Optical Coherence Tomography and Neuro-Ophthalmology

Augmented Reality in Ophthalmology: Applications and Challenges

Augmented reality (AR) has been developed rapidly and implemented in many fields such as medicine, maintenance, and cultural heritage. Unlike other specialties, ophthalmology connects closely with AR since most AR systems are based on vision systems. Here we summarize the applications and challenges of AR in ophthalmology and provide insights for further research. Firstly, we illustrate the structure of the standard AR system and present essential hardware. Secondly, we systematically introduce applications of AR in ophthalmology, including therapy, education, and clinical assistance. To conclude, there is still a large room for development, which needs researchers to pay more effort. Applications in diagnosis and protection might be worth exploring. Although the obstacles of hardware restrict the development of AR in ophthalmology at present, the AR will realize its potential and play an important role in ophthalmology in the future with the rapidly developing technology and more in-depth research.

Optical Coherence Tomography Neuro-Toolbox for the Diagnosis and Management of Papilledema, Optic Disc Edema, and Pseudopapilledema

BACKGROUND

Distinguishing optic disc edema from pseudopapilledema is a common, sometimes challenging clinical problem. Advances in spectral-domain optical coherence tomography (SD-OCT) of the optic nerve head (ONH) has proven to be a cost effective, noninvasive, outpatient procedure that may help. At its core are tools that quantify the thickness of the retinal nerve fiber layer (RNFL) and ganglion cell-inner plexiform layer (GC-IPL). The SD-OCT also provides a set of tools that may be qualitatively interpreted in the same way that we read an MRI. They include the transverse axial, en face, and circular tomogram. Our goal is to describe a practical office-based set of tools using SD-OCT in the diagnosis and monitoring of papilledema, optic disc edema, and pseudopapilledema.

EVIDENCE ACQUISITION

Searches on PubMed were performed using combinations of the following key words: OCT, papilledema, pseudopapilledema, optic disc drusen, retinal folds (RF), and choroidal folds (CF).

RESULTS

The principal elements of SD-OCT analysis of the ONH are the RNFL and GC-IPL thickness; however, these metrics have limitations when swelling is severe. Qualitative interpretation of the transverse axial SD-OCT aids in assessing peripapillary shape that may help distinguish papilledema from pseudopapilledema, evaluate atypical optic neuropathies, diagnose shunt failures, and identify outer RF and CF. There is a consensus that the SD-OCT is the most sensitive way of identifying buried optic disc drusen. En face SD-OCT is especially effective at detecting peripapillary wrinkles and outer retinal creases, both of which are common and distinctive signs of optic disc edema that rule out pseudopapilledema. Mechanically stressing the ONH in the adducted eye position, in patients with papilledema, may expose folds and peripapillary deformations that may not be evident in primary position. We also discuss how to optimize the acquisition and registration of SD-OCT images.

CONCLUSIONS

The SD-OCT is not a substitute for a complete history and a careful examination. It is, however, a convenient ancillary test that aids in the diagnosis and management of papilledema, optic disc edema, and pseudopapilledema. It is particularly helpful in monitoring changes over the course of time and distinguishing low-grade papilledema from buried drusen. The application of the SD-OCT toolbox depends on optimizing the acquisition of images, understanding its limitations, recognizing common artifacts, and accurately interpreting images in the context of both history and clinical findings.

The Retinal Nerve Fiber Layer: How William F. Hoyt Opened Our Eyes to It

Retinal nerve fiber layer (RNFL) assessment based on optical coherence tomography has become an essential structural parameter in the evaluation of the visual pathway. Yet, it was the trailblazing efforts of one individual, William F. Hoyt, MD, who in the 1970s published a series of landmark reports, which lay the foundation for evaluating the RNFL. With the aid of a direct ophthalmoscope, red-free photographic techniques, and an inquisitive mind, Hoyt added an entirely new dimension to the importance of careful ophthalmoscopy. This article chronicles the discoveries and publications that allowed Hoyt and his coworkers to establish the importance of analysis of the RNFL.

Retinal nerve fiber layer changes in migraine: A protocol for systematic review and meta-analysis

BACKGROUND

Migraine is a common neurological disease, which seriously affects the quality of life and daily activities of patients. Although migraine is a transient phenomenon of cerebral vasoconstriction, it is well documented that recurrent attacks of migraine may lead to abnormalities in retinal structure. Optical coherence tomography (OCT) is a sensitive method to detect subtle damage in retinal nerve fiber layer (RNFL). There have been many studies investigating the difference in RNFL thickness with optical coherence tomography (OCT) between migraine patients and healthy controls. However, the results were not consistent. Our purpose is to perform a meta-analysis to investigate RNFL alterations in migraine.

METHODS

We will search PubMed, Embase, Web of science for studies assessing the differences in RNFL measured by OCT between patients with migraine and healthy controls. Case-control studies published in English will be included. Two reviewers will independently screen eligible articles, extract data, and assess quality. This meta-analysis will synthesize selected research data and compare the difference in RNFL thickness between patients with migraine and healthy controls. We will use Stata 15 in this meta-analysis. I statistics will be used to assess heterogeneity. If I ≤ 50%, the data are synthesized will use a fixed effect model. Otherwise, a random effect model will be performed. Publication bias will be determined by the Egger test. The methodological quality of all included studies will be evaluated by the Newcastle-Ottawa Scale (NOS). We will perform subgroup analysis, sensitivity analysis, and meta-regression analysis to test the robustness of the results.

RESULTS

We will obtain quantitative results regarding the difference in RNFL thickness between migraine patients and healthy controls. The results will be published in a peer-reviewed journal.

CONCLUSIONS

The results of this study provide a high-quality synthesis of existing evidence and provide a basis for assessing the effect of migraine on the thickness of RNFL.

REGISTRATION NUMBER

INPLASY 202060033.

Changes in Retinal OCT and Their Correlations with Neurological Disability in Early ALS Patients, a Follow-Up Study

BACKGROUND

To compare early visual changes in amyotrophic lateral sclerosis (ALS) patients with healthy controls in a baseline exploration, to follow-up the patients after 6 months, and to correlate these visual changes with neurological disability.

METHODS

All patients underwent a comprehensive neurological and ophthalmological examination. A linear mixed analysis and Bonferroni p-value correction were performed, testing four comparisons as follows: Control baseline vs. control follow-up, control baseline vs. ALS baseline, control follow-up vs. ALS follow-up, and ALS baseline vs. ALS follow-up.

RESULTS

The mean time from the diagnosis was 10.80 ± 5.5 months. The analysis of the optical coherence tomography (OCT) showed: (1) In ALS baseline vs. control baseline, a macular significantly increased thickness of the inner macular ring temporal and inferior areas; (2) in ALS follow-up vs. ALS baseline, a significant macular thinning in the inner and outer macular ring inferior areas; (3) in ALS follow-up vs. ALS baseline, a significant peripapillary retinal nerve fiber layer (pRNFL) thinning in the superior and inferior quadrants; and (4) ALS patients showed a moderate correlation between some OCT pRNFL parameters and Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R) score.

CONCLUSION

The OCT showed retinal changes in patients with motoneuron disease and could serve as a complementary tool for studying ALS.

Imaging in Neuro-ophthalmology

PURPOSE OF REVIEW

This article discusses an approach to imaging in patients with neuro-ophthalmologic disorders, with emphasis on the clinical-anatomic localization of lesions affecting afferent and efferent visual function.

RECENT FINDINGS

Advances in MRI, CT, ultrasound, and optical coherence tomography have changed how neuro-ophthalmic disorders are diagnosed and followed in the modern clinical era.

SUMMARY

The advantages, disadvantages, and indications for various imaging techniques for neuro-ophthalmologic disorders are discussed, with a view to optimizing how these tools can be used to enhance patient care.