Contrast Sensitivity Is Associated With Chorioretinal Thickness and Vascular Density of Eyes in Simple Early-Stage High Myopia

A Novel Artificial Intelligence-Based Classification of Highly Myopic Eyes Based on Visual Function and Fundus Features

Purpose

To develop a novel classification of highly myopic eyes using artificial intelligence (AI) and investigate its relationship with contrast sensitivity function (CSF) and fundus features.

Methods

We enrolled 616 highly myopic eyes of 616 patients. CSF was measured using the quantitative CSF method. Myopic macular degeneration (MMD) was graded according to the International META-PM Classification. Thickness of the macula and peripapillary retinal nerve fiber layer (p-RNFL) were assessed by fundus photography and optical coherence tomography, respectively. Classification was performed by combining CSF and fundus features with principal component analysis and k-means clustering.

Results

With 83.35% total variance explained, highly myopic eyes were classified into four AI categories. The percentages of AI categories 1 to 4 were 14.9%, 37.5%, 36.2%, and 11.4%, respectively. Contrast acuity of the eyes in AI category 1 was the highest, which decreased by half in AI category 2. For AI categories 2 to 4, every increase in category led to a decrease of 0.23 logarithm of the minimum angle of resolution in contrast acuity. Compared with those in AI category 1, eyes in AI category 2 presented a higher percentage of MMD2 and thinner temporal p-RNFL. Eyes in AI categories 3 and 4 presented significantly higher percentage of MMD ≥ 3, thinner nasal macular thickness and p-RNFL (P < 0.05). Multivariate regression showed AI category 4 had higher MMD grades and thinner macular compared with AI category 3.

Conclusions

We proposed an AI-based classification of highly myopic eyes with clear relevance to visual function and fundus features.

Translational Relevance

This classification helps to discover the early hidden visual deficits of highly myopic patients, becoming a useful tool to evaluate the disease comprehensively.

Contrast Sensitivity Better Reflects Wide-Field Swept-Source Optical Coherence Tomography Angiography Vascular Metrics Among Healthy Eyes Compared to Visual Acuity

BACKGROUND AND OBJECTIVE

To evaluate the association between widefield swept-source optical coherence tomography angiography (WF SS-OCTA) and visual function in healthy eyes.

PATIENTS AND METHODS

Fifty-seven eyes of 45 patients were evaluated with visual acuity (VA), contrast sensitivity (CS), and WF SS-OCTA (3 × 3, 6 × 6, and 12 × 12 mm images) on the same day. Mixed-effects multivariable regression analyses were performed.

RESULTS

Contrast sensitivity metrics, including CS between 6 to 18 cycles per degree (cpd) and area under the logarithm CS function, were significantly associated with vessel density (VD) and vessel skeletonized density (VSD), whereas VA was not. The largest effect size was between CS at 18 cpd and VD (β = 0.41, P = 0.007) and VSD (β = 0.42, P = 0.006) on 12 × 12 mm images.

CONCLUSIONS

Reduced VSD and VD on WF SSOCTA was significantly associated with decreased CS, whereas VA was not. These results suggest CS could serve as a screening tool for early stage retinal and neurologic disorders. [Ophthalmic Surg Lasers Imaging Retina 2024;55:494-502.].

Association between contrast sensitivity function and structural damage in primary open-angle glaucoma

AIMS

To evaluate the association between contrast sensitivity function (CSF) and glaucomatous structural damage in primary open-angle glaucoma (POAG).

METHODS

A cross-sectional study was performed with 103 patients (103 eyes) aged 25-50 years who had POAG without any other ocular disease. CSF measurements were obtained by the quick CSF method, a novel active learning algorithm that covers 19 spatial frequencies and 128 contrast levels. The peripapillary retinal nerve fibre layer (pRNFL), macular ganglion cell complex (mGCC), radial peripapillary capillary (RPC) and macular vasculature were measured by optical coherence tomography and angiography. Correlation and regression analyses were used to assess the association of area under log CSF (AULCSF), CSF acuity and contrast sensitivities at multiple spatial frequencies with structural parameters.

RESULTS

AULCSF and CSF acuity were positively associated with pRNFL thickness, RPC density, mGCC thickness and superficial macular vessel density (p<0.05). Those parameters were also significantly associated with contrast sensitivity at 1, 1.5, 3, 6, 12, 18 cycles per degree spatial frequencies (p<0.05) and, the lower the spatial frequency, the higher the correlation coefficient. RPC density (p=0.035, p=0.023) and mGCC thickness (p=0.002, p=0.011) had significant predictive value for contrast sensitivity at 1 and 1.5 cycles per degree, with adjusted R 2 of 0.346 and 0.343, respectively.

CONCLUSIONS

Full spatial frequency contrast sensitivity impairment, most notably at low spatial frequencies, is a characteristic change in POAG. Contrast sensitivity is a potential functional endpoint for the measurement of glaucoma severity.

Reduced contrast sensitivity function is correlated with changes to cone photoreceptors in simple high myopia

Purpose

To investigate the contrast sensitivity function (CSF) changes in simple high myopia (SHM) and evaluate the correlations between these changes with the early changes in the retinal microstructure.

Methods

This prospective study comprised 81 subjects, 20 with emmetropia (EM), 26 with low myopia and moderate myopia (LM/MM), and 35 with SHM. The area under the log CSF curve (AULCSF) and the cut-off spatial frequency (Cut-off SF) were employed as measures of CSF. Adaptive optics (AO) was employed to quantify the cone density, spacing, and regularity. The thickness and blood flow of the retinal sublayers were determined from vertical and horizontal optical coherence tomography angiography (OCTA) A-scans. Swept-source optical coherence tomography (SS-OCT) was employed to analyze the choroidal thickness (CT) and choroidal vascularity using a custom algorithm. Differences in the retinal and choroidal parameters, cone distribution, AULCSF, and Cut-off SF were compared among the three groups. Multivariate linear mixed models were used to elucidate the associations between photoreceptor morphological alterations, retinal and choroidal parameters, and AULCSF.

Results

The AULCSF and Cut-off SF were significantly lower in the SHM group compared to the EM and LM groups (p < 0.05). The SHM group had less cone density, larger cone spacing, and lower cone regularity than the EM and LM/MM groups (p < 0.05). Moreover, the thickness of the inner segment of photoreceptors (IS), retinal pigment epithelium (RPE) layer and choroid were reduced, and the outer segment of photoreceptors (OS) was thicker in the SHM group compared to the EM and LM/MM groups (all p < 0.05). A longer axial length (AL) was correlated with decreased AULCSF, cone density, and cone spacing (r = -0.800 to 0.752, all p < 0.050). Additionally, decreased CSF was correlated with lower cone density (r = 0.338, p = 0.035).

Conclusion

Decreased contrast sensitivity was observed in patients with SHM and cone density was significantly correlated with reduced AUCSF.

Association between Fundus Tessellation and Contrast Sensitivity in Myopic Eyes

PURPOSE

To assess the association of fundus tessellation with contrast sensitivity, Quality of Vision questionnaire, and other factors at five years postcorneal refractive surgery.

METHODS

This is a cross-sectional study. Both eyes of 98 subjects (196 eyes) who received femtosecond laser in situ keratomileusis (FS-LASIK) or small incision lenticular extraction (SMILE) five years prior were enrolled in this study. Fundus tessellation was imaged using wide-angle fundus photographs and graded into four categories with the assistance of the ETDRS grid. Photopic and mesopic contrast sensitivity were measured under the best correction. The Quality of Vision (QoV) questionnaire was used to assess visual symptoms.

RESULTS

Fundus tessellation was classified as follows: 19 eyes were grade 0 (9.7%), 28 eyes were grade 1 (14.3%), 59 eyes were grade 2 (30.1%), and 90 eyes were grade 3 (45.9%). Higher degrees of fundus tessellation were associated with lower photopic contrast sensitivity, a significant difference was observed at spatial frequencies of 6cpd (p = 0.030, grade 1 >grade 3 p = 0.011). Higher degrees of fundus tessellation were also associated with lower mesopic contrast sensitivity, a significant difference was observed at spatial frequencies of 18cpd (p = 0.011, grade 0 >grade 3 p = 0.012). The preoperative degree of myopia was positively associated with fundus tessellation grade (p < 0.001). However, in linear mixed-effect model analysis, no significant influence of parameters (contrast sensitivity, preoperative myopia, and QoV scores) upon different tessellation grades was found (p > 0.05).

CONCLUSIONS

Patients with moderate and high myopia were more likely to have higher grades of fundus tessellation. Higher degree of fundus tessellation associates with lower contrast sensitivity. Patients with moderate and high myopia should be concerned with retinal-choroidal changes. Contrast sensitivity could be a clinical sign for progression of tessellation and used to screen for early retinal-choroidal changes to prevent pathologic myopia.

Can children measure their own vision? A comparison of three new contrast sensitivity tests

PURPOSE

To investigate the feasibility of children measuring their own contrast sensitivity using a range of tablet- and paper-based tests.

METHODS

Forty children aged 5-15 years with amblyopia (N = 10), bilateral vision impairment (N = 10) or good vision (N = 20) measured their own vision on a screen-based optotype test (Manifold), a gamified vision test (PopCSF) and a paper-based test (Spotchecks) in a laboratory with minimal supervision. Completion rate, test-retest repeatability, test duration and participants' preferences were recorded for each test.

RESULTS

Most participants (36/40) were able to perform all three tests. All tests were correlated with clinically measured visual acuity and contrast sensitivity (p < 0.001). The 95% coefficient of repeatability was 0.30 dB for Manifold, 0.29 dB for PopCSF and 0.13 dB for Spotchecks. All tests differentiated between children with reduced contrast sensitivity and control participants. PopCSF and Spotchecks were also able to differentiate between children with amblyopia and those with good vision. Median test time was 152, 130 and 202 s for Manifold, PopCSF and Spotchecks, respectively. Twenty-two participants preferred the PopCSF test, 10 preferred Spotchecks and 6 preferred Manifold. Thirty-nine out of the 40 children (98%) said they would measure their own vision at home using at least one of these tests every month.

CONCLUSIONS

Children and young people can test their own contrast sensitivity with repeatable results. Of these three tests, the most repeatable was Spotchecks, the quickest was PopCSF and participants' favourite was PopCSF. Nearly all of the participants said they would be willing to use at least one of the three tests at home.

Optical coherence tomography enhanced depth imaging of chorioretinal folds in patients with orbital tumors

AIM

To characterize spectral-domain optical coherence tomography (SD-OCT) features of chorioretinal folds in orbital mass imaged using enhanced depth imaging (EDI).

METHODS

Prospective observational case-control study was conducted in 20 eyes of 20 patients, the uninvolved eye served as a control. All the patients underwent clinical fundus photography, computed tomography, EDI SD-OCT imaging before and after surgery. Two patients with cavernous hemangiomas underwent intratumoral injection of bleomycin A5; the remaining patients underwent tumor excision. Patients were followed 1 to 14mo following surgery (average follow up, 5.8mo).

RESULTS

Visual acuity prior to surgery ranged from 20/20 to 20/200. Following surgery, 5 patients' visual acuity remained unchanged while the remaining 15 patients had a mean letter improvement of 10 (range 4 to 26 letters). Photoreceptor inner/outer segment defects were found in 10 of 15 patients prior to surgery. Following surgical excision, photoreceptor inner/outer segment defects fully resolved in 8 of these 10 patients.

CONCLUSION

Persistence of photoreceptor inner/outer segment defects caused by compression of the globe by an orbital mass can be associated with reduced visual prognosis. Our findings suggest that photoreceptor inner/outer segment defects on EDI SD-OCT could be an indicator for immediate surgical excision of an orbital mass causing choroidal compression.

Reduced contrast sensitivity function correlated with superficial retinal capillary plexus impairment in early stage of dysthyroid optic neuropathy

BACKGROUND

To assess the accuracy of contrast sensitivity function (CSF) in detecting dysthyroid optic neuropathy (DON) at an early stage in thyroid-associated ophthalmopathy (TAO) patients and to examine potential factors that may be linked to early visual impairments in these individuals.

METHODS

A total of 81 TAO patients (50 non-DON and 31 DON), and 24 control subjects participated in the study. CSF was measured with the quick CSF (qCSF) method. Optical coherence tomography angiography (OCTA) images of the ganglion cell complex layer (GCCL), superficial and deep retinal capillary plexuses (SRCP and DRCP) in a 3 mm diameter area around the macula were evaluated.

RESULTS

Compared with the controls, the area under the log contrast sensitivity function (AULCSF) and SRCP density were significantly reduced in non-DON and DON patients (all P < 0.05). The GCCL thickness of the DON patients was thinner than that of the controls and non-DON patients (all P < 0.05). The AULCSF was significantly correlated with spherical equivalent refractive error, muscle index, SRCP density and GCCL thickness in TAO patients, respectively (all P < 0.05). However, stepwise multi-regression analysis showed that the AULCSF was only significantly correlated with SRCP density (P < 0.001). Receiver operating characteristic curve analysis showed that the AULCSF produced the most accurate discrimination between non-DON and DON patients from the controls (AUC = 0.831, 0.987, respectively; all P < 0.001).

CONCLUSIONS

CSF change in the early stage of DON is related to SRCP density. It can be an early indicator of visual impairments associated with DON in TAO patients.

The Characteristics of Quick Contrast Sensitivity Function in Keratoconus and Its Correlation with Corneal Topography

INTRODUCTION

To characterize quick contrast sensitivity function (qCSF) in keratoconus and its correlation with corneal topographic parameters.

METHODS

Patients with keratoconus (n = 120) who visited the Fudan Eye and ENT Hospital between April and June 2021 were enrolled in our study. A total of 215 eyes were subdivided into three groups according to maximum keratometry (K_max): Group 1 (K_max ≤ 48 D, 74 eyes), Group 2 (48 D < K_max ≤ 55 D, 64 eyes), and Group 3 (K_max > 55 D, 77 eyes). Manifest refraction, best corrected distance visual acuity (BCVA), corneal topography, and the qCSF test were examined. Intergroup comparisons and correlations among various corneal topographic parameters and qCSF were analyzed.

RESULTS

Significant differences in the area under the log CSF (AULCSF) and CSF Acuity among the three groups were found, which decreased with an increase in K_max. Contrast sensitivity (CS) between spatial frequencies of 3.0 to 18.0 cpd was significantly different (all P < 0.05) between Groups 1 and 2. The CS at all spatial frequencies was significantly different (all P < 0.05) between Group 3 and other two groups. At 3.0-18.0 cpd, CS decreased significantly (all P < 0.05) in Groups 1-3. Manifest refraction and topographic indices correlated significantly with qCSF parameters (all P < 0.05). Multivariable linear regression analysis showed that cylindrical refraction, logMAR BCVA, and index of surface variance had good predictive values for AULCSF and CSF Acuity.

CONCLUSIONS

The use of qCSF test can serve as a feasible tool to evaluate visual quality and severity of keratoconus, since changes in CS significantly correlated with keratoconus severity.

Effect of macular vascular density on visual quality in young myopic adults

Objective

To evaluate macular vascular density using optical coherence tomography angiography (OCTA) and to investigate its impact on best-corrected visual acuity (BCVA), contrast sensitivity function (CSF), and higher-order aberrations (HOAs) in young myopic adults.

Methods

This cross-sectional study included 109 eyes with axial length (AL) between 22 and 26 mm in the medium AL group and 90 eyes with AL > 26 mm in the long AL group. OCTA was used to obtain 3 × 3 mm en face images, and the vessel length density (VLD), perfusion density (PD), and fovea avascular zone (FAZ) of the superficial layer were evaluated. Visual quality was assessed using the CSF and HOAs.

Results

Significant differences were found in the inferior VLD, parafoveal PD, and FAZ areas between the groups. AL and macular vascular density showed negative correlations in the inferior and nasal areas. The spherical correction (SE) also showed a positive correlation with vascular density in these two areas. FAZ area and perimeter had a significant negative association with AL, and FAZ circularity was correlated with SE. CSF with bright around 6 and 12 spatial frequencies showed positive correlations with nasal PD. The parafoveal PD showed a significant correlation with BCVA after adjusting for other factors.

Conclusion

The superficial macular vascular density of young myopic adults decreased with lower SE and longer AL in the parafovea area. An eye with a long AL has a smaller FAZ, and myopia decreases the FAZ circularity index. The decrease in vessel density could contribute to worse BCVA and may be correlated with lower CSF, but not with HOAs.