Outer Macular Thickness Research Articles

Determinants of Macular Thickness Using Spectral Domain Optical Coherence Tomography in Healthy Eyes: The Singapore Chinese Eye Study

We determined ocular and systemic factors influencing macular thickness measured by spectral-domain optical coherence tomography (SD-OCT) in a population-based sample of healthy eyes. We recruited 490 healthy Chinese adults, aged 40 to 80 years, from the Singapore Chinese Eye Study, a population-based survey. All participants underwent a comprehensive eye examination and a standardized interview. The SD-OCT (Cirrus HD-OCT, software version 6.0) was used to measure a range of macular thickness parameters (central foveal subfield thickness, average inner macular thickness, average outer macular thickness, overall average macular thickness, and overall macular cube volume). Linear regression analyses were performed to examine the effects of various ocular and systemic factors on macular thickness. The mean (standard deviation) age of the subjects was 53.17 (6.14) years and 50.0% of them were male. The mean central foveal subfield, average inner, and average outer macular thicknesses were 250.38 (20.58), 319.33 (14.40), and 276.67 (11.94) μm, respectively. The overall average macular thickness was 280.25 (11.42) μm and overall macular cube volume was 10.09 (0.41) mm(3). Sex, age, and axial length (AL) are the factors that influenced macular thicknesses. Thinner overall average macular thickness was associated with female sex (4.46 μm thinner compared to males, P < 0.001), older age (0.38 μm decrease per each year increase in age, P < 0.001), and longer AL (2.34-μm decrease per each mm increase in AL, P < 0.001), whereas thinner central foveal subfield thickness was associated with female sex (13.5 μm thinner compared to males, P < 0.001) and shorter AL (3.33-μm decrease per each mm increase in AL, P < 0.001). Female sex, older age, and longer AL were associated independently with thinner overall average macular thickness, whereas female sex and shorter AL were associated with thinner central foveal thickness in ethnic Chinese. These factors should be taken into consideration when interpreting macular thickness measurements with SD-OCT.

Effect of multizone refractive multifocal contact lenses on the Cirrus HD OCT retinal measurements

BackgroundSimultaneous vision multifocal contact lenses are widely used to alleviate the symptoms of presbyopia. These contact lenses create simultaneous retinal images due to the incoming light distribution being divided into two or more focuses. Our aim was to evaluate whether the multizone refractive multifocal contact lenses affect the measurements of the retinal nerve fibre layer (RNFL) and macular thickness using optical coherence tomography (OCT).MethodsIn this cross‐over study, 30 eyes of 30 subjects with a mean age of 50.42 ± 7.82-years were fitted with multizone refractive multifocal contact lenses. Using the Thickness Analysis mode of the Cirrus HD (Carl Zeiss, Meditec, Dublin, CA, USA) OCT, the average, superior, nasal, inferior, temporal and 12 o'clock‐hour retinal nerve fibre layer thicknesses were obtained. In Macular Thickness Analysis mode of Cirrus HD OCT, the average cube thickness, macular cube volume, central subfield thickness, inner and outer macular thickness (superior, inferior, nasal and temporal area) were obtained. Measurements were performed with and without contact lenses.ResultsStatistically significant differences were not found in RNFL thickness at any of the studied areas and for 12 o'clock‐hour sectors analysed (p > 0.07). The mean macular volume was 9.86 ± 0.30 mm3 and 9.87 ± 0.27 mm3 with and without multifocal contact lenses, respectively (p = 0.38). There were no statistically significant differences in average macular thickness or macular thickness of areas analysed between the measurements with and without multifocal contact lenses (p > 0.09). The signal strength was higher than seven for all scans, and differences were not found in the mean of signal strength between the measurements with and without contact lenses.ConclusionsThe results of this study suggest that the assessed multizone refractive multifocal contact lens does not affect the retinal nerve fibre layer and macular thickness measurements using Cirrus HD OCT.

Correlation Between Macular Thickness and Glaucomatous Visual Fields

The purpose of the study was to establish whether predictable structural relationships exist between macular thickness parameters and anatomically related visual field (VF) defects. The optical coherence tomography (OCT) macular scans and automated VFs of 127 eyes of 127 glaucoma patients were examined retrospectively. The macular scan parameters recorded included the superior inner and outer sectors and the inferior inner and outer sectors. For the VFs, the threshold sensitivities of the central 4×4 points were recorded. The 16 points were grouped into superior outer, superior inner, inferior inner, and inferior outer rows, and the mean of each row was calculated. The OCT macular scan sectors and the VF rows were compared using the Spearman correlation. Statistically significant structural relationships between each macular parameter and its anatomically related VF defect were noted in this study. Highest correlations were found between the inferior outer macular thickness and the superior outer VF region, the inferior inner macular and the superior inner VF region, the superior inner macula and the inferior inner VF region, and the superior outer macula and the inferior outer VF region. As a predictable and significant structural relationship exists between macular thickness and VF defects, macular scan OCT should be studied further and considered more carefully in the diagnosis and management of glaucoma.

Macular thickness as determined by optical coherence tomography in relation to degree of myopia, axial length and vitreous chamber depth in Malay subjects

Purpose: This study aimed to determine the relationship between macular thickness and spherical equivalent refraction (SER), axial length (AL) and vitreous chamber depth (VCD) in Malay subjects.Methods: Sixty‐three subjects (aged 19–24-years) with a mean SER of ‐1.79 ± 2.24-D, mean axial length of 24.26 ± 1.35-mm and mean vitreous chamber depth of 17.02 ± 1.33-mm were included in this clinical cross‐sectional study. Stratus optical coherence tomography (Time Domain optical coherence tomography) was used to determine the thickness of the outer macular (perifovea) and inner macular (parafovea) at four different locations, that is, temporal, superior, nasal and inferior quadrants and also the fovea itself.Results: Positive correlations were found between the outer macular (perifovea) thickness and SER at the temporal (R = 0.47, p < 0.05), superior (R = 0.36, p < 0.05) and inferior (R = 0.31, p < 0.05) quadrants. Foveal thickness was also positively correlated with AL (R = 0.34, p < 0.05) and VCD (R = 0.32, p < 0.05). Negative correlations were found between outer macular thickness and axial length at the temporal (R = ‐0.46, p < 0.05), superior (R = ‐0.27, p < 0.05), nasal (R = ‐0.25, p < 0.05) and inferior (R = ‐0.36, p < 0.05) quadrants. Negative correlations were also found between outer macular thickness and VCD at the temporal (R = ‐0.51, p < 0.05), superior (R = ‐0.32, p < 0.05), nasal (R = ‐0.31, p < 0.05) and inferior (R = ‐0.40, p < 0.05) quadrants.Conclusions: This study shows that the degree of myopia and elongation of the globe are associated with thinning of most areas of the perifovea. A trend for foveal thickening in the high myopia group is also inferred, although this does not apply to the low and moderate myopia groups.

Macular parameters and prematurity: A spectral domain coherence tomography study

To investigate the association of premature birth with macular parameters measured by spectral domain coherence tomography (SD-OCT). The Sydney Adolescent Vascular and Eye Study performed eye examinations in school students across Sydney between 2009 and 2011. Visual acuity, cycloplegic autorefraction, and optical biometry measurements were recorded. Macular parameters were measured with SD-OCT. Questionnaires previously completed by the participants' parents were used to determine perinatal and medical history. Children with retinal disease or a known history of retinopathy of prematurity were excluded from the analysis. Macular measurements from the right eye of 1,672 participants ages 10-19 years were analyzed. The central subfield in those born at ≤32 weeks' gestational age was significantly thicker than those born at ≥37 weeks' gestational age (266.3 μm vs 251.7 μm, P = 0.0007). The average cube thickness and average outer macular ring thickness were smaller in those born at ≤32 weeks compared with those born at ≥37 weeks (P = 0.03 and 0.02, respectively). Similarly, the cube volume was smaller in the ≤32 weeks' group compared with the ≥37 weeks' group (P = 0.04). No significant differences were found between the 33-36 weeks' group and the ≥37 weeks' group. In comparison to babies born at term, thicker central maculas and thinner macular outer rings were found in children born <33 weeks gestational age when measured by SD-OCT at ages 10-19 years.

Macular Measurements Using Optical Coherence Tomography in Healthy Chinese School Age Children

To evaluate macular thickness/volume in a Chinese population of primary school children using optical coherence tomography (OCT), and assess its association with age, sex, spherical equivalent refraction (SE), body mass index (BMI), and intraocular pressure (IOP). Healthy Chinese children (n = 806) from six randomly selected primary schools in Chongming County, Shanghai, China, were enrolled. Comprehensive standardized ophthalmic examinations included visual acuity, cycloplegic refraction, IOP, and fast macular scans using Stratus OCT. Mean values for the nine Early Treatment Diabetic Retinopathy Study (ETDRS) areas, foveal minimum thickness, and macular volume were calculated. OCT data from right eyes with high-quality scans were evaluated in 720 children (89.3% of total participants; 46.5% boys). Macular thickness and volume were normally distributed. The mean foveal minimum thickness was 140.0 ± 12.3 μm. There were significant differences between the boys and the girls in mean foveal volume (P = 0.023) and sectoral macular thickness in all the quadrants of the inner ring (P < 0.001 and P = 0.001) and temporal outer quadrant (P = 0.009). SE refraction correlated positively with inner and outer macular thickness and total macular volume (P < 0.001) and negatively with central macular volume (P = 0.012). BMI correlated significantly only with outer macular thickness (r = 0.074, P = 0.048). No age- and IOP-related differences were found in the macular parameters. OCT demonstrated that macular thickness/volume was normally distributed in this sample of Chinese children, with variations in sex and SE. The variables in macular thickness/volume should be considered when diagnosing and monitoring school-aged children with diseases that affect the macula.

A Prospective Study of Macular Thickness in Amblyopic Children with Unilateral High Myopia

To compare macular thickness of the normal fellow eye to that of the amblyopic eye using optical coherence tomography (OCT) in children with unilateral high myopia. Relationships between macular thickness and magnitude of myopic anisometropia, axial length, and visual acuity (VA) were investigated. Thirty-one children with a mean age of 9.56 years were recruited. Macular thickness, axial length, best-corrected VA, and refraction were measured. Paired t-test was performed to compare the macular thickness of the amblyopic eye to that of the fellow eye. Partial correlations were used to test the relationships between interocular difference in macular thickness and anisometropia, axial length, and VA. Average (± SD) LogMAR VA in the amblyopic eye was 0.96 ± 0.31. Mean spherical equivalent in amblyopic eyes was -10.79 ± 3.40 diopters. A statistically significant difference in macular thickness was found between amblyopic and fellow eyes, with amblyopic eyes having greater foveal thickness but reduced inner and outer macular thickness. Only the nasal outer macular thickness had a statistically significant association with the magnitude of anisometropia. Amblyopic children with unilateral high myopia tend to have a thicker fovea and thinner inner and outer macula in the amblyopic eye compared to the normal fellow eye. The findings indicate that anatomic changes may be present in the retinas of amblyopic children with unilateral high myopia. Future study is warranted to determine whether the mechanism of the macular changes is due to high myopia, amblyopia, or a combination of the two.

Changes in retinal nerve fibre layer, optic nerve head morphology, and visual field after acute primary angle closure

To determine and correlate the long-term changes in retinal nerve fibre layer (RNFL) thickness, optic nerve head (ONH) morphology, and visual fields after a single episode of acute primary angle closure (APAC). This was a cross-sectional comparative study of patients at National University Hospital (Singapore) from 2000 to 2006 after an episode of unilateral APAC. The peripapillary and macular RNFL were measured using Stratus optical coherence tomography (OCT) and ONH configuration was assessed using Heidelberg Retina Tomography (HRT)-III. Humphrey perimetry was also performed, and the presence of disc pallor was noted. APAC eyes were compared with fellow eyes as matched controls. Twenty-five patients were assessed at a median of 33 months (range, 11-85 months) after APAC. OCT showed that there was a reduction in the peripapillary and outer macular RNFL thickness in APAC eyes compared with controls. Humphrey perimetry revealed significantly reduced mean deviation (P=0.006) and increased pattern standard deviation (P=0.045) in APAC eyes compared with controls. HRT-III showed no difference in mean rim area, rim volume, or cup-disc ratio between APAC eyes and controls. Disc pallor was present in nine APAC eyes (36%) but was absent in fellow eyes (P=0.002), and was associated with peripapillary RNFL thinning, visual field loss, and an increased interval between the onset of symptoms and normalization of intraocular pressure (P=0.023). APAC results in peripapillary and outer macular RNFL loss, visual field defects, and optic disc pallor, even in cases in which the ONH configuration remains unchanged.

Retinal Thickness in the Offspring of Diabetic Pregnancies

To compare macular and peripapillary retinal nerve fiber layer (RNFL) thickness in children from diabetic compared with nondiabetic pregnancy. Cross-sectional study. As part of the Sydney Myopia Study, 2367 children from grade 7 (age range 11.1 to 14.4 years) completed detailed ocular examinations during 2004-2005. Examination included determination of best-corrected visual acuity (logarithm of minimal angle of resolution) and autorefraction after cycloplegia. Axial length was measured using noncontact interferometry. Optical coherence tomography (OCT) was performed using Stratus OCT through dilated pupils. Participants and parents completed comprehensive questionnaires including questions on birth parameters and medical history. There were 1741 and 1687 children with adequate-quality RNFL and macular scans respectively, who had complete examination and questionnaire data. There were 57 children from diabetic pregnancies who had both RNFL and macular scans. Children from diabetic pregnancies had significantly thinner inner (264.9 μm vs 270.2 μm, P = .007) and outer (231.9 μm vs 238.6 μm, P = .0001) macular thickness and macular volume (6.75 mm(3) vs 6.92 mm(3), P = .0003) compared with children from nondiabetic pregnancies. However, central macular thickness, foveal minimum thickness, and RNFL parameters were not significantly different between the 2 groups. Diabetes during pregnancy is associated with changes in retinal morphology in the offspring. Thinning of the pericentral macular parameters was evident in Stratus OCT scans of children from diabetic pregnancies. These findings suggest the possibility that maternal diabetes impacts on the development of the retina.

Macular Thickness Variations with Sex, Age, and Axial Length in Healthy Subjects: A Spectral Domain–Optical Coherence Tomography Study

To assess the relationship between macular retinal thickness and volume and age, sex, and refractive error/axial length with spectral domain-optical coherence tomography (SD-OCT). One randomly selected eye of 198 consecutive ophthalmically normal subjects (104 men, 94 women) between July 2008 and January 2009, with corrected visual acuities better than 20/30 were included in this cross-sectional study. Complete ophthalmic examination, axial length measurement with a laser interferometer, and macular cube 512 x 128 scan by SD-OCT were performed. The mean age was 55.6 +/- 16.4 years (range, 17-83), average refractive error was -2.17 +/- 4.82 (range, -23.50-3.75), and average axial length was 24.73 +/- 1.98 mm (range, 21.52-32.51). The central subfield thickness, average inner macular thickness, and overall macular volume were significantly lower in the female subjects (partial correlation: P = 0.009, P = 0.027, and P = 0.042, respectively). As age increased, average inner macular thickness, average outer macular thickness, overall average macular thickness, and macular volume decreased significantly (partial correlation: P = 0.002, P = 0.002, P = 0.002, and P = 0.000, respectively). Refractive error had no significant influence in partial correlation analysis. Axial length correlated negatively with average outer macular thickness, overall average macular thickness, and macular volume (partial correlation: P = 0.006, P = 0.044, and P = 0.003, respectively). In normal subjects, SD-OCT showed that retinal thickness is related to age, sex, and axial length, with regional variations.

Optical Coherence Tomography in the Eyes of Normal Children

To collect a normative database of macular thickness, retinal nerve fiber layer (RNFL) thicknesses, and optic nerve topography in the healthy eyes of children aged 3 to 17 years using optical coherence tomography (OCT) measurements. Scans were obtained for 286 healthy children (black, 114; white, 154; other, 18). Each child had a dilated eye examination, an axial length measurement using the IOL Master (Carl Zeiss Meditec, Dublin, California), and OCT measurements using the fast macular map, fast RNFL thickness, and fast optic disc protocols of the Stratus OCT (OCT-3; Carl Zeiss Meditec). Black children had smaller macular volume and foveal thickness, larger RNFL thickness, and larger cup-disc area ratios compared with white children. Macular volume and average outer macular thickness correlated negatively with axial length in white children. Foveal thickness correlated positively with age in black children only. Average RNFL correlated negatively with axial length in white children only (P < .05 for all). Normative data for all variables were recorded and compared with reported adult values. Stratus OCT-3 measurements of macular and RNFL thickness and optic nerve topography vary with race, axial length, and age in healthy children. Normative pediatric OCT data should facilitate the use of OCT in assessing childhood glaucoma and other diseases.

Distribution of Macular Thickness by Optical Coherence Tomography: Findings from a Population-Based Study of 6-Year-Old Children

To study the distribution of macular thickness by ocular and demographic variables in a population-based study of young children. The Sydney Childhood Eye Study examined 1765 6-year-old children from 34 randomly selected Sydney schools during 2003 and 2004 (78.9% response). A comprehensive eye examination included cycloplegic autorefraction and optical biometry. Fast macular thickness scans were performed over a 6-mm diameter central retinal region with optical coherence tomography. Multivariate analyses were performed. Macular thickness is presented on a modified Early Treatment Diabetic Retinopathy Study (ETDRS) macular grid, with outer radii for the central, inner, and outer macular regions being 0.5, 1.5, and 3 mm, respectively. In the study, 1543 children (88.7% of participants; 51.1% boys) had high-quality scan data (mean age, 6.7 years). The mean (SD) minimum foveal thickness was 161.1 (19.4) microm. The thickness of the central, inner, and outer macula was normally distributed, with means (SD) of 193.6 (17.9), 264.3 (15.2), and 236.9 (13.6) microm, respectively. Total macular volume was also normally distributed, with a mean (SD) of 6.9 (0.4) mm(3). The temporal quadrant was thinner than other quadrants for both inner and outer macular regions. The foveal minimum, central, and inner macula was generally significantly thicker in boys than in girls, and in white than in East Asian children. Outer macular thickness showed no significant gender-ethnic differences. Sectoral macular thickness variations were preserved in both gender and ethnic groups. The inner and outer macula, but not the central macula, showed significant thinning with increasing axial length. These corresponding areas were significantly thicker with more hyperopic spherical equivalent refractions. Macular thickness and volume were normally distributed in this young childhood population. Significant gender and ethnic differences were demonstrated. Axial length and refraction were important ocular biometric determinants of macular thickness.

Heritability of Macular Thickness Determined by Optical Coherence Tomography

To examine whether genetic factors significantly influence macular thickness in healthy older subjects. A classic twin study was performed to compare the correlation of macular thickness between monozygotic (MZ) and dizygotic (DZ) twins in a sample of population-based volunteer twins. The study included 109 white twin pairs from 50 to 80 years of age without evidence of manifest eye disease and corrected visual acuity better than 6/7.5. Dilated macular optical coherence tomography (OCT), fundus photography, clinical examination, ocular biometry, a health-dietary questionnaire, and subjective autorefraction were performed on all subjects. Correlation of retinal thickness was significantly greater between MZ twin pairs than DZ pairs in all macular regions. The MZ-to-DZ correlation was 0.88:0.44 for the foveal region, 0.79:0.47 for the inner macular region, and 0.81:0.50 for the outer macular region. With adjustment for significant covariates and model fitting, final heritability estimates of 85%, 81%, and 81%, respectively, were obtained. A significant correlation between foveal thickness and gender was present, with the men having significantly thicker foveae. There was a significant negative correlation between outer macular thickness and axial length. This study confirms that macular thickness in older healthy subjects, as measured by OCT, may be affected by genetic factors. Factors such as axial length, gender and age, warrant further examination in larger population-based studies, as variables that may influence macular thickness. This finding suggests an inherited basis of macular thickness and may help in the understanding of the factors that govern macular structure and function.

Evaluation of retinal nerve fiber layer, optic nerve head, and macular thickness measurements for glaucoma detection using optical coherence tomography

To compare the ability of optical coherence tomography retinal nerve fiber layer (RNFL), optic nerve head, and macular thickness parameters to differentiate between healthy eyes and eyes with glaucomatous visual field loss. Observational case-control study. Eighty-eight patients with glaucoma and 78 healthy subjects were included. All patients underwent ONH, RNFL thickness, and macular thickness scans with Stratus OCT during the same visit. ROC curves and sensitivities at fixed specificities were calculated for each parameter. A discriminant analysis was performed to develop a linear discriminant function designed to identify and combine the best parameters. This LDF was subsequently tested on an independent sample consisting of 63 eyes of 63 subjects (27 glaucomatous and 36 healthy individuals) from a different geographic area. No statistically significant difference was found between the areas under the ROC curves (AUC) for the RNFL thickness parameter with the largest AUC (inferior thickness, AUC = 0.91) and the ONH parameter with largest AUC (cup/disk area ratio, AUC = 0.88) (P = .28). The RNFL parameter inferior thickness had a significantly larger AUC than the macular thickness parameter with largest AUC (inferior outer macular thickness, AUC = 0.81) (P = .004). A combination of selected RNFL and ONH parameters resulted in the best classification function for glaucoma detection with an AUC of 0.97 when applied to the independent sample. RNFL and ONH measurements had the best discriminating performance among the several Stratus OCT parameters. A combination of ONH and RNFL parameters improved the diagnostic accuracy for glaucoma detection using this instrument.