Myopic Anisometropia Research Articles

Study on the impact of refractive anisometropia on strabismus, stereopsis, and amblyopia in children.

To preliminarily explore the correlation between different types and degrees of refractive errors and strabismus, amblyopia, and stereopsis. A retrospective collection was conducted on a total of 145 patients with anisometropia who visited our hospital for strabismus and pediatric ophthalmology from January 2023 to August 2023.Based on the nature of anisometropia in both eyes, it was divided into 4 groups: Farsighted anisometropia (36 cases); myopic anisometropia (38 cases); astigmatic anisometropia (35 cases); mixed anisometropia (36 cases), and 30 children with normal vision were collected. Both groups of subjects underwent routine slit lamp and fundus examinations to exclude other organic eye diseases. The test indexes were: visual acuity, diopter, strabismus, far-stereoscopic vision, near-stereoscopic Titmus, and random static zero-order stereoscopic vision. The results of this study showed that compared with the normal control group, the incidence of strabismus was higher in the anisometropia group. When the refractive error was ≥1.00D, the far stereopsis and random dot static 0-order stereopsis in the anisometropia group decreased more significantly, and the difference between the groups was statistically significant (P < .05). Far-sighted and mixed astigmatism were more prone to amblyopia than myopia and regular astigmatism (P < .05). However, there was no statistical difference in near stereopsis Titmus between the anisometropia group and the control group (P > .05). Children with anisometropia are more likely to have strabismus, stereopsis and amblyopia than normal children.

Effects of orthokeratology and spectacle lenses with highly aspherical lenslets on unilateral myopic anisometropia control.

To evaluate the 1-year effects of orthokeratology (OK) lenses and spectacle lenses with highly aspherical lenslets (HALs) on axial length (AL) elongation in children with unilateral myopic anisometropia. This ambispective cohort study recruited 81 children aged 8-14 years with unilateral myopic anisometropia. Of these, 42 participants (mean age 11.07 ± 1.54 years; 23 males) were treated with monocular OK lenses (OK group), and 39 (mean age 10.64 ± 1.72 years; 22 males) with binocular HALs (HAL group). Changes in AL and spherical equivalent refraction (SER) from baseline at 3, 6 and 12 months were compared between eyes and groups. Kaplan-Meier estimation and Cox proportional hazard regression were performed to analyse the risk of myopia onset in the initially non-myopic eyes. Mean axial elongation in the myopic and non-myopic eyes at the 12-month follow-up visit were 0.17 ± 0.20 and 0.41 ± 0.26 mm in the OK group (p < 0.001) and 0.10 ± 0.15 and 0.12 ± 0.12 mm in the HAL group (p = 0.32), respectively. Compared with the OK group, the non-myopic eyes in the HAL group had less axial elongation, lower cumulative myopia incidence and percentage of participants with rapid myopic shift at the 6- and 12 month follow-up (all p < 0.05). Cox regression analysis showed that a higher initial SER decreased the risk of myopia onset significantly in the initially non-myopic eyes (B = -2.06; 95% CI, 0.03-0.49; p = 0.003). Monocular OK lenses suppressed axial elongation in the myopic eye and minimised anisometropia; however, the non-treated contralateral eye may experience faster myopia onset and myopic shift. Binocular HALs can effectively reduce axial elongation in both eyes of children with unilateral myopic anisometropia.

Spectacle correction may affect refractive progression in children with unilateral myopic anisometropia: A retrospective study.

To investigate the effect of spectacle correction on refractive progression in children with unilateral myopic anisometropia (UMA). In this retrospective study, 153 children with UMA (aged 8-12 years) were recruited and classified into an uncorrected (UC) group (n = 47) and a spectacle (SP) group (n = 106). The spherical equivalent refraction (SER) of the myopic eyes ranged from -0.75 to -4.00 D; the SER of the emmetropic eyes ranged from +1.00 to -0.25 D; anisometropia was ≥1.00 D and the follow-up duration was 1 year. Nineteen subjects from the SP group with follow-up records spanning at least 6 months before and after wearing spectacles were selected as a subgroup. Changes in the SER and axial length (AL), the degree of anisometropia and interocular AL differences of the two groups and the subgroup were analysed. During the 1-year follow-up period, AL and SER changes in myopic eyes were significantly greater than those in emmetropic eyes in the UC group (p < 0.001). For the UC group, the degree of anisometropia and AL change increased (all p < 0.001). For the SP group, there were no significant differences in the degree of anisometropia or AL change (all p > 0.05). When comparing the groups, AL elongation of the myopic eyes in the UC group occurred significantly faster than in the SP group (p = 0.02), and AL elongation for the emmetropic eyes in the UC group occurred significantly slower than in the SP group (p = 0.04). For the subgroup, the AL and SER changes in the myopic eyes 6 months before wearing spectacles occurred significantly faster than those after correction (p < 0.001). Spectacle correction could prevent increased anisometropia in uncorrected children with UMA by slowing myopia progression in the myopic eyes and accelerating the myopic shift in the contralateral eye.

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

BackgroundConsidering 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.MethodsSubjective 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.ResultsThe 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).ConclusionsIn 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.

Comment on: Observation of peripheral refraction in myopic anisometropia in young adults

Comment on: Observation of peripheral refraction in myopic anisometropia in young adults

Characteristics of peripheral refractive errors in eyes of patients with non-amblyopic myopic anisometropia

BackgroundThis study aims to investigate relative peripheral refractive (RPR) characteristics in children with non-amblyopic myopic anisometropia and explore potential associations between relative peripheral refractive errors (RPRE) and myopia.MethodsRelative peripheral refractive errors were assessed in 64 children diagnosed with non-amblyopic myopic anisometropia utilizing multispectral refraction topography (MRT). Two eyes of each patient were divided into into the more myopia eyes group (ME) and the fellow eyes group (FE). Evaluated parameters encompassed total defocus values (TRDV), defocus values at eccentricities spanning 0 to 15 degrees (RDV-15), 0 to 30 degrees (RDV-30), 0 to 45 degrees (RDV-45), as well as superior (RDV-S), inferior (RDV-I), temporal (RDV-T), and nasal (RDV-N) positions.ResultsThe study revealed a noteworthy contrast in TRDV values between Group ME (0.52 ± 0.36) and Group FE (0.17 ± 0.41), with a substantial significance (P < 0.0001). While no significant RDV-15 difference emerged between Group ME (0.01 ± 0.05) and Group FE (-0.01 ± 0.07) (P > 0.05), a meaningful RDV-30 difference existed between Group ME (0.11 ± 0.14) and Group FE (0.03 ± 0.19) (P = 0.0017). A significant discrepancy in RDV-45 was also observed between Group ME (0.39 ± 0.29) and Group FE (0.13 ± 0.34) (P < 0.001). Notably, RDV-I and RDV-T positions demonstrated marked differences between Group ME and Group FE (P < 0.0001), whereas no significant disparity was noted in RDV-S and RDV-N positions (P > 0.05).ConclusionEyes exhibiting greater myopia manifested more hyperopic peripheral defocus in the context of anisometropia. MRT as a novel ophthalmic evaluation technique, holds promising potential for broader clinical applications in the future.

Choriocapillaris flow features in children with myopic anisometropia

AimsTo examine differences between the eyes in choriocapillaris perfusion and choroidal thickness in children with myopic anisometropia.MethodsIn this observational and prospective study, 46 children with myopic anisometropia were enrolled. Choriocapillaris...

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

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). 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. 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. 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.

Accommodation and Binocular Vision in Children with Myopic Anisometropia.

To assess the differences in accommodation and binocular vision in children with myopic anisometropia and determine the correlation with anisometropia. A total of 110 patients with myopia aged 8-15 years were recruited from June 2021 to February 2022 from the Affiliated Hospital of Xuzhou Medical University. Based on the interocular differences of spherical equivalent refraction, patients were divided into the isometropia (35 children), low anisometropia (LA group, 42 children), and high anisometropia (HA group, 33 children). The variables assessed were refraction, heterophoria, amplitude of accommodation (AMP), accommodative response (AR), gradient AC/A, positive and negative relative accommodation (PRA/NRA), and near stereopsis in the three groups. Pearson's correlation coefficient tests were used to investigate the possible association between each parameter and interocular differences (IODs). Among 110 subjects, there were 49 males and 61 females with a mean age of 11.39 ± 2.28 years. Compared with those in the isometropia group, AMP was lower and near stereopsis was higher in the LA group, and the distance and near heterophoria, PRA, AR, and near stereopsis were higher, and PRA, AMP, and gradient AC/A were lower in the HA group (all P < 0.05). Compared with those in the LA group, the near stereopsis, AR, and the near stereopsis were higher in the HA group, and the gradient AC/A was lower (all P < 0.05). However, no significant differences existed in the negative relative accommodation (P > 0.05). The distance and near heterophoria, AR, AMP, and near stereopsis were observed to be correlated with IODs, respectively (r = -0.259, p = 0.006; r = -0.201, p = 0.036; r = 0.306, p = 0.001; r = -0.315, p = 0.001; r = 0.535, p < 0.001). Our results suggested that with the increase of anisometropia, distance and near heterophoria, AR, AMP, and near stereopsis had a tendency to get worse in children with myopic anisometropia.

Prevalence of anisometropia and its associated factors in school-age children

ABSTRACT Purpose To determine the prevalence of anisometropia and the associated demographic and biometric risk factors in children. Methods This cross-sectional study was conducted on the elementary school children of Shahroud, east of Iran, in 2015. All rural students were recruited, while multistage cluster sampling was used to select the students in urban areas. All children underwent optometric examinations including the measurement of uncorrected and corrected visual acuity, autorefraction, and subjective refraction with cycloplegia. Biometric components were measured using the Allegro Biograph. Myopia and hyperopia were defined as a spherical equivalent ≤−0.5 and ≥ +2.00 diopter, respectively. Students with a history of ocular trauma or lack of cycloplegic refraction at least in one eye were excluded from the study. Results Of 6624 selected children, 5620 participated in the study. After applying the exclusion criteria, the data of 5357 students (boys: 52.8%, n = 2834) were analyzed. The mean age of the subjects was 9.2 ± 1.7 years (range: 6–12 years). The prevalence of anisometropia ≥ 1 D was 1.1% (95% CI: 0.8 to 1.4) in all children, 1.0% (95% CI: 0.7–1.3) in boys, 1.3% (95% CI: 0.8–1.7) in girls, 1.1% (95% CI: 0.8–1.4) in urban children, and 1.4% (95% CI: 0.5–2.3) in rural children. The prevalence of anisometropia was 8.8% (95% CI: 5.3–12.2) in myopic and 5.7% (95% CI: 2.8–8.5) in hyperopic children. Axial length asymmetry (OR = 40.9; 95%CI: 10.2–164.1), myopia (OR = 17.9; 95% CI: 9.4–33.9), and hyperopia (OR = 10.1; 95% CI: (5.1–19.7) were associated with anisometropia in multiple logistic regression model. More anisometropia was associated with more severe amblyopia. The odds of amblyopia (OR = 82.3: 38.2-177-3) and strabismus (OR = 17.6: 5.5–56.4) were significantly higher in anisometropic children. The prevalence of amblyopia was 21.7% in children with myopic anisometropia ≥ 3D, 66.7% in children with hyperopic anisometropia ≥ 3D, and 100% in cases with antimetropia ≥ 3D. Conclusion The prevalence of anisometropia was low in Iranian school children. However, a high percentage of anisometropic students had amblyopia and strabismus. Axial length was the most important biometric component associated with anisometropia.

Myopic anisometropia associated with exotropia and hypotropia: case report and literature review

Myopic anisometropia associated with exotropia and hypotropia: case report and literature review

Comparative analysis of corneal parameters in simple myopic anisometropia using Scheimpflug technology.

This study aims to investigate the differences in binocular corneal parameters and their interrelation with binocular biometric parameters asymmetry in patients with simple myopic anisometropia, thereby elucidating the influence of myopia process on various corneal parameters. In this cross-sectional study, 65 patients with anisometropia in monocular myopia were included. They were divided into low anisometropia group: 3.00D<Δ spherical equivalent (SE)≤-1.00D (Δ represents the difference between the two eyes, i.e., myopic data minus emmetropic data) and high anisometropia group: ΔSE ≤ -3.00D. Corneal and ocular biometric parameters were measured using Pentacam, Corvis ST, and IOL Master 700. Statistical analyses focused on the binocular corneal parameters asymmetry, using the contralateral emmetropia as a control. The mean age of participants was 18.5 ± 1.3 years, with the average SE for myopia and emmetropia being -2.93 ± 1.09D and -0.16 ± 0.41D, respectively. The central corneal thickness (CCT), flat keratometry (Kf), keratometry astigmatism (Ka), total corneal aberration (6mm) (TOA), surface variance index (ISV), vertical asymmetry index (IVA), stress-strain index (SSI), and first applanation stiffness parameter (SPA1) and ambrosia relational thickness-horizontal (ARTh) showed significant differences between anisometropic fellow eyes (p < 0.05). There were significant differences in ΔIVA, Δ the difference between the mean refractive power of the inferior and superior corneas (I-S), Δ deviation value of Belin/Ambrósio enhanced ectasia display (BAD-D), Δ deformation amplitude ratio max (2mm) (DAR)and Δ tomographic biomechanical index (TBI) (p < 0.05) in two groups. Asymmetry of corneal parameters was correlated with asymmetry of ocular biometric parameters. Anisometropia (ΔSE) was positively correlated with ΔIVA (r = 0.255, p = 0.040), ΔBAD-D (r = 0.360, p = 0.006), and ΔSSI (r = 0.276, p = 0.039) and negatively correlated with ΔDAR (r = -0.329, p = 0.013) in multiple regression analysis. Δ mean keratometry (Km), Δ anterior chamber depth (ACD), and Δ biomechanically corrected intraocular pressure (bIOP) were also associated with binocular corneal differences. Compared to contralateral emmetropia, myopic eyes have thinner corneas and smaller corneal astigmatism. Myopic corneas exhibit relatively more regular surface morphology but are more susceptible to deformation and possess marginally inferior biomechanical properties. In addition, there is a certain correlation between anisometropia and corneal parameter asymmetry, which would be instrumental in predicting the development of myopia.

Observation of peripheral refraction in myopic anisometropia in young adults.

To investigate the differences in retinal refraction difference values (RDVs) of adult patients with myopic anisometropia compared with those without myopic anisometropia, and to investigate the relationship between ocular biometric measurements and relative peripheral refraction. This clinical observation study included 130 patients with myopia (-0.25 to -10.00 D) between October 2022 and January 2023 aged between 18 and 40y. The patients were divided into anisometropia (n=63; difference in binocular anisometropia ≥1.00 D) and non-anisometropia (n=67; difference in binocular anisometropia <1.00 D) groups accordingly. Ocular biometric measurements were performed by optical biometrics and corneal topography to assess the steep keratometry (Ks), flap keratometry (Kf), axial length (AL), corneal astigmatism (CYL; Ks-Kf), surface regularity index (SRI), surface asymmetry index (SAI), and central corneal thickness (CCT). The RDV was measured at five retinal areas from the fovea to 53 degrees (RDV-0-10, RDV-10-20, RDV-20-30, RDV-30-40, and RDV-40-53), the total RDV (TRDV) of 53 degrees, and four regions, including RDV-superior, RDV-inferior, RDV-temporal, and RDV-nasal. An analysis of Spearman correlation was carried out to examine the correlation between RDV and the spherical equivalent (SE) and ocular biological parameters. Within RDV-20-53, both groups showed relative hyperopic defocus, and the increase in RDV corresponds to the increase in eccentricity. In the myopic anisometropia group, the TRDV, RDV-20-53, RDV-superior, and more myopic eyes had significantly higher RDV-temporal values than less myopic eyes. (P<0.05). In the non-anisometropia group, there was no significant difference in the RDV between the more and less myopic eyes at different eccentricities (P>0.05). There was a negative correlation between SE and TRDV (r=-0.205, P=0.001), RDV-20-53 (r=-0.281, -0.183, -0.176, P<0.05), RDV-superior (r=-0.251, P<0.001), and RDV-temporal (r=-0.230, P<0.001), a negative correlation between CYL and RDV-10-30 (r=-0.147, -0.180, P<0.05), and a negative correlation between SRI and RDV-0-20 (r=-0.190, -0.170, P<0.05). AL had a positive correlation with RDV-20-30 (r=0.164, P=0.008) and RDV-temporal (r=0.160, P=0.010). More myopic eyes in patients with myopic anisometropia show more peripheral hyperopic defocus. Diopter and corneal morphology may affect peripheral retinal defocus.

Effectiveness and the nomogram of small incision lenticule extraction in the correction of myopic anisometropia in adults.

To evaluate the safety, effectiveness, and predictability of small incision lenticule extraction (SMILE) for the treatment of anisometropia, and to explore the personalized design scheme of SMILE in correcting adult myopia anisometropia based on the nomogram. It's a prospective cohort study. Patients with anisometropic myopia of refractive difference ≥ 2.0 diopters (D) who underwent SMILE between September 2020 and March 2021 were enrolled. Clinical features and visual function were assessed preoperatively and at 1wk, 1, 3, and 6mo after the operation. The examination included tests for uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refractive errors, effectiveness index (preoperative CDVA/postoperative UDVA), safety index (postoperative CDVA/preoperative CDVA), nomogram and stereoscopic function. Paired t-test, Wilcoxon signed-rank test and repeated-measures analyses of variance were used for continuous variables, and Pearson Chi-squared test was used for categorical variables. The study involved 45 consecutive patients (average age: 25.0±6.9y; 82 out of 90 eyes underwent SMILE, while 8 eyes were not operated). The average preoperative spherical equivalent (SE) was -4.74±0.22 D. Six months after surgery, the effectiveness index was 1.05±0.12, and the safety index was 1.09±0.11. Seventy eyes (85.4%) exhibited SE correction error within ±0.5 D. The percentage of eyes with Titmus stereoscopic function equal to or less than 200″ significantly increased from 55.6% preoperatively to 88.9% postoperatively (P<0.05). There was statistically significant difference between higher myopia eyes and contralateral eyes in average nomogram value/spherical refraction ratio. SMILE is safe, effective and predictable in correcting myopic anisometropia, and it improves stereoscopic visual function of anisometropia patients. The precise and individualized design of the nomogram is a vital element to ensure the balance of both eyes after SMILE.

Relative corneal refractive power shift and inter-eye differential axial growth in children with myopic anisometropia treated with bilateral orthokeratology

PurposeTo investigate the relationship between relative corneal refractive power shift (RCRPS) and axial length growth (ALG) in bilateral myopic anisometropes treated with orthokeratology.MethodsA total of 102 children with myopic anisometropia in this prospective interventional study were randomly assigned to the spectacle group and orthokeratology group. Axial length (AL) and corneal topography was measured at baseline and the 12-month follow-up visit. ALG was defined as the difference between the two measurements, and RCRPS profiles were calculated from two axial maps obtained.ResultsIn the orthokeratology group, the ALG in the more myopic eye (0.06 ± 0.15 mm) was significantly smaller than that in the less myopic eye (0.15 ± 0.15 mm, p < 0.001), and the interocular difference in AL significantly decreased following 1-year treatment, from 0.47 ± 0.32 to 0.38 ± 0.28 mm (p < 0.001). However, in the spectacle group, the ALG was similar between the two eyes, and the interocular difference in AL did not change significantly over one year (all p > 0.05). The interocular difference in ALG in the orthokeratology group was significantly correlated with the interocular difference in RCRPS (dRCRPS, β=−0.003, p < 0.001) and the interocular difference in baseline AL (β=−0.1179, p < 0.001), with R2 being 0.6197.ConclusionOrthokeratology was effective in decreasing the magnitude of anisometropia. The interocular variation in RCRPS is an important factor accounting for the reduction of interocular ALG difference in anisomyopic children post-orthokeratology. These results provide insight into establishing eye-specific myopia control guidelines during orthokeratology treatment for myopic anisometropes.

Changes in axial length in anisometropic children wearing orthokeratology lenses.

There is a particular anisometropia occurring in one eye with myopia, while the other eye has very low myopia, emmetropia, or very low hyperopia. It is unclear how the binocular axial length changes when these children wear unilateral OK lenses only in the more myopic eyes. This study investigates the changes in the axial elongation of both eyes. This is a 1-year retrospective study. In total, 148 children with myopic anisometropia were included. The more myopic eyes were wearing orthokeratology lenses (treated eyes), whereas the contralateral eyes were not indicated for visual correction (untreated eyes). The untreated eyes were classified into three subgroups based on the spherical equivalent refraction (SER): low myopia (≤ -0.50 D, n = 37), emmetropia (+0.49 to -0.49 D, n = 76), and low hyperopia (≥0.50 D, n = 35). Changes in the axial length (AL) were compared between the untreated and treated eyes and among the three subgroups. The axial elongation was 0.14 ± 0.18 mm and 0.39 ± 0.27 mm in all treated and untreated eyes, respectively (p < 0.001). The interocular AL difference decreased significantly from 1.09 ± 0.45 mm at the baseline to 0.84 ± 0.52 mm at 1 year (p < 0.001). The baseline median (Q1, Q3) SER of the untreated eyes were -0.75 D (-0.56, -0.88 D), 0.00 D (0.00, -0.25 D), and +0.75 D (+1.00, +0.62 D) in low myopia, emmetropia, and low hyperopia subgroups, respectively. The axial elongation was 0.14 ± 0.18 mm, 0.15 ± 0.17 mm, and 0.13 ± 0.21 mm (p = 0.92) in the treated eyes and 0.44 ± 0.25 mm, 0.35 ± 0.24 mm, and 0.41 ± 0.33 mm in the untreated eyes (p = 0.11) after 1 year. Multivariate linear regression analyses only showed significant differences in axial elongation between the emmetropia and low myopia subgroups of untreated eyes (p = 0.04; p > 0.05 between other subgroups). Unilateral orthokeratology lenses effectively reduced axial elongation in the more myopic eyes and reduced interocular AL differences in children with myopic anisometropia. The refractive state of the untreated eyes did not affect the axial elongation of the more myopic eye wearing the orthokeratology lens. In the untreated eyes, AL increased faster in the low myopia subgroup than in the emmetropia subgroup.

Characteristics of the Peripapillary Structure and Vasculature in Patients With Myopic Anisometropia.

To evaluate the interocular differences of the peripapillary structural and vascular parameters and that of association with axial length (AL) in participants with myopic anisometropia using swept-source optical coherence tomography. This prospective cross-sectional study included 90 eyes of 45 participants. Each participant's eyes were divided into the more and less myopic eye respectively according to spherical equivalent. The β- and γ-parapapillary atrophy (PPA) areas, Bruch's membrane opening distance, border length, and border tissue angle were measured manually. Peripapillary choroidal vascularity index and choroidal thickness (CT) values in superior, nasal, inferior, and temporal were calculated using a custom-built algorithm based on MATLAB. The interocular difference in AL and spherical equivalent was 0.62 ± 0.26 mm and -1.50 (-2.13, -1.25) diopters (D), respectively. The interocular difference in spherical equivalent was highly correlated with that of the AL. The β- and γ-PPA areas were significantly greater in more myopic eyes. The mean and inferior peripapillary choroidal vascularity index and all regions of peripapillary CT were significantly lower in the more myopic eyes. The interocular difference in AL was significantly positively correlated with the interocular differences in γ-PPA area and border length and negatively correlated with the interocular differences in temporal choroidal vascularity index and mean, inferior, and temporal peripapillary CT. There was an independent correlation between the interocular differences in AL and the interocular differences in γ-PPA area, inferior, and temporal peripapillary CT. Significant differences between both groups were detected in most peripapillary parameters, especially in peripapillary CT. The γ-PPA area, border length, and peripapillary CT were significantly correlated with the elongation of AL. The current study characterized and analyzed the peripapillary parameters in myopic anisometropia, which helped to monitor myopic progression.

Anatomical and optical parameters and aberrations of the optical system of the eye in anisometropic myopia

Purpose: to compare anatomical and optical parameters and aberrations of both eyes in patients with acquired and congenital anisometropic myopia.Material and methods. 22 patients (44 eyes) aged 18–35 (averagely, 25.2) with acquired and congenital anisometropic myopia were examined using the Galilei G6 optical eye system analyzer (Ziemer, Switzerland). The analysis of total, corneal and internal aberrations of the eye was carried out on an OPD-Scan III (Nidek) aberrometer.Results. In both groups with acquired and congenital anisometropic myopia, the axial length of the higher myopic eye was greater than that of the fellow eye. A greater asphericity and higher astigmatism of the cornea were revealed in higher myopic eyes of patients with congenital myopia as compared to acquired myopia. The total RMS HOA in congenital myopia was significantly greater in the higher myopic eye compared to the fellow eye (1.07 D and 0.68 D, respectively) and greater than in cases of acquired myopia. All HOA were greater in higher myopic eyes as compared to the fellow ones in cases of congenital myopia. In case of acquired myopia only the total coma appeared to be greater in the higher myopic eye. Corneal aberrations in acquired anisometropic myopia did not differ in the paired eyes. In case of congenital myopia, the total tilt was significantly greater in the higher myopic eye, and total coma and spherical aberration have lower values, even with a transition to negative ones (p &lt; 0.05).Conclusion. The revealed differences of the wavefront of the eyes with anisometropic congenital and acquired myopia are rather a consequence of anatomical and optical differences (the axial length of the eyes and the topography of the cornea), than the cause of anisometropia.

Presumed Unindicated Implantation of Posterior Chamber Phakic Intraocular Lens.

BACKGROUND Refractive surgery is one of the most frequently performed ocular surgeries worldwide. Implantation of the posterior chamber phakic intraocular lens has advantages over laser vision correction, especially in high refractive error cases. We present a case of a young adult women with poor vision who underwent bilateral posterior chamber phakic intraocular lens explantation due to high vault, shallow anterior chambers, and a picture of cone-rod dystrophy. CASE REPORT A 23-year-old woman was referred for poor vision following an implantation of bilateral toric implantable collamer lens (ICL) implantation when she was 18 years old for high myopic astigmatism and anisometropia. On presentation, the best corrected visual acuity was 4-6/200 and 2-3/200 in the right eye and left eye, respectively. Slit lamp examination indicated a clear cornea with pigment deposition on the endothelium, high ICL vault, shallow anterior chamber, and bowing of the iris bilaterally. The patient underwent bilateral removal of the ICLs on separate visits, yet the vision remained unchanged. Diagnostics revealed that the patient had bull's eye maculopathy with atrophy due to her cone-rod dystrophy, which caused the poor vision. CONCLUSIONS This report emphasizes the need for careful and appropriate patient and intraocular size selection for refractive surgery. It indicates the importance of thorough medical examination, including genetic testing, fundus examination, and optical coherence tomography when retinal dystrophy is suspected. Generally, close follow-up is crucial in the setting of high vaulting following ICL implantation to prevent secondary complications.

Assessment of the effects of induced anisometropia on binocularity with glasses-free 3D technique.

To assess the effect of experimentally induced anisometropia on binocularity in normal adults with glasses-free three-dimensional (3D) technique. Totally 54 healthy medical students with normal binocularity in the cross-sectional study were enrolled. Anisometropia was induced by placing trail lenses over the right eye, in 0.5 D steps including lenses of -0.5, -1, -1.5, -2, -2.5 D (hyperopic anisometropia) and lenses of +0.5, +1, +1.5, +2, +2.5 D (myopic anisometropia). The glasses-free 3D technique was used to evaluated not only fine stereopsis, but also coarse stereopsis, dynamic stereopsis, foveal suppression, and peripheral suppression in these subjects. One-way analysis of variance was used to compare quantitative data such as fine stereopsis, coarse stereopsis. Pearson's Chi-square test was performed to compare categorical data such as dynamic stereopsis, foveal suppression and peripheral suppression. The subjects showed a statistically significant decline in fine stereopsis, coarse stereopsis, and dynamic stereopsis with increasing levels of anisometropia (P<0.001). Binocularity was affected when induced anisometropia was more than 1 D (P<0.05). Foveal suppression and peripheral suppression were evident and increased in proportion to anisometropia (P<0.001). The relatively low degrees of anisometropia may have a potentially significant effect on high-grade binocular interaction. The mechanisms underlying the defect of binocularity seem to involve not only foveal suppression, but also peripheral suppression.