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Purpose: To observe the photoreceptor anomalies in cases of ametropic amblyopia. Methods: A prospective study with 25 isoametropic amblyopic children in the age group of 5–14 years and 25 age?matched controls was done. Examination included refraction, best?corrected visual acuity (BCVA), and color vision. Adaptive optics (AO) and multifocal electroretinogram (mf?ERG) were done to assess the anatomy and function of photoreceptors. The subgroup analysis of the improved and non?improved groups was done. Results: The mean cone density in cases and control in the superior, temporal, and nasal quadrants was respectively as follows (21640 ± 5713, 24040 ± 3386, P = 0.01) (19755 ± 6282, 21832 ± 2911, P = 0.03) (19897 ± 5418, 22171 ± 3660, P = 0.01) (20768 ± 4799, 22819 ± 3241, P = 0.01). The amplitude of N1 wave and P1 wave in cases was significantly low compared to the controls. Cases with subnormal color vision had reduced BCVA (0.55 ± 0.018) in comparison to the children with normal response (0.350 ± 0.014). Cone density was also significantly reduced in children with subnormal color vision. Sixteen out of 25 cases showed BCVA improvement with spectacles. Baseline cone density was found to be significantly higher in the improved group. There was no correlation between BCVA and AO parameters. Conclusion: Patients with ametropic amblyopia show subnormal photoreceptor properties than controls. Low cone density may be associated with defective color vision and poor prognosis in these cases
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Adaptive optics(AO)is a technique used to optimize the functionality of optical systems through the reduction of wavefront distortion and optical aberrations. AO-based retinal imaging reduces the occurrence of optical aberrations in the refractive system, consequently improving the resolution and overall quality of retinal imaging. As a result, AO-based retinal imaging has potential wide-ranging application in ophthalmology. A combination of AO, fundus camera, scanning laser ophthalmoscope, optical coherence tomography technique and optical coherence tomography angiography, can be applied to observe the distribution, morphology and function of retinal cone cells in the healthy retinal, and to comprehend the shape and perfusion of retinal vessels in the fine vascular layer. With this technique, it can also possible to perform qualitative and quantitative analysis of the number and shape of cells in the ocular fundus, the cribriform plate, and the microscopic structures of the retinal microvascular system and nerve tissue. It can be expected as a novel tool for the early diagnosis, follow-up of therapy effects, and identification of progression of ophthalmic diseases such as diabetic retinopathy, age-related macular degeneration, glaucoma and hereditary retinal diseases.
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Purpose: To compare image characteristics of retinal nerve fiber layer (RNFL) between glaucoma patients and healthy controls using adaptive optics scanning laser ophthalmoscopy (AOSLO). Methods: This was a cross-sectional pilot study with two groups: a glaucoma group with patients with moderate or severe glaucoma as per the Hodapp–Parrish–Anderson classification system and a control group with healthy individuals. The optic nerve damage in moderate glaucoma was predominantly located in only one hemisphere; the other hemisphere was un- or minimally affected on optical coherence tomography and automated perimetry and is referred to as early glaucoma. The structure of RNFL bundles and gain (%) in RNFL images with mean pixel values between 15 and 35 were analyzed. Imaging was performed one degree away from the optic disc margin at two and four cardinal clock positions in the glaucoma and control groups, respectively. The field of view was 1.3° at 2.3 ? resolution. We studied one eye per participant. Results: There were 11 glaucoma patients and 7 healthy controls. Imaging was successful at 88% of the locations in controls and early glaucoma; the reflectivity differed significantly (0.51 and 0.56, respectively, P < 0.001) but not the structure of RNFL bundles (Cohen’s Kappa 0.11) between them. In patients with moderate and severe glaucoma, imaging was successful only at 46% of the locations; RNFL bundles were not discernible, and RNFL reflectivity did not differ from those with early glaucoma (P < 0.11). Conclusion: The recorded gain (%) of RNFL images obtained using AOSLO could be an objective indicator of early glaucoma
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Adaptive optics (AO) can measure and correct wavefront aberrations in real time, which enables the optical system to adapt to external changes and maintain excellent optical performance, and has been gradually paid attention in the field of ophthalmology.AO technology can carry out optometry according to wavefront aberrations to improve the efficiency and accuracy of subjective and objective refraction, eliminate the influence of ocular aberrations on retinal imaging, provide more accurate data for the evaluation of optic nerve function, improve the effectiveness of visual perception training and provide vision care and treatment for special people, as well as simulate and predict postoperative visual outcome and give personalized schemes for refractive surgery and intraocular lens implantation.Moreover, AO combined with optical coherence tomography, optical scanning laser ophthalmoscope, and confocal scanning laser ophthalmoscope, can realize fundus imaging and retinal vascular imaging in real time, provide better sensitivity and resolution of retinal detection, distinguish fine details of retinal vessels and cone cells, and characterize retinal pigment epithelium topology and deformation, the application of which in posterior segment laser surgery, glaucoma diagnosis and follow-up, color blindness and retinal physiological activity research has been attracting attention.In this article, the principle and application of AO in ophthalmology were briefly reviewed.
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Objective:To evaluate the difference and agreement of cycloplegic refraction between adaptive optics visual simulator (VAO) and conventional refraction methods.Methods:A diagnostic test study was conducted.Thirty-one eyes of 31 healthy subjects including 15 males and 16 females were enrolled in November, 2019 in Affiliated Hospital of North Sichuan Medical College.Mean age of the subjects was (20.1±1.0) years, and the right eye was taken for data analysis.Cycloplegic refraction was measured by VAO and conventional refraction methods, respectively.Spherical power, cylindrical power, Jackson cross-cylinder power at axis 90° and 180° (J 0) and Jackson cross-cylinder power at axis 45° and 135° (J 45) vector powers were recorded.Paired t-test was used to compare the refractive parameters between different refraction methods, and the intraclass correlation coefficient (ICC) and Bland-Altman plots were used to evaluate the agreement between VAO and conventional refraction methods.This study adhered to the Declaration of Helsinki, and the research protocal was approved by an Ethics Committee of Affiliated Hospital of North Sichuan Medical College (No.2020ER[A]018). Written informed consent was obtained from each subject prior to any medical examination. Results:For subjective refraction, the ICC for spherical power, cylindrical power, J 0 and J 45 between VAO and phoropter were 0.97, 0.75, 0.84 and 0.09, respectively.For objective refraction, the ICC for spherical power, cylindrical power, J 0 and J 45 between VAO and autorefractor were 0.98, 0.70, 0.74 and 0.61, respectively.The mean differences in spherical power, cylindrical power, J 0 and J 45 between VAO and phoropter were (0.05±0.32), (-0.23±0.28), (-0.10±0.14) and (-0.04±0.16)D, respectively, and the differences in cylindrical power and J 0 were statistically significant (both at P<0.01), whereas no significant differences in spherical power and J 45 were found ( P=0.41, 0.18). The mean differences in spherical power, cylindrical power, J 0 and J 45 measured by VAO and autorefractor were (-0.70±0.26), (-0.07±0.46), (-0.03±0.27) and (0.01±0.12)D, respectively, and the spherical power measurement by VAO was significantly more negative than the autorefractor ( t=15.09, P<0.01), while no significant differences in cylindrical power, J 0 and J 45 were found ( P=0.39, 0.59, 0.63). No significant difference values in spherical power, cylindrical power, J 0 and J 45 were found between the two objective refraction methods and phoropter subjective refraction (all at P>0.05). Conclusions:With cycloplegia, spherical power obtained by VAO objective refraction is more negative compared with autorefractor.There is a good agreement of spherical power and astigmatism vector values measured by VAO and phoropter subjective refraction, and the measurement differences are clinically acceptable.
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Purpose: To measure the wall-to-lumen ratio (WLR) and the vascular wall cross-sectional area (WCSA) of retinal arterioles by an Adaptive Optics (AO) retinal camera using semi-automated software and comparing them between control and hypertensive population. Methods: This was a cross-sectional observational study including a hypertensive group and a control group. Subjects were examined and their medical history recorded. Retinal arteriolar morphometry was assessed by rtx1 AO retinal camera using AOdetect Artery semiautomated software. Main Outcome Measures: WLR and WCSA were measured on the basis of retinal arteriolar wall thickness (W1, W2), lumen diameter (LD) and vessel diameter (VD). Influence of age and arterial hypertension on the WLR and WCSA were examined. Results: A total of 150 human subjects were included out of which 110 were controls and 40 were hypertensives under treatment. There was statistically significant difference in the age, systolic and diastolic blood pressures between the control and hypertensive groups (P < 0.01). We found no significant correlation between age and WLR (R2 = 0.049, P > 0.05) or age and WCSA (R2 = 0.045, P > 0.05). We observed a significant difference in WLR and WCSA measurements between control and hypertensive groups (P < 0.01). On measuring intra-observer variability (IOV) we found excellent consistency. Conclusion: AO retinal imaging allows a direct measurement of the retinal vessel wall and LD with excellent IOV. WLR and WCSA reflect the remodelling process and can be used to further aid the early detection and monitoring of systemic hypertension.
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We present a case of a 37-year-old gentleman with a rare diagnosis of Torpedo maculopathy (TM). We describe the multimodal imaging features of torpedo maculopathy using adaptive optics, visual fields, OCT and multifocal ERG, and understand the clinical and structural-functional correlation in TM. According to us, this is the first case report to describe the adaptive optics imaging findings in Torpedo maculopathy in English Medical literature.
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Adaptive optics (AO) is a technique to improve the performance of optical systems by reducing the influence of optical aberrations. Combined with scanning laser ophthalmoscope (AOSLO), the aberration of human refractive system can be corrected. Thus, the resolution and quality of imaging can be greatly improved to the cellular level in vivo retina (such as photoreceptor, nerve fibers, vascular parietal cell), therefore the earlier changes of the diseases can be detected. At the same time, microstructure changes of retinal can also be observed during the follow-up of the disease. Due to inherent technical defects of AOSLO, its wide application in clinical practice is limited. With the continuous progress of AO technology and the further improvement of related software functions, the function of the system will become more stronger and will play a more and more important role in scientific research and clinic.
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Adaptive optics (AO) is a technique to improve the performance of optical systems by reducing the influence of optical aberrations.Combined with scanning laser ophthalmoscope (AOSLO),the aberration of human refractive system can be corrected.Thus,the resolution and quality of imaging can be greatly improved to the cellular level in vivo retina (such as photoreceptor,nerve fibers,vascular parietal cell),therefore the earlier changes of the diseases can be detected.At the same time,microstructure changes of retinal can also be observed during the follow-up of the disease.Due to inherent technical defects of AOSLO,its wide application in clinical practice is limited.With the continuous progress of AO technology and the further improvement of related software functions,the function of the system will become more stronger and will play a more and more important role in scientific research and clinic.
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@#AIM:To investigate the accuracy, time-consuming and reliability of three Zernike algorithms in reconstruction of the corneal aberration in adaptive optics.<p>METHODS: Elevation data of corneal front surface collected on 20 normal eyes over a 6mm pupil were converted into the simulated original wave-front data by subtracting the best fitting sphere, which was then resampled at resolutions of 100, 300, and 500μm. Differences in elevation between adjacent pixels were used to generate simulated wave-front slope data, which were used to reconstruct wave-front by three algorithms: the regularized solution, the singular value decomposition, and Householder transform separately. The number of Zernike modes was from 1 to 130 separately in each reconstruction procedure. Each new wave-front map generated was directly compared to the originally sampled wave-front and the residual root-mean-square(RMS)error between the original and reconstructed map was recorded, also we investigate the time-consuming and reliability of the solution by calculating the condition numbers of the linear model and observing the mode coefficient matrix. <p>RESULTS: Householder transformation performed as well as the singular value decomposition by three sampling rates in reconstruction accuracy, while the regularized solution showed unacceptable results when the number Zernike modes used higher than 88 by the resolution was 500μm. With the modes number increased, the time that the singular value decomposition consumed increased more obviously than the time that the Householder transformation and the regularized solution consumed, and the difference between the latter two didn't show obviously. The higher the sampling rate was, also the lower the Zernike exponent number was, and the more reliable the result was, and the instability of regularized solution is more serious than the other two at the low sampling rate.<p>CONCLUSION:Householder transformation is superior the other two in accuracy as well as the highly effectiveness, and the reliability of three algorithms was almost identical at high sampling rate, while the Householder transformation still showed relatively stable performance at low sampling rate, which provides the reference and the theory basis of choice to the optimal algorithm which is applied in the adaptive optics system of real-time correction eyeball's aberration wave-front reconstruction.
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Background The use of adaptive optics (AO) system in ophthalmic clinic and basic studies has increased in recent years.However,there are few reports on the stability of ocular aberrations after correction.Objective This study was to analyze the stability of aberration after correction by observing the repeatability of ocular aberration measurements.Methods Forty-one postgraduate school students and volunteers who meet the conditions were included from February to April 2014.The Zernike aberration coefficients including astigmatism (Z2-2,Z22),defocus (Z02),trefoil (Z33,Z3-3),coma (Z3-1,Z13),spherical aberration (Z40) and the value of root mean square (RMS) including 3rd-order to 7th-order aberrations,total higher-order aberrations (HOAs) and total ocular aberrations (TOAs) were measured by using AO system.The repeatability and stability of these data after corrected with AO system were analyzed.The repeatability was evaluated by ANOVA,within-subject standard deviation (Sw),repeatability (r) and intra-class correlation coefficients (ICC).The stability was evaluated by the nonparametric Friedman's rank test.Results AO system showed excellent repeatability on Z2-2,Z22,Z20 and TOA RMS (ICC＞ 0.9),good repeatability on Z13,Z33,Z3-3,Z40,3rd-order RMS,4th-order RMS,HOA RMS (ICC ＞ 0.75),poor repeatability on Z3-1,5th-order RMS,6th-order RMS,7th-order RMS (ICC ＜ 0.75).Repeatability (2.77 Sw) values ranged from 0.009 mm (7th-order RMS) to 0.163 mm (Z31).After low-order ocular aberrations were corrected,It was founded that Z2-2,Z22 reached stable state at the 4th second;Z02 was stable at the 6th second;Z3-3 and Z33 reached stable state at the 4th second and third second,separately;Z13 was stable from 3rd-second to 9th-second,Z3-1 was stable at the 4th-second.Z40 and HOA RMS were stable at the third second and fifth second,respectively.The Z2-2,Z02,Z22,Z3-3,Z3-1,Z33,Z40 and HOA RMS were significantly different among different time points before and after low-order aberrations correction (all at P ＜ 0.05).Z2-2,Z22,Z20 reached stable state at the 4th-second,3rd-second and 5th-second,respectively;Z3-3,Z33 reached stable state at the 2nd-second and 3rd-second,respectively;Z3-1and Z40 reached stable state at the 2nd-second;HOA RMS reached stable state at the 5th-second.Conclusions After correcting the human ocular aberration,different aberrations can reach stable state at different time.The time of Z02,Z22,Z3-3,Z3-1,Z40reaching stable state after 2nd-order to 5th-order ocular aberrations correction was earlier than those of lower-order aberrations correction.
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Aim: To assess the variations in cone mosaic in myopia and its correlation with axial length (AL). Subjects and Methods: Twenty‑five healthy myopic volunteers underwent assessment of photoreceptors using adaptive optics retinal camera at 2° and 3° from the foveal center in four quadrants superior, inferior, temporal and nasal. Data was analyzed using SPSS version 17 (IBM). Multivariable regression analysis was conducted to study the relation between cone density and AL, quadrant around the fovea and eccentricity from the fovea. Results: The mean cone density was significantly lower as the eccentricity increased from 2° from the fovea to 3° (18,560 ± 5455–16,404 ± 4494/mm2 respectively). There was also a statistically significant difference between four quadrants around the fovea. The correlation of cone density and spacing with AL showed that there was a significant inverse relation of AL with the cone density. Conclusion: In myopic patients with good visual acuity cone density around the fovea depends on the quadrant, distance from the fovea as well as the AL. The strength of the relation of AL with cone density depends on the quadrant and distance.
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Adaptive optics is a relatively new tool that is available to ophthalmologists for study of cellular level details. In addition to the axial resolution provided by the spectral-domain optical coherence tomography, adaptive optics provides an excellent lateral resolution, enabling visualization of the photoreceptors, blood vessels and details of the optic nerve head. We att empt a mini review of the current role of adaptive optics in retinal imaging. PubMed search was performed with key words Adaptive optics OR Retina OR Retinal imaging. Conference abstracts were searched from the Association for Research in Vision and Ophthalmology (ARVO) and American Academy of Ophthalmology (AAO) meetings. In total, 261 relevant publications and 389 conference abstracts were identified.
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A 53-year-old Asian woman was treated with hydroxychloroquine and chloroquine for lupus erythematosus. Within a few years, she noticed circle-shaped shadows in her central vision. Upon examination, the patient's visual acuity was 20 / 25 in both eyes. Humphrey visual field (HVF) testing revealed a central visual defect, and fundoscopy showed a ring-shaped area of parafoveal retinal pigment epithelium depigmentation. Fundus autofluorescence imaging showed a hypofluorescent lesion consistent with bull's eye retinopathy. Adaptive optics scanning laser ophthalmoscope (AO-SLO) revealed patch cone mosaic lesions, in which cones were missing or lost. In addition, the remaining cones consisted of asymmetrical shapes and sizes that varied in brightness. Unlike previous studies employing deformable mirrors for wavefront aberration correction, our AO-SLO approach utilized dual liquid crystal on silicon spatial light modulators. Thus, by using AO-SLO, we were able to create a photographic montage consisting of high quality images. Disrupted cone AO-SLO images were matched with visual field test results and functional deficits were associated with a precise location on the montage, which allowed correlation of histological findings with functional changes determined by HVF. We also investigated whether adaptive optics imaging was more sensitive to anatomical changes compared with spectral-domain optical coherence tomography.
Subject(s)
Female , Humans , Middle Aged , Chloroquine/adverse effects , Diagnosis, Differential , Image Enhancement/methods , Lupus Erythematosus, Systemic/drug therapy , Macula Lutea/drug effects , Ophthalmoscopy/methods , Retinal Diseases/chemically inducedABSTRACT
A 53-year-old Asian woman was treated with hydroxychloroquine and chloroquine for lupus erythematosus. Within a few years, she noticed circle-shaped shadows in her central vision. Upon examination, the patient's visual acuity was 20 / 25 in both eyes. Humphrey visual field (HVF) testing revealed a central visual defect, and fundoscopy showed a ring-shaped area of parafoveal retinal pigment epithelium depigmentation. Fundus autofluorescence imaging showed a hypofluorescent lesion consistent with bull's eye retinopathy. Adaptive optics scanning laser ophthalmoscope (AO-SLO) revealed patch cone mosaic lesions, in which cones were missing or lost. In addition, the remaining cones consisted of asymmetrical shapes and sizes that varied in brightness. Unlike previous studies employing deformable mirrors for wavefront aberration correction, our AO-SLO approach utilized dual liquid crystal on silicon spatial light modulators. Thus, by using AO-SLO, we were able to create a photographic montage consisting of high quality images. Disrupted cone AO-SLO images were matched with visual field test results and functional deficits were associated with a precise location on the montage, which allowed correlation of histological findings with functional changes determined by HVF. We also investigated whether adaptive optics imaging was more sensitive to anatomical changes compared with spectral-domain optical coherence tomography.