Comparison of Optical Coherence Tomography Measurement Reproducibility between Children and Adults

Purpose

To compare the reproducibility of SD-OCT (spectral-domain optical coherence tomography) measurements of RNFL (retinal nerve fiber layer) and macular thickness between children and adults.

Methods

Seventy-one eyes of 71 children and 71 eyes of 71 adults were prospectively enrolled. RNFL and macular thicknesses were measured by one operator, with a brief rest between measurements. The two measurements were obtained using the eye tracking and retest function of Spectralis SD-OCT. Reproducibility was evaluated with reference to COVs (coefficients of variation) and ICCs (intraclass correlation coefficients). The ICC values of the RNFL and macular thicknesses were compared, respectively between the two groups, by Fisher’s z-test.

Results

The RNFL and macular thicknesses did not differ between the two groups. The COVs of the RNFL measurements ranged from 0.945 to 4.531% in the children group and from 0.496 to 1.391% in the adults group. In most of the RNFL sectors, the ICCs of the children group (range: 0.731–0.987) were significantly lower than those of the adults group (range: 0.986–0.993). The COVs of the macular measurements ranged from 0.496 to 1.157% in the children group and from 0.275 to 0.656% in the adults group. The ICCs (range: 0.860–0.974) in the children group, significantly lower than for the adults (range: 0.989–0.995), in all of the macular sectors.

Conclusions

The reproducibility of SD-OCT RNFL and macular measurements for children was excellent, albeit statistically lower than that for adults.     

Diagnostic Ability of Macular Ganglion Cell Inner Plexiform Layer Measurements in Glaucoma Using Swept Source and Spectral Domain Optical Coherence Tomography

PurposeTo evaluate the diagnostic ability of macular ganglion cell and inner plexiform layer measurements in glaucoma, obtained using swept source (SS) and spectral domain (SD) optical coherence tomography (OCT) and to compare to circumpapillary retinal nerve fiber layer (cpRNFL) thickness measurements.MethodsThe study included 106 glaucomatous eyes of 80 subjects and 41 eyes of 22 healthy subjects from the Diagnostic Innovations in Glaucoma Study. Macular ganglion cell and inner plexiform layer (mGCIPL), macular ganglion cell complex (mGCC) and cpRNFL thickness were assessed using SS-OCT and SD-OCT, and area under the receiver operating characteristic curves (AUCs) were calculated to determine ability to differentiate glaucomatous and healthy eyes and between early glaucomatous and healthy eyes.ResultsMean (± standard deviation) mGCIPL and mGCC thickness were thinner in both healthy and glaucomatous eyes using SS-OCT compared to using SD-OCT. Fixed and proportional biases were detected between SS-OCT and SD-OCT measures. Diagnostic accuracy (AUCs) for differentiating between healthy and glaucomatous eyes for average and sectoral mGCIPL was similar in SS-OCT (0.65 to 0.81) and SD-OCT (0.63 to 0.83). AUCs for average cpRNFL acquired using SS-OCT and SD-OCT tended to be higher (0.83 and 0.85, respectively) than for average mGCC (0.82 and 0.78, respectively), and mGCIPL (0.73 and 0.75, respectively) but these differences did not consistently reach statistical significance. Minimum SD-OCT mGCIPL and mGCC thickness (unavailable in SS-OCT) had the highest AUC (0.86) among macular measurements.ConclusionAssessment of mGCIPL thickness using SS-OCT or SD-OCT is useful for detecting glaucomatous damage, but measurements are not interchangeable for patient management decisions. Diagnostic accuracies of mGCIPL and mGCC from both SS-OCT and SD-OCT were similar to that of cpRNFL for glaucoma detection.     

Retinal Thickness Measurement Obtained with Spectral Domain Optical Coherence Tomography Assisted Optical Biopsy Accurately Correlates with Ex Vivo Histology

Background

This study determines ‘correlation constants’ between the gold standard histological measurement of retinal thickness and the newer spectral-domain optical coherence tomography (SD-OCT) technology in adult C57BL/6 mice.

Methods

Forty-eight eyes from adult mice underwent SD-OCT imaging and then were histologically prepared for frozen sectioning with H&E staining. Retinal thickness was measured via 10x light microscopy. SD-OCT images and histological sections were standardized to three anatomical sites relative to the optic nerve head (ONH) location. The ratios between SD-OCT to histological thickness for total retinal thickness (TRT) and six sublayers were defined as ‘correlation constants’.

Results

Mean (± SE) TRT for SD-OCT and histological sections was 210.95 µm (±1.09) and 219.58 µm (±2.67), respectively. The mean ‘correlation constant’ for TRT between the SD-OCT and histological sections was 0.96. The retinal thickness for all sublayers measured by SD-OCT vs. histology were also similar, the ‘correlation constant’ values ranged from 0.70 to 1.17. All SD-OCT and histological measurements demonstrated highly significant (p<0.01) strong positive correlations.

Conclusion

This study establishes conversion factors for the translation of ex vivo data into in vivo information; thus enhancing the applicability of SD-OCT in translational research.     

Discriminating between Glaucoma and Normal Eyes Using Optical Coherence Tomography and the ‘Random Forests’ Classifier

Purpose

To diagnose glaucoma based on spectral domain optical coherence tomography (SD-OCT) measurements using the ‘Random Forests’ method.

Methods

SD-OCT was conducted in 126 eyes of 126 open angle glaucoma (OAG) patients and 84 eyes of 84 normal subjects. The Random Forests method was then applied to discriminate between glaucoma and normal eyes using 151 OCT parameters including thickness measurements of circumpapillary retinal nerve fiber layer (cpRNFL), the macular RNFL (mRNFL) and the ganglion cell layer-inner plexiform layer combined (GCIPL). The area under the receiver operating characteristic curve (AROC) was calculated using the Random Forests method adopting leave-one-out cross validation. For comparison, AROCs were calculated based on each one of the 151 OCT parameters.

Results

The AROC obtained with the Random Forests method was 98.5% [95% Confidence interval (CI): 97.1–99.9%], which was significantly larger than the AROCs derived from any single OCT parameter (maxima were: 92.8 [CI: 89.4–96.2] %, 94.3 [CI: 91.1–97.6] % and 91.8 [CI: 88.2–95.4] % for cpRNFL-, mRNFL- and GCIPL-related parameters, respectively; P<0.05, DeLong’s method with Holm’s correction for multiple comparisons). The partial AROC above specificity of 80%, for the Random Forests method was equal to 18.5 [CI: 16.8–19.6] %, which was also significantly larger than the AROCs of any single OCT parameter (P<0.05, Bootstrap method with Holm’s correction for multiple comparisons).

Conclusions

The Random Forests method, analyzing multiple SD-OCT parameters concurrently, significantly improves the diagnosis of glaucoma compared with using any single SD-OCT measurement.     

Comparison of Corneal Epithelial and Stromal Thickness Distributions between Eyes with Keratoconus and Healthy Eyes with Corneal Astigmatism ≥2.0 D

Purpose

To identify corneal epithelial- and stromal-thickness distribution patterns in keratoconus using spectral-domain optical coherence tomography (SD-OCT).

Patients and Methods

We analyzed SD-OCT findings in 20 confirmed cases of keratoconus (group 1) and in 20 healthy subjects with corneal astigmatism ≥2 D (group 2). Epithelial and stromal thicknesses were measured at 11 strategic locations along the steepest and flattest meridians, previously located by corneal topography. Vertical mirrored symmetry superimposition was used in the statistical analysis.

Results

The mean maximum keratometry measurements in groups 1 and 2 were 47.9±2.9 D (range, 41.8–52.8) and 45.6±1.1 D (range, 42.3–47.5), respectively, with mean corneal cylinders of 3.3±2.2 D (range, 0.5–9.5) and 3.6±1.2 D (range, 2.0–6.4), respectively. The mean epithelial thickness along the steepest meridian in group 1 was the lowest (37.4±4.4 µm) at 1.2 mm inferotemporally and the highest (59.3±4.4 µm) at 1.4 mm supranasally from the corneal vertex. There was only a small deviation in thickness along the steepest meridian in group 2, as well as along the flattest meridians in both groups. The stromal thickness distribution in the two groups was similar to the epithelial, while the stromal thickness was generally lower in group 1 than in group 2.

Conclusions

SD-OCT provides details about the distribution of corneal epithelial and stromal thicknesses. The epithelium and stroma in keratoconic eyes were thinner inferotemporally and thicker supranasally compared with control eyes. The distribution pattern was more distinct in epithelium than in stroma. This finding may help improve the early diagnosis of keratoconus.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT02023619","term_id":"NCT02023619"}}NCT02023619     

Multimodal Retinal Vessel Analysis in CADASIL Patients

Purpose

To further elucidate retinal findings and retinal vessel changes in Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) patients by means of high resolution retinal imaging.

Methods

28 eyes of fourteen CADASIL patients and an equal number of control subjects underwent confocal scanning laser ophthalmoscopy (cSLO), spectral-domain optical coherence tomography (SD-OCT), retinal nerve fibre layer (RNFL) measurements, fluorescein and indocyanine angiography. Three vessel measurement techniques were applied: RNFL thickness, a semiautomatic software tool based on cSLO images and manual vessel outlining based on SD-OCT.

Results

Mean age of patients was 56.2±11.6 years. Arteriovenous nicking was present in 22 (78.6%) eyes and venous dilation in 24 (85.7%) eyes. Retinal volume and choroidal volume were 8.77±0.46 mm³ and 8.83±2.24 mm³. RNFL measurements showed a global increase of 105.2 µm (Control group: 98.4 µm; p = 0.015). Based on semi-automatic cSLO measurements, maximum diameters of arteries and veins were 102.5 µm (106.0 µm; p = 0.21) and 128.6 µm (124.4 µm; p = 0.27) respectively. Manual SD-OCT measurements revealed significantly increased mean arterial 138.7 µm (125.4 µm; p<0.001) and venous 160.0 µm (146.9; p = 0.003) outer diameters as well as mean arterial 27.4 µm (19.2 µm; p<0.001) and venous 18.3 µm (15.7 µm; p<0.001) wall thicknesses in CADASIL patients.

Conclusions

The findings reflect current knowledge on pathophysiologic changes in vessel morphology in CADASIL patients. SD-OCT may serve as a complementary tool to diagnose and follow-up patients suffering from cerebral small-vessel diseases.     

Retinal Thickening and Photoreceptor Loss in HIV Eyes without Retinitis

Purpose

To determine the presence of structural changes in HIV retinae (i.e., photoreceptor density and retinal thickness in the macula) compared with age-matched HIV-negative controls.

Methods

Cohort of patients with known HIV under CART (combination Antiretroviral Therapy) treatment were examined with a flood-illuminated retinal AO camera to assess the cone photoreceptor mosaic and spectral-domain optical coherence tomography (SD-OCT) to assess retinal layers and retinal thickness.

Results

Twenty-four eyes of 12 patients (n = 6 HIV-positive and 6 HIV-negative) were imaged with the adaptive optics camera. In each of the regions of interest studied (nasal, temporal, superior, inferior), the HIV group had significantly less mean cone photoreceptor density compared with age-matched controls (difference range, 4,308–6,872 cones/mm²). A different subset of forty eyes of 20 patients (n = 10 HIV-positive and 10 HIV-negative) was included in the retinal thickness measurements and retinal layer segmentation with the SD-OCT. We observed significant thickening in HIV positive eyes in the total retinal thickness at the foveal center, and in each of the three horizontal B-scans (through the macular center, superior, and inferior to the fovea). We also noted that the inner retina (combined thickness from ILM through RNFL to GCL layer) was also significantly thickened in all the different locations scanned compared with HIV-negative controls.

Conclusion

Our present study shows that the cone photoreceptor density is significantly reduced in HIV retinae compared with age-matched controls. HIV retinae also have increased macular retinal thickness that may be caused by inner retinal edema secondary to retinovascular disease in HIV. The interaction of photoreceptors with the aging RPE, as well as possible low-grade ocular inflammation causing diffuse inner retinal edema, may be the key to the progressive vision changes in HIV-positive patients without overt retinitis.     

Interobserver Agreement in Detecting Spectral-Domain Optical Coherence Tomography Features of Diabetic Macular Edema

PurposeTo evaluate interobserver agreement for the detection of spectral-domain optical coherence tomography (SDOCT) features of diabetic macular edema (DME).MethodCross-sectional study in which 2 retinal specialists evaluated SDOCT scans from eyes receiving treatment for DME. Scans from 50 eyes with DME of 39 patients were graded for features of DME including intra-retinal fluid (IRF), diffuse retinal oedema (DRE), hyper-reflective foci (HRF), subretinal fluid (SRF), macular fluid and vitreomacular traction (VMT). Features were graded as present or absent at zones involving the fovea, 1mm from the fovea and the whole scan of 49 line scans. Analysis was performed using cross-tabulations for percentage concordance and kappa values (κ).ResultsIn the 2950 line scans analysed, there was an increase in percentage concordance for DRE and HRF when moving from a foveal line scan, 1mm zone and then to a whole scan analysis (88% vs 94% vs 96%) and (88% vs 94% vs 94%) respectively with κ ranging from substantial to almost perfect. Percentage concordance for SRF was 96% at all 3 regions analysed, whilst IRF was 96% at fovea and 98% at higher number of line-scans analysed. Concordance for MF was 100% at fovea and 98% at 1mm zone and whole scan with almost perfect and substantial κ respectively. κ agreement was substantial for VMT at all regions analysed.ConclusionWe report a high level of interobserver agreement in the detection of SDOCT features of DME. This finding is important as detection of macular fluid is used to guide retreatment with anti-angiogenic agents.     

Intracameral Interleukin 1β, 6, 8, 10, 12p,Tumor Necrosis Factor α and Vascular Endothelial Growth Factor and Axial Length in Patients with Cataract

ObjectiveTo assess associations between the aqueous humour concentration of interleukin IL-1β, IL-6, IL-8, IL-10 and IL-12p, tumor necrosis factor α (TNF-α) and vascular endothelial growth factor (VEGF) and axial length in eyes with cataract.MethodsThe hospital-based investigation included patients who underwent cataract surgery between March 2014 and April 2014. Using aqueous humour collected at the start of cataract surgery, the interleukins IL-1β, IL-6, IL-8, IL-10 and IL-12p, TNF-α and VEGF were examined using a cytometric bead array. Axial length was determined by partial coherence laser interferometry (IOL Master).ResultsThe study included 33 patients with cataract (33 eyes) with a mean age of 69.2±10.8 years (range:50–87 years) and a mean axial length of 24.7±1.9 mm (range:22.6–31.5 mm). Lower aqueous concentration of VEGF was significantly associated with longer axial length (VEGF concentration (pg/mL) = -5.12 x Axial Length (mm) + 163; correlation coefficient r = -0.41; P<0.001) and more myopic refractive error (VEGF concentration (pg/mL) = 1.27xspherical equivalent (diopters)+44.8; r = 0.383; P = 0.002). The aqueous concentrations of all other substances were not significantly (all P>0.10) associated with axial length or refractive error.ConclusionsHigher intravitreal concentrations of VEGF were measured in eyes with a longer axial length, while the intraocular concentrations of IL-1β, IL-6, IL-8, IL-10, IL-12p and TNF-α were not correlated with axial length. The lower concentration of VEGF in axially elongated eyes may be one of the reasons for the lower prevalence of age-related macular degeneration and diabetic retinopathy in myopic eyes.     

Coronary Sinus Lead Removal: A Comparison between Active and Passive Fixation Leads

BackgroundImplantation of coronary sinus (CS) leads may be a difficult procedure due to different vein anatomies and a possible lead dislodgement. The mode of CS lead fixation has changed and developed in recent years.ObjectivesWe compared the removal procedures of active and passive fixation leads.MethodsBetween January 2009 and January 2014, 22 patients at our centre underwent CS lead removal, 6 active and 16 passive fixation leads were attempted using simple traction or lead locking devices with or without laser extraction sheaths. Data on procedural variables and success rates were collected and retrospectively analyzed.ResultsThe mean patient age was 67.2 ± 9.8 years, and 90.9% were male. The indication for lead removal was infection in all cases. All active fixation leads were Medtronic^® Attain StarFix^™ Model 4195 (Medtronic Inc., Minneapolis, MN, USA). The mean time from implantation for the active and passive fixation leads was 9.9 ± 11.7 months (range 1.0–30.1) and 48.7 ± 33.6 months (range 5.7–106.4), respectively (p = 0.012). Only 3 of 6 StarFix leads were successfully removed (50%) compared to 16 of 16 (100%) of the passive fixation CS leads (p = 0.013). No death or complications occurred during the 30-day follow-up.ConclusionAccording to our experience, removal of the Starfix active fixation CS leads had a higher procedural failure rate compared to passive.     

Metamorphopsia Associated with Branch Retinal Vein Occlusion

PurposeTo apply M-CHARTS for quantitative measurements of metamorphopsia in eyes with acute branch retinal vein occlusion (BRVO) and to elucidate the pathomorphology that causes metamorphopsia.MethodsThis prospective study consisted of 42 consecutive patients (42 eyes) with acute BRVO. Both at baseline and one month after treatment with ranibizumab, metamorphopsia was measured with M-CHARTS, and the retinal morphological changes were examined with optical coherence tomography.ResultsAt baseline, metamorphopsia was detected in the vertical and/or horizontal directions in 29 (69.0%) eyes; the mean vertical and horizontal scores were 0.59 ± 0.57 and 0.52 ± 0.67, respectively. The maximum inner retinal thickness showed no association with the M-CHARTS score, but the M-CHARTS score was correlated with the total foveal thickness (r = 0.43, p = 0.004), the height of serous retinal detachment (r = 0.31, p = 0.047), and the maximum outer retinal thickness (r = 0.36, p = 0.020). One month after treatment, both the inner and outer retinal thickness substantially decreased. However, metamorphopsia persisted in 26 (89.7%) of 29 eyes. The posttreatment M-CHARTS score was not correlated with any posttreatment morphological parameters. However, the posttreatment M-CHARTS score was weakly correlated with the baseline total foveal thickness (r = 0.35. p = 0.024) and closely correlated with the baseline M-CHARTS score (r = 0.78, p < 0.001).ConclusionsMetamorphopsia associated with acute BRVO was quantified using M-CHARTS. Initial microstructural changes in the outer retina from acute BRVO may primarily account for the metamorphopsia.     

Vertical and Horizontal Corneal Epithelial Thickness Profile Using Ultra-High Resolution and Long Scan Depth Optical Coherence Tomography

Purpose

To determine the vertical and horizontal thickness profiles of the corneal epithelium in vivo using ultra-long scan depth and ultra-high resolution spectral domain optical coherence tomography (SD-OCT).

Methods

A SD-OCT was developed with an axial resolution of ∼3.3 µm in tissue and an extended scan depth. Forty-two eyes of 21 subjects were imaged twice. The entire horizontal and vertical corneal epithelial thickness profiles were evaluated. The coefficient of repeatability (CoR) and intraclass correlation (ICC) of the tests and interobserver variability were analyzed.

Results

The full width of the horizontal epithelium was detected, whereas part of the superior epithelium was not shown for the covered super eyelid. The mean central epithelial corneal thickness was 52.0±3.2 µm for the first measurement and 52.3±3.4 µm for the second measurement (P>.05). In the central zone (0–3.0 mm), the paracentral zones (3.0–6.0 mm) and the peripheral zones (6.0–10.0 mm), the mean epithelial thickness ranged from 51 to 53 µm, 52 to 57 µm, and 58 to 72 µm, respectively. There was no difference between the two tests at both meridians and in the right and left eyes (P>.05). The ICCs of the two tests ranged from 0.70 to 0.97 and the CoRs ranged from 2.5 µm to 7.8 µm from the center to the periphery, corresponding to 5.6% to 10.6% (CoR%). The ICCs of the two observers ranged from 0.72 to 0.93 and the CoRs ranged from 4.5 µm to 10.4 µm from the center to the periphery, corresponding to 8.7% to 15.2% (CoR%).

Conclusions

This study demonstrated good repeatability of ultra-high resolution and long scan depth SD-OCT to evaluate the entire thickness profiles of the corneal epithelium. The epithelial thickness increases from the center toward the limbus.     

Validation of Smartphone Based Retinal Photography for Diabetic Retinopathy Screening

Aim

To evaluate the sensitivity and specificity of “fundus on phone’ (FOP) camera, a smartphone based retinal imaging system, as a screening tool for diabetic retinopathy (DR) detection and DR severity in comparison with 7-standard field digital retinal photography.

Design

Single-site, prospective, comparative, instrument validation study.

Methods

301 patients (602 eyes) with type 2 diabetes underwent standard seven-field digital fundus photography with both Carl Zeiss fundus camera and indigenous FOP at a tertiary care diabetes centre in South India. Grading of DR was performed by two independent retina specialists using modified Early Treatment of Diabetic Retinopathy Study grading system. Sight threatening DR (STDR) was defined by the presence of proliferative DR(PDR) or diabetic macular edema. The sensitivity, specificity and image quality were assessed.

Results

The mean age of the participants was 53.5 ±9.6 years and mean duration of diabetes 12.5±7.3 years. The Zeiss camera showed that 43.9% had non-proliferative DR(NPDR) and 15.3% had PDR while the FOP camera showed that 40.2% had NPDR and 15.3% had PDR. The sensitivity and specificity for detecting any DR by FOP was 92.7% (95%CI 87.8–96.1) and 98.4% (95%CI 94.3–99.8) respectively and the kappa (ĸ) agreement was 0.90 (95%CI-0.85–0.95 p<0.001) while for STDR, the sensitivity was 87.9% (95%CI 83.2–92.9), specificity 94.9% (95%CI 89.7–98.2) and ĸ agreement was 0.80 (95%CI 0.71–0.89 p<0.001), compared to conventional photography.

Conclusion

Retinal photography using FOP camera is effective for screening and diagnosis of DR and STDR with high sensitivity and specificity and has substantial agreement with conventional retinal photography.     

Retinal Arteriolar Morphometry Based on Full Width at Half Maximum Analysis of Spectral-Domain Optical Coherence Tomography Images

Objectives

In this study, we develop a microdensitometry method using full width at half maximum (FWHM) analysis of the retinal vascular structure in a spectral-domain optical coherence tomography (SD-OCT) image and present the application of this method in the morphometry of arteriolar changes during hypertension.

Methods

Two raters using manual and FWHM methods measured retinal vessel outer and lumen diameters in SD-OCT images. Inter-rater reproducibility was measured using coefficients of variation (CV), intraclass correlation coefficient and a Bland-Altman plot. OCT images from forty-three eyes of 43 hypertensive patients and 40 eyes of 40 controls were analyzed using an FWHM approach; wall thickness, wall cross-sectional area (WCSA) and wall to lumen ratio (WLR) were subsequently calculated.

Results

Mean difference in inter-rater agreement ranged from -2.713 to 2.658 μm when using a manual method, and ranged from -0.008 to 0.131 μm when using a FWHM approach. The inter-rater CVs were significantly less for the FWHM approach versus the manual method (P < 0.05). Compared with controls, the wall thickness, WCSA and WLR of retinal arterioles were increased in the hypertensive patients, particular in diabetic hypertensive patients.

Conclusions

The microdensitometry method using a FWHM algorithm markedly improved inter-rater reproducibility of arteriolar morphometric analysis, and SD-OCT may represent a promising noninvasive method for in vivo arteriolar morphometry.     

Reducing Short-Wavelength Blue Light in Dry Eye Patients with Unstable Tear Film Improves Performance on Tests of Visual Acuity

PurposeTo investigate whether suppression of blue light can improve visual function in patients with short tear break up time (BUT) dry eye (DE).MethodsTwenty-two patients with short BUT DE (10 men, 12 women; mean age, 32.4 ± 6.4 years; age range, 23–43 years) and 18 healthy controls (10 men, 8 women; mean age, 30.1 ± 7.4 years; age range, 20–49 years) underwent functional visual acuity (VA) examinations with and without wearing eyeglasses with 50% blue light blocked lenses. The functional VA parameters were starting VA, functional VA, and visual maintenance ratio.ResultsThe baseline mean values (logarithm of the minimum angle of resolution, logMAR) of functional VA and the visual maintenance ratio were significantly worse in the DE patients than in the controls (P < 0.05), while no significant difference was observed in the baseline starting VA (P > 0.05). The DE patients had significant improvement in mean functional VA and visual maintenance ratio while wearing the glasses (P < 0.05), while there were no significant changes with and without the glasses in the control group (P > 0.05),ConclusionsProtecting the eyes from short-wavelength blue light may help to ameliorate visual impairment associated with tear instability in patients with DE. This finding represents a new concept, which is that the blue light exposure might be harmful to visual function in patients with short BUT DE.     

Clinical Features and Course of Ocular Toxocariasis in Adults

Purpose

To investigate the clinical features, clinical course of granuloma, serologic findings, treatment outcome, and probable infection sources in adult patients with ocular toxocariasis (OT).

Methods

In this retrospective cohort study, we examined 101 adult patients diagnosed clinically and serologically with OT. Serial fundus photographs and spectral domain optical coherence tomography images of all the patients were reviewed. A clinic-based case-control study on pet ownership, occupation, and raw meat ingestion history was performed to investigate the possible infection sources.

Results

Among the patients diagnosed clinically and serologically with OT, 69.6% showed elevated immunoglobulin E (IgE) levels. Granuloma in OT involved all retinal layers and several vitreoretinal comorbidities were noted depending on the location of granuloma: posterior pole granuloma was associated with epiretinal membrane and retinal nerve fiber layer defects, whereas peripheral granuloma was associated with vitreous opacity. Intraocular migration of granuloma was observed in 15 of 93 patients (16.1%). Treatment with albendazole (400 mg twice a day for 2 weeks) and corticosteroids (oral prednisolone; 0.5–1 mg/kg/day) resulted in comparable outcomes to patients on corticosteroid monotherapy; however, the 6-month recurrence rate in patients treated with combined therapy (17.4%) was significantly lower than that in patients treated with corticosteroid monotherapy (54.5%, P = 0.045). Ingestion of raw cow liver (80.8%) or meat (71.2%) was significantly more common in OT patients than healthy controls.

Conclusions

Our study discusses the diagnosis, treatment, and prevention strategies for OT. Evaluation of total IgE, in addition to anti-toxocara antibody, can assist in the serologic diagnosis of OT. Combined albendazole and corticosteroid therapy may reduce intraocular inflammation and recurrence. Migrating feature of granuloma is clinically important and may further suggest the diagnosis of OT. Clinicians need to carefully examine comorbid conditions for OT. OT may be associated with ingestion of uncooked meat, especially raw cow liver, in adult patients.     

Retinal Thickness Normative Data in Wild-Type Mice Using Customized Miniature SD-OCT

Objective

To report normative data for retinal thickness in wild-type C57BL/6 mouse utilizing a miniature SD-OCT system.

Methods

Thirty adult mice (range: 3–5 months) were anesthetized and secured into the Bioptigen Spectral Domain Ophthalmic Imaging System. Right eye SD-OCT images were standardized by centralizing the optic nerve head (ONH) prior to image acquisition. Global and quadrant total retinal thickness (TRT) values were measured from retinal nerve fiber layer to retinal pigment epithelial layer. Posterior segment analyses also included the outer retinal layer (ORL) and inner retinal layer (IRL). Further sublayer analyses of four layers from the ORL and three layers comprising the IRL were also performed.

Results

The overall mean±SD global TRT in a C57BL/6 mouse model was 204.41±5.19 µm. Quadrant mean TRT values were 204.85±5.81 µm inferiorly, 204.97±6.71 µm nasally, 205.08±5.44 µm temporally, and 202.74±4.85 µm superiorly. Mean±SD thickness for ORL, and IRL were 126.37±10.01 µm, and 107.03±10.98 µm respectively. The mean±SD estimates for the four layers of the ORL were 18.23±2.73 µm, 26.04±4.21 µm, 63.8±6.23 µm, and 19.22±4.34 µm. Mean±SD values for the three IRL sublayers were 27.82±4.04 µm, 59.62±6.66 µm and 19.12±3.71 µm.

Conclusion

This study established normative values for the total retinal thickness and sublayer thickness for the wild-type C57BL/6 mice. Moreover, it provides a standard of retinal morphology, in a commonly used animal model, for evaluating therapeutic interventions and retinal disease pathophysiology.     

Objective Determination of Optimal Number of Spectral-Domain Optical Coherence Tomographic Images of Retina to Average

Purpose

To determine by objective methods the minimum number of spectral-domain optical coherence tomographic (SD-OCT) images to average to obtain the clearest retinal image.

Methods

SD-OCT Images were obtained from 9 healthy eyes and also from a phantom eye model. The SD-OCT images were obtained by averaging 1, 5, 20, 60, and 100 B-scan images. The reflectivity (mean gray value) of the different retinal layers was evaluated in these images. The image quality was evaluated by the size of the standard deviations (SDs) and the contrast-to-noise ratios (CNRs). A phantom eye model made by TiO₂ silicone plates was also examined.

Results

The SDs decreased significantly when the number of images averaged increased from 1 to 5 and also from 5 to 20 (P<0.05, post hoc Tukey''s honestly significant difference tests). The SD of the automatic real time averaging of 1 (ART = 1) and ART = 5 were significantly larger than the SD of ART = 100 (P<0.05). The SDs of all other averaged numbers were not significantly larger than that of ART = 100. The CNR increased with an increase in the number of images averaged, and there was a significant increase between ART = 1 to 5 and between ART = 5 to 20 (P<0.05). No significant differences in the CNR was observed between ART = 5, ART = 20 and ART = 60. Similar results were obtained with the phantom eye model.

Conclusions

Although the image quality of the SD-OCT images of the retina improved with an increase in the number of images averaged, it does not improve significantly by averaging more than 20 images.     

Central Retinal Venous Pressure in Eyes of Normal-Tension Glaucoma Patients with Optic Disc Hemorrhage

ObjectiveTo compare central retinal venous pressure (CRVP) among eyes with and without optic disc hemorrhage (ODH) in bilateral normal-tension glaucoma (NTG) patients and NTG eyes without an episode of ODH.MethodsIn this prospective study, 22 bilateral NTG patients showing a unilateral ODH and 29 bilateral NTG patients without an episode of ODH were included. Eyes were categorized into group A (n = 22, eyes with ODH), group B (n = 22, fellow eyes without ODH), and group C (n = 29, NTG eyes without an episode of ODH). A contact lens ophthalmodynamometer was used to measure CRVP and central retinal arterial pressure (CRAP).ResultsIntraocular pressure (IOP) measured on the day of contact lens ophthalmodynamometry showed no difference among groups. However, the mean baseline IOP in group A was significantly lower than that in group C (P = .008). The CRVP in group A (29.1 ± 10.8 mmHg) was significantly lower than that in group C (40.1 ± 8.8 mmHg, P = .001), but similar to that in group B (30.5 ± 8.7 mmHg, P = .409). A similar relationship was noted for CRAP. No significant eye-associated variable for ODH was found in group A and B by conditional logistic regression analysis (all P > 0.05). However, multivariate logistic regression analysis in groups A and C revealed that low mean baseline IOP (odds ratio [OR] = 0.69, 95% confidence interval [CI] 0.49-0.98, P = 0.043) and low CRVP (OR = 0.88, 95% CI 0.80-0.95, P = 0.003) were associated with ODH.ConclusionsCRVP was lower in NTG eyes with ODH than in eyes without an episode of ODH, but similar to that of fellow eyes without ODH. These imply less likelihood of association between increased central retinal venous resistance and ODH.