Optical coherence tomography in photodynamic therapy for subfoveal choroidal neovascularisation secondary to age related macular degeneration: a cross sectional study

Trends in application of fundus fluorescein angiography in fundus diseases during a recent ten-year period

PURPOSE

To analyze the trends in the application of fundus fluorescein angiography (FFA) in fundus diseases over ten years.

METHOD

It was a retrospective study. Patients who underwent FFA examinations between Jan 2012 and Dec 2021 in Eye Hospital of Wenzhou Medical University were included, excluding infants. Data included the fundus disease and examination time of FFA.

RESULTS

A total of 37,038 cases underwent FFA examinations in our hospital in the past decade, and the number of each year was 3,628, 2,232, 2,230, 2,351, 3,546, 3,924, 5,325, 4,202, 4,432 and 5,168 from 2012 to 2021, respectively. The top three diseases were central serous chorioretinopathy (CSC), diabetic retinopathy (DR) and retinal vein occlusion (RVO) over the years from 2012 to 2021. The fourth to eighth ranked diseases were uveitis, age-related macular degeneration (AMD), choroidal neovascularization (CNV), optic neuropathy (ON) and polypoid choroidal vasculopathy (PCV) 9 years from 2012 to 2020; while retinal artery occlusion (RAO) ranked eighth and PCV fell out of the first eight in 2021. Tumor, Eale's disease, macular hemorrhage (MH), epiretinal retinal membrane (ERM) and Coat's disease had consistent proportions over the years. There was a significant statistical difference in the proportion of disease components over the years from 2012 to 2021(p = 0.000).

CONCLUSION

Despite changes in annual distribution, CSC, DR, and RVO consistently ranked as the top three diseases requiring FFA examination. Changes might be related to the development of non-invasive fundus examination instruments and technologies. Indicated that FFA still hold its irreplaceable nature in diagnosing and understanding fundus diseases.

Morphological changes in retinochoroidal microvasculature after caffeinated versus decaffeinated coffee consumption

BACKGROUND

To investigate changes in retinochoroidal microvascular morphology after caffeinated versus decaffeinated coffee consumption in age- and gender-matched healthy individuals using optical coherence tomography (OCT) and OCT angiography (OCTA).

METHODS

In this prospective, randomized clinical study, a staff member in charge of record keeping randomly assigned 48 healthy volunteers to two groups: caffeinated coffee consumers (24 eyes) and decaffeinated coffee consumers (24 eyes). Participants' ages and genders were recorded before consumption, and a comprehensive ophthalmologic exam was performed, followed by OCT and OCTA analyses before, 30 min, one, six, and 24 h after blindly consuming either of the coffees.

RESULTS

Caffeinated and decaffeinated coffee consumers had mean ages of 23.45 ± 0.92 and 22.73 ± 1.13, respectively (p = 0.407). The following parameters changed significantly in caffeinated coffee consumers 30 min and 1 h post-consumption (pre-consumption versus 30 min versus one hour post-consumption; p < 0.05): a) parafoveal superficial capillary plexus vessel density (%): 54.45 versus 51.8 versus 51.92, b) parafoveal deep capillary plexus vessel density (%): 55.16 versus 52.45 versus 52.83, c) outer retinal flow area (%): 8.87 ± 1.91 versus 8.03 ± 1.88 versus 8.11 ± 1.93, d) choriocapillaris flow area (mm²): 20.95 ± 0.98 versus 19.82 ± 1.20 a versus 19.62 ± 0.95, and e) sub-foveal choroidal thickness (µm): 295.06 ± 5.45 versus 277.08 ± 5.33 versus 260.71 ± 58.61. No significant differences in any OCT and OCTA parameters were found between consecutive measurements in decaffeinated coffee consumers (p > 0.05).

CONCLUSIONS

Caffeinated coffee appears to transiently reduce parafoveal vessel density, capillary flow area, and sub-foveal choroidal thickness. Lack of these microvascular morphological changes in decaffeinated coffee suggests a potential caffeine-induced vasoconstrictive effect.

Short-Term Outcomes After COVID-19-Related Treatment Interruption Among Patients with Neovascular Age-Related Macular Degeneration Receiving Intravitreal Bevacizumab

Purpose

To assess outcomes and recovery strategy of patients undergoing intravitreal injections for exudative age-related macular degeneration who experienced COVID-19 related interruption in treatment during complete lockdown.

Methods

This was a retrospective, observational case study. We used a mixed effect model with random intercepts to evaluate best corrected visual acuity (BCVA) accounting for measured central macular thickness (CMT) and individual variability of each eye. Furthermore, we analysed measures of the pigmented epithelium detachment as well as presence of subretinal fluid and intraretinal cysts.

Results

We included 39 patients and we found a significant reduction in the BCVA between the pre- and post-lockdown controlling for CMT. There was no significant difference in pigmented epithelium detachment and in presence of subretinal fluid and intraretinal cysts.

Conclusion

We detected a significant loss in visual function. The magnitude of the average loss was, however, limited suggesting good efficacy of the recovery strategy.

In vivo optical coherence tomography-guided photodynamic therapy for skin pre-cancer and cancer

BACKGROUND

The primary aim of this prospective study is to demonstrate the technical feasibility of OCT to map real tumor margins and to monitor skin changes that occurred post- PDT. Moreover, to optimize PDT efficacy based on the relationship between measured OCT features and treatment outcome.

MATERIAL AND METHODS

A series of 12 patients with overall 18 facial skin lesions were investigated by OCT before surface illumination by PDT to determine tumor free margins. Monitoring of the healing process was undertaken at 3, 6 and 12 months post-PDT. Parameters measured by the in vivo OCT during healing phase were the organization of skin layer and the degree skin fibroses for the active center and peripheral transit zone of the treated lesion. Clinical and aesthetics assessment was carried out at 12-month post-PDT.

RESULTS

Distinct microstructural differences between normal skin, pre-cancer, cancer, and the transition zone between the two tissues were observed on OCT images. In the subsequent healing phase, OCT demonstrate marked delineation and organization of skin layer at late stage of healing. Early features showing bizarre non-homogenous disorganized layering (scab) but afterwards, OCT was able to differentiate between different histological layers. One lesion demonstrated clinical healing by fibrosis (scar) without sign of recurrence. Another lesion demonstrated skin erythema. Only one lesion did not response to treatment despite margins clearance. The CR rate was 95% at the end of the study. The cosmetic effect was "excellent" in 89% of the patients.

CONCLUSIONS

This feasibility study lays the groundwork for using OCT as a real-time, noninvasive monitoring device for PDT in patients with skin cancer.

Type 3 neovascularisation: long-term analysis of visual acuity and optical coherence tomography anatomical outcomes

BACKGROUND

To investigate the long-term visual and optical coherence tomography (OCT) anatomical outcomes of type 3 neovascularisation (NV) and to identify any baseline predictors of poor outcomes.

METHODS

In this retrospective study, patients diagnosed with treatment naïve type 3 NV were identified and categorised into two groups: good or poor vision based on final vision at 1 year. Baseline demographic features and visual acuity (VA) and baseline and 1-year spectral domain OCT (SD-OCT) anatomical findings were studied and correlated with good versus poor visual outcomes.

RESULTS

Ten of 25 eyes were classified as having a poor visual outcome (20/50 or worse) at 1 year. Increased age (P=0.049), male gender (p=0.041) and worse baseline VA (ρs=0.61, p=0.001) were associated with poor vision at 1 year. Greater foveal atrophy was noted at 1 year in the poor visual outcome group (p=0.030). Subretinal hyper-reflective material and choroidal thinning were additional features noted more commonly in this group.

CONCLUSION

Increased age, male gender and lower baseline vision may be important baseline predictors of poor visual outcomes in eyes with type 3 NV. The development of central outer retinal atrophy and fibrosis, as identified with SD-OCT, may limit long-term vision in eyes with type 3 NV.

Deep-learning based, automated segmentation of macular edema in optical coherence tomography

Evaluation of clinical images is essential for diagnosis in many specialties. Therefore the development of computer vision algorithms to help analyze biomedical images will be important. In ophthalmology, optical coherence tomography (OCT) is critical for managing retinal conditions. We developed a convolutional neural network (CNN) that detects intraretinal fluid (IRF) on OCT in a manner indistinguishable from clinicians. Using 1,289 OCT images, the CNN segmented images with a 0.911 cross-validated Dice coefficient, compared with segmentations by experts. Additionally, the agreement between experts and between experts and CNN were similar. Our results reveal that CNN can be trained to perform automated segmentations of clinically relevant image features.

Standardization of choroidal thickness measurements using enhanced depth imaging optical coherence tomography

AIM

To describe and evaluate a standardized protocol for measuring the choroidal thickness (ChT) using enhanced depth imaging optical coherence tomography (EDI OCT).

METHODS

Single 9 mm EDI OCT line scans across the fovea were used for this study. The protocol used in this study classified the EDI OCT images into four groups based on the appearance of the choroidal-scleral interface and suprachoroidal space. Two evaluation iterations of experiments were performed: first, the protocol was validated in a pilot study of 12 healthy eyes. Afterwards, the applicability of the protocol was tested in 82 eyes of patients with diabetes. Inter-observer and intra-observer agreements on image classifications were performed using Cohen's kappa coefficient (κ). Intraclass correlation coefficient (ICC) and Bland-Altman's methodology were used for the measurement of the ChT.

RESULTS

There was a moderate (κ=0.42) and perfect (κ=1) inter- and intra-observer agreements on image classifications from healthy eyes images and substantial (κ=0.66) and almost perfect (κ=0.86) agreements from diabetic eyes images. The proposed protocol showed excellent inter- and intra-observer agreements for the ChT measurements on both, healthy eyes and diabetic eyes (ICC>0.90 in all image categories). The Bland-Altman plot showed a relatively large ChT measurement agreement in the scans that contained less visible choroidal outer boundary.

CONCLUSIONS

A protocol to standardize ChT measurements in EDI OCT images has been developed; the results obtained using this protocol show that the technique is accurate and reliable for routine clinical practice and research.

The role of epiretinal membrane on treatment of neovascular age-related macular degeneration with intravitreal bevacizumab

Purpose. To determine the effect of epiretinal membranes (ERM) on the treatment response and the number of intravitreal bevacizumab injections (IVB) in patients with neovascular age-related macular degeneration (nAMD). Methods. A retrospective chart review was performed on 63 eyes of 63 patients. The patients were divided into AMD group (n = 35) and AMD/ERM group (n = 28). Best corrected visual acuity (BCVA) and central retinal thickness (CRT), as well as the number of injections, were evaluated. Results. There was a significant improvement in BCVA at 3 months for the AMD and AMD/ERM groups (P = 0.02, P = 0.03, resp.). At 6, 12, and 18 months, BCVA did not change significantly in either of the groups compared to baseline (P > 0.05 for all). At 3, 6, 12, and 24 months, the AMD group had an improvement in BCVA (logMAR) of 0.09, 0.06, 0.06, and 0.03 versus 0.08, 0.07, 0.05, and 0.03 for the AMD/ERM group (P = 0.29, P = 0.88, P = 0.74, P = 0.85, resp.). A significant decrease in CRT occurred in both groups for all time points (P < 0.001 for all). The change in CRT was not statistically different between the two groups at all time points (P > 0.05 for all). The mean number of injections over 24 months was 8.8 in the AMD group and 9.2 in the AMD/ERM group (P = 0.76). Conclusion. During 24 months, visual and anatomical outcomes of IVB in nAMD patients were comparable with those in nAMD patients with ERM with similar injection numbers.

Computerized assessment of intraretinal and subretinal fluid regions in spectral-domain optical coherence tomography images of the retina

PURPOSE

To evaluate a new computerized segmentation technique for the quantification of intraretinal and subretinal fluid in spectral-domain optical coherence tomography (SD OCT) images of the retina.

DESIGN

Prospective, cross-sectional study.

METHODS

Thirty-seven B-scan images of 37 patients with exudative age-related macular degeneration were chosen randomly from SD OCT volume scans (1 per volume scan). All hyporeflective areas in the image first were segmented automatically as candidate regions by the program. Researchers who were masked to the candidate region information selected each fluid region from the original image using a single mouse click. The program then delineated the boundary of each region selected and calculated quantitative parameters, including total area of fluid regions if multiple regions were selected. The performance of our technique was validated by comparing the results with the measurements obtained from boundaries manually delineated by 2 masked observers. Time efficiency, agreement with manual delineation, and intraobserver and interobserver agreement of using the program were evaluated.

RESULTS

The proposed technique reduced the average processing time per image approximately 6-fold (15 seconds for computerized segmentation vs 90 seconds for manual delineation). There was good agreement between computerized segmentation and manual delineation measured by intraclass correlation coefficient (range, 0.897 to 0.979) and the Dice coefficient (range, 0.721 to 0.785). The proposed technique has excellent intraobserver and interobserver agreement (intraclass correlation coefficient range, 0.998 to 0.999; Dice coefficient range. 0.959 to 0.981).

CONCLUSIONS

This computerized segmentation method allows for accurate and fast quantification of fluid in retinal SD OCT images and could assist in monitoring disease progression and evaluating therapeutic intervention.

Vitreoretinal interface in central serous choroidopathy: a retrospective case-control study

PURPOSE

To investigate the frequency and patterns of vitreoretinal adherence in central serous choroidopathy (CSC) using spectral domain optical coherence tomography (SD-OCT) imaging and compare them with normal subject.

METHODS

A descriptive observational analytical retrospective case-control study. The study patients were split into non-chronic and chronic CSC groups and compared with an age- and gender-matched control group composed of healthy individuals without CSC. Five patterns of vitreoretinal adherence were defined: lacunae, partial posterior vitreous detachment (partial-PVD), epiretinal membrane (ERM), focal vitreomacular adherence (VMA) and no recognizable pattern. Statistical analysis was performed.

RESULTS

One hundred and four eyes of 52 patients were included in this study. Forty-eight eyes of 24 patients had chronic CSC and 56 eyes of 28 patients had non-chronic CSC. The control group for chronic CSC included 96 normal eyes of 48 subjects, and the control group for non-chronic CSC included one hundred and twelve normal eyes of 56 subjects. We found a recognizable pattern of the vitreoretinal interface (lacuna, partial-PPV, VMA or ERM) more often in non-chronic CSC (p = 0.0001, OR = 6.51 and CI = 2.71-15.62) and in chronic CSC patients (p = 0.001, OR = 4.05, CI: 1.77-9.57) than in normal subjects.

CONCLUSION

The proportion of patterns of vitreoretinal adherence and interface found in CSC changes with age and manifests differently compared with normal eyes. The results indicate early changes in CSC patients younger than 40 years of old bilaterally.

Appearance of age-related macular degeneration in vitrectomized and nonvitrectomized eyes: an intraindividual case study

PURPOSE

This study analyses the consequences of vitreoretinal traction on the macula and in particular the impact of a vitrectomy on the development of the age-related macular degeneration (ARMD).

METHODS

In this retrospective case study, 42 eyes of 21 subjects were examined. The vitreous of one eye must have been removed by vitrectomy at least 8 years ago. At that point in time, the patients had to be at least 50 years old, with a healthy vitreous body of the other eye and a healthy macula in both eyes. Both eyes were examined using an optical coherence tomography (OCT) scan, B-scan ultrasound, a binocular slit-lamp funduscopy and a fluorescence angiography (FAG) to evaluate the potential development stage of an ARMD and the vitreous status.

RESULTS

In the follow-up examination, the patients had an average age of 73.6 years. In 0 of 21 vitrectomized eyes (0%), there were signs for an early ARMD. In 5 of 21 nonvitrectomized eyes (23.8%), we found ARMD-like changes in the angiography and slit-lamp examinations. Of these 21 eyes, five eyes presented persistent attachment of the posterior vitreous cortex to the macula, while 16 eyes showed complete posterior vitreous detachment. All five eyes (100%) with premonitory signs of an ARMD showed persistent attachment of the posterior vitreous to the macula.

CONCLUSION

We demonstrated a positive relationship between a persistent attachment of the posterior vitreous cortex to the macula and early signs of ARMD. Although the precise mechanism of this relationship remains unclear, the role of chronic low-grade inflammation, chronic oxidative and mechanical stress and an increase in VEGF is discussed. Persistent vitreous attachment is likely to be another risk factor for ARMD.

Evaluation of segmentation procedures using spectral domain optical coherence tomography in exudative age-related macular degeneration

PURPOSE

The purpose of this study was to evaluate standardized automated segmentation procedures of spectral domain optical coherence tomography (SD-OCT) in imaging of age-related macular degeneration.

METHODS

Twenty-nine eyes of 29 patients with neovascular age-related macular degeneration were included. Three groups were assigned, according to the predominant localization of extravasated fluid in the intra-, subretinal, and subretinal pigment epithelium (RPE) compartment. Automated segmentation procedures were evaluated in B scans of 512 × 128 × 1024 and 200 × 200 × 1024 scan patterns using SD-OCT (Cirrus). Alignment errors at the internal limiting membrane, actual RPE, and extrapolation of the physiologic RPE (RPE fit) were graded using a standardized classification system.

RESULTS

The rate of severe alignment failures was 56% and 41% for the 512 × 128 and the 200 × 200 raster pattern, respectively. Internal limiting membrane and actual RPE boundaries were most correctly delineated in the 200 × 200 raster pattern. Retinal pigment epithelium fit alignment was generally poor in 50% of scans. Retinal thickness values defined by internal limiting membrane and actual RPE segmentation were 90% accurate and not compromised by RPE fit misalignment. Subretinal fluid was demarcated most reliably. Alignment errors may occur together with a large spectrum of morphologic alterations.

CONCLUSION

Automated algorithms of SD-OCT demonstrate a substantial rate of alignment failures in the assessment of exudative age-related macular degeneration pathologies, which are usually associated with misinterpretation of boundaries at the (sub) RPE level.

Early visual impacts of optical coherence tomographic parameters in patients with age-related macular degeneration following the first versus repeated ranibizumab injection

BACKGROUND

The aim of this study is to evaluate the early visual impacts of various optical coherence tomographic (OCT) parameters after the first versus repeated intravitreal ranibizumab injection in patients with exudative age-related macular degeneration (AMD).

METHODS

A retrospective comparative case series study was conducted on 20 eyes of 18 consecutive patients who received intravitreal ranibizumab injection for exudative AMD either for the first time (group 1; n = 8) with no prior anti-vascular endothelial growth factor (anti-VEGF) injection in the same or fellow eye, or for repeated times during the course of monthly injected ranibizumab (group 2; n = 12 eyes). The following baseline and 1 month post-injection data was collected for both groups and compared: best-corrected visual acuity (BCVA), qualitative and quantitative OCT parameters including: foveal thickness, foveal volume (central 1-mm circle), retinal volume at 3- and 5-mm central circles, retinal pigment epithelium (RPE) elevation, type of fluid collections, and type of AMD lesion. The size of the fluid and fibrovascular lesion (FVL) areas were measured using manual delineation and automatic calculation of the device. We made correlations between the post-injection visual acuity (VA) and each of post-injection OCT parameters in both groups and these were the main outcome measures.

RESULTS

In group 1, there was a strong correlation between post-injection logarithm of minimum angle of resolution (logMAR) BCVA and each of the following: FVL size, foveal thickness, retinal volume at 3- and 5-mm central circles, RPE elevation, the size of the fluid area, and age of the patient (r > 0.70, p < 0.05), whereas in group 2; logMAR BCVA was strongly correlated only with foveal volume (r = 0.74, p = 0.01). Multivariate analysis showed that post-injection FVL size (r (2) = 0.69) and foveal volume (r (2) = 0.55) were the most important factors for VA 1 month following the initial and repeated ranibizumab injection, respectively.

CONCLUSIONS

The size of FVL and foveal volume showed a significant correlation with VA in AMD patients shortly after the first and repeated ranibizumab injection, respectively. Further studies with larger sample sizes are needed in order to support these results.

Vitrectomy for exudative age-related macular degeneration with vitreous hemorrhage

PURPOSE

The purpose of this study was to study the effect of pars plana vitrectomy (PPV) for age-related macular degeneration with vitreous hemorrhage on choroidal neo-vascularization (CNV).

METHODS

A retrospective interventional case series in which 92 eyes with age-related macular degeneration with vitreous hemorrhage that received PPV were studied. Among them, 60 eyes without pre- or posttreatment other than PPV were selected. Choroidal neovascularization was expressed as the incidence of bleeding 6 months before and after PPV. The status of CNV after PPV was compared and classified as worsened, remained, regressed, disappeared, or unclassified. The influence of posterior vitreous detachment was examined.

RESULTS

The incidence of bleeding was reduced dramatically after PPV (1.11 +/- 0.44 in preoperative 6 months vs. 0.03 +/- 0.18 in postoperative 6 months, P < 0.0001). The status of CNV improved in most cases; 40 of 54 classifiable eyes (74.1%) were categorized as "regressed" or "disappeared." Postoperative visual acuity was significantly better than preoperative visual acuity (P < 0.0001). The status of CNV subsided more in those eyes without posterior vitreous detachment than in those with posterior vitreous detachment (odds ratio, 1.02; 95% confidence interval, -0.01-2.08; P = 0.054).

CONCLUSION

The activity of CNV was reduced after PPV in eyes with age-related macular degeneration with vitreous hemorrhage. Visual acuity significantly improved, with only rare severe complications. The involvement of vitreomacular traction in the patho-physiology of CNV in age-related macular degeneration is possible.

Evaluation of artifacts associated with macular spectral-domain optical coherence tomography

PURPOSE

To characterize the types and frequencies of image artifacts associated with macular scanning using 2 common spectral-domain optical coherence tomography (SD OCT) instruments and to evaluate the impact of artifacts on foveal thickness measurements.

DESIGN

Retrospective, observational chart review.

PARTICIPANTS

For the Cirrus HD-OCT (Carl Zeiss Meditec, Dublin, CA), scans of 98 eyes from 58 patients were included in the study. For the Spectralis HRA+OCT (Heidelberg Engineering, Heidelberg, Germany), scans of 88 eyes from 54 patients were included.

METHODS

Macular volume scans of healthy and diseased eyes were evaluated systematically for image artifacts within each scan overall and within the center 1-mm area. The frequency of each artifact type was compared for scans stratified by diagnosis category. Artifacts in the center 1-mm area were graded for severity and were corrected manually using each instrument's software. Artifacts that resulted in errors of more than 50 microm or more than 10% of retinal thickness or that caused a misdiagnosis of macular edema or retinal thinning were defined as clinically significant and were analyzed further.

MAIN OUTCOME MEASURES

Overall frequency of image artifacts by artifact type, relative frequency of artifacts in scans stratified by posterior segment disease diagnosis, and retinal thickness measurements of the center 1-mm subfield before and after artifact corrections.

RESULTS

For Cirrus, 84.7% of scans had artifacts and 32.7% had at least 1 artifact in the center 1-mm area of the scan. For Spectralis, 90.9% of scans had at least 1 artifact, and 37.5% had at least 1 artifact in the center 1-mm area. Certain artifact types were observed more frequently with specific disease states. Clinically significant artifacts involving the center 1-mm area were seen in 5.1% of Cirrus and 8.0% of Spectralis scans.

CONCLUSIONS

Image artifacts in SD OCT volume scanning are common and frequently involve segmentation errors. Artifacts are relatively less common in the center 1-mm area of scans, but may affect retinal thickness measurements in a clinically significant manner. Careful review of scans for artifacts is important when using SD OCT images and retinal thickness measurements in patient care or clinical trials.

Changes in visual function and thickness of macula after photodynamic therapy for age-related macular degeneration

PURPOSE

To determine the correlation between the changes in the central retinal sensitivity and the changes in the foveal thickness (FT) after photodynamic therapy (PDT) for age-related macular degeneration (AMD).

METHODS

Nineteen eyes of 19 patients with choroidal neovasularizations (CNVs) secondary to AMD were studied. The pretreatment values of the central retinal sensitivity determined by Micro Perimeter 1 (MP1; Nidek Technologies), best-corrected visual acuity (BCVA), and optical coherence tomography (OCT)-determined FT were compared to the postoperative values at three and six months after PDT.

RESULTS

At six months, the retinal sensitivity within the central 10 degrees was significantly improved (P = 0.02) and the FT was significantly thinner (P = 0.016). The BCVA, however, did not change significantly (P = 0.80). The changes in the retinal sensitivities were significantly correlated with the changes in the decrease in the FT (r = - 0.59, P = 0.012 within the central 10 degrees ) at six months after PDT.

CONCLUSION

Significant improvements in retinal sensitivities within the central 10 degrees and a decrease in FT were observed even though the BCVA was not significantly improved. The measurement of retinal sensitivity by MP1 may be a better method to assess central visual function than the conventional visual acuity after PDT.

[Optical coherence tomography for macula diagnostics. Review of methods and standardized application concentrating on diagnostic and therapy control of age-related macula degeneration]

BACKGROUND

Optical coherence tomography (OCT) has gained increasing relevance for follow-up after the treatment of macular diseases especially after anti-VEGF therapy. Therefore it seemed reasonable to develop standardized evaluation strategies and OCT examination guidelines for Stratus OCT III.

MATERIALS AND METHODS

Basic guidelines for the Stratus OCT III examination of macular diseases were developed. The first part contains basic advice for the OCT examination with respect to the examiner, patients, image quality, movement artefacts, algorithms, archiving and interpretation of OCT images. The second part consists of the relevance and indications for OCT examination especially in age-related macular degeneration (AMD), subgroups of AMD and follow-up after treatment. The third part demonstrates a brief outlook on future developments, such as the digital integration method (DIM), which provides identical scan localization in follow-up and eliminates any movement artefacts.

CONCLUSION

The application of standardized routine scanning and analysis protocols in Stratus OCT III for macular diseases and follow-up examinations provides an optimized, time-saving and comparable use of OCT. Therefore, the relevance and quality of OCT is increased for routine use in outpatient departments, hospitals and also for clinical studies.

Association between foveal photoreceptor integrity and visual outcome in neovascular age-related macular degeneration

PURPOSE

To evaluate the correlation between visual outcome and foveal photoreceptor integrity after successful treatment of eyes with neovascular age-related macular degeneration (AMD).

DESIGN

Retrospective chart review.

METHODS

We retrospectively studied the medical records of 51 eyes of 51 patients with neovascular AMD who were treated successfully with photodynamic therapy (PDT). All eyes were followed-up for more than 24 months after the initial treatment. Using spectral-domain optical coherence tomography, the status of the inner segment and outer segment (IS/OS) photoreceptor junction was assessed as a hallmark of the integrity of the foveal photoreceptor layer.

RESULTS

At the final visit, no eyes showed an exudative change. A complete or discontinuous IS/OS line was detected beneath the fovea in 8 (15.7%) and 25 (29.4%) eyes, respectively, whereas 28 (54.9%) had no IS/OS line. Eyes with a continuous or discontinuous IS/OS line beneath the fovea had better final visual acuity (VA) than did eyes without an IS/OS line (P < .001, respectively). Of the 51 eyes, 36 showed polypoidal choroidal vasculopathy (PCV), whereas 15 were diagnosed as having typical AMD without PCV. Visual outcome was significantly better in eyes with PCV (P = .026). Most eyes (13/15; 86.7%) with typical AMD had no IS/OS line at the final visit, whereas only 13 (36.1%) of the 36 eyes with PCV had no IS/OS line beneath the fovea.

CONCLUSIONS

Integrity of the photoreceptor layer beneath the fovea is associated with the final VA in neovascular AMD after successful PDT.

Intravitreal bevacizumab (Avastin) for neovascular age-related macular degeneration using a variable frequency regimen in eyes with no previous treatment

PURPOSE

To evaluate a variable frequency regimen with intravitreal bevacizumab for treatment of neovascular age-related macular degeneration (AMD) in eyes that have not received any previous treatment.

METHODS

Retrospective review of patients with neovascular AMD who were treated with three consecutive monthly intravitreal injections of bevacizumab (1.25 mg) and retreated based on the PrONTO study criteria. Outcome measures included visual acuity (VA) and central retinal thickness. Subgroup analysis was conducted to identify pretreatment characteristics that could determine visual outcome with treatment.

RESULTS

A total of 109 eyes of 109 patients were treated. The mean age was 82 years, and the mean follow-up period was 9.4 months (range 6-12 months). At baseline, the mean VA was 45.6 letters (6/37.5) and mean central retinal thickness 343 microm. This improved to 51 letters (6/30) (P < 0.001)) and 231 microm (P < 0.001) at 6 months. At 6 months, VA was improved by at least five letters in 50%, remained stable in 30% and worsened by at least five letters in 20% of patients. Patients with large intraretinal cysts on optical coherence tomography before treatment had an increased risk of worse vision (odds ratio 10.5, 95% confidence interval 1.69-64.99; P = 0.018).

CONCLUSIONS

The majority of patients had improvement or stability of VA regardless of the angiographic type of choroidal neovascularization. Intravitreal bevacizumab with this tailored regimen is beneficial in the treatment of neovascular AMD in the short term. The presence of large intraretinal cysts on optical coherence tomography is a poor prognostic factor for visual improvement with this treatment.

Photodynamic therapy with verteporfin in age-related macular degeneration: a systematic review of efficacy, safety, treatment modifications and pharmacoeconomic properties

Photodynamic therapy (PDT) with verteporfin has been used less comprehensively in the treatment of exudative age-related macular degeneration (AMD), and specifically of choroidal neovascularization (CNV), since the advent of antiangiogenic therapies. Recently, there has been a renewed interest in PDT as an adjunct to these and other agents in the treatment of neovascular AMD. In light of this new development and the European Medicines Evaluation Agency's (EMEA) recent labelling decision to rescind approval for the use of PDT in occult CNV lesions, the present systematic review was undertaken to revisit the evidence supporting its clinical application. Photodynamic therapy provided the first pharmacological treatment for patients suffering from subfoveal CNV, the major cause of severe vision loss in AMD. Key clinical trials evaluating efficacy and safety have examined patients with all lesion subtypes, with the primary labelled indication (i.e. lesions containing a classic component of > or = 50% ) deriving from the results of the Treatment of Age-related Macular Degeneration with Photodynamic Therapy (TAP) Study. The subsequent TAP Study Group post hoc categorization of lesions as predominantly classic is open to question, however, as it appears that the overall efficacy in this group only may have reflected the especially strong response in 100% classic lesions. Based on a subgroup analysis of the Verteporfin in Photodynamic Therapy Study, the indication for PDT subsequently was expanded in some jurisdictions, including that of the EMEA, to include occult lesions with no classic component. However, the subsequent Visudyne in Occult Study found no benefit in 100% occult lesions, resulting in the EMEA rescinding its approval for this indication.

Relationships between clinical measures of visual function and anatomic changes associated with bevacizumab treatment for choroidal neovascularization in age-related macular degeneration

PURPOSE

This pilot study was undertaken to examine the relationships between clinical measures of visual function and anatomic changes occurring in the eyes treated with bevacizumab for choroidal neovascularization (CNV) due to age-related macular degeneration (AMD).

METHODS

A retrospective review was conducted for 50 eyes that had been treated with at least three injections of bevicizumab for CNV due to AMD, and followed for at least 6 months. Vision outcomes included best-corrected ETDRS chart acuity, scored by best-line read (ETDRS line) and by total letters read (ETDRS letter), and two measures obtained from central acuity perimetry with 98% Michelson contrast targets, the best acuity within 6 degrees of fixation (BA6 degrees ), and global macular acuity (GMA), representing a weighted average of the acuities thresholded at all intercepts within a 10 degrees radius of fixation. Assessment of anatomic outcomes included fibrosis, atrophy, and subretinal hemorrhage grading on fundus photography, CNV size, pigment epithelial detachment (PED) size and grading of CNV leakage on fluorescein angiography, and central retinal PED, and subretinal fluid (SRF) thickness on optical coherence tomography.

RESULTS

Logistic regression analysis showed an association between the vision outcomes of EDTRS letter and BA6 degrees with the change in SRF thickness (R (2): 0.47 and 0.35, respectively). The outcome of the vision measurement of GMA was associated with the change in SRF thickness, in CNV thickness, and in CNV fibrosis grade (R (2): 0.34). No association was noted between the outcomes of ETDRS line with the change in any anatomic outcomes.

CONCLUSION

Acuity perimetry outcomes in this study seemed to offer improved understanding of the relationship between the vision outcomes and the measured anatomic changes. It seemed that neither ocular coherence tomography nor fluorescein angiography alone offered sufficient morphologic markers for prediction of functional outcomes.

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.

Vitreomacular traction and exudative age-related macular degeneration

Vitreomacular traction resulting from lacking, incomplete or anomalous posterior vitreous detachment is suspected to play a crucial role in the pathogenesis of different forms of age-related macular degeneration (AMD) along with the known mechanisms. It is probable that the fundamental pathomechanisms of AMD formation have already begun by the time tractional forces lead to a change for the worse. Vitreomacular traction alone is perhaps not able to induce AMD. It would seem sensible to consider vitreous changes when diagnosing and treating AMD patients because of the high coincidence of vitreomacular traction and choroidal neovascularization (CNV) and the often successful treatment of other diseases of the vitreoretinal interface by vitrectomy. The concept of the pathogenesis of AMD should therefore be extended to include the influence of the vitreous, especially where therapeutic concepts such as pharmacological vitreolysis and vitreous separation have been established as causative treatment of late forms of AMD.

Clinical applications and new developments of optical coherence tomography: an evidence-based review

Optical coherence tomography (OCT) is a new imaging modality that has increasingly become an indispensable tool in clinical practice for the diagnosis and management of ocular diseases involving the macula, optic nerve and anterior segment. The instrument is an advanced imaging technique that provides unprecedented high resolution and cross-sectional tomographic images of the ocular microstructure in situ, and in real time. Since its introduction about four years ago, a multitude of advantages has made OCT an essential instrument in ophthalmic imaging. The technique has fast image acquisition speed and non-contact, non-invasive applicability, allowing a non-excisional 'optical biopsy' to be performed. The purpose of this paper is to provide an evidence-based review of the increasing role of OCT in the diagnosis and management of ocular disorders, particularly in age-related macular degeneration, diabetic macular oedema, macular hole, epiretinal membrane and glaucoma. Being one of the first users of OCT in Australia, our clinical experiences will be highlighted and clinical examples of various conditions will be presented to provide an overview of the immense implications of OCT in practice. The latest developments of the OCT revolution, in relation to combining OCT with fundus photography and scanning laser ophthalmoscopy, will also be described. New developments of three-dimensional visualisation of tissue morphology with future models of ultra-high speed, ultra-high resolution OCT may further enhance the early diagnosis, monitoring of disease progression and assessment of treatment efficacy, facilitated by this powerful technology.

Optical coherence tomography: a review of clinical development from bench to bedside

Since its introduction, optical coherence tomography (OCT) technology has advanced from the laboratory bench to the clinic and back again. Arising from the fields of low coherence interferometry and optical time- and frequency-domain reflectometry, OCT was initially demonstrated for retinal imaging and followed a unique path to commercialization for clinical use. Concurrently, significant technological advances were brought about from within the research community, including improved laser sources, beam delivery instruments, and detection schemes. While many of these technologies improved retinal imaging, they also allowed for the application of OCT to many new clinical areas. As a result, OCT has been clinically demonstrated in a diverse set of medical and surgical specialties, including gastroenterology, dermatology, cardiology, and oncology, among others. The lessons learned in the clinic are currently spurring a new set of advances in the laboratory that will again expand the clinical use of OCT by adding molecular sensitivity, improving image quality, and increasing acquisition speeds. This continuous cycle of laboratory development and clinical application has allowed the OCT technology to grow at a rapid rate and represents a unique model for the translation of biomedical optics to the patient bedside. This work presents a brief history of OCT development, reviews current clinical applications, discusses some clinical translation challenges, and reviews laboratory developments poised for future clinical application.

Optical coherence tomography analysis of a randomized study combining photodynamic therapy with intravitreal triamcinolone

BACKGROUND

The objective of the study was to analyze optical coherence tomography (OCT) scan differences between patients with predominantly classic subfoveal choroidal neovascularization (CNV) secondary to age-related macular degeneration (AMD) treated with only photodynamic therapy (PDT) and patients treated with PDT combined with intravitreal triamcinolone acetonide (IVTA).

METHODS

In this prospective study, 61 patients were randomized to receive PDT (n = 30) or PDT combined with IVTA (n = 31). They were evaluated every 3 months with a refraction protocol for best-corrected visual acuity (VA) measured with Early Treatment Diabetic Retinopathy Study (ETDRS) charts, fluorescein angiography (FA), and OCT. When measuring foveal thickness on OCT scans, neuroretinal foveal thickness (NFT) was differentiated from outer high reflectivity band thickness (OHRBT). The main outcome measures were mean change in OCT measurements and correlation of VA and angiographic area of the lesion with OCT measurements.

RESULTS

At the 12-month follow-up, the mean change in NFT was not significantly reduced (P = 0.9), but the mean change in OHRBT was significantly lower (P = 0.004) in the group of patients who received combined therapy. There was no correlation between final VA and NFT in either patient group (P = 0.2). The final VA was significantly worse in eyes with a thicker OHRBT (P = 0.04) in the group of patients treated with only PDT. There was no correlation between angiographic area and NFT and OHRBT in either patient group (P > 0.3). There was a statistically significant difference between the pre-treatment angiographic area of the lesion and VA at the 12-month follow-up in the combined therapy group (P = 0.01), and more eyes treated with only PDT presented with intraretinal fluid at the last follow-up (P = 0.01).

CONCLUSION

Combined PDT+IVTA therapy was more effective than PDT alone at reducing OHRBT. This OCT measurement seems to be have a greater effect on VA than NFT.

Zinc Phthalocyanine Tetrasulfonate (ZnPcS4): A New Photosensitizer for Photodynamic Therapy in Choroidal Neovascularization

PURPOSE

The aim of this sutdy was to demonstrate the selective localization of a new photosensitizer, zinc phthalocyanine tetrasulfonate (ZnPcS(4)), in rat eyes and investigate the ability of ZnPcS(4) to produce a photochemical closure of experimental choroidal neovascularization (CNV) upon irradiation with a 670-nm laser light.

METHODS

To determine the biodistribution of ZnPcS(4) and the optimal timing of laser irradiation after photosensitizer administration, fluorescence microscopy with ZnPcS(4) was performed. CNV was created in the fundi of Brown-Norway rats using the argon laser model and documented by fluorescein angiography (FFA) and optical coherence tomography (OCT). Photodynamic therapy (PDT) was performed at the dose of 2.0 mg/m(2) and laser fluences of 600 mW/cm(2) on the CNV and on normal retina and choroid. Treatment outcomes were assessed by FFA and OCT and confirmed by light and electron microscopy.

RESULTS

Fluorescence microscopy demonstrated intense ZnPcS(4) fluorescence from the CNV, choriocapillaris, and retinal pigment epithelial cells. Peak ZnPcS(4) intensities in the choriocapillaris and CNV were detected at 10-20 min after an intravenous injection. FFA and OCT indicated that irradiation with 670 nm of laser light 20 min after a ZnPcS(4) injection produced a complete closure of CNV with minimal damage to the overlying retina. Histologic studies, using light and electron microscopy, demonstrated CNV endothelial cell necrosis with minimal damage to the surrounding tissues.

CONCLUSIONS

ZnPcS(4) selectively localizes to the choriocapillaris and CNV in rats, resulting in the occlusion of laser-induced CNV with minimal damage to the retina tissues. ZnPcS(4) -PDT is a potential new strategy for the treatment of macular degeneration and other human diseases manifesting as CNV.

A Comparison of Structural Measurements Using 2 Stratus Optical Coherence Tomography Instruments

PURPOSE

To compare measures of peripapillary retinal nerve fiber layer (RNFL) thickness, optic disc topography, and central foveal thickness generated using 2 different Stratus optical coherence tomography (OCT) instruments.

METHODS

Ten normal subjects and 10 glaucoma subjects were included. One randomly selected eye per subject was scanned consecutively using a fast RNFL thickness protocol, fast macular thickness map, and fast optic disc protocol by 2 experienced operators on 2 instruments. The order of the machines and operators were randomized. The output power of each machine was measured using an optical power meter. For each OCT measurement 2 factor fixed effects analyses of variance were performed and a restricted maximum likelihood variance component analysis of the proportion of variance due to subject, operator, and machine was calculated.

RESULTS

Significant differences (P<or=0.003) between OCT instruments were observed in average, superior, and inferior RNFL thickness and central foveal thickness values among normal eyes; and average and superior RNFL thickness and cup/disc area ratio values among glaucomatous eyes. Overall, the intermachine variability (0.0% to 16.4%) was larger than the interoperator variability (0.0% to 2.4%) for all OCT measurements. In the glaucoma group the variability due to machine differences was 2.6 microm for the average RNFL thickness, 5.7 microm for the superior RNFL thickness, 0 microm for the inferior RNFL thickness, 0.03 microm for the cup/disc area ratio, 0.01 microm for the cup/disc vertical ratio, and 2.8 microm for the average foveal thickness.

CONCLUSIONS

Measurements of RNFL thickness, optic disc topography, and central foveal thickness significantly differ between OCT instruments.

Surgical treatment of age-related macular degeneration: will there be a role in the future?

Surgical treatment has been shown to be able to improve vision that is lost as a result of age-related macular degeneration. Surgery is complex, such that improvement has always to be weighed against risk of complications. The availability of Ranibizumab and Bevacizumab is set to dramatically alter our management options. Surgical treatment will have a limited role to play in the next few years.

Optical coherence tomography on autologous translocation of choroid and retinal pigment epithelium in age-related macular degeneration

PURPOSE

To analyse structural changes after autologous translocation of choroid and retinal pigment epithelium (RPE) in patients with age-related macular degeneration (AMD) using optical coherence tomography (OCT).

METHODS

We performed a prospective nonrandomised study in 29 consecutive patients, who underwent submacular surgery with translocation of an autologous full-thickness graft of RPE, Bruch's membrane, and choroid. All patients had recent loss of reading vision due to AMD. OCT was performed before surgery and at 3- and 6- month follow-up to analyse the morphological appearance of the graft and the overlying retina.

RESULTS

Maximum retinal thickness decreased from mean 408 microm (standard deviation (SD) 127 microm) preoperative to mean 373 microm (SD 104 microm) at 6-month follow-up (P=0.094). In 11 cases (40%), a nearly physiological shape of the retina was seen at this time point. A macular hole persisted in two eyes after silicone oil removal. In most eyes, the highly reflective band of the graft presumably corresponding to RPE was continuous with the surrounding RPE band in all six OCT scans. Eyes with flat appearance of the graft at 6-month follow-up (<300 microm) showed a significantly better functional outcome than eyes with more prominent grafts. Interestingly, most patients did not complain about metamorphopsia, even though the graft was prominent or wrinkled in some cases.

CONCLUSION

OCT is a useful tool in monitoring intra- and subretinal changes after subretinal surgery with graft translocation. We demonstrated that graft translocation may lead to a normalisation of retinal thickness and stabilisation of visual acuity.

Short-term effects of focal argon laser treatment in diabetic maculopathy as demonstrated by optical coherence tomography

PURPOSE

To assess the short-term effects of argon laser on retinal thickening as demonstrated by optical coherence tomography (OCT).

METHODS

A prospectively collected consecutive series of patients undergoing routine focal argon laser treatment for sight-threatening diabetic maculopathy had bilateral OCT performed before laser treatment and 1 hour, 24 hours, and 2 weeks after treatment. The main outcome measure was change in retinal thickness in the region of laser treatment.

RESULTS

Forty-six eyes were analyzed. There was a small increase in retinal thickness in the treated area 1 hour after laser treatment, with a mean change from before laser treatment of +2.6 microm (95% confidence interval [CI], +0.2 to + 5.0). However, there was a larger change 24 hours after treatment of +39.0 microm (95% CI, +31.6 to + 46.4) and a significant decrease 2 weeks after treatment of -14.6 microm (95% CI, -21.6 to -7.7) from before laser treatment values.

CONCLUSION

Focal argon laser treatment remains the first-line treatment for sight-threatening diabetic maculopathy. This study shows that in the short-term, areas of retinal thickening worsen before settling in response to argon laser treatment as demonstrated by OCT.

Fluorescein Angiography Compared to Three-Dimensional Measurements by the Retinal Thickness Analyzer in Classic Choroidal Neovascularization

PURPOSE

To compare and correlate imaging of classic subfoveal choroidal neovascularization (CNV) with noninvasive 3-dimensional imaging by the retinal thickness analyzer (RTA) to conventional fluorescein angiography (FA).

METHODS

A total of 29 eyes of 29 consecutive patients with predominantly classic CNV eligible for photodynamic therapy underwent FA and RTA imaging. The FA dimensions of the CNV were measured independently by two graders. With the RTA, masked to FA the size of the CNV itself as imaged in 3-dimensional reconstruction, the size of significantly thickened retina overlying the CNV and the maximum retinal thickness were measured.

RESULTS

The mean diameter of the CNV determined from 3-dimensional RTA reconstructions showed an excellent correlation with measurements from FA (r = 0.91, p < 0.001). The area of retinal thickening was by a mean of 0.7 mm in diameter larger and correlated moderately well with the size of the CNV on FA (r = 0.65, p < 0.001). In contrast, there was no correlation between the absolute retinal thickness and the CNV size on FA.

CONCLUSIONS

Noninvasive quantitative mapping of predominantly classic CNV by RTA is feasible and also allows 3-dimensional measurement of the lesion itself. The results correlate well with FA assessment but visualize different properties of the disease.

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.

Alignment artifacts in optical coherence tomography analyzed images

PURPOSE

To compare retinal thickness and retinal height of the original scanned optical coherence tomography (OCT) images with those of the same images after automated retinal thickness analysis.

DESIGN

Cross-sectional study.

PARTICIPANTS

Thirty normal eyes, 20 eyes with neovascular age-related macular degeneration (AMD), 20 with central serous chorioretinopathy (CSC), 20 with macular holes, and 20 with non-AMD related macular edema from 110 subjects were selected randomly from an OCT database. One of the 6 macular scans in each eye was chosen randomly for analysis.

METHODS

Two sets of OCT images--original images and analyzed images (after retinal thickness [single eye] analysis)--in each eye were exported for retinal thickness or retinal height measurement. Comparisons of retinal thickness or retinal height at selected locations were performed.

MAIN OUTCOME MEASURES

Retinal thickness (defined as the distance between the anterior boundary of the retinal nerve fiber layer [RNFL] and posterior boundary of the photoreceptor layer) and retinal height (defined as the distance between the anterior boundary of the RNFL and baseline level of the anterior boundary of the retinal pigment epithelium [RPE]). Retinal height was measured when there was detachment of neurosensory retina or RPE.

RESULTS

No significant difference in retinal thickness was observed between the original and the analyzed OCT images in normal eyes and in eyes with macular holes or non-AMD related macular edema. However, OCT-analyzed images demonstrated retinal thickness or retinal height measurements in eyes with CSC or neovascular AMD significantly lower than the corresponding measurements in the original images (all with Ps< or =0.001, Wilcoxon signed rank test). In the groups of neovascular AMD and CSC, Bland-Altman plots revealed mean differences of 124 mum (95% limits of agreement between -65.5 and 313.6) and 84.4 mum (95% limits of agreement between -178.0 and 346.8), respectively, between the original and analyzed retinal measurements.

CONCLUSIONS

Retinal thickness and retinal height could be underestimated in patients with CSC or neovascular AMD after retinal thickness analysis in Stratus OCT when either automatic measurements or manual caliper-assisted measurements are performed on the analyzed images. We recommend exporting the original scanned OCT images for retinal thickness and retinal height measurement in patients with CSC or neovascular AMD.

Doppler optical coherence tomography to monitor the effect of photodynamic therapy on tissue morphology and perfusion

We investigated the feasibility of using optical coherence tomography (OCT) for noninvasive real-time visualization of the vascular effects of photodynamic therapy (PDT) in normal and tumor tissue in mice. Perfusion control measurements were initially performed after administrating vaso-active drugs or clamping of the subcutaneous tumors. Subsequent measurements were made on tumor-bearing mice before and after PDT using the photosensitizer meta-tetrahydroxyphenylchlorin (mTHPC). Tumors were illuminated using either a short drug light interval (D-L, 3 h), when mTHPC is primarily located in the tumor vasculature or a long D-L interval (48 h), when the drug is distributed throughout the whole tumor. OCT enabled visualization of the different layers of tumor, and overlying skin with a maximal penetration of < or =0.5-1 mm. PDT with a short D-L interval resulted in a significant decrease of perfusion in the tumor periphery, to 20% of pre-treatment values at 160 min, whereas perfusion in the skin initially increased by 10% (at 25 min) and subsequently decreased to 60% of pre-treatment values (at 200 min). PDT with a long D-L interval did not induce significant changes in perfusion. The concept of using noninvasive OCT measurements for monitoring early, treatment-related changes in morphology and perfusion may have applications in evaluating effects of anti-angiogenic or antivascular (cancer) therapy.

The Role of Optical Coherence Tomography (OCT) in the Diagnosis and Management of Retinal Angiomatous Proliferation (RAP) in Patients with Age-related Macular Degeneration

Introduction: The aim of this review was to describe the use of optical coherence tomography (OCT) in the diagnosis and management of retinal angiomatous proliferation (RAP) in patients with age-related macular degeneration (AMD). Materials and Methods: We reviewed the tomographic characteristics of the eyes affected by RAP seen at our institution and imaged by OCT. Some eyes with RAP were also studied with OCT prior to and after laser treatment to determine the tomographic changes following laser photocoagulation. Results: In this preliminary report, OCT showed a typical pattern of structural changes in RAP: increased foveal thickness, cystoid macular oedema (CME) consisting of large central cysts and smaller cystoid spaces located mainly in the outer retinal layers, serous retinal detachment and a highly reflective intraretinal mass overlying a highly or moderately elevated retinal pigment epithelium (RPE). This mass corresponded to the hot spot observed on ICG angiography. After successful laser photocoagulation, significant decrease in foveal thickness, complete resolution of CME and retinal detachment with thinning of the neurosensory retina overlying the treated area could be observed. Conclusions: OCT appears to be useful in evaluating and documenting RAP in AMD patients both before and after laser photocoagulation. Longitudinal studies are required to determine its exact place and utility in clinical practice. Key words: Choroidal neovascularisation, Laser coagulation, Retinal imaging

Retinal assessment using optical coherence tomography

Over the 15 years since the original description, optical coherence tomography (OCT) has become one of the key diagnostic technologies in the ophthalmic subspecialty areas of retinal diseases and glaucoma. The reason for the widespread adoption of this technology originates from at least two properties of the OCT results: on the one hand, the results are accessible to the non-specialist where microscopic retinal abnormalities are grossly and easily noticeable; on the other hand, results are reproducible and exceedingly quantitative in the hands of the specialist. However, as in any other imaging technique in ophthalmology, some artifacts are expected to occur. Understanding of the basic principles of image acquisition and data processing as well as recognition of OCT limitations are crucial issues to using this equipment with cleverness. Herein, we took a brief look in the past of OCT and have explained the key basic physical principles of this imaging technology. In addition, each of the several steps encompassing a third generation OCT evaluation of retinal tissues has been addressed in details. A comprehensive explanation about next generation OCT systems has also been provided and, to conclude, we have commented on the future directions of this exceptional technique.

Correlation of optical coherence tomography and fundus fluorescein angiography following photodynamic therapy for choroidal neovascular membranes

AIMS

To assess the correlation between optical coherence tomography (OCT) and leakage on fundus fluorescein angiography (FFA) following photodynamic therapy (PDT) with verteporfin for choroidal neovascularisation (CNV).

METHODS

Retrospective comparative observational case series of patients who were treated with PDT for CNV from one centre. All patients had 3 monthly FFA and OCT following initial PDT to assess if further treatment was required. A pair of FFA and OCT images from the same visit at a random follow up date were taken from each patient's series and assessed separately by different observers. The presence of pigment epithelial detachment, subretinal fluid, vitreomacular traction, intraretinal fluid, absence of foveal depression, and the retinal thickness on OCT were correlated with presence of leaks on FFA.

RESULTS

A total of 121 eyes of 121 patients were included. The presence of subretinal fluid, gross cystoid macular oedema, sponge-like retinal thickening and retinal thickness of more than 350 mum on OCT correlated well with leak on FFA (p value <0.01). The likelihood ratios were 3.0, 5.7, 2.7, and 3.6, respectively. The presence of a solitary foveal cyst did not correlate well with leaks on FFA.

CONCLUSIONS

The presence of subretinal fluid, intraretinal fluid in the form of gross cystoid macular oedema, or sponge-like retinal thickening, or a retinal thickness more than 350 mum correlates with leaks on FFA and so suggests the need for repeat PDT.

Early optical coherence tomography changes after photodynamic therapy in patients with age-related macular degeneration

PURPOSE

To evaluate early changes after photodynamic therapy (PDT) in patients with age-related macular degeneration (AMD) by optical coherence tomography (OCT).

DESIGN

Prospective interventional case series.

METHODS

PDT was performed on 20 eyes of 20 patients who presented with subfoveal choroidal neovascularization (CNV) attributable to AMD. OCT was used to evaluate changes at 2, 12, and 24 hours and at 3, 7, 15, and 30 days after therapy.

RESULTS

In the first 24 hours, OCT showed an increase in the subretinal fluid (SF) in all eyes and an increase in intraretinal fluid (IF) in 13 eyes. On the 15th day and the 30th day after therapy, reduction of SF and IF was observed in almost all eyes.

CONCLUSIONS

Serial OCT evaluation of patients with subfoveal CNV attributable to AMD suggests that the initial response after PDT is an increase in SF and IF.

Optical coherence tomography to monitor photodynamic therapy in pathological myopia

AIM

To evaluate the role of optical coherence tomography (OCT) in determining choroidal neovascularisation (CNV) activity before and after photodynamic therapy (PDT) in patients with pathological myopia.

METHODS

33 patients (33 eyes) with pathological myopia and being treated with PDT were included. Every 3 months all patients were evaluated and presence or absence of leakage on fluorescein angiography, presence of intraretinal or subretinal fluid on OCT, and macular and choroidal neovascular complex thickness on OCT, were determined at each examination.

RESULTS

The macular thickness decreased significantly after PDT at 6 months (p = 0.001) and at 12 months follow up (p = 0.01). However, no significant changes in CNV thickness were measured after PDT at 6 months of follow up (p = 0.418) and at 12 months of follow up (p = 0.521). Once the diagnosis of CNV associated with pathological myopia was established, before treatment, OCT had a sensitivity of 96.96% for detecting CNV activity. After treatment, OCT had a good sensitivity (95.23%) and a moderate specificity (69,69%) in determining CNV activity, which resulted in a diagnostic efficiency (proportion of correct results) of 79.62%.

CONCLUSIONS

OCT appears to be useful for indicating CNV activity. Therefore, it may serve as a complementary technique for deciding the need for PDT and re-treatment in patients with pathological myopia.