Relationship Between the Shift of the Retinal Artery Associated With Myopia and Ocular Response Analyzer Waveform Parameters

Advanced ultrawide-field optical coherence tomography angiography identifies previously undetectable changes in biomechanics-related parameters in nonpathological myopic fundus

Purpose: To detect previously undetectable changes in vessel density and structural thickness, the two biomechanics-related parameters reflecting hemodynamics and tensile strength, respectively, in the peripheral and central fundi of nonpathological myopic eyes with an advanced ultrawide-field optical coherence tomography angiography (OCTA) system.

Methods: A cross-sectional observational clinical study was carried out by recruiting 155 eyes from 79 college students aged 18–28 years. The eyes were stratified into normal, low-myopia, medium-myopia, and high-myopia groups according to diopter. A newly developed OCTA system with scanning dimensions of 24 mm × 20 mm, acquisition speed of 400 kHz, and imaging range of 6 mm was used to examine the vessel densities of superficial vascular complex (SVC), deep vascular complex (DVC), choriocapillary (ChC), and choroidal vessel (ChV) layers, as well as the thicknesses of the inner retina, outer retina, and choroid in the nonpathological myopic eyes.

Results: The vessel densities in ChV at the temporal, inferotemporal, inferior, and inferonasal regions in the fundus periphery were significantly reduced in myopic subjects as compared to normal controls (all p < 0.05). The thicknesses of the inner retinal segments in most peripheral regions of the fundus became attenuated along with myopia severity (all p < 0.05). The thicknesses of the outer retinal segments were diminished at the superior and supranasal regions of the peripheral fundi of myopic subjects as compared to normal controls (all p < 0.05). At the central macular region, the decreased vessel densities of SVC and DVC were correlated with the attenuated thicknesses of inner retinal segments, respectively (all p < 0.05).

Conclusion: As revealed for the first time by the advanced ultrawide-field OCTA system, the two biomechanics-related parameters that include the densities of the choroidal vessels and thicknesses of the inner retina segments were significantly reduced in the periphery of nonpathological myopic fundi and the reductions were associated with myopia severity. At the central macular region, the newly developed device provides consistent results with the previous findings. Therefore, it is important to use the noninvasive, ultrawide-field OCTA with high resolution for early detection of fundus changes in subjects with nonpathological high myopia.

Clinical Trial Registration: clinicaltrials.gov, identifier ChiCTR2100054093.

Retinal vessel shift and its association with axial length elongation in a prospective observation in Japanese junior high school students

PURPOSE

To investigate retinal vessel shift (RVS) and its association with axial length (AL) elongation in junior high school students.

METHODS

Total 161 eyes of 161 healthy junior high school students were prospectively studied. Optical AL and anterior chamber depth (ACD) measurements, and fundus photography were performed in the first and third grades. Eyes of subjects in the first and third grade that had perfect matching among all the retinal vessels were allocated to the RVS(-) group, otherwise allocated to the RVS(+) group. In the RVS(+) group, the peripapillary retinal arteries angle (PRAA) was measured for quantitative analysis of RVS; the angle between the major retinal arteries. The variables related to PRAA were identified using model selection with the corrected Akaike information criterion.

RESULTS

Forty-two eyes (26.1%) were allocated to the RVS(+) group. There were seven patterns in the RVS of those in the RVS(+) group, including clockwise shift in the supra temporal area (5 eyes), infra temporal area (7 eyes), and nasal area (9 eyes); anticlockwise shift in the supra temporal area (7 eyes), infra temporal area (5 eyes), and nasal area (2 eyes); and distal shift in the temporal area (7 eyes). The optimal model for the PRAA narrowing included larger AL and body weight in the first grade, and greater AL elongation.

CONCLUSION

Various (seven) RVS patterns were observed in about 25% of the junior high school students within two years. RVS was associated with AL elongation, and useful to reveal the mechanism of myopic retinal stretch.

Relationship Between Macular Ganglion Cell Thickness and Ocular Elongation as Measured by Axial Length and Retinal Artery Position

Purpose

We recently reported on the usefulness of retinal artery trajectory in estimating the magnitude of retinal stretch due to myopia. The purpose of the present study was to elucidate the relationship between the peripapillary retinal artery angle (PRAA) and thickness of the macular ganglion cell–inner plexiform layer (GCIPL).

Methods

This r included 138 healthy eyes of 79 subjects older than 20 years of age without any known eye disease. GCIPL thickness was separated into eight sectors according to quadrant and eccentricity from the fovea. The PRAA was calculated as the angle between the superior and inferior retinal arteries. Relationships between whole GCIPL thickness (average and sectorial) and the values of PRAA and axial length (AL) were investigated using a linear mixed model.

Results

Average GCIPL thickness in the whole scanned area decreased significantly with narrowing of the PRAA with and without adjusting for AL. Sectorized macular GCIPL thickness also decreased significantly, with narrowing of the PRAA in seven out of the eight with the adjustment of AL, the exception being the inferior peripheral temporal sector.

Conclusions

Macular GCIPL thickness decreased significantly with narrowing of the PRAA on average and in seven out of eight sectors.

Visualizing the dynamic change of Ocular Response Analyzer waveform using Variational Autoencoder in association with the peripapillary retinal arteries angle

The aim of the current study is to identify possible new Ocular Response Analyzer (ORA) waveform parameters related to changes of retinal structure/deformation, as measured by the peripapillary retinal arteries angle (PRAA), using a generative deep learning method of variational autoencoder (VAE). Fifty-four eyes of 52 subjects were enrolled. The PRAA was calculated from fundus photographs and was used to train a VAE model. By analyzing the ORA waveform reconstructed (noise filtered) using VAE, a novel ORA waveform parameter (Monot1-2), was introduced, representing the change in monotonicity between the first and second applanation peak of the waveform. The variables mostly related to the PRAA were identified from a set of 41 variables including age, axial length (AL), keratometry, ORA corneal hysteresis, ORA corneal resistant factor, 35 well established ORA waveform parameters, and Monot1-2, using a model selection method based on the second-order bias-corrected Akaike information criterion. The optimal model for PRAA was the AL and six ORA waveform parameters, including Monot1-2. This optimal model was significantly better than the model without Monot1-2 (p = 0.0031, ANOVA). The current study suggested the value of a generative deep learning approach in discovering new useful parameters that may have clinical relevance.

Correlation Between the Myopic Retinal Deformation and Corneal Biomechanical Characteristics Measured With the Corvis ST Tonometry

Purpose

We previously reported that the retinal deformation due to myopia was represented by the peripapillary retinal arteries angle (PRAA). In this study, we investigated the relationship between the PRAA and biomechanical properties measured with Corvis ST (CST) tonometry.

Methods

Thirty-four normative eyes of 34 subjects who underwent CST measurement were enrolled. The PRAA was calculated from a fundus photograph. Variables related to the PRAA were identified from age, axial length, spherical equivalent refractive error, and 10 CST parameters using model selection with the second-order bias-corrected Akaike information criterion index.

Results

The PRAA was best described with axial length (coefficient = −5.66, P < 0.0001), maximum deflection amplitude (mm; coefficient = 130.5, P = 0.0004), and deflection amplitude ratio (DA ratio) 2 mm (coefficient = −25.8, P = 0.0032), where mm was the amount of the maximum corneal apex movement and DA ratio 2 mm was the ratio between the deformation amplitudes at the apex and 2 mm away from the apex. The optimal model was significantly better than the model only with axial length (P = 0.0014, analysis of variance).

Conclusions

The PRAA was significantly better described with the CST parameters compared to the axial length model only; eyes with small PRAA (larger myopic retinal deformation) showed narrow and shallow maximum corneal deflection.

Translational Relevance

The Corvis ST parameters, which represents corneal biomechanical characteristics, were associated with myopic retinal deformation.