Ana Sanchez-Cano

Choroidal Thickness and Volume in Healthy Young White Adults and the Relationships between them and Axial Length, Ammetropy and Sex

PURPOSE To evaluate choroidal thickness in young adults using enhanced-depth imaging spectral-domain optical coherence tomography and to describe volume differences in all the areas defined in the Early Treatment Diabetic Retinopathy Study. DESIGN Prospective clinical study. METHODS In 95 healthy young (23.8 ± 3.2 years) adult volunteers, 95 eyes were prospectively enrolled. Manual choroidal segmentation on a 25-raster horizontal scan protocol was performed. The measurements of the 9 subfields defined by the Early Treatment Diabetic Retinopathy Study were evaluated. RESULTS Mean subfoveal choroidal thickness was 345.67 ± 81.80 μm and mean total choroidal volume was 8.99 ± 1.88 mm(3). Choroidal thickness and volume were higher in the superior and temporal areas than in the inferior and nasal sectors of the same diameter, respectively. Strong correlations between subfoveal choroidal thickness and axial length and myopic refractive error were obtained (r = -0.649, P < 0.001, and r = 0.473, P < 0.001, respectively). Emmetropic eyes tended to have thicker subfoveal choroidal thickness (381.94 ± 79.88 μm vs 307.04 ± 64.91 μm) and higher total choroidal volume than myopic eyes (9.80 ± 1.87 mm(3) vs 8.14 ± 1.48 mm(3)). The estimation of the variation in the subfoveal choroidal thickness in relationship to the axial length was -43.84 μm/mm. In the myopic group, the variation in the subfoveal choroidal thickness with the myopic refractive error was -10.45 μm per diopter. CONCLUSIONS This study establishes for the first time a normal database for choroidal thickness and volume in young adults. Axial length, and myopic ammetropy are highly associated with choroidal parameters in healthy subjects. Enhanced-depth imaging spectral-domain optical coherence tomography exhibited a high degree of intraobserver and interobserver repeatability.

Magnification characteristics of the Optical Coherence Tomograph STRATUS OCT 3000

Purpose:  To evaluate the magnification characteristics of an Optical Coherence Tomograph (STRATUS OCT 3000) used to measure optic disc size.

Correlation between SD-OCT, immunocytochemistry and functional findings in an animal model of retinal degeneration

Purpose: The P23H rhodopsin mutation is an autosomal dominant cause of retinitis pigmentosa (RP). The degeneration can be tracked using different anatomical and functional methods. In our case, we evaluated the anatomical changes using Spectral-Domain Optical Coherence Tomography (SD-OCT) and correlated the findings with retinal thickness values determined by immunocytochemistry.Methods: Pigmented rats heterozygous for the P23H mutation, with ages between P18 and P180 were studied. Function was assessed by means of optomotor testing and ERGs. Retinal thicknesses measurements, autofluorescence and fluorescein angiography were performed using Spectralis OCT. Retinas were studied by means of immunohistochemistry. Results: Between P30 and P180, visual acuity decreased from 0.500 to 0.182 cycles per degree (cyc/deg) and contrast sensitivity decreased from 54.56 to 2.98 for a spatial frequency of 0.089 cyc/deg. Only cone-driven b-wave responses reached developmental maturity. Flicker fusions were also comparable at P29 (42 Hz). Double flash-isolated rod-driven responses were already affected at P29. Photopic responses revealed deterioration after P29.A reduction in retinal thicknesses and morphological modifications were seen in OCT sections. Statistically significant differences were found in all evaluated thicknesses. Autofluorescence was seen in P23H rats as sparse dots. Immunocytochemistry showed a progressive decrease in the outer nuclear layer (ONL), and morphological changes. Although anatomical thickness measures were significantly lower than OCT values, there was a very strong correlation between the values measured by both techniques.Conclusions: In pigmented P23H rats, a progressive deterioration occurs in both retinal function and anatomy. Anatomical changes can be effectively evaluated using SD-OCT and immunocytochemistry, with a good correlation between their values, thus making SD-OCT an important tool for research in retinal degeneration.

The Effect of Phacoemulsification Cataract Surgery on Polarimetry and Tomography Measurements for Glaucoma Diagnosis

PurposeTo assess whether optical coherence tomography (OCT)Stratus 3000, confocal laser scanning ophthalmoscopy (HRT3), and scanning laser polarimetry (GDx-VCC) results show parameter differences between presurgery and postsurgery in patients with cataracts and suspected glaucoma. SettingGlaucoma Service in the Department of Ophthalmology at the Miguel Servet University Hospital, Zaragoza, Spain. MethodsForty-six eyes of 46 patients were enrolled in this cross-sectional study and examined with OCT, HRT3, and GDx-VCC before and after phacoemulsification. Differences between presurgery and postoperative measurements were calculated using nonparametric test. ResultsThe most significant difference between the study groups was in the OCT image quality; the signal-to-noise ratio improved from presurgery to postsurgery. All of the statistically significant sectors reflected measurements in the nasal region and the maximum superior and average nasal retinal nerve fiber layer (thickness (Smax/Navg). Almost all parameters of the HRT area remained unchanged after the surgery, but important differences were observed in cup depth, volume parameters, and image quality. The Glaucoma Progression Score feature may not be helpful in the presence of lens opacity. Temporal incision during the surgery affected most of the nasal GDx-VCC parameters and the image quality. ConclusionsOCT image quality was reduced preoperatively in the eyes with cataracts and retinal nerve fiber layer thickness in the nasal sectors was increased in these eyes postoperatively. Cup depth, volume parameters, Glaucoma Progression Score, and the image quality of HRT measurements were all influenced by cataract removal. In our study temporal incision during surgery affected the nasal parameters in GDx-VCC. Our results suggest that the examiner should consider obtaining a new baseline measurement after cataract surgery.

Reproducibility and repeatability of Cirrus and Spectralis Fourier-domain optical coherence tomography of healthy and epiretinal membrane eyes.

Purpose: To evaluate the accuracy and reproducibility of retinal thickness measurements in healthy and epiretinal membranes (ERM) eyes by Cirrus and Spectralis Fourier-domain optical coherence tomography devices. Methods: Eighty-seven ERM and 122 healthy subjects underwent 3 macular scans using both optical coherence tomography instruments. Mean thickness measurements in the nine Early Treatment Diabetic Retinopathy Study areas were compared, evaluating the repeatability and the relationship between devices. Results: Macular thickness increase was detected in ERM eyes for all optical coherence tomography parameters (P < 0.001). Mean foveal thickness was 423.5 ± 81.4 and 438.0 ± 54.2 &mgr;m for ERM eyes and 267.1 ± 20.2 and 277.5 ± 18.9 &mgr;m for healthy eyes using Cirrus and Spectralis, respectively. Macular average thickness in ERM eyes as determined by both optical coherence tomography was correlated (r = 0.812; P < 0.001) but significantly different (P = 0.044). In ERM eyes, measurements showed a mean of the coefficients of variation of 2.95%, 2.2%, and 1.01% using Cirrus, Spectralis, and Spectralis progression feature, respectively. Intraclass correlation coefficients were higher than 0.919 in all cases. Conclusion: Reproducibility of both Cirrus and Spectralis optical coherence tomography was high in healthy and ERM eyes. However, considerable differences were found between macular thickness measurements obtained by both devices despite the high correlation between them.

Preperimetric glaucoma assessment with scanning laser polarimetry (GDx VCC): analysis of retinal nerve fiber layer by sectors.

PurposeTo evaluate the capability of the GDx VCC nerve fiber analyzer to detect preperimetric glaucoma across 12 retinal nerve fiber layer (RNFL) peripapillary sectors. MethodsData were obtained in a cross-sectional, hospital clinic-based study; 699 eyes from 699 glaucoma suspects were enrolled in this protocol. All subjects underwent ophthalmologic examination, static automated perimetry [Humphrey 24-2 Swedish interactive threshold algorithm (SITA) Standard], optic nerve stereoscopic photographs, red-free digital RNFL photographs and GDx VCC examination. Group S included 283 normal eyes and 39 preperimetric glaucoma eyes with RNFL superior or diffuse defects in the fiber layer photographs. Group I included 324 normal subjects and 24 with preperimetric glaucoma eyes with RNFL inferior or diffuse defects in fiber layer photographs. ResultsMean values of the area under the curve (AUC) for receiver operating characteristic analysis for inferior average (Inf Avg), temporal-superior-nasal-inferior temporal average (TSNIT Avg), superior average (Sup Avg), and the nerve fiber indicator were significantly less in the eyes with RNFL defects than the control group compared with the AUC for thickness at hour 12 and at hour 6 calculated from the RNFL sector density. The AUC for receiver operating characteristic analysis of the new parameters improved by 12% with respect to the best GDx VCC standard values. ConclusionsOur results confirm that the 12 sector divisions of the GDx VCC have better diagnostic reliability in preperimetric glaucoma, and are able to improve the discrimination capability between normal and early damaged RNFLs.

Age-related changes in photosensitive melanopsin-expressing retinal ganglion cells correlate with circadian rhythm impairments in sighted and blind rats

ABSTRACT The melanopsin system consists of intrinsically photosensitive retinal ganglion cells containing the photopigment melanopsin (mRGCs). These mRGCs mediate several non-image-forming visual functions, including light entrainment of circadian rhythms. Here we evaluate age-related alterations of the melanopsin system and circadian rhythms in P23H line 1 (P23H-1) rats, a rodent model of retinitis pigmentosa (RP). In homozygous P23H-1 rats and wild-type control rats from the same genetic background (Sprague–Dawley), body temperature and locomotor activity were continuously monitored at 10-min intervals for 7 days, once every 4–5 weeks, between 2 and 24 months of age, using a telemetry transmitter. The distribution and number of mRGCs were assessed in control rats at 12, 18, and 24 months of age and in P23H-1 rats aged 12, 18, 24, and 30 months by immunostaining whole-mount retinas with antibodies against melanopsin. The mean density of mRGCs in control rats showed no significant variations when evaluated at 12 and 18 months of age, and fell by approximately 56% between 18 and 24 months of age. Meanwhile, a significant decrease in the mean number of mRGCs was found in 18-month-old P23H-1 rats as compared to 18-month-old control rats (81% decrease). Parametric and non-parametric analyses of the records showed a gradual age-dependent weakening of body temperature and locomotor activity circadian rhythms robustness in both control and P23H-1 rats from 2 to 24 months of age. However, body temperature and locomotor activity circadian patterns were less robust throughout the experiment in P23H-1 as compared to control rats, with lower amplitude, weaker coupling strength to environmental zeitgebers and higher fragmentation of the rhythms. The present study shows that the degeneration of photoreceptors and inner retinal neurons, characteristic of RP, has age-related degenerative effects on the melanopsin system and is associated with weaker circadian patterns.

Repeatability of ocular measurements with a dual-Scheimpflug analyzer in healthy eyes.

Purpose. To assess the repeatability of the Galilei dual Scheimpflug analyzer (GDSA) in anterior segment examination. Methods. Fifty-two eyes from 52 healthy volunteers were prospectively and consecutively recruited. Anatomic, axial, refractive, and instantaneous parameters were measured with GDSA to provide a complete characterization of the anterior segment. Repeatability was assessed calculating intraclass correlation coefficient (ICC), and coefficient of variation (COV). Results. Correlation among repeated measurements showed almost perfect reliability (ICC > 0.81) for all parameters except thinnest central corneal thickness (CCT) (0.78), corneal thickness average out (0.79), and posterior axial curvature average out (0.60). Repeatability was excellent (COV < 10%) for all parameters except anterior chamber volume and, superior iridocorneal angle and eccentricities. In these last three parameters, repeatability limits were excessively high compared to the mean. Conclusions. GDSA in healthy young persons had an almost perfect correlation in measuring anatomic, axial, instantaneous, and refractive parameters with greater variability for peripheral terms. Repeatability of anatomical parameters like pachymetry, anterior chamber, or iridocorneal angle and eccentricity were limited. In healthy young persons, the other evaluated parameters had very good repeatability and their limits of agreement showed excellent clinical results for this device.

CHOROIDAL THICKNESS AND VOLUME IN A HEALTHY PEDIATRIC POPULATION AND ITS RELATIONSHIP WITH AGE, AXIAL LENGTH, AMETROPIA, AND SEX.

Purpose: To evaluate choroidal thickness (CT) and volume in healthy pediatric individuals using enhanced depth imaging spectral domain optical coherence tomography (SD-OCT), as well as its association with age, sex, axial length (AL), and refractive error. Methods: Ninety-three eyes from 93 healthy pediatric individuals were examined. An Early Treatment Diabetic Retinopathy Study grid was applied to analyze CT and volume map in each of its nine sectors. Results: The mean subfoveal CT and volume were 314.22 ± 55.48 &mgr;m and 0.25 ± 0.04 mm3, respectively. The nasal CT and volume of both the inner and the outer rings were significantly lower than the temporal area of the same ring and lower than the subfoveal choroidal thickness. A significant negative correlation between the subfoveal CT and AL (r = −0.250, P = 0.015) and a significant positive correlation between the subfoveal CT and refractive error (r = 0.238, P = 0.006) were found. The estimation of the variation in the subfoveal CT in relationship to the AL was −13.55 &mgr;m per millimeter. The variation in the subfoveal CT with refractive error was 7.52 &mgr;m per diopter. The estimation of the variation in the total choroidal volume related to the AL and ametropia was, respectively, −0.2354 mm3 per millimeter and 0.1412 mm3 per diopter. Conclusion: Healthy pediatric subjects exhibit choroidal differences in refractive error and AL. In the study population, CT and volume show an increase with age after adjusting for AL.

Comparison of Anterior Segment Measurements Obtained by Three Different Devices in Healthy Eyes

Purpose. To assess the normal values and the repeatability of the Galilei Dual Scheimpflug Analyzer (GDSA), the biometer IOL Master, and the autokerato/refractometer WAM 5500 in anterior segment examinations. Methods. Eighty-eight eyes from 88 healthy volunteers were prospectively and consecutively recruited. The repeatability was assessed, calculating the intraclass correlation coefficient (ICC). Results. The correlations among the repeated measurements showed nearly perfect reliability (ICC > 0.81) for all of the parameters, except corneal astigmatism Galilei (0.79) and WAM (0.68). There were statistically significant differences (P < 0.001) between the values of the flat simulated keratometry (SimK) and the steep SimK measured by GDSA and the other methods; however, there were no statistically significant differences for the values obtained with the IOL Master and WAM 5500 (P = 0.302 and P = 0.172, resp.) or between the values of the ACD (P < 0.001) and WTW (P = 0.007) measured by the IOL Master and GDSA. Conclusions. The anterior segment measurements from the IOL Master and WAM 5500 were highly repeatable, comparable, and well correlated. In healthy young persons, the evaluated parameters had very good repeatability, although significant differences were found between the GDSA and IOL Master and between the GDSA and WAM 5500.