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Documenta Ophthalmologica. Advances in... Oct 2021The purpose of this study was to assess eye movements during a multifocal ERG (mfERG) recording. This study evaluated the relationship between bivariate contour ellipse...
PURPOSE
The purpose of this study was to assess eye movements during a multifocal ERG (mfERG) recording. This study evaluated the relationship between bivariate contour ellipse areas (BCEAs), mfERG amplitudes (Amps) and mfERG implicit times (ITs) with repeat testing and experienced subjects.
METHODS
Thirty subjects were selected (15 experienced to ocular procedures and 15 novices). All were confirmed to have healthy retinas and at least 20/25 vision. MfERGs with a stimulus near 100% contrast and 4-min m-sequence were recorded on two different days using our common clinical technique, which did not constrain the head. VERIS with fundus monitoring system was used for recording with a Burian-Allen electrode. An external camera captured the fundus during each mfERG recording. The optic nerve head position was tracked in each video using a custom algorithm in order to determine BCEAs. Each subject performed one mfERG on two different days. MfERGs were analyzed for Amps and ITs for the fovea and whole eye.
RESULTS
There was no correlation between the mfERG metrics and BCEAs with repeat testing. There were also no differences between the experienced and novice subjects for mfERG Amps, ITs or BCEAs. Eye movements between visits were highly correlated (multiple r = 0.67). BCEAs were larger during mfERGs (1.04 ± 0.8 deg) than those observed in previous literature using brief viewing tasks (< 0.3 deg). The proportion of time spent fixating within 1.0 and 2.0 degrees of the central hexagon was 68 and 93%, respectively.
CONCLUSIONS
This study is the first to evaluate the stability of the retina while recording a mfERG in healthy subjects and indicates that the center of fixation during a mfERG stays within the central hexagon. Eye stability during an initial recording is the best indicator of stability on the second recording. The amount of movement during these recordings did not seem to affect the mfERG Amps or ITs. These data suggest clinical confidence with mfERGs when recording novice patients.
Topics: Electroretinography; Fovea Centralis; Fundus Oculi; Humans; Optic Disk; Retina
PubMed: 33713340
DOI: 10.1007/s10633-021-09829-9 -
Ophthalmic & Physiological Optics : the... Jan 2024To analyse ocular coherence tomography (OCT) images of the retinal shadows caused by defocus and diffusion optics spectacles.
PURPOSE
To analyse ocular coherence tomography (OCT) images of the retinal shadows caused by defocus and diffusion optics spectacles.
METHODS
One eye was fitted successively with the Hoya Defocus Incorporated Multiple Segments (DIMS) spectacle lens, two variations of the +3.50 D peripheral add spectacle (DEFOCUS) and the low-contrast dot lens (Diffusion Optics Multiple Segments, DOMS); each at a vertex distance of 12 mm. Simultaneously, a retinal image of the macular region with central fixation was obtained using infrared OCT. The corneal power and intraocular distances were determined using an optical biometer.
RESULTS
The retinal images for the DIMS and DOMS lenses showed patterns of obvious retinal shadows in the periphery, while the central 10-11° remained clear. The DEFOCUS lens produced a darkened peripheral area. Dividing the size of the retinal pattern, measured with the calliper of the OCT software, by the actual size on the spectacle lens gave a magnification of -0.57 times. This is consistent with the incoming OCT beam being imaged to a position approximately 31 mm beyond the front of the eye. [Correction added on 26 October 2023 after first online publication: The preceding paragraph was corrected.] CONCLUSION: With device-specific correction, retinal OCT images can help visualise the regions affected by the defocus or lowered contrast induced by myopia control spectacles. This is of potential value for improving myopia therapies.
Topics: Humans; Refraction, Ocular; Eyeglasses; Myopia; Retina; Lens, Crystalline
PubMed: 37642972
DOI: 10.1111/opo.13228 -
Experimental Biology and Medicine... Oct 2021By providing the sectioning capability to differentiate individual retinal layers, optical coherence tomography (OCT) is revolutionizing eye disease diagnosis and... (Review)
Review
By providing the sectioning capability to differentiate individual retinal layers, optical coherence tomography (OCT) is revolutionizing eye disease diagnosis and treatment evaluation. A better understanding of the hyper- and hypo-reflective bands in retinal OCT is essential for accurate interpretation of clinical outcomes. In this article, we summarize the interpretations of clinical OCT and adaptive optics (AO) OCT (AO-OCT) of the outer retina in the human eye, and briefly review OCT investigation of the outer retina in animal models. Quantitative analysis of outer retinal OCT bands is compared to established parameters of retinal histology. The literature review and comparative analysis support that both inner/outer segment (IS/OS) junction and IS ellipsoid zone nonexclusively contribute to the second band; and OS, OS tips, and retinal pigment epithelium apical processes contribute to the third band in conventional OCT. In contrast, AO-OCT might predominantly detect the IS/OS junction and OS tip signals at the second and third bands due to its improved sectioning capability and possible AO effect on the sensitivities for recording ballistic and diffusive photons from different regions of the outer retina.
Topics: Animals; Eye Diseases; Fovea Centralis; Humans; Photoreceptor Cells, Vertebrate; Ranidae; Retinal Pigment Epithelium; Tomography, Optical Coherence
PubMed: 34111984
DOI: 10.1177/15353702211022674 -
Journal of Cataract and Refractive... Oct 2022To assess the agreement between 2 swept-source optical coherence tomography biometry devices, Anterion and IOLMaster 700.
PURPOSE
To assess the agreement between 2 swept-source optical coherence tomography biometry devices, Anterion and IOLMaster 700.
SETTING
Tertiary referral center, Brisbane, Australia.
DESIGN
Prospective comparative study.
METHODS
Bland-Altman analysis was used to assess agreement between devices for flat (K1), steep (K2), and mean (Km) keratometry for anterior, posterior, and total cornea, lens thickness (LT), anterior chamber depth (ACD), central corneal thickness (CCT), white to white (WTW), and axial length (AL). Generalized estimating equations were used to control for within-patient between-eye correlations. Interdevice differences were considered clinically significant if they were likely to alter the spherical refractive outcome by 0.25 diopter (D) or more.
RESULTS
159 eyes of 91 patients (41 male, 50 female) were included. Statistically significant differences were found for K1, K2, and Km for anterior, posterior, and total cornea. When the Anterion was compared with the IOLMaster 700, the mean differences were as follows: anterior K1: -0.17 D, anterior K2: -0.18 D, anterior Km: -0.17 D, posterior K1: -0.38 D, posterior K2: -0.36 D, posterior Km: -0.37 D, total K1: -0.65 D, total K2: -0.82 D, and total Km: -0.74 D. The difference in posterior and total K metrics was clinically significant. Statistically significant differences were noted for LT: 0.159 mm, CCT: -0.004 mm, ACD: 0.054 mm, and WTW: -0.152 mm, although these were not found to be clinically significant. There was no significant difference between devices for AL.
CONCLUSIONS
This study found statistically and clinically significant differences for both posterior and total keratometry between the Anterion and the IOLMaster 700. Posterior and total corneal parameters cannot be considered interchangeable between devices.
Topics: Anterior Chamber; Axial Length, Eye; Biometry; Cornea; Female; Humans; Male; Prospective Studies; Reproducibility of Results; Tomography, Optical Coherence
PubMed: 35333792
DOI: 10.1097/j.jcrs.0000000000000942 -
Asia-Pacific Journal of Ophthalmology... 2019The 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... (Review)
Review
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.
Topics: Axial Length, Eye; Bruch Membrane; Disease Progression; Humans; Macula Lutea; Myopia; Optic Disk
PubMed: 31425168
DOI: 10.1097/01.APO.0000578944.25956.8b -
Clinical & Experimental Optometry Jan 2021Optical coherence tomography angiography (OCT-A) is a non-invasive imaging modality for assessing the vasculature within ocular structures including the retina, macula,... (Review)
Review
Optical coherence tomography angiography (OCT-A) is a non-invasive imaging modality for assessing the vasculature within ocular structures including the retina, macula, choroid and optic nerve. OCT-A has a wide range of clinical applications in various optometric conditions which have been independently reported in the literature. This paper aims to present a review of the current literature on the clinical application of OCT-A in optometric practice as well as to analyse and evaluate the quality of the available evidence. This review included 78 articles from a literature search conducted on 26 May 2019 across the following databases: Cochrane Library of Systematic Reviews, Medline, Scopus and Web of Science. Primary ocular pathologies discussed in this review include glaucoma, diabetic retinopathy, age-related macular degeneration, myopia, acquired and congenital macular dystrophies, epiretinal membrane, retinal vein occlusion, retinitis pigmentosa, choroidal melanoma, uveitis, central serous chorioretinopathy, amblyopia and optic neuropathies. Primary outcome variables included vessel density, foveal avascular zone area and diameter, flow velocity and flow index. This review aims to evaluate the evidence available for OCT-A applications in diagnosis and prognosis of ocular conditions in an optometric setting.
Topics: Fluorescein Angiography; Humans; Macula Lutea; Retina; Retinal Vessels; Systematic Reviews as Topic; Tomography, Optical Coherence
PubMed: 32285493
DOI: 10.1111/cxo.13068 -
Annual Review of Vision Science Sep 2019Retinal function has long been studied with psychophysical methods in humans, whereas detailed functional studies of vision have been conducted mostly in animals owing... (Review)
Review
Retinal function has long been studied with psychophysical methods in humans, whereas detailed functional studies of vision have been conducted mostly in animals owing to the invasive nature of physiological approaches. There are exceptions to this generalization, for example, the electroretinogram. This review examines exciting recent advances using in vivo retinal imaging to understand the function of retinal neurons. In some cases, the methods have existed for years and are still being optimized. In others, new methods such as optophysiology are revealing novel patterns of retinal function in animal models that have the potential to change our understanding of the functional capacity of the retina. Together, the advances in retinal imaging mark an important milestone that shifts attention away from anatomy alone and begins to probe the function of healthy and diseased eyes.
Topics: Animals; Humans; Ophthalmoscopy; Optics and Photonics; Retina; Retinal Neurons; Tomography, Optical Coherence; Vision, Ocular
PubMed: 31525142
DOI: 10.1146/annurev-vision-091517-034239 -
Journal of Cataract and Refractive... Jul 2022To compare axial length (AL) measurements obtained by optical biometry (OB) and immersion ultrasound (iUS) to investigate the agreement between the 2 techniques and how...
PURPOSE
To compare axial length (AL) measurements obtained by optical biometry (OB) and immersion ultrasound (iUS) to investigate the agreement between the 2 techniques and how to use OB constants for eyes with AL by iUS.
SETTING
Multicenter study.
DESIGN
Retrospective observational case series.
METHODS
Agreement between OB and iUS ALs was investigated in 4 subsets. Also, in a test database, the prediction error (PE) for iUS AL was assessed with 4 methods: (1) data-optimized constants; (2) user group for laser interference biometry (ULIB) constants with iUS biometry; (3) with recalibrated AL; and (4) ULIB A-constant - 0.23.
RESULTS
A Combined 1970 eyes were measured with both OB and iUS biometry. OB mean AL was 0.0873 mm longer than iUS AL. The latter was made equivalent to OB ALs with this equation: Recalibrated iUS AL = 1.0228 × iUS AL - 0.4556. In a fifth database (n = 1079) with OB AL measurements only, after AL was artificially shortened by 0.0873 mm, the original A-constant had to be reduced by 0.23 to maintain a zero PE. In a sixth database (n = 127) with iUS AL, the original ULIB A-constant provided the poorest outcomes. Using either recalibrated iUS AL or ULIB A-constant - 0.23 zeroed out the mean PE and achieved the lowest median absolute error.
CONCLUSIONS
AL measurements by iUS can be used with ULIB constants for OB by subtracting 0.23 from the A-constant; alternatively, the iUS AL may be recalibrated. The recalibrated iUS AL should be treated as AL measurements obtained by OB. It is longer than iUS AL in long eyes.
Topics: Axial Length, Eye; Biometry; Eye; Humans; Immersion; Lenses, Intraocular; Optics and Photonics; Refraction, Ocular; Retrospective Studies
PubMed: 34759175
DOI: 10.1097/j.jcrs.0000000000000865 -
Asia-Pacific Journal of Ophthalmology... Nov 2022The diagnosis of glaucoma depends upon indentification of characteristic damage to the optic nerve and retinal fiber layer. In many cases, however, clinicians find it...
The diagnosis of glaucoma depends upon indentification of characteristic damage to the optic nerve and retinal fiber layer. In many cases, however, clinicians find it difficult to ascertain whether glaucomatous damage is present or absent. These patients are often labeled as "glaucoma suspects," which creates a subpopulation of individuals without clear-cut disease who nonetheless must remain under surveillance. Most will never go on to develop glaucoma, yet the need for ongoing monitoring burdens clinics and health care systems. In this perspective, we illustrate possible directions and novel approaches that can be used to remedy this situation by integrating current technologies into clinical practice. In particular, we suggest that optical coherence tomography be better utilized to methodologically classify these eyes into glaucomatous and healthy categories.
Topics: Humans; Optic Disk; Nerve Fibers; Retinal Ganglion Cells; Intraocular Pressure; Ocular Hypertension; Glaucoma; Tomography, Optical Coherence
PubMed: 36278943
DOI: 10.1097/APO.0000000000000564 -
Vestnik Oftalmologii 2022The article presents five cases of various forms of hemangiomas of the optic nerve head (ONH) and juxtapapillary retina that were monitored and analyzed using ocular...
The article presents five cases of various forms of hemangiomas of the optic nerve head (ONH) and juxtapapillary retina that were monitored and analyzed using ocular visualization methods. The obtained data allowed a conclusion that capillary hemangioma of the ONH features clearly-seen boundaries of the lesion both on ophthalmoscopy and optical coherence tomography (OCT) images; on the other hand, juxtapapillary granuloma can be characterized by blurred outlines on ophthalmoscopy and a gradual transition of the altered retina on OCT images with secondary changes seen in the macular area. When comorbid, capillary hemangioma of the ONH and retina feature a combination of these visualization signs.
Topics: Hemangioma, Capillary; Humans; Ophthalmoscopy; Optic Disk; Retina; Tomography, Optical Coherence
PubMed: 35488564
DOI: 10.17116/oftalma202213802166