Comparison and interchangeability of macular thickness measured with Cirrus OCT and Stratus OCT in myopic eyes

AIM: To investigate the difference of macular thickness measurements between stratus optical coherence tomography (OCT) and Cirrus OCT (Carl Zeiss Meditec, Dublin, CA, USA) in the same myopic patient and to develop a conversion equation to interchange macular thickness obtained with these two OCT devices. METHODS: Eighty-nine healthy Chinese adults with spherical equivalent (SE) ranging from -1.13 D to -9.63 D were recruited. The macular thickness was measured by Cirrus OCT and Stratus OCT. The correlation between macular thickness and axial length and the agreement between two OCT measurements were evaluated. A formula was generated to interchange macular thickness obtained with two OCT devices. RESULTS: Average macular thickness measured with Stratus OCT (r=-0.280, P=0.008) and Cirrus OCT (r=-0.224, P=0.034) were found to be negatively correlated with axial length. No statistically significant correlation was found between axial length and central subfield macular thickness (CMT) measured with Stratus OCT (r=0.191, P=0.073) and Cirrus OCT (r=0.169, P=0.113). The mean CMT measured with Cirrus OCT was 53.63±7.94 μm thicker than with Stratus OCT. The formula CMTCirrus OCT=78.328+0.874×CMTStratus OCT was generated to interchange macular thickness obtained with two OCT devices. CONCLUSION: Macular thickness measured with Cirrus OCT were thicker than with Stratus OCT in myopic eyes. A formula can be used to interchange macular thickness measured with two OCT devices in myopic eyes. Studies with different OCT devices and larger samples are warranted to enable the comparison of macular values measured with different OCT devices.     

Macular findings on optical coherence tomography in cat-scratch disease neuroretinitis

Purpose

To describe the macular findings on optical coherence tomography (OCT) in patients with cat-scratch disease (CSD) neuroretinitis.

Methods

Medical records of all patients diagnosed with CSD neuroretinitis at the Tel Aviv Medical Center between April 2006 and May 2010 were retrospectively reviewed. All patients underwent Stratus OCT macular examination.

Results

Eight eyes of seven patients with confirmed CSD neuroretinitis, (mean age 33±9.9 years, range 6–48 years) were included in the study. All patients presented clinically with optic nerve swelling and macular edema or macular exudates. OCT demonstrated flattening of the foveal contour, thickening of the neurosensory retina, and accumulation of subretinal fluid (SRF) in all studied eyes. Retinal exudates appeared as multiple hyper-reflective foci in the outer plexiform layer. The average central macular thickness was 460 μm (range 170–906 μm) and the average maximal retinal thickness was 613 μm (range 387–1103 μm), at presentation. The macula appeared normal on repeated exams during follow-up.

Conclusion

Similar OCT findings were demonstrated in patients with CSD neuroretinitis. SRF was found in all eyes, although was not visible on clinical examination or fluorescein angiography. OCT may be used as an adjunct imaging tool in the diagnosis and follow-up of patients with CSD neuroretinitis.     

Comparison of retinal thickness values and segmentation performance of different OCT devices in acute branch retinal vein occlusion

Purpose

To compare retinal thickness (RT) measurement and segmentation performance of time domain (TD, Stratus) and spectral domain (SD) optical coherence tomography (OCT) devices (Cirrus, Spectralis) for imaging macular oedema (ME) secondary to branch retinal vein occlusion (BRVO).

Methods

In this study, 20 eyes of 20 consecutive patients with acute BRVO were included. A total of 18 unaffected fellow eyes served as control group. RT measurement was analysed in the five inner fields of the early-treatment diabetic retinopathy grid, and proportional segmentation errors were evaluated.

Results

Central millimetre thickness (CMT) showed a mean difference of −64, −74, and −18 μm (P<0.001) in the control group and −31 μm (P=0.107), −92 μm (P<0.001), and −105 μm (P=0.016) in the BRVO group, between Stratus and Cirrus, between Stratus and Spectralis, and between Cirrus and Spectralis, respectively. Mean RT showed the highest variability between different devices in the area most intensively affected by BRVO-related ME. In eyes with BRVO, 14.6% of Spectralis, 20% of Stratus, and 36.6% of Cirrus scans demonstrated moderate and severe segmentation errors.

Conclusion

RT measurement in eyes with BRVO, by TD and SD OCT, is compromised by a significant rate of segmentation errors. Deviations are most pronounced in the areas most severely affected by ME.     

Relationship between perifoveal capillaries and pathomorphology in macular oedema associated with branch retinal vein occlusion

Purpose

To study the relationship between macular ischaemia on fluorescein angiography (FA) and pathomorphology at the foveal centre delineated by spectral-domain optical coherence tomography (OCT) in macular oedema (MO) associated with branch retinal vein occlusion (BRVO).

Methods

One hundred and five consecutive eyes of 105 patients with MO (centre point thickness (CPT) ≥300 μm) associated with BRVO in which FA using Heidelberg Retinal Angiography 2 and Spectralis OCT were performed on the same day were retrospectively reviewed. We evaluated the foveal pathomorphology using OCT images and the association with macular ischaemia.

Results

Within 1 year from symptom onset, 94 eyes were classified with perfused macula (34 eyes) or non-perfused macula (60 eyes). Eyes with perfused macula had better visual acuity and less CPT than those with non-perfused macula (P=0.024 and P<0.001, respectively). Fourteen eyes with perfused macula had serous retinal detachment (SRD) alone at the presumed foveal centre (SRD type); seven, a sponge-like swelling at that area (retinal swelling type); 11, foveal cystoid spaces alone (cystoid MO (CMO) type), and 2, with both SRD and foveal cystoid spaces (SRD+CMO type). However, 58 eyes with non-perfused macula had foveal cystoid spaces (42 of CMO type and 16 of SRD+CMO type), with a significant association between them (P<0.001). Among 11 eyes with symptoms exceeding 1 year, 6 eyes had perfused macula, and none had the SRD type.

Conclusion

Most eyes without foveal cystoid spaces have perfused macula in MO associated with BRVO.     

Observational study of subclinical diabetic macular edema

Purpose

To determine the rate of progression of eyes with subclinical diabetic macular edema (DME) to clinically apparent DME or DME necessitating treatment during a 2-year period.

Methods

In all, 43 eyes from 39 study participants with subclinical DME, defined as absence of foveal center edema as determined with slit lamp biomicroscopy but a center point thickness (CPT) between 225 and 299 μm on time domain (Stratus, Carl Zeiss Meditec) optical coherence tomography (OCT) scan, were enrolled from 891 eyes of 582 subjects screened. Eyes were evaluated annually for up to 2 years for the primary outcome, which was an increase in OCT CPT of at least 50 μm from baseline and a CPT of at least 300 μm, or treatment for DME (performed at the discretion of the investigator).

Results

The cumulative probability of meeting an increase in OCT CPT of at least 50 μm from baseline and a CPT of at least 300 μm, or treatment for DME was 27% (95% confidence interval (CI): 14%, 38%) by 1 year and 38% (95% CI: 23%, 50%) by 2 years.

Conclusions

Although subclinical DME may be uncommon, this study suggests that between approximately one-quarter and one-half of eyes with subclinical DME will progress to more definite thickening or be judged to need treatment for DME within 2 years after its identification.     

The relationship between the visual prognoses of branch retinal artery obstruction and foveal thickness on OCT

Purpose

To determine the correlation between the prognosis of branch retinal artery obstruction (BRAO) and the foveal thickness or outer nuclear layer (ONL) thickness on optical coherence tomography (OCT).

Methods

Twenty-one eyes (21 patients) in patients with resolved, non-complicated BRAO and a normal control of 10 eyes (10 volunteers) were used in this study. The average macular thickness, foveal thickness and ONL thickness at central fovea were measured in both the patients and the control group using spectral domain OCT. The thickness between the patient group and the control group were compared and correlation between the best corrected visual acuity (BCVA) and each thickness was determined.

Results

The average age of the patients was 52 ± 5.8 years. The average macular thickness, foveal thickness and ONL thickness at the central fovea of the patients were significantly (p < 0.001, p = 0.023, p = 0.021, respectively) thinner than that of the control group. Both the foveal thickness (r_s = 0.56, p = 0.008) and ONL thickness (r_s = 0.86, p < 0.001) were significantly correlated with BCVA. There was no significant correlation between the average macular thickness and BCVA.

Conclusions

The foveal thickness and ONL thickness at the fovea was positively correlated with the BCVA in patients with resolved BRAO.     

Influence of diabetes on macular thickness measured using optical coherence tomography: the Singapore Indian Eye Study

Purpose

To determine the influence of diabetes, diabetic retinopathy (DR), and other factors on macular thickness, measured using optical coherence tomography (OCT), in a population-based sample.

Methods

Data from the population-based Singapore Indian Eye Study were analyzed. We measured macular thickness using Stratus OCT Fast Macular Thickness scan protocol in 228 participants with diabetes mellitus (including 167 without DR, 44 with mild DR, 17 with moderate or severe DR) and 72 non-diabetic controls without macular oedema or other macular lesions. Analysis was done on right eyes.

Results

The mean age of participants was 60.1±10.1 years, with 53.8% men. Macular thickness measurements did not differ significantly between diabetic participants with no or mild DR and non-diabetic participants. Diabetic participants with moderate or severe DR had greater foveal and temporal outer macula thickness compared with those with no or mild DR (P=0.003). In a multivariate linear regression model, older age (P=0.009), male gender (P=0.005), and lower spherical equivalent (P=0.001) were other factors associated with greater foveal thickness in all participants after controlling for body mass index, glycosylated haemoglobin, total cholesterol, and mean systolic blood pressure.

Conclusion

This population-based study showed that diabetic participants with moderate or severe DR had thicker foveal measurements, even in the absence of diabetic macula oedema, than non-diabetic controls. Other factors that influenced macular thickness measurements were age, gender, and spherical equivalent. These data may aid the interpretation of OCT findings in persons with diabetes and DR.     

Surgical outcomes of macular buckling techniques for macular retinoschisis in highly myopic eyes

Purpose

To report the anatomic and visual results following macular buckling for patients with macular retinoschisis related to high myopia.

Methods

Thirty-nine highly myopic eyes (mean refractive error −16.7 D; range, −9 to −24 D) of 36 patients (mean age 59 years; range, 35–79 years) presenting with macular retinoschisis associated with a posterior staphyloma, who underwent combined vitrectomy and macular buckling were evaluated. Main outcome measures included best-corrected visual acuity (BCVA) and optical coherence tomography (OCT) findings. Three cases were excluded due to short follow-up (less than 3 months). The mean follow-up was 16 months.

Results

The mean BCVA increased from 0.76 to 0.43 LogMAR (p = 0.001). Visual acuity improved in 30 eyes (83.3%), remained stable in three eyes (8.3%) and decreased in three eyes (8.3%). OCT showed resolution of foveoschisis with foveal reattachment in all eyes. None of the evaluated patients developed a macular hole during follow-up.

Conclusion

Macular buckling associated with vitrectomy results in good anatomic and visual outcomes in patients with myopic foveoschisis.     

Intravitreal bevacizumab and ranibizumab injections for patients with polypoidal choroidal vasculopathy

Purpose

To compare the effectiveness of intravitreal injection of bevacizumab and ranibizumab in patients with treatment-naïve polypoidal choroidal vasculopathy (PCV).

Methods

A total of 66 and 60 eyes of 121 consecutive patients who received intravitreal bevacizumab (1.25 mg) or ranibizumab (0.5 mg) injection for treatment of PCV were retrospectively reviewed. After initial three loading injections by month, injection was performed as needed. Main outcome measures included best corrected visual acuity (BCVA), foveal center thickness (FCT) as assessed by spectral domain optical coherence tomography (SD-OCT), and change in polypoidal lesion on indocyanine green angiography (ICGA).

Results

At 12 months, average number of injections was 4.72±1.84 in the bevacizumab group and 5.52±1.54 in the ranibizumab group. Mean logarithm of the minimum angle of resolution of BCVA from baseline at 12 months after injection improved by 0.11 in the bevacizumab group (P=0.02) and by 0.14 in the ranibizumab group (P=0.01). Average FCT decreased from 368±62.48 to 298±40.77 μm in the bevacizumab group (P=0.01) and from 371±50.79 to 286±36.93 μm in the ranibizumab group (P=0.01). Polyp regression rate was 24.2% (16 eyes out of 66 eyes) in the bevacizumab group and 23.3% (14 eyes out of 60 eyes) in the ranibizumab group. There was no statistically significant difference in BCVA improvement achieved, FCT improvement achieved, and polyp regression rate between groups.

Conclusion

Intravitreal injections of bevacizumab and ranibizumab have similar effects in stabilization of visual acuity, macular edema, and regression of polypoidal complex with PCV eyes.     

Comparison of retinal nerve fiber layer and macular thickness measurements with Stratus OCT and OPKO/OTI OCT devices in healthy subjects

AIM: To compare retinal nerve fiber layer (RNFL) and macular thickness measurements obtained with the Stratus optical coherence tomography (OCT) and OPKO/OTI OCT devices. METHODS: Included in the study were 59 eyes of 30 participants. All measurements for each eye were done on the same day with both devices. Student’s paired t-tests were used to compare the central macular thickness and RNFL measurements of the Stratus OCT and OPKO/OTI OCT. Pearson correlation was used to assess the relationship between the devices. Coefficient of variation (COV) was calculated to assess intersession repeatability. RESULTS: Using both the Stratus OCT and OPKO/OTI OCT, respectively, the measured mean average RNFL thicknesses were 98.9±11.1 μm and 115.1±9.6 μm (P=0.001), and the measured mean central retinal thicknesses (CRT) were 196.2±18.8 μm and 204.5±21.1 μm (P<0.001). Measured by the two devices, the RNFL thickness values were correlated in all quadrants, as were the retinal thickness values except the inferior outer sector. COV for average RNFL and CRT thickness were 2.9% and 4.6% for Stratus OCT, and 2.1% and 4.2% for OPKO/OTI OCT, respectively. CONCLUSION: We found good reproducibility of RNFL and retina thickness measurements for both Stratus OCT and OPKO/OTI OCT devices. However, even though the two OCT systems provided statistically correlated results, the values for both RNFL and macular thickness were statistically different. RNFL and macular thickness measurements with the OPKO/OTI OCT were higher than that of the Stratus OCT; therefore, the two OCT systems cannot be used interchangeably for the measurements of RNFL and macular thickness.     

Spectral- and time-domain optical coherence tomography measurements of macular thickness in normal eyes and in eyes with diabetic macular edema

Purpose

To report macular thickness values in normal eyes and eyes with diabetic macular edema (DME) using time-domain (TD) and spectral-domain (SD) optical coherence tomography (OCT), and to derive a conversion equation.

Methods

The index study was a prospective investigation conducted on 80 eyes from 40 normal subjects and 130 eyes from 118 patients with DME seen in our clinic. Retinal thickness values from the central 1 mm of the macula and surrounding four ETDRS subfields were acquired using TD-OCT (Stratus OCT) and SD-OCT (SPECTRALIS HRA+OCT). Measurements of the central (C) subfield from both devices were used to derive a conversion equation. The equation was used to predict SD-OCT values using measurements from TD-OCT. Agreement between predicted and actual SD-OCT measurements was assessed.

Results

In normal eyes, the mean difference between TD-OCT and SD-OCT measurements of the C subfield was 76 μm (CI₉₅=74 and 77, respectively). The conversion equation, y=1.029x+72.49, was derived. In eyes with DME, using the equation, SPECTRALIS-predicted values were 5% higher than actual measurements, with 95% of predicted values falling within 9% of the actual measurements. Relocating SD-OCT grids to match the location on TD-OCT resulted in predicted values falling within 7% of actual measurements.

Conclusions

The percent difference between actual thickness measurements from SPECTRALIS and predicted thickness measurements, using the conversion equation, was within reported limits of repeatability of Stratus in eyes with DME. Our equation may help correlate OCT values from both devices in standard care and clinical trials for DME.     

Foveal Thickness between Stratus and Spectralis Optical Coherence Tomography in Retinal Diseases

Purpose

To compare the foveal thickness (FT) parameters measured by Stratus optical coherence tomography (OCT) and Spectralis OCT in various retinal diseases and to construct conversion formulas between the two types of OCT devices.

Methods

We examined 366 consecutive patients (475 eyes) with retinal diseases and 13 normal controls (13 eyes). The patients were categorized into eight retinal disease groups. The mean amount and distribution of foveal thickness differences (FTD) measured by Stratus and Spectralis OCT were determined, and conversion formulas were constructed for Stratus OCT FT from Spectralis OCT FT for each retinal disease group.

Results

Among retinal diseases, the mean FTD was significantly larger in exudative age-related macular degeneration (AMD) patients (mean ± SD, 94.0 ± 55.0 µm) compared to normal subjects (66.2 ± 11.7 µm; p < 0.0001). The proportion of eyes with a mean FTD outside 1.96 standard deviations of normal subject FTD was greatest in the exudative AMD (50.0%) group and smallest in the macular hole (18.2%) group. The predicted FTs obtained through the conversion formulas showed lower variance than the actual FTD values, especially in the exudative AMD group. The prediction line for exudative AMD deviated most from that of normal subjects.

Conclusions

FTD shows diverse values and variances among various retinal diseases, especially in exudative AMD, which indicates that Stratus OCT FT cannot be predicted from Spectralis OCT FT by FTD value alone. We constructed statistically significant conversion formulas, which provided more reliable methods to predict Stratus OCT-measured FT from Spectralis OCT measurements for different retinal disease groups.     

Effect of a single intravitreal bevacizumab injection on different optical coherence tomographic patterns of diabetic macular oedema

Purpose

The aim of this study is to compare the therapeutic effect of a single intravitreal bevacizumab (IVB) injection in eyes with diabetic macular oedema (DMO) of different patterns determined by optical coherence tomography (OCT).

Methods

Medical records of patients who had a single IVB injection for DMO were analysed retrospectively. Eyes with a clinically significant DMO and a central foveal thickness (CFT) of 250 μm or more determined by OCT were included in the analysis. Best-corrected visual acuity (BCVA), CFT and total macular volume values before and after the injection were recorded. Eyes were divided into sponge-like diffuse retinal thickening (DRT), cystoid macular oedema (CMO) and serous retinal detachment (SRD) groups according to the morphology on OCT.

Results

A total of 92 eyes (42 with DRT, 31 with CMO and 19 with SRD) were included in the study. There was no statistically significant variation between three groups regarding the change in BCVA (P=0.695). CMO and SRD groups had greater reductions in their mean CFT, and the amount of reduction showed statistically significant variation between three groups (P=0.048). However, no statistically significant difference was found between groups in terms of percentage of change in CFT (P=0.278).

Conclusion

CMO and SRD subtypes are associated with a greater reduction in the CFT than the DRT subtype. Although the change in BCVA was not significantly different between groups, the DRT group showed markedly better visual improvement in proportion to the decrease in CFT.     

Two-wavelength fundus autofluorescence and macular pigment optical density imaging in diabetic macular oedema

Purpose

To evaluate the application of 488 and 514 nm fundus autofluorescence (FAF) and macular pigment optical density (MPOD) imaging in diabetic macular oedema (DMO) and to demonstrate the typical imaging features.

Patients and Methods

A hundred and twenty-five eyes of 71 consecutive patients with diabetic retinopathy who underwent examination at a specialist university clinic employing a modified Heidelberg Retina Angiograph, using two different light sources of 488 and 514 nm wavelength, were retrospectively reviewed. MPOD images were calculated using modified Heidelberg Eye Explorer software. All images were evaluated by two independent masked graders. Features from FAF and MPOD images were correlated with optical coherence tomography (OCT) imaging findings and inter-grader variability, sensitivity and specificity were calculated using OCT as reference.

Results

Sixty-seven eyes had DMO on OCT. The inter-grader variability was 0.84 for 488 nm FAF, 0.63 for 514 nm FAF and 0.79 for MPOD imaging. Sensitivity and specificity for detection of DMO were 80.6 and 89.7% for 488 nm FAF; 55.2 and 94.8% for 514 nm FAF; and 80.6 and 91.4% for MPOD imaging. In 488 nm FAF and MPOD imaging, DMO was better visualised in comparison with 514 nm FAF imaging, P<0.01. MPOD revealed displacement of macular pigment by intraretinal cysts.

Conclusion

MPOD imaging, and particularly its combination with 488 nm and 514 nm FAF, provides a valuable addition to OCT in the evaluation of DMO and is clinically useful in rapid en-face assessment of the central macula.     

Pilot study to evaLuate the role of high-dose rAnibizumab 2.0 mg in the management of neovascular age-related macular degeneration in patients with perSistent/recurrenT macular fluid <30 days following treatment with intravitreal anti-VEGF therapy (the LAST Study)

Purpose

To determine the efficacy of intravitreal ranibizumab 2.0 mg in patients with recalcitrant neovascular age-related macular degeneration (AMD).

Methods

This single-masked, randomized, prospective, pilot study enrolled patients with subfoveal neovascular AMD. All study eyes had persistent subretinal (SRF) or intraretinal fluid (IRF) on spectral-domain optical coherence tomography (SD-OCT) <30 days following at least 6 monthly intravitreal injections of ranibizumab or bevacizumab. Patients were randomized 2 : 1 to receive either ranibizumab 2.0 or 0.5 mg. Following three-loading treatments 4-weeks apart, both groups were treated using a ‘treat and extend'' regimen guided by eye-tracked SD-OCT through month 12. The primary end point was the mean change in best-corrected visual acuity (BCVA) at month 6.

Results

Nine eyes of 9 patients (mean age±SD, 82.0±5.8 years) were enrolled. Seven eyes received ranibizumab 2.0 mg and two eyes received 0.5 mg. Owing to the small number of patients enrolled, no statistical comparison could be made between the two dosages. At month 6, the mean improvement in BCVA was +6.1±3.7 (W=0, P<0.001) ETDRS letters and +2.0 ETDRS letters in the 2.0 and 0.5 mg groups, respectively. In the 2.0 mg group, there was a statistically significant decline in central foveal thickness, SRF and maximum pigment epithelial detachment height at 6 months compared with baseline. No adverse events were reported in either group.

Conclusion

Ranibizumab 2.0 mg has the potential to maintain or improve BCVA in some patients with persistent or recurrent SRF or IRF secondary to neovascular AMD despite prior monthly intravitreal anti-vascular endothelial growth factor therapy with the standard dose.     

Determination of macular hole size in relation to individual variabilities of fovea morphology

Purpose

To determine the preoperative anatomic factors in macular holes and their correlation to hole closure.

Methods

Forty-six eyes with consecutive unilateral macular hole who had undergone surgery and followed up for at least 6 months were enrolled. Optical coherence tomography images and best-corrected visual acuity (BCVA) within 2 weeks prior to operation and 6 months after surgery were analyzed. The maximal hole dimension, foveal degeneration factors (inner nuclear layer cysts, outer segment (OS) shortening) and the widest foveolar floor size of the fellow eyes were measured. For overcoming preoperative individual variability of foveal morphology, an ‘adjusted'' hole size parameter (the ratio between the hole size and the fellow eye foveolar floor size) was used based on the fact that both eyes were morphologically symmetrical.

Results

Mean preoperative BCVA (logMAR) was 1.03±0.43 and the mean postoperative BCVA was 0.50±0.38 at 6 months. Preoperative BCVA is significantly associated with postoperative BCVA (P=0.0002). The average hole diameter was 448.9±196.8 μm and the average fellow eye foveolar floor size was 461.3±128.4 μm. There was a correlation between hole diameter and the size of the fellow eye foveolar floor (Pearson''s coefficient=0.608, P<0.0001). The adjusted hole size parameter was 0.979±0.358 (0.761–2.336), which was a strong predictor for both anatomic (P=0.0281) and visual (P=0.0016) outcome.

Conclusion

When determining the extent of preoperative hole size, we have to take into consideration the foveal morphologic variations among individuals. Hole size may be related to the original foveal shape, especially in relation to the centrifugal retraction of the foveal tissues.     

Comparison of retinal nerve fiber layer measured by time domain and spectral domain optical coherence tomography in optic neuritis

Purpose

To study the relationship between retinal nerve fiber layer (RNFL) thickness measurements from time domain (Stratus) and spectral domain (Cirrus HD) optical coherence tomography (OCT) in subjects with optic neuritis.

Methods

A total of 18 patients who had suffered monocular acute optic neuritis were imaged by a single trained operator using the Stratus-OCT (fast RNFL scan mode) and Cirrus HD-OCT (optic disc cube mode) on the same day. The relationship between RNFL thickness measurements of the two OCTs (overall and by quadrants) were evaluated using intraclass correlation coefficient (ICC) and Bland–Altman plots. Comparisons between eyes having optic neuritis (ON-group) and fellow eyes (fellow-group) were assessed by a generalized estimating equation (GEE) regression model.

Results

For Stratus-OCT, the median average RNFL was 86.3 and 102 μ in the ON-group and in the fellow-group, respectively. For Cirrus-OCT, the corresponding measurements were 81 and 93 μ. Average RNFL thickness as determined by the two OCT devices was well correlated in the ON-group (ρ=0.906, P<0.001) and in the fellow-group (ρ=0.702, P=0.001). The median signal strength was significantly higher with Cirrus-OCT. Bland–Altman plots showed that Stratus RNFL measurements were larger than Cirrus-OCT, but smaller when average RNFL thickness was very thin (≤56 μ).

Conclusions

Although the Cirrus-OCT and Stratus-OCT RNFL thickness measurements are well correlated in patients with optic neuritis, RNFL measurements cannot be directly compared. Clinicians should be aware that measurements are generally higher with Stratus- than with Cirrus-OCT.     

Qualitative and quantitative OCT response of diffuse diabetic macular oedema to macular laser photocoagulation

Purpose

To assess the quantitative and morphological changes of the macula in response to macular grid laser for diabetic macular oedema (DMO) using optical coherence tomography (OCT).

Patients and Methods

Cirrus OCT macular cube scans of 30 eyes of 25 patients were retrospectively analysed before and 4 months after macular grid laser for diffuse DMO. The oedema was quantified and response evaluated in the nine early-treatment diabetic retinopathy study (ETDRS) zones of the macula. Post-laser OCT changes were compared with the baseline features, including morphology patterns, changes in both logarithmic transformed (logOCT) and standardised average macular thickness (AMT), total macular volume, number of parafoveal quadrants involved, and the presence of intact 3rd hyper-reflective band (HRB).

Results

The rate of change of retinal thickness in response to laser was maximum in the central (8.17%) and perifoveal inferior quadrants (0.04%). Diffuse retinal thickening on OCT responded best to treatment. The AMT of 300–350 μm had the worst response (+0.94%). Eyes with less than four quadrants of oedema showed good response. Disrupted HRB was associated with poor visual gain (−0.33 ETDRS letters).

Conclusion

The topographic location of oedema on the retinal map and the morphological patterns of the oedema on OCT are useful predictors of treatment response in diffuse DMO.     

External limiting membrane and visual outcome in macular hole repair: spectral domain OCT analysis

Purpose

To investigate the relationship between postoperative visual acuity and integrity of the external limiting membrane (ELM) and inner segment–outer segment (IS–OS) junction layers, using spectral domain optical coherence tomography (SD-OCT), in eyes with macular holes (MHs) following surgical repair.

Methods

Medical charts of MH-operated cases were retrospectively identified and reviewed. The primary outcome measures were best-corrected visual acuity (BCVA) and the status of the ELM and IS–OS lines, using SD-OCT, at 6 weeks and 6 months postoperatively.

Results

Sixty-two eyes of 62 patients were included. At 6 weeks following surgery, out of 56 (90.3%) eyes with successful MH closure: 0 eyes showed the combination of disrupted ELM and continuous IS–OS layers; 7 eyes (12.5%) demonstrated continuity of both ELM and IS–OS (ELM^c/IS–OS^c group); 29 eyes (51.8%) had continuous ELM with discontinuous IS–OS layers (ELM^c/IS–OS^d group); and 20 eyes (35.7%) had discontinuities in both the layers (ELM^d/IS–OS^d group). The ELM^d/IS–OS^d group had the lowest visual gain at 6 months (P=0.03). At 6 months, a restoration of the integrity of IS–OS layer was observed in 51.7% eyes in the ELM^c/IS–OS^d group and in 5% in the ELM^d/IS–OS^d group (P=0.001).

Conclusions

When both ELM and IS–OS layers showed disruptions 6 weeks postoperatively, a significantly worse BCVA was measured at 6 months, compared with the eyes with only IS–OS disruptions, detected 6 weeks following surgery. The integrity of the ELM layer appears to be a critical factor for the restoration of the photoreceptor layer and for predicting a successful visual outcome following MH repair.     

Association of outer retinal layer morphology with visual acuity in patients with retinal vein occlusion: SCORE Study Report 13

Purpose

To assess associations between visual acuity (VA) and the status of the photoreceptor inner segment–outer segment (IS–OS) junction in a subset of patients in the Standard Care vs COrticosteroid for REtinal Vein Occlusion (SCORE) Study.

Methodology

High-resolution time domain optical coherence tomography (OCT) scans of study eyes from a single site participating in the SCORE Study were evaluated. Integrity of the IS–OS junction in the central subfield was evaluated using a three-step scale: absent, abnormal or normal. Associations of the IS–OS status with ETDRS VA letter score and center point thickness (CPT) were investigated.

Results

Baseline OCTs of 42 eyes were evaluated. The IS–OS junction was absent in 30 (71%) and abnormal in 12 (29%). At month 12, the IS–OS junction was absent in 18 (43%), abnormal in 12 (28%), and normal in 12 (28%) eyes. At baseline, IS–OS status was significantly associated with CPT, but not with VA. At month 12, IS–OS status was significantly associated with CPT and VA, that is, absent or abnormal IS–OS was associated with increased CPT and worse VA. Change in IS–OS status was not associated with change in CPT (P=0.8). Worsening of IS–OS status was associated with loss of VA and improvement in IS–OS status to normal was associated with gain in VA (P=0.03).

Conclusion

In this data set with long-term follow-up of OCTs as part of the SCORE Study, there is a correlation between change in IS–OS status and VA. This supports further evaluation of outer retinal morphology in larger data sets.