Myopia Group Research Articles

Determination of depression, anxiety, and hopelessness levels in adolescents with refractive errors after the COVID-19 pandemic

Background/Aim: The prevalence of myopia is increasing worldwide especially among adolescents. Changes in living conditions such as reduced engagement in outdoor activities as well as increased activities near the workplace like reading, writing, and screen exposure are thought to be responsible for this increase. Adolescence is a sensitive period of rapid changes in psychological, physiological, and social aspects. Mental health issues such as anxiety and depression are common during this period. During the pandemic, mental health issues among children and adolescents increased due to stress caused by the disease, social isolation, disruption of routines, and the loss of loved ones. With the rapid increase in myopia among adolescents, there is a need to investigate the effects of myopia on mental health. The aim of this study is to evaluate anxiety, depression, and hopelessness levels in adolescents with myopia after the COVID-19 pandemic and to examine the relationship between myopia and anxiety, depression, and hopelessness. Methods: This was a case-control study that included 40 myopic adolescents aged 16-19 with a spherical refractive degree of -2 diopters (D) and above and 40 emmetropic (no refractive error). Participants who had previously undergone refractive surgery, had binocular visual acuity less than 1.0, had strabismus and amblyopia, had a diagnosis of glaucoma, had undergone ocular surgery for any reason, had retinopathy, or had an astigmatic refractive degree greater than ±0.50 were excluded from the study. The study did not include patients with chronic physiological or psychiatric diseases. Both groups were administered the Automatic Thoughts Questionnaire (ATQ), Coronavirus Anxiety Scale (CAS), Beck Hopelessness Scale (BHS), and Beck Depression Inventory (BDI). The groups were compared according to the scales. Myopic degrees were compared with mixed-effect linear models according to scale categories, and the relationship between ATS scores and myopia degrees was evaluated using the Spearman correlation coefficient. Results: The mean (SD) spherical refractive power of myopic adolescents was -3.156 (1.40) diopters; 62.5% of participants with myopia had been exposed to COVID-19, and the anxiety rate in myopic participants compared to controls was 15% (P=0.026). However, no significant difference was found between the myopia and control groups in terms of automatic thoughts, hopelessness, and depression inventory scores when comparing the groups. No correlation was found between the CAS (F=1.098), BHS (F=1.610), BDI (F=1.699), and ATQ (r=0.151) scales and the increase in myopia when we performed linear mixed model analysis and Spearman correlation analysis. There was no significant relationship between the degree of myopia and automatic thoughts, hopelessness anxiety, and depression. Conclusion: The results indicate that adolescents with myopia had higher levels of anxiety after the COVID-19 pandemic. There was no significant correlation between the degree of myopia and anxiety, depression, hopelessness, and automatic thoughts. It is important to monitor adolescents with myopia carefully during pandemics and provide the necessary mental health support. This is because offering mental health support to myopic young people may protect them from potential lasting emotional problems in adulthood during potential future pandemics. It may be beneficial for adolescents to increase their engagement in outdoor activities to reduce myopia and anxiety.

Correlation between refractive errors and ocular biometric parameters in children and adolescents: a systematic review and meta-analysis

BackgroundRefractive errors are one of the most common ocular conditions among children and adolescents, with myopia showing an increasing prevalence and early onset in this population. Recent studies have identified a correlation between refractive errors and ocular biometric parameters.MethodsA systematic search was conducted in electronic databases including PubMed, EMBASE, Cochrane Library, Web of Science, and Medline from January 1, 2012, to May 1, 2023. Various ocular biometric parameters were summarized under different refractive states, including axial length (AL), central corneal thickness (CCT), anterior chamber depth (ACD), lens thickness (LT), corneal curvature (CC), Corneal curvature radius (CR),axial length-to-corneal radius ratio (AL/CR ratio), choroidal thickness (ChT), retinal thickness (RT), retinal nerve fiber layer thickness (RNFL), and retinal blood density (VD). The differences in these parameters among different refractive states were analyzed using Stata software with fixed or random-effects models, taking into account the assessed heterogeneity level.ResultsThis meta-analysis included a total of 69 studies involving 128,178 eyes, including 48,795 emmetropic eyes, 60,691 myopic eyes, 13,983 hyperopic eyes, 2,040 low myopic eyes, 1,201 moderate myopic eyes, and 1,468 high myopic eyes. The results of our study demonstrated that, compared to the control group (emmetropic group), the myopic group and low, moderate, and high myopic groups showed significant increases in AL, AL/CR ratio, and ACD, while the hyperopic group exhibited significant decreases. Compared to the control group, the myopic group had a significantly increase for CC, while CR, CCT, perifoveal RT, subfoveal ChT, foveal ChT, parafoveal ChT, perifoveal (except nasal) ChT, and pRNFL (except temporal) significantly decreased. Compared to the control group, the hyperopic group had a significantly increase for subfoveal ChT, foveal ChT, parafoveal ChT, perifoveal ChT, and nasal pRNFL. Compared to the control group, the low and moderate myopic groups had a significantly decreases for the CCT, parafoveal RT (except nasal), perifoveal RT (except nasal), and pRNFL (except superior and temporal). Compared to the control group, the high myopic group had a significantly increase for CR, while LT, perifoveal ChT (except nasal), parafoveal RT, perifoveal RT, and pRNFL (except temporal) had significant decreased.ConclusionThe changes of ocular biometric parameters in children and adolescents are closely related to refractive errors. Ocular biometric parameters devices, as effective non-invasive techniques, provide objective biological markers for monitoring refractive errors such as myopia.

Myopia & painful muscle form of temporomandibular disorders: connections between vision, masticatory and cervical muscles activity and sensitivity and sleep quality

The main aim of this study is to evaluate the effects of painful muscle form of temporomandibular disorders and myopia on the connections between the visual organ, the bioelectrical activity and sensitivity of the masticatory and cervical muscles, and sleep quality. Subjects were divided into 4 groups (Myopia & TMDs, Myopia (Without TMDs), Emmetropic & TMDs and Emmetropic (Without TMDs)). The study was conducted in the following order of assessment: examination for temporomandibular disorders, assessment of the muscle activity by electromyograph, pressure pain thresholds examination, ophthalmic examination and completion of the Pittsburgh Sleep Quality Index. It was observed that the Myopia & TMDs group had higher muscle tenderness, higher resting and lower functional muscle bioelectrical activity. The visual organ is clinical related to the masticatory and cervical muscles. TMDs and myopia alter masticatory and cervical muscle activity. The thickness of the choroid in people with myopia is related to muscle tenderness. TMDs and myopia impair sleep quality. It is recommended to determine the number of people with refractive error and its magnitude in the sEMG study in order to be able to replicate the research methodology.

Quantitative analysis of optic disc changes in school-age children with ametropia based on artificial intelligence.

To explore changes in the optic disc and peripapillary atrophy (PPA) in school-age children with ametropia using color fundus photography combined with artificial intelligence (AI) technology. Based on the retrospective case-controlled study, 226 eyes of 113 children aged aged 6-12y were enrolled from October 2021 to May 2022. According to the results of spherical equivalent (SE), the children were divided into four groups: low myopia group (66 eyes), moderate myopia group (60 eyes), high myopia group (50 eyes) and emmetropia control group (50 eyes). All subjects underwent un-aided visual acuity, dilated pupil optometry, best-corrected visual acuity (BCVA), intraocular pressure, ocular axis measurement and color fundus photography. The width of PPA, horizontal diameter ratio of PPA to the optic disc and area ratio of PPA to the optic disc were significantly different among the four groups (P<0.05). The width of the nasal and temporal neuroretinal rim, the roundness of the optic disc, the height of PPA, the vertical diameter ratio of PPA to the optic disc, and the average density of PPA in the high myopia group were significantly different compared with the other three groups (P<0.05). There were strong negative correlations between SE and area ratio of PPA to the optic disc (r=-0.812, P<0.001) and strong positive correlation between axial length (AL) and area ratio of PPA to the optic disc (r=0.736, P<0.001). In school-age children with high myopia, the nasal and temporal neuroretinal rims are narrowed and even lost, which have high sensitivity. The area ratio of the PPA to the optic disc could be used as an early predictor of myopia progression, which is of great significance for the development prevention and management of myopia.

Exploration of the pathophysiology of high myopia via proteomic profiling of human corneal stromal lenticules

This study aimed to investigate the underlying pathophysiology of high myopia by analyzing the proteome of human corneal stromal lenticule samples obtained through small incision lenticule extraction (SMILE). A total of thirty-two patients who underwent SMILE were included in the study. Label-free quantitative proteomic analysis was performed on corneal stromal lenticule samples, equally representing high myopia (n = 10) and low myopia (n = 10) groups. The identified and profiled lenticule proteomes were analyzed using in silico tools to explore biological characteristics of differentially expressed proteins (DEPs). Additionally, LASSO regression and random forest model were employed to identify key proteins associated with the pathophysiology of high myopia. The DEPs were found to be closely linked to immune activation, extracellular matrix, and cell adhesion-related pathways according to gene ontology analysis. Specifically, decreased expression of COL1A1 and increased expression of CDH11 were associated with the pathogenesis of high myopia and validated by western blotting (n = 6) and quantitative real time polymerase chain reaction (n = 6). Overall, this study provides evidence that COL1A1 and CDH11 may contribute to the pathophysiology of high myopia based on comparative proteomic profiling of human corneal stromal lenticules obtained through SMILE.

Comparison of errors in ablation depth calculation after myopic femtosecond laser in situ keratomileusis in patients with different degrees of myopia: a prospective study

BackgroundTo investigate the difference between the predicted preoperative corneal ablation depth and the measured ablation depth for femtosecond laser in situ keratomileusis (FS-LASIK) in patients with different degrees of myopia, and to analyze the source of the difference.MethodsA total of 55 patients (109 eyes) were included in this study. Multiple logistics regression was applied to analyze the sources affecting postoperative refractive outcomes. The difference between the preoperative predicted corneal ablation depth and the 1-day postoperative ablation depth in patients with different degrees of myopia was explored using linear regression. Corneal biomechanical parameters influencing error in ablation depth calculation were examined using multiple linear regression.ResultsOne hundred and nine eyes were divided into low to moderate myopia (55 eyes, myopia of 6 D or less), high myopia (45 eyes, myopia ranging from 6 D to a maximum of 9 D), and very high myopia group (9 eyes, myopia greater than 9 D) based on preoperative refractive error (spherical equivalent). Postoperative visual outcomes were comparable among the three groups of patients, with no significant difference in uncorrected visual acuity (UCVA). We did find notable disparities in spherical equivalent (SE) and central corneal thickness (CCT) in patients with different degrees of myopia at 1 day postoperatively (all p < 0.001). Logistic regression analysis showed that error in ablation depth calculation was an independent risk factor for refractive outcomes one day after surgery (OR = 1.689, 95% CI: 1.366 – 2.089). There was a substantial discrepancy in error in ablation depth calculation at 1 day postoperatively between the three groups. The measured ablation depth of the laser platform was lower than the predicted ablation depth in the low to moderate myopia and very high myopia groups, but the opposite was true in the high myopia group. Pre-operative SE (p < 0.001) and corneal front minimum radius of curvature (Front Rmin) (p = 0.007) obviously influenced the error in ablation depth calculation.ConclusionsError in ablation depth calculation values vary significantly between patients with different degrees of myopia and correlate highly with preoperative SE and Front Rmin. At the same time, the available evidence suggests that error in ablation depth calculation is an influential factor in postoperative refractive status, so it is imperative to control error in ablation depth calculation.

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.&#x0D; 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. &#x0D; 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 &lt; 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).&#x0D; 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.