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Woertz EN, Ayala GD, Wynne N, Tarima S, Zacharias S, Brilliant MH, Dunn TM, Costakos D, Summers CG, Strul S, Drack AV, Carroll J. Quantitative Foveal Structural Metrics as Predictors of Visual Acuity in Human Albinism. Invest Ophthalmol Vis Sci 2024; 65:3. [PMID: 38441889 PMCID: PMC10916884 DOI: 10.1167/iovs.65.3.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 01/03/2024] [Indexed: 03/07/2024] Open
Abstract
Purpose To assess the degree to which quantitative foveal structural measurements account for variation in best-corrected visual acuity (BCVA) in human albinism. Methods BCVA was measured and spectral domain optical coherence tomography (SD-OCT) images were acquired for 74 individuals with albinism. Categorical foveal hypoplasia grades were assessed using the Leicester Grading System for Foveal Hypoplasia. Foveal anatomical specialization (foveal versus parafoveal value) was quantified for inner retinal layer (IRL) thickness, outer segment (OS) length, and outer nuclear layer (ONL) thickness. These metrics, participant sex, and age were used to build a multiple linear regression of BCVA. This combined linear model's predictive properties were compared to those of categorical foveal hypoplasia grading. Results The cohort included three participants with type 1a foveal hypoplasia, 23 participants with type 1b, 33 with type 2, ten with type 3, and five with type 4. BCVA ranged from 0.08 to 1.00 logMAR (mean ± SD: 0.53 ± 0.21). IRL ratio, OS ratio, and ONL ratio were measured in all participants and decreased with increasing severity of foveal hypoplasia. The best-fit combined linear model included all three quantitative metrics and participant age expressed as a binary variable (divided into 0-18 years and 19 years or older; adjusted R2 = 0.500). This model predicted BCVA more accurately than a categorical foveal hypoplasia model (adjusted R2 = 0.352). Conclusions A quantitative model of foveal specialization accounts for more variance in BCVA in albinism than categorical foveal hypoplasia grading. Other factors, such as optical aberrations and eye movements, may account for the remaining unexplained variance.
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Affiliation(s)
- Erica N. Woertz
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
- School of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Gelique D. Ayala
- School of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Niamh Wynne
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Sergey Tarima
- Division of Biostatistics, Institute for Health and Equity, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Serena Zacharias
- School of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Murray H. Brilliant
- Center for Precision Medicine Research, Marshfield Clinic, Marshfield, Wisconsin, United States
| | - Taylor M. Dunn
- Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama, United States
- Department of Ophthalmology and Visual Sciences, University of Iowa Hospitals and Clinics, Iowa City, Iowa, United States
| | - Deborah Costakos
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - C. Gail Summers
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States
| | - Sasha Strul
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States
| | - Arlene V. Drack
- Department of Ophthalmology and Visual Sciences, University of Iowa Hospitals and Clinics, Iowa City, Iowa, United States
| | - Joseph Carroll
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
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2
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Proudlock FA, McLean RJ, Sheth V, Ather S, Gottlob I. Phenotypic Features Determining Visual Acuity in Albinism and the Role of Amblyogenic Factors. Invest Ophthalmol Vis Sci 2024; 65:14. [PMID: 38319667 PMCID: PMC10854414 DOI: 10.1167/iovs.65.2.14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 01/05/2024] [Indexed: 02/07/2024] Open
Abstract
Albinism is a spectrum disorder causing foveal hypoplasia, nystagmus, and hypopigmentation of the iris and fundus along with other visual deficits, which can all impact vision. Albinism is also associated with amblyogenic factors which could affect monocular visual acuity. The foveal appearance in albinism can range from mild foveal hypoplasia to that which is indistinguishable from the peripheral retina. The appearance can be quickly and easily graded using the Leicester Grading System in the clinic. However, interquartile ranges of 0.3 logMAR for the grades associated with albinism limit the accuracy of the grading system in predicting vision. Here, we discuss the potential role of nystagmus presenting evidence that it may not be a major source of variability in the prediction of visual acuity. We also show that interocular differences in visual acuity are low in albinism despite high levels of amblyogenic factors indicating that active suppression of vision in one eye in albinism is uncommon.
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Affiliation(s)
- Frank A Proudlock
- The University of Leicester Ulverscroft Eye Unit, Psychology and Vision Sciences, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, United Kingdom
| | - Rebecca J McLean
- The University of Leicester Ulverscroft Eye Unit, Psychology and Vision Sciences, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, United Kingdom
| | - Viral Sheth
- The University of Leicester Ulverscroft Eye Unit, Psychology and Vision Sciences, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, United Kingdom
- Health Sciences School, University of Sheffield, Sheffield, Yorkshire, United Kingdom
| | - Sarim Ather
- Oxford University Hospitals NHS Foundation Trust, Headley Way, Headington, Oxfordshire, United Kingdom
| | - Irene Gottlob
- The University of Leicester Ulverscroft Eye Unit, Psychology and Vision Sciences, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, United Kingdom
- Department of Neurology, Cooper University Health Care, Cooper Medical School of Rowan University, Camden, New Jersey, United States
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Britten-Jones AC, Thai L, Flanagan JPM, Bedggood PA, Edwards TL, Metha AB, Ayton LN. Adaptive optics imaging in inherited retinal diseases: A scoping review of the clinical literature. Surv Ophthalmol 2024; 69:51-66. [PMID: 37778667 DOI: 10.1016/j.survophthal.2023.09.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 09/22/2023] [Accepted: 09/25/2023] [Indexed: 10/03/2023]
Abstract
Adaptive optics (AO) imaging enables direct, objective assessments of retinal cells. Applications of AO show great promise in advancing our understanding of the etiology of inherited retinal disease (IRDs) and discovering new imaging biomarkers. This scoping review systematically identifies and summarizes clinical studies evaluating AO imaging in IRDs. Ovid MEDLINE and EMBASE were searched on February 6, 2023. Studies describing AO imaging in monogenic IRDs were included. Study screening and data extraction were performed by 2 reviewers independently. This review presents (1) a broad overview of the dominant areas of research; (2) a summary of IRD characteristics revealed by AO imaging; and (3) a discussion of methodological considerations relating to AO imaging in IRDs. From 140 studies with AO outcomes, including 2 following subretinal gene therapy treatments, 75% included fewer than 10 participants with AO imaging data. Of 100 studies that included participants' genetic diagnoses, the most common IRD genes with AO outcomes are CNGA3, CNGB3, CHM, USH2A, and ABCA4. Confocal reflectance AO scanning laser ophthalmoscopy was the most reported imaging modality, followed by flood-illuminated AO and split-detector AO. The most common outcome was cone density, reported quantitatively in 56% of studies. Future research areas include guidelines to reduce variability in the reporting of AO methodology and a focus on functional AO techniques to guide the development of therapeutic interventions.
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Affiliation(s)
- Alexis Ceecee Britten-Jones
- Department of Optometry and Vision Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia; Department of Surgery (Ophthalmology), Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia; Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, VIC, Australia.
| | - Lawrence Thai
- Department of Surgery (Ophthalmology), Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia; Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, VIC, Australia
| | - Jeremy P M Flanagan
- Department of Surgery (Ophthalmology), Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia; Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, VIC, Australia
| | - Phillip A Bedggood
- Department of Optometry and Vision Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Thomas L Edwards
- Department of Surgery (Ophthalmology), Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia; Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, VIC, Australia
| | - Andrew B Metha
- Department of Optometry and Vision Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Lauren N Ayton
- Department of Optometry and Vision Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia; Department of Surgery (Ophthalmology), Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia; Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, VIC, Australia
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The retinal pigmentation pathway in human albinism: Not so black and white. Prog Retin Eye Res 2022; 91:101091. [PMID: 35729001 DOI: 10.1016/j.preteyeres.2022.101091] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 05/24/2022] [Accepted: 05/26/2022] [Indexed: 12/16/2022]
Abstract
Albinism is a pigment disorder affecting eye, skin and/or hair. Patients usually have decreased melanin in affected tissues and suffer from severe visual abnormalities, including foveal hypoplasia and chiasmal misrouting. Combining our data with those of the literature, we propose a single functional genetic retinal signalling pathway that includes all 22 currently known human albinism disease genes. We hypothesise that defects affecting the genesis or function of different intra-cellular organelles, including melanosomes, cause syndromic forms of albinism (Hermansky-Pudlak (HPS) and Chediak-Higashi syndrome (CHS)). We put forward that specific melanosome impairments cause different forms of oculocutaneous albinism (OCA1-8). Further, we incorporate GPR143 that has been implicated in ocular albinism (OA1), characterised by a phenotype limited to the eye. Finally, we include the SLC38A8-associated disorder FHONDA that causes an even more restricted "albinism-related" ocular phenotype with foveal hypoplasia and chiasmal misrouting but without pigmentation defects. We propose the following retinal pigmentation pathway, with increasingly specific genetic and cellular defects causing an increasingly specific ocular phenotype: (HPS1-11/CHS: syndromic forms of albinism)-(OCA1-8: OCA)-(GPR143: OA1)-(SLC38A8: FHONDA). Beyond disease genes involvement, we also evaluate a range of (candidate) regulatory and signalling mechanisms affecting the activity of the pathway in retinal development, retinal pigmentation and albinism. We further suggest that the proposed pigmentation pathway is also involved in other retinal disorders, such as age-related macular degeneration. The hypotheses put forward in this report provide a framework for further systematic studies in albinism and melanin pigmentation disorders.
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Wynne N, Carroll J, Duncan JL. Promises and pitfalls of evaluating photoreceptor-based retinal disease with adaptive optics scanning light ophthalmoscopy (AOSLO). Prog Retin Eye Res 2021; 83:100920. [PMID: 33161127 PMCID: PMC8639282 DOI: 10.1016/j.preteyeres.2020.100920] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 10/28/2020] [Accepted: 10/31/2020] [Indexed: 12/15/2022]
Abstract
Adaptive optics scanning light ophthalmoscopy (AOSLO) allows visualization of the living human retina with exquisite single-cell resolution. This technology has improved our understanding of normal retinal structure and revealed pathophysiological details of a number of retinal diseases. Despite the remarkable capabilities of AOSLO, it has not seen the widespread commercial adoption and mainstream clinical success of other modalities developed in a similar time frame. Nevertheless, continued advancements in AOSLO hardware and software have expanded use to a broader range of patients. Current devices enable imaging of a number of different retinal cell types, with recent improvements in stimulus and detection schemes enabling monitoring of retinal function, microscopic structural changes, and even subcellular activity. This has positioned AOSLO for use in clinical trials, primarily as exploratory outcome measures or biomarkers that can be used to monitor disease progression or therapeutic response. AOSLO metrics could facilitate patient selection for such trials, to refine inclusion criteria or to guide the choice of therapy, depending on the presence, absence, or functional viability of specific cell types. Here we explore the potential of AOSLO retinal imaging by reviewing clinical applications as well as some of the pitfalls and barriers to more widespread clinical adoption.
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Affiliation(s)
- Niamh Wynne
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Joseph Carroll
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA; Department of Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA; Department of Biomedical Engineering, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Jacque L Duncan
- Department of Ophthalmology, University of California, San Francisco, CA, USA.
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Litts KM, Woertz EN, Wynne N, Brooks BP, Chacon A, Connor TB, Costakos D, Dumitrescu A, Drack AV, Fishman GA, Hauswirth WW, Kay CN, Lam BL, Michaelides M, Pennesi ME, Stepien KE, Strul S, Summers CG, Carroll J. Examining Whether AOSLO-Based Foveal Cone Metrics in Achromatopsia and Albinism Are Representative of Foveal Cone Structure. Transl Vis Sci Technol 2021; 10:22. [PMID: 34111268 PMCID: PMC8132001 DOI: 10.1167/tvst.10.6.22] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Adaptive optics scanning light ophthalmoscopy (AOSLO) imaging in patients with achromatopsia (ACHM) and albinism is not always successful. Here, we tested whether optical coherence tomography (OCT) measures of foveal structure differed between patients for whom AOSLO images were either quantifiable or unquantifiable. Methods The study included 166 subjects (84 with ACHM; 82 with albinism) with previously acquired OCT scans, AOSLO images, and best-corrected visual acuity (BCVA, if available). Foveal OCT scans were assessed for outer retinal structure, outer nuclear layer thickness, and hypoplasia. AOSLO images were graded as quantifiable if a peak cone density could be measured and/or usable if the location of peak density could be identified and the parafoveal mosaic was quantifiable. Results Forty-nine percent of subjects with ACHM and 57% of subjects with albinism had quantifiable AOSLO images. Older age and better BCVA were found in subjects with quantifiable AOSLO images for both ACHM (P = 0.0214 and P = 0.0276, respectively) and albinism (P = 0.0073 and P < 0.0004, respectively). There was a significant trend between ellipsoid zone appearance and ability to quantify AOSLO (P = 0.0028). In albinism, OCT metrics of cone structure did not differ between groups. Conclusions Previously reported AOSLO-based cone density measures in ACHM may not necessarily reflect the degree of remnant cone structure in these patients. Translational Relevance Until AOSLO is successful in all patients with ACHM and albinism, the possibility of the reported data from a particular cohort not being representative of the entire population remains an important issue to consider when interpreting results from AOSLO studies.
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Affiliation(s)
- Katie M Litts
- Department of Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Erica N Woertz
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA.,School of Medicine, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Niamh Wynne
- Department of Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA
| | | | - Alicia Chacon
- Department of Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Thomas B Connor
- Department of Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Deborah Costakos
- Department of Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Alina Dumitrescu
- Department of Ophthalmology and Visual Sciences, University of Iowa Hospitals and Clinics, Iowa City, IA, USA
| | - Arlene V Drack
- Department of Ophthalmology and Visual Sciences, University of Iowa Hospitals and Clinics, Iowa City, IA, USA
| | - Gerald A Fishman
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, IL, USA
| | | | | | - Byron L Lam
- Bascom Palmer Eye Institute, University of Miami, Miami, FL, USA
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Mark E Pennesi
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, USA
| | - Kimberly E Stepien
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, USA
| | - Sasha Strul
- Department of Ophthalmology & Visual Neurosciences, University of Minnesota, Minneapolis, MN, USA
| | - C Gail Summers
- Department of Ophthalmology & Visual Neurosciences, University of Minnesota, Minneapolis, MN, USA
| | - Joseph Carroll
- Department of Ophthalmology & Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA.,Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA
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7
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Duwell EJ, Woertz EN, Mathis J, Carroll J, DeYoe EA. Aberrant visual population receptive fields in human albinism. J Vis 2021; 21:19. [PMID: 34007988 PMCID: PMC8142699 DOI: 10.1167/jov.21.5.19] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 04/15/2021] [Indexed: 11/27/2022] Open
Abstract
Retinotopic organization is a fundamental feature of visual cortex thought to play a vital role in encoding spatial information. One important aspect of normal retinotopy is the representation of the right and left hemifields in contralateral visual cortex. However, in human albinism, many temporal retinal afferents decussate aberrantly at the optic chiasm resulting in partially superimposed representations of opposite hemifields in each hemisphere of visual cortex. Previous functional magnetic resonance imaging (fMRI) studies in human albinism suggest that the right and left hemifield representations are superimposed in a mirror-symmetric manner. This should produce imaging voxels which respond to two separate locations mirrored across the vertical meridian. However, it is not yet clear how retino-cortical miswiring in albinism manifests at the level of single voxel population receptive fields (pRFs). Here, we used pRF modeling to fit both single and dual pRF models to the visual responses of voxels in visual areas V1 to V3 of five subjects with albinism. We found that subjects with albinism (but not controls) have sizable clusters of voxels with unequivocal dual pRFs consistently corresponding to, but not fully coextensive with, regions of hemifield overlap. These dual pRFs were typically positioned at locations roughly mirrored across the vertical meridian and were uniquely clustered within a portion of the visual field for each subject.
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Affiliation(s)
- Ethan J Duwell
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Erica N Woertz
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA
| | | | - Joseph Carroll
- Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI, USA
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, WI, USA
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Edgar A DeYoe
- Department of Radiology, Medical College of Wisconsin, Milwaukee, WI, USA
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