Rate Of Axial Growth Research Articles

Comparison of the axial growth with multifocal and monofocal intraocular lenses in unilateral pediatric cataract surgery.

To compare axial growth in pediatric cataract patients who underwent multifocal intraocular lens (IOL) implantation without anterior vitrectomy (AV) with that in pediatric patients who underwent monofocal IOL implantation with or without AV. Patients who had unilateral pediatric cataracts and underwent surgery at 3-6years of age from June 6, 2019, to June 30, 2020, at our institution were prospectively analyzed. The patients were categorized into Group A: multifocal IOL implantation with optic capture in Berger's space without AV; Group B: monofocal IOL implantation with optic capture in Berger's space without AV; and Group C: bag-in-the-lens monofocal IOL implantation with AV. Groups A', B' and C' consisted of the fellow eyes from the respective groups. Axial growth and monthly growth rates were compared among the 3 treatment groups, as well as between the treated eyes and the fellow eyes. Thirty-one, 23, and 14 children fulfilling the inclusion criteria, respectively, were included in the final analysis. There were no significant differences in patient age at the time of surgery or preoperative axial length (P > 0.05). After a mean follow-up of 35.57 ± 3.78months, significant differences in the axial growth and the monthly growth rate were observed (P < 0.05), and Group A had the least axial elongation. Comparing treated eyes with fellow eyes, the amount and rate of axial growth were lower in Group A than in Group A' (P < 0.05), no significant differences were found in Group B (P > 0.05), and Group C had greater growth than did Group C' (P < 0.05). The implanting multifocal intraocular lenses and maintenance of vitreous body integrity may be protective factors against excessive axial growth in pediatric cataract patients. Clinical trial registration (prospective study): chiCRT1900023155; 2019-05-14.

Genotype Impacts Axial Length Growth in Pseudophakic Eyes of Marfan Syndrome.

The purpose of this study was to investigate the relationship between axial length (AL) growth and FBN1 genotype in patients with Marfan syndrome (MFS) after lens surgery and customize the selection of intraocular lens (IOL) power. Patients with MFS who had lens surgery and primary IOL implantation received panel-based next-generation sequencing (NGS). The rate of axial length growth (RALG) was calculated using pre- and postoperative AL measurements and corrected log10-transformed age. A multivariable regression model of RALG was developed after analyzing the effect of FBN1 genotypes and confounding factors. A total of 139 probands of MFS with a median age at lens surgery of 6.25 years (interquartile range [IQR] = 4.67, 12.50 years) were followed up for a median duration of 2.08 years (IQR = 1.16, 3.00 years). The AL growth curve between the age of 3 and 15 years old was logarithmic. Dominant-negative (DN) variants affecting the disulfide-bridge forming cysteines and the conserved residues for calcium-binding had significantly higher RALG than DN variants affecting other structures (P = 0.001) but comparable to that of haplo-insufficiency variants (P = 1.000). Pre-operative AL (b = 0.563, P = 0.011) and genotype constant (b = 2.603, P = 0.011) were significantly associated with RALG in the final model. A Python-based calculator, Marfan IOL Calculator version 2.0, was programmed using the RALG to predict postoperative AL and customize IOL selection based on the ocular biometric parameters and FBN1 genotype. FBN1 genotype impacted the growth of AL in patients with MFS after IOL implantation. Knowing the FBN1 genotype could help cataract surgeons to customize IOL selection.

Multiple segment spectacle lenses for myopia control. Part 2: Impact on myopia progression.

Initial studies have suggested that multiple segment (MS) spectacle lenses can reduce the progression rate of childhood myopia and axial eye growth. This paper aimed to compare the effectiveness of two different available designs of MS lens and to explore the nature of their control effect. Published data from the only two clinical trials in which changes in mean spherical equivalent refraction (SER) and axial length (AL) for matched groups of myopic children wearing either MS or single-vision (SV) spectacle corrections, recorded over a period of at least 2 years, were further analysed and compared. Both trials involved Chinese children of similar ages and visual characteristics, but the trials were located in different cities. The two MS lenses examined were MiyoSmart or DIMS (Hoya) and Stellest (Essilor). Absolute changes in SER and AL differed over time during the two trials. However, if the results were expressed in terms of efficacy over successive 6-month periods, then the two MS lenses produced broadly similar results (initial efficacy for the control of myopia progression of about 60%-80%, declining over 2 years to about 35%-55%). Control appears to be absolute rather than proportional. Myopia control may be due to either the additional myopic defocus induced by the MS lenses (i.e., asymmetry of the through-focus image changes about the distance focus) or to the general reduction in image contrast that the lenslets create in the peripheral field. Multiple segment spectacle lenses offer a valuable new approach to the control of myopia progression in children. Further work is required to clarify their mechanism of action and to optimise their design parameters.

Predicting axial length in patients with Marfan syndrome and ectopia lentis after modified capsular tension ring and intraocular lens implantation.

To predict the growth of axial length (AL) in patients with Marfan syndrome (MFS) and ectopia lentis (EL). Eye and ENT Hospital of Fudan University, Shanghai, China. Consecutive retrospective case series. Eyes were evaluated that had modified capsular tension ring and intraocular lens implantation. The rate of axial length growth (RALG) was calculated using AL divided by log10-transformed age. A multivariable linear regression model of RALG was developed after validation. A total of 128 patients with Marfan syndrome (MFS) and EL were enrolled with a median follow-up duration of about three years. RALG was independent of age between 3 to 15 years old (P = 0.799) and decreased to zero thereafter (P = 0.878). Preoperative AL was associated with RALG in patients under 15 years old (P = 0.003). Beta values for the final model of RALG were as below: intercept (-9.794) and pre-operative AL (0.664). The postoperative AL was predicted as: postAL = preAL + RALG × log10((postAge + 0.6) / (preAge + 0.6)). The mean prediction error was -0.003 (95%CI, -0.386, 0.3791) mm and the mean absolute percentage error was 1.93% (95%CI, 0.73%, 3.14%). A Python-based calculator was developed to use the predicted AL in selecting IOL power and setting undercorrection. The AL growth of patients with MFS followed a logarithmic pattern and ceased at about age 15. A prediction model of postoperative AL was established for individual MFS patients between 3-15 years old, which could potentially optimize the IOL power selection.

Predicting future axial length in patients with paediatric cataract and primary intraocular lens implantation.

Creating a model to predict Axial Length (AL) growth in paediatric cataract and evaluating influence factors. Eyes with AL measured at surgery and at least one measurement after a 6-month period, from children with unilateral or bilateral cataract and primary IOL implantation, were evaluated. A "rate of axial length growth" (RALG) was calculated for every single eye using these AL measurements and log10 age. One average RALG was calculated for All Eyes and for the groups of Bilateral and Unilateral, Gender, Age at the Surgery, different Visual Acuity, Bilateral Excluded and Not-excluded eye, and Affected and Not-affected eye in unilateral, for comparisons. Average age at surgery from 76 children was 2.83 ± 2.74 (0.11-12.21) years with follow up of 2.84 ± 1.84 (0.52-8.17) years, 29 (37.66%) had unilateral cataract. A total of 357 AL measurements were used, average of 4.70 ± 2.13 (2-10) measurements per eye. The average RALG for all eyes was 4.51 ± 3.06. There were no RALG significant differences comparing Unilateral and Bilateral eyes (p = 0.51), Male and Female (p = 0.26), Age at Surgery <0.5 and >0.5 years old (p = 0.21), both eyes in Bilateral cases (p = 0.70) and Unilateral Affected and Not-affected eyes (p = 0.18). The equation Al = initial AL + slope × Log10 ((age + 0.6)⁄(initial age + 0.6)) estimates ALs in different ages. A model to predict AL growth in paediatric cataract was developed. Different studied factors did not significantly influence AL growth.

Evaluation of eye-related parameters and adverse events of rigid gas permeable contact lens and spectacles correction in infants with monocular aphakia after congenital cataract surgery: a retrospective clinical study

BackgroundCongenital cataract is currently one of the leading blindness-causing eye diseases in children. Surgical treatment only opens the visual pathway for children. The postoperative recovery of visual function is also dependent on effective optical correction and visual function training. In this study, we analyzed the changes in eye-related parameters, adverse events and the annual cost of rigid gas permeable contact lens (RGPCL) and spectacles correction in infants with monocular aphakia after congenital cataract surgery.MethodsTo analyze the postoperative visual acuity, strabismus, nystagmus, myopic shift, globe axial length growth, adverse events, patient adherence to patching, and annual cost for patients with unilateral congenital cataract who underwent cataract surgery. Rigid gas permeable contact lenses or spectacles were used to correct aphakia after congenital cataract.ResultsOf the 49 patients, 20 patients with unilateral aphakia who used RGPCL were in group 1. Group 2 comprised 14 patients with persistent fetal vasculature (PFV) who used RGPCL, and there were 15 patients with spectacles in group 3. In group 1, there were important improvements in visual acuity, strabismus and nystagmus. In groups 2 and 3, there were no significant improvements in visual acuity, strabismus or nystagmus. Patients with a good adherence to patching had better visual acuity after the operation than patients who did not, in groups 1 and 3. There were no significant differences in myopic shift or rate of globe axial length growth among the 3 groups. No patients in group 1 had ocular disease that affected visual acuity. The mean annual expenses of the RGPCL group was 3965 yuan, and the mean annual cost of spectacles was 1140 yuan to 2500 yuan.ConclusionRGPCL is a safe and effective optical correction method for patients with monocular aphakia after congenital cataract surgery. Spectacles are not an ideal optical correction. Using RGPCL to correct patients with PFV, the final visual acuity improved, but the difference was not statistically significant. There were no improvements in strabismus or nystagmus in patients with PFV.

Biometric changes in Indian pediatric cataract and postoperative refractive status.

Purpose:To prospectively evaluate the biometric changes in Indian pediatric cataract and postoperative refractive status.Methods:A total of 147 patients were recruited into three groups: age <6 months, age between 7 months and 18 months, and age between 19 and 60 months and prospectively observed for 6 months. Exclusion criteria were preterm birth, microphthalmia, microcornea, megalocornea, uveitis, glaucoma, and traumatic or complicated cataract. Axial length and keratometry, the primary outcome measures, were taken preoperatively under general anesthesia before surgery. These children were followed up for 6 months to look for refractive and biometric changes. T-test and linear regression with the logarithm of independent variables were done.Results:All unilateral cataractous eyes (n = 25) and randomly selected bilateral cases (n = 122) were included in the analysis, for a total of 147 eyes. Mean age was 17.163 ± 13.024 months; axial length growth was 0.21, 0.18, 0.06 mm/month, and keratometry decline was 0.083, 0.035, 0.001 D/month in age groups 0–6, 7–18, and 19–60 months, respectively. The visual acuity improved in log MAR from 1.020 to 0.745 at 6 months postoperatively. There was statistically significant (Spearman's correlation coefficient = –0.575, P < 0.001) between age and postoperative refraction. There were no intraocular lens (IOL)-related complications seen in the immediate postoperative period. Peripheral opacification was seen in 102 eyes and central opacification in 1 eye at a 6-month follow-up.Conclusion:Indian eyes have a lower rate of axial length growth and keratometry change in comparison with western eyes implying smaller undercorrection in emmetropic IOL power for Indian pediatric eyes to achieve a moderate amount of hyperopia.

The change in axial length in the pseudophakic eye compared to the unoperated fellow eye in children with bilateral cataracts

To compare the change in ocular axial length of the pseudophakic eye versus the fellow eye in children with bilateral cataracts who had surgery in only one eye. In this prospective cohort study, 50 eyes of 25 children with bilateral lamellar cataracts were analyzed. A complete ophthalmic examination and evaluation of axial length measurements by contact ultrasound biometry were performed in all eyes undergoing cataract surgery with IOL implantation and in contralateral eyes. The primary outcome measure was the percentage rate of growth between the final and initial measurements, defined as the initial minus the final measurement, with the difference being divided by the initial measurement and the result multiplied by 100. Children aged 4-10 years of age were followed for a mean of 28.5 months. The values for axial length percentage rate of growth were significantly lower in pseudophakic eyes than in the unoperated, contralateral eyes (0.64% vs 2.09%, P < 0.05). Final visual acuity, follow-up time, and initial axial length did not affect the results. Pseudophakic eyes with posterior capsule opacification that underwent neodymium YAG laser showed a significantly higher rate of growth than unoperated eyes. Axial length in children older than 4 years showed a trend toward stabilization, with lower changes in axial length measurements in pseudophakic eyes and a higher rate of axial growth in contralateral eyes.

Management Options in Pediatric Cataract

Pediatric cataract surgery remains a very important and difficult problem to manage and involves a team effort, the most important members of which are parents. While dramatic advances have occurred in this field during the past 10 years, some technical aspects of surgery, changing refraction, and functional outcome continue to pose significant problems. Manual capsulorhexis remains the gold standard for a successful outcome of pediatric cataract surgery as well as in deciding intraocular lens (IOL) placement. Primary management of the posterior capsule with or without anterior vitrectomy is mandatory depending on age of the child at surgery. Primary implantation of the IOL after cataract removal is gaining popularity, even for infants and young children. Predicting axial growth and the refractive change that accompanies it is one of the major challenges for the long-term care of children after surgery. The evaluation of rate of axial growth and its correlation with age at surgery, laterality, aphakia/pseudophakia, and visual axis obscuration is a positive step in this direction. Finally, appropriate visual rehabilitation and amblyopia therapy are the cornerstones for the child’s final visual development.

Dynamic shear-influenced collagen self-assembly

The ability to influence the direction of polymerization of a self-assembling biomolecular system has the potential to generate materials with extremely high anisotropy. In biological systems where highly-oriented cellular populations give rise to aligned and often load-bearing tissue such organized molecular scaffolds could aid in the contact guidance of cells for engineered tissue constructs (e.g. cornea and tendon). In this investigation we examine the detailed dynamics of pepsin-extracted type I bovine collagen assembly on a glass surface under the influence of flow between two plates. Differential Interference Contrast (DIC) imaging (60×-1.4NA) with focal plane stabilization was used to resolve and track the growth of collagen aggregates on borosilicate glass for 4 different shear rates (500, 80, 20, and 9 s −1). The detailed morphology of the collagen fibrils/aggregates was examined using Quick Freeze Deep Etch (QFDE) electron microscopy. Nucleation of fibrils on the glass was observed to occur rapidly (∼2 min) followed by continued growth of the fibrils. The growth rates were dependent on flow in a complex manner with the highest rate of axial growth (0.1 μ/s) occurring at a shear rate of 9 s −1. The lowest growth rate occurred at the highest shear. Fibrils were observed to both branch and join during the experiments. The best alignment of fibrils was observed at intermediate shear rates of 20 and 80 s −1. However, the investigation revealed that fibril directional growth was not stable. At high shear rates, fibrils would often turn downstream forming what we term “hooks” which are likely the combined result of monomer interaction with the initial collagen layer or “mat” and the high shear rate. Further, QFDE examination of fibril morphology demonstrated that the assembled fibrillar structure did not possess native D-periodicity. Instead, fibrils comprised a collection of generally aligned, monomers which were self-assembled to form a fibril-like aggregate. In conclusion, though constant shear-rate clearly influences collagen fibrillar alignment, the formation of highly-organized collagenous arrays of native-like D-banded fibrils remains a challenge. Modulation of shear in combination with surface energy patterning to produce a highly-aligned initial mat may provide significant improvement of both the fibril morphology and alignment.

Axial eye length growth and final refractive outcome after unilateral paediatric cataract surgery

AimTo compare the axial eye length growth of the two fellow eyes within one patient after unilateral paediatric cataract surgery and to assess changes in refraction and keratometry.Patients/methodsA retrospective study...

Changes in interocular axial length after pediatric cataract surgery

To explore the hypothesis that preoperative interocular axial length difference changes after pediatric cataract intraocular lens implantation surgery to meet the measurement of the fellow eye. Retrospective chart review. Eyes with traumatic and secondary cataract, lens subluxation, or postoperative glaucoma were excluded. In bilateral cataract cases, only right eye data were included. In addition, eyes were included only if axial length data for both eyes were available before surgery and at follow-up equal to or greater than the age at surgery. Forty-seven eyes fit the inclusion criteria. Average age at surgery and follow-up was 2.2 +/- 2.2 and 5.6 +/- 2.9 years, respectively. Three groups were formed based on the preoperative interocular axial length difference: < -0.2, group 1; >or= -0.2, and <or=0.2, group 2; >0.2, group 3. Average age at surgery between these three groups was not significantly different (p = 0.82), nor was age at follow-up between the groups (p = 0.66). The change in interocular axial length difference (postoperative interocular axial length difference minus preoperative interocular axial length difference) was significant between the three groups (0.3, 0.2, -0.4 mm, respectively; p = 0.02). The average rate of axial length growth was significantly different between three groups (3.7, 2.4, 2.5 mm, respectively; p = 0.03). Eyes with a shorter axial length than the fellow eye showed postoperative rate of axial growth that exceeded the growth rate of eyes with a longer interocular axial length. These growth rates resulted in a postoperative trend of intraocular axial length difference toward zero.

Confined growth of a vapour bubble in a capillary tube at initially uniform superheat: Experiments and modelling

Bubble growth was triggered in a capillary tube closed at one end and vented to the atmosphere at the other and initially filled with uniformly superheated water. Measurements of the rate of axial growth and the varying pressure at the closed end were used to test under these simplified conditions assumptions employed in one-dimensional models for bubble growth applicable to the more complex conditions of confined-bubble flow boiling in micro-channels. Issues included the thickness of the liquid films round confined bubbles and changes in saturation temperature due to the changes in pressure generated by bubble motion. Modelling features requiring further attention were identified, such as the possibility of “roll-up” of the liquid film due to a large dynamic contact angle.

Update on bimanual microincisional cataract surgery

The purpose of this article is to highlight the major issues associated with bimanual microincisional cataract surgery and to review the recent literature addressing this subject. Bimanual microincisional cataract surgery has been performed successfully using all of the major phacoemulsification platforms. Technological advances in ultrasound power management and fluidics have improved the safety profile and efficiency of this technique. New intraocular-lens designs and surgical maneuvers permit intraocular-lens insertion through corneal incisions measuring 2 mm or less. Clinical results achieved with bimanual microincisional cataract surgery and new microincision lenses are comparable to those obtained with conventional coaxial phacoemulsification and established intraocular lenses. Bimanual microincisional cataract surgery is a promising surgical technique that continues to grow as phacoemulsification technology and intraocular-lens designs evolve.

Rate of axial growth after congenital cataract surgery

To evaluate the rate of axial growth after congenital cataract surgery. Prospective observational case series. Rate of axial growth of 158 eyes (79 children < 10 years) undergoing surgery was correlated with age at surgery, laterality, and visual axis obscuration. After measuring axial length (AL) at each follow-up, the mean AL was calculated, adding the AL of all eyes divided by their total number. Rate of axial growth is the percentage difference between preoperative mean AL and mean AL at last follow up. The temporal profile of RAG is the difference between two consecutive mean ALs with respect to the previous reading. The follow-up period was 58.96 +/- 2.02 months. The student' paired t test and independent sample t test were applied. The main outcome measure was RAG. Rate of axial growth in children operated at < or = 1 year (23.5%) was significantly higher than in those at < or = 3 years (4.8%; P = .0001, confidence interval [CI] 1.05-3.2) and at < or = 10 years (4.3%; P = .0001, CI 1.3-3.1). In children operated at <or = 1 year, temporal profile of RAG was higher in the first 2 years after surgery. Rate of axial growth was higher in patients with unilateral pseudophakia at < or = 1 year (25.53%) than in age-matched patients with bilateral pseudophakia (18.50%; P = .001, CI -13 to -0.2). Rate of axial growth was negligible in children with visual axis obscuration in any group. Rate of axial growth is higher in children < or = 1 year and increases until the second year after surgery. Unilateral pseudophakia revealed accelerated growth compared with bilateral pseudophakia. Visual axis obscuration does not influence rate of axial growth.

The susceptible period for deprivation-induced myopia in tree shrew.

To examine the susceptible period for deprivation-induced myopia, six groups of tree shrew pups (Tupaia glis belangeri) were monocularly deprived for 12 days with an opaque occluder starting 7, 15, 21, 33, 48, or 63 days after natural eyelid opening. Compared to the untreated fellow control eye, significant myopia and vitreous chamber elongation were produced by the deprivation in all six groups. The effect was greater in the middle three groups in comparison with the youngest and the two oldest groups and the amount of induced myopia and axial elongation was not proportional to the normal rate of axial growth. The peak period of susceptibility was between approximately 15 and 45 days after eye opening during the juvenile, slow-elongation phase of ocular development when the eye is within 7% of its adult axial length. Significant myopia and axial elongation were also induced in adult animals by 70 days of monocular deprivation. To examine recovery from deprivation-induced myopia, the occluder was removed at the end of the 12 day deprivation period. After an additional 48 days of binocular visual experience, no significant myopia was present in the previously deprived eyes in any experimental group. During the recovery period, the elongation rate of the previously deprived eyes was reduced in comparison with the control eyes while normal corneal flattening and lens development continued, thus reducing the myopia. No difference in corneal curvature, relative to the untreated control eyes, was found after deprivation or after the recovery period. Data are presented which suggests that changes in the thickness of the choroid may occur in this mammal during deprivation and recovery that are in the same direction, but of smaller magnitude, than those reported in the chicken. The results of this study provide evidence that visually guided emmetropization occurs in this mammalian species during a period of ocular development analogous to the juvenile period in humans.

Diurnal growth rhythms in the chicken eye: relation to myopia development and retinal dopamine levels.

1. If the eyes of young chickens are deprived of clear vision by translucent occluders, they develop considerable amounts of axial myopia within days. At the same time, the day time retinal dopamine levels drop by about 30%. Because the retinal dopamine levels of normally sighted chicks also differ diurnally and are low at night, we expected that the rate of axial eye growth might also differ during this time. 2. Unexpectedly, eyes grew in length only during the day (about 0.13 mm/day) and even shrank during the night (about -0.04 mm/night, average net growth +0.09 mm in 24 h). 3. If the eyes were occluded, they grew both during the day and also at night (average net growth: +0.16 mm in 24 h). Therefore, development of deprivation myopia was a result of the lack of growth inhibition at night rather than of excessive growth during the day when the actual deprivation occurred. 4. Suppression of dopaminergic retinal pathways by intravitreal injections of the neurotoxin 6-hydroxy-dopamine (6-OHDA) also suppressed development of deprivation myopia and it restored the growth inhibition at night. With normal visual experience, the drug had no effect on axial eye growth and refractive state. 5. Diurnal growth rhythms of the eyes disappeared under continuous light.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacological modification of eye growth in normally reared and visually deprived chicks

Regular injections of the gliotoxins D-alpha-aminoadipic acid and L-alpha-aminoadipic acid were made into the vitreous chamber of the eyes of newly-hatched chicks reared either in a normal visual environment or under conditions of monocular occlusion. Striking differences in the growth rates of the eyes from the different groups were observed. Injection of D-alpha-aminoadipic acid, which causes the Müller glial cells to swell and diminishes the retinal OFF-response, resulted in a marked increase in the rate of axial growth of the eye compared with normal eyes. However, injection of D-alpha-aminoadipic acid into occluded eyes caused a lesser growth rate than was observed in occluded control eyes. By contrast, injection of L-alpha-aminoadipic acid, which also causes severe glial swelling and abolishes the retinal ON-response, caused reduced eye growth in non-occluded eyes. However, injection of L-alpha-aminoadipic acid into occluded eyes caused eye growth in excess of that recorded in the occluded controls. We concluded that the different growth rates observed is more likely a result of the disruption of the neural ON and OFF mechanisms than of the indisposition of the Müller cells.

Characteristics of Whisker Growth in Amorphous Silicon

The growth of amorphous silicon whiskers grown by thermal decomposition of silane (SiH4) in the temperature range between 500 and 800°C in an argon atmosphere has been investigated in detail. A thin gold film (about 200 Å) on the substrate seems to act as the most effective catalyzer for the whisker growth. The time rate of axial growth at the beginning of each growth curve seems to be proportional to the partial pressure of SiH4. Radial growth proceeds at a constant rate and remains constant even after termination of the extension in length. The two mechanisms of elongation and thickening are controlled by independent activation processes whose activation energies are 0.73 eV and 2.1 eV respectively.

Role of attrition and occlusal contact in the physiology of the rat incisor. 3. Prevention of attrition and occlusal contact in the nonarticulating incisor.

Removal of occlusal contact in the absence of attrition liberates the growth potential of the rat incisor, which is expressed in a doubled rate of axial growth and eruption. The differentiation times, the life spans and the rates of apposition of dental hard tissue-forming cells, however, are independent of the rates of growth and eruption.