickness as measured by OCT decreased by 55%, 57.5%, and 38%, respectively, over these same intervals from an initial pretreatment mean of 540.3 microm (+/-96.3 microm). Intraocular pressure exceeded 21 mmHg in 5, 3, and 1 eye(s), respectively, during these intervals. One eye exhibited cataract progression at 6 months. No other complications were noted over a mean follow-up of 6.2 months. Reinjection was performed in 3 of 8 eyes after 6 months because of recurrence of macular edema. CONCLUSIONS: Intravitreal triamcinolone is a promising therapeutic method for diabetic macular edema that fails to respond to conventional laser photocoagulation. Complications do not appear to be prohibitive. Further study is warranted to assess the long-term efficacy and safety, and the need for retreatment.     

Retinal thickness in diabetic retinopathy: comparison of optical coherence tomography, the retinal thickness analyzer, and fundus photography

BACKGROUND: Optical coherence tomography (OCT) and the retinal thickness analyzer (RTA) have proved their ability to measure retinal thickness in healthy subjects and diabetics reliably. In the present study, both techniques were compared for the same study population of diabetic patients, and the findings were related to macular edema shown by stereo fundus photography (SFP). METHODS: Maculas of 124 eyes from 69 patients with diabetes mellitus were examined with OCT and the RTA. Measurements of retinal thickness were compared with signs of macular edema shown by SFP. For each eye, nine different sectors were analyzed (a foveal sector, four parafoveal sectors, and four extrafoveal sectors). Thirteen eyes with a normal macula served as controls. Sensitivity and specificity of detecting clinically significant macular edema (CSME) were calculated. RESULTS: Of 111 eyes, 64 showed signs of CSME by SFP. Mean retinal thickness +/- SD of the foveal sector was 249 +/- 104 microm by RTA and 295 +/- 124 microm by OCT measurements. There was a moderate overall correlation between OCT and the RTA (r = 0.66). The correlation was best in the foveal sector (r = 0.82). Overall correlation with SFP was better for OCT (r = 0.77) than for the RTA (r = 0.62). Sensitivity of detecting CSME was consistently higher with OCT, while the RTA showed higher specificity. CONCLUSION: Both measuring techniques yielded similar results when examining eyes of patients with diabetes, although absolute values differed. OCT seems to be more suitable in the clinical screening for macular edema due to its high sensitivity (>90%) with appropriate analysis parameters. The RTA is more prone to erroneous or missing thickness readings particularly under difficult measuring conditions.     

Temporal variation in diabetic macular edema measured by optical coherence tomography

PURPOSE: To determine, by optical coherence tomography (OCT), whether there is a quantitative decrease in macular edema in diabetic subjects over the course of a day. STUDY DESIGN: Observational case series. PARTICIPANTS: Ten subjects with diabetic macular edema in 1 or both eyes. METHODS: Subjects were admitted to the hospital the evening before the study so that they would remain in the recumbent position until immediately before study measurements began. They then underwent 4 OCT measurements of macular thickness in both eyes, at 8:00 am, 11:00 am, 2:00 pm, and 5:00 pm. At each of these times, they also had refractions and visual acuity measurements using the Early Treatment Diabetic Retinopathy Study protocol. Macular thickness measurements determined by the Zeiss-Humphrey (Dublin, CA) optical coherence tomograph for each eye of each subject were plotted as a function of time. MAIN OUTCOME MEASURES: Temporal changes in retinal thickness in each of the 9 macular sectors defined by the OCT protocol and in the entire macula of each eye, averaged from all 9 sectors; temporal changes in refractive error and visual acuity. RESULTS: Four of the 10 subjects showed consistent decreases in macular thickness over the course of the day in 1 or more of the retinal sectors in 1 or both eyes. When macular thickness values were averaged over all 9 sectors for all subjects, both eyes showed consistent declines in mean thickness throughout the day. By t test, the 8 am value in each eye was significantly higher (P<0.0005) than any of the 3 later values, which did not differ significantly from each other. However, comparison of all 4 values by analysis of variance showed no significant differences. With the exception of 1 subject, there were no consistent changes in refractive error or in best-corrected visual acuity over the course of the study. CONCLUSIONS: This study, using quantitative OCT determinations, seems to confirm the much earlier report by Sternberg et al, which used more subjective methods, that macular edema might vary over the day. That the 8 am value, obtained just after waking, was higher than the 3 later values (highly significant by 1 test) suggests that the decrease in macular thickness is most likely due to the shift from recumbent to upright body position, although our study protocol did not exclude other possible mechanisms. Although changes in macular thickness over the course of the day did not occur in all subjects, therapeutic studies for macular edema that use OCT as an outcome measure should control for time of day when these measurements are carried out.     

Effect of grid laser photocoagulation in diffuse diabetic macular edema in correlation to glycosylated haemoglobin (HbA1c)

Background Glycosylated haemoglobin (HbA1c) correlates with the amount of hyperglycemia in diabetic patients. High HbA1c levels often predict clinically significant macular edema (CSME), which then needs to be treated with grid laser photocoagulation. The question asked in this study was whether there is a correlation between the effect grid laser photocoagulation in diffuse diabetic macular edema and HbA1c, using an optical coherence tomography (OCT) for the evaluation of the retinal thickness. Methods A prospective, non-comparative case series was performed to find a correlation between the effect of grid laser photocoagulation in diffuse diabetic macular edema and HbA1c. Thirty eyes with CSME of diabetic patients were included in the study. Complete ophthalmic examinations and OCT were performed at baseline, 1 month, 3, and 6 months after grid laser photocoagulation therapy. HbA1c was measured at the end of study. Results Significance level was set at P<0.05. A significant difference in the foveal (P=0.02) and superior (P=0.021) retinal thickness 6 months after laser therapy, no correlation between HbA1c and retinal thickness after photocoagulation, and an insignificant decrease in visual acuity (P=0.9) were found. The correlation between foveal retinal thickness and visual acuity was P=0.24 6 months after treatment. Conclusion There was no significant correlation between HbA1c and the effect of grid laser photocoagulation therapy in diffuse diabetic macular edema. The retinal thickness decreased significantly in the foveal and superior area 6 months after therapy. No correlation between the foveal retinal thickness and the visual acuity was found. The visual acuity did not increase after treatment. There are many factors influencing the retinal thickness, such as the blood pressure and the attached posterior hyaloid.     

Retinal thickness in diabetic retinopathy: a study using optical coherence tomography (OCT)

BACKGROUND AND OBJECTIVE: The authors conducted a controlled study to quantify macular retinal thickness in diabetic retinopathy using optical coherence tomography (OCT) as an objective and noninvasive tool. The relationship between retinal thickness and standard methods of evaluating macular edema was investigated. PATIENTS AND METHODS: A total of 136 patients in different stages of diabetic retinopathy were examined with OCT. In addition, fluorescein angiograms as well as standard eye examinations were conducted. The control group consisted of 30 individuals with a normal macula. RESULTS: In the controls, retinal thickness was 153 +/- 15 microm in the fovea, 249 +/- 19 microm in the temporal parafoveal region, and 268 +/- 20 microm in the nasal parafoveal region. In diabetic patients, retinal thickness was increased to 307 +/- 136 microm in the fovea, 337 +/- 88 microm in the temporal retina, and 353 +/- 95 microm in the nasal retina, respectively. The differences between diabetics and controls were highly significant (P < 0.001). Retinal thickening correlated with fluorescein leakage in the angiograms to some extent. There was an intermediate correlation between retinal thickness and visual acuity, particularly in patients without macular ischemia. Sensitivity of detecting clinically significant macular edema by measuring foveal retinal thickness was 89% and specificity was 96%. CONCLUSION: Optical coherence tomography allows us to quantify retinal thickness in diabetic retinopathy with excellent reproducibility. OCT is able to detect sight-threatening macular edema with great reliability.     

Diabetic macular oedema and visual loss: relationship to location,severity and duration

Purpose: To assess the relationship between visual acuity (VA) and diabetic macular oedema (DMO) in relation to the location of retinal thickening and the severity and duration of central macular thickening. Methods: Data from 584 eyes in 340 placebo‐treated patients in the 3‐years‐long Protein Kinase C Diabetic Retinopathy Study (PKC‐DRS2) trial were used to investigate the relationship between VA and DMO. Eligible eyes had moderately severe to very severe non‐proliferative diabetic retinopathy and VA of at least 45 letters on Early Treatment Diabetic Retinopathy Study (ETDRS) charts (Snellen equivalent = 20/125). Diabetic retinopathy and DMO status were assessed using stereo photographs. Results: Nearly one third of study eyes had foveal centre‐involving DMO at the start of the trial. Sustained moderate visual loss was found in 36 eyes, most commonly associated with DMO at the centre of the fovea in 73% of eyes. There was a strong relationship (p < 0.001) between foveal centre involvement with DMO and mean VA. Mean VA decreased with increasing retinal thickness at the centre (p < 0.001) and increasing duration of centre‐involving DMO (p < 0.001). Conclusion: This study documents the relationship between duration of DMO and progressive vision loss, and the key role of central foveal involvement in patients with diabetic retinopathy. These data will help to develop future strategies to prevent vision loss.     

Diabetic macular edema: correlation between microperimetry and optical coherence tomography findings

PURPOSE: To compare the changes in macular sensitivity (microperimetry) and macular thickness with different degrees of diabetic macular edema. METHODS: Sixty-one eyes of 32 consecutive diabetic patients were included in this cross-sectional study. All included eyes underwent functional and morphologic examination of the macular area. Best corrected visual acuity (ETDRS charts), macular sensitivity, and macular thickness were quantified. Lesion-related macular sensitivity and retinal fixation were investigated with an advanced, automatic microperimeter. Optical coherence tomography (OCT) was used to quantify macular thickness. RESULTS: The 61 included eyes were graded, by two retinal specialists, for diabetic macular edema as follows: 16 were graded as no macular edema (NE), 30 as non-clinically significant macular edema (NCSME), and 15 as clinically significant macular edema (CSME). Macular thickness significantly increased from the NE to the CSME group (P<0.0001), whereas macular sensitivity significantly decreased from the NE to the CSME group (P<0.0021). A significant correlation coefficient was noted between retinal sensitivity and normalized macular thickness (r=-0.37, P<0.0001). Linear regression analysis showed a decrease of 0.83 dB (P<0.0001) for every 10% of deviation of retinal thickness from normal values. Visual acuity and central macular sensitivity correlated significantly in the NCSME group (r=-0.6, P=0.0008), but not in the NE (r=-0.144, P=0.6) or in the CSME (r=-0.46, P=0.11) groups. CONCLUSIONS: Macular edema may be better documented by adding macular sensitivity mapping by microperimetry to macular thickness measurement by OCT and visual acuity determination because macular sensitivity seems to be a relevant explanatory variable of visual function, independent of macular thickness data. Moreover, microperimetry may be of value in predicting the outcome of diabetic macular edema, because it incorporates a functional measure that may supplement the predictive value of OCT and visual acuity.     

The association between visual acuity and central retinal thickness in retinitis pigmentosa

PURPOSE: To determine whether visual acuity is related to central retinal thickness in patients with retinitis pigmentosa. METHODS: Visual acuities were measured with Early Treatment Diabetic Retinopathy Study (ETDRS) charts and optical coherence tomography (OCT3) was used to calculate retinal thicknesses and grade third high-reflectance bands in 162 patients with the typical forms of retinitis pigmentosa who had Snellen visual acuities of 20/20 to 20/200, minimal to no cataracts, and no visible macular cysts. Sixty-five patients were retested within 2 months to estimate the intervisit variability of retinal thickness measurements. RESULTS: ETDRS acuity was best related to retinal thickness measured at fixation and as the average value over the central 1 mm by a second-order polynomial (r(2) = 0.38 and P < 0.001 in both cases). Acuity was maximal for intermediate retinal thickness and appeared to decline for both lesser and greater retinal thicknesses. By linear regression, the decline in acuity for decreasing retinal thickness was steeper in eyes with an absent third high-reflectance band than for eyes with a partially distinct band. No decline was noted in eyes with an intact band. Assessment of intervisit variability of retinal thickness measurements showed 98% confidence limits of +/-17 microm at fixation and +/-11 microm for the central 1 mm. CONCLUSIONS: Both retinal thinning (due to cell loss) and retinal thickening (due to presumed edema) appear to be associated with lower visual acuity in patients with typical retinitis pigmentosa. The definition of the OCT third high-reflectance band may help to predict which patients are more likely to lose visual acuity as retinal thickness declines. An increase or decrease in retinal thickness of more than 17 microm at fixation or 11 microm over the central 1 mm at follow-up can be considered a significant (P < 0.01) change in these patients.     

Optical coherence tomography analysis of bilateral end-stage choroidal neovascularization where one eye is treated with photodynamic therapy

BACKGROUND: To compare retinal thickness and subretinal hyper-reflectivity using Stratus optical coherence tomography (OCT3) between the eyes of patients with bilateral end-stage exudative age-related macular degeneration (AMD), where one eye has been treated with photodynamic therapy (PDT). METHODS: Patients with PDT-treated stable choroidal neovascularization (CNV), defined as a fibrotic lesion not requiring treatment for 6 months, in one eye and an untreated end-stage CNV (disciform) scar in their fellow eye, underwent refraction protocol logMAR visual acuity (VA) in letters, slit-lamp biomicroscopy, fluorescein angiography and OCT3 scan. Subretinal scar thickness was measured as Outer High Reflectivity Band Thickness (OHRBT) and retinal thickness as neuroretinal foveal thickness (NFT) on OCT3. RESULTS: Thirty-two eyes of 16 patients were studied. Mean OHRBT was 255.62 microm in treated eyes and 350.8 microm in untreated eyes (P = 0.001). Mean NFT was 130.3 microm in the treated eye and 79.9 microm in the untreated eye (P = 0.017). Mean VA was 42 letters in treated eyes and 15 letters in untreated eyes (P < 0.005). CONCLUSION: Based on OCT3 findings, eyes with AMD treated with PDT have a thinner fibrous scar and better preserved retinal thickness when compared with untreated fellow eyes with end-stage fibrotic scarring.     

Fundus microperimetry patterns of fixation in type 2 diabetic patients with diffuse macular edema

BACKGROUND: Recently developed fundus microperimetry (MP-1; Nidek Technologies, Srl. Vigonza PD, Italy) was used to evaluate fixation patterns and retinal sensitivity in patients who had clinically significant macular edema with a diffuse pattern and type 2 diabetes mellitus. METHODS: In a prospective, observational case series study, 84 consecutive patients with type 2 diabetes (84 eyes) who had clinically significant macular edema with a diffuse pattern were studied by means of MP-1. Main outcome measures were fixation stability and position and mean retinal sensitivities within the central 2 degrees and 8 degrees areas. Logarithm of the minimum angle of resolution (logMAR) best-corrected visual acuity (BCVA) was evaluated by means of an Early Treatment of Diabetic Retinopathy Study chart. Foveal thickness was measured by Stratus optical coherence tomography (OCT; Carl Zeiss Meditec, Inc., Dublin, CA). Age, duration of diabetes, hemoglobin A1c (HbA1c) levels, duration of symptoms, history of panretinal photocoagulation, vitreomacular adhesion, and cystoid macular changes were documented. Patients were grouped according to both position of fixation (central or eccentric) and stability of fixation (stable or unstable). Statistical analyses included independent samples t-test, binomial test, Bonferroni correction for multiple comparisons, and generalized linear model univariate analysis. RESULTS: Of 84 eyes, 44 (52.4%) had central fixation, and 40 (47.6%) had eccentric fixation. Of 84 eyes, 34 (40.5%) had stable fixation, and 50 (59.5%) had unstable fixation. In the whole sample, mean central 2 degrees retinal sensitivity +/- SD was 6.26 +/- 3.19 dB (range, 0-14.80 dB), and mean central 8 degrees retinal sensitivity +/- SD was 7.62 +/- 2.55 (range, 3.85-14.90 dB); logMAR BCVA ranged from 0.1 to 1.3 (mean +/- SD, 0.6 +/- 0.29). Mean OCT foveal thickness +/- SD was 300.77 +/- 66.93 m (range, 220-525 m). Both comparisons between groups (stable vs. unstable and central vs. eccentric) showed statistically significant differences in mean logMAR BCVA, mean central 2 degrees and 8 degrees retinal sensitivities, and mean OCT foveal thickness. Duration of symptoms was significantly longer and HbA1c levels were higher in the groups with deterioration of stability or centrality of fixation. The prevalence of cystoid macular changes was significantly higher in the groups with eccentric or unstable fixation (P < 0.001). Generalized linear model statistical analysis showed that logMAR BCVA was significantly associated with stability of fixation (P = 0.020), mean central 8 degrees retinal sensitivity (P < 0.001), and mean OCT foveal thickness (P < 0.001). The interaction between stability of fixation and mean OCT foveal thickness showed a statistically significant association with logMAR BCVA (P = 0.003). Some eyes with eccentric fixation presented with stable fixation, especially in the presence of long-lasting symptoms, and had better visual acuity than eyes with central, but unstable fixation. CONCLUSION: Visual acuity, central retinal sensitivity, foveal thickness, duration of symptoms, HbA1c levels, and presence of cystoid macular changes were strongly associated with fixation impairment in type 2 diabetic patients who had clinically significant macular edema with a diffuse pattern. Stability of fixation and foveal thickness play a major role in conditioning BCVA.     

Characterization of macular edema from various etiologies by optical coherence tomography

PURPOSE: To use optical coherence tomography (OCT) to characterize the intraretinal changes associated with macular edema (ME) according to its etiology. DESIGN: Observational case series. METHODS: Seventy-eight eyes of 78 patients with ME were examined retrospectively by OCT, using the Humphrey 2000 OCT system (Humphrey Co., San Leandro, California). ME etiologies were diabetic retinopathy (27 cases), central retinal vein occlusion (18 cases), pseudophakia (15 cases), posterior uveitis (10 cases), and retinitis pigmentosa (eight cases). Macular thickness was measured using OCT mapping software. It was correlated with logarithmic visual acuity. RESULTS: In 72 of 78 cases (92%), ME was located in the outer retinal layers. Serous retinal detachment was present in 29 of 78 cases (37%). It was most frequent in central retinal vein occlusion (10 of 18 cases, 56%). There were no significant differences in visual acuity (P = .26) or macular thickness (P = .95) whether or not serous retinal detachment was combined with ME. The posterior hyaloid was partially detached in 17 of 78 cases (22%) of overall cases. Serous retinal detachment did not correlate with partial posterior hyaloid detachment (P = .6). Mean macular thickness ranged from 506 microm in central retinal vein occlusion to 373 microm in retinitis pigmentosa. Visual acuity correlated with macular thickness in diabetic retinopathy (R = 0.55; P = .0027) and pseudophakia cases (R = 0.66; P = .016). CONCLUSIONS: OCT characterized the retinal morphologic changes associated with ME, especially the vitreomacular relationship and sub-clinical serous macular detachment. This detachment did not correlate with poor visual acuity. Macular thickening only correlated with visual loss in diabetic retinopathy and pseudophakia.     

光学相干断层成像术观察超声乳化白内障吸除术后黄斑变化

目的　探讨超声乳化白内障吸除术后黄斑形态的变化及其可能的影响因素。方法　对行超声乳化白内障吸除术 ,且术前无合并症、术中无并发症发生的单纯老年性白内障患者 80例 (80只眼 )于术前和术后 1周分别行光学相干断层成像术 (opticalcoherencetomography ,OCT)检查 ;按术中使用的超声能量高低分成 2个组。观察黄斑中心凹视网膜厚度的变化及其与术中超声能量、术后前房炎性反应和视力的关系。结果　 80只眼黄斑中心凹视网膜平均厚度术前为 (14 2 9± 16 7) μm ,术后为 (15 7 9± 36 7) μm ,两者比较差异无显著意义 (P >0 0 5 )。术后 3只眼出现黄斑水肿 ,11只眼出现房水中度闪光 ,黄斑中心凹视网膜平均厚度术前为 (139 9± 11 3) μm ,术后为 (197 6± 36 9) μm ,两者比较差异有显著意义 (t =2 75 1,P <0 0 5 )。低能量组术后黄斑中心凹视网膜平均厚度为 (15 6 2± 18 3) μm ,高能量组为 (172 6± 32 9) μm ,两者比较差异有显著意义 (t=2 4 11,P <0 0 5 )。术后最佳矫正视力与黄斑中心凹视网膜厚度呈负相关性 (r=- 0 82 ,P <0 0 5 )。结论　超声乳化白内障吸除术可导致术眼黄斑中心凹视网膜厚度增加及黄斑水肿 ;术中高超声能量可明显影响术后黄斑中心凹视网膜的形态 ;术后黄斑中心     

Vascular endothelial growth factor is a critical stimulus for diabetic macular edema

PURPOSE: The role of vascular endothelial growth factor (VEGF) in diabetic macular edema (DME) was tested with ranibizumab, a specific antagonist of VEGF. DESIGN: A nonrandomized clinical trial. METHODS: Ten patients with chronic DME received intraocular injections of 0.5 mg of ranibizumab at baseline and at one, two, four, and six months. The primary outcome was change in foveal thickness between baseline and seven months, and the secondary outcome measures were changes from baseline in visual acuity and macular volume. RESULTS: Mean values at baseline were 503 microm for foveal thickness, 9.22 mm3 for macular volume, and 28.1 letters (20/80) read on an Early Treatment Diabetic Retinopathy Study (ETDRS) visual acuity chart. At seven months (one month after the fifth injection), the mean foveal thickness was 257 microm, which was a reduction of 246 microm (85% of the excess foveal thickness present at baseline; P = .005 by Wilcoxon signed-rank test for likelihood that this change is due to ranibizumab rather than chance). The macular volume was 7.47 mm3, which was a reduction of 1.75 mm3 (77% of the excess macular volume at baseline; P = .009). Mean visual acuity was 40.4 letters (20/40), which was an improvement of 12.3 letters (P = .005). The injections were well-tolerated with no ocular or systemic adverse events. CONCLUSION: Intraocular injections of ranibizumab significantly reduced foveal thickness and improved visual acuity in 10 patients with DME, which demonstrated that VEGF is an important therapeutic target for DME. A randomized, controlled, double-masked trial is needed to test whether intraocular injections of ranibizumab provide long-term benefit to patients with DME.     

Spontaneous resolution of vitreomacular traction associated with diabetic macular edema

PURPOSE: Little information is available about the natural history of vitreomacular traction (VMT) associated with diabetic macular edema. A few cases of spontaneous resolution of VMT associated with diabetic macular edema have been described, but have not been documented by optical coherence tomography (OCT). The authors report the spontaneous resolution of VMT associated with diabetic macular edema 1 month after the end of panretinal photocoagulation therapy (PRP). METHODS: Case report: A 66-year-old woman presented with complicated proliferative diabetic retinopathy and diabetic macular edema associated with VMT, documented by OCT, in the right eye. Left eye examination showed complete PRP and ischemic maculopathy. PRP was immediately realized in the right eye in regard to the presence of complicated proliferative diabetic retinopathy. RESULTS: One month after the end of PRP, right eye visual acuity improved. OCT examination showed complete release of foveal posterior hyaloid traction, and significant reduction in foveal thickness. The follow-up was 1 year. At the end of follow-up, visual acuity slightly improved again; only a small residual foveal retinal thickening remained. CONCLUSIONS: The authors report spontaneous resolution of VMT associated with diabetic macular edema, probably facilitated by PRP, with concurrent reduction of macular thickness and visual improvement. As spontaneous resolution may occur in some eyes with diabetic macular edema associated with VMT, a period of observation after the end of the PRP may be considered prior to vitrectomy.     

The status of diabetic retinopathy and diabetic macular edema in patients with type 2 diabetes: a survey from Beixinjing District of Shanghai city in China

Diabetic macular edema (DME) is the major cause of vision loss in patients with diabetic retinopathy (DR). The purpose of this study was to assess the prevalence of DR and DME in a community in China and to analyze the characteristics of their optical coherence tomography (OCT) images. This study was an incidence survey based on data from 108,132 residents living in the Beixinjing District, Shanghai, China. Patients with DME came from the local health network. OCT was performed in 151 eyes of 100 type 2 diabetes patients with DR and 102 eyes of normal control subjects. Totally 795 cases were examined, and 215 of them were diagnosed to have DR. The average thickness of the macular fovea was 195.56 microm in 151 eyes from 100 random samples. Forty-six eyes had macular thickening. The statistical analysis showed that there was a positive correlation between the thickness of the macular fovea and -log of best-corrected visual acuity (r = 0.2869, p = 0.0004) as well as the severity of DR (p = 0.0003). However, there was no statistical significance between DME and posterior vitreous detachment. The images of OCT in DME included 3 types. Best-corrected visual acuity moderately correlated with retinal thickness. The macular thickness correlated with the severity of DR but not with posterior vitreous detachment.