Optical coherence tomographic patterns of diabetic macular edema

Plasma kallikrein and diabetic macular edema

Recent proteomic studies have identified components of the kallikrein kinin system, including plasma kallikrein, factor XII, and kininogen, in vitreous obtained from individuals with advanced diabetic retinopathy. In rodent models, activation of plasma kallikrein in vitreous increases retinal vascular permeability; whereas inhibition of the kallikrein kinin system reduces retinal leakage induced by diabetes and hypertension. These findings suggest that intraocular activation of the plasma kallikrein pathway may contribute to excessive retinal vascular permeability that can lead to diabetic macular edema. The kallikrein kinin system contains two separate and independently regulated serine proteases that generate bradykinin peptides: plasma kallikrein and tissue kallikrein. Tissue kallikrein is expressed in the retina and ciliary body, where it has been implicated in exerting autocrine or paracrine effects via bradykinin receptors that are colocalized in these tissues. Emerging evidence suggests that plasma kallikrein inhibitors may provide a new therapeutic opportunity to reduce retinal vascular permeability.

Statistics of optical coherence tomography data from human retina

Optical coherence tomography (OCT) has recently become one of the primary methods for noninvasive probing of the human retina. The pseudoimage formed by OCT (the so-called B-scan) varies probabilistically across pixels due to complexities in the measurement technique. Hence, sensitive automatic procedures of diagnosis using OCT may exploit statistical analysis of the spatial distribution of reflectance. In this paper, we perform a statistical study of retinal OCT data. We find that the stretched exponential probability density function can model well the distribution of intensities in OCT pseudoimages. Moreover, we show a small, but significant correlation between neighbor pixels when measuring OCT intensities with pixels of about 5 microm. We then develop a simple joint probability model for the OCT data consistent with known retinal features. This model fits well the stretched exponential distribution of intensities and their spatial correlation. In normal retinas, fit parameters of this model are relatively constant along retinal layers, but varies across layers. However, in retinas with diabetic retinopathy, large spikes of parameter modulation interrupt the constancy within layers, exactly where pathologies are visible. We argue that these results give hope for improvement in statistical pathology-detection methods even when the disease is in its early stages.

Pretreatment clinical variables associated with the response to intravitreal bevacizumab (Avastin) injection in patients with persistent diabetic macular edema

BACKGROUND

The purpose of the study is to determine whether the pre-treatment clinical systemic variables and optical coherence tomography (OCT) findings are associated with the subsequent response to the intravitreal bevacizumab (IVB) in eyes with persistent diabetic macular edema (DME).

DESIGN

Prospective, interventional non-comparative case series study.

METHODS

38 Patients (45 eyes) with refractory diabetic macular edema; 16 females, 22 males with a mean aged 57.5 year. All patients had persistent DME not responded to other forms of treatments. Complete eye examination; best corrected visual acuity (BCVA) (represented as LOGMAR for adequate statistical analysis), slit-lamp exam, intraocular pressure measurement, stereoscopic biomicroscopy of the macula, and morphologic patterns of diabetic macular edema demonstrated by OCT. All patients had intravitreal injection of 0.05 mL = 1.25 mg bevacizumab (Avastin; Genentech, Inc., San Francisco, CA), and were followed up for 3 months. The pre and post-injection follow-up data were analyzed by Student-t test and Mann-Whitney test for two main outcome measures; visual acuity (LOGMAR) and central foveal thickness (CFT) changes over a period of three months, and the data included demographic factors, type, duration and the control of diabetes mellitus (HbA1C%), grade of diabetic retinopathy, renal function (serum creatinine level), serum cholesterol, blood pressure control and previous treatment by focal laser and/or intravitreal triamcinolone injection.

RESULTS

The LOGMAR and central foveal thickness (CRT) improved in 30/45 eyes (67%) and 32/45 eyes (72%), respectively during a mean follow-up time of three months. The mean LOGMAR visual acuities were 0.64 (SD ± 0.34), 0.61 (SD ± 0.31) and 0.60 (SD ± 0.32) at pre-injection, at 1 month post-injection and at 3 months post-injection, respectively; but this mean increase in vision was statistically not significant (P value = 0.099). The mean foveal thicknesses were 444.95 μm (SD ± 127.36), 394.95 μm (SD ± 138.03) and 378.32 μm (SD ± 112.01) at pre-injection, 1 month post-injection and 3 months post-injection, respectively, this decrease in the foveal thickness was statistically significant (P value <0.001). The pre and post-injections values of the variables for diabetic duration, diabetic control (HbA1c) and OCT pattern of macular edema showed significant statistical correlations (P < 0.05) with LOGMAR only, however the values of the variables for serum creatinine and cholesterol show statistical correlation (P < 0.05) with both LOGMAR and CFT.

CONCLUSIONS

Chronicity and inadequate control of diabetes mellitus, nephropathy, hyperlipidemia and presence of vitreomacular attachment (VMA) are factors associated with poor vision progress after intravitreal bevacizumab injection.

Imaging chorioretinal vascular disease

Since its first description more than 40 years ago, fluorescein angiography had a crucial role in the diagnosis and management of chorioretinal vascular disorders such as neovascular age-related macular degeneration. Although fluorescein angiography permits visualization of the retinal microcirculation in exquisite detail, visualization of the choroidal circulation is more limited. Moreover, fluorescein angiography provides only minimal information regarding the functional consequences of vascular disease and allows, at best, only semi-quantitative assessment of retinal thickness. In recent years, the development of other chorioretinal imaging modalities, such as indocyanine green angiography, fundus autofluorescence, and optical coherence tomography (OCT), has addressed many of these issues. In particular, OCT has become an integral tool for vitreoretinal specialists as it allows high-resolution cross-sectional images of the neurosensory retina to be obtained in a non-invasive manner. The latest generation of commercial OCT technology-spectral domain OCT-offers high-speed scanning that allows complete coverage of the macular area, generation of three-dimensional retinal reconstructions, and precise image registration for inter-visit comparisons. The high speed of spectral domain OCT also facilitates B-scan averaging, which reduces speckle noise artefact and allows unparalleled visualization of the outer retina and choroid. In the near future, further advances in OCT technology (eg Doppler OCT) are likely to dramatically enhance the diagnosis and management of patients with chorioretinal vascular disease.

Intravitreal ranibizumab (Lucentis) for treatment of central retinal vein occlusion: a prospective study

BACKGROUND/PURPOSE

To evaluate the effect of individualized repeated intravitreal injections of ranibizumab (Lucentis) on visual acuity (VA) and central foveal thickness (CFT) for central retinal vein occlusion (CRVO)-induced macular edema.

METHODS

Our study was a prospective interventional case series. Twelve eyes of 12 consecutive patients diagnosed with CRVO-related macular edema (nine perfused, three ischemic CRVO) treated with repeated (when CFT was >220 microm) intravitreal injections of ranibizumab as a monotherapy within 3 months of onset were evaluated. Optical coherence tomography (OCT) and fluorescein angiography (FA) were performed monthly and every 3 months respectively. Changes in VA (ETDRS) and CFT were analyzed using the student's paired t-test.

RESULTS

The mean time from diagnosis until injection was 80 days (2.7 months; range, 63-90 days) and the follow-up time was 12 months. In total, 89 injections were performed (mean 7.4). The mean CFT improved from 480 +/- 166 microm at baseline to 230 +/- 33 microm (P < 0.001) at the end of the follow-up. During the same period, of the 12 eyes, eight demonstrated improved VA (>0.3 LogMAR change, >15 letters), three stable VA and one worse VA as compared to baseline. None of the nine patients with perfused CRVO were converted to ischemic at 12 months, and one of the three eyes with ischemic CRVO developed iris neovascularization despite two ranibizumab injections. No ocular or systemic side-effects were noted.

CONCLUSION

Individualized repeated intravitreal injections of ranibizumab have shown promising results in VA improvement and decrease in CFT in patients with macular edema associated with CRVO. Further studies are needed in order to elucidate the role of intravitreal lucentis in the ischemic form of CRVO, and its efficacy in preventing conversion from the perfused to the ischemic form of the disease.

Assessment of serous macular detachment in eyes with diabetic macular edema by use of spectral-domain optical coherence tomography

BACKGROUND

The introduction of optical coherence tomography (OCT) has brought new potentialities for an objective evaluation of macular diseases. The purpose of the present study was to assess the serous macular detachment (SMD) in eyes with diabetic macular edema (DME) by use of spectral-domain OCT.

METHODS

In this prospective study were included 79 eyes of 46 patients with diabetic retinopathy and DME. All patients underwent examination of best-corrected visual acuity (BCVA), non-contact slit-lamp fundus biomicroscopy, fluorescein angiography and OCT. Spectral-domain OCT (OCT/SLO Combination Imaging System, OPKO/OT Inc., Toronto, Ontario, Canada) was used to evaluate retinal morphology and the presence of macular traction (vitreomacular and/or from epiretinal membranes) on B-scans, C-scans and C-scan OCT/SLO fundus image overlays. With OCT were measured retinal thickness, volume, diameter of intraretinal cystoid spaces, diameter and height of SMD. The correlation of retinal thickness and volume with BCVA in all eyes with DME and the relation of SMD to retinal thickness, volume, BCVA, macular traction and ischemia were assessed.

RESULTS

The SMD was diagnosed only by means of OCT in nine eyes (11.4%) of five patients. In eight of nine eyes it was combined with intermediate (300-600 microm) or severe (>600 microm) cystoid spaces, and in one eye with simple macular edema. Retinal thickness and volume correlated with BCVA (r = 0.464, P < 0.0001 and r = 0.480, P < 0.0001). The SMD height did not correlate with retinal thickness, volume or BCVA. Six eyes with SMD had macular ischemia, and five eyes had severe ischemia in retinal periphery. Macular traction was: absent in three eyes, questionable (without distortion of retinal contour from partial posterior vitreous detachment and/or epiretinal membrane) in three eyes, and definite (with distortion of retinal contour) in three eyes.

CONCLUSIONS

Spectral-domain OCT provided valuable information on retinal morphology and was particularly useful in diagnosing sub-clinical SMD in eyes with DME. It disclosed the presence and strength of macular traction either by partially detached posterior hyaloid or by epiretinal membranes. C-scans and C-scan OCT/SLO fundus image overlays added complementary information for the extent and location of the pathological features. Larger studies which follow subjects longitudinally are needed to explain the pathogenesis and determine the prognosis of SMD.

Serous macular detachment as a predictor of resolution of macular edema with intravitreal triamcinolone injection

BACKGROUND AND OBJECTIVE

To evaluate serous macular detachment as a predictor for response of macular edema to intravitreal triamcinolone acetonide.

PATIENTS AND METHODS

Sixteen eyes (16 patients) with macular edema and serous macular detachment secondary to diabetic retinopathy (n = 11) or branch vein occlusion (n = 5) were prospectively enrolled. After intravitreal triamcinolone acetonide injection (4 mg/0.1 mL), they were reevaluated at 1 week and 1 and 3 months. The main outcome measure was change in central macular thickness.

RESULTS

The mean baseline central macular thickness was 651.13 +/- 245.96 microm. One month after intravitreal triamcinolone acetonide injection, central macular thickness decreased to 255.38 +/- 80.64 microm (P < .0001). After 3 months, central macular thickness increased marginally to 329.69 +/- 161.98 microm, still significantly less than baseline (P < .0001). There was a significant correlation between the height of serous macular detachment and reduction in central macular thickness at 1 (r = .827) and 3 (r = .835) months (P< .0001).

CONCLUSION

When serous macular detachment coexists with vascular or microvascular macular edema, it responds to intravitreal triamcinolone acetonide in direct proportion to the height of the serous macular detachment. However, the response begins to fade by 3 months.

Relationship between optical coherence tomography retinal parameters and visual acuity in neovascular age-related macular degeneration

PURPOSE

To investigate the relationship between optical coherence tomography (OCT)-derived measurements of retinal morphology and visual acuity in patients with neovascular age-related macular degeneration (AMD).

DESIGN

Retrospective cross-sectional study.

PARTICIPANTS

A total of 216 consecutive patients (216 eyes) newly diagnosed with neovascular AMD who underwent StratusOCT imaging at the time of diagnosis.

METHODS

Best-corrected Snellen visual acuity was recorded for each patient. Raw exported StratusOCT images for each patient were analyzed using publicly available custom software entitled "OCTOR," which allows the precise positioning of prespecified boundaries on individual B-scans. Thickness and volume were calculated for morphologic parameters of interest: neurosensory retina, subretinal fluid, subretinal tissue (SRT), and pigment epithelial detachment.

MAIN OUTCOME MEASURES

OCT-derived measurements of retinal morphology and visual acuity.

RESULTS

An increased total volume of SRT was correlated with decreased visual acuity (r = 0.370, P<0.0001). Decreased visual acuity was also modestly correlated with increased thickness of the neurosensory retina at the foveal center point (r = 0.245, P = 0.0004). No statistically significant association was detected between visual acuity and the total volume of subretinal fluid or pigment epithelial detachment. The association between visual acuity and both the neurosensory retina and the SRT was stronger for lesions classified as minimally classic or occult on fluorescein angiography. For occult lesions, 20% of the variation in visual acuity could be predicted by a multiple regression model that incorporated age and SRT volume, whereas, for minimally classic lesions, 62% of the variation in visual acuity could be predicted by a multiple regression model that incorporated age, total neurosensory retinal volume, and total SRT volume.

CONCLUSIONS

The presence of increased SRT thickness and volume on OCT, and to a lesser extent increased neurosensory retinal thickness and volume, is associated with decreased visual acuity in neovascular AMD. However, because of the complex pathophysiology of neovascular AMD and, in part, the limitations of StratusOCT, these factors only account for a small degree of the variation in visual acuity that these patients exhibit. The detection of stronger correlations between retinal anatomy and visual acuity is likely to require the use of more advanced imaging modalities.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Diabetic macular edema: what is focal and what is diffuse?

PURPOSE

To review the available information on classification of diabetic macular edema (DME) as focal or diffuse.

DESIGN

Interpretive essay.

METHODS

Literature review and interpretation.

RESULTS

The terms focal diabetic macular edema and diffuse diabetic macular edema frequently are used without clear definitions. Published definitions often use different examination methods and often are inconsistent. Evaluating published information on the prevalence of focal and diffuse DME, the responses of focal and diffuse DME to treatments, and the importance of focal and diffuse DME in assessing prognosis is hindered because the terms are used inconsistently. A newer vocabulary may be more constructive, one that describes discrete components of the concepts such as extent and location of macular thickening, involvement of the center of the macula, quantity and pattern of lipid exudates, source of fluorescein leakage, and regional variation in macular thickening and that distinguishes these terms from the use of the term focal when describing one type of photocoagulation technique. Developing methods for assessing component variables that can be used in clinical practice and establishing reproducibility of the methods are important tasks.

CONCLUSIONS

Little evidence exists that characteristics of DME described by the terms focal and diffuse help to explain variation in visual acuity or response to treatment. It is unresolved whether a concept of focal and diffuse DME will prove clinically useful despite frequent use of the terms when describing management of DME. Further studies to address the issues are needed.

Optical coherence tomography features during the evolution of serous retinal detachment in patients with diabetic macular edema

PURPOSE

To characterize the evolution of serous retinal detachment (SRD) combined with diabetic macular edema (DME) using optical coherence tomography (OCT).

DESIGN

Observational retrospective case series.

METHODS

In our institution, 64 eyes of 40 diabetic patients who had SRD combined with DME were studied. All patients had fluorescein angiography and several OCT3 examinations during follow-up. Foveolar neuroretinal thickness (NRT) and SRD height were measured. The evolution of OCT macular profiles was qualitatively assessed.

RESULTS

Mean follow-up was 11.8 months. DME was focal in 10 eyes (15.6%), diffuse in 17 (26.6%) and both diffuse and focal in 37 (57.8%). Mean initial decimal visual acuity (VA), NRT, and SRD height (+/- standard deviation) were 0.35 +/- 0.21, 346.88 +/- 138.61 and 199.48 +/- 139.8 microm, respectively. SRD height did not correlate with VA (P = .23) or NRT (P = .31). In 13 eyes (20.3%), NRT above the SRD was normal. In the 19 eyes where DME improved during follow-up, SRD disappeared before the maximal reduction of retinal thickness in seven eyes (36.8%) and after or simultaneously with this reduction, in 12 eyes (63.2%). Among the 45 eyes where DME worsened during follow-up, SRD disappeared from 15 eyes (33.3%).

CONCLUSION

In this series, SRD height did not correlate with retinal thickening. The latter may appear before central neuroretinal thickening and disappear before or after its regression. Consequently, SRD does not seem to be related either to the severity of DME or to its resorption.

Clinical and optical coherence tomographic findings and outcome of treatment in patients with presumed tuberculous uveitis

PURPOSE

To define the clinical characteristics and optical coherence tomographic (OCT) features, and to assess the outcome of treatment, in patients with presumed tuberculous uveitis (PTU).

METHODS

All patients diagnosed with PTU at King Abdulaziz University Hospital between January 1998 and May 2006 were reviewed. The diagnosis was made when findings were consistent with possible intraocular tuberculosis with no other cause of uveitis suggested by history, symptoms, or ancillary testing, strongly positive tuberculin skin-test results, and response to antituberculous therapy.

RESULTS

Fifty-one patients (73 eyes) were identified. There were 34 males (66.7%) and 17 females (33.3%) with a mean age of 40.1+/-11.0 years (range 16-68 years). Fifty-eight eyes (79.5%) had panuveitis and 15 eyes (20.5%) had posterior uveitis at presentation. Clinical manifestations included vitritis (71.2%), macular edema (63%), retinal periphlebitis (35.6%), multifocal choroiditis (20.5%), and granulomatous anterior uveitis (17.9%). All patients received antituberculous therapy and systemic corticosteroids. After a mean follow-up of 18.9+/-21.9 months (range 6-96 months), all eyes showed resolution of inflammation, with no recurrences, associated with significant improvement in visual acuity (VA) (P=0.007). There was a significant positive correlation between initial and final VAs (r=0.7856, P<0.001). Thirty-one eyes with macular edema were examined at baseline and at follow-up with OCT. There were three patterns of macular edema: diffuse (DME) (28.5%), cystoid (29%), and serous retinal detachment (45.2%). Initial VA of 20/40 or better was significantly associated with central macular thickness (CMT) of 300 microm or less (P=0.0065) and DME (0.0484). At final follow-up, there was a significant reduction in CMT (P<0.001) associated with a significant improvement in VA (P=0.0091).

CONCLUSIONS

Antituberculous therapy combined with systemic corticosteroids leads to resolution of inflammation and elimination of recurrences of PTU. OCT is useful in monitoring the efficacy of treatment in patients with macular edema.

Optical coherence tomography findings in persistent diabetic macular edema: the vitreomacular interface

PURPOSE

To assess the optical coherence tomography (OCT) characteristics of eyes with persistent clinically significant diabetic macular edema (PDME) after focal laser treatment, with emphasis on the vitreomacular interface (VMI) characteristics.

DESIGN

Prospective, observational case series.

METHODS

Fifty eyes with PDME after at least one focal laser treatment were enrolled prospectively. Slit-lamp biomicroscopy, stereoscopic fundus photography, fluorescein angiography (FA), and OCT were performed for each eye. The main outcome measures included the detection rate of VMI abnormalities (VMIA) by OCT in comparison with biomicroscopy, fundus photography, and FA (traditional techniques); the relationship between VMIA and the number of focal laser sessions per eye and FA leakage pattern.

RESULTS

Two of 50 eyes were excluded because of incomplete data. For the remaining 48 eyes, 25 eyes (52.1%) demonstrated definite VMIA, including anomalous vitreal adhesions, epiretinal membrane (ERM), or both, and six eyes (12.5%) had questionable VMIA. OCT in general was 1.94 times more sensitive than traditional techniques combined in detecting VMIA (P = .00003). The number of focal laser sessions and diffuse FA leakage were not associated with an increased prevalence of VMIA (P = .13 and P = .47, respectively).

CONCLUSIONS

This study demonstrates a high prevalence of VMIA in eyes with PDME after focal laser treatment and underscores the superiority of OCT in detecting these abnormalities. OCT evaluation of eyes with PDME may be helpful in identifying VMIA, which may impact treatment selection and patient subgroup stratification.

Anti-VEGF agents in the treatment of neovascular age-related macular degeneration: applying clinical trial results to the treatment of everyday patients

PURPOSE

The vision gains reported with monthly intravitreal ranibizumab in the MARINA and ANCHOR trials led to an immediate paradigm shift in the treatment of neovascular AMD with retina physicians universally switching to the pan-VEGF blocking agents ranibizumab and bevacizumab, and patients expecting visual improvement. As these agents are primarily used on a pro re nata (PRN) dosing schedule (because neither patients nor physicians want monthly injections), the factors involved in making the treatment and retreatment decisions are very important in any attempt to maximize vision gain.

DESIGN

Analysis of literature, ongoing clinical trials, and the clinical assessments that can aid clinicians in treatment and retreatment decisions.

METHODS

Literature review and perspective.

RESULTS

If a monthly injection protocol is not used, clinicians should use both functional and anatomic criteria to attempt to guide treatment and retreatment decisions. Qualitative optical coherence tomography (OCT) appears to be the most sensitive and practical assessment tool to determine anatomic response to treatment but should be used in conjunction with clinical examination.

CONCLUSIONS

If monthly intravitreal injections are not performed, a combination of clinical examination (looking for new hemorrhage) and qualitative OCT (to assess response to treatment and early signs of recurrent leakage) can be used to guide anti-vascular endothelial growth factor (anti-VEGF), treatments with the goal of maintaining a "normal" retinal anatomy in an attempt to maximize the benefit (visual acuity gains) to risk (number of injections required) ratio.

Enhancing the signal-to-noise ratio in ophthalmic optical coherence tomography by image registration--method and clinical examples

Optical coherence tomography (OCT) has already proven an important clinical tool for imaging and diagnosing retinal diseases. Concerning the standard commercial ophthalmic OCT systems, speckle noise is a limiting factor with respect to resolving relevant retinal features. We demonstrate successful suppression of speckle noise from mutually aligning a series of in vivo OCT recordings obtained from the same retinal target using the Stratus system from Humphrey-Zeiss. Our registration technique is able to account for the axial movements experienced during recording as well as small transverse movements of the scan line from one scan to the next. The algorithm is based on a regularized shortest path formulation for a directed graph on a map formed by interimage (B-scan) correlations. The resulting image enhancement typically increases the contrast-to-noise ratio (CNR) with a factor of three or more and facilitates segmentation and quantitative characterization of pathologies. The method is currently successfully being applied by medical doctors in a number of specific retinal case studies.

Enhanced optical coherence patterns of diabetic macular oedema and their correlation with the pathophysiology

PURPOSE

To describe different patterns of diabetic macular oedema (DMO) using a computerized alignment and averaging of sequences in optical coherence tomography (OCT) B-scans and to show the correlation of these patterns with the pathophysiology of the condition.

METHODS

We carried out a prospective, uncontrolled study, including 46 human subjects with untreated DMO. Enhanced OCT images were produced. We correlated different OCT patterns of DMO with ETDRS visual acuity and with the thickness of the central 1-mm of the macula. We also correlated these patterns with theories of the pathophysiology of DMO.

RESULTS

Enhanced OCT images enabled us to examine how different layers of the macula were affected. The external limiting membrane (ELM) was clearly seen in all stages, including advanced stages. The sequence of DMO events in different macular layers can be divided into five patterns. Morphologically, DMO starts at the outer nuclear layer/Henle's layer. As the oedema progresses, cysts are seen in the fovea and the DMO spreads further into the inner nuclear layer. The ELM seems to act as a barrier for proteins and plays an important role in the development of DMO.

CONCLUSIONS

Enhanced OCT revealed new details of DMO pathophysiology. The different morphological patterns of DMO seen in enhanced OCT may represent different levels of severity of the disease.

Predictive factors for short-term visual outcome after intravitreal triamcinolone acetonide injection for diabetic macular oedema: an optical coherence tomography study

AIM

To evaluate the predictive factors for visual outcome after intravitreal triamcinolone acetonide injection to treat refractory diabetic macular oedema (DME).

METHODS

A retrospective chart review of patients with DME who met the following inclusion criteria was performed: clinically significant diabetic macular oedema, receipt of a 4 mg/0.1 ml intravitreal triamcinolone acetonide injection and an optical coherence tomography (OCT) of the macula performed up to 10 days before injection. All patients received a full ophthalmic examination including best-corrected Snellen visual acuity (VA). The main outcome measure was the mean change in vision 3 months after injection.

RESULTS

Data from 73 eyes of 59 patients were analysed. After a mean follow-up of 324 days, the mean change in vision was -0.075 logarithm of minimum angle of resolution (logMAR) units, with 27.3% improving > or =3 lines, 6.8% declining > or =3 lines and 60.2% remaining stable within 1 line of baseline vision. Statistical analysis was performed using multivariate generalised estimating equations on the basis of data from 52 eyes of 42 patients. Factors associated with an improvement in vision 3 months after injection were worse baseline VA (-0.27 logMAR units/unit increase in baseline VA, p = 0.002) and presence of subretinal fluid (-0.17 logMAR units, p = 0.06). The presence of cystoid macular oedema negatively affected the visual outcome (0.15 logMAR units, p = 0.03). In addition, the presence of an epiretinal membrane (ERM) was associated with less visual improvement. ERM modified the effect of baseline VA as demonstrated by a significant interaction between these two variables (0.34 logMAR units/unit increase in baseline VA, p = 0.04).

CONCLUSIONS

OCT factors and baseline VA can be useful in predicting the outcomes of VA 3 months after intravitreal triamcinolone acetonide injection in patients with refractory DME.