Severe Myopia Research Articles

Clinical profile and distribution of peripheral retinal changes in myopic population in a hospital-based study in North India.

Purpose:To evaluate the prevalence of different types of peripheral retinal changes in a myopic population in North India and correlate them with axial length.Methods:This cross-sectional, hospital-based survey included 600 eyes of 300 myopic individuals, aged between 10 and 40 years, attending the outdoor ophthalmology clinic of a tertiary eye care hospital in North India were examined from July 2019 to July 2020. They were divided into mild, moderate, high, and severe myopia according to the spherical equivalent of refraction. Axial length was recorded. Peripheral retinal changes were examined by scleral indentation binocular indirect ophthalmoscopy. Standardized findings considered with their fundus location were lattice degeneration, white without pressure and white with pressure, snail-track degenerations, peripheral chorioretinal atrophy, retinal holes, tears, and detachment. The study was approved by the institutional ethics committee, and all participants provided informed consent.Results:Peripheral retinal degenerations were found in almost half (53%) of all myopes included in the study. The most common peripheral retinal degeneration found was lattice degeneration, followed by white without pressure, white with pressure, and chorioretinal atrophy. Most of the peripheral retinal degenerations were seen in the temporal quadrant of the fundus, either superotemporal or inferotemporal. There was a significant positive association between the prevalence of peripheral retinal degeneration with age, increased axial length, and severity of myopiaConclusion:The results of our study indicate the necessity for careful peripheral fundus examinations of all myopes, irrespective of age and degree of myopia, for early diagnosis and better management of visual-threatening complications like retinal detachment.

The Comparison of Transepithelial versus Conventional Photorefractive Keratectomy

Introduction : Photorefractive keratectomy (PRK) is the first choice in treating myopia for eyes with mildly irregular and/or thin corneas because it preserves corneal integrity. A laser-assisted method for epithelial removal, termed Transepithelial PRK (T-PRK), was introduced as an alternative to conventional PRK, which gives a smoother corneal surface than that achieved with mechanical ablation of the epithelium in conventional PRK. Objective: To compare emmetropization between patients treated with T-PRK and conventional PRK. Methods: This study was an observative comparative analytic study with case-control study design. Myopic eyes treated by T-PRK (study group) were compared with variable-adjusted eyes treated by conventional PRK (control group), from year 2015-2018 at Dr.YAP Eye Hospital Yogyakarta. Patients were divided into 3 groups based on the degree on myopia; mild (spherical minus 0-3D), moderate (4-6D), and severe (>7D). Emmetropization within 1 month follow-up and treatment time were analyzed. Results: In all of the cases reviewed, the total percentage of patients treated with T-PRK who reached emmetropization within 1 month follow-up was 21.51% (17/79 eyes), with 33.34% (9/27 eyes) in mild, 28.57% (6/21 eyes) in moderate, and 6.45% (2/31 eyes) in severe myopia group; compared to the control group which was 22.78% (18/79 eyes) (p=0.848), with 48.14% (13/27 eyes) in mild, 15% (3/20 eyes) in moderate, and 6.25% (2/32 eyes) in severe myopia group. Treatment time in the study group was relatively faster compared to the control group. Conclusions: The study group showed slightly better result in treating moderate myopia within 1 month follow-up. Treatment time was relatively faster compared to the control group.

EP006: Homocystinuria in an adolescent patient with Chr21q22.2q22.3 deletion

Homocystinuria is characterized by skeletal manifestations (tall stature, dolichostenomelia, scoliosis, and pectus excavatum), ophthalmologic problems (ectopia lentis, severe myopia), vascular thromboembolism, and intellectual disability. Other features sometimes seen include: seizures, psychiatric problems, extrapyramidal signs, hypopigmentation of the skin and hair, malar flush, livedo reticularis, and pancreatitis.

Oculodentodigital Dysplasia: A Cause of Hypomyelinating Leukodystrophy in Adults.

A middle-aged patient presented with mild facial dysmorphisms, small teeth with enamel hypoplasia, progressive gait disturbances, memory problems, and history of syndactyly, corrected in early childhood. MRI showed a hypomyelination pattern compatible with oculodentaldigital dysplasia (ODDD)1,2 (Figure 1). Ophthalmic findings revealed severe bilateral myopia. Exome sequencing revealed a heterozygous GJA1 missense variant ( p .Gly138Asp). The patient's mother (deceased) had developed slowly progressive neurodegeneration, ataxia, and seizures. MRI (age 80) revealed extensive leukodystrophic changes (Figure 2). ODDD diagnosis is often missed, highlighting the importance of clinical suspicion, MRI, and molecular testing in adult patients with facial, dental, and neurologic clinical features.

Evaluation of Corneal Higher- Order Aberrations in Adults with Different Refractive Status

Purpose: The aim of this study is to evaluate the root mean square error (RMS) of corneal higher- order aberrations in Syrian adult population in different refractive status (emmetropia, myopia, hyperopia and simple myopic astigmatism). Methods: This cross- sectional study was conducted at Tishreen University Hospital in Latakia, Syrian Arab Republic. A total of 420 patients (840 eyes), ages 18- 40 years, participated in the study. Refraction was measured with an autorefractor keratometer and expressed as a spherical equivalent. Total corneal higher- order aberrations (Coma, Spherical Aberration, Trefoil) were measured using Sirius Corneal Topography at a pupil diameter of 5 mm. Results: RMS of Coma and Spherical aberrations peaked in the hyperopia group (0.18 ± 0.08, 0.11 ± 0.02) respectively. Whereas, Trefoil was higher in the severe myopia and simple myopic astigmatism groups (0.25 ± 0.05, 0.25 ± 0.08) respectively. Conclusions: Among a Syrian population, some types of refractive status were associated with certain types of higher- order aberrations, with a significant increase in trefoil in severe myopia and simple myopic astigmatism.

C59. Management of Subacute Painless Aortic Dissection Stanford A Debakey II in Patient With Undiagnosed Marfan Syndrome During Pregnancy

Abstract Background Pregnant women with Marfan’s syndrome needed multidisciplinary approach to evaluate pregnancy status, fetal and maternal outcome. Marfan’s syndrome was an inherited autosomal dominant with mutation of fibrillin-I (FBN1) gene. Pregnant woman with MFS can lead to aortic dissection. It’s increase 23% of maternal mortality and 35% of fetal death. Case Summary a 30 year-old pregnant woman referred from secondary hospital care with valvular heart disease (severe aortic regurgitation due to dilatation of the aortic root and severe mitral regurgitation). Due to her severe myopia, history of aortic dissection in her family, enlarged of aortic root, pulnus excavatum, scoliosis and arachnodactyly, de novo MFS was suspected. She was diagnosed with marfan’s syndrome according her systemic score was 10 (posive >7), and calculated aortic z score was 6.2 (positive >2). Intimal tears and dilatation of the aortic root were considered to terminate the pregnancy. It’s can result bad neonatal outcome. For the management of a potential vascular catastrophe , monitoring of delivery and repairing the aortic root, we needed to multidisciplinary approach. Discussion Patient with marfan’s syndrome during pregnancy, may develop painless aortic dissection because massive dilatation of aortic arch prevent compression of pain sensitive structure. Less evidence to manage pregnant woman with MFS with aortic root dilatation more than 45 mm and or progressively dilatation of aortic root ( more than 0.5 mm/year). This patient was categorized as class IV modified WHO classification with high risk maternal mortality and severe morbidity.

C59. Management of Subacute Painless Aortic Dissection Stanford A Debakey II in Patient With Undiagnosed Marfan Syndrome During Pregnancy

Abstract Background Pregnant women with Marfan’s syndrome needed multidisciplinary approach to evaluate pregnancy status, fetal and maternal outcome. Marfan’s syndrome was an inherited autosomal dominant with mutation of fibrillin-I (FBN1) gene. Pregnant woman with MFS can lead to aortic dissection. It’s increase 23% of maternal mortality and 35% of fetal death. Case Summary a 30 year-old pregnant woman referred from secondary hospital care with valvular heart disease (severe aortic regurgitation due to dilatation of the aortic root and severe mitral regurgitation). Due to her severe myopia, history of aortic dissection in her family, enlarged of aortic root, pulnus excavatum, scoliosis and arachnodactyly, de novo MFS was suspected. She was diagnosed with marfan’s syndrome according her systemic score was 10 (posive >7), and calculated aortic z score was 6.2 (positive >2). Intimal tears and dilatation of the aortic root were considered to terminate the pregnancy. It’s can result bad neonatal outcome. For the management of a potential vascular catastrophe , monitoring of delivery and repairing the aortic root, we needed to multidisciplinary approach. Discussion Patient with marfan’s syndrome during pregnancy, may develop painless aortic dissection because massive dilatation of aortic arch prevent compression of pain sensitive structure. Less evidence to manage pregnant woman with MFS with aortic root dilatation more than 45 mm and or progressively dilatation of aortic root ( more than 0.5 mm/year). This patient was categorized as class IV modified WHO classification with high risk maternal mortality and severe morbidity.

Real-World Visual Outcomes of Laser and Anti-VEGF Treatments for Retinopathy of Prematurity

To characterize visual outcomes in children screened for retinopathy of prematurity (ROP). Retrospective, interventional case series. Patients who received ROP screening examinations at UCLA Medical Centers and were followed with outpatient eye examinations at Stein Eye Institute and/or Doheny Eye Institute (Los Angeles, California) were included. Data were collected on birth characteristics, worst type of ROP, and ROP treatment. Adverse visual outcomes included myopia, strabismus, amblyopia, macular dragging, and optic atrophy. Snellen visual acuity was reported for children 4 years and older. A total of 175 infants (350 eyes) were included for analysis (mean gestational age=28.2 weeks and birth weight=1059 g) from a screening population of 539 infants (1078 eyes, 32.4% follow-up) over a 9-year period. Fifteen eyes received primary anti-vascular endothelial growth factor (anti-VEGF) therapy, whereas 59 eyes received primary laser therapy. Primary anti-VEGF therapy, as compared with primary laser treatment, was associated with a decreased incidence of amblyopia (adjusted odds ratio [aOR]=0.6-0.86, P < .0001) after controlling for gestational age and birth weight. The rates of optic atrophy (P=.79), strabismus (P=.98), and myopia (P=.93) were not different between anti-VEGF and laser treatment groups. Infants receiving anti-VEGF therapy had more posterior disease than laser-treated infants (P=.041). Infants receiving laser therapy were more likely to have severe myopia (aOR=1.02-1.3, P=.023), amblyopia (aOR=1.12-1.61, P=.002), and optic atrophy (aOR=1.01-1.32, P=.045) than infants not treated. These findings add to the advantages of anti-VEGF treatment compared with primary laser treatment, particularly in posterior ROP.

Association between refractive errors and horizontal strabismus: the Korea National Health and Nutrition Examination Survey

To investigate the association between refractive error and horizontal strabismus based on a Korean population-based survey. The study included 22,887 participants >5 years of age who participated in the Korea National Health and Nutrition Examination Survey (KNHANES) from 2008 to 2011. Refractive error was classified into myopia, hyperopia, astigmatism, and anisometropia. The association between refractive error and exodeviation or esodeviation was assessed using multivariate logistic regression analysis. After adjusting for potential confounders, the analyses revealed an increased odds ratio (OR) for exodeviation with an increasing trend according to the severity of myopia (mild myopia, OR = 1.36 [95% CI, 1.11-1.66]; moderate myopia, OR = 1.75 [95% CI, 1.36-2.26]; severe myopia, OR = 2.01 [95% CI, 1.50-2.69]; Ptrend < 0.001). Hyperopia was not associated with exodeviation (P = 0.273). There were also significant associations for exodeviation with astigmatism (OR = 1.36 [95% CI, 1.16-1.59; P < 0.001]) and anisometropia (OR = 1.78 [95% CI, 1.38-2.30; P < 0.001]) In comparison, esodeviation was significantly associated with hyperopia (OR, 10.24 [95% CI, 4.43-23.70; P < 0.001]) and anisometropia (OR, 5.16 [95% CI, 2.27-11.76; P < 0.001]), while no significant association was found with myopic degree (P = 0.170) or astigmatism (P = 0.816). Refractive error was closely associated with exodeviation and esodeviation. These risk associations should be considered when managing refractive errors.

Visumax Femtosecond Laser Impact on Myopic Residual Refractive Error

Background: Compare the residual refractive power following “small incision lenticule extraction” (SMILE) surgical correction in myopic patients with moderate to severe myopia and myopic astigmatism. Aim: To study the pre op with post op residual refractive status comparison in low to high myopia and myopic astigmatism patients under gone ReLEx SMILE operation. Methods: Prospective comparative analysis with 65 eyes of 33 patients classified into three groups19: mild myopia -1.00 to -3.00 D, moderate myopia -3.25 to -6.00 D, and high myopia -6.25 to -10.00 D, comprising spherical and cylindrical using spherical equivalent (SE). Using the SMILE surgery, each patient were corrected for myopic refractive error. Retinoscope was conducted preoperatively and postoperatively one day and one month following surgery, respectively. Results: Pre op 1 day and 1 month are showing a significant and gradual decrease where low and high myopia are compared, which is statistically significant for both one day (0.007) and one month (0.001) post operatively, but low to moderate (0.282) and moderate to high (0.147) post operatively 1 day and 1 month it is not statistically significant. This indicates that high myopia has greater residual power than low and moderate myopia. Conclusion: This research concludes that residual power increases as myopia increases in severity. As the objective residual power after SMILE surgery is less than +/- 0.50D in approximately 75% - 80% of eyes, SMILE surgery is a suitable alternative for refractive surgery correction with less complications than other refractive surgery techniques.

Особенности системного цитокинового статуса при катаракте в сочетании с миопией средней и высокой степени

Актуальность. Катаракта среди причин слепоты занимает одно из ведущих мест. Сочетание катаракты и миопии средней и высокой степени встречается в 45 раз чаще, чем при других видах рефракции. В основе патогенеза многих дистрофических заболеваний глаз лежат нарушения иммунного регулирования. Дистрофические нарушения у пациентов с неосложненной пресенильной катарактой, с миопией средней и высокой степени сопровождаются изменениями содержания цитокинов на местном и системном уровнях. В патогенезе развития катаракты и сочетания катаракты с миопией средней и высокой степени роль про- и противовоспалительных цитокинов остается пока не раскрытой. Цель исследования: изучить особенности системного цитокинового статуса при катаракте в сочетании с миопией средней и высокой степени. Материалы и методы. Изучено содержание провоспалительных и противовоспалительных цитокинов в сыворотке крови у 24 пациентов с катарактой и у 33 больных с катарактой в сочетании с миопией средней и высокой степени. Определение содержания цитокинов (провоспалительных интерлейкинов (ИЛ)-1β, ИЛ-6, противовоспалительных ИЛ-4, ИЛ-10) проведено в сыворотке крови методом твердофазного иммуноферментного анализа с помощью тест-систем «Вектор-Бест». Результаты. Отмечается увеличение содержания провоспалительных цитокинов (ИЛ-1β при миопии — в 6,3 раза (p &lt; 0,05) по сравнению с контрольной группой, а ИЛ-6 — в 6,5 раза (р &lt; 0,05)). Противовоспалительные цитокины ИЛ-4, ИЛ-10 у пациентов обеих групп в пределах референтных значений. Содержание ИЛ-4 у пациентов основной группы незначительно меньше, чем у пациентов контрольной группы. Цитокиновый индекс у пациентов основной группы выше, чем в контрольной. Выводы. Установлено, что у больных с катарактой в сочетании с миопией средней и высокой степени имеется нарушение системного цитокинового баланса.

Clinical Utility of Bruch Membrane Opening-Minimum Rim Width for Detecting Early Glaucoma in Myopic Eyes.

Bruch membrane opening-minimum rim width (BMO-MRW) is overall a useful parameter for diagnosing early glaucoma in myopic eyes. The aim of this study was to determine the diagnostic value of BMO-MRW compared with peripapillary retinal nerve fiber layer (pRNFL) thickness for detecting early glaucoma in patients with moderate to severe myopia. One eye was randomly selected from each of the 253 subjects (127 normal controls, 82 with glaucoma suspect, and 44 with early glaucoma). All patients underwent visual acuity testing, refractive error assessment, slit-lamp inspection, intraocular pressure measurement, fundus photography, perimetry. BMO-MRW and pRNFL thickness data were obtained using spectral-domain optical coherence tomography. Area under the receiver operating characteristic curves (AUC) for global and sectoral thickness parameters were calculated. Global analyses for the discrimination of early glaucoma in all myopic subjects showed comparable AUCs between BMO-MRW and pRNFL thickness [AUC 0.952 (95% confidence interval, 0.918-0.975) and 0.934 (95% confidence interval, 0.896-0.961), respectively, P=0.345]. However, in sectoral analysis, BMO-MRW showed significantly better diagnostic performance than pRNFL thickness except for the superotemporal sector. The AUC for discriminating early glaucoma from glaucoma suspect, BMO-MRW showed statistically better diagnostic performance in the inferotemporal, inferonasal, superonasal, and nasal sectors. When dividing the subject based on a threshold Bruch membrane opening (BMO) area of 2.5 mm2, the diagnostic power of BMO-MRW was generally lower except for the inferonasal sector in the subgroup with a large BMO area. BMO-MRW was overall a useful parameter for diagnosing early glaucoma in myopic eyes. However, its diagnostic performance was decreased in myopic eyes with large BMO and there were no significant differences from pRNFL thickness.

Prevalence of myopia in 3\u201314-year-old Chinese children: a school-based cross-sectional study in Chengdu

BackgroundThe prevalence of myopia among children in Chengdu is unknown. The aim of this study was to determine the prevalence of myopia in 3- to 14-year-old Chinese children in Chengdu.MethodsThis study was a school-based cross-sectional study in children aged 3–14 years. Visual acuity (VA), spherical equivalent error (SER) with noncycloplegic autorefraction, axial length (AL) and corneal radius (CR) were measured.ResultsA total of 19,455 children were recruited for this study. The prevalence of myopia was 38.1 %; the prevalence of low myopia was 26.6 %, that of moderate myopia was 9.8 %, and that of high myopia was 1.7 %. The prevalence of myopia and SER increased with age from 6 years old. The prevalence of myopia was higher, and the SER indicated more severe myopia in the girls than in the boys (40.1 % vs. 36.2 %, χ2 = 30.67, df = 1, P < 0.001; -0.93 D ± 1.75 D vs. -0.84 D ± 1.74 D, t = 3.613, df=19,453, P < 0.001). The girls had a higher prevalence of myopia and myopic SER than did the boys aged 9 years and older (P < 0.05). Among the myopic children, the rates of uncorrected, undercorrected and fully corrected myopia were 54.8 %, 31.1 and 14.1 %, respectively. AL and AL/CR increased with age from 6 years old, but CR remained stable after 4 years old. The AL was longer, and the CR was flatter in the boys than in the girls aged 3 to 14 years old (P < 0.05).ConclusionsThe prevalence of myopia, AL and AL/CR increased, and the SER became more myopic with age from 6 years old. The girls had a higher prevalence of myopia and myopic SER than did the boys, but the boys had a longer AL, flatter CR and higher AL/CR ratio than did the girls. The rate of uncorrected myopia was very high in the myopic children. More actions need to be taken to decrease the prevalence of myopia, especially uncorrected myopia in children.

Pathologic myopia and severe pathologic myopia: correlation with axial length

PurposeThis study had three aims: (1) correlate axial length (AL), age and best-corrected visual acuity in high myopic patients scored on the ATN grading system; (2) determine AL cut-off values to distinguish between pathologic myopia (PM) and severe PM; and (3) identify clinical differences between PM and severe PM.MethodsThis is a cross-sectional, non-interventional study. All patients underwent complete ophthalmologic examination, ATN grading and multimodal imaging (colour fundus photography, swept-source OCT, fundus autofluorescence, OCT angiography and fluorescein angiography).ResultsSix hundred forty-four eyes from 345 high myopic patients were included. The eyes were graded on the ATN system and classified as PM (≥ A2) or severe PM (≥ A3, ≥ T3 and/or N2). Significant between-group (PM vs. severe PM) differences (p < 0.05) were observed on the individual ATN components (atrophic [A], tractional [T] and neovascular [N]), age, BCVA and AL. AL was also linearly correlated with the A, T and N components (r = 0.53, p < 0.01; r = 0.24, p < 0.01; r = 0.20, p < 0.01; respectively). ROC curve analysis showed the optimal AL cut-off value to distinguish between PM at 28 mm (AUC ROC curve: 0.813, specificity: 75%, sensitivity: 75%) and severe PM at 29.50 mm (AUC ROC curve: 0.760, specificity: 75%, sensitivity: 70%).ConclusionAL is the main variable associated with myopic maculopathy. Due to the clinical differences found between PM and severe PM, there is need to create an objective cut-off point to distinguish these two different entities being the optimal cut-off points for AL 28 mm and 29.5 mm, respectively. These objective AL cut-off values should be taken into account for determining a correct follow-up, ophthalmic management and treatment.

An ultra-rare case of 47,XXY/48,XXXY/49,XXXXY mosaic Klinefelter syndrome associated with diabetic ketosis and foot ulcer

Klinefelter syndrome (KS) is the most common chromosome aneuploidy and a common cause of infertility in males. KS patients have at least one extra X chromosome, and about 80% of patients have the karyotype 47,XXY. Twenty percent of KS patients have higher-grade aneuploidies (48,XXXY, 48,XXYY, 49,XXXXY) and exert some clinical manifestation different from those with 47,XXY. Here we report the case of a young man who initially presented with diabetic ketosis and foot ulcer and was later diagnosed as having an extremely rare mosaic variant of KS (47,XXY/48,XXXY/49,XXXXY). Clinical and laboratory features are summarized. The patient developed a severe foot ulcer with an 18-month history of diabetes. Learning disability was noted since early childhood. The patient had typical manifestations of KS, including increased height, sparse beard and body hair, and small penis. He also had some characteristic features of patients with additional sex chromosomes, including epicanthal folds, narrow palpebral fissures, prominent elbows, and undescended testicles. Severe myopia and myopic macular degeneration was also found. Lab tests revealed low testosterone and elevated FSH but normal LH levels. Chromosome analysis on lymphocytes revealed an aberration of 47,XXY/48,XXXY/49,XXXXY. This case provides information on KS patients with the extremely rare karyotype 47,XXY/48,XXXY/49,XXXXY, and also emphasizes the importance of considering KS in the differential diagnosis of a sterile male with diabetes.

The Association between Serum 25-hydroxyvitamin D Level and Myopia in Korean

Purpose : The purpose of this study was to investigate the relationship between serum 25 (OH) vitamin D level and myopia in Korean. Methods : Using data from the National Health and Nutrition Survey 2010, a total of 5,488 people aged 10 to 69 were targeted. Myopia was divided into subcategories as follows: mild myopia (-3.00<SE≤-0.50 D), moderate myopia (-6.00<SE≤-3.00 D), and high myopia (SE≤-6.00 D). Serum 25 (OH) vitamin D concentration was classified into two types as follows: deficiency (<20 ng/mL) and normal (≥20 ng/mL). Pearson's correlation analysis and covariate-corrected complex logistic regression were performed to evaluate the association between serum 25 (OH) vitamin D level and myopia. Results : Serum 25 (OH) vitamin D level and equivalent spherical refractive power showed a positive correlation (r=0.132, p<0.001). The risk factors for myopia were age, household income, education level, sun exposure, obesity, diabetes, hypertension, cataract, and family history of eye disease. When the serum 25 (OH) vitamin D level was less than 20 ng/mL, the risk of severe myopia increased by 2.55 times (95% confidence interval: 1.27~5.16) even after the risk factors were corrected. Conclusion : High myopia was associated with serum 25 (OH) vitamin D level in Korean.

Our Experience with Active Sentry and Centurion Ozil Handpieces

Aim: To compare parameters of phacoemulsification using handpiece Active Sentry and Centurion Ozil. Methods: We have evaluated results of 200 eyes of 129 patients that were operated for cataract at the Department of Ophthalmology. All surgeries were performed by one surgeon (NJ). In 100 eyes handpiece Active Sentry was used and in 100 eyes handpiece Centurion Ozil was used. The intraocular pressure during surgery (IOP), cumulative dissipated energy (CDE), ultrasound time (U/S time) and estimated consumption of balanced salt solution (BSS) were evaluated. Results: Using handpiece Ozil Centurion the IOP was 65 mmHg, use handpiece Active Sentry enabled decrease safely peroperative IOP to 46 mm Hg withouth increase of fluctuation or declension of stability of the anterior chamber. The mean CDE a U/S time were significantly statistically decreased using Active Sentry versus Centurion Ozil handpieces. Difference in estimated consumption of balanced salt solution was not statistically significant. Conclusion: Our results proved that using handpiece Active Sentry enabled statistically significantly decrease IOP during phacoemulsification and eliminated post-occlusion surge. This brings several advantages: more painless surgery for patients and more user-friendly procedure for surgeon especially in challenging cases (intraoperative floppy iris syndrome or severe myopia).

Corneal Biomechanical Properties in Varying Severities of Myopia.

Purpose: To investigate corneal biomechanical response parameters in varying degrees of myopia and their correlation with corneal geometrical parameters and axial length.Methods: In this prospective cross-sectional study, 172 eyes of 172 subjects, the severity degree of myopia was categorized into mild, moderate, severe, and extreme myopia. Cycloplegic refraction, corneal tomography using Pentacam HR, corneal biomechanical assessment using Corvis ST and Ocular Response Analyser (ORA), and ocular biometry using IOLMaster 700 were performed for all subjects. A general linear model was used to compare biomechanical parameters in various degrees of myopia, while central corneal thickness (CCT) and biomechanically corrected intraocular pressure (bIOP) were considered as covariates. Multiple linear regression was used to investigate the relationship between corneal biomechanical parameters with spherical equivalent (SE), axial length (AXL), bIOP, mean keratometry (Mean KR), and CCT.Results: Corneal biomechanical parameters assessed by Corvis ST that showed significant differences among the groups were second applanation length (AL2, p = 0.035), highest concavity radius (HCR, p < 0.001), deformation amplitude (DA, p < 0.001), peak distance (PD, p = 0.022), integrated inverse radius (IR, p < 0.001) and DA ratio (DAR, p = 0.004), while there were no significant differences in the means of pressure-derived parameters of ORA between groups. Multiple regression analysis showed all parameters of Corvis ST have significant relationships with level of myopia (SE, AXL, Mean KR), except AL1 and AL2. Significant biomechanical parameters showed progressive reduction in corneal stiffness with increasing myopia (either with greater negative SE or greater AXL), independent of IOP and CCT. Also, corneal hysteresis (CH) or ability to dissipate energy from the ORA decreased with increasing level of myopia.Conclusions: Dynamic corneal response assessed by Corvis ST shows evidence of biomechanical changes consistent with decreasing stiffness with increasing levels of myopia in multiple parameters. The strongest correlations were with highest concavity parameters where the sclera influence is maximal.

Effect of capsular tension ring implantation on capsular stability after phacoemulsification in patients with weak zonules: a randomized controlled trial. CTR implantation in cataract patients with weak zonules

BackgroundThe use of capsular tension ring (CTR) implantation to treat cataract patients with weak zonules is still controversial. The aim of this study was to examine the effects of CTR implantation on capsular stability after phacoemulsification in patients with weak zonules, especially patients who have undergone pars plana vitrectomy (PPV) or those who suffer from severe myopia.MethodsA total of 42 patients who underwent phacoemulsification and received an intraocular lens (IOL) were randomized to undergo CTR implantation or not. The control and CTR groups were compared in terms of uncorrected distant visual acuity (UDVA), best corrected distant visual acuity (BCDVA), refractive prediction error, the area of anterior capsulorhexis, and IOL inclination angle. Follow-up visits were conducted postoperatively at 1 day, 1 week, 1 month and 3 months. Subgroup analyses were performed based on PPV and severe myopia.ResultsSurgery significantly improved UDVA and BCDVA to similar extents in CTR and control patients, and refraction prediction error was similar between the two groups at all follow-up times. At 3 months after surgery, the area of anterior capsulorhexis was significantly larger in CTR patients than in controls (p = 0.0199). These differences were also significant between the subgroups of patients with severe myopia. Vertical IOL inclination was less within CTR groups at 3 months after surgery, especially in patients with severe myopia (p = 0.0286). At 1 week postoperatively, the proportion of individuals whose posterior lens capsule that had completely adhered to the posterior IOL surface was significantly higher among CTR patients (p = 0.023). No serious surgical complications were observed.ConclusionCTR implantation can benefit cataract patients with weak zonules by maintaining the shape of the capsular bag, reducing capsule shrinkage and stabilizing IOL inclination.Trial registrationChinese Clinical Trial Registry ChiCTR-INR-17011217, date of registration April 22, 2017, prospectively registered.

Effects of Orthokeratology on Axial Length Elongation in Anisometropes

Introduction: This study aimed to investigate the therapeutic effects of overnight orthokeratology (OK) lenses on anisometropes. Methods: We enrolled 178 anisometropes from August 2015 to August 2017. We then divided these patients into 2 parts depending on them wearing either monocular or binocular OK lenses. In part one, 47 monocular myopic subjects (25 males and 22 females) were treated with OK lenses in the myopic eyes only. We also labeled the myopic eyes as the OK group and the contralateral nonmyopic eyes as the control group. The initial average wearing age of the subjects was 12.35 ± 2.37 years (8–16 years). The mean follow-up duration was 15.43 ± 4.88 months (7–25 months). The average spherical equivalent refraction (SER) was −2.31 ± 1.16 diopter (D) in the OK group and 0.15 ± 0.49 D in the control group (p < 0.001). In part 2, 131 binocular myopic anisometropes (56 males and 75 females) were involved in the study. The eyes with more severe myopia were assigned to the G group and the contralateral eyes to the L group. The initial average wearing age of the subjects was 12.92 ± 2.60 years ( 8–16 years). The mean follow-up duration was 17.83 ± 5.02 months (7–26 months). The average SER was −4.79 ± 1.90 D in the G group and −3.14 ± 1.88 D in the L group (p < 0.001). We calculated the axial length (AL) difference and AL elongation as our primary outcome measures. Results: In part one, the AL elongation in the OK group (0.21 ± 0.09 mm) was significantly lower than that in the control group (0.70 ± 0.17 mm) at 24 months (p < 0.001). Meanwhile, the AL difference exhibited a decrease of 0.50 ± 0.29 mm from a baseline of 1.08 ± 0.35 to 0.58 ± 0.25 mm at 24 months (F = 24.539, p < 0.001). In part 2, the AL had increased by 0.17 ± 0.13 mm in the G group and 0.24 ± 0.18 mm in the L group after 24-month follow-up, respectively (p < 0.001). While the AL difference decreased from 0.55 ± 0.11 mm at the baseline, to 0.48 ± 0.08 mm at 24 months, eliciting a decrement in AL difference of 0.07 ± 0.09 mm (F = 3.884, p = 0.030). Conclusions: OK lenses can slow down AL growth in anisometropes and has a greater effect on reducing AL elongation in the more severely affected myopic eyes of anisometropic patients.