The feasibility of clinical evaluation for anterior uveitis through spectral-domain optical coherence tomography in dogs

OBJECTIVE

To evaluate the clinical application of spectral-domain optical coherence tomography (SD-OCT) for anterior uveitis in dogs.

ANIMALS AND PROCEDURES

Client-owned dogs presenting with anterior uveitis and clinically healthy dogs were enrolled in this study. Included eyes were divided into 5 groups by flare grade and 3 groups by cell grade through slit-lamp biomicroscopy. Each eye was examined using SD-OCT following slit-lamp biomicroscopy. The ratio of aqueous signal intensity to air signal intensity, which is called the aqueous-to-air relative intensity (ARI) index, was used to evaluate the flare grade. Cell number, central corneal thickness (CCT), and the presence of keratic precipitates (KPs) were analyzed on SD-OCT. The OCT parameters, including ARI index, cell number, and CCT, were compared to the slit-lamp clinical flare and cell grade.

RESULTS

Thirty-six eyes with anterior uveitis and 27 healthy eyes were enrolled. The ARI index showed a significant correlation with clinical flare grade (r_s  = 0.811, p < .001). In multiple regression analysis, the ARI index and CCT showed a significant negative correlation (r = -0.258, p = .044). The number of cells on SD-OCT significantly increased with cell grade on slit-lamp biomicroscopy (r_s  = 0.653, p < .001). The clinical flare grade and CCT were significantly correlated in the partial correlation analysis after controlling for age (partial correlation coefficient = 0.471, p = .002). KPs were observed in 61% of the eyes with flare using SD-OCT (22/36 eyes).

CONCLUSIONS

Spectral-domain optical coherence tomography could provide quantitative information, including the ARI index, cell counts, and CCT in dogs. SD-OCT is an auxiliary modality for slit-lamp biomicroscopy when evaluating anterior uveitis in dogs.

Multifocal visual evoked potential for evaluation of open-angle glaucoma

Background

To correlate multifocal visual evoked potential (mfVEP) findings with static automated perimetry (SAP) and spectral-domain optical coherence tomography (SD-OCT) in eyes with primary open- angle glaucoma (POAG).

Methods

This cross-sectional study included a consecutive sample of 40 eyes of 40 patients with POAG. The participants underwent a complete ophthalmologic assessment, axial length (AL) measurement, and assessments with SAP, SD-OCT, and mfVEP.

Results

POAG cases were aged 49.70 (14.16) years (mean [SD]) and most were females (n = 24, 60%). For eyes of patients with POAG, the mfVEP upper-ring signal-to-noise ratio (SNR) showed a significant negative correlation with best-corrected logMAR visual acuity (r = - 0.33; P = 0.038), and a significant positive correlation with the superior hemifield of the visual field (VF) and the inferior-quadrant retinal nerve fiber layer (RNFL) thickness (r = + 0.34; P = 0.030; r = + 0.51; P < 0.001, respectively). Similarly, the mfVEP lower-ring SNR showed a significant negative correlation with best-corrected logMAR visual acuity (r = - 0.36; P = 0.024) and a significant positive correlation with the inferior hemifield of the VF and superior quadrant RNFL thickness (r = + 0.55; P < 0.001 and r = + 0.70; P < 0.001, respectively).

Conclusions

mfVEP is a promising tool for objective assessment of the VF in patients with POAG, as it is positively correlated with the VF and OCT RNFL thickness. Future longitudinal studies with a larger sample size and a specific glaucoma subtype, along with multiple follow-up evaluations, are warranted to confirm our preliminary results.

Evaluation of the upper and lower proximal lacrimal canaliculi using spectral-domain optical coherence tomography in normal Beagle dogs

OBJECTIVE

To confirm the feasibility of visualizing upper and lower proximal lacrimal canaliculi (LC) using spectral-domain optical coherence tomography (SD-OCT).

ANIMALS STUDIED

Eight eyes of four normal Beagle dogs.

PROCEDURES

To obtain an upper proximal LC image, the head was turned in the opposite direction to the eye being imaged, and the medial part of the upper eyelid was everted to expose the LC. To obtain a lower LC image, the lower eyelid was everted just below the punctum. Using "angle mode", the scan line was placed parallel on the long axis of the LC. The inlet LC width (LCW) was measured. Artificial tears (AT) were instilled, and LCW was compared before and after AT instillation. Additionally, the return time to the initial LCW inlet width was recorded.

RESULTS

Before AT instillation, there was a significant difference between the mean upper and lower LCW (91.8 ± 3.2 µm and 110.1 ± 8.4 µm, respectively). After AT instillation, the mean upper and lower LCW were 236.9 ± 27.7 µm and 238.4 ± 30.4 µm, respectively. Significant differences in the LCW before and after AT instillation in both the upper and lower LCWs were observed. The mean return time of the upper and lower LCW to their initial widths after AT instillation was within 4 min.

CONCLUSIONS

Spectral-domain optical coherence tomography was an effective method for providing high-resolution images of the upper and lower proximal LC. This method enables observation of LC changes after instillation of eyedrops in veterinary clinical practice.

[iOCT in clinical use : Correlation of intraoperative morphology and postoperative visual outcome in patients with full thickness macular hole]

Hintergrund

Die Beurteilung der intraoperativen Veränderung der Netzhautmorphologie, insbesondere des vitreoretinalen Überganges, ist mithilfe der intraoperativen optischen Kohärenztomografie (iOCT) möglich geworden.

Ziel der Arbeit

Um die Bedeutung der intraoperativen Morphologie beim durchgreifenden Makulaforamen (MF) für das postoperative funktionelle Ergebnis zu evaluieren, wurde eine retrospektive, klinische Beobachtungsstudie durchgeführt.

Material und Methoden

Die Netzhautmorphologie wurde in 32 Augen von 32 konsekutiven Patienten mit durchgreifendem Makulaforamen mittels iOCT zu verschiedenen Zeitpunkten während der Operation beobachtet. Die Veränderungen wurden anschließend mit dem postoperativen funktionellen Ergebnis korreliert.

Ergebnisse

Nach Induktion der hinteren Glaskörperabhebung (HGA) reduzierte sich der Makulaforamen-Index (MHI) um −0,05 (p = 0,01), die basale Foramenbreite (FB) stieg um +99,4 μm (SD = 197,8 μm; p = 0,04). Die Verschlussrate betrug 100 % zum Zeitpunkt der ersten postoperativen Vorstellung nach im Mittel 73 Tagen, der postoperative Visus verbesserte sich signifikant (p < 0,05).

Es zeigte sich eine signifikant positive Korrelation von intraoperativer Morphologie und postoperativem Ergebnis zwischen einem niedrigen MHI und einem besseren postoperativen Visus (SKK = 0,50; p = 0,02), zwischen einer großen FB und einem besseren postoperativen Visus (SKK = 0,43; p = 0,05) sowie zwischen einer breiten Apertur nach HGA und einem größeren Visusanstieg postoperativ (SKK = 0,44; p = 0,03).

Diskussion

Wir konnten eine Abflachung sowie eine Verbreiterung des MF durch Lösen der vitreoretinalen Zugkräfte beobachten. Aufgrund des Zusammenhangs zwischen einer großen intraoperativen FB mit einem besseren postoperativen Visus scheint die intraoperative Relaxierung der Netzhaut bedeutsam.

PRE-RETINOPATHY OF TYPE 1 DIABETES IN THE CONTEXT OF FUNCTIONAL, STRUCTURAL AND MICROCIRCULATORY CHANGES IN THE MACULAR AREA

AIM

The authors assessed the development of intraocular changes in type 1 diabetes (T1DM) from the onset of the disease leading to diabetic retinopathy (DR). The quote: &#8220;There must be an intermediate stage between the physiological intraocular finding and the diabetic retinopathy itself &#8220;, (prof. Jan Vav&#345;inec).

METHODS

A two-year study (2018 and 2019) was conducted at the Department of Ophthalmology of the Teaching Hospital Kralovske Vinohrady in Prague (Czech Republic). There were 54 patients aged 17-42 years, the detection of T1DM ranged between the 1st and 14th year of life, with a duration of 12-35 years. Individual patients were always examined simultaneously by three methods: CS (contrast sensitivity), SD-OCT (spectral domain optical coherence tomography) and OCT-A (optical coherence tomography-angiography). We examined 106 eyes once and in a comprehensive manner.

RESULTS

We have shown that there is an intermediate stage between the physiological finding on the retina and DR, so-called diabetic pre-retinopathy (DpR). Subsequent redistribution of the observed into two DpR subgroups was derived from the size of the FAZ, either with its smaller area or with a larger area determining the microvascularity of the central area of the retina. The results of both other methods were assigned to these values. For SD-OCT, the depth of the fovea (the difference between the central retinal thickness and the total average retinal thickness) was determined, which was affected by the increased the macular cubature. In all patients it was on average 10.3 &#956;m3. The retina in the central area was significantly strengthened compared to the healthy population at the level of significance p 0,001. We divided the actual DpR into an image: DpR1 in 26.5 % of eyes - condition with an average shallower fovea only by 21.5 &#956;m below the level of the surrounding retina and an average narrower FAZ: 0.165 mm2 and with a more significant decrease in CS; DpR2 in 40.5 % of eyes - condition with average deeper fovea by 42 &#956;m, i.e., more significantly and average larger FAZ: 0.325 mm2 with lower decrease of CS. At the same time, other changes in microvascularity were noted, such as disorders in the sense of non-perfusion in the central part of the retina of various degrees. This finding differed significantly from changes in already established (non-proliferative) NPDR in 36 % of eyes, when a significant decrease in CS with normal visual acuity was found 4/4 ETDRS. Statistical differences in CS between DpR1 and DpR2 and NPDR were determined - always p 0.001. The average depth of the fovea was NPDR: 29.5 &#956;m. NPDR had the largest average FAZ: 0.56 mm2. Also significant were the most significant changes in non-perfusion and especially the presence of microaneurysms.

CONCLUSIONS

These three non - invasive methods helped to monitor the dynamics of the development of ocular changes in T1DM of better quality than the determination of visual acuity and ophthalmoscopic examination. Increased retinal volume induced hypoxia of visual cells with subsequent dual autoregulatory mechanism conditioning two types of diabetic pre-retinopathy before the onset of DR.

Prognostic biomarkers of chronic diabetic macular edema treated with a fiuocinolone acetonide intravitreal implant

Background

This study aimed to investigate retinal imaging biomarkers, such as disorganization of the retinal inner layers (DRIL) and/or ellipsoid zone (EZ) disruption by spectral domain optical coherence tomography (SD-OCT), and functional outcomes in eyes treated with 0.2 µg/day of a fluocinolone acetonide intravitreal implant (FAc) after an insufficient response to previous treatments.

Methods

This was a retrospective comparative study of 18 eyes (15 patients) with persistent and/or recurrent diabetic macular edema (DME) treated with FAc. Eyes were divided according to the number of prior intravitreal treatments: group 1 (n = 8) with ≤ 6 injections (early switch) and group 2 (n = 10) with > 6 injections (late switch). Outcomes included percentage of eyes with DRIL and/or EZ disruption at baseline and analysis of the best corrected visual acuity (BCVA) using ETDRS letters, central macular thickness (CMT), DRIL, and EZ disruption at the last observation.

Results

Group 2 revealed a significantly higher percentage of DRIL and/or EZ disruption than group 1 (P < 0.05). At the last observation, group 1 revealed a higher percentage of eyes achieving vision stability/ improvement, gaining ≥ 15 letters, and achieving ≥70 letters (P > 0.05 for all comparisons). The mean BCVA gain was 8.8 and 0.7 letters for groups 1 and 2 (P = 0.397). Both groups revealed a significant mean CMT reduction (> 20% reduction from the baseline value), without a significant statistical difference between them (P = 0.749). After treatment, most eyes from both groups showed resolution of DRIL and EZ disruption.

Conclusions

Patients with DME presenting with a lower percentage of DRIL and/or EZ disruption at baseline had better functional outcomes, supporting the possible benefit of an early switch to FAc after insufficient response to previous treatments. Future randomized studies with a larger patient cohort are warranted to confirm our conclusions.

Early identification of keratoconus using pachymetric indexes obtained with spectral domain optical coherence tomography

Purpose

To evaluate the diagnostic ability of pachymetric indexes obtained with Spectral Domain Optical Coherence Tomography (SD-OCT) for early detection of keratoconus (Kc).

Methods

64 patients with Kc in at least one eye (95 eyes, 46 men and 18 women, average age 27.84 ±13.50), 59 healthy control subjects (100 eyes, 28 men and 31 women, average age 27.15 ±16.14). All patients underwent detailed clinical examination, topography and anterior segment OCT. 37 subjects (37 eyes, 27 men and 10 women, average age 24.23 ± 14.24) having one eye with manifest Kc and the fellow eye without clinical signs of Kc were identified. We studied two groups of pachymetric indexes: C1-C2, M1-M2, pCLMI, Pmin-P2 (Group 1 indexes) and PPD, PSD, PSSD and PASD (Group 2 indexes). A ROC (Receiver Operating Characteristic) curve was developed to compare the diagnostic accuracy, relative sensitivity and specificity for each index.

Results

In manifest keratoconus, C1-C2, M1-M2, and pCLMI are significantly higher compared to the control group (P<0.0001); for suspect keratoconus, all Group 1 indexes are significantly higher compared to healthy subjects (P<0.0001) excluding M1-M2 obtained using a constant area circle (P = 0.02). Furthermore, for manifest and suspect keratoconus, PPD, PSD, PSSD and PASD are significantly higher compared to the control group (P <0.0001).

Conclusion

The studied pachymetric indexes in patients with Kc have high diagnostic accuracy and are statistically significant when compared with healthy subjects (p<0.0001) and can provide a useful tool for keratoconus screening.

Reproducibility of SD-OCT inner macular layer thickness measurements in children with primary congenital glaucoma

PURPOSE

To examine the reproducibility of spectral domain optical coherence tomography (SD-OCT) segmented ganglion cell complex and circumpapillary retinal nerve fiber layer (cpRNFL) measurements in children with primary congenital glaucoma (PCG) in comparison with healthy children.

METHODS

12 children with PCG (G1) and 24 healthy children (G2) were recruited. The following SD-OCT measurements (Spectralis, Heidelberg Engineering) were made in one eye per child: total macular thickness (MT), thicknesses in several subfields and volumes of the three inner macular layers, macular retinal nerve fiber layer (mRNFL), ganglion cell layer (GCL), and inner plexiform layer (IPL) and cpRNFL thickness. In a single day, an expert operator obtained 3 circumpapillary and 3 macular measurements in each participant to determine intraoperator variability. Intraoperator repeatability was defined by the coefficient of variation (CoV) and intraclass correlation (ICC).

RESULTS

ICC was excellent in both groups for cpRNFL measurements (G1 ICC=0.950 and G2 ICC=0.995) and for MT was excellent in G1 (ICC=0.957) and moderate in G2 (ICC=552). For the inner macular layer measurements, all ICCs were better in PCG group (mRNFL-ICC: 0.915 vs. 0.765; ICC-GCL: 0.584 vs. 0.263 and ICC-IPL: 0.979 vs. 0.742; G1 and G2 respectively). Greater CoV were recorded for macular measurements (from 0.71% to 9.82%) compared to cpRNFL measurements (from 0.52% to 1.50%).

CONCLUSION

In children with PCG, Spectralis SD-OCT showed excellent intrasession repeatability for cpRNFL, MT, mRNFL and IPL measurements and moderated for GCL measurements. For all macular measurements, ICC were higher in children with PCG than healthy children.

Thinning of the inner and outer retinal layers, including the ganglion cell layer and photoreceptor layers, in obstructive sleep apnea and hypopnea syndrome unrelated to the disease severity

PURPOSE

The aim of this study was to analyze the segmented layers of the macula in patients with obstructive sleep apnea and hypopnea syndrome (OSAS) using spectral domain optical coherence tomography (SD-OCT).

MATERIAL AND METHODS

This single-center, cross-sectional study included 31 OSAS patients and 31 age- and gender-matched control subjects. SD-OCT and overnight polysomnography were performed on all participants. The OSAS patients were categorized according to disease severity (mild, moderate, severe). The groups were compared in respect of each segmented macular layer through the use of segmentation software on SD-OCT. Total retinal thickness (RT), peripapillary retina nerve fiber layer (pRNFL) thickness, central corneal thickness (CCT) and intraocular pressure (IOP) values were also compared between the groups.

RESULTS

Mean CCT (p:0.015) and nasal pRNFL values (p:0.042) were lower and mean IOP was higher (p:0.018) in OSAS patients than in the control group. The statistical analysis revealed significantly thinner total RT, inner retinal layers (IRL), outer retinal layers (ORL), photoreceptor layers (PRL) and ganglion cell layer (GCL) thicknesses in the OSAS groups compared to healthy subjects. No significant differences were found between the three OSAS subgroups in all segmented macular layers and pRNFL measurements.

CONCLUSION

The results of this study showed relatively thinner nasal pRNFL, total RT, IRL, ORL, PRL and GCL layers in OSAS patients compared to healthy subjects. Moreover, this thinning of the segmented layers was unrelated to disease severity.

Short-term effect of non-preserved cationic oil-in-water ophthalmic emulsion on tear meniscus parameters of healthy individuals in a prospective, controlled pilot study

Background

This study investigated the effect of instilling a single drop of non-preserved cationic oil-in- water ophthalmic emulsion (Cationorm®) on the lower (LTM) and upper tear meniscus (UTM) parameters of normal eyes.

Methods

In this prospective, single-center, non-randomized, controlled pilot study, optical coherence tomography was used to estimate the UTM and LTM height, depth, and cross-sectional area in participants without a history of dry eye disease. In the right eye (study eye), we instilled one drop of Cationorm® in the lower conjunctival sac. Scans of the tear menisci were acquired at baseline, before the instillation, and at 5, 15, and 30 min thereafter. Control scans of the left eye (control eye) were obtained at the same timepoints. The tear meniscus parameters of the study eye were compared with the control eye at each timepoint.

Results

Twenty subjects (11 male and 9 female; mean [standard deviation] of age: 37.8 [10.9] years) were included in the study. Compared to the control eye, instillation of a single drop of Cationorm® resulted in significantly higher LTM parameter values and a higher UTM cross-sectional area up to 30 min after instillation (all P < 0.05). The UTM height and depth were significantly greater in the study eye than in the control eye up to 5 min (P < 0.001 and 0.007, respectively) and 15-min (P = 0.045, and 0.002, respectively) after Cationorm® instillation. In the study eye, Cationorm® resulted in a significant increase in LTM parameter values up to 30 min post-instillation (all P < 0.001). The UTM height was significantly greater up to 15 min post-instillation than at baseline. The UTM depth and area increased significantly from baseline to 5 min after instillation (P = 0.043, and 0.002, respectively).

Conclusions

Cationorm® seems to have a prolonged residence time on the ocular surface of healthy subjects as indicated by LTM parameters and to a lesser extent by UTM parameters.

Comparison of spectral domain optical coherence tomography parameters between disc suspects and "pre-perimetric" glaucomatous discs classified on disc photo

Purpose:

The aim of this study was to compare SD-OCT parameters between disc suspects and “pre-perimetric” glaucomatous discs classified on disc photos.

Methods:

Disc photos of suspicious discs with normal Humphrey visual fields (HVF) were graded as normal or pre-perimetric glaucomatous based on the consensus of three masked glaucoma specialists. RNFL and GCL-IPL maps of SD-OCT (Cirrus OCT) of these eyes were studied. Quantitative RNFL parameters were compared. Both groups were also compared with respect to parameters being classified as abnormal (at the 1% level), and the pattern of GCL-IPL and NFL maps were assessed qualitatively and classified as normal or pre-perimetric glaucomatous by a masked glaucoma specialist.

Results:

The average and inferior RNFL thicknesses were decreased in pre-perimetric glaucomatous eyes compared to normal eyes (p 0.01) The average, minimal, inferotemporal and inferior sector GCL-IPL thicknesses were decreased in pre-perimetric glaucomatous eyes (all P < 0.002) The highest AUC was for the inferior RNFL thickness (0.771) followed by average RNFL thickness (0.757) The sensitivity and specificity for any one abnormal RNFL parameter was 71.9% and 59.7%, for GCL-IPL parameters was 70% and 69.1% The positive (PLR) and negative likelihood ratios (NLR) were 1.78 and 0.47 for RNFL and 2.26 and 0.43 for GCL-IPL parameters. For the qualitative assessment of RNFL and GCL-IPL maps, the sensitivity, specificity, PLR and NLR were 75%, 77.2%, 3.29, and 0.32, respectively.

Conclusion:

Pre-perimetric disc suspects had greater OCT changes compared to normal disc suspects. Qualitative assessment of RNFL and GCL-IPL maps had the highest discriminatory ability.

Multimodal imaging interpreted by graders to detect re-activation of diabetic eye disease in previously treated patients: the EMERALD diagnostic accuracy study

BACKGROUND

Owing to the increasing prevalence of diabetes, the workload related to diabetic macular oedema and proliferative diabetic retinopathy is rising, making it difficult for hospital eye services to meet demands.

OBJECTIVE

The objective was to evaluate the diagnostic performance, cost-effectiveness and acceptability of a new pathway using multimodal imaging interpreted by ophthalmic graders to detect reactivation of diabetic macular oedema/proliferative diabetic retinopathy in previously treated patients.

DESIGN

This was a prospective, case-referent, cross-sectional diagnostic study.

SETTING

The setting was ophthalmic clinics in 13 NHS hospitals.

PARTICIPANTS

Adults with type 1 or type 2 diabetes with previously successfully treated diabetic macular oedema/proliferative diabetic retinopathy in one/both eyes in whom, at the time of enrolment, diabetic macular oedema/proliferative diabetic retinopathy could be active or inactive.

METHODS

For the ophthalmic grader pathway, review of the spectral domain optical coherence tomography scans to detect diabetic macular oedema, and seven-field Early Treatment Diabetic Retinopathy Study/ultra-wide field fundus images to detect proliferative diabetic retinopathy, by trained ophthalmic graders. For the current standard care pathway (reference standard), ophthalmologists examined patients face to face by slit-lamp biomicroscopy for proliferative diabetic retinopathy and, in addition, spectral domain optical coherence tomography imaging for diabetic macular oedema.

OUTCOME MEASURES

The primary outcome measure was sensitivity of the ophthalmic grader pathway to detect active diabetic macular oedema/proliferative diabetic retinopathy. The secondary outcomes were specificity, agreement between pathways, cost-consequences, acceptability and the proportion of patients requiring subsequent ophthalmologist assessment, unable to undergo imaging and with inadequate quality images/indeterminate findings. It was assumed for the main analysis that all patients in whom graders diagnosed active disease or were 'unsure' or images were 'ungradable' required examination by an ophthalmologist.

RESULTS

Eligible participants with active and inactive diabetic macular oedema (152 and 120 participants, respectively) and active and inactive proliferative diabetic retinopathy (111 and 170 participants, respectively) were recruited. Under the main analysis, graders had a sensitivity of 97% (142/147) (95% confidence interval 92% to 99%) and specificity of 31% (35/113) (95% confidence interval 23% to 40%) to detect diabetic macular oedema. For proliferative diabetic retinopathy, graders had a similar sensitivity and specificity using seven-field Early Treatment Diabetic Retinopathy Study [sensitivity 85% (87/102), 95% confidence interval 77% to 91%; specificity 48% (77/160), 95% confidence interval 41% to 56%] or ultra-wide field imaging [sensitivity 83% (87/105), 95% confidence interval 75% to 89%; specificity 54% (86/160), 95% confidence interval 46% to 61%]. Participants attending focus groups expressed preference for face-to-face evaluations by ophthalmologists. In the ophthalmologists' absence, patients voiced the need for immediate feedback following grader's assessments, maintaining periodic evaluations by ophthalmologists. Graders and ophthalmologists were supportive of the new pathway. When compared with the reference standard (current standard pathway), the new grader pathway could save £1390 per 100 patients in the review of people with diabetic macular oedema and, depending on the imaging modality used, between £461 and £1189 per 100 patients in the review of people with proliferative diabetic retinopathy.

CONCLUSIONS

For people with diabetic macular oedema, the ophthalmic grader pathway appears safe and cost saving. The sensitivity of the new pathway to detect active proliferative diabetic retinopathy was lower, but may still be considered acceptable for patients with proliferative diabetic retinopathy previously treated with laser. Suggestions from focus group discussions should be taken into consideration if the new pathway is introduced to ensure its acceptability to users.

LIMITATIONS

Lack of fundus fluorescein angiography to confirm diagnosis of active proliferative diabetic retinopathy.

FUTURE WORK

Could refinement of the new pathway increase its sensitivity to detect proliferative diabetic retinopathy? Could artificial intelligence be used for automated reading of images in this previously treated population?

TRIAL REGISTRATION

Current Controlled Trials ISRCTN10856638 and ClinicalTrials.gov NCT03490318.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology AssessmentVol. 25, No. 32. See the NIHR Journals Library website for further project information.

The impact of central foveal thickness and integrity of the outer retinal layers in the visual outcome of uveitic macular edema

Background

To analyze the relationship between the central foveal thickness (CFT) and the integrity of the ellipsoid portion of inner segments (EPIS) and interdigitating zone (IZ) retinal layers in the visual outcome of uveitic macular edema (UME).

Methods

Prospective, observational, and cross-sectional study of eyes with UME. Spectral-domain optical coherence tomography (SD-OCT) macular morphological pattern, CFT, and integrity of the outer retinal layers were analyzed. We arranged the data by EPIS or IZ integrity and contrasted it with student t-test (quantitative variables) and Fisher exact test or χ² distribution (categorical variables) to evaluate visual impairment and retinal measures. Receiver operator curve (ROC) estimation and logistic regression (probit) assessed if the sample´s variance could be associated with IZ or EPIS integrity.

Results

We included 145 SD-OCT macular scans from 45 patients at different stages of UME. Cystoid macular edema (CME) increased the risk of severe (P ≤ 0.0162) and moderate visual loss (P ≤ 0.0032). The highest CFT values occurred in patients with moderate (478.11 ± 167.62 μm) and severe (449.4 ± 224.86 μm) visual loss. Of all morphological patterns of macular edema, only CME showed a statistically significant relationship with severe visual impairment (44.92%, p = 0.0035, OR 4.29 [1.62–11.4]). Likewise, an increased probability of severe visual loss correlated negatively with both, IZ (37.93%, P ≤ 0.001, OR 10.02) and EPIS (38.98%, P ≤ 0.001, OR 13.1) disruption. A CFT > 337 μm showed a higher probability of IZ (AUROC = 0.7341, SEN 77.59%, ESP 65.52) and EPIS (AUROC = 0.7489, SEN 76.37%, ESP 65.12%) loss of integrity. Moreover, when BCVA reached 0.44 LogMAR (≤ 20/50 Snellen eq.), it was more likely to have IZ (AUROC = 0.8706, ESP 88.51%, SEN 77.59%) and EPIS (AUROC = 0.8898, ESP 88.3%, SEN 76.27) disruption.

Conclusions

Significantly increased CFT has a higher probability for EPIS and IZ disruption, which significantly increases the risk for irreversible visual loss in eyes with UME. Evaluating these layers’ integrity by optical coherence tomography helps predict the visual outcome and make the right therapeutic decisions.

Trial registration The study was registered on April 13, 2020, at the Instituto Tecnologico y de Estudios Superiores de Monterrey Research Committee (License No. COFEPRIS 20 CI 19 039 002), project registration No. P000338-CAVICaREMU-CI-CR002, and the Ethics Committee (License No. CONBIOETICA 19 CEI 011-2016-10-17), project registration No. P000338-CAVICaREMU-CEIC-CR002

[Examination of patients with glaucoma during the COVID-19 pandemic]

PURPOSE

To evaluate the efficacy of the optimal examination technique for patients with glaucoma during the COVID-19 pandemic that includes one of the safest methods of tonometry [transpalpebral tonometry (TPT), contour dynamic tonometry (CDT) and Icare rebound tonometry (RBT)] in combination with spectral domain optical coherence tomography (SD-OCT) and optical coherence tomography angiography (OCTA).

MATERIAL AND METHODS

The study included 65 patients with primary open-angle glaucoma (POAG) who sought medical aid at the Ophthalmological Center of FMBA during the COVID-19 pandemic; they were examined using three tonometry methods: RBT, TPT and CDT. All patients underwent central corneal thickness measurement, perimetry, OCT and OCTA with assessment of vessel density (VD) of the superficial plexus in the macula (whole image macula) and peripapillary retina (PPR).

RESULTS

High correlation was found between the results obtained with RBT, TPT and CDT. None of the methods showed a correlation between IOP and corneal thickness. The correlations between IOP and OCTA parameters were obtained: IOP_TPT and VD_PPR in the inferior temporal sector (r= -0.386, p=0.027), IOP_RBT and VD whole image macula (r= -0.69, p=0.019), and in the macula inferior hemisphere (r= -0.75, p=0.008), as well as between the ocular pulse amplitude (OPA) and VD in the macular inferior hemisphere (r=0.380, p=0.039). The OCTA parameters had a moderate, but significant correlation with the perimetric indices.

CONCLUSIONS

Tonometry methods (TPB, CDT and RBT) exhibit high correlation with each other and no correlation with corneal thickness. IOP parameters measured by different methods, especially using the Icare tonometer, correlate with OCTA parameters, and the latter - with perimetric indices. The combination of these tonometry methods with SD-OCT and OCTA is optimal for examining patients during the pandemic.

[Large macular hole-Always a poor prognosis?]

Hintergrund

Alter, präoperativer Visus und Makulaforamengröße gelten als prognostische Marker für das postoperative Ergebnis bei Patienten mit durchgreifendem Makulaforamen (MF).

Ziel der Arbeit

Um den postoperativen Verlauf nach i‑ILM Peeling (inverted-Flap ILM-Peeling) mit konventionellem ILM-Peeling (k-ILM) zu vergleichen, wurde eine retrospektive Beobachtungsstudie durchgeführt. Patienten mit i‑ILM Peeling hatten dabei präoperativ ein statistisch signifikant größeres Makulaforamen.

Material und Methoden

Es wurden 45 konsekutive Patienten mit durchgreifendem Makulaforamen (MF) in 2 Gruppen (i-ILM vs. k‑ILM) eingeteilt und auf Unterschiede im postoperativen Visus (BCVA) und der Netzhautmorphologie hin untersucht. Die Integrität der äußeren Netzhautschichten, äußere limitierende Membran (ELM), ellipsoide Zone (EZ) und äußere Photorezeptoraußensegmente (OS), wurde postoperativ mittels SD-OCT (Spectral-Domain-OCT) analysiert.

Ergebnisse

Die präoperative Apertur in der i‑ILM Gruppe war signifikant größer (i-ILM = 408,4 µm, SD = 157,5 µm; k‑ILM = 287,4 µm, SD = 104,9 µm; p = 0,01). Der Ausgangsvisus sowie der postoperative Visus nach 1 Monat waren in der Gruppe mit k‑ILM-Peeling signifikant besser (p = 0,03 und p = 0,001). Der postoperative Visus nach mindestens 6 Monaten zeigte keinen signifikanten Unterschied zwischen den beiden Gruppen (p = 0,24). Die ELM zeigte als erste der äußeren Netzhautschichten eine Re-Integrität in beiden Gruppen.

Schlussfolgerung

Mithilfe der i‑ILM-Peeling-Technik erschien es in dieser konsekutiven Serie möglich zu sein, für Patienten mit großem durchgreifendem MF ein ähnliches postoperatives Visusergebnis zur erreichen wie für mittels k‑ILM-Peeling-Technik operierte Patienten mit kleinerem durchgreifendem MF.

RPE layer detection and baseline estimation using statistical methods and randomization for classification of AMD from retinal OCT

BACKGROUND AND OBJECTIVE

Age-related macular degeneration (AMD) is a condition of the eye that affects the aged people. Optical coherence tomography (OCT) is a diagnostic tool capable of analyzing and identifying the disease affected retinal layers with high resolution. The objective of this work is to extract the retinal pigment epithelium (RPE) layer and the baseline (natural eye curvature, particular to every patient) from retinal spectral-domain OCT (SD-OCT) images. It uses them to find the height of drusen (abnormalities) in the RPE layer and classify it as AMD or normal.

METHODS

In the proposed work, the contrast enhancement based adaptive denoising technique is used for speckle elimination. Pixel grouping and iterative elimination based on the knowledge of typical layer intensities and positions are used to obtain the RPE layer. Using this estimate, randomization techniques are employed, followed by polynomial fitting and drusen removal to arrive at a baseline estimate. The classification is based on the drusen height obtained by taking the difference between the RPE and baseline levels. We have used a patient, wise classification approach where a patient is classified diseased if more than a threshold number of patient images have drusen of more than a certain height. Since all slices of an affected patient will not show drusen, we are justified in adopting this technique.

RESULTS

The proposed method is tested on a public data set of 2130 images/slices, which belonged to 30 patient volumes (15 AMD and 15 Normal) and achieved an overall accuracy of 96.66%, with no false positives. In comparison with existing works, the proposed method achieved higher overall accuracy and a better baseline estimate.

CONCLUSIONS

The proposed work focuses on AMD/normal classification using a statistical approach. It does not require any training. The proposed method modifies the motion restoration paradigm to obtain an application-specific denoising algorithm. The existing RPE detection algorithm is modified significantly to make it robust and applicable even to images where the RPE is not very evident/there is a significant amount of perforations (drusen). The baseline estimation algorithm employs a powerful combination of randomization, iterative polynomial fitting, and pixel elimination in contrast to mere fitting techniques. The main highlight of this work is, it achieved an exact estimation of the baseline in the retinal image compared to the existing methods.

Imaging in inherited retinal disorders

Inherited retinal diseases, which results from mutations in over 260 identified genes, affect more than 2 million people globally. The diseases mostly cause severe vision loss in young working population and have severe impact on social economic status of the population. Advances in retinal imaging techniques along with developments in gene identification and cell biology techniques have yielded to a better understanding of the genetic and biochemical mechanisms causing these diseases. Retinal imaging along with through ophthalmological examination is essential to make an accurate diagnosis, to decrease the burden of unneccessary anciliary tests and to select the potential patients that can get benefit from the gene treatment. The purpose of the review is to yield an update on inherited retinal diseases by highlighting microstructural changes in retina and to summarize the retinal changes detected by currently available multimodal imaging techniques.

Optical Coherence Tomography Angiography Findings After Intravitreal Ranibizumab in Patients With Coats Disease

The aim of this retrospective study was to describe the vascular features in eyes with Coats disease, using optical coherence tomography angiography (OCTA), at baseline and after 3 monthly intravitreal injections of ranibizumab. Fifteen eyes of 15 consecutive patients affected by Coats' disease were recruited in this study. All patients underwent the best-corrected visual acuity (BCVA) evaluation, fundus examination, fluorescein angiography (FA), indocyanine green angiography (ICGA), multicolor imaging, structural Spectral Domain (SD)-OCT and OCTA at baseline and 1 month after the third monthly ranibizumab injection (loading phase). Fifteen patients completed the study, of whom nine were males and six females. Mean age was 20.4 ± 2 years. BCVA was 0.46 ± 0.11 logMar and 0.47 ± 0.12 logMar at baseline and after treatment, respectively (p = 0.164). SD-OCT revealed no significant decrease in central macular thickness (486.33 μm ± 93.37 at baseline vs. 483.4 μm ± 80.97 after treatment; p = 0.915). The subretinal exudates persisted in macular region after intravitreal injections. OCTA showed a general vascular rarefaction in superficial capillary plexus (SCP), deep capillary plexus (DCP), and choriocapillary (CC) that did not change after loading phase. This study showed no functional and vascular improvement following 3 monthly ranibizumab injections. OCTA, non-invasive technique, could be useful during follow up of these patients and provide a better understand of pathogenesis of this disorder.

Spectral Domain - Optical Coherence Tomography findings in Triple-A Syndrome - A case series from Pakistan

Triple A Syndrome is an autosomal recessive entity involving multiple systems usually characterized by adrenal insufficiency, alacrimia and achalasia. The disease features include variable degrees of neurological and neuro-ophthalmic manifestations. Protein ALADIN encoded by the AAAS gene is found to be defective in Triple A Syndrome. Here we discuss a case series of five patients diagnosed as Triple A Syndrome. Clinically there was variable degree of optic atrophy in all the cases, which was further confirmed with spectral domain Optical Coherence Tomography The aim of this study was to publish the OCT based ONFL graphs of these unique cases, so that being an ophthalmologist we can take a multidisciplinary approach and decisions accordingly.

An integrated time adaptive geographic atrophy prediction model for SD-OCT images

The automated prediction of geographic atrophy (GA) lesion growth can help ophthalmologists understand how the GA progresses, and assess the efficiency of current treatment and the prognosis of the disease. We developed an integrated time adaptive prediction model for identifying the location of future GA growth. The proposed model was comprised of bi-directional long short-term memory (BiLSTM) network-based prediction module and convolutional neural network (CNN)-based refinement module. Considering the discontinuity of time intervals among sequential follow-up visits, we integrated time factors into BiLSTM-based prediction module to control the time attribute expediently. Then, the results from prediction module were refined by a CNN-based strategy to obtain the final locations of future GA growth. The 10 scenarios were designed to evaluate the prediction accuracy of our proposed model. The 1-6th scenarios demonstrated the importance of the prior information similarity, the 7-8th scenarios verified the effect of time factors and refinement methods respectively and the 9th scenario compared the prediction results between those using a single follow-up visit for training and using 2 sequential follow-up visits for training. The 10th scenario showed the model generalization performance across regions. The average dice indexes (DI) of the predicted GA regions in the 1-6th scenarios are 0.86, 0.89, 0.89, 0.92 and 0.88, 0.90, respectively. By integrating time factors to the BiLSTM models, the prediction accuracy was improved by almost 10%. The CNN-based refinement strategy can remove the wrong GA regions effectively to preserve the actual GA regions and improve the prediction accuracy further. The prediction results based on 2 sequential follow-up visits showed higher correlations than that based on single follow-up visit. The proposed model presented a good generalization performance while training patients and testing patients were from different regions. Experimental results demonstrated the importance of prior information to the prediction accuracy. We demonstrate the feasibility of creating a model for disease prediction.

Influence of Perfluorocarbon Liquids on Peripapillary Retinal Nerve Fiber-Layer Thickness Following Pars Plana Vitrectomy with Silicone Oil-Based Endotamponade

Background

Inner retina–layer modifications after pars plana vitrectomy (PPV) can be objectively assessed through spectral domain optical coherence tomography (SD-OCT).

Methods

This study explored prospectively changes in retinal nerve-fiber layer (RNFL) thickness with SD-OCT in eyes undergoing PPV with silicone oil–based tamponade with and without use of perfluorocarbon liquids (PFCLs) during the early postoperative phase (up to 3 months) at the Research Institute of Ophthalmology, Egypt.

Results

Thirty patients were recruited who underwent PPV and silicone oil–based tamponade for either retinal detachment or diabetic retinopathy between April 2019 and September 2019. Mean RNFL thickness showed no significant change during follow-up at the first week (102.90±30.68 mm), 1 month (107.30±32.27), or three months (105.90±36.68; p=0.46, 0.68). There were significant correlations noticed between RNFL thinning and axial length of eyes, intraocular pressure, and use of PFCLs during the follow-up period.

Conclusion

The RNFL tends to change postvitrectomy, but not significantly. Careful examination and consistent follow-up is required for postvitrectomy patients with larger axial length and intraoperative PFCL use.

The role of OCT angiography in a rare case of malignant trasformation of an optic disc melanocytoma

The melanocytoma is a benign, highly pigmented tumor, localized on or adjacent to the optic disc. Its malignant trasformation represents a rare event. We describe a case of a 43-years old woman returned to our observation 29 years later with a malignant melanoma from an optic disc melanocytoma evaluated by Optical Coherence Tomography Angiography (OCTA). OCTA is a valid, non-invasive, dyeless and reliable method that could improve the diagnosis of this rare case of malignant trasformation of an optic disc melanocytoma.

Prevalence of epiretinal membranes in the ageing population using retinal colour images and SD-OCT: the Alienor Study

PURPOSE

To analyse and compare the prevalence of epiretinal membranes (ERMs) obtained using either standard retinal colour images or spectral-domain optical coherence tomography (SD-OCT) in a population-based setting of French elderly subjects.

METHODS

Six hundred twenty-four subjects of the Alienor cohort aged 75 years or older underwent both colour fundus imaging and SD-OCT examinations. The ERMs were graded from retinal images and SD-OCT macular scans in a masked fashion. On SD-OCT images, the early ERMs, mature contractile ERMs without foveal modifications and mature contractile ERMs with foveal alterations were distinguished.

RESULTS

610 (97.8%) subjects had gradable SD-OCT examinations, and 511 (81.9%) had gradable fundus images in at least one eye. According to colour photographs, 11.6% of participants had definite ERMs. From SD-OCT images, 52.8% of the subjects had early ERMs, 7.4% had mature ERMs without foveal involvement, and 9.7% had mature ERMs with foveal alterations. Regardless of the imaging method used, the ERMs were more often observed in pseudophakic eyes than in phakic eyes. Comparison of ERM assessment using fundus photographs versus SD-OCT images demonstrated that the specificity of retinal colour images was good (>89.3%), whereas the sensitivity remained low even though it increased with ERM severity on SD-OCT images.

CONCLUSIONS

Spectral-domain optical coherence tomography (SD-OCT) examinations have high feasibility in this elderly population and are much more sensitive than standard colour images for ERM assessments, especially in the early stages of the disease. Our results further highlight the need to use SD-OCT instead of colour retinal photographs for the classification of ERMs in epidemiological studies.

Retinal Vascular Features in Ocular Blunt Trauma by Optical Coherence Tomography Angiography

In this prospective study, we analysed the changes in retinal vessel density (VD) using optical coherence tomography angiography (OCTA) in patients with commotio retinae up to 6 months after blunt ocular trauma. We analysed the VD in the superficial capillary plexus (SCP), deep capillary plexus (DCP), radial peripapillary capillary (RPC) and the foveal avascular zone (FAZ) area at 48 h, and 1, 3 and 6 months after the trauma and compared results with those of healthy fellow eyes. We also evaluated the best-corrected visual acuity (BCVA) and the structural, spectral domain (SD)-OCT parameters: ganglion cell complex (GCC) and retinal nerve fibre layer (RNFL). A total of 18 eyes of 18 patients (8 males, 10 females, mean age 49.61 ± 9.2 years) and 18 healthy control eyes were evaluated. GCC and RNFL thicknesses showed a significant trend towards progressively lower values from 1 month and 3 months after the trauma, respectively, compared to healthy eyes (p < 0.005). The reduction in SD-OCT parameters reached a plateau at 6 months. Similar behaviour was found in the VD of the SCP and RPC that significantly decreased, starting from 1 and 3 months after the trauma, respectively (p < 0.001). At 6 months, the VD values were stable. The DCP presented an initial decrease of VD (p < 0.001), and after 1 month, the values statistically increased until the sixth month, reaching values similar to those of the control group. The FAZ area and BCVA did not show statistically significant changes during the follow-up. OCTA provided a detailed and quantitative analysis of early retinal vascular perfusion alterations after commotio retinae, demonstrating that the impairment of the retinal microvasculature and its progressive changes over time occurred even in the absence of compromised visual acuity.

The comparison of spectral domain optical coherence tomography and indocyanine green angiography in the diagnosis of polypoidal choroidal vasculopathy

OBJECTIVES

To evaluate the diagnostic capability of spectral domain optical coherence tomography (SD-OCT) in patients with potential diagnostic findings for polypoidal choroidal vasculopathy (PCV).

MATERIALS AND METHODS

Ninety-three eyes with potential diagnostic findings for PCV were prospectively evaluated. Patients with multiple retinal pigment epithelial detachment (RPED), sharp RPED peak, RPED notch, hyporeflective lumen representing polyps, double-layer sign and the presence of hyperreflective intraretinal hard exudate were considered as PCV in SD-OCT. The sensitivity and specificity of SD-OCT in the diagnosis of PCV were determined by comparing SD-OCT-based diagnosis with indocyanine green angiography (ICGA).

RESULTS

Sixty-nine (74.2%) of 93 eyes included in the study were confirmed with ICGA and diagnosed as PCV. The sensitivity and specificity of SD-OCT for the diagnosis of PCV were 75.3% and 75%, respectively.

CONCLUSION

The SD-OCT-based method helps clinicians to develop appropriate diagnostic and treatment strategies for patients in whom ICGA cannot be used.