Moderate Myopia Research Articles

Transpalpebral intraocular pressure measured by Diaton tonometer before, 1 week, and 1 month after transepithelial photorefractive keratectomy in young myopic Saudi patients and its determinants.

To present changes in transpalpebral intraocular pressure (tpIOP) in eyes after transepithelial photorefractive keratectomy (TPRK) in myopic Saudi patients and its determinants. This one-armed cohort included the myopic eyes of Saudi adolescents treated with TPRK in 2020-2021. The difference in tpIOP before surgery, 1 week after surgery, and 1 month after surgery using Diaton was the main outcome. Central corneal thickness (CCT), myopia grade, gender, age, and corneal epithelial thickness before surgery were independent factors. Matched-pair analysis was conducted. The determinants of tpIOP post-TPRK were studied. Our cohort included 193 eyes of 97 participants (25.6 ± 5.8 years). Mild, moderate, and severe myopia were present in 93, 79, and 21 eyes, respectively. tpIOP was 22 mmHg or more in 5 and 8 eyes at 1-week and 1-month follow-up, respectively. The change in tpIOP ranged from - 7.00 to + 11.0 mmHg at 1 week and - 8.0 to + 26.0 mmHg at 1 month. The median change of CCT at 1 month was 59 μ. Change in tpIOP was not correlated with change in CCT at 1 month (r = -0.107, Pearson P = 0.14). Change of tpIOP was significantly correlated to spherical equivalent (SE) before surgery (matched-pair P < 0.001). SE (Mann-Whitney U P = 0.02) and tpIOP (Mann-Whitney U P = 0.02) before TPRK were significantly correlated to tpIOP >22 mmHg after TPRK. The changes in tpIOP following refractive surgery correlate to the refractive status of the eye and tpIOP before surgery.

Effect of conventional and orthokeratological hard contact lenses on anatomical and functional characteristics of the cornea

This study evaluated the potential effects of conventional hard contact lenses (HCL) and orthokeratological contact lenses (OKL) on anatomical and functional condition of the cornea in myopia correction. The study included 80 patients (159 eyes) with low, moderate and high myopia. Group 1 consisted of 40 patients (79 eyes) who used conventional HCL; group 2 included 40 patients (80 eyes) who used OKL. All patients underwent topographic keratometry, corneal pachymetry mapping (Pentacam, Oculus, Germany; Visante OCT, Carl Zeiss, Germany), high-order aberrometry (OPD Scan, Nidek, Japan), confocal microscopy (Confoscan 4, Nidek, Japan), evaluation of corneal biomechanical properties (ORA, Reichert Technologies, USA) and corneal light scattering (Pentacam, Oculus, Germany). Examinations were taken before the treatment started and after 8-12 months of contact lens wear. Group 1 showed corneal thickness increase in all zones (by 0.9-1.1%), no significant changes in corneal refraction, and increase in corneal hysteresis and corneal resistance factor. OKL wear led to a significant flattening of anterior surface of the cornea and steepening of its paracentral area, decrease in central corneal thickness (by 2.8%) and increase in mid-peripheral thickness (by 2.2%). No significant changes in posterior corneal surface were observed in the study patients. More significant increase in higher-order aberrations and the degree of light scattering was observed in group 2, while changes in subepithelial nerve plexus and stromal structure were more significant in group 1. Long-term OKL wear shows more significant morphological and functional corneal changes compared to RGP lens.

Direct assessment of changes in biomechanical properties of the cornea after ReLEx SMILE and FemtoLASIK surgeries

The SMILE group comprised 23 patients (46 eyes) with spherical refraction -3.8±1.8 diopters (D), the FemtoLASIK group included 18 patients (36 eyes) with spherical refraction -3.5±1.3 D. Analysis of the biomechanical properties of the cornea was carried out using the CORVIS ST device (Oculus, Germany) before and seven days after corneal refractive surgery. In the SMILE group, with intraoperative decrease in corneal thickness of 91.43±19.43 µm, a significant increase in the following parameters was observed: deformation coefficient (DA ratio; p=0.0001), peak distance (PD; p=0.02) and inverse concave radius (ICR; p=0.003); a decrease in the stiffness parameter at first applanation (SP-A1; p=0.0001), Corvis biomechanical index (CBI; p=0.0001), intraocular pressure (IOP; p=0.001). In the FemtoLASIK group, with intraoperative decrease in corneal thickness of 75.33±32.3 µm, we observed a significant increase in DA ratio (p=0.0002), PD (p=0.04), ICR (p=0.0002), a decrease in SP-A1 (p<0.0001), IOP values (p=0.0003). In comparison with the FemtoLASIK group, the deformation amplitude DA changed significantly less in the SMILE group (p=0.04). In the FemtoLASIK group, in comparison with the SMILE group, the DA ratio (p=0.0009) and SP-A1 (p=0.0003) significantly increased. Intraoperative corneal thickness change correlates with ICR both in SMILE (R=0.52) and in FemtoLASIK (R=0.65). Corneal biomechanical properties determined with CORVIS ST in eyes with mild to moderate myopia change to a lesser extent after ReLEx SMILE compared to FemtoLASIK.

Ultra-Widefield Swept-Source Optical Coherence Tomography Angiography in the Assessment of Choroidal Changes in Young Adults With Myopia.

To evaluate choroidal changes in young adults with myopia using ultra-widefield swept-source optical coherence tomography angiography (SS-OCTA). This study enrolled 105 eyes of 105 participants who underwent SS-OCTA imaging (24 mm × 20 mm) centered on the fovea. Eyes were categorized as low myopia, moderate myopia, or high myopia. Choroidal thickness, choroidal capillary plexus (CCP) vessel density, and choroidal Sattler's and Haller's layer (CSHL) vessel density were analyzed in nine grids using built-in angiography analysis software. A significant decrease in choroidal thickness was found in most grids (P < 0.01) in high myopia. The CSHL vessel density also showed a significant decrease in most grids (P < 0.05) in high myopia. Choroidal thickness was negatively correlated with axial length in most grids (P < 0.05). Choroidal thinning was most evident in the macular grid (β = -22.55, P < 0.001). CSHL vessel density was negatively correlated with axial length in most grids (P < 0.05). Choroidal changes could be quantified using ultra-widefield SS-OCTA. Choroidal thinning with increasing axial length indicated regional differences in eyes with myopia, which were most evident in the macular area. Decreased CSHL vessel density with increasing axial length also indicated regional differences in eyes with myopia. This study explored choroidal changes with a wider field of view than has been currently available.

Comparison of anterior corneal aberrations measured by Scheimpflug and Placido Disc System for myopes

BackgroundTo ascertain the agreement of corneal aberrations obtained from the Pentacam and the KR-1W in myopic populations and to investigate the influence of the level of myopia as well as the laterality on the agreement.MethodsIn this observational study, a rotating Scheimpflug camera (Pentacam AXL) and a Hartmann-Shack wavefront analyzer with Placido-disc topographer (KR-1W) were used to measure the aberrations of myopes in the anterior corneal surface by one experienced operator. All examinations were computed across a 6 mm diameter. Six subgroups were generated according to the degree of myopia (mild, moderate, and severe myopia) and the laterality of eyes (right and left eyes).ResultsThe study included 245 eyes of 170 participants. For certain anterior corneal aberrations, statistically significant differences existed between the Pentacam and the KR-1W (all P < .05). The values of Zernike (Z)(2,0), Z(2,2), Z(3,1), and Z(4,0) varied in all levels of myopia regardless of the laterality, with the values of the Pentacam constantly larger than the KR-1W in the measurement of Z(2,0), Z(2,2), and Z(4,0). For 2nd to 6th aberrations, both instruments correlated poorly to moderately. The width of limits of agreement between the two instruments was clinically too wide (> 0.1 μm) for aberrations closely correlated with visual quality, including Z(3, ± 3), Z(3, ± 1), and Z(4,0), and almost all aberrations, indicating poor agreement.ConclusionsIn clinical practice, the Pentacam based on Scheimpflug technology and the KR-1W based on Placido Disc System are not interchangeable in measuring anterior corneal aberration for myopes regardless of myopia degree and the laterality, suggesting that a consistent instrument should be selected for surgical design as well as follow-up.

Changes of the effective optical zone after small-incision lenticule extraction and a correlation analysis.

The objective of the study is to observe the changes in the effective optical zone (EOZ) after small incision lenticule extraction (SMILE) and explore possible correlations with some influencing factors. In total, 133 eyes after SMILE were divided into the mild to moderate myopia group (- 1.75 D to - 5.75 D, 70 eyes) and the high myopia group (- 6.00 D to - 9.50 D, 63 eyes). The postoperative EOZ was calculated by utilizing the corneal tangential curvature map. Changes in EOZ (△-OZ) were monitored and compared between the two groups. Pearson correlation analysis was conducted to determine the correlation between △-OZ and corneal high-order wavefront aberrations. Multicollinearity analysis and ridge regression analysis were performed to assess the correlation between △-OZ and some corneal parameters. After SMILE, the horizontal EOZ (H-EOZ), vertical EOZ (V-EOZ), and average EOZ (A-EOZ) were significantly smaller than the programmed optical zone (POZ) in both groups (p < 0.05). The difference between V-EOZ and POZ (△V-OZ) and the difference between A-EOZ and POZ (△A-OZ) showed more significant changes in the high myopia group than in the mild to moderate myopia group, and △V-OZ was significantly larger than the difference between H-EOZ and POZ (△H-OZ) in the high myopia group. In both groups, the total high-order aberration (T-HOA) and spherical aberration (SA) both increased after SMILE, and they had a similar significant negative correlation with A-EOZ. Moreover, there was a significant negative correlation between △-OZ and Km (X1), Q-value (X2), spherical equivalent (SE, X3), ablating depth (AD, X4) and △e (X6), and a significant positive correlation between △-OZ and △Q (X5). △H-OZ was expressed as Y1, △V-OZ as Y2, and △A-OZ as Y3. The multiple linear regression equations were as follows: Y1 = 3.683 - 0.065X1, Y2 = 1.549 - 0.469X2 - 0.059X3, Y3 = 4.015 - 0.07X1 - 0.03X3, Y1 = 1.337 - 0.005X4 + 0.413X5, Y2 = 1.265 + 0.469X5, and Y3 = 0.852 - 0.002X4 - 0.398X6. The correlation degree with △A-OZ was ranked as Km > △Q > Q-value > AD > e-value > △e > SE > △Km, as represented by the ridge regression analysis. The EOZ was irregularly reduced after SMILE, which should be taken into consideration in the design of POZ, especially for high myopia. Consideration of the refractive diopter and corneal topography is advised for the design of POZ, the latter of which has greater reference significance.

Increasing prevalence of myopia and the impact of education in primary-school students in Xi'an, north-western of China.

The present study was performed to detect the prevalence of myopia among primary-school students in Xi'an, north-western of China. The present study was a school-based study with students aged from 6 to 13 years old. All the individuals underwent ophthalmological examination and spherical equivalent (SE) of refractive error were measured with non-cycloplegic refraction. Myopia was defined as a SE of ≤ -0.5 diopters (D), and further divided into three stratified groups based on SE: low myopia (≤ -0.5 to >-3.0 D), moderate myopia (≤ -3.0 to >-6.0 D), and high myopia (≤ -6.0 D). Relative risk factors, including age, sex, grade and ethnicity were investigated using questionnaire. A total of 4,680 individuals were eligible for this survey and 4,654 (99.4% participation rate) were finally included (51.2% boys). The mean age of participants was 8.756 ± 1.727 years. The whole city-level prevalence of total myopia was 57.1% (95% CI: 55.7-58.6%). Additionally, the prevalence of low, moderate, and high myopia was 45.0% (95% CI: 43.5-46.4%), 11.1% (95% CI: 10.2-12.0%), and 1.0% (95% CI: 0.7-1.3%), respectively. Moreover, grade (education level) instead of age, sex and ethnicity was the most essential risk factor for prevalence of overall myopia (OR = 1.844, 95% CI: 1.605-2.119), and an increase of prevalence by 84.4% per grade was seen. Furthermore, similar associations of grade were significant with low myopia (OR = 1.613, 95% CI: 1.385-1.877) and moderate myopia (OR = 2.186, 95% CI: 1.693-2.823), meanwhile, prevalence of low myopia and moderate myopia demonstrated an increase of prevalence by 61.3 and 118.6% per grade, respectively. None of the factors included in the present study was significant risk factor for high myopia. The present study investigated a non-negligible high prevalence of myopia among primary-school students in Xi'an, north-western of China, and a gradual increasing in proportion with education level.

Risk factors as glaucoma predictors in myopic students

Purpose: identification of early risk factors — predictors of POAG development in students with myopic refraction based on questionnaire and functional test data and the effects of fractal photostimulation (FS). Material and methods. The study involved two clinical groups: the main group of 24 students (48 eyes) with mild to moderate myopia, averagely aged 21.3 ± 0.7 years, and the comparison group (according to FS effects) of 29 patients (58 eyes) with an established diagnosis of stage I–III POAG, averagely aged 58 ± 18 years, and a control group consisting of 66 people (132 eyes, mean age 21.2 ± 1.3 years). The case history of patients and typical complaints were found in questionnaire data. For the two clinical groups, the impact of 10 low-intensity FS sessions was evaluated. Results. A set of features viewed as risk factors for POAG development was determined using the data of the questionaries filled in by the main and comparison groups. The changes in mean IOP values measured before and after an FS course were found to be greater in POAG patients than in myopic students. FS was shown to contribute to IOP stabilization in patients with pre-existing morphological and functional glaucoma changes and the occurrence of accompanying pathologies such as vasospasm, blood pressure fluctuations, and migraine-like pain. After a course of FS, overall photosensitivity increased significantly as compared with the baseline in students with mild and moderate myopia (p &lt; 0.05). Also, a positive effect of an FS course on MD indices in patients with stages IIa and IIIa POAG was confirmed. Conclusion. The research results confirm the need to identify clinical and functional predictors of POAG with a progressive glaucomatous process in students with myopic refraction.

Refractive Effect of Epithelial Remodelling in Myopia after Transepithelial Photorefractive Keratectomy.

(1) Introduction: We analysed epithelial changes after the treatment of moderate myopia with transepithelial photorefractive keratectomy. (2) Materials and Methods: We used optical coherence tomography data and analysed changes in the stroma and epithelium after ablation. We aimed to ascertain how much epithelium hyperplasia occurred after TransPRK; for this, we used data from 50 eyes treated with TransPRK with the AMARIS 1050 Hz, with a minimum follow-up of 4 months. (3) Results: The measured epithelial changes corresponded to a less than 0.1 ± 0.2D of spherical effect, less than 0.2 ± 0.2D of astigmatic effect, and less than 0.5 ± 0.2D of comatic effect. (4) Conclusions: The changes in epithelial thickness after aberration-neutral transepithelial photorefractive keratectomy for moderate myopia were very small, indicating a low level of epithelial hyperplasia without resembling a regression-inducing lentoid.

Congenital myopia

AbstractIntroduction: Acquired myopia – usually known as “myopia” – because of its a very high and growing prevalence, is increasingly discussed in the scientific literature. It shares hardly any feature with congenital myopia, which is a completely distinct entity.Objective: To describe the clinical and pathophysiological characteristics, and management challenges, of congenital myopia.Methods: Literature review using Pubmed and Google Scholar and chosen clinical case series.Results: While temporary and moderate myopia in newborns, especially premature ones, can be considered physiological, congenital high myopia is rare and mostly monogenic. It is almost always characterized by an excessive growth of the globe in utero, leading to a high or very high myopia from birth, quite stable over time after birth. It results from collagenopathies in the vast majority of cases (most often Stickler syndrome); more rarely to proteoglycanopathies or lamininopathies. Rarely, it can result from congenital lens ectopia. In both cases, management is debated and mainly relies on small series of cases. The rate of visual and oculomotor complications is particularly high.Conclusions: Congenital myopia are a challenge for both clinicians and geneticists; recent progress has been achieved in these fields.

A cross-sectional study of association between ocular pressures and different grades of myopia in young adults

Introduction and Aim: My­opia is one of the most common refractive errors causing visual disability worldwide. Uncorrected refractive error poses a public health challenge especially in young adults who have to spend most of their time in literary works. Intra ocular pressure (IOP) is one of the crucial factors intertwined in the pathophysiology of myopia. Ocular perfusion pressure (OPP) determines ocular blood flow. Studies done on association between IOP and refractive errors are contradictory. There is paucity of literature on relationship between OPP and myopia. Hence this original article aimed to assess the association of IOP and OPP changes with myopia and to analyze the relationship between ocular pressures with severity of myopia. Materials and Methods: Hundred normal adults in the age group of 18-24 years of either gender were recruited for the present study. Voluntary written and informed consent was sought from all participants and the refractive power of their eyes was noted. They were categorised into three groups based on the severity of myopia. Controls were the emmetropes. All participants were asked to relax for 5-10 minutes and the resting BP and IOP were recorded using sphygmomanometer and rebound tonometer respectively. OPP was calculated. Results: IOP values were comparatively higher in myopes than emmetropes. A significant reduction in OPP values were observed in moderate myopes. Conclusion: Myopes have a higher IOP suggesting myopia is one of the major risk factor for ocular hypertension. Low OPP values in moderate myopes indicate reduced ocular perfusion, making the progressive myopes highly susceptible to glaucoma.

Clinical observation of orthokeratology with increased compression factor in the treatment of myopia

Objective: To discuss the efficacy and safety of orthokeratology with increased compression factor (ICF) in myopia correction in children. Methods: It was a prospective cohort study. Data of the right eyes of myopic children who visited the First Affiliated Hospital of Chengdu Medical College for orthokeratology were collected continuously from May 2016 to Dec 2018. All children had low myopia (<3.00 D) or moderate myopia (≥3.00 D), and were grouped using random numbers in Excel to receive orthokeratology with ICF or conventional compression factor (CCF). The axial length (AL), spherical equivalent (SE), best corrected visual acuity (BCVA), near visual acuity (NVA), Efron grade, corneal hysteresis (CH), corneal resistance factor (CRF), corneal-compensated intraocular pressure (IOPcc), tear film break-up time (BUT), higher-order aberrations (HOAs), accommodative amplitude (AA) and accommodative facility (AF) were compared between groups during the 1-year treatment period. The Chi-squared test was used to compare the categorical data, while the independent-sample t-test was performed to assess the measurement data. Results: After 1 year of treatment, there were no statistical differences in AL, SE, BCVA, NVA, Efron grade, CH, CRF, IOPcc, BUT, HOAs, AA and AF between the low myopia ICF group and the low myopia CCF group (all P>0.05). After 6 months of treatment, the AL increased by (0.05±0.03) mm in the moderate myopia ICF group and by (0.08±0.04) mm in the moderate myopia CCF group (t=-3.416, P=0.001). After 1 year of treatment, the AL increased by (0.12±0.04) mm in the moderate myopia ICF group and by, (0.16±0.05) mm in the moderate myopia CCF group (t=-4.017, P<0.001). The SE was (-0.16±0.40) D in the moderate myopia ICF group, significantly different from that in the moderate myopia CCF group [(-0.58±0.60) D; t=3.529, P=0.001]. There were also statistical differences in HOAs, spherical aberrations and AF (all P<0.05), but no statistical differences in BCVA, NVA, Efron grade, CH, CRF, IOPcc, BUT and AA between the two groups (all P>0.05). Conclusions: Orthokeratology with ICF safely and effectively corrected myopia in children during the observation period. It could control the progression of moderate myopia more effectively than that of low myopia.

The Effect of Orthokeratology Lens on the Axial Length of Globe in Children with Myopia in Asia

The aim of this meta-analysis was to determine the effect of orthokeratology (OK) lens on the axial length of the eye globe of Asian children with myopia of low and moderate degree compared with children treated with glasses. PubMed, Embase, Web of Science, and Cochrane Library were searched to collect relative researches on the treatment of OK lens in myopia children from January 2000 to July 2021. The authors adopted the standardised mean difference (SMD) as effect size, to estimate the pooled changes of axial length in Asian myopic children. Seven articles were identified. In Asian children with myopia of low to a moderate degree, compared with glasses treatment, axial length decreased significantly in the OK Lens group (SMD = -0.84, 95%CI: -1.10 ~ -0.58), with a p-value less than 0.05. According to the follow-up time, the subgroup analysis demonstrated that, SMD = -0.68 (95%CI: -1.43 ~ 0.08, p>0.05) for six months; SMD = -1.00 (95 %CI: -1.38~-0.62, p<0.05) for 12 months; SMD=-0.71 (95%CI: -1.20~-0.21, p<0.05) for two years. In conclusion, in the early treatment, compared with glasses, children with low and moderate myopia wearing OK lenses were more effective in reducing axial elongation in Asia. Key Words: Axial length, Orthokeratology, Myopia, Meta-analysis.

Comparison of outcome of LASIK in mild, moderate and high myopia

Background: Lasik-Laser in situ keratomileusis is by for the predominant refractive procedure in use today. We are beginning to learn both its full potential and its limitations. This includes refining our knowledge about how much refractive error can be corrected with LASIK while maintaining a high quality of vision. Aim: To evaluate and compare the outcome of LASIK performed in patients with mild, moderate and severe myopia using SCHWIND ESIRIS excimer laser system. Methods: A hospital based, prospective, randomized case study was conducted on 78 eyes of 40 patients underwent LASIK with SCHWIND ESIRIS Laser system of which 40 eyes were of low myopia, 28 eyes were of moderate myopia and 10 eyes were of high myopia at Vinayaka Mission Hospital, Salem, between January-2010 to December-2010. Results: Preoperative &amp; postoperative BCVA was compared which was found to be statistically significant, there was no postoperative decrease in vision during the 6 months follow up. There was no incidence of corneal ectasia during the 6 months. There was no retreatment in this study. Importantly the safety profile of LASIK in the study was found to be excellent.

Implantable collamer lens implantation (ICL) versus small incision lenticule extraction (SMILE) in low to moderate myopia: study protocol for a randomized, non-inferiority trial

BackgroundImplantable collamer lens implantation (ICL) is a form of ‘foldable’ posterior chamber phakic intraocular lens refractive surgery that generally does not impair cornea and natural accommodation. The potential advantages of the ICL over keratorefractive laser procedures include less induction of higher-order aberrations (HOAs) and enhanced retinal image magnification. On the other hand, small incision lenticule extraction (SMILE), currently, one of the most popular refractive surgery procedures, also offers excellent visual outcomes, particularly for eyes with low to moderate amounts of myopia. The aim of this study is to evaluate whether ICL/TICL (toric ICL) is comparable to SMILE for low to moderate myopia in terms of refractive outcomes at 3 and 18 months post-operatively.Methods/designThis is a prospective randomized study. A total of 300 participants will be randomized into two groups, the ICL/TICL group and SMILE group. Eligible participants with spherical equivalent (SE) less than − 6.0 diopter (D) will be recruited. Following randomization, participants will be followed at 1, 3, 6, 12, and 18 months. The primary outcome is the refractive predictability at every postoperative point after surgery, which is the proportion of the number of eyes achieving a postoperative SE within ± 0.5 D and ± 1.0 D of the intended target. Secondary outcome parameters include visual acuity, refraction, adverse events, and quality of vision measurements.DiscussionThis trial will provide information on whether ICL has comparable, if not superior, refractive outcomes compared to the established SMILE for low to moderate myopia, thus providing evidence for translation into clinical practice.Trial registrationChinese clinical trial registry (ChiCTR) 2200055372. Registered on 08 January 2022.

Short-term effect of orthokeratology lens wear on choroidal blood flow in children with low and moderate myopia

We investigated changes in choroidal vascularity and choriocapillaris blood perfusion during orthokeratology (Ortho-K) lens wear. Sixty-two children with low to moderate myopia were enrolled. The Ortho-K group (n = 42) continuously wore Ortho-K lenses for 3 months, and the controls (n = 20) wore single-vision distance spectacles. All of the patients were instructed to return for follow-up visits after 1 day, 1 week and 1 month and 3 months of treatment. The subfoveal choroidal thickness (SFChT), choroidal vascularity [including the total choroidal area, luminal area, stromal area, and choroidal vascularity index (CVI)] and percentage of choriocapillaris flow voids (FV%) were determined with a Cirrus HD-OCT instrument. Additionally, ocular parameters were measured. In the Ortho-K group, the SFChT significantly increased by 12.61 ± 5.90 μm, the CVI was significantly increased by 2.99 ± 2.07% and 3.01 ± 2.32% on the horizontal and vertical scans respectively, and the FV% was significantly decreased by 0.89 ± 0.34% from baseline at the 1-week visit (all p < 0.001). The choroidal parameters remained unchanged at the 1-month and 3-month follow-ups with respect to the 1-week follow-up. In the control group, the choroidal parameters did not change significantly at 1 month (all p > 0.05). At the 3-month visit, the changes in the axial length (AL) and vitreous chamber depth (VCD) were significantly greater in the control group than in the Ortho-K group (0.14 ± 0.23 and 0.03 ± 0.05 mm in AL, 0.15 ± 0.23 and 0.06 ± 0.03 mm in VCD respectively). Our longitudinal study showed several choroidal parameter changes in the early stage in Ortho-K lens wearers with low to moderate myopia, and these changes persisted over 3 months. We speculate that Ortho-K lenses regulate choroidal thickness and blood perfusion, affecting myopia development.

Changes in retinal vascular bifurcation in eyes with myopia

ObjectiveTo evaluate the effect of myopia on retinal vascular bifurcation.MethodsA cross-sectional study that retrospectively analyzed the fundus photographs and clinical data of 493 people who participated in routine physical examinations in Huadong Sanatorium. One eye of each subject was included in the analysis. Retinal vascular bifurcation measurements were extracted by using a validated computer program. One-way ANOVA and analysis of covariance were performed to compare the measurements across high myopia, low to moderate myopia, and non-myopia groups.ResultsThe mean age was 41.83 ± 10.43 years and 63.49% were women. The mean spherical equivalent refraction (SER) was − 4.59 ± 3.07 D. Ninety-nine (20.08%) eyes met the definition of high myopia (SER ≤ -6.0 D), along with 234 (47.46%) low to moderate myopia (-6.0 D < SER <-0.5 D), and 160 (32.45%) non-myopia (SER ≥ -0.5 D). The differences in the arteriolar branching angle, venular branching coefficient, venular asymmetry ratio, venular angular asymmetry, and venular junctional exponent among the three groups remained significant (p < 0.05) after multivariate adjustment. Pairwise comparisons showed arteriolar branching angle and venular angular asymmetry in high myopia were significantly lower than low to moderate myopia (p < 0.001, p = 0.014 respectively) and non-myopia (p = 0.007, p = 0.048 respectively). Venular asymmetry ratio and venular branching coefficient in high myopia were significantly higher than low to moderate myopia (p = 0.029, p = 0.001 respectively) and non-myopia (p = 0.041, p = 0.043 respectively). There was a significant difference in venular junctional exponent between high myopia and low to moderate myopia (p = 0.031).ConclusionThe vascular bifurcation differs in dependence on the myopic refractive error and a significant increase in the difference can be observed in high myopic eyes.

Changes in Anterior Chamber After Myopic and Hyperopic FS-LASIK.

This study evaluated the changes and explored influential factors in the anterior chamber after femtosecond laser-assisted in situ keratomileusis (FS-LASIK) on the basis of patients with different degrees of myopia, refractive status, and age. Patients underwent uneventful FS-LASIK for the treatment of ametropia. All patients with myopia were classified into a low age group (18-40years) or high age group (> 40years). Patients in the low age group (18-40years) were subdivided into myopia and hyperopia groups. According to the preoperative spherical equivalent values, the myopia group was further divided into low myopia, moderate myopia, and high myopia groups. We measured the magnitude of anterior chamber depth (ACD), angle (ACA), volume (ACV), lens rise, central corneal thickness (CCT), and mean pupil power (MPP) of all patients using Sirius (version 3.2, CSO, Italy) before and 3months post operation. A total of 140 eyes of 87 patients were evaluated. The magnitudes of ACD, ACA, and ACV decreased significantly postoperatively in both low age (P < 0.001, P < 0.001, P < 0.001, respectively) and high age group (P < 0.001, P < 0.001, P < 0.001, respectively) of patients with myopia, while an increasing tendency of ACD (2.85 ± 0.38mm preoperatively vs 2.89 ± 0.09mm postoperatively) and ACA (39.16° ± 7.30° preoperatively vs 39.37° ± 7.68° postoperatively) was found in hyperopia. There was no correlation between different degrees of myopia and the changes in the anterior chamber. Anterior chamber parameters decreased significantly and approximately in the same degree in low and high age groups postoperatively, while an increasing tendency of ACD and ACA was found in hyperopia, indicating that it is probably a corneal magnification effect that influences changes in the anterior chamber.

Posterior chamber toric implantable collamer lenses vs LASIK for myopia and astigmatism: systematic review.

This systematic review compares the visual and refractive outcome of laser in situ keratomileusis with (toric) implantable collamer lens (ICL) in the treatment of myopic astigmatism. An electronic literature search led to 19 comparative articles. Refractive outcome, efficacy, safety, predictability, and stability as well as differences in contrast sensitivity and higher-order aberrations (HOAs) were analyzed for moderate (-3 to -6 diopters [D]) and high (≥-6 D) myopia. Results were either significantly in favor of (toric)-ICL or equal. Fewer HOAs and better contrast sensitivity after (toric)-ICL seem to be the largest asset in its refractive and clinical superiority. However, longer follow-up studies are indicated, specifically for systematically comparing long-term adverse effects.

Effect of orthokeratologic lenses of individual design on visual functions in premature babies with myopia in school age

The study included 62 children aged 6 to 14 years with mild to moderate myopia, born at 28-34 weeks of gestation with a birth weight of 970 to 2200 g. Selection criteria: corneal refractive power &gt;46.00 D, no keratoconus or macular degeneration. The main group – 32 children (64 eyes), who were assigned orthokeratologic lenses, the control group – 30 children (60 eyes) – glasses users. Differences between the groups were not significant. Observation period was 3 years. There were no complications. Corrected visual acuity in the main group increased from 0.63±0.08 to 0.98±0.06, in the control – from 0.61±0.05 to 0.73±0.05; p&lt;0.005. Stable restoration of binocular vision was observed in all children of the study group and 83% of children in the control one. Reserves of absolute accommodation in the main group during the observation period increased by 6.7±0.38 D, and in the control group – by 2.3±0.42 D (p&lt;0.001), which is explained by the active use of accommodation by children of the main group. After 3 years of observation in the main group, the anteroposterior size of the eyeball, according to echobiometry data, almost did not change (from 22.32±0.9 to 24.02±1.1 mm, p&gt;0.2), and in the control group, the eye elongation was more pronounced: from 22.45±0.8 to 25.94±0.9 mm (p&lt;0.01). Complete stabilization of myopia was observed in 30 children (93.75%) of the study group. Orthokeratological lenses MoonLens can be used in patients with high corneal curvature; their use in prematurely babies with a high refractive power of the cornea (&gt;46.0 D) allowed to obtain better results of the treatment.