Myopic Refraction Research Articles

The Changes of KCNQ5 Expression and Potassium Microenvironment in the Retina of Myopic Guinea Pigs.

KCNQ5 is suggestively associated with myopia, but its specific role in the myopic process has not been studied further. The aim of this study was to investigate the expression of potassium channel gene KCNQ5 and the changes of K+ microenvironment within the retina of form deprivation myopia (FDM) guinea pigs. A total of 60 guinea pigs were randomly divided into the normal control (NC) group, the self-control (SC) group, and the form-deprivation (FD) group for different treatments. Molecular assays and immunohistochemistry (IHC) were conducted to measure the expression and distribution of KCNQ5-related gene and protein in the retina. We determined the K+ concentration in the retina. In addition, the possible effects of form deprivation on potassium ionic currents and the pharmacological sensitivity of KCNQ5 activator Retigabine and inhibitor XE991 to the M-current in RPE cells were investigated using the patch-clamp technique. As a result, FD eyes exhibited more myopic refraction and longer AL. The mRNA and protein levels of KCNQ5 significantly decreased in the FD eyes, but the K+ concentration increased. In addition, the M-type K+ current [IK(M)] density decreased in FD RPE cells, and were activated or inhibited in a concentration-dependent manner due to the addition of Retigabine or XE991. Overall, KCNQ5 was significantly downregulated in the retina of FD guinea pigs, which may be associated with the increasing K+ concentration, decreasing IK(M) density, and elongating ocular axis. It suggested that KCNQ5 may play a role in the process of myopia, and the intervention of potassium channels may contribute to the prevention and control of myopia.

Melanopsin modulates refractive development and myopia

Myopia, or nearsightedness, is the most common form of refractive abnormality and is characterized by excessive ocular elongation in relation to ocular power. Retinal neurotransmitter signaling, including dopamine, is implicated in myopic ocular growth, but the visual pathways that initiate and sustain myopia remain unclear. Melanopsin-expressing retinal ganglion cells (mRGCs), which detect light, are important for visual function, and have connections with retinal dopamine cells. Here, we investigated how mRGCs influence normal and myopic refractive development using two mutant mouse models: Opn4−/− mice that lack functional melanopsin photopigments and intrinsic mRGC responses but still receive other photoreceptor-mediated input to these cells; and Opn4DTA/DTA mice that lack intrinsic and photoreceptor-mediated mRGC responses due to mRGC cell death. In mice with intact vision or form-deprivation, we measured refractive error, ocular properties including axial length and corneal curvature, and the levels of retinal dopamine and its primary metabolite, L-3,4-dihydroxyphenylalanine (DOPAC). Myopia was measured as a myopic shift, or the difference in refractive error between the form-deprived and contralateral eyes. We found that Opn4−/− mice had altered normal refractive development compared to Opn4+/+ wildtype mice, starting ∼4D more myopic but developing ∼2D greater hyperopia by 16 weeks of age. Consistent with hyperopia at older ages, 16 week-old Opn4−/− mice also had shorter eyes compared to Opn4+/+ mice (3.34 vs 3.42 mm). Opn4DTA/DTA mice, however, were more hyperopic than both Opn4+/+ and Opn4−/− mice across development ending with even shorter axial lengths. Despite these differences, both Opn4−/− and Opn4DTA/DTA mice had ∼2D greater myopic shifts in response to form-deprivation compared to Opn4+/+ mice. Furthermore, when vision was intact, dopamine and DOPAC levels were similar between Opn4−/− and Opn4+/+ mice, but higher in Opn4DTA/DTA mice, which differed with age. However, form-deprivation reduced retinal dopamine and DOAPC by ∼20% in Opn4−/− compared to Opn4+/+ mice but did not affect retinal dopamine and DOPAC in Opn4DTA/DTA mice. Lastly, systemically treating Opn4−/− mice with the dopamine precursor L-DOPA reduced their form-deprivation myopia by half compared to non-treated mice. Collectively our findings show that disruption of retinal melanopsin signaling alters the rate and magnitude of normal refractive development, yields greater susceptibility to form-deprivation myopia, and changes dopamine signaling. Our results suggest that mRGCs participate in the eye's response to myopigenic stimuli, acting partly through dopaminergic mechanisms, and provide a potential therapeutic target underling myopia progression. We conclude that proper mRGC function is necessary for correct refractive development and protection from myopia progression.

An evaluation of the IOLMaster 700 and its agreement with the IOLMaster v3 in children.

To evaluate the repeatability and reproducibility of the swept-source optical coherence tomographer Zeiss IOLMaster 700 and compare its outputs with those obtained using partial coherence interferometry (Zeiss IOLMaster v3) in a healthy, paediatric population. This is a cross-sectional, observational study. Examiner 1 took two sets of biometric measurements (axial length [AL],mean corneal radius of curvature [Kmean ], anterior chamber depth [ACD] and lens thickness [LT]) using the IOLMaster 700, and one set of measurements (AL, Kmean and ACD) using the IOLMaster v3. Examiner 2 took one full set of measurements using the IOLMaster 700. Mean differences and 95% limits of agreement (LOA) were calculated, and Bland and Altman plots used to explore repeatability and reproducibility of the IOLMaster 700 alongside establishing its agreement with the IOLMaster v3. Mean participant age was 7.52±0.58years. Repeatability analyses demonstrated small mean differences and narrow 95% LOA for AL (0.001, -0.013 to 0.015mm),Kmean (0.002, -0.020 to 0.024mm),ACD (-0.003, -0.031 to 0.024mm)and LT (0.001, -0.024 to 0.026mm), respectively. Similarly, small mean differences and narrow 95% LOA established excellent reproducibility (AL 0.001, -0.016 to 0.018mm; Kmean -0.001, -0.027 to 0.025mm; ACD -0.010, -0.041 to 0.021mm; LT 0.002, -0.016 to 0.020mm). The IOLMaster 700 and IOLMaster v3 demonstrated good agreement with small mean differences and narrow 95% LOA (AL 0.009, -0.034 to 0.052mm; Kmean 0.016, -0.013 to 0.044mm;ACD 0.134, 0.055 to 0.212mm). When used within a paediatric population, these data demonstratethe IOLMaster 700 to be highly repeatable and reproducible for measures of AL, Kmean , ACD and LT. There is excellent inter-instrument agreement between the IOLMaster 700 and IOLMaster v3 for measures of AL and Kmean . ACD measurementsshowweaker agreement. These data will be useful when considering reports from population-based studies of refractive error and clinical myopia research.

Анализ изменения биомеханических свойств роговицы на приборе CORVIS ST (Oculus, Германия) у пациентов с миопией и миопическим астигматизмом после операции ФРК

Purpose. To analyze changes in corneal biomechanical properties after refractive surgery of photorefractive keratectomy (PRK) in patients with myopia and myopic astigmatism. Material and methods. The study included 10 patients (20 eyes) aged 23 to 51 years, planned for keratorefractive surgery for myopia and myopic astigmatism. Spheroequivalent of myopic refraction was -2.5 to -9.25 diopters, corneal astigmatism: -0.5 to 4.25 diopters. Patients underwent keratotopography using Pentacam scanning projection topograph (Oculus, Germany) and study of cornea biomechanical properties using Corvis ST non-contact tonometer (Oculus, Germany) at baseline and 1 month after surgery using the PRK technique. Results. Initially, in 3 patients (30%), keratotopogram showed elevation along posterior corneal surface (up to +26) and increase in corneal curvature in lower sections. Tomographic Biomechanical Index in all 10 patients ranged from 0.01 to 0.46, with 3 of them exceeding 0.3. Central Corneal Thickness in all patients averaged 514 ± 31 µm, of which 7 patients (70%) had 500 µm or less. Month after surgery only two indicators revealed statistically significant difference: Inverse Concave Radius (on average 5.95 ± 0.79 mm before surgery and 7.02 ± 0.70 mm after) and the Central Corneal Thickness (514 ± 31 µm before surgery and 410 ± 41 µm after). Conclusion. When selecting patients for keratorefractive surgery, it is imperative to take into account the initial corneal biomechanical properties to select the optimal technique in each specific case. Key words: corneal biomechanical properties, photorefractive keratectomy, myopia, myopic astigmatism.

Транс-ФРК: Компромисс?

Purpose. A statement of the fact of the presence of abnormally high visual acuity after the first stage of Trans-PRK and a proposal to use this information when planning laser correction of high and ultra-high myopia. Material and methods. Eyes were selected after the first stage of Trans-PRK (581 eyes), in which the postoperative myopic sphere equivalent was at least 2 diopters. Visual acuity was compared with non-operated eyes with a similar myopic sphere equivalent. Results. The revealed effect is that patients with high residual myopic refraction after the first stage of Trans-PRK have significantly higher visual acuity than non-operated people with similar refraction. Postoperative keratotopograms do not give grounds for understanding this effect. Conclusion. The explanation can be the forced work of the visual analyzer of the brain. With this in mind, it is possible to achieve and widely use a compromise between the desired and possible result in the practice of laser correction of myopia. Key words: myopia correction, first-stage, Trans-PRK, residual myopia, sphere equivalent, sight acuity, keratotopogram, visual analyzer of the brain, Ambliocor.

Simultaneous Myopic Defocus for Myopia Control: Effect on Accommodation, Peripheral Refraction and Retinal Image Quality in Non-Presbyopic Patients

Exposing the retina to a simultaneous myopic defocus is an optical method that has shown a promising effect in slowing the progression of myopia. Optical treatments applying a simultaneous defocus are available in the form of soft contact lenses or multifocal lenses originally designed to correct presbyopia. Orthokeratology is another optical method that slows down the progression of myopia. With orthokeratology, it is hypothesized that a change in peripheral refraction could slow the progression of myopia. We aimed to measure the accommodation response between monofocal and multifocal contact lenses in young subjects. Additionally, we performed a ray-tracing simulation to visualize the quality of the retinal image and the refractive status in the retinal periphery. The accommodation and pupil size measurements were performed on 29 participants aged 24.03 ± 2.73 years with a refractive error (spherical equivalent) of −1.78 ± 1.06 D. With the multifocal lens in situ, our participants showed less accommodation in comparison to the monofocal contact lens (mean difference, 0.576 ± 0.36 D, p > 0.001) when focusing on a near target at 40 cm. Pupil size became smaller in both contact lens groups during an accommodation of 0.29 ± 0.69 mm, p ≤ 0.001 and 0.39 ± 0.46 mm, p ≤ 0.001 for monofocal and multifocal contact lenses, respectively. The ray-tracing model showed a degradation for central and peripheral vision with the multifocal contact lens. The peripheral refraction was relatively myopic in both contact lens conditions up to 30°. Even if the accommodation ability is without fault, parts of simultaneous myopic defocus are used for the near task. The peripheral refraction in the ray-tracing model was not different between the two contact lenses. This is contrary to the proposed hypothesis that myopic peripheral refraction slows down the progression of myopia in current optical methods.

Declines in PDE4B activity promote myopia progression through downregulation of scleral collagen expression

Myopia is the most common cause of a visual refractive error worldwide. Cyclic adenosine monophosphate (cAMP)-linked signaling pathways contribute to the regulation of myopia development, and increases in cAMP accumulation promote myopia progression. To pinpoint the underlying mechanisms by which cAMP modulates myopia progression, we performed scleral transcriptome sequencing analysis in form-deprived mice, a well-established model of myopia development. Form deprivation significantly inhibited the expression levels of genes in the cAMP catabolic pathway. Quantitative real-time polymerase chain reaction analysis validated that the gene expression level of phosphodiesterase 4B (PDE4B), a cAMP hydrolase, was downregulated in form-deprived mouse eyes. Under visually unobstructed conditions, loss of PDE4B function in Pde4b-knockout mice increased the myopic shift in refraction, −3.661 ± 1.071 diopters, more than that in the Pde4b-wildtype littermates (P < 0.05). This suggests that downregulation and inhibition of PDE4B gives rise to myopia. In guinea pigs, subconjunctival injection of rolipram, a selective inhibitor of PDE4, led to myopia in normal eyes, and it also enhanced form-deprivation myopia (FDM). Subconjunctival injection of dibutyryl-cyclic adenosine monophosphate, a cAMP analog, induced only a myopic shift in the normal visually unobstructed eyes, but it did not enhance FDM. As myopia developed, axial elongation occurred during scleral remodeling that was correlated with changes in collagen fibril thickness and distribution. The median collagen fibril diameter in the FDM + rolipram group, 55.09 ± 1.83 nm, was thinner than in the FDM + vehicle group, 59.33 ± 2.06 nm (P = 0.011). Thus, inhibition of PDE4 activity with rolipram thinned the collagen fibril diameter relative to the vehicle treatment in form-deprived eyes. Rolipram also inhibited increases in collagen synthesis induced by TGF-β2 in cultured human scleral fibroblasts. The current results further support a role for PDE enzymes such as PDE4B in the regulation of normal refractive development and myopia because either loss or inhibition of PDE4B function increased myopia and FDM development through declines in the scleral collagen fibril diameter.

Comment on: Risk factors for posterior capsule rupture in cataract surgery as reflected in the European Registry of Quality outcomes for cataract and refractive surgery

We read with interest the article by Segers et al. where they analyzed the data from a very large sample (more than 2 800 000 cases) obtained from the European Registry of Quality Outcomes (EUREQUO).1 The authors identified several risk factors associated with posterior capsule rupture, including hyperopic target refraction in the biometry. When comparing the eyes targeted for postoperative emmetropia (−0.50 to +0.50 diopters [D]), selecting a myopic target refraction <−1.50 D, turned out to be a protective factor (odds ratio [OR] 0.74, 95% CI 0.69-0.79, P < .001), whereas selecting a hyperopic target refraction (>0.50 D) was identified as a risk factor for posterior capsule rupture, and the higher the hyperopic target refraction, the greater the risk. For mild hyperopic target refraction, that is +0.51 to +1.50 D, multivariate logistic regression model showed OR 1.24, 95% CI 1.08-1.43, P < .001, and for higher hyperopic target refraction, that is >+1.50 D, the results showed OR 1.37, 95% CI 1.13-1.65, P < .001. Unfortunately, this information about the target refraction selected by the surgeon when calculating the power of the intraocular lens to be implanted cannot be directly related to anatomical characteristics of the eyeball, and therefore, the conclusions reached are based on assumptions that are not always correct. For example, within the group of eyes with a myopic target refraction <−1.50 D, there could be eyes with any axial length and any previous refractive error, because it could simply be due to the surgeon trying to leave the patient with a monovision. Something similar happens with hyperopic target refraction, because, for example, if a high myopic had a refractive surprise in the first eye, the surgeon could have selected hyperopic target refraction for the second eye to avoid anisometropia, and this does not mean that it was a short eye. This weakness makes it very difficult to reach reliable conclusions about this parameter of the target refraction. On the other hand, some parameters that can be very useful, and that are determined in all eyes undergoing cataract surgery, are the biometric data: the axial length and the depth of the anterior chamber. The various devices available to perform these measurements have shown considerable similarity in their results.2 This information would allow to reach much more reliable conclusions regarding risk factors for posterior capsule rupture. It would be an interesting alternative to evaluate the possibility of including them within the EUREQUO form. Finally, according to Table 2 the parameter “Other comorbidity” was also significantly associated with posterior capsule rupture, and indeed, it was the second highest OR value obtained, surpassed only by corneal opacities (OR 3.03, 95% CI 2.91-3.16, P < .001). It is crucial, then, to define which comorbidities were included in this item. In order that this information is more specific, it would be justified consider modifying that question in the form, requiring that if the surgeon answers other, the comorbidity must be described.

Sunlight Exposure: A Protective Role in the Development of Myopia

The study objective was to assess the correlation of time outdoors in sunlight hours with spherical equivalent refraction (SER) and other variables. This was a cross-sectional study carried out in the Fauji Foundation Hospital, Rawalpindi, between January and April 2019. A total of 110 Individuals were included via convenient sampling, with myopia defined as having at least -0.5 D (SER ≤ -0.5 D). Collection of Questionnaires with interviews regarding eye care behaviour along with auto-refraction was done, followed by calculation of spherical equivalent refraction. Those having high myopia of 6 D or more (SER ≤ - 6 D), hyperopia of 0.5 D or more (SER ≥ +0.5 D), and history significant for ocular trauma and surgeries, were excluded. After data cleaning and their entry, analyses were done using SPSS version 26. The mean age data, available for 105 individuals, was 15.4 ± 3.69 years. Spearman's correlation was used for right SER with time outdoors in summers (r= +0.25, p=0.008) and winters (r= +0.243, p=0.010), indicating an inverse relationship with myopia. Females had more myopic refraction than males, but the independent sample t-test was not significant. Logistic regression was used and a protective effect was found for both summer and winter time outdoors, while education level was associated with myopia. Key Words: Myopia, Spherical equivalent refraction (SER), Sunlight exposure.

Implications of the Relationship Between Refractive Error and Biometry in the Pathogenesis of Primary Angle Closure.

PurposeThe purpose of this study was to investigate the relationship between refractive error and ocular biometry and its implication in the pathogenesis of primary angle closure (PAC).MethodsWe have retrospectively recruited 119 PAC eyes and 388 non-PAC eyes with an axial length (AL) of ≤25.0 mm and a spherical equivalent (SE) of ≥−6.0 diopters (D). Stepwise multiple regression was performed for keratometry value (K), AL, anterior chamber depth (ACD), and SE.ResultsPAC eyes were more likely to be in women and have a higher IOP and shorter AL than non-PAC eyes. In a multiple regression analysis, SE was not associated with PAC. The associations between AL and SE or AL and ACD were not different in PAC eyes compared with non-PAC eyes. However, the cornea was flatter in PAC eyes (β = −0.448, P < 0.001), and a flatter cornea was associated with more hyperopic refraction (β = −0.454, P < 0.001) and shallower ACD (β = 0.073, P < 0.001) in PAC eyes. ACD was not associated with SE in non-PAC eyes, but shallower ACD was associated with greater myopic refraction in PAC eyes (β = 1.117, P = 0.006).ConclusionsPAC eyes seem to have flatter cornea compared with non-PAC eyes. A shallower ACD seems to be associated with greater myopic refraction in PAC eyes, but not in non-PAC eyes.

New Polygenic Risk Score to Predict High Myopia in Singapore Chinese Children.

PurposeThe purpose of this study was to develop an Asian polygenic risk score (PRS) to predict high myopia (HM) in Chinese children in the Singapore Cohort of Risk factors for Myopia (SCORM) cohort.MethodsWe included children followed from 6 to 11 years old until teenage years (12–18 years old). Cycloplegic autorefraction, ultrasound biometry, Illumina HumanHap 550, or 550 Duo Beadarrays, demographics, and environmental factors data were obtained. The PRS was generated from the Consortium for Refractive Error and Myopia genomewide association study (n = 542,934) and the Strabismus, Amblyopia, and Refractive Error in Singapore children Study (n = 500). The Growing Up in Singapore Towards healthy Outcomes Cohort study (n = 339) was the replication cohort. The outcome was teenage HM (≤ −5.00 D) with predictive performance assessed using the area under the curve (AUC).ResultsMean baseline age ± SD was 7.85 ± 0.84 (n = 1004) and 571 attended the teenage visit; 23.3% had HM. In multivariate analysis, the PRS was associated with a myopic spherical equivalent with an incremental R2 of 0.041 (95% confidence interval [CI] = 0.010, 0.073; P < 0.001). AUC for HM (0.77 [95% CI = 0.71–0.83]) performed better (P = 0.02) with the PRS compared with a model without (0.72 [95% CI = 0.65, 0.78]). Children at the top 25% PRS risk had a 2.34-fold-greater risk of HM (95% CI = 1.53, 3.55; P < 0.001).ConclusionsThe new Asian PRS improved the predictive performance to detect children at risk of HM.Translational RelevanceClinicians may use the PRS with other predictive factors to identify high risk children and guide interventions to reduce the risk of HM later in life.

Выбор оптимального способа предоперационной оценки риска развития синдрома «сухого глаза» у пациентов с миопией

Aim. Comparative analysis of the effectiveness of keratotopography methods and classical Norn’s test in assessing the stability of the tear film (TF) in patients with myopia before photorefractive surgery. Methods. The study involved 26 patients. All of them were planned for keratorefractive surgery to correct myopic refraction and astigmatism. Their age averaged 32.5±14.5 years (18-47 years). The stability of pre-corneal tear film was assessed using computed keratotopography and Norn’s test - the tear film rupture time (TFRT) was determined. A standard questionnaire was also used to assess the severity of symptoms of dry eye syndrome (DES). A comparison was made of the indicators of tear film, stability obtained by the methods of keratotopography and Norn’s test, with their subsequent comparison with the data of the questionnaire. Results. In 17 patients (65.4 %), TFRT index corresponded to the age norm. In the remaining 9 people (34.6 %), indicators of tear film stability were reduced both by keratotopography (12±4 sec) and by Norn’s test (13.5± 4.5 sec), and there were also subjective signs of dry eye syndrome according to questionnaire data. The data turned out to be comparable. Conclusion. The incidence of impaired stability of the TF and subjective manifestations of DES among patients planned for keratorefractive surgery for myopia and myopic astigmatism was significant and, according to our data, made 34.6 %. To prevent complicated postoperative course of photorefractive surgery, it is necessary to assess the condition of the ocular surface immediately before refractive surgery, to identify the risk group for DES development. Key words: dry eye syndrome; tear film; keratotopography; Norn’s test; tear film rupture time.

Our Experience of Using Soft Bifocal Contact Lenses in Children with Progressive Myopia

Introduction. According to the studies, one out of three myopic patients with refraction greater than –6.00 D and an axial length greater than 26 mm is at high risk of facing low vision and loss of sight in the future. According to the results of medical examinations and screenings in carried out in Ivanovo, the prevalence of myopia in primary school children has increased three times during the past twenty years. Myopic children under 7 years old are six times more likely to have myopia progressed to higher degrees than children in which myopia onset took place later (at the age of 11–12 years). Optical interventions for myopia control such as orthokeratology and soft bifocal contact lenses have a strong body of evidence and are well accepted by ophthalmologists.Purpose. The purpose of the present study was to investigate the effect of soft bifocal contact lenses on refraction, accommodation and axial length in children with progressive myopia.Materials and methods. We observed 30 children aged 8–15 years with myopia progression rate of 0.82 D/year and accommodative weakness and instability. We prescribed OKVision PrimaBio Bi-focal design soft bifocal contact lenses (OKVision, Russia) that feature +4.00 D addition power on periphery. The effectiveness was estimated by monitoring refraction, accommodation and axial length every three months within a year.Results. After 12 months of wearing soft bifocal contact lenses, the annual myopia progression rate decreased 4.3 times on average. We were able to stabilize myopia in 50% of the children during the period of monitoring. The use of this intervention had a strong effect on accommodation resulting in an increase of its amplitude and reserve.Conclusion. The use of soft bifocal contact lenses has been proven to have a strong inhibitory effect on myopia progression rate. Myopia stabilization manifested itself as the absence of increase in myopic refraction and axial length as well as normalization of accommodative function.

Early Age of the First Myopic Spectacle Prescription, as an Indicator of Early Onset of Myopia, Is a Risk Factor for High Myopia in Adulthood.

Purpose The present study investigated the risk factors for high myopia in adulthood, with a focus on the age at which children wore their first spectacles. Methods Adults aged between 20 and 45 years were invited to complete a questionnaire about age, sex, current refractive error, high myopia in parents, early onset of myopia presented by the age of the first myopic spectacle prescription, refractive power of the first spectacles, and life habits at different educational stages. The associations between these factors and high myopia in adulthood were then evaluated and analyzed. Results In total, 331 participants were enrolled. Their average refractive error was −4.03 diopters, and high myopia was noted in 27.5% of the study participants. Only 3.3% of participants had fathers with high myopia, while 6.0% had mothers with high myopia. The participants received their first myopic spectacle prescription at a mean age of 13.35 years, with a mean refractive error of −1.63 diopters. The significant risk factors for developing high myopia in adult life were earlier age of the first spectacles prescribed (p < 0.001), higher refractive power of the first spectacles (p < 0.001), mother with high myopia (p=0.015), and after-school class attendance in senior high school (p=0.018). Those who wore their first spectacles at <9 years of age were more predisposed to high myopia than those who did so at ≧13 years, with an odds ratio of 24.9. Conclusion The present study shows that earlier onset of myopia, which is presented by the age of the first myopic spectacle prescription, higher myopic refraction of the first spectacles, mothers with high myopia, and after-school class attendance in senior high school are risk factors for high myopia in adulthood. It suggests that delaying the onset of myopia in children is important for the prevention of high myopia in later life.

Анализ кератотопографических и биомеханических показателей роговицы c оценкой влияния результатов диагностики на тактику ведения пациента с миопической рефракцией

Purpose. To analyse keratopographic and biomechanical corneal indicators with the diagnostic results assessment of the influence on the treatment tactics of myopic refraction patient. Materials and methods. Keratotopographic and biomechanical parameters of the cornea in a patient with mild myopia were evaluated. Results. The Belin/Ambrosio (Enchanced Ectasia Display) - BAD keratoconus screening program was used on Pentacam HR, which did not reveal corneal pathology. According to the results of CBI (Corvis biomechanical index) on Corvis ST (OD - 0.61, OS - 0.48), that was indicating poor corneal biomechanical properties and a high risk of keratectasia development. Conclusion. Ophthalmic examination, using The Corvis ST (Oculus, Germany) biomechanical measurements, makes possible to reveal with greater sensitivity subclinical signs of a keratectatic process at the pre-clinical stage of development. Key words: keratotopography, corneal biomechanics, keratoconus.

Исходы самопроизвольного регресса ретинопатии недоношенных

Purpose. To analyze postnatal outcomes in children with spontaneous ROP regression. Material and methods. The study included 37 children (74 eyes) with spontaneous ROP regression. Gestational age was ranged from 23 to 32 weeks, body weight - from 493 to 1660 g at birth. Depending on the observation period, the children were divided into 2 age groups: 1 - from 1 month to 4 years old - 31 children (62 eyes), 2 - from 9 to 13 years old - 6 children (12 eyes). The diagnostics included standard ophthalmological examinations and additional methods. Results. In the first group, upon reaching the age of 1-year, complete retinal vascularization was observed in 26 (83%) cases (52 eyes). 5 children (10 eyes) had a narrow retinal avascular zone in the temporal segment. In the second group, in cases of postponed 3-rd stage of ROP, more severe disorders in the peripheral parts of the retina were revealed: compaction of the posterior hyaloid membrane with fixation and zones of traction retinoschisis of varying length. In the first years of life, all patients with ROP had a history of predominantly hyperopic refraction (94%). However, myopic refraction prevailed (82%) in the second group of children reaching school age. Conclusion. Considering the significant variability of the clinical manifestations of the cicatricial stage of ROP with spontaneous regression, long-term observation and a comprehensive ophthalmological examination of this group of patients are necessary for timely treatment. Key words: retinopathy of prematurity, spontaneous regression, cicatricial phase.

Частота, структура, основные причины и исходы кератитов, спровоцированных ношением контактных линз

Purpose. To study the frequency, structure and outcomes of keratitis caused by wearing contact lenses. Material and methods. A continuous sample of all cases of the incidence of keratitis provoked by an error in wearing contact lenses in adult patients from 2017 to 2019 was carried out. All of them underwent inpatient treatment for this matter in the ophthalmological department of the City Clinical Hospital No. 10 of the Ministry of Health of the Khabarovsk Territory. The provoking factors, etiological structure, the frequency of restoration of visual functions and the outcomes of these keratitis were determined. Results. The total number of cases studied was 51 (52 eyes). Keratitis was provoked by wearing soft contact lenses (SCL) mainly in females (76.5%) aged 20– 30 years. Lenses were selected mainly for moderate myopia (44%). Bacterial etiology of keratitis was detected in 61% of cases, mixed – in 31% of cases, viral – in 8%. The main reason for the development of keratitis is violations in the mode of using SCL (sleep in lenses, prolonged use of SCL with an expired wearing period, violation of the rules for caring for lenses). Conclusion. In the structure of keratitis, provoked by wearing SCL, there were mainly bacterial keratitis (61%). The predominant factors contributing to the formation of keratitis were: sleeping in lenses (51%) and prolonged wearing of lenses exceeding their useful life (24%). The treatment made it possible to completely restore visual functions in 38% of patients. Key words: keratitis, soft contact lenses, myopic refraction.

Clinical differences between toric intraocular lens (IOL) and monofocal intraocular lens (IOL) implantation when myopia is determined as target refraction

BackgroundThe aim of this study is to analyze and compare the clinical results of toric intraocular lens (IOL) and monofocal IOL implantation when the target refraction value is -3 diopter (D) in cataract patients with corneal astigmatism > 1.5 diopters (D).Methods We performed a retrospective chart review for patients with corneal astigmatism > 1.5D who underwent cataract surgery and their target refraction is -3D. 100 eyes (100 patients; monofocal IOL, 60; toric IOL, 40) were enrolled in the current study. Near and distant uncorrected visual acuity (UCVA), corrected VA, spherical equivalent and refractive, corneal astigmatism were evaluated before and after surgery.ResultsThe near UCVA of the toric IOL group (0.26 ± 0.33) after cataract surgery was significantly better than that of the monofocal IOL group (0.48 ± 0.32) (p = 0.030). The distant UCVA of the toric IOL group (0.38 ± 0.14) was also significantly better than that of the monofocal IOL group (0.55 ± 0.22) (p = 0.026). Best-corrected visual acuity (p = 0.710) and mean spherical equivalent (p = 0.465) did not show significant differences between the toric IOL group and the monofocal IOL group. In the toric IOL group, postoperative refractive astigmatism was − 0.80 ± 0.46D and postoperative corneal astigmatism was − 1.50 ± 0.62D, whereas the corresponding values in the monofocal IOL group were − 1.65 ± 0.77D and − 1.45 ± 0.64D; residual refractive astigmatism was significantly lower with toric IOL implantation compared with monofocal IOL implantation (p = 0.001). There were no postoperative complications.ConclusionsWhen myopic refraction such as -3D was determined as the target power in patients with corneal astigmatism, toric IOL implantation led to excellent improvement in both near and distant UCVA.

Nutritional Factors and Myopia: An Analysis of National Health and Nutrition Examination Survey Data.

The rise in the prevalence of myopia, a significant worldwide public health concern, has been too rapid to be explained by genetic factors alone and thus suggests environmental influences. Relatively little attention has been paid to the possible role of nutrition in myopia. The availability of the large National Health and Nutrition Examination Survey data set, which includes results from vision examinations, offers the opportunity to investigate the relationship between several nutrition-related factors, including body metrics, and the presence and magnitude of myopia. Cross-sectional survey data sets with vision examination, demographic, body metrics, and nutritional data, collected as part of the National Health and Nutrition Examination Survey over the years of 2003 to 2008, were extracted for analysis. Based on already published basic and epidemiological studies, the following parameters were selected for study: body height and body mass index, demographics, serum vitamin D and glucose/insulin levels, and caffeine intake, using multivariable models and objectively measured refractive errors as the main outcome measure. Data from a total of 6855 ethnically diverse Americans aged 12 to 25 years were analyzed. In final multivariate models, female sex and age were the most significant factors related to myopia status and refractive error. In general, body metrics (body mass index) or nutritional factors (serum vitamin D, glucose levels, and caffeine intake) were found to be associated with refractive error or myopia status; however, increased insulin levels were related to increased odds of having myopia. These largely negative findings suggest that other environmental factors, such as those related to the visual environment, may contribute more to the development and/or progression of myopia and would argue for continued research in these areas in support of more evidence-based myopia clinical management.

Myopia and glaucoma progression among patients with juvenile onset open angle glaucoma: A retrospective follow up study.

To identify the risk factors for glaucoma progression, especially the association with myopia, among treated juvenile open angle glaucoma (JOAG) patients. Glaucomatous progression was analysed in the eyes of JOAG patients with at least 5-years of follow up in this retrospective study. Baseline variables such as age, inheritance pattern, baseline intraocular pressure (IOP), baseline central corneal thickness, visual acuity, baseline refractive error, spherical equivalent (SE) and duration of follow-up were noted. Stereoparametric global trend analysis and Moorfields Regression Analysis on confocal scanning laser ophthalmoscopy were used to detect progression. Variables associated with glaucoma progression, with respect to progressors (PG) and non-progressors (NPG) were analysed. Since both eyes of a patient were taken for analysis, a generalised estimating equation method was used to correct the bias. Among 74 eyes (37 subjects), glaucoma progression was noted in 11 eyes (14.9%) of 8 patients, with a median time to progression of 7.4years (range 5-15.5years). For myopes (SE≤-1.00D), glaucoma progression was 18 times more likely than mild and no myopes (>-1DS) (p=0.03, 95% CI: 1.14, 217.44). The prevalence of myopia in the JOAG, PG and NPG cohorts was 70.3%, 87.5%, and 65.5%, respectively. Myopia progression was noted at follow up in 70% patients. One-unit increase in baseline vertical cup disc ratio, 1mmHg increase in IOP fluctuations and 1dB year-1 depression of visual field were associated with 0.44, 0.06 and 0.07D year-1 increases in the rate of myopia progression, respectively. JOAG progressors had a greater baseline myopic refraction and a faster myopia development over time. The development of myopia in JOAG eyes could be an indicator of glaucoma progression, and hence progressing myopic (≤-1D) JOAG patients should be followed up more rigorously.