Assessment of macular ganglion cell complex using optical coherence tomography: Impact of a paediatric reference database in clinical practice

Values of peripapillary retinal nerve fibre layer thickness are different in children and adults

CLINICAL RELEVANCE

The detection of abnormal values of peripapillary nerve fibre layer (pRNFL) thickness measured with optical coherence tomography (OCT) is important for detecting optic nerve disease in children.

BACKGROUND

To evaluate the level of agreement between the adult reference database supplied with an OCT device and the present paediatric study database for the measurement of pRNFL thickness in children. This study also aimed to provide reference values for pRNFL thickness according to the spherical equivalent in the paediatric population.

METHODS

This was a cross-sectional study. One hundred and twenty-six healthy children were included, who had undergone a full ophthalmological examination including cycloplegic refraction and examination of pRNFL thickness using the Topcon 3D OCT 2000 device (Topcon Corporation, Tokyo, Japan). Values equal to or below the fifth percentile (≤p5) and above the 95th percentile (>p95) were considered abnormal. Observed agreement and specific agreement were investigated between OCT measurements classified with paediatric and adult reference values for normality.

RESULTS

Values ≤ p5 in the adult database were recorded for 2 of the 30 values (6.6%) of the pRNFL values by quadrants ≤p5 in the paediatric database and 17 of the 88 (19.3%) values by sectors ≤p5. For values >p95 in the adult database, 88% by quadrants and 72% by sectors would have been classified as being within the normal range using the paediatric database.

CONCLUSION

The use of adult reference values currently available in OCT devices can lead to classification errors concerning the normal range of pRNFL thickness in a large proportion of paediatric patients. The use of normative paediatric databases, such as the one discussed in this study, should be taken into consideration.

Foveal thickness and its association with visual acuity in adults born preterm with very low birth weight: A two-country birth cohort study

PURPOSE

To explore foveal and parafoveal thickness in adults born preterm with very low birth weight (VLBW) and its association with best-corrected visual acuity (BCVA) and gestational age (GA) compared to adults born at term.

METHODS

In a joint study of the Helsinki Study of Very Low Birth Weight Adults (Finland) and the NTNU Low Birth Weight Life study (Norway), 106 VLBW and 143 term-born controls were examined with spectral-domain optical coherence tomography and BCVA at age 31-43 years. Thickness of retinal layers was segmented in the foveal and parafoveal areas of the macula.

RESULTS

The total retinal thickness in the foveal area was thicker in VLBW adults compared with controls; mean (SD): 292.5 μm (28.2) and 272.4 μm (20.2); p < 0.001, and thinner in the parafoveal areas of the macula. These findings could be explained by a thicker inner retinal layer in the foveal area found in VLBW adults compared with controls (mean difference 20.4 μm; CI: 15.0 to 25.9), where a thicker fovea was associated with lower GA, but not BCVA.

CONCLUSION

Adults born preterm with VLBW had a thicker retina in the foveal area than controls and this was associated with GA, but not with BCVA. These changes seem to be related to a thicker inner retinal layer in VLBW adults. The findings imply that signs of macular underdevelopment are still present in adulthood, but not necessarily related to reduced visual function.

Macular thickness variation and interocular symmetry by gestational age in preterm school-age children

PURPOSE

To determine changes in macular thickness profile according to gestational age (GA) and to assess interocular symmetry in the macula of children born very preterm.

METHODS

In this cross-sectional study of preterm (n = 106) and term-born (n = 49) children 5-8 years of age at time of examination, optical coherence tomography was used to measure macula thickness as described in the ETDRS study. Statistical analyses included stratified and multivariable analyses.

RESULTS

Foveal minimum thickness increased with decreasing GA (P for trend, <0.001; 254.7 ± 32.8 μm for children born at 24-25 weeks and 193.2 ± 32.8 μm in term-born children). Inner and outer area thickness differed for term and preterm children, but did not vary with the degree of prematurity (inner area, 267.0 ± 11.0 μm for 24-25 weeks' GA and 305.4 ± 11.8 μm for term children [P < 0.01]; outer ring, 305.5 ± 10.4 μm in extreme preterm and 271.0 ± 10.4 μm in term children [P < 0.01]). Interocular asymmetry in preterm children was not significant for most areas; the largest interocular difference was found in the central zone (16.3 ±16.6 μm).

CONCLUSIONS

In our study cohort, children born very preterm examined at school age compared to term born children had greater central thickness with decreased foveal pit, decreased inner ring, and increased thickness of the outer ring. They did not show greater interocular asymmetry.

Normative Data of Macular Thickness Using Spectral Domain Optical Coherence Tomography for Healthy Jordanian Children

Purpose

To report normative values of macular thickness and volume by spectral-domain optical coherence tomography (SD-OCT) in the eyes of healthy Jordanian children aged 6–16 years and assess the correlation of macular parameters with age, sex, and refractive error.

Patients and Methods

This observational study included 144 eyes of 144 healthy children. All children underwent comprehensive ocular examination and cycloplegic refraction. Average macular thickness, macular volume, central subfield thickness (CST), and macular thickness for all the Early Treatment Diabetic Retinopathy Study (ETDRS) quadrants were obtained using Primus SD-OCT (Carl Zeiss Meditec).

Results

The study group consisted of 68 boys and 76 girls with a mean age (SD) of 10.8 (3.0) years. The mean (SD) spherical equivalent refraction (SER) was 0.56 (1.73) diopters (range: −4.75 to 4.75). The mean of macular average thickness was 277.2±12.5 μm, and the mean of the central subfield thickness was 246.7±16.8 μm. In multivariate analysis, all macular parameters except the central subfield thickness (CST) correlated positively with the SER. Boys had significantly higher CST than girls (p=0.008). None of the macular parameters were correlated with age.

Conclusion

Normative data of macular thickness for healthy Jordanian children were established for sex and age groups using SD-OCT.

Retinal ganglion cell complex thickness at school-age, prematurity and neonatal stressors

PURPOSE

To investigate the association between the ganglion cell complex (GCC) thickness at early school-age and prematurity and other neonatal factors.

METHODS

Cross-sectional study. The sample included very preterm children with gestational age (GA) below 32 weeks or birthweight below 1500 g enrolled in a follow-up program (n = 101) and a comparison group of term-born children (n = 49). Ganglion cell complex (GCC) thickness was measured at 4-8 years using high-quality optical coherence tomography (OCT) images. Data on neonatal and postnatal features were extracted from clinical records; analyses included mixed linear models.

RESULTS

Ganglion cell layer (GCL) and retinal nerve fiber layer (mRNFL) were thicker in term than in preterm born children (2.9 μm and 2.4 μm respectively, p < 0.001). Within the preterm group, lower GA was associated with a decrease in total GCL (0.7 μm per week, p < 0.001). Being small for GA was associated with further thinning in both layers (1.4 and 2.8 µm). Postnatal corticosteroids therapy and severe brain lesion were associated with thinning in the total GCL of 6 µm (p < 0.001) and 4.1 µm (p = 0.002), respectively, and shock was associated with thinning in total mRNFL of 6 µm (p < 0.001).

CONCLUSIONS

Lower GA or birthweight are associated with thinning of GCC layers. When performing an OCT examination at school-age and a decrease in GCC thickness is observed, it may be relevant to ask about a history of prematurity, and further enquire about neonatal shock, postnatal corticosteroids therapy or severe brain lesion that are related to additional decrease in GCC thickness.

Normative data for optical coherence tomography in children: a systematic review

The purpose of this study is to systematically review the reported data of normal optical coherence tomography (OCT) results in the paediatric population. A systematic literature search was performed using the PubMed, Embase, and Web of Science databases, using the keywords "optical coherence tomography"; "normative data" or "healthy eyes"; "children" or "paediatric population". Studies with at least 50 participants were included, irrespective of the OCT equipment employed. We excluded the OCT angiography studies or the studies investigating the choroidal thickness. Seventy-four studies were included in the final analysis and information on study design, number of participants, demographic characteristics, type of OCT equipment, OCT parameters and results was collected. Due to the high variability of OCT instruments and parameters used, a meta-analysis was not feasible. We report the normative values for the peripapillary retinal nerve fibre layer thickness and the macular retinal thickness for each ETDRS quadrant, as provided by the studies included in the present analysis. We also report the influence of ethnicity, age, gender, eye laterality, ISNT rule, spherical equivalent, and axial length on OCT results.

Choroidal, macular and ganglion cell layer thickness assessment in Caucasian children measured with spectral domain optical coherence tomography

PURPOSE

To study the subfoveal choroidal thickness (SFCT), macular ganglion cell layer (GCL-IPL) and central macular thickness (CMT) in Caucasian children, and to analyze these optical coherence tomography (OCT) parameters depending on the spherical equivalent (SE).

METHODS

Cross-sectional study of SFCT, GCL-IPL, and CMT in Caucasian children, analyzed with spectral-domain OCT Cirrus 5000 and Enhanced-depth imaging technique. Correlation between these three OCT parameters, age, sex, and spherical equivalent was analyzed. The eyes were classified into three groups: group 1 included eyes with SE < 0, group 2 included eyes with SE between 0 and +2.00, and group 3 eyes with SE > +2.00.

RESULTS

Hundred ninety-eight eyes of 121 subjects were studied. The mean age was 9.22 years (range 3-16); 61.1% were female. The mean SFCT was 351.04 ± 84.08 µm, being 310.04 ± 82.84µm in group 1 (n = 62), 373.14 ± 83.16 µm in group 2 (n = 71) and 365.18 ± 73.16 µm in group 3 (n = 65); statistically significant differences were found between groups 2 and 3, compared with group 1. GCL-IPL thickness was significantly thinner (p < 0.001) in group 1, compared with group 3. There were no statistically significant differences between the three groups regarding CMT. Correlation with age, and sex was not found.

CONCLUSIONS

SFCT and GCL-IPL thickness were significantly thinner (p < 0.001) in myopic children when compared with a non-myopic pediatric population. However, it seems that there is not a correlation among the three OCT parameters studied, age and sex, when they are analyzed depending on refractive error.

Measurement of macular thickness with optical coherence tomography: impact of using a paediatric reference database and analysis of interocular symmetry

PURPOSE

Optical coherence tomography (OCT) software is used to classify abnormality of macular thickness by colour category based on reference data from adult series. We assessed the impact of using paediatric reference thickness values for macular thickness instead of adult reference values.

METHODS

Cross-sectional study. Primary and tertiary healthcare setting. Out of 140 healthy participants aged 5 to 18 years, 126 were eligible, 83% from European origin. Following a dilated eye examination and cycloplegic refraction, participants underwent macular scanning with OCT (Topcon 3D OCT-2000). Macular thickness paediatric reference values were recorded by spherical equivalent (SE) and sex, and the specific agreement between paediatric and adult reference values below or equal to percentile 5 and above percentile 95 was estimated. The absolute interocular differences for all macular parameters were determined.

RESULTS

Multivariate regression analysis confirmed statistically independent positive associations between SE and average thickness, total volume, and temporal and inferior outer quadrants (all p values ≤ 0.003). The analysis also revealed higher values in males for average thickness, central thickness, and all inner macula quadrants (all p values ≤ 0.039). The use of the adult database only detected 49% of the extreme values (≤ p5 and > p95) in our paediatric sample. The 95th percentile limits for absolute interocular differences for all macular parameters ranged from 12 to 17 μm.

CONCLUSIONS

OCT-based macular reference values for paediatric SE and sex improve detection of children with abnormal macular thicknesses. Interocular differences exceeding standard references for macular parameters should be considered for further examinations.

Interobserver reproducibility and interocular symmetry of the macular ganglion cell complex: assessment in healthy children using optical coherence tomography

Background

Assessment of interobserver reproducibility and interocular symmetry using optical coherence tomography (OCT)–based measurements of the macular ganglion cell complex (GCC) in healthy children facilitates interpretation of OCT data. We assessed the interobserver reproducibility and interocular symmetry of GCC and evaluated candidate determinants.

Methods

This was a cross-sectional study performed in a primary and tertiary health-care setting. A total of 126 healthy participants aged 5 to 18 years were eligible. GCC scans were performed by 4 operators using the Topcon 3D OCT-2000 device. Intraclass correlation coefficients (ICCs) were used to estimate reproducibility and symmetry. Cut-off points for symmetry were defined as the 95th percentile of the absolute interocular difference for 6 GCC parameters. Percentile distributions of interocular difference were generated based on age and difference in absolute interocular spherical equivalent (SE).

Results

The reproducibility ICC ranged from 0.96 to 0.98 for all 6 GCC parameters. Cut-off points for interocular symmetry of the superior and inferior quadrants and total macular retinal nerve fibre layer thickness (mRNFL) and macular ganglion cell layer-inner plexiform layer thickness were 3.5, 4.5, 3.0, 3.0, 2.5, and 2.5 μm respectively. A positive association was observed between the absolute interocular difference of SE and superior and total mRNFL symmetry values (p = 0.047 and p = 0.040, respectively).

Conclusions

OCT measurements of GCC in healthy children show excellent reproducibility. Interocular differences in SE should be assessed when mRNFL differences exceed the 95% cut-off. These findings can contribute to establish reference values for interocular symmetry in paediatric GCC parameters.

Evaluation of the association of macular ganglion cell-inner plexiform layer thickness and myopia in Chinese young adults

PURPOSE

To describe the distribution of ganglion cell-inner plexiform layer (GCIPL) thickness among Chinese young adults and report whether the decreased GCIPL thickness is associated with myopia.

METHODS

In this study, we included Chinese young adults who underwent Cirrus spectral domain-optical coherence tomography (SD-OCT). SD-OCT was used to measure average and minimum GCIPL thickness, and GCIPL thickness at all sectors. Subfoveal choroidal thickness (CT), axial length (AL), and spherical equivalents (SE) were also measured.

RESULTS

A total of 348 eyes were included in the analysis. Average GCIPL thickness showed a significant difference between myopes and emmetropes, with 87.89 ± 3.65 μm for emmetropic groups and 82.65 ± 4.96 μm for myopic groups. The GCIPL thickness was significantly thinner in myopia than in emmetropia at all locations (P < 0.05), affirming that myopia was associated with thinner GCIPL thickness (P = 0.001). The mean subfoveal CT also showed a significant difference between myopes and emmetropes, with 330.57 ± 9.43 μm for emmetropic groups and 265.98 ± 4.12 μm for myopic groups. GCIPL (OR 0.863, 95% CI, 0.785-0.949), AL (OR 2.499, 95% CI, 1.532-4.075) and intraocular pressure (IOP) (OR 1.250, 95% CI, 1.086-1.438) revealed significant associations with myopia. When adjusting for AL, IOP, and anterior chamber depth (ACD) in the myopia subgroup, the GCIPL thickness remained positively associated.

CONCLUSIONS

In a specific Chinese young population, myopic eyes have measurably less macular GCIPL thickness than normal eyes. Decreasing GCIPL thickness may be associated with the progression of myopia.

Ganglion Cell Complex Analysis in Glaucoma Patients: What Can It Tell Us?

Glaucoma is a group of optic neuropathies characterized by a progressive degeneration of retina ganglion cells (RGCs) and their axons that precedes functional changes detected on the visual field. The macular ganglion cell complex (GCC), available in commercial Fourier-domain optical coherence tomography, allows the quantification of the innermost retinal layers that are potentially involved in the glaucomatous damage, including the retinal nerve fiber (RNFL), ganglion cell and inner plexiform layers. The average GCC thickness and its related parameters represent a reliable biomarker in detecting preperimetric glaucomatous damage. The most accurate GCC parameters are represented by average and inferior GCC thicknesses, and they can be associated with progressive visual field loss. Although the diagnostic accuracy increases with more severe glaucomatous damage and higher signal strength values, it is not affected by increasing axial length, resulting in a more accurate discrimination of glaucomatous damage in myopic eyes with respect to the traditional RNFL thickness. The analysis of the structure-function relationship revealed a good agreement between the loss in retinal sensitivity and GCC thickness. The use of a 10-2° visual field grid, adjusted for the anatomical RGCs displacement, describes more accurately the relationship between RGCs thickness and visual field sensitivity loss.

Paediatric optical coherence tomography normative databases: A real need

INTRODUCTION

Optical coherence tomography (OCT) has become an essential tool in paediatric ophthalmology. However, none of the currently available OCT devices include any kind of normative database for the paediatric population, which can lead to important interpretation errors.

OBJECTIVE

To review the paediatric OCT normative databases.

MATERIAL AND METHODS

The applications and implications of the use of paediatric OCT normative databases are reviewed.

RESULTS

The paediatric normative databases that have been published so far in scientific literature with different OCT devices for Spanish and European population are presented.

CONCLUSIONS

The knowledge and interpretation of paediatric OCT normative databases in our daily clinical practice is crucial in order for the correct interpretation of OCT thickness maps.