Impact of optical coherence tomography on surgical decision making for epiretinal membranes and vitreomacular traction

Mechanical impact of epiretinal membranes on the retina utilizing finite element analysis

BACKGROUND AND OBJECTIVE

Epiretinal membrane (ERM) is a transparent membrane that forms on the surface of the neurosensory retina, causing tangential traction on the retinal surface, which may contribute to cell proliferation and contraction. Epiretinal membranes (ERMs) may be asymptomatic in some patients, while in others the membranes can progress, resulting in macular thickening and macular traction, thus distorting and inducing loss of central visual function and metamorphopsia. Currently, treatment options include follow-up or pars plana vitrectomy with an ERM peel, aiming to relieve the macular traction and improve vision and metamorphopsia. No specific criteria exist for predicting which patients might progress and need early surgery to improve and maintain good vision. The decision for surgery is based on the individual's symptoms and the physician's judgment. This study aimed to evaluate the mechanical impact in terms of stress and deformations of the ERM and to qualitatively compare them with the clinical progression of fovea thickening observed through optical coherence tomography (OCT) images.

METHODS

Numerical simulation on a three-dimensional geometrical retina and ERM model was applied to isolate factors that can be used to predict its progression and prognosis. OCT images of 14 patients with ERM were used to derive the fovea thickness progression before and after vitrectomy surgery with ERM peeling.

RESULTS

The results clearly show that the increase in ERM contractility level increases the developed stress at the fovea, which spreads and advances toward its base. The highest stress level (2.1 kPa) was developed at the highest and asymmetric contractility, producing non-uniform distributed deformations that distort the fovea structure.

CONCLUSIONS

These findings imply that high and asymmetric ERM contractility should be evaluated clinically as a factor that might signal the need for early vitrectomy surgery to avoid irreversible visual loss. Moreover, the OCT images revealed that in some cases, the thickness of the fovea indeed remains high, even after ∼12 months postoperatively, which also indicates that the deformation of the fovea in these cases is irreversible.

Optical Coherence Tomography: Focus on the Pathology of Macula in Scleritis Patients

Optical coherence tomography (OCT) is a non-invasive imaging technique for high-resolution, cross-sectional tissue imaging of the eye. During the past two and a half decades, OCT has become an essential tool in ophthalmology. It is a painless method for examining details of ocular structures in vivo with high resolution that has revolutionized patient care following and treating scleritis patients.

METHODS

Twenty-four patients diagnosed with scleritis were selected for this study. All of the patients went through basic ophthalmological examinations, such as visual acuity testing (VA), intraocular pressure measurement (IOP), slit lamp examination, ophthalmoscopic examination, and OCT. OCT examinations were taken by SD-OCT Spectralis OCT system (Heidelberg Engineering, Heidelberg, Germany).

RESULTS

Twenty-seven eyes of 24 patients (7 males and 17 females) were included in this study, who were diagnosed with scleritis. OCT examinations showed epiretinal membrane (ERM) in three patients (12%), cystoid macular edema (CME) (three cases, 12%), diffuse macular edema (DME) (one case, 4%), and serous retinal detachment (SRD) (one case, 4%).

CONCLUSIONS

OCT proved to be a valuable, non-invasive method for detecting macular pathology in patients with scleritis. Despite the best treatment regimen applied, macular involvement resulting in reduced visual acuity (VA) can develop, which we could detect with OCT since macular edema (ME) is the leading cause of decreased vision due to the damaged outer blood-retina barrier (BRB) in inflammation. OCT investigation is a highly important method for early detection of ocular complications in scleritis in order to prevent blindness.

Macular optical coherence tomography for screening of pathology prior to cataract surgery: An approach based on tele-evaluation

BACKGROUND

To assess the benefit of macular spectral-domain optical coherence tomography (SD-OCT) as a part of the routinary preoperative study of patients undergoing cataract surgery.

METHODS

A prospective single-center study study was performed. Consecutive patients with normal biomicroscopic funduscopy, moderate cataract and no history of ophthalmological pathologies were enrolled. All patients underwent macular SD-OCT. The obtained images were analysed by a general ophthalmologist and two retina specialists. Incidence of macular pathology and its relation to age and comorbidities were assessed.

RESULTS

Eight-hundred and thirty-six eyes of 419 patients were enrolled in this study. All images were analysed telematically by a general ophthalmologist. Forty-nine eyes were excluded due to insufficient quality of the obtained images. Abnormal images were observed in 156 eyes (18.6%), including age-related macular degeneration in 68 (8.2%), epiretinal membrane (ERM) in 67 (8.0%), cystoid macular edema in 3 eyes (0.4%), among others. Diagnostics with severe impact on patient visual prognosis were observed in 16 eyes (3.82%) from 12 patients. The relationship between incidence of macular pathologies and age or comorbidities was not statistically significant. To assess accuracy of the first observer, images were subsequently analysed by two retinologists. The kappa index of concordance was 0.80 and 0.85.

CONCLUSIONS

Implementing a systematic macular SD-OCT as a preoperative test prior to cataract surgery would improve quality of postoperative visual prognosis information. A general ophthalmologist would be suitable to screen for pathology through macular OCT images.

Challenges in Diabetic Macular Edema Management: An Expert Consensus Report

Purpose

This paper aimed to present daily-practice recommendations for the management of diabetic macular edema (DME) patients based on available scientific evidence and the clinical experience of the consensus panel.

Methods

A group of Spanish retina experts agreed to discuss different aspects related with the clinical management of DME patients.

Results

Panel was mainly focused on therapeutic objectives in DME management; definition terms; and role of biomarkers as prognostic and predictive factors to intravitreal treatment response. The panel recommends to start DME treatment as soon as possible in those eyes with a visual acuity less than 20/25 (always according to the retina unit capacity). Naïve patient was defined, in a strict manner, as a patient who, up to that moment, had never received any treatment. A refractory DME patient may be defined as the one who did not achieve a complete resolution of the disease, regardless of the treatment administered. Different optical coherence tomography biomarkers, such as disorganization of the retinal inner layers, hyperreflective dots, and cysts, have been identified as prognostic factors.

Conclusion

This document has sought to lay down a set of recommendations and to identify key issues that may be useful for the daily management of DME patients.

[Study of vitreomacular interface in patients with pseudophakia by means of spectral optical coherence tomography]

AIM

to investigate the state of vitreomacular interface in pseudophakic patients by means of spectral optical coherence tomography (OCT).

MATERIAL AND METHODS

Spectral OCT of the macular region was performed in 58 pseudophakic eyes that underwent laser treatment for secondary cataract, 28 newly pseudophakic eyes (day 1 after cataract phacoemulsification with IOL implantation), and 40 eyes with early senile cataract.

RESULTS

A higher incidence of subclinical fibrosis of the internal limiting membrane was noted in pseudophakic patients after YAG laser surgery for secondary cataract as compared to cataract patients and those right after cataract phacoemulsification.

CONCLUSION

Fibrosis of the internal limiting membrane significantly more often develops in the late period after cataract extraction as compared to patients with early senile cataract and those who have just underwent phacoemulsification surgery. Fibrosis of the internal limiting membrane arising in the late period after cataract extraction cannot be unambiguously attributed to either primary or secondary. The resolution of spectral OCT is high enough to allow detection of preclinical ultrastructural changes in the vitreomacular interface.

Prevalence of vitreomacular adhesion: an optical coherence tomography analysis in the retina clinic setting

Purpose

The aims of this study were to determine the prevalence of vitreomacular adhesion (VMA) in a random sample of clinical patients at three US retina clinics and to assess comorbid retinal conditions, ocular diseases, prior treatment history, and other medical histories.

Patients and methods

This observational, retrospective cohort study was based on patients from the Doheny Eye Centers, Duke Eye Center, and Tufts Medical Center who received a bilateral spectral domain optical coherence tomography (SD-OCT) scan (one scan/eye) for clinical evaluation with available medical records. The study had three phases: 1) collection of retrospective patient data; 2) review of OCT scans at a reading center to assess VMA and associated conditions; and 3) analyses and reporting of data on the prevalence of VMA, patient demographics, and comorbid conditions. Data were obtained from electronic health records and OCT grading forms. Outcome measures from bilateral SD-OCT scans and medical records included OCT evaluation of VMA and retinal comorbid conditions.

Results

In 719 patients with 1,483 reviewable OCT scans, the prevalence of VMA was estimated at 14.74% (90% CI, 12.58%–16.92%). The prevalence of unilateral VMA was estimated at 12.39%, while bilateral VMA was 2.36%. In patients with VMA, 34 out of 123 eyes with VMA (27.64%) also had fovea deformed by vitreomacular traction. Macular hole (MH) was significantly more prevalent in VMA-diagnosed eyes versus non-VMA-diagnosed eyes (6.5% versus 1.9%; P=0.02). There was a significantly higher incidence of full-thickness MH (P=0.008), operculum/flaps (P<0.0001), and lamellar or pseudo-holes (P=0.048) in VMA-diagnosed versus non-VMA-diagnosed eyes. Age, MH as a comorbid condition, full-thickness MH, lamellar or pseudo-holes, and operculum were predictive of a VMA diagnosis.

Conclusion

The prevalence of VMA was estimated at 14.74% in a random sample of patients from three retina clinics. VMA diagnosis can be predicted by factors, including age, MH as a comorbid condition, and lamellar or pseudo-holes.

The design and validation of an optical coherence tomography-based classification system for focal vitreomacular traction

PURPOSE

To develop and validate a classification system for focal vitreomacular traction (VMT) with and without macular hole based on spectral domain optical coherence tomography (SD-OCT), intended to aid in decision-making and prognostication.

METHODS

A panel of retinal specialists convened to develop this system. A literature review followed by discussion on a wide range of cases formed the basis for the proposed classification. Key features on OCT were identified and analysed for their utility in clinical practice. A final classification was devised based on two sequential, independent validation exercises to improve interobserver variability.

RESULTS

This classification tool pertains to idiopathic focal VMT assessed by a horizontal line scan using SD-OCT. The system uses width (W), interface features (I), foveal shape (S), retinal pigment epithelial changes (P), elevation of vitreous attachment (E), and inner and outer retinal changes (R) to give the acronym WISPERR. Each category is scored hierarchically. Results from the second independent validation exercise indicated a high level of agreement between graders: intraclass correlation ranged from 0.84 to 0.99 for continuous variables and Fleiss' kappa values ranged from 0.76 to 0.95 for categorical variables.

CONCLUSIONS

We present an OCT-based classification system for focal VMT that allows anatomical detail to be scrutinised and scored qualitatively and quantitatively using a simple, pragmatic algorithm, which may be of value in clinical practice as well as in future research studies.

Spectral domain optical coherence tomography characterization of pediatric epiretinal membranes

PURPOSE

To compare the macular morphology of pediatric versus adult eyes with epiretinal membrane (ERM) using spectral domain optical coherence tomography and identify characteristics associated with postoperative visual acuity.

METHODS

This retrospective study analyzed spectral domain optical coherence tomography from pediatric subjects and a randomly selected cohort of adult subjects with ERM. Morphologic retinal and ERM features were graded by two masked spectral domain optical coherence tomography readers and compared with a postoperative change in visual acuity.

RESULTS

Pediatric ERMs (age, 0.3-16.5 years) were more confluently attached to the retina than adult ERMs (age, 40-88 years; P = 0.009) and had less fibrillary appearance of the inner retina when separation was present (P = 0.044). Pediatric ERMs were associated with more vessel dragging (P = 0.019) and less external limiting membrane (P = 0.001) and inner segment band visibility (P = 0.010), with a trend toward foveal sparing by ERM (P = 0.051) and "taco" retinal folds (P = 0.052) compared with adult eyes. Visual acuity improvement was associated with intact (P = 0.048) and smooth (P = 0.055, trend) inner segment band in children and with smooth inner segment band (P = 0.083, trend) and visible external limiting membrane (P = 0.098, trend) in adults.

CONCLUSION

We identified morphologic differences between pediatric and adult ERM on spectral domain optical coherence tomography. Similar to adults, photoreceptor integrity with pediatric ERM seems to predict better visual acuity changes after surgical ERM removal.

Correlation of outer retinal microstucture and foveal thickness with visual acuity after pars plana vitrectomy for complications of proliferative diabetic retinopathy

PURPOSE

To compare spectral domain optical coherence tomography (SDOCT)-measured macular thickness, outer retinal layers architecture, and best-corrected visual acuity (BCVA) in eyes with proliferative diabetic retinopathy after pars plana vitrectomy.

METHODS

In this retrospective case study, consecutive eyes operated by single surgeon were included. Retinal thickness was measured with SDOCT (Cirrus OCT; Carl Zeiss Meditec, Inc) as follows: automated central 1-mm subfield thickness (CFT), manually measured central foveal point thickness (CPT), integrity of external limiting membrane (ELM), and photoreceptor inner and outer segments (IS/OS). Three vitreoretinal-trained masked experts independently graded ELM and IS/OS layers.

RESULTS

Of the 36 eyes included, 50% were those of women whose mean age was 49 years (range, 24-66 years). Mean preoperative BCVA was 20/600 (range, light perception to 20/80) and mean postoperative follow-up was 19 months (range, 4-43 months). Mean postoperative BCVA improved to 20/80 (range, counting fingers to 20/25; P < 0.0001) with mean SDOCT 1 mm CFT of 260 μm and manual CPT of 236 μm. Mean ELM integrity grade was 1.9 (range, 0-5), while the mean grade of IS/OS integrity was 2.2 (range, 0-5). The correlation coefficients (r) were 0.17 (P = 0.32) for logarithm of the minimum angle of resolution BCVA versus SDOCT automated CFT, 0.192 (P = 0.26) for BCVA versus SDOCT CPT, 0.52 (P = 0.012) for BCVA versus ELM, and 0.55 (P = 0.006) for BCVA versus IS/OS.

CONCLUSION

SDOCT-measured CFT and CPT correlate weakly with BCVA, while ELM and IS/OS integrity correlates well with BCVA. Outer retinal microstructure may represent anatomically better level of postoperative visual function than retinal thickness after pars plana vitrectomy for complications of proliferative diabetic retinopathy.

The role of the optical coherence tomography in identifying shape and size of idiopathic epiretinal membranes

AIM

Currently, the border of idiopathic epiretinal membranes (iERM) is outlined intraoperatively using vital dyes. Therefore, the authors set out to investigate the role of the preoperative retinal thickness map (RTM) of the optical coherence tomography (OCT) in identifying the shape and the size of the iERMs.

Methods

15 eyes of 15 patients with iERM who underwent vitrectomy with indocyanine green-assisted membrane peeling were included in this study. The authors analysed the intraoperative fundus images and preoperative Cirrus HD-OCT to detect the shape and the size of the iERM as well as the shape and the size of each thickness-indicating colour (white, red, orange and yellow) on the RTM, respectively. The correlation of areas and morphologic characteristics between both groups was explored.

Results

Analysis of iERM morphologic characteristics (shape) showed a similarity between the iERM contour and the corresponding RTM in 13 cases (86.6%). Furthermore, retinal folds were found in six iERMs and in their corresponding RTMs. Analysis of iERM size (area) revealed a positive correlation between the iERM area and each studied coloured area in RTM. The most significant correlation was between iERM and the red area (440–480 μm; r=0.87, p<0.0001).

Conclusion

The iERM-related retinal folds are clearly distinguishable on the HD-OCT. The red area in RTM representing the 440–480 μm retinal thickness can be a reliable predictor of the extent and the shape of the iERM.

The photoreceptor layer as a prognostic factor for visual acuity in the secondary epiretinal membrane after retinal detachment surgery: imaging analysis by spectral-domain optical coherence tomography

PURPOSE

To study the prognostic factors that influence best-corrected visual acuity (BCVA) outcome in patients with secondary epiretinal membrane (ERM) after retinal detachment surgery.

DESIGN

Retrospective case series.

METHODS

Forty-two patients with ERM were divided into macula-on and macula-off groups based on the macular status before retinal detachment surgery and were studied using the same spectral-domain optical coherence tomography device. Several variables, including the integrity of the external limiting membrane (ELM), the status of the photoreceptor inner segment/outer segment (IS/OS) junction line, and central foveal thickness were evaluated in 17 treated and 25 untreated patients. Linear regression analysis was used to determine the best combination of all variables affecting BCVA.

RESULTS

Final BCVA was significantly better in macula-on and macula-off eyes with intact ELMs and IS/OS junction lines (0.35 ± 0.18 logarithm of the minimal angle of resolution [logMAR] and 0.51 ± 0.17 logMAR, respectively) than in macula-off eyes with disrupted or absent ELMs and IS/OS junction lines (0.83 ± 0.17 logMAR and 1.04 ± 0.05 logMAR, respectively; P < .001, analysis of variance). Final BCVA also was better in the treated group than in the controls (0.55 ± 0.31 logMAR and 0.73 ± 0.26 logMAR, respectively; P = .05, t test). ELM and IS/OS junction line integrity were the main variables significantly affecting the final BCVA outcome (β = 0.42; P = .006, linear regression analysis). Disruption of the ELM and IS/OS junction line was observed in 21 of the 42 cases studied.

CONCLUSIONS

ERM secondary to retinal detachment surgery is accompanied by a high incidence (50%) of IS/OS junction line and ELM disruption. Among the variables studied, the condition of the IS/OS junction layer and the ELM are the main factors that predict final BCVA after ERM peeling.

Macular edema: miscellaneous

This article provides the reader with practical information to be applied to the various remaining causes of macular edema. Some macular edemas linked to ocular diseases like radiotherapy after ocular melanomas remained of poor functional prognosis due to the primary disease. On the contrary, macular edemas occurring after retinal detachment or after some systemic or local treatment use are often temporary. Macular edema associated with epiretinal membranes or vitreomacular traction is the main cause of poor functional recovery. However, the delay to observe a significant improvement of vision after surgery should be long, as usually observed in tractional myopic vitreoschisis. Finally, some circumstances of macular edemas such as hemangiomas or macroaneurysms should be treated, if symptomatic, with the treatments currently used in diabetic macular edema or exudative macular degeneration.

Disruption of the photoreceptor inner segment/outer segment layer on spectral domain-optical coherence tomography is a predictor of poor visual acuity in patients with epiretinal membranes

PURPOSE

The purpose of this study was to evaluate the predictive value of spectral domain-optical coherence tomography-determined integrity of the photoreceptor inner segment/outer segment (IS/OS) junction on visual acuity in patients with epiretinal membranes (ERMs).

METHODS

This is a retrospective consecutive case series of 54 eyes from 48 patients with primary ERMs who underwent spectral domain-optical coherence tomography scans. Regression analysis was used to calculate the relative contribution of several variables, including photoreceptor IS/OS disruption, grade of IS/OS disruption, macular thickness, and ERM grade on fundus imaging to visual acuity.

RESULTS

The strongest individual predictor of visual acuity among patients with ERM was central retinal thickness on spectral domain-optical coherence tomography (r(2) = 0.16, P = 0.0024), but the most efficient model was the combination of macular thickness and presence or absence of photoreceptor IS/OS disruption (r(2) = 0.24, P = 0.0008). Additional measured variables did not significantly contribute to visual acuity prediction. Inner segment/outer segment layer integrity was also an independent predictor of visual acuity, and patients with IS/OS disruption were 6.88 times as likely to have 20/50 or worse vision than patients with intact photoreceptor layers (odds ratio: 6.88, confidence interval: 1.56-30.43, P = 0.01).

CONCLUSION

Disruption of the photoreceptor IS/OS junction is a statistically significant predictor of poor visual acuity among patients with ERM and is most useful when combined with central retinal thickness measurement.

The association between percent disruption of the photoreceptor inner segment-outer segment junction and visual acuity in diabetic macular edema

PURPOSE

To evaluate the integrity of the photoreceptor inner segment/outer segment (IS/OS) junction using spectral-domain optical coherence tomography (SD OCT) in patients with diabetic macular edema and to correlate the relationship between the integrity of the IS/OS junction and visual acuity.

DESIGN

Retrospective, comparative, consecutive case series.

METHODS

Sixty-two eyes from 38 patients with diabetic macular edema underwent SD OCT imaging. For each patient, 2 experienced observers masked to visual acuity measured several SD OCT variables, including central macular thickness, retinal volume, global disruption scale of outer retina, percentage disruption of the outer retina, and history of previous treatments. Visual acuity recorded as number of Early Treatment Diabetic Retinopathy Study letters was used as the outcome variable in univariate and multivariate analysis testing the measured SD OCT variables as predictors.

RESULTS

A statistically significant correlation between percentage disruption of the IS/OS junction and visual acuity was found (P = .0312). Additionally, there was a strong trend suggesting a relationship between macular volume and visual acuity, although borderline significance was found (P = .07).

CONCLUSIONS

Disruption of the photoreceptor IS/OS junction is an important predictor of visual acuity among diabetic macular edema patients.

Optical coherence tomography for classification and clinical evaluation of macular edema in patients with uveitis

PURPOSE

To study use of optical coherence tomography (OCT) for macular edema in uveitis.

METHODS

In total, 44 patients with uveitis and macular edema underwent OCT. Data obtained were correlated with anatomic type, duration of uveitis, and visual acuity (VA).

RESULTS

Both cystoid macular edema (CME) and diffuse macular edema (DME) correlate negatively with VA, although statistically CME showed stronger correlation (p = .02). Also CME had higher mean foveal thickness than DME (p < .01). Negative correlation between foveal thickness and VA (p < .05) was observed. CME correlates with uveitis duration (p < .01).

CONCLUSIONS

CME and macular thickening correlate with VA reduction and uveitis duration.

Ultrastructural correlation of spectral-domain optical coherence tomographic findings in vitreomacular traction syndrome

PURPOSE

To examine the ultrastructural correlates of spectral-domain optical coherence tomography (SD-OCT) findings in patients with vitreomacular traction (VMT).

DESIGN

Observational case series.

METHODS

Retrospective analysis of six eyes of consecutive patients who underwent vitrectomy surgery for VMT was performed in this single-center, noncomparative study. One patient had a concurrent macular hole. Preoperative assessment included SD-OCT examination with 3-dimensional image reconstruction. During surgery the vitreous cone was dissected from the vitreous body using scissors, then removed from the surface of the retina with a combination of sharp dissection and peeling, and subsequently submitted for histologic and transmission electron microscopic processing.

RESULTS

SD-OCT showed prominent vitreal-foveal adhesion in all six eyes. Each eye had an epiretinal membrane (ERM) under the detached perifoveal posterior vitreous detachment. In all eyes this ERM appeared to course up the cone of attached vitreous and along the back surface of the posterior vitreous face. Ultrastructural analysis showed fibrocellular proliferations in the vitreous specimens in all six cases, which included retinal pigment epithelium (RPE) cells (five eyes), fibrocytes (four eyes), and macrophages (three eyes).

CONCLUSIONS

The adhesion between the vitreous and fovea in vitreomacular traction syndrome is accompanied by fibrocellular proliferation along the exposed surfaces of the inner retina and the posterior surface of the vitreous. This fibrocellular proliferation may augment the adhesion between the vitreous and fovea, and may account for the prominent OCT signal seen along the posterior surface of the vitreous in these cases.