Association of choroidal thickness and blood flow features with asymmetric axial lengths in children with unilateral myopic anisometropia.

BACKGROUND: Considering that changes in the choroidal thickness are closely related to ocular growth, we studied the choroidal thickness (CT) and the blood flow features in children with unilateral myopic anisometropia (UMA) as well as investigating the relationship between choroidal changes and myopia. METHODS: Subjective refractive, axial length (AL), and biometric parameters were measured in 98 UMA children (age: 8-15 years). CT and choroidal blood-flow features, including the choroidal vessel volume (CVV), choroidal vascularity index (CVI), and choriocapillaris perfusion area (CCPA), were measured through swept-source optical coherence tomography angiography. The macular region was categorized into four concentric circles of diameters 0-1 mm (central fovea), 1-3 mm (parafovea), 3-6 mm (perifovea), and 6-9 mm (extended), and further categorized into superior (S), inferior (I), temporal (T), and nasal (N) quadrants. RESULTS: The aforementioned four regions of myopic eyes displayed significantly lower CT, CVV, and CVI than those of non-myopic eyes. CCPA changes differed across different regions of both the eyes (parts of N and T quadrants). There was an inverse association between CT and the interocular AL difference (central and other regions S, T quadrant). No correlation was noted between CVV and CVI with interocular AL difference. CT and CVV were positively correlated in the 0-6-mm macular region of myopic eyes (Spearman correlation coefficient = 0.763, P < 0.001). CONCLUSIONS: In UMA children, CCT and blood flow may be related to myopia progression. A robust correlation between CT and CVV in the 0-6-mm macular region and reduced CT and diminished blood flow indicated an association with myopia.

Assessment of the effects of myopic and hyperopic anisometropia on choroidal vascular structure in children using SS-OCTA.

OBJECTIVE: To compare large- and medium-sized choroidal vascularity and the choriocapillaris (CC) flow area in children with different refractive errors using swept-source optical coherence tomography angiography (SS-OCTA). METHODS: Forty-two anisometropic children were enrolled and divided into hyperopic anisometropia (HA) and myopic anisometropia (MA) groups. SS-OCTA was performed to analyse choroidal vascularity. Mean choroidal thickness (CT), choroidal vascularity volume (CVV), choroidal vascularity index (CVI) and CC flow area were compared between the two eyes. The inter-ocular differences between the two groups were also determined. RESULTS: Mean CT and CVV were highest in eyes with shorter axial lengths in both refractive groups, and the difference between the two eyes was positively correlated with the difference in axial length at the foveal region. Significant differences in the CVI in the MA group were only found in the parafoveal region. Inter-ocular differences in the CC were significantly reduced in eyes with longer axial lengths in the foveal and parafoveal regions of the HA and MA groups, respectively. Comparing inter-ocular differences, CC was significantly greater in the parafoveal region of the MA group than the HA group. CONCLUSIONS: All layers of choroidal vasculature were thinner in eyes with longer axial lengths in all groups. The inter-ocular CC difference was greater in the MA than in the HA group, with similar differences in axial length. This suggests that both medium-to-large choroidal vascular and choroidal capillaries may play a role in myopia development.

[Differential Analysis of Macular Structure and Microcirculation in Both Eyes of Patients With Myopic Anisometropia].

Objective To compare the macular structure and microcirculation in both eyes of the patients with myopic anisometropia.Methods Optical coherence tomography angiography(OCTA)was employed to scan the macular areas in both eyes of 44 patients with myopic anisometropia.The patients were assigned into high and low groups based on the refractive diopter,and the parameters such as retinal thickness,choroidal thickness,vascular density,and perfusion density in the macular areas of both eyes were compared between the two groups.Results Other macular areas except the central and external nasal areas and the choroid of the fovea in the high group were thinner than those in the low group(all P<0.05).There was no statistically significant difference in retinal vascular density or perfusion density in different areas between the two groups(all P>0.05).Conclusion In the patients with myopic anisometropia,most areas of the retina in the case of high myopia is thinner than that in the case of low myopia,while there is no difference in retinal vascular density or perfusion density in both eyes.

Ten-Year Outcomes of LASIK for Pediatric Myopic Anisometropia.

Purpose: To evaluate long-term safety, effectiveness, and stability of unilateral LASIK in pediatric myopic anisometropic amblyopia. Methods: This retrospective study included children who received unilateral LASIK for myopic anisometropia of >6 D, after mandatory 6-month occlusion/penalization therapy. They were evaluated at 6 months, 1 year, 2 years and biannually until 10 years. Outcome measures included visual acuity, refraction, ocular alignment, stereopsis, corneal clarity, and corneal topography. Results: 32 patients (16 girls) with mean age of 8.6 ± 2.3 years completed 10 years of follow up after unilateral LASIK. Mean preoperative spherical equivalent refraction (SER) was -10.3D ±2.0D in the affected eye, with anisometropic difference of -9.5D ±1.7D. Mean post-LASIK SER was -1.3D±0.8D (p<0.001). Anisometropia significantly decreased to 0.3D±0.8D, 0.4D±1.0D, and 1.0±2.5D at 6 months, 1 year and 10 years respectively (p<0.001). 11 patients (34%) who had preoperative intermittent exotropia (< 15°) regained orthophoria in all gazes, while 5 of 10 who had constant exotropia with large angle (>30°) required strabismus surgery for ocular alignment. BCVA improved from 0.04±0.6 Decimal at baseline to 0.6 ±0.2 after LASIK and occlusion therapy (p< 0.001). Despite insignificant refractive regression in both eyes, patients have maintained orthophoria, improved stereopsis, clear cornea, and the topography showed no evidence of post-LASIK ectasia. Conclusion: LASIK appears safe, effective, and stable for correcting refractory pediatric myopic anisometropia, in which conventional measures fail or endanger normal visual development. Eliminating anisometropic aniseikonia consequently restores binocular vision and stereopsis which, along with amblyopia therapy, would reverse amblyopia and prevent recurrence.

Corneal morphological changes after small incision lenticule extraction for myopic anisometropia.

Purpose: This research aims to study the corneal morphological changes in adult patients with myopic anisometropia after small incision lenticule extraction (SMILE) and the safety, efficacy, and predictability of clinical outcomes. Methods: This was a prospective cohort study. Patients with myopic anisometropia [refractive difference >2.0 diopters (D)] were included in this study who underwent SMILE at our hospital from September 2019 to March 2021. For the two eyes of each patient, the one with higher myopia was defined as group A, and the fellow eye was group B. The follow-up time points were set as 1 week, 1 month, 3 months, and 6 months after the surgery. The data collected were uncorrected and best-corrected distance visual acuity (UDVA and CDVA), spherical equivalent (SE), efficacy and safety indexes, posterior corneal elevation (PCE), anterior and posterior corneal radius of curvature in the 3 mm area at the center of the thinnest point of the cornea (ARC and PRC), and higher-order aberrations (HOAs). Results: The study included 36 patients (72 eyes), and the mean age was 25.2 ± 6.4 years. The preoperative SEs were -6.45 ± 1.25 D in group A and -3.76 ± 1.29 D in group B. Six months after surgery, the SEs in groups A and B were -0.09 ± 0.50 D and 0.07 ± 0.47 (P = 0.059), respectively. The efficacy indexes were 1.06 ± 0.16 in group A and 1.07 ± 0.14 in group B (P = 0.750). The safety indexes were 1.08 ± 0.14 in group A and 1.12 ± 0.15 in group B (P = 0.173). The PCE was significantly reduced at 6 months after surgery in pagebreak both groups (P < 0.05). The ARC was significantly higher than before the surgery (P < 0.05) in the two groups. The two groups showed significant increases in total HOAs, coma 90°, and spherical aberrations (P < 0.05). Conclusion: SMILE is predictable, effective, and safe in correcting myopic anisometropia. The postoperative changes in HOAs are characteristic.

Choroidal thickness and choriocapillaris vascular density in myopic anisometropia.

BACKGROUND: This study aims to examine interocular differences in the choroidal thickness and vascular density of the choriocapillaris in anisometropic myopes and to further explore the relationship between choroidal blood flow and myopia. METHODS: The sample comprised 44 participants with anisometropic myopia, aged 9 to 18 years, with normal best-corrected visual acuity. All participants underwent a series of examinations, including spherical equivalent refraction (SER) and axial length (AL), measured by a Lenstar optical biometer and optical coherence tomography angiography (OCTA) scanner. OCT measured the choroidal thickness, vascular density, and flow voids of the choriocapillaris, and a customized algorithm was implemented in MATLAB R2017a with the post-correction of AL. The choroidal thickness was measured at the fovea and 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 mm nasally, temporally, inferiorly, and superiorly to the fovea. The vascular density and the flow voids of the choriocapillaris were measured at a 0.6-mm-diameter central circle, and the 0.6-2.5 mm diameter circle in the nasal, temporal, inferior, and superior regions. Repeated-measured ANOVAs were used to analyze the interocular differences. Partial correlations with the K value and age adjustments were used to study the relationships between the choroidal thickness, the choriocapillaris vascular density and flow voids, the SER and AL. RESULTS: The choroidal thickness of the more myopic eyes was significantly thinner than less myopic eyes (P ≤ 0.001), and the flow voids in the more myopic eyes were more than less myopic eyes (P = 0.002). There was no significant difference in the vascular density of the choriocapillaris between the more and less myopic eyes (P = 0.525). However, when anisometropia was more than 1.50 D, the vascular density of choriocapillaris in the more myopic eyes was significantly less than the less myopic eyes (P = 0.026). The interocular difference of the choroidal thickness was significantly correlated with the interocular difference in SER and AL in the center, superior, and inferior regions but not in the nasal or temporal regions. The interocular differences of the vascular density and the flow voids of the choriocapillaris were not correlated with the interocular difference of SER and AL. CONCLUSIONS: The choroidal thickness is thinner in the more myopic eyes. The flow void is increased, and the vascular density of the choriocapillaris is reduced in the more myopic eyes of children with anisometropia exceeding 1.50 D.

Regional analysis of segmented-macular structure in patients with myopic anisometropia.

PURPOSE: To compare intraretinal layers between the eyes in patients with myopic anisometropia, and evaluate the relationship between the layers with spherical equivalent (SE) and axial length (AL). METHODS: In this retrospective study, the more myopic (MM) and fellow (F) eyes of 41 patients with myopic anisometropia, and 38 emmetropic (± 0.50 diopter) control (C) eyes were inclueded. Intraretinal layer segmentation was performed by optical coherence tomography. Global volumes of retinal layers and their thicknesses in nine macular regions were compared. Correlation analysis was used to determine the relationship with SE and AL in each layer. RESULTS: Total retinal, ganglion cell (GCL), inner nuclear (INL), and outer plexiform (OPL) layer volumes in MM eyes were less than in C eyes, while INL and OPL were less than in F eyes. There was no difference in the fovea, except for the retinal pigment epithelium. In MM eyes, only INL and OPL were thin in at least one perifoveal and parafoveal quadrant compared to F eyes. Only INL and OPL thicknesses were significantly correlated with both SE and AL in all perifoveal quadrants. In contrast to the thinning found in MM eyes, the only layer in which thickening was detected to compare to C eye was nerve fiber layer (NFL), which correlated positively with SE and negatively with AL. CONCLUSION: While the fovea is less affected by myopia, thinning becomes remarkable in the perifoveal quadrants. Despite thinning in many layers, especially INL and OPL, NFL thickening may be seen due to myopia.

Static and Dynamic Pupil Characteristics in Myopic Anisometropic Amblyopia.

OBJECTIVES: The purpose of this study was to compare static and dynamic pupillometry measurements in patients with myopic anisometropic amblyopia with those of age-matched, healthy subjects. METHODS: This prospective, cross-sectional study consisted of 29 patients with myopic anisometropic amblyopia and 83 control subjects. While both the amblyopic eye and the fellow eye of patients with myopic anisometropic amblyopia were examined, data were only recorded for the right eye of the subjects in the control group. Static pupillometry measurements determined included the scotopic pupil diameter (PD), mesopic PD, low photopic PD, and high photopic PD. Subsequently, dynamic pupillometry measurements were obtained, including the resting diameter, amplitude of pupil contraction, latency of pupil contraction, duration of pupil contraction, velocity of pupil contraction, latency of pupil dilation, duration of pupil dilation, and velocity of pupil dilation. RESULTS: In the myopic anisometropia patients, there was a statistically significant difference in the low photopic PD and high photopic PD values of the amblyopic eyes and the corresponding fellow eyes compared with the healthy subjects (p<0.05 for each). These parameters of low photopic PD and high photopic PD were similar between the highly myopic eyes and the fellow eyes. There was no statistically significant difference in the mesopic or scotopic PD values between any of the groups (p>0.05 for each). There were no significant differences in the dynamic pupillometric measurements between the study and control eyes. CONCLUSION: These results confirm that amblyopia is a binocular disorder. The dynamic pupillary responses were similar in the highly myopic and fellow eyes, indicating that evaluation of relative afferent pupillary defects may not be a useful test to differentiate amblyopic eyes from healthy corresponding eyes.