Myopia Group Research Articles

Comparison of corneal and lens density measurements obtained by Pentacam and CASIA2 in myopes

PurposeTo investigate the agreement between Pentacam and CASIA2 in the evaluation of corneal densities (CDs) and lens densities (LDs) in myopes.MethodsFifty-three patients (106 eyes) underwent comprehensive ophthalmologic examinations. CDs and LDs were measured using Pentacam and CASIA2, respectively, based on the grayscale percentage of the obtained images. Agreement between Pentacam and CASIA2 was evaluated using the consistency intraclass correlation coefficient (ICC) and represented using Bland-Altman plots.ResultsCompared to Pentacam, CASIA2 showed significantly higher CD and LD values in all measured zones. The ICC of the average CD and LD measured by the Pentacam and CASIA2 were 0.726 and 0.757, respectively. The ICC values of all corneal zones and lenses were above 0.7, except for the measurement of the cornea in the 0–2 mm zone (0.455), suggesting good consistency between the two devices, whose results were of different levels of linear correlation. Bland-Altman plots showed mean percentages of 3.93% for the points falling outside the limits of agreement among the densitometry results. The ICCs in different age groups were similar, but the agreement was poorer in the high myopia group (low and moderate myopia, CD: 0.739, LD: 0.753; high myopia, CD: 0.621, LD: 0.760).ConclusionsCASIA2 demonstrated good consistency with Pentacam in the measurement of CD and LD, except for measurement of CD in the central cornea and in high myopia. Despite difference in the numerical results compared with Pentacam, which made the two devices uninterchangeable, CASIA2 provides a reliable alternative densitometric measurement method.

Turkish children myopia progression in the urban area, a retrospective evaluation

Aims: To investigate myopia trends and progression in urban school-aged myopic children in Turkey.
 Methods: This retrospective study included myopic children aged 6-18 years attending the ophthalmology clinic for regular eye and refractive examinations between 2003 and 2021. Myopia progression was calculated as the difference between the baseline and the last visit spherical equivalent refractive (SER) values. Individuals were further categorized to determine the age-specific myopia progression as 6-11, 12-16, and 17-18 age groups based on the school periods of the country. According to the SER values, individuals were classified into mild, moderate, and high myopic groups. 
 Results: A total of 602 eyes of 301 children (191 female, 110 male) with a mean age of 11.64±2.81 (6-18) years were included in the study. The mean follow-up time of patients was 37.51±19.18 (6-98) months. The baseline mean SER value was -1.5±1.07 D (range: -0.50 and -5.62) and -2.55±1.50 at the final visit. The overall mean myopia progression was -0.35±0.37 D (range: +0.35 D and -3.75 D/year. There were 46 children between 6-11 years, 173 children between 12-16 years, 82 children between 17-18 years, and the annual SER changes were -0.46±0.40 D; -0.37±0.39 D and -0.26±0.29 D in the groups, respectively (p < 0.001). Baseline, final, and annual myopia progression were greater in females. Although there was no statistical significance, myopia progression was faster in moderate myopes (-0.39±0.33 D/a year), followed by mild (-0.35±0.37 D/a year) and high myopes (-0.21±0.20 D/a year) (p=0.37).
 Conclusion: The progression of myopia in school-aged Turkish children from the Western Black Sea Region is comparable to the world. Our study revealed the greater myopia progression in the youngest children, moderate myopia group, and females. Myopia prevention recommendations should be carefully advised to the youngest female ones to reduce myopia progression.

Reduction of experimental ocular axial elongation by neuregulin-1 antibody.

Since the mechanisms underlying myopic axial elongation have remained unclear, we examined the effect of neuregulin-1 (NRG-1), an epidermal growth factor family member, on myopic axial elongation. The guinea pigs aged two to three weeks were subjected to bilateral negative lens-induced axial elongation and received weekly intravitreal injections into their right eyes of NRG-1 antibody (doses: 5 μg, n = 8; 10 μg, n = 8, 20 μg, n = 9) or of NRG-1 (doses: 0.05 μg, n = 8; 0.01 μg, n = 9; 0.2 μg, n = 8), underwent only bilateral negative lens-induced axial elongation (myopia control group, n = 10), or underwent no intervention (control group, n = 10). The contralateral eyes received corresponding intravitreal phosphate-buffered solution injections. One week after the last injection, the guinea pigs were sacrificed, the eyeballs were removed, the thicknesses of the retina and sclera were histologically examined, the expression of NRG-1 and downstream signal transduction pathway members (ERK1/2 and PI3K/AKT) and the mRNA expression of NRG-1 in the retina was assessed. The inter-eye difference in axial length at study end increased (p < 0.001) from the normal control group (-0.02 ± 0.09 mm) and the myopia control group (-0.01 ± 0.09 mm) to the low-dose NRG-1 antibody group (-0.11 ± 0.05 mm), medium-dose NRG-1 antibody group (-0.17 ± 0.07 mm), and high-dose NRG-1 antibody group (-0.28 ± 0.06 mm). The relative expression of NRG-1, ERK1/2, and PI3K/AKT in the retina decreased in a dose-dependent manner from the myopia control group to the NRG-1 antibody groups and the normal control group. The relative NRG-1 mRNA expression in the retina was higher (p < 0.01) in the myopic control group than in the NRG-1 antibody groups and normal control group. Scleral and retinal thickness decreased from the normal control group to the NRG-1 antibody groups to the myopic control group. After intraocular injection of NRG-1 protein, there was a slight dose-dependent increase in the difference in axial length between the right and left eye, however not statistically significantly, from the normal control group (-0.02 ± 0.09 mm) to the high-dose NRG-1 protein group (0.03 ± 0.03 mm; p = 0.12). Intravitreal NRG-1 antibody application was dose-dependently and time-dependently associated with a reduction in negative lens-induced axial elongation in young guinea pigs.

Corneal metabolic biomarkers for moderate and high myopia in human

This study aimed to identify the corneal metabolic biomarkers for moderate and high myopia in human. We enrolled 221 eyes from 221 subjects with myopia to perform the femtosecond laser small incision lenticule extraction (SMILE) surgery. Among these, 71 eyes of 71 subjects were enrolled in the low myopic group, 75 eyes of 75 subjects in the moderate myopic group and 75 eyes of 75 subjects in the high myopic group. The untargeted metabolomics analysis was performed to analyze the corneal tissues extracted during the SMILE surgery using an ultra-high-performance liquid chromatography (UHPLC) coupled to a quadrupole time-of-flight (Q-TOF) mass spectrometry (MS). The one-way analysis of variance (ANOVA) was used to identify the different metabolites among the three myopic groups, the orthogonal partial least-squares discriminant analysis (OPLS-DA) model was used to reveal the different metabolites between moderate myopia and low myopia, and between high myopia and low myopia. The Venn gram was used to find the overlapped metabolites of the three datasets of the different metabolites. The stepwise multiple linear regression analysis was used to determine the metabolic molecules associated with manifest refractive spherical equivalents (MRSE). The Receiver Operating Characteristics (ROC) analysis was performed to reveal the corneal biomarkers for moderate and high myopia. The hub biomarker was further selected by the networks among different metabolites created by the Cytoscape software. A total of 1594 metabolites were identified in myopic corneas. 321 metabolites were different among the three myopic groups, 106 metabolites were different between high myopic corneas and low myopic corneas, 104 metabolites were different between moderate myopic corneas and low myopic corneas, and 30 metabolic molecules overlapped among the three datasets. The multivariate linear regression analysis revealed the myopic degree was significantly influenced by the corneal levels of azelaic acid, arginine-proline (Arg-Pro), 1-stearoyl-2-myristoyl-sn-glycero-3-phosphocholine, and hypoxanthine. The ROC curve analysis showed that azelaic acid, Arg-Pro and hypoxanthine were effective in discriminating low myopia from moderate to high myopia with the area under the curve (AUC) values as 0.982, 0.991 and 0.982 for azelaic acid, Arg-Pro and hypoxanthine respectively. The network analysis suggested that Arg-Pro had the maximum connections among these three biomarkers. Thus, this study identified azelaic acid, Arg-Pro and hypoxanthine as corneal biomarkers to discriminate low myopia from moderate to high myopia, with Arg-Pro serving as the hub biomarker for moderate and high myopia.

Suppressive effect of nitric oxide synthase (NOS) inhibitor L-NMMA acetate on choroidal fibrosis in experimental myopic guinea pigs through the nitric oxide signaling pathway

Myopia is one of the most prevalent eye diseases that seriously threaten the eyesight of children and adolescents worldwide. However, the pathogenesis is still unclear, and effective drugs are still scarce. In the present study, the guinea pigs were randomly divided into a normal control (NC) group, a lens-induced myopia (LIM) group, a NOS inhibitor (L-NMMA) injection group, and a NOS inhibitor solvent phosphate-buffered saline (PBS) group and the animals received relevant treatments. After 2- and 4-week different treatments, we noted that the refraction and choroidal thickness in the LIM group decreased compared with the NC group, whereas the ocular axial length increased significantly, and the choroid showed a fibrotic trend. The expression of NOS1, NOS3, TGF-β1, COLI, and α-SMA at gene and protein levels was increased significantly in the choroid (all P < 0.05). After intravitreal injection of NOS inhibitor L-NMMA, we found that compared with the LIM group, the refraction and the choroidal thickness significantly increased, whereas the axial length reduced significantly, accompanied by an increase of choroidal thickness and an improvement of choroidal fibrosis. The expression levels of choroidal NOS1, NOS3, TGF-β, COLI, and α-SMA were significantly reduced (all P < 0.05). In conclusion, the trend of choroidal fibrosis in LIM guinea pigs is positively correlated with the increase in axial length. The NOS inhibitor L-NMMA can alleviate the process of choroidal fibrosis in myopic guinea pigs by inhibiting NO signaling pathway.

Fluid Supplementation Through Weakened Zonules via Side-Port Incision to Maintain Intraocular Pressure in High Myopic Eyes.

During phacoemulsification, the infusion pressure can cause the liquefied vitreous fluid to escape through the ciliary fiber interspace in highly myopic eyes, leading to reduced vitreous cavity pressure similar to vitrectomized eyes. This study assessed the probability of low intraocular pressure (IOP) in high myopic eyes with different axial length (AL) group undergoing cataract surgery, as well as the impact of balanced salt solution (BSS) supplementation and the optimal IOP value for such supplementation. The control group consisted of cataract eyes with normal AL (group 1: 22mm ≤ AL < 24.5mm), while cataract eyes with high axial myopia were categorized into three groups (group 2: 26mm ≤ AL < 28mm, group 3: 28mm ≤ AL < 30mm, group 4: AL ≥ 30mm). IOP was measured using the iCare pro tonometer intraoperatively. BSS supplementation was performed to raise IOP in cases of low IOP, before intraocular lens (IOL) implantation and before the end of surgery. The probability of low IOP was calculated, and the IOP before and after supplementation were compared. Ninety-five eyes were included. The total probability of low IOP in groups 2, 3, and 4 was 56.52, 62.50, and 70.83%, respectively, significantly higher than that in group 1 (16.67%). Similarly, the probability of low IOP before IOL implantation was significantly higher in groups 2, 3, 4 (43.48, 41.67, and 62.50%) compared to group 1 (4.17%, P < 0.05). The IOP before and after the first BSS supplementation in three high myopia groups were statistically significant (P < 0.05), increasing from 12.10mmHg (range, 6.0-24.9mmHg) to 16.60mmHg (range, 10.2-34.4mmHg). After the second BSS supplementation before the end of surgery, the IOP of high myopia groups increased from 12.60mmHg (range, 7.0-25.3mmHg) to 14.60mmHg (range, 9.8-25.3mmHg). The condition of highly myopic eyes seems more likely to develop low IOP during cataract surgery. There is an observed correlation: as AL increases, the total probability of low IOP rises. In patients with IOP < 9.5mmHg intraoperatively, fluid supplementation via a side-port incision can effectively raise IOP to about 16mmHg before IOL implantation and about 14mmHg after incision sealing, facilitating smoother IOL implantation and reducing the risk of postoperative low IOP. NCT, NCT05201677. Registered 23 November 2021-Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT05201677 .

Corneal remodeling after SMILE for moderate and high myopia: short-term assessment of spatial changes in corneal volume and thickness

PurposeTo evaluate the early corneal remodeling and its influencing factors after Small incision lenticule extraction (SMILE) for moderate and high myopia.MethodsThis was a retrospective study. Pre- and post-operative (1 week and 1, 3, 6 months) corneal volume (CV), mean keratometry (Km), and corneal thickness (CT) were measured by Scheimpflug tomography. CT at the central, thinnest point, and on concentric circles of 2, 4, and 6 mm diameter was recorded to assess corneal thickness spatial profile (CTSP) and percentage of thickness increase (PTI) in the moderate and high myopia groups, and to explore possible influencing factors.ResultsAfter SMILE, the peripheral CT decreased in the moderate myopia group and central corneal thickness (CCT) increased in the high myopia group at 1 month compared to 1 week (all P < 0.05). The CV, Km and CT were significantly increased at 3 months compared to 1 month (all P < 0.05), but there was no significant change at 6 months compared to 3 months for both groups (all P > 0.05). Patients with high myopia showed greater corneal thickness changes (△CT) and higher PTI than moderate myopia (all P < 0.05). Regression analysis revealed that in addition to refraction, peripheral PTI was negatively correlated with CCT in the moderate myopia group (4 mm: β = -0.023, P = 0.001; 6 mm: β = -0.050, P < 0.001), as well as in the high myopia group (4 mm: β = -0.038, P < 0.001; 6 mm: β = -0.094, P < 0.001). Moreover, peripheral PTI in the moderate myopia group was negatively correlated with age (4 mm: β = -0.071, P = 0.003; 6 mm: β = -0.162, P < 0.001).ConclusionsAfter SMILE, the CV, Km, and CTSP showed dynamic changes in the early stage, which stabilized after 3 months. Compared to the moderate myopia group, the high myopia group experienced slower corneal stabilization. The change in PTI at 6 months after SMILE may be related to higher preoperative refraction, thinner CCT and younger age.

Changes in relative peripheral refraction and optical quality in Chinese myopic patients after small incision lenticule extraction surgery.

To observe changes in retinal refraction difference values (RDV) and aberrations after small incision lenticule extraction (SMILE) surgery and evaluate their correlations. This study recruited 112 patients (112 eyes) who underwent SMILE for myopia. Participants were classified into the Low and Moderate Myopia group (LM, -0.50 to -6.0 D) and High Myopia group (HM, >-6.0 D) according to the central spherical equivalent (SE). RDVs in the five retinal eccentricities from 0° to 10°, 10° to 20°, 20° to 30°, 30° to 40°, and 40° to 53° are recorded as RDV-(0-10), RDV-(10-20), RDV-(20-30), RDV-(30-40), and RDV-(40-53), respectively; additionally, RDVs have four sectors, i.e., RDV-Superior (RDV-S), RDV-Inferior (RDV-I), RDV-Temporal (RDV-T), and RDV-Nasal (RDV-N). With a 3-month follow-up, changes in RDV (ΔRDV) and changes in aberrations [Δtrefoil, Δcoma, Δspherical aberration (SA), and Δtotal higher-order aberrations (HOA)] after surgery were recorded. No significant differences were observed in total RDV (TRDV), RDV-(0-53), RDV-S, RDV-I, RDV-N, trefoil, coma, and SA between the two groups before SMILE surgery. However, after SMILE, hyperopic defocus values [TRDV, RDV-(20-53), RDV-S, RDV-T, and RDV-N] in the LM group and hyperopic defocus values [TRDV, RDV-(20-53), RDV-S, and RDV-N] in the HM group were significantly lower at 3 months postoperatively than preoperatively, and the RDV-(40-53), RDV-S, and RDV-N were lower in the HM group than in the LM group. Aberrations [trefoil (vertical), coma, and HOA] in the LM group and aberrations (trefoil, coma, SA, and HOA) in the HM group were significantly higher at 3 months postoperatively than preoperatively, and the coma, trefoil(horizontal), SA, and HOA were higher in the HM group than in the LM group. In the multivariate analysis, ΔRDV-(40-53) was significantly correlated with ΔSA, and ΔRDV-T and ΔRDV-N were significantly correlated with Δcoma (horizontal). Our findings suggest that SMILE reduces retinal peripheral hyperopic defocus but introduces some higher-order aberrations, especially in people with high myopia refractive errors.

Accuracy of Seven Modern Online IOL Formulas in Eyes With Axial Lengths Longer Than 30 mm.

To evaluate the accuracy of newer online intraocular lens (IOL) formulas in extremely elongated eyes (axial length > 30 mm). This retrospective case series study included 236 patients (236 eyes). Postoperative refractive outcomes of the Barrett Universal II (BU II), Cooke K6 (K6), Emmetropia Verifying Optical (EVO) 2.0, Hoffer QST (HQST), Kane, Pearl-DGS, and Radial Basis Function (RBF) 3.0 formulas were compared. Subgroup analysis was performed in the extreme myopia group 1 (30 < axial length ≤ 32 mm), extreme myopia group 2 (32 < axial length ≤ 35 mm), and meniscus IOL group. The root mean square absolute prediction error (RMSAE) and proportions of eyes of prediction errors within ±0.50 diopters (D) were calculated for statistical analysis. For the extreme myopia group 1, RBF 3.0 achieved the lowest RMSAE (0.361) and EVO 2.0 showed the highest proportion of eyes within ±0.50 diopters (85.06%). For the extreme myopia group 2, the RMSAE of the K6 (0.442) and EVO 2.0 (0.475) was significantly lower than the BU II (0.610), Kane (0.641), and HQST (0.759, P ≤ .016) formulas. In the meniscus IOL group, the K6 formula showed the lowest RMSAE (0.402) and the highest percentage within ±0.50 diopters (84.31%). The EVO 2.0 and K6 formulas are recommended for IOL power calculation in eyes with extreme myopia. Modern artificial intelligence-based formulas should be used cautiously when the axial length is longer than 32 mm or meniscus IOLs are implanted. [J Refract Surg. 2023;39(10):705-710.].

Efficacy and Safety of Implantable Collamer Lens V4c Implantation in 1,834 Myopic Eyes for 1 Year of Follow-up.

To evaluate visual outcomes of patients with myopia after EVO Implantable Collamer Lens (ICL) (STAAR Surgical) implantation and predict risk factors of postoperative vault abnormalities. In this single-center, retrospective analysis, 1,834 eyes of 926 patients with myopia who underwent EVO ICL implantation were recruited between 2020 and 2021. Patients were followed up for 1 year, during which surgery outcomes were evaluated. In addition, 31 eyes with vault abnormalities who underwent secondary surgery were enrolled to form a generalized linear model, which aimed to predict risk factors contributing to vault abnormalities. At the final follow-up visit, safety and efficacy indexes were 1.12 ± 0.17 and 1.10 ± 0.19, respectively, and there was no statistical significance between the low and high myopia groups. Furthermore, 79.18% of eyes achieved a residual spherical equivalent within ±0.50 diopters. Except for the temporary elevation of intraocular pressure at 1 week postoperatively, IOP and endothelial cell density remained stable during follow-up visits. The rate of postoperative adverse events was 21.97% and most adverse events were transient. Vault abnormalities accounted for the majority of complications (9.54%). Results of generalized linear model showed that age was a risk factor for postoperative vault abnormalities, and the anterior chamber depth served as a protective factor (P < .05). Visual outcomes of EVO ICL implantation were satisfactory in safety and efficacy indexes in both the low and high myopia groups for 1 year of follow-up, with acceptable stability in postoperative spherical equivalent, intraocular pressure, and endothelial cell density. This study emphasized cautious ICL size selection for older patients and those with shallow anterior chamber depth. [J Refract Surg. 2023;39(10):694-704.].

Differences in Axial Length and Anterior Chamber Depth among Keratoconic, Myopic and Emmetropic Eyes

Purpose: To report variation of the axial length (AL) and anterior chamber depth (ACD) among keratoconic (KC) eyes compared to myopic and emmetropic eyes in an African population sample. Study Design: Cross sectional observational. Place and Duration of Study: Al-Faisal Eye Hospital at Khartoum state of Sudanfrom January 2022 to September 2022. Methods: One-hundred and twenty-four eyes of 62 patients were divided into KC group (n =17, eyes=34), myopic group (n=28, eyes=56), and an age/gender matched emmetropic group (n=17, eyes =34). Central corneal thickness (CCT) was measured using ultrasonic pachymeter, AL, ACD and keratometry readings (K-reading) were recorded for each patient using non-contact partial coherence interferometry with an IOL Master. Results: Mean age of the sample population was 22.27± 6.05 (range; 10 – 40 years). KC patients had the highest spherical equivalent of refraction (SER) (-6.19±3.91 dioptres), highest k-reading (48.98±5.68 dioptres) and the thinnest CCT. Myopic participants had a longer AL compared to other refractive error groups (AL=24.99±2.39, p&lt;0.001). KC patients exhibited a larger ACD in comparison to emmetropes and myopes (ACD=3.6?9±0.26, p&lt;0.001). Among all participants, SER exhibited the highest correlation with AL (r=-0.71, p&lt;0.001) followed by a weaker correlation with ACD (r=-0.26, p=0.003). However, among KC patients, SER exhibited a weaker correlation with AL compared to myopes (r=-0.55, p=0.001), and a higher correlation with ACD compared to myopes (r=-0.38, p=0.03). Conclusion: ACD and corneal curvature were the most significantly detrimental parameters in KC. KC participants demonstrated a lower correlation between SER and AL and higher correlation between SER and ACD.

Axial Length Control Is Associated With a Choroidal Thickness Increase in Myopic Adolescents After Orthokeratology.

To investigate the changes in choroidal thickness and axial length after orthokeratology in adolescents with low-to-moderate myopia and to explore the relationship between choroidal thickness and axial length variation. Thirty eyes with low-to-moderate myopia were retrospectively studied, and optometric data were collected before and after 6 months of continuous orthokeratology. Axial length and choroidal and foveal thicknesses were measured using optical biometry and enhanced depth imaging-spectral domain optical coherence tomography, respectively. Axial length in the low myopia group increased (P<0.001) after 6 months of orthokeratology, and the variation was greater than that in the moderate myopia group (P<0.05). The subfoveal choroidal thickness in low and moderate myopia groups increased (P<0.01), and the variation was greater in the moderate myopia group (P<0.05). Choroidal thickness in all seven measured spots increased, with the variation of subfovea, nasal 1 mm to fovea, and temporal 1 mm to fovea being statistically significant (P<0.001, P<0.05, and P<0.05). The change in axial length was negatively associated with subfoveal and average choroidal thicknesses (P<0.01). Adolescents with moderate myopia presented better axial length control after 6 months of orthokeratology. The choroidal thickness of low and moderate myopic eyes increased, and the variation was more significant in moderate myopic eyes. The axial length control effects can be associated with an increase in the subfoveal and average choroidal thickness.

Association between Central Corneal Thickness and Axial Length in Patients with Refractive Anomalies and Emmetropes

Background: This study aimed to determine the correlation between central corneal thickness (CCT) and axial length (AL) in patients with refractive anomalies and emmetropes. Methods and Results: The study included 330 respondents, with a total of 660 eyes, divided into two groups. The test group (TG) included 180 respondents with refractive anomalies (65 respondents with hypertropia, 65 with myopia, and 50 with astigmatism); the control group (CG) included 150 respondents with uncorrected visual acuity – 6/6 in both eyes. The CCT values were higher in the hypermetropic group compared to the myopic group (561.5±25.3 vs. 517.9±37.3 mm, P&lt;0.001), astigmatism group (561.5±25.3 vs. 528.3±35.3 mm, P&lt;0.001) and the CG (561.5±25.3 vs. 553.3±18.5 mm, P&lt;0.001). From 360 eyes in the TG with refractive anomalies, the lowest AL values were found in the hypermetropic group (21.7±1.0 mm) compared to the myopic group (P&lt;0.001), the astigmatism group (P&lt;0.001), and the CG (P&lt;0.001). Similar differences were also found for the right eyes (OD): hypermetrops tend to have shorter AL than the astigmatic group (P&lt;0.001), myopic group (P&lt;0.001), and the CG (emmetrope) (P&lt;0.001). Conclusion: The mean CCT value in the hyperopic group was higher than in the emmetropic group, while the CCT value of the myopic and astigmatic group was lower than that of the emmetropic group. AL values were the lowest in the hypermetropic group than in the myopic, astigmatic, and control groups.

Association Between Central Corneal Thickness and Intraocular Pressure in Patients with Refractive Anomalies and Emmetropes

Background: The aim of this study was to determine the relationship between central corneal thickness (CCT) and intraocular pressure (IOP) in patients with refractive anomalies and emmetropes. Methods and Results: This retrospective study was conducted in the Department of Ophthalmology at the University Clinical Center. The study included 330 respondents, with a total of 660 eyes, divided into two groups. The test group (TG) included 180 respondents with refractive anomalies (65 respondents with hypertropia, 65 with myopia, and 50 with astigmatism); the control group (CG) included 150 respondents with uncorrected visual acuity – 6/6 in both eyes. All respondents included in the research were aged 18–40, with an average age of 22.9 years. The values of CCT in TG was around 499.3–577.1 μm. From 360 eyes in the TG with refractive anomalies, the highest IOP values were found in the astigmatic group (20.6 mmHg) and the lowest values in the myopic group (15.3 mmHg) (P&lt;0.001) and were statistically higher compared to the CG (P&lt;0.001 in both cases). We found a statistically significant, moderate positive correlation between the values of CCT and IOP in the hypermetropic group (rs=0.655, 95% CI: 0.540 to 0.745, P&lt;0.0001) and a statistically significant low negative correlation (rs=-0.209, 95% CI: -0.373 to -0.033, P=0.0165) between the values of CCT and IOP in the myopic group. Also, a statistically significant low negative correlation (rs=-0.304, 95% CI: -0.510 to -0.152, P=0.0005) was found between the values of CCT and IOP in the astigmatism group. Conclusion: The results of our study show that increasing the CCT values in the hypermetropic group leads to an increase in the IOP values. Therefore, these findings can be used as a reference for our population, which would assist in the early diagnosis of ocular hypertension.

Genç Yetişkinlerde COVID-19 Pandemisi Dönemi Miyopi: Türkiye-Zonguldak İli Örneği

Aim: Investigating the relationship between the development and progression of myopia and digital&#x0D; screen time in young adults during the COVID-19 pandemic.&#x0D; Material and Methods: This single-centered, retrospective study included 106 young adults aged 18-&#x0D; 25 years, followed up in January-March 2019, 2020, and 2021. The patients were divided into two&#x0D; groups: emmetrope and myopia according to their baseline refractive values. The association between&#x0D; spherical equivalent refraction (SER) values and digital screen time before and during the pandemic&#x0D; was evaluated.&#x0D; Results: The mean age of 59 patients‘ (69.5% female) in the emmetrope group was 20.7±2.0, and&#x0D; 20.6±2.3 years of 47 patients (68.1% female) in the myopia group (p=0.422, p=0.877, respectively).&#x0D; The patients were reported to spend more time on digital devices in both groups (p

Effect of Myopia Severity on the Health-Related Quality of Life in Children and Their Parents

Purpose To investigate the effect of different myopia severity on the health-related quality of life (QOL) in both children and their parents. Methods Cross-sectional study from October to November, 2021. Age and sex-matched children with binocular emmetropia (−0.5D < spherical equivalence [SE] < 0.5D), low myopia (−5.0D < SE ≤ −0.5D), and high myopia (SE ≤ −5.0D), as well as their parents, were enrolled. All children underwent ocular examinations. The Pediatric Quality of Life Inventory (PedsQL) Generic Core Scales, Version 4 (child-report, 23 items) and the PedsQL Family Impact Module, Version 2 (parent-report, 36 items) was used for QOL assessment of the children and their parents, respectively. Results Forty-one, 48 and 45 age- and sex-matched children with their accompanying parents were included in the emmetropia, low myopia and high myopia group, respectively. Parents in the three groups also did not differ in age, sex, or education level. The median total QOL scores were comparable for emmetropic and low myopic children (96.74 [IQR: 93.48–97.83] vs. 96.74 [IQR: 94.57–98.37]) but were significantly lower for high myopic children (88.04 [IQR: 82.61–92.39], both p < .001). A decreasing trend was observed in the median total QOL for parents in the emmetropia (96.53, IQR: 86.81–100), low myopia (82.30, IQR: 70.83–97.22), and high myopia group (70.83, IQR: 60.42–84.03) (p for trend <.001). The effect of per myopic diopter change on QOL was larger in parents than children (coefficient: 1.48 (95%CI: 1.19–1.78) vs. 2.58 [95%CI: 1.83–3.32]), and parents with higher educational level appeared to have more reduction in QOL (p = .008). Conclusions More severe myopia resulted in a larger QOL decrease in both children and parents. Significantly reduced QOL were identified in children with high myopia and parents of children with any myopia.

Retinal Neurotransmitter Alteration in Response to Dopamine D2 Receptor Antagonist from Myopic Guinea Pigs.

This study aimed to investigate the changes in retinal neurotransmitters and the role of the dopamine D2 receptor (D2R) pathway in regulating the myopic refractive state. Tricolor guinea pigs were randomly divided into two groups: the normal control group (NC) and the form-deprivation myopia group (FDM). Animals in the FDM group had their right eye covered with a balloon for 4 weeks. These two groups were further divided into two subgroups based on intravitreal injection with D2R antagonist sulpiride once a week for 3 weeks (NC, NC-Sul, FDM, and FDM-Sul groups). Ultrahigh-performance liquid chromatography-tandem mass spectrometry was used to quantitatively detect the changes in 17 retinal neurotransmitters. Compared to the NC group, the concentrations of dopamine (DA) and γ-aminobutyric acid (GABA) decreased, while those of glutamate (Glu), 3-methoxytyramine (3-MT), and glycine increased, accompanied by an increase in myopic refraction and axial length (AL) in the FDM group. In the FDM-Sul group, glycine and DA levels were upregulated, whereas 3-MT and Glu levels were downregulated, accompanied by a decrease in myopic refraction and AL. The ratio of Glu to GABA (RGG) represents the balance between excitatory and inhibitory neurotransmitters. Notably, RGG changes occurred with corresponding AL changes, which increased in the FDM group and decreased in the FDM-Sul group. Decreased retinal DA concentration, with an increase in Glu, may be involved in the myopia progression. D2R antagonists might effectively slow myopia progression by increasing retinal DA, regulating Glu concentration to match GABA, and maintaining the balance between excitatory and inhibitory neurotransmitters.

Effects of blue light exposure on ocular parameters and choroidal blood perfusion in Guinea pig

PurposeTo investigate the impact of different duration of blue light exposure on ocular parameters and choroidal blood perfusion in guinea pigs with lens-induced myopia. MethodThree-week-old Guinea pigs were randomly assigned to different light-environment groups. All groups were subjected to 12-h light/dark cycle. The control (NC) group was conditioned without intervention. While lens-induced myopia (LIM) groups had a −10D lens placed in the right eye and 0D in the left eye. The guinea pigs were exposed to increasing periods of blue-light (420 nm) environment for 3,6,9,12 h per day. Changes in refraction, axial length (AL), the radius of corneal curvature (CCR), choroidal thickness (ChT), and choroidal blood perfusion (ChBP)were measured in both LIM-eye and fellow-eye during the second and fourth week of LIM duration. ResultsDuring the first two weeks of the experiment, blue light exposure raised ChBP and ChT, and the effect of suppressing myopia was proportional to the duration of blue light exposure. However, in the fourth week of the experiment, prolonged blue light (12BL) exposure led to a reduction in retinal thickness and the increase in ChT and ChBP ceased. Shorter blue light exposure had a better effect on myopia suppression, with all blue light groups statistically different from the LIM group. ConclusionExposure to blue-light appears to have the potential to improve ChBP and ChT, thereby inhibiting the development of myopia. we speculate that blue-light inhibits the development of myopia for reasons other than longitudinal chromatic aberration (LCA). However,long-term exposure to blue-light may have adverse effects on ocular development. The next step is to investigate in depth the mechanisms by which the rational use of blue light regulates choroidal blood flow, offering new hope for the treatment of myopia.

Changes in anisometropia by age in children with hyperopia, myopia, and antimetropia

Anisometropia is a unique condition of both eyes and it is associated with vision problems such as amblyopia and reduced stereoacuity. Previous studies have not reported its change pattern by age and its correlation with the refractive condition of both eyes. This study aims to compare the changes in anisometropia by age in children with hyperopia, myopia, and antimetropia. In total, 156 children were included. Children aged 3–11 years with anisometropia ≥ 1.00 D were followed up for ≥ 1 year with ≥ 2 visits at two medical centers in Taiwan. Refractive errors by cycloplegic autorefractometry, best-corrected visual acuity, eye position, and atropine use were recorded. The children were divided into hyperopic, myopic, and antimetropic groups. The results showed that anisometropia decreased in children aged < 6 years (3.34–2.96 D; P = 0.038) and increased in older children (2.16–2.55 D; P = 0.005). In children aged 3, 4, 5, and 6 years, the mean anisometropia was higher in children with myopia and antimetropia than in those with hyperopia (P = 0.005, 0.002, 0.001, and 0.011, respectively). The differences were not significant in children aged > 6 years (all P > 0.05). The factors associated with changes in anisometropia were age, refractive group, amblyopia, and strabismus. Anisometropia decreased with age in children younger than 6 years, and the changes in anisometropia was found in children with myopia and antimetropia.

Impact of corrected refractive power on the corneal denervation and ocular surface in small-incision lenticule extraction and LASIK.

To evaluate the impact of corrected refractive power on the corneal denervation and ocular surface in small-incision lenticule extraction (SMILE) and laser in situ keratomileusis (LASIK). Singapore National Eye Center, Singapore. Prospective study. 88 eyes undergoing SMILE or LASIK were divided into low-moderate (manifest refractive spherical equivalent [MRSE] <-6.0 diopters [D]) and high myopic (MRSE ≥-6.0 D) groups. In vivo confocal microscopy and clinical assessments were performed preoperatively and at 1 month, 3 months, 6 months, and 12 months postoperatively. In SMILE, high myopic treatment presented with significantly greater reduction in the corneal nerve fiber area (CNFA) and nerve fiber fractal dimension (CFracDim) compared with low-moderate myopic treatment (both P < .05). There was a significant and negative correlation between the corrected MRSE and the reduction in corneal nerve fiber density (CNFD), corneal nerve branch density (CNBD), corneal nerve fiber length, CNFA, and CFracDim after SMILE (r = -0.38 to -0.66, all P < .05). In LASIK, a significant correlation between the MRSE and the changes in CNBD, corneal nerve fiber total branch density, CNFA (r = -0.37 to -0.41), and corneal nerve fiber width (r = 0.43) was observed (all P < .05). Compared with SMILE, LASIK had greater reduction in CNBD and CNFA for every diopter increase in the corrected MRSE. High myopic SMILE, compared with low-moderate myopic SMILE, resulted in significantly lower tear break-up time at 1 and 6 months (both P < .05). The changes in CNFA and CFracDim were significantly associated with Schirmer test values (both P < .001). Postoperative corneal denervation was related to corrected refractive power in both SMILE and LASIK. With the same refractive correction, LASIK led to more prominent corneal denervation.