Macula and optic disk features in methamphetamine and crystal methamphetamine addicts using optical coherence tomography.

PURPOSE: Methamphetamine and crystal methamphetamine abusers were compared with healthy subjects using optical coherence tomography to assess their retinal nerve fiber layer, macula, and optic disk characteristics. METHODS: Forty-one methamphetamine and crystal methamphetamine abusers and 42 healthy subjects (mean ± SD of age: 35.82 ± 8.6 and 37.76 ± 9.1 years, respectively) were incorporated in this cross-sectional study. The drug abusers had a history of at least five years of substance use through smoking. Fourier-domain optical coherence tomography was used to image and assess the characteristics of retinal nerve fiber layer, macular thickness, and optic disk in the study groups. RESULTS: The retinal nerve fiber layer thickness was significantly lower in the superior and temporal retinal quadrants of drug abusers than healthy subjects (P = 0.008 and P = 0.028, respectively). This study did not find a significant difference between drug abusers and healthy controls regarding optic to disk ratio, rim area, and disk area (P > 0.05). The comparison between the study groups showed that the reductions in perifovea and the superior quadrant of parafoveal thickness were statistically significant (P < 0.001 and P = 0.029, respectively). CONCLUSION: Fourier-domain optical coherence tomography measurements showed that the retinal nerve fiber layer and macular thickness were different between methamphetamine and crystal methamphetamine abusers and healthy subjects, which should be considered in clinical practice. It seems that these drug abuses can cause alterations in retinal morphology.

Grado de concordancia y diferencias entre valores maculares en niños mediante dos tipos de tomografía de coherencia óptica espectral / Agreement and differences between macular values in children using two types of spectral optical coherence tomography

Objetivo Determinar el grado de concordancia y las diferencias entre los parámetros maculares en función de sexo, edad, lateralidad, etnia y tipo de tomografía de coherencia óptica (OCT) en pacientes pediátricos. Materiales y métodos Estudio prospectivo, transversal y comparativo. Se hizo uso de la OCT Spectralis y la OCT Cirrus para obtener los valores maculares de ambos ojos en 100 pacientes entre 5 y 15años sin patología ocular. Debido a la semejanza entre los valores de ambos ojos, en la muestra final solo consideramos los ojos derechos (OD) (n=100). Resultados La media del grosor macular central (GMC) fue de 244,2μm con Cirrus y 261,7μm con Spectralis. El grado de concordancia para el GMC fue moderado (coeficiente de correlación intraclase: 0,66) y de bajo a muy bajo en el resto de cuadrantes. Los valores de GMC de ambos sistemas fueron significativamente mayores en varones que en mujeres (p<0,05). La capa de fibras nerviosas de la retina macular (CFNRm), la capa de células ganglionares (CCG), la capa plexiforme interna (CPI) y la capa nuclear interna (CNI) tuvieron valores significativamente mayores en varones que en mujeres (p<0,01). No hubo diferencias estadísticamente significativas en el GMC según edad y lateralidad; sin embargo, fue significativamente mayor en niños de etnia europea que en niños de etnia latinoamericana; Cirrus (p=0,042) y Spectralis (p=0,033). Conclusiones Los parámetros maculares obtenidos mediante OCT Spectralis y OCT Cirrus no deberían ser intercambiables en pacientes pediátricos (AU)

Objective To determine the degree of agreement and differences between macular parameters according to sex, age, laterality, ethnicity and type of optical coherence tomography (OCT) in paediatric patients. Materials and methods Prospective, transversal, and comparative study. OCT Spectralis and OCT Cirrus were used to obtain the macular values of both eyes in 100 patients between 5 and 15years without ocular pathology. Due to the similarity between the values of both eyes, in the final sample we only considered the right eyes (OD) (n=100). Results The average central macular thickness (CMT) was 244.2μm with Cirrus and 261.7μm with Spectralis. The degree of agreement for the GMC was moderate (intraclass correlation coefficient: 0.66) and from low to very low in the other quadrants. The GMC values of both systems were significantly higher in men than in women (P<.05). The macular retinal nerve fibre layer (mRNC), ganglion cell layer (GCC), the inner plexiform layer (IPLC), and the inner nuclear layer (INFL) had significantly higher values in men than in women (P<.01). There were no statistically significant differences in the GMC by age and laterality, however it was significantly higher in ethnic European children than in ethnic Latin American children; Cirrus (P=.042) and Spectralis (P=.033). Conclusions Macular parameters obtained by OCT Spectralis and OCT Cirrus should not be interchangeable in pediatric patients (AU)

Heritability of macular ganglion cell inner plexiform layer thickness as determined by optical coherence tomography: the Healthy Twin Study.

PURPOSE: To evaluate genetic influence on macular ganglion cell inner plexiform layer (GCIPL) thickness. METHODS: Macular GCIPL thickness was measured with optical coherence tomography in nine macular subfields defined by the E TDRS. Intraclass correlation coefficients (ICC) of GCIPL thickness by different types of family relationships were estimated to assess intrafamilial resemblance. Then, heritability of GCIPL thickness was estimated. RESULTS: Three hundred and sixty-one Korean adults from 89 families with normal healthy eyes were included. GCIPL thickness was highest in inner subfields and lowest in fovea. Monozygotic twin pairs showed significantly higher ICCs of GCIPL thickness in all subfields compared to those in parent-offspring pairs and sibling pairs. GCIPL thickness was highly heritable in the centre (0.71) and outer subfields but moderate to highly heritable in inner subfields. Heritability of GCIPL thickness in outer subfields was 0.69, 0.67, 0.72 and 0.68 for superior, inferior, temporal and nasal fields, respectively. Heritability of GCIPL thickness in inner subfields was 0.55, 0.56, 0.75 and 050 for superior, inferior, temporal and nasal subfields, respectively. CONCLUSION: Macular GCIPL thickness is significantly influenced by genetic factors. It varies according to subfields with moderate to high heritability in all subfields.

Normal Reference Ranges of Optical Coherence Tomography Parameters in Children.

AIM: To measure the macular thickness, macular volume and peripapillary retinal nerve fiber layer (RNFL) in healthy Caucasian chil-dren using spectral domain optical coherence tomography (SDOCT) and analyze the correlation of these values with age, refraction, and biometric measurements. MATERIALS AND METHODS: In this cross-sectional study, we recruited 270 healthy children (150 female and 120 male) aged 6 to 17 years with no ocular abnormalities. All children underwent a detailed eye examination. The measurements were obtained using a SDOCT device (SOCT Copernicus REVO). Main outcome measures were macular thickness, macular volume and RNFL thickness. Their correlations with age, refractive error, anterior chamber depth (ACD) and axial length (AL) was analyzed. Right eyes of all subjects were selected for analysis. RESULTS: In this study group (mean age 10.70±2.82 years), the average peripapillary RNFL thickness was 117.11±9.15 µm, the central macular thickness was 232.10±15.81 µm, the average macular thickness was 286.70±9.82 µm, and the average macular volume was 8.01±0.28 mm³. The average values for the biometric data were: axial length - 23.16±0.94 mm, anterior chamber depth - 3.64±0.26 mm, the spherical equivalent (SE) value - +0.81±0.58 diopter. Central macular thickness, inner macular thickness (superior, inferior, nasal, temporal quadrants) values, total macular thickness and macular volume were significantly higher in males than in females. We found a positive correlation between central macular thickness, inner nasal macular thickness, outer inferior macular thickness values, and age. Also, we found a significant correlation between the average macular thickness values and the average macular volume values (p<0.0001). RNFL measurements did not correlate with age (p=0.199). Almost all macular parameters were consistently positively cor-related with SE. A significant correlation was also found between the central macular thickness, inner inferior macular thickness, inner nasal macular thickness and the ACD. We found a significant correlation between the average macular thickness, macular volume, inner superior macular thickness, outer macular thickness (superior, inferior, nasal, temporal quadrants) values and the AL. CONCLUSION: This study found normal reference ranges for RNFL and macular parameters measured by SOCT Copernicus REVO in healthy Caucasian children aged 6-17 years. This normative values could be very useful in early diagnosing and monitoring of optic neuropathy, glaucoma and macular diseases in childhood.

Association between Macular Thickness Profiles and Visual Function in Healthy Eyes: The Singapore Epidemiology of Eye Diseases (SEED) Study.

This study aimed to evaluate the association between optical coherence tomography (OCT)-measured retinal layer thickness parameters with clinical and patient-centred visual outcomes in healthy eyes. Participants aged 40 and above were recruited from the Singapore Epidemiology of Eye Diseases Study, a multi-ethnic population-based study. Average macular, ganglion cell-inner plexiform layer (GCIPL), and outer retinal thickness parameters were obtained using the Cirrus High Definition-OCT. Measurements of best-corrected visual acuity (BCVA) and 11-item visual functioning questionnaire (VF-11) were performed. Associations between macular thickness parameters, with BCVA and Rasch-transformed VF-11 scores (in logits) were assessed using multivariable linear regression models with generalized estimating equations, adjusted for relevant confounders. 4,540 subjects (7,744 eyes) with a mean age of 58.8 ± 8.6 years were included. The mean BCVA (LogMAR) was 0.10 ± 0.11 and mean VF-11 score was 5.20 ± 1.29. In multivariable regression analysis, thicker macula (per 20 µm; ß = -0.009) and GCIPL (per 20 µm; ß = -0.031) were associated with better BCVA (all p ≤ 0.001), while thicker macula (per 20 µm; ß = 0.04) and GCIPL (per 20 µm, ß = 0.05) were significantly associated with higher VF-11 scores (all p < 0.05). In conclusion, among healthy Asian eyes, thicker macula and GCIPL were associated with better vision and self-reported visual functioning. These findings provide further understanding on the potential influence of macular thickness on visual function.

Normative values of the retinal macular thickness in a middle eastern population.

BACKGROUND: Since the normative value of the retinal macular thickness is undocumented in the Middle East, the aim of this work is to assess the normative values of the macular thickness in healthy eyes in a Middle Eastern population and its relationship with age, sex, and laterality. METHODS: One hundred sixteen individuals were randomly selected from volunteers visiting the Jordan University Hospital in Amman, Jordan. Measurements were obtained using the Fourier domain optical coherence tomography (OCT). Multivariate regression models were developed to obtain predicted normative values with adjustment to candidate variables. In addition, the effect of age, sex and laterality were evaluated. RESULTS: The average central fovea macular thickness was 229.5 (±30.85) um. The quadratic value of the retinal macular thickness decreased from the superior value of 299.71 (±23.67) um (P = .001) to the inferior value of 296.46 (±28.85) um(P = .001) and a nasal figure of 93.63 (±26.86) um(P = .001). The temporal area has the thinnest value of 293.43 (±30.78) um (P = 0.001). Central thickness was higher in males with a mean variation of 11.67 um (95% CI, 2.41 to 20.93) (p = 0.003). The thickness was highest within 3 mm diameter from the center and decreased towards the periphery Eye sidedness didn't contribute to variability of the macular thickness. Furthermore, we found a significant difference between age and central macular thickness (p = 0.001), as age was a positive predictor for macular thickness. CONCLUSION: Our set of predicted normative data may be used to interrupt measurement of the macular thickness in Middle Eastern population. The average fovea macular thickness among Jordanians is consistent with previously reported values. Normative values from additional Middle Eastern. Population are required to appraise our model.

Genetic influence on macular retinal nerve fibre layer thickness according to retinal subfield.

BACKGROUND/AIM: Characterising genetic effect on macular retinal nerve fibre layer (RNFL) is needed to obtain better understanding of various retinopathies and optic neuropathies. The purpose of this study was to evaluate genetic influence on macular RNFL thickness. METHODS: This is a cross-sectional, twin and family study. Three hundred and sixty-two Korean adults with healthy eyes were included in the study from 79 households with two or more family members. Macular RNFL thickness was measured with optical coherence tomography at nine macular subfields defined by the ETDRS. Intraclass correlation coefficients (ICCs) were estimated to assess intrafamilial resemblance of RNFL thickness by different types of family relationship. Heritability of RNFL thickness was evaluated using variance decomposition model. RESULTS: RNFL thickness increased from central subfield to outer subfields. Temporal quadrant RNFL was thinner compared with other quadrants. Monozygotic twin pairs showed the highest ICCs of RNFL thickness, although the ICC level varied across different subfields. Heritability of RNFL thickness was the highest at central subfield (0.81). RNFL thicknesses of outer subfields were moderately to highly heritable: 0.53, 0.71, 0.47 and 0.66 for superior, inferior, temporal and nasal fields, respectively. RNFL thicknesses at inner subfields showed the lowest heritability: 0.21, 0.24, 0.27 and 0.27 for superior, inferior, temporal and nasal subfields, respectively. CONCLUSION: Macular RNFL thickness is significantly influenced by genetic factors. It varies largely by subfields with the highest heritability at the central subfield and a relatively lower heritability at inner subfields.

Comparison of Individual Retinal Layer Thicknesses between Highly Myopic Eyes and Normal Control Eyes Using Retinal Layer Segmentation Analysis.

The incidence of myopia is increasing worldwide, and the investigation on pathophysiology of myopia is becoming more important. This retrospective study aimed to compare the thicknesses of individual retinal layers between high-myopic and control eyes, and to evaluate the effects of age and sex on each retinal layer thickness. We assessed 164 subjects and divided them into two groups based on axial length (AL) (i.e., high-myopic group (AL ≥ 26 mm) and control group (AL < 26 mm)). Individual retinal layer thicknesses of five subfields in the macula were measured using automated retinal segmentation software packaged with the spectral-domain optical coherence tomography and were compared. In high-myopia group, the thicknesses of total retina and all individual retinal layers in central and entire perifoveal subfields were significantly thicker than the corresponding layers in control group after adjustment for ocular magnification (all P < 0.05). There were no significant effects of sex on individual retinal thicknesses, and age had less negative effects on the thicknesses of retina layers in high-myopic eyes than normal eyes. Axially elongated, non-pathologic highly myopic eyes had different structural features than control eyes, with significantly greater individual macular layer thicknesses independent of sex or age.

Myopia: Anatomic Changes and Consequences for Its Etiology.

The process of emmetropization is the adjustment of the length of the optical axis to the given optical properties of the cornea and lens after the end of the second year of life. Up to the end of the second year of life, the eye grows spherically. Axial elongation in the process of emmetropization after the second year of life is associated with a thinning of the retina and a reduced density of retinal pigment epithelium (RPE) cells in the equatorial and retroequatorial region, and a thinning of the choroid and sclera, starting at the equator and being most marked at the posterior pole. In contrast, retinal thickness and RPE density in the macular region and thickness of Bruch membrane (BM) in any region are independent of axial length. It led to the hypothesis that axial elongation occurs by the production of additional BM in the equatorial and retroequatorial region leading to a decreased RPE density and retinal thinning in that region and a more tube-like than spherical enlargement of the globe, without compromise in the density of the macular RPE cells and in macular retinal thickness. The increased disc-fovea distance in axially myopic eyes is caused by the development and enlargement of parapapillary, BM-free, gamma zone, whereas the length of macular BM, and indirectly macular RPE cell density, and macular retinal thickness, remain constant.

Peripapillary and macular choroidal thickness before and after phenylephrine instillation.

OBJECTIVES: We investigated the effects of topical phenylephrine 2.5% instillation on choroidal thickness (CT), peripapillary choroidal thickness (pCT) and retinal nerve fibre layer (RNFL). METHODS: Healthy control patients underwent enhanced depth imaging (EDI) by spectral-domain optical coherence tomography (OCT) before and 30 min after phenylephrine instillation, using eye-tracking and follow-up software. Changes in 14 different locations of CT, 2 locations of pCT and RNFL were assessed. RESULTS: The study included 119 eyes of 62 patients (19 males and 43 females), with a mean age of 59.8 ± 15.3 years (range: 26-88 years). Within 30 min after instillation, the mean subfoveal CT both in vertical and horizontal scan were significantly thinned (p = 0.005 and p = 0.018, respectively). In total, 1500, 1000 and 500 µm temporal CT measurements showed also a significant thinning (p = 0.021, p = 0.037 and p = 0.020, respectively), as well as 500 µm both superior (p = 0.045) and inferior (p = 0.009). 1500, 1000 and 500 µm nasal CT, and 1500 and 1000 µm CT superior and inferior measurements showed no significant thinning after phenylephrine instillation. pCT was significantly thinned after phenylephrine in both superior (p = 0.016) and inferior (p = 0.050) measurements. RNFL analysis did not significantly change after phenylephrine instillation (p = 0.209). CONCLUSIONS: A significant thinning of CT and pCT occurred following phenylephrine instillation. Future studies analysing CT and pCT should detail if this mydriatic agent was used or not.

Macular retinal thickness and flow density change by optical coherence tomography angiography after posterior scleral reinforcement.

Optical coherence tomography angiography (Angio-OCT) has introduced a new non-invasive, quantitative method to assess superficial and deep capillary networks of the retina. In this study, we investigated macular retinal thickness and flow density change following posterior scleral reinforcement (PSR) surgery, using an RTVue XR Avanti Angio-OCT (A2016.2.0.35, Optovue, Fremont, CA), in patients with pathological myopia. A total of 13 patients with pathological myopia were recruited and all patients completed the 6 months follow-up visit. Data from 22 eyes were used in this study. The mean age was 36.23±15.29 years, and 43% (n=6) were men. Spherical equivalent refractive error (SE) ranged from -8.0 to -24.0 D. Post-operative axial length, best-corrected visual acuity and SE did not change significantly at each follow-up, compared with preoperative measure (all P>0.05). Postoperative flow density of superficial and deep retinal layers at each sector did not change significantly at each follow-up, compared to pre-operative measure (all P>0.05). However, we found significant decrease in retinal thickness of parafovea-inferior sector after PSR surgery (P<0.01), indicating potential relaxation of vitreofoveal traction after PSR surgery.

Cohort profile: design and methods in the eye and vision consortium of UK Biobank.

PURPOSE: To describe the rationale, methods and research potential of eye and vision measures available in UK Biobank. PARTICIPANTS: UK Biobank is a large, multisite, prospective cohort study. Extensive lifestyle and health questionnaires, a range of physical measures and collection of biological specimens are collected. The scope of UK Biobank was extended midway through data collection to include assessments of other measures of health, including eyes and vision. The eye assessment at baseline included questionnaires detailing past ophthalmic and family history, measurement of visual acuity, refractive error and keratometry, intraocular pressure (IOP), corneal biomechanics, spectral domain optical coherence tomography (OCT) of the macula and a disc-macula fundus photograph. Since recruitment, UK Biobank has collected accelerometer data and begun multimodal imaging data (including brain, heart and abdominal MRI) in 100 000 participants. Dense genotypic data and a panel of 20 biochemistry measures are available, and linkage to medical health records for the full cohort has begun. FINDINGS TO DATE: A total of 502 665 people aged between 40 and 69 were recruited to participate in UK Biobank. Of these, 117 175 took part in baseline assessment of vision, IOP, refraction and keratometry. A subgroup of 67 321 underwent OCT and retinal photography. The introduction of eye and vision measures in UK Biobank was accompanied by intensive training, support and a data monitoring quality control process. FUTURE PLANS: UK Biobank is one of the largest prospective cohorts worldwide with extensive data on ophthalmic diseases and conditions. Data collection is an ongoing process and a repeat of the baseline assessment including the questionnaires, measurements and sample collection will be performed in subsets of 25 000 participants every 2-3 years. The depth and breadth of this dataset, coupled with its open-access policy, will create a powerful resource for all researchers to investigate the eye diseases in later life.

Macular Thickness and Mesopic Visual Acuity in Healthy Older Subjects.

Purpose/Aim: Impaired mesopic visual acuity (VA) is a risk factor for incident early age-related macular degeneration (AMD) This study examines relationships between macular thickness measurements and photopic or mesopic VA in healthy eyes. MATERIALS AND METHODS: In 38 young and 39 older healthy individuals, total, inner, and outer retinal layer (IRL and ORL) thicknesses were measured in the macula region through spectral-domain optical coherence tomography (SD-OCT). Measurements were made across three subfields centered at the fovea: central foveal, pericentral, and peripheral. Best-corrected distance high-contrast (HC) and low-contrast (LC) VA were measured using Bailey-Lovie logMAR letter charts under photopic and mesopic luminance conditions. In addition, the low luminance deficit in VA (LLD, difference between photopic and mesopic VA) was calculated. Relationships were examined through Spearman correlation in each age group and through multiple linear regressions across all eyes. RESULTS: No significant correlations were detected between photopic VA (HC-VA and LC-VA) and macular thickness measurements in each age group. In mesopic conditions, age and pupil size were independent predictors of HC-VA (p = 0.001) and age and pericentral ORL thickness predictors of LC-VA (p = 0.001). Central foveal thickness emerged as the unique independent predictor of LLD (HC-VA, p = 0.013 and LC-VA, p = 0.005). Only in the older age group, was central foveal thicknesses correlated with LLD (HC-VA, r = + 0.45; p = 0.004 and LC-VA, r = + 0.33, p = 0.038). CONCLUSIONS: Greater macular thicknesses were related to worse mesopic VA and low luminance deficit in healthy subjects.

Macular thickness and retinal nerve fiber thickness analysis in ocular dominance / Espessura macular e fibra nervosa da retina análise de espessura no domínio ocular

Abstract Objective: To compare macular and peripapillary retinal nerve fiber layer thicknesses of dominant eye and non-dominant eye using optical coherence tomography (OCT). Methods: 104 eyes of 52 healthy young adults were included. Ophthalmological examinations; including measuring refraction, best corrected visual acuity, intraocular pressure (IOP) measurement, slit-lamb biomicroscopy, dilated fundus examination, measuring of central macular thickness (CMT), and peripapillary retinal nerve fiber layer (PRNFL) thickness were performed on each subject. Hole-in-the-card test was used to detect the ocular dominance. Results: There were 25 females (48%) and 27 males (52%) in the study. Eight participants had left eye dominance (15%), forty-four participants had right eye dominance (85%). Mean CMT was 192.5µm in dominant group and 191.9 µm in non-dominant group. There was no statistically significant difference between dominant eye group and non-dominant eye group in either macular thickness or peripapillary retinal nerve fiber layer thickness. Conclusions: No difference between macular and peripapillary retinal nerve fiber layer thicknesses were detected in dominant and non-dominant groups. Further evaluation is needed.

Resumo Objetivo: Comparar as espessuras da camada de fibras nervosas da retina macular e peripapilar do olho dominante e não dominante usando a tomografia de coerência óptica (OCT). Métodos: 104 olhos de 52 adultos jovens saudáveis foram incluídos. Exames oftalmológicos; incluindo medidas de refração, melhor acuidade visual corrigida, medição da pressão intraocular (PIO), biomicroscopia de fenda-cordeiro, exame do fundo dilatado, medição da espessura macular central (CMT) e espessura da camada de fibras nervosas da retina peripapilar (PRNFL) foram realizadas em cada sujeito. O teste Hole-in-the-card foi usado para detectar a dominância ocular. Resultados: houve 25 mulheres (48%) e 27 homens (52%) no estudo. Oito participantes tinham deixado a dominância do olho (15%), quarenta e quatro participantes tinham dominância do olho direito (85%). A CMT média foi de 192,5 µm no grupo dominante e 191,9 µm no grupo não dominante. Não houve diferença estatisticamente significativa entre o grupo dominante de olho e o grupo de olho não dominante tanto na espessura macular quanto na espessura da camada de fibras nervosas da retina peripapilar. Conclusões: Não houve diferença entre as espessuras das camadas de fibras nervosas da retina macular e peripapilar nos grupos dominante e não dominante. Mais avaliações são necessárias.

Macular Inner Retinal Layer Thickness in Relation to Photopic and Mesopic Contrast Sensitivity in Healthy Young and Older Subjects.

Purpose: To examine relationships between the thicknesses of ganglion cell (GC)-related macular layers and central photopic or mesopic contrast sensitivity (CS) in healthy eyes. Methods: Measurements were made in 38 young and 38 older healthy individuals. Total, inner, and outer retinal layer (IRL) thicknesses were measured in the macula region through spectral-domain optical coherence tomography (SD-OCT) across three subfields, or rings, centered at the fovea: central foveal, pericentral, and peripheral. Ganglion cell complex and circumpapillary retinal nerve fiber layer thicknesses were also measured. Low-spatial-frequency CS for gratings presented at the central 10° visual field were measured through computerized psychophysical tests under photopic and mesopic conditions. Relationships were examined by uni- and multivariate regression analysis. Results: Peripheral IRL thickness emerged as the only independent predictor of photopic CS (P = 0.001) in the young group and of photopic (P = 0.026) and mesopic CS (P = 0.001) in the older group. The slopes of regression lines used to predict CS from peripheral IRL thickness were significantly different for pair-wise comparisons of both photopic CS and age group (P = 0.0001) and mesopic CS (P = 0.0001) and age group. These models explained 37% of the variability in photopic CS and 36% of the variability in mesopic CS. Conclusions: Macular IRL thinning likely due to GC loss was related to reduced photopic and mesopic CS in older healthy eyes. In contrast, in the young eyes, a thicker macular IRL, possibly indicating transient gliosis, was associated with reduced CS.

The Fovea-BMO Axis Angle and Macular Thickness Vertical Asymmetry Across The Temporal Raphe.

PURPOSE: To test the hypothesis that the fovea-Bruch's membrane opening (FoBMO) axis angle influences the thickness symmetry of the macular ganglion cell/inner plexiform layer (GCIPL) across the temporal horizontal meridian in normal subjects. DESIGN: Cross-sectional diagnostic study at a tertiary academic center. METHODS: One hundred sixteen eyes of 60 normal subjects aged 40 to 85 years underwent spectral domain optical coherence tomography(SD-OCT) imaging. The FoBMO angle was estimated on en face infrared SD-OCT images. Posterior Pole algorithm images acquired with Spectralis SD-OCT were used to define vertical asymmetry as follows. The average thickness difference between the 3 most temporal superpixels above and below the horizontal meridian, the second row of superpixels from the horizontal meridian, and 3 central superpixels above and below the horizontal meridian were calculated. Factors influencing GCIPL thickness asymmetry were explored and changes in thickness asymmetry as a function of FoBMO angle were investigated. RESULTS: No demographic or clinical factors affected temporal GCIPL asymmetry (P>0.05 for all). A more (negatively) tilted FoBMO angle was associated with relatively thinner inferior compared with superior GCIPL thickness in superpixels immediately adjacent to the temporal raphe (P<0.001). The second row of temporal superpixels from the horizontal meridian (P=0.349) or central superpixels (P=0.292) did not show this tendency. CONCLUSIONS: Vertical GCIPL symmetry across the horizontal meridian is influenced by the FoBMO angle. SD-OCT algorithms using vertical asymmetry as a diagnostic index should be adjusted for the FoBMO angle.

Comparison of optic disk features in preterm and term infants.

PURPOSE: To compare the optic disk features of preterm and term infants. METHODS: Digital fundus images of preterm infants were compared with those of infants born at term, imaged within 1 week of birth. The optic disk horizontal diameter to vertical diameter ratio, the disk-macula to disk-diameter ratio, and the presence or absence of double ring sign was noted. RESULTS: Images of 649 infants (324 preterm and 325 term) were analyzed. Of the preterm infants, 129 (40%) had a double ring sign, compared to 4% in term infants. The double ring was seen more frequently in infants of European descent and was more common with younger gestational age. The mean horizontal to vertical disk diameter in preterm infants on first examination was 0.75 ± 0.063, increasing to 0.80 ± 0.069 at final examination. Term infants had a horizontal to vertical disk diameter ratio of 0.79 ± 0.064. At final examination, the ratio of disk-to-macula distance to the horizontal disk diameter was 3.9 in preterm infants and 3.7 for term infants. CONCLUSIONS: In our study population preterm infants often had a double ring sign around the optic disk in the absence of optic nerve hypoplasia. Preterm disks tend to be more vertically oval, which becomes less oval closer to term. The mean disk-to-macula to disk-diameter ratio among normal preterm infants was higher than previously reported.

The effect of fish consumption on macula structure and function of healthy individuals: an OCT and mfERG study.

OBJECTIVE: The study was designed to investigate the potential effect of fish consumption on macular structure and function of healthy individuals. PATIENTS AND METHODS: The participants were Greek, who used to consume less than one portion of fish per week since their childhood. All participants underwent body mass index (BMI) measurements and ophthalmological examination. At their first examination, they were asked to consume at least 2 portions of fish per week over a period of 8 weeks, after which all the measurements were repeated. RESULTS: Eighteen healthy individuals (36 eyes) participated in this study. The central macular thickness was reduced, while the amplitudes in the foveal and parafoveal area were increased after the fish consumption. However, all measurements remained within the normal range at both visits. CONCLUSIONS: Regular fish consumption could enhance the structural and functional status of the macula.

Effects of age and gender on macular thickness in healthy subjects using spectral optical coherence tomography/scanning laser ophthalmoscopy.

PURPOSE: To examine healthy subjects for normal macular thickness values and determine the effects of gender and age in a Turkish population, using spectral optical coherence tomography/scanning laser ophthalmoscopy (OCT/SLO). MATERIAL AND METHOD: Six hundred fourteen eyes of 307 subjects with no history of ocular diseases and normal ophthalmic examination were recruited in this cross-sectional, prospective study. The participants were divided into three groups based on age (between 20 and 29 years: group 1, between 30 and 39 years: group 2, between 40 and 49 years: group 3). All subjects were scanned with spectral OCT/SLO, performed by one examiner to acquire the retinal thickness map in the ETDRS grid, and values were recorded for nine sectors, and effects of age and gender were evaluated. RESULTS: When all the subjects were evaluated, the thicknesses were lower in women than men in all sectors (p < 0.001). When divided in groups based on age, this difference remained only in the outer segments. However, the differences in outer layers, except outer nasal layer, were thicker in women in group 3 when compared to others in group 3. When compared between groups, only central thickness in group 3 was shown to be higher than group 1 (p = 0.06). There was no significant difference of thicknesses in any sector when compared right and left eyes of all subjects. CONCLUSIONS: The study reports the variation in retinal thickness between age and gender in a relatively large sample of a Turkish population. It is important to consider these effects while interpreting the OCT images to make an appropriate diagnosis in retinal diseases.

Intensity inhomogeneity correction of SD-OCT data using macular flatspace.

Images of the retina acquired using optical coherence tomography (OCT) often suffer from intensity inhomogeneity problems that degrade both the quality of the images and the performance of automated algorithms utilized to measure structural changes. This intensity variation has many causes, including off-axis acquisition, signal attenuation, multi-frame averaging, and vignetting, making it difficult to correct the data in a fundamental way. This paper presents a method for inhomogeneity correction by acting to reduce the variability of intensities within each layer. In particular, the N3 algorithm, which is popular in neuroimage analysis, is adapted to work for OCT data. N3 works by sharpening the intensity histogram, which reduces the variation of intensities within different classes. To apply it here, the data are first converted to a standardized space called macular flat space (MFS). MFS allows the intensities within each layer to be more easily normalized by removing the natural curvature of the retina. N3 is then run on the MFS data using a modified smoothing model, which improves the efficiency of the original algorithm. We show that our method more accurately corrects gain fields on synthetic OCT data when compared to running N3 on non-flattened data. It also reduces the overall variability of the intensities within each layer, without sacrificing contrast between layers, and improves the performance of registration between OCT images.