Eye Length Research Articles

Reduced Retinal Vascular Density and Skeleton Length in Amblyopia.

This study aimed to investigate the possible relationship between retinal vascular abnormalities and amblyopia by analyzing vascular structures of fundus images. In this observational study, retinal fundus images were collected from 36 patients with unilateral amblyopia, 33 patients with bilateral amblyopia, and 36 healthy control volunteers. We developed a customized training algorithm based on U-Net to digitalize the vasculature in the fundus images to quantify vascular density (area and fractal dimension), skeleton length, and number of bifurcation points. For statistical comparisons, this study divided participants into two groups. The amblyopic eyes and the fellow eyes of patients with unilateral amblyopia formed the paired group, while bilateral amblyopic patients and healthy controls formed the independent group. In the paired group, the vascular area (P = 0.007), vascular fractal dimension (P = 0.007), and vascular skeleton length (P = 0.002) of the amblyopic eyes were significantly smaller than those of the fellow eyes. In the independent group, significant decreases in the vascular fractal dimension (P = 0.006) and skeleton length (P = 0.048) were observed in bilateral amblyopia compared to control. The vascular area was also significantly correlated with best-corrected visual acuity in amblyopic eyes. This study demonstrated that retinal vascular density and skeleton length in amblyopic eyes were significantly smaller compared to control, indicating an association between the changes in retinal vascular features and the state of amblyopia. Our algorithm presents amblyopic retinal vascular changes that are more biologically interpretable for both clinicians and researchers.

A Morphometric Study of the Pars Plana of the Ciliary Body in Human Cadaver Eyes.

This study aimed to determine the pars plana length in postmortem human eyes using advanced morphometric techniques and correlate demographics to ocular metrics such as age, sex, ethnicity, and axial length. Between February and July 2005, we conducted a cross-sectional observational study on 46 human cadaver eyes deemed unsuitable for transplant by the SBO Eye Bank. The morphometric analysis was performed on projected images using a surgical microscope and a video-microscopy system with a 20.5:1 correction factor. The pars plana length was measured three times per quadrant, with the final value being the mean of these measurements. Of the 46 eyes collected, 9 were unsuitable for the study due to technical constraints in conducting intraocular measurements. Overall, the average axial length was 25.20 mm. The average pars plana length was 3.8 mm in all quadrants, with no measurements below 2.8 mm or above 4.9 mm. There were no statistically significant variations across quadrants or with age, sex, axial length, or laterality. Accurately defining the pars plana dimensions is crucial for safely accessing the posterior segment of the eye and minimizing complications during intraocular procedures, such as intravitreal injections and vitreoretinal surgeries.

Evaluating the microcirculation of the dome-shaped macula and its complications in adults with highly myopic eyes by swept-source optical coherence tomography angiography.

The aim of this study was to investigate the microcirculatory characteristics of the dome-shaped macula (DSM), its complications in highly myopic eyes and to explore the factors associated with a DSM. This cross-sectional case-control study included a total of 98 subjects (98 eyes): 49 eyes with DSM and 49 eyes without DSM. The axial length (AL) of the myopic eyes was matched 1:1 to eliminate the effect of AL differences on the results. Choroidal (CT) and scleral thickness (ST) and other structural parameters were assessed by swept-source optical coherence tomography (SS-OCT). OCT angiography was used to measure microcirculatory parameters in highly myopic eyes. Subjects with DSM had thinner subfoveal choroidal thickness (46.01 ± 13.25 vs. 81.62 ± 48.26 μm; p < 0.001), thicker subfoveal scleral thickness (SFST; 331.93 ± 79.87 vs. 238.74 ± 70.96 μm; p < 0.001) and thinner foveal CT (66.86 ± 24.65 vs. 107.85 ± 52.65 μm; p < 0.001) compared to subjects without DSM. The foveal choroidal perfusion area (0.72 ± 0.04 vs. 0.76 ± 0.04 mm2; p < 0.001) and foveal choroidal vascularity index (0.15 ± 0.04 vs. 0.33 ± 0.14; p < 0.001) were significantly lower in eyes with DSM. Retinoschisis (81.6% vs. 38.8%; p < 0.001) was more common in eyes with DSM. Eyes with horizontal DSM had worse best-corrected logMAR visual acuity than eyes with round DSM (0.34 ± 0.22 vs. 0.23 ± 0.22; p = 0.03). DSM height (98.95 ± 65.17 vs. 104.63 ± 44.62 μm; p = 0.05) was lower in the horizontal DSM. SFST (OR = 1.06, p = 0.04) and foveal choroidal vascularity index (OR = 0.711, p = 0.02) were significantly associated with DSM. DSM width (p < 0.001), foveal choroidal perfusion area (p = 0.01), foveal choriocapillaris perfusion area (p = 0.02) and parafoveal choroidal vascularity index (p = 0.03) were the most significantly associated factors with DSM height. The microcirculatory characteristics of eyes with DSM differed from those without DSM. Microcirculatory abnormalities were significantly associated with a DSM. The height of the DSM was associated with decreased blood perfusion.

Influence of Aberration-Free, Narrowband Light on the Choroidal Thickness and Eye Length.

To determine whether light chromaticity without defocus induced by longitudinal chromatic aberration (LCA) is sufficient to regulate eye growth. An interferometric setup based on a spatial light modulator was used to illuminate the dominant eyes of 23 participants for 30minutes with three aberration-free stimulation conditions: (1) short wavelength (450nm), (2) long wavelength (638nm), and (3) broadband light (450-700nm), covering a retinal area of 12°. The non-dominant eye was occluded and remained as the control eye. Axial length and choroidal thickness were measured before and after the illumination period. Axial length increased significantly from baseline for short-wavelength (P < 0.01, 7.4 ± 2.2 µm) and long-wavelength (P = 0.01, 4.8 ± 1.7 µm) light. The broadband condition also showed an increase in axial length with no significance (P = 0.08, 5.1 ± 3.5 µm). The choroidal thickness significantly decreased in the case of long-wavelength light (P < 0.01, -5.7 ± 2.2 µm), but there was no significant change after short-wavelength and broadband illumination. The axial length and choroidal thickness did not differ significantly between the test and control eyes or between the illumination conditions (all P > 0.05). Also, the illuminated versus non-illuminated choroidal zone did not show a significant difference (all P > 0.05). All stimulation conditions with short- and long-wavelength light and broadband light led to axial elongation and choroidal thinning. Therefore, light chromaticity without defocus induced by LCA is suggested to be insufficient to regulate eye growth. This study helps in understanding if light chromaticity alone is a sufficient regulator of eye growth.

Ciliary muscles contraction leads to axial length extension--The possible initiating factor for myopia.

This study aimed to investigate the underlying factors driving the onset of myopia, specifically the role of the ciliary muscle's contraction in the elongation of the axial length of the eye. The retrospective study was conducted utilizing data from three ophthalmic centers in Shanghai and Beijing. Both Chinese and Caucasian children were involved. The axial length of the subjects' eyes was measured in both relaxed and contracted state of the ciliary muscle. A comprehensive mechanical model was also developed to observe the influence of ciliary muscle contraction on the axial length. This study included a sample of 198 right eyes of 198 myopic children. Of these, 97 were male and 101 were female, 126 were of Chinese ethnicity and 72 were Caucasian. The age of onset for myopia ranged from 5.9 to 16.9 years old. The axial length of the eye decreased 0.028 ± 0.007mm following dilation, indicating relaxation of the ciliary muscle (t paired student = 15.16, p = 6.72 x 10-35). In contrast, ciliary muscle contraction resulted in an increase in axial length. Considering proportionality, a significant 90.4% (179 eyes) exhibited a reduced axial length, while a minor 9.6% (19 eyes) demonstrated an increase post-mydriasis. Finite element modeling demonstrated that muscle contraction caused a tension force that transmits towards the posterior pole of the eye, causing it to extend posteriorly. The contraction of the ciliary muscle leads to an extension of the axial length. This could potentially be the initiating factor for myopia.

A Case of Excessive Axial Length Elongation Following Retinal Detachment Vitrectomy

Purpose: To report a case of excessive axial length elongation following vitrectomy for rhegmatogenous retinal detachment.Case summary: A 21-year-old male patient presented to our hospital with visual impairment. The patient had previously undergone computed tomography in our emergency room for a facial contusion 3 years prior to his current visit. Axial lengths of 27.23 mm in the right eye and 27.62 mm in the left eye were recorded at that time. The patient had no previous ocular history. Fundus examination revealed extensive retinal detachment with macular involvement and hypotony retinopathy in the left eye. Retinal detachment surgery was subsequently performed on the left eye. Following the surgery, intraocular pressure in the left eye increased and intraocular pressure-lowering medications were administered. At 3 months postoperatively, the patient developed additional retinal detachment in the right eye, prompting retinal detachment surgery. Unlike the contralateral eye, the intraocular pressure remained well-controlled postoperatively. Axial length measurement was performed due to the complaint of left eye protrusion. The axial lengths were 27.76 mm and 31.41 mm in the right and left eyes, respectively. There was a significant increase in the axial length of the left eye but not in that of the right eye compared to 3 years prior.Conclusions: Gas tamponade, preoperative ocular hypotension, and postoperative ocular hypertension can cause excessive axial length elongation in cases of rhegmatogenous retinal detachment in young patients with high myopia.

Ultrastructure and morphometric characteristics of &lt;i&gt;Oecophylla smaragdina&lt;/i&gt; (Fabricius, 1775) (Hymenoptera: Formicidae)

In this study, we explored various aspects of Oecophylla smaragdina, a potential biocontrol agent, evolution by examining its morphometric characteristics. We employed an intensive All-out search method (AOSM) to gather specimens from multiple locations in Vadakku Karaseri, Tamil Nadu. Our analysis involved measuring 16 morphological traits and indices, including Total Length, Head Width, Head Length, Eye Length and more, using specimens from five colonies in each locality. By calculating various morphometric indices, we assessed specific features and conducted a Principal Component Analysis (PCA) to determine the significance of head-related variables, antennae, and body size in shaping morphometric variation. Our study also revealed positive and negative associations between different morphometric variables, as highlighted by Pearson correlation coefficients. Furthermore, we used a Scanning Electron Microscope to examine the ultrastructure of the abdomen, revealing distinct features such as a one-jointed pedicel and modifications of the poison gland and stings. This comprehensive research provides valuable insights into O. smaragdina morphometric characteristics, enhancing our understanding of its variability and potential adaptations in various habitats.

Axial length, more than aging, decreases the thickness and superficial vessel density of retinal nerve fiber layer in non-glaucomatous eyes

PurposeThis study seeks to build a normative database for the vessel density of the superficial retina (SVD) and evaluate how changes and trends in the retinal microvasculature may be influenced by age and axial length (AL) in non-glaucomatous eyes, as measured with optical coherence tomography angiography (OCTA). MethodsWe included 500 eyes of 290 healthy subjects visiting a county hospital. Each participant underwent comprehensive ophthalmological examinations and OCTA to measure the SVD and thickness of the macular and peripapillary areas. To analyze correlations between SVD and age or AL, multivariable linear regression models with generalized estimating equations were applied.ResultsAge was negatively correlated with the SVD of the superior, central, and inferior macular areas and the superior peripapillary area, with a decrease rate of 1.06%, 1.36%, 0.84%, and 0.66% per decade, respectively. However, inferior peripapillary SVD showed no significant correlation with age. AL was negatively correlated with the SVD of the inferior macular area and the superior and inferior peripapillary areas, with coefficients of −0.522%/mm, −0.733%/mm, and −0.664%/mm, respectively. AL was also negatively correlated with the thickness of the retinal nerve fiber layer and inferior ganglion cell complex (p = 0.004).ConclusionAge and AL were the two main factors affecting changes in SVD. Furthermore, AL, a relative term to represent the degree of myopia, had a greater effect than age and showed a more significant effect on thickness than on SVD. This relationship has important implications because myopia is a significant issue in modern cities.

Chemical Cues Released by Predators’ Consumption of Heterospecific Prey Alter the Embryogenesis of Zebrafish

Environmentally cued hatching is prevalent, diverse, and crucial to many animals’ survival. Fish embryos use a variety of chemical cues to initiate hatching to avoid potential predators, yet the function of chemical cues released from the predatory consumption of heterospecific prey is largely unknown. Zebra cichlids (Metriaclima estherae) are ferocious predators that can feed on medaka (Oryzias latipes), though it is impossible for this to occur in their natural habitat. Zebrafish (Danio rerio) embryos have been employed as experimental subjects due to their sensitivity to a variety of chemical signals. In this study, zebrafish embryos were subjected to three types of chemical signals: predator cues (PCs, released from cichlids), heterospecific cues (HCs, released from medaka), and heterospecific dietary cues (HDCs, released from cichlids that have ingested medaka). As a result, the hatching times of zebrafish embryos were accelerated by 6.8% and 12.6% by PCs and HDCs, respectively. PCs and HDCs cause significantly reduced morphology in zebrafish embryos, including regarding total length, eye length, dorsal fin length, trunk height, caudal fin height, and body cavity, and increase yolk sac height. The PCs and HDCs diminished the larvae’s motion at 120 and 144 h post fertilization (hpf), which could be attributed to non-developmental embryogenesis. Overall, the impacts of HDCs on embryonic hatching, developmental morphology, and locomotor were more pronounced in comparison with PCs. Our findings demonstrate that predators’ dietary cues, even those released after predation on heterospecific prey, can modify embryogenesis, highlighting the critical functions of chemical signals in predation risk assessment using embryos.

A pilot study of axial length changes associated with myopia control spectacles in subjects reading under mesopic conditions

PurposeTo investigate whether axial length changes in subjects wearing myopia control spectacles under mesopic conditions. MethodsYoung users of monofocal spectacles with myopic spherical equivalent ranging from −1.00 D to −5.00 D were enrolled prospectively. Subjects were tested while using a pair of special defocus spectacles with a central zone including the distance myopic correction and a peripheral zone with an addition of +3.50 D. Subjects first read an online book with black letters on white background on a desktop computer with their monofocal spectacles for 20 minutes and then read with special defocus spectacles for another 20 minutes. Reading took place in a darkened room under 20 lux illumination. Before and after these periods, axial length of the right eye was measured ten times using the Lenstar, and average measurements were recorded. ResultsThe 11 subjects in this pilot study had a mean age of 20.9 ± 7.7 years, and 1 was female. Their mean spherical equivalent of the right eyes was −3.20 ± 2.29 D. As expected, axial length increased by 8.2 ± 9.4 μm (P < 0.01) after 20 minutes of reading with monofocal spectacles in low light. When reading with defocus spectacles under the same conditions, the axial length saw an additional, nonsignificant change of 2.2 ± 12.2 μm (P = 0.56). ConclusionsWhen reading in mesopic conditions, the axial length in study subjects did not return to baseline values with myopia control spectacles.

HISTOLOGICAL FEATURES OF ETHAMBUTOL INDUCED MICE EYES: A PRE- EXPERIMENTAL STUDY ON TOXIC OPTIC NEUROPATHY CASE

Abstract&#x0D; Introduction &amp; Objectives : Toxic Optic Neuropathy (TON) is a visual disease caused by toxic substances damaging the optic nerve. It can be caused by inflammation, infection, or long-term drug use. Over 10% of ethambutol- treated optic neuropathy patients developed major complications. Cellular changes should be observed histologically. This study examines ethambutol-induced mice's eye histology in the fibrous, vasculous, nervous tunica, optical media, and optic nerve tissue.&#x0D; Methods : This pre-experimental study used 20 eyes of 10 white mice aged 1-2 weeks weighing 50-65 grams. Group 1 consisted of healthy mice without therapy and group 2 received 35 mg/kgBW/day of ethambutol for 60 days. (group 2). Hematoxylin eosin staining was used to observe binocular experimental animal eyes after enucleation. All measurements used Olympus® CX-20 microscope with 40x objective resolution.&#x0D; Results : The average thickness of the cornea was 72.238 ± 10.542 and 60.572 ± 10.25, while the sclera was 336.533±40.851 μm and 331.339±34.219 μm. In groups 1 and 2, no significant changes were foundin the cell layer morphology of both tissues (p &gt; 0.05). Iris, ciliary body, and choroid were observedin the tunica vasculosa. Groups 1 and 2 had eye and ciliary body lengths of 595.148±137.805 μm and 497.705±213.866 μm, respectively, and choroid thicknesses of 161.369±37.925 and 162.605±25.160 (p&gt;0.05). Group 1 had 402.268±55.666 μm retinal thickness in the tunica nervosa, while group 2 had 399.854±27.585 (p&gt;0.05).&#x0D; Conclusion : Ethambutol-induced and normal experimental animals had substantial histological differences in optic nerve thickness, but no significant difference in the other ocular structures.

Diagnosis of posterior staphyloma using the radius of steepest curvature among retinal pigment epithelium segmentation line measured by optic coherent tomography

PurposeTo investigate a novel marker to diagnose posterior staphylomas by measuring the radius of the steepest curvature on the retinal pigment epithelium (RPE) segmentation line using optical coherence tomography (OCT).Study DesignRetrospective Cross-sectional Study.MethodsThe authors developed a prototype software to measure the radius of curvature on the RPE segmentation line of OCT. Twelve images of 9-mm radial OCT scans were used. The radius of curvature was measured at the steepest area of the RPE segmentation line, and the macular curvature (MC) index was calculated based on its reciprocal. Based on the wide-field fundus findings, the study sample was divided into three groups: definite posterior staphyloma, no posterior staphyloma, and undetermined. The differences of MC index among the groups and the correlation between the MC index, age, and axial length were analyzed.ResultsThe present study analyzed 268 eyes, with 54 (20.1%) with definite posterior staphyloma, 202 (75.4%) with no posterior staphyloma, and 12 (4.5%) with undetermined disease status. A maximum MC index of 37.5 was observed in the group with no posterior staphyloma, which was less than the minimum MC index of 42.7 observed in the group with definite posterior staphyloma. The MC index had strong correlations with the axial length and age in eyes with high myopia.ConclusionsEyes with posterior staphyloma have a steeper curvature than those with radius 8.44 mm, while eyes without posterior staphyloma do not. MC index 40 (radius 8.44 mm) might act as a reference to distinguish between those with and those without posterior staphyloma.

Baseline Accommodation and Binocular Vision Measures in Malay Schoolchildren Enrolled in the Myopia Control Study Using Spectacle Lenses in Kuala Lumpur.

Myopia control lenses have been shown to modify visual function; however, it is arguable if these changes are short-term or long-term. We investigated the changes in accommodative behaviour and binocular vision functions of Malay myopic children who participated in a myopia control trial utilising spectacle lenses (n = 40). This article presents baseline accommodation and binocular vision measurements. The mean (± SD) age, spherical equivalent measured by cycloplegic autorefraction, and axial length (AL) for the right eyes were 10.00 ± 1.47 years, -3.02 ± 1.20 D, and 24.42 ± 0.93 mm, respectively. All participants had good distance and near visual acuities with high-contrast charts (100%), which were significantly better than low-contrast charts (10%) (p < 0.001). The mean (± SD) accommodative lag at baseline was 1.14 ± 0.35 D, while monocular and binocular accommodative amplitudes were 15.35 ± 2.07 D and 16.82 ± 2.27 D, respectively. Malay schoolchildren in this study were more esophoric at near compared to distance, with an accommodative-convergence over accommodation (AC/A) ratio of 5.64 ± 0.66 ∆/D. A higher degree of myopia was found to be associated with a longer AL (r = -0.49, p < 0.05) and higher esophoria at near (r = -0.46, p < 0.05). These baseline measures are consistent with data from other studies showing that myopic children have a high accommodative lag, an elevated AC/A ratio, a longer AL, and are more esophoric at near. The measures reported herein will serve as a basis for examining changes that occur within 12 months of wearing myopia control spectacle lenses.

Peripheral Eye Length Evaluation in Myopic Children Undergoing Orthokeratology Treatment for 12 Months Using MRI.

To investigate changes in peripheral eye length (PEL) in myopic children undergoing orthokeratology (Ortho-K) treatment for 12 months using MRI. The results were compared to single vision spectacle wearers (SVS). A total of 70 children with myopia (aged 8-9 years old) were recruited. A total of 45 children were fitted with Ortho-K, and 25 were fitted with SVS. The PEL and axial length (AL) were measured by using MRI 3-Tesla, whereas central and peripheral refraction (PR) measurements were conducted at ±30 degrees horizontally with nasal (N) and temporal (T) intervals of 10°, 20°, and 30° and with an open field autorefractometer (WAM-5500 Grand Seiko). All the measurements were conducted at the baseline and 12 months. The MRI analysis indicates that at 12 months, the SVS group showed more elongation of the PEL and AL at all eccentricities than the Ortho-K group did (p < 0.05). The Ortho-K group only showed significant PEL elongation beyond 20 degrees at N20, N30, T20, and T30 (p < 0.05); however, a significant reduction in the AL was detected in the center AL, N10, and T10 (p < 0.05). All eccentricities in the relative PR of the Ortho-K group were significantly more myopic than at the baseline (p < 0.05), whereas in the SVS group, all eccentricities in the relative PR were shown to be significantly more hyperopic than at the baseline (p < 0.05). The PEL and PR showed negative correlations at 12 months in the Ortho-K group. MRI analysis can be utilized to describe changes in PEL in myopic children. It appears that as myopia progressed in Ortho-K lens wearers, the PEL increased by a greater amount than the AL did; thus, the retina was reshaped to become increasingly oblate and to display peripheral myopic defocus.

A new lineage of pygidicranid earwigs from mid-Cretaceous amber of northern Myanmar (Dermaptera: Pygidicranidae)

Based on a well-preserved male specimen from mid-Cretaceous Kachin amber, we describe a new genus and its type species of earwig, Prodacnodes dupliforceps gen. et sp. nov. Prodacnodes has a unique combination of traits: large compound eyes, scape shorter than compound eye length, pronotum as broad as head, prosternum subtrapezoidal, wings present and fully developed, metatarsomere II not slanted apically, pygidium with short medioapical process, male external parameres with prominent subapical tooth mesally, and simple forceps. Our research contributes additional morphological features and information, enriching our comprehension of the lineages and diversity of Late Mesozoic earwigs.

The long and short of it: a comprehensive assessment of axial length estimation in myopic eyes from ocular and demographic variables.

Axial length, a key measurement in myopia management, is not accessible in many settings. We aimed to develop and assess machine learning models to estimate the axial length of young myopic eyes. Linear regression, symbolic regression, gradient boosting and multilayer perceptron models were developed using age, sex, cycloplegic spherical equivalent refraction (SER) and corneal curvature. Training data were from 8135 (28% myopic) children and adolescents from Ireland, Northern Ireland and China. Model performance was tested on an additional 300 myopic individuals using traditional metrics alongside the estimated axial length vs age relationship. Linear regression and receiver operator characteristics (ROC) curves were used for statistical analysis. The contribution of the effective crystalline lens power to error in axial length estimation was calculated to define the latter's physiological limits. Axial length estimation models were applicable across all testing regions (p ≥ 0.96 for training by testing region interaction). The linear regression model performed best based on agreement metrics (mean absolute error [MAE] = 0.31 mm, coefficient of repeatability = 0.79 mm) and a smooth, monotonic estimated axial length vs age relationship. This model was better at identifying high-risk eyes (axial length >98th centile) than SER alone (area under the curve 0.89 vs 0.79, respectively). Without knowing lens power, the calculated limits of axial length estimation were 0.30 mm for MAE and 0.75 mm for coefficient of repeatability. In myopic eyes, we demonstrated superior axial length estimation with a linear regression model utilising age, sex and refractive metrics and showed its clinical utility as a risk stratification tool.

Functional changes in the myopic retina compromise emmetropization

During emmetropization, the retina analyses the focus of the image and generates appropriate biochemical signals to control choroidal thickness and scleral growth. Using commercially available optical low coherence interferometry (the Lenstar LS 900), changes in eye length in the micrometre range can be picked up already after 30 min when young human subjects watch movies that were digitally filtered. We found that the emmetropic retina can distinguish real optical positive defocus from simulated/calculated defocus. It triggered choroidal thickening in the first case, and thinning in the second. Strikingly, the myopic retina was not responsive, and the choroid became thinner in both cases. Longitudinal chromatic aberration (LCA) would be a perfect signal to tell the retina where the focal plane is. We simulated chromatic defocus in our movies. Either the red or the blue plane of the RGB format was spatially filtered to simulate chromatic defocus. When blue was ‘in focus’, eyes became longer, but when red was ‘in focus’ eyes became shorter. Again, myopic eyes did not respond, suggesting that the myopic retina no longer responded to LCA. Taken together, we found that the myopic retina had undergone functional changes such that no growth‐inhibiting signal was generated. As a consequence, eye growth would become open loop, explaining why myopia does not inhibit itself.

Double-step calculation of the intraocular lens power in lens opacities excluding the measurement of axial eye length by optical biometry. A clinical case

The main source of intraocular lens (IOL) power calculation errors in phacoemulsification (PE) is axial length (AL) measurement inaccuracy in cases if optical biometry cannot be used.bto describe an original double-step method of IOL power calculation in lens opacities which exclude AL measurement with optical biometry.Material and methods. Patient S. (male, 71) with a bilateral immature cataract underwent right eye phacoemulsification (PE) with no IOL implantation. After that, AL was measured in the aphakic state with transparent optical media and used in combination with preoperative anterior segment biometry data to calculate the IOL power. In the second stage, a selected lens with an extended focus range was implanted.Results. The patient was examined and discharged on the second day after surgery with visual acuity OD 0.3 sph +0.25 cyl -0.75 ax150 = 0.5 and signs of moderate postoperative keratopathy. After 2 weeks, uncorrected visual acuity was as high as 0.9 and could not be further corrected by spectacle lenses. The patient was admitted for surgical treatment of the left eye cataract and also operated in two stages. The AL measured by the optical method in the aphakic state, was 0.31 mm less than that measured before the operation. Six months after PE with IOL implantation, distance visual acuity in both eyes was 1.2, the patient could use binocular vision for reading and PC work with no difficulty.Conclusion. The double-step approach to IOL power calculation is justified in cases of strong decrease of crystalline lens transparency, especially in complicated cases, for example, in high myopia or “premium” lens implantation, in which patients are especially sensitive to correct target refraction, even though this approach requires a delayed IOL implantation, which should take place after a precise calculation of AL taken in the aphakic state.

Forest age is a primary trait filter for saproxylic beetles in the southeastern United States

Many forests throughout the world consist of regenerating mature stands. Although these forests differ in many respects from old-growth (with a history of minimal human disturbance), they typically develop similar structural attributes over time. As a result, older mature forests may be of particular conservation value if they contain resources and microhabitats benefitting saproxylic (deadwood dependent) species. Species’ response to forest age may be driven by traits that relate to ecological functions or habitat preferences, such that species with less compatible traits for a local forest environment are “filtered” out. Thus, forest age may influence species’ distributions and the trait composition of assembled communities.The Piedmont region of the southeastern United States has experienced widespread forest regrowth over the past century due to agricultural abandonment. Today’s landscapes are largely characterized by mature forests that are becoming increasingly fragmented by suburbanization. Here, we assessed the filtering effects of forest age, landscape forest cover (LFC), and deadwood volume on saproxylic beetles in northeastern Georgia. Using historic aerial imagery to distinguish forest age (young = regrown after 1938; old = mature in 1938), we sampled beetles in mature forests of both age classes occurring along an LFC gradient. We measured five traits with hypothesized functional roles (body length, body width, body roundness, antenna length, eye length) for the 472 species captured. Using a joint species distribution model (JSDM), we tested trait-niche relationships (i.e., how traits influence species’ responses) and estimated community trait composition (mean and dispersion of trait values) along gradients of environmental filters.We found that forest age is a filter for several traits (six supported relationships with > 95 % posterior probability), but LFC and deadwood volume were less strongly related to fewer traits. Most notably, large species (typically having lower population sizes and requiring stable larval habitat) were filtered from young mature forests and low LFC. Thus, old mature forests with high LFC showed higher mean and dispersion of beetle body length. Sensory traits also showed responses, likely reflecting adult life under bark (eye length) or ability to detect resources or mates (antenna length). Body width and roundness showed inconsistent responses with regard to indicated functional roles. Our results show that forest age is a strong filter on saproxylic beetle communities in the southeastern United States. Old mature forests, despite their scarcity in the region, are important for species requiring habitat stability and for maintaining communities with diverse trait composition.

Influence of Ocular Biometry Parameters on the Predictive Accuracy of IOL Power Formulas in Patients with High Myopia.

The aim of this study was to investigate the influence of ocular biometry parameters on the predictive accuracy of 10 intraocular lens (IOL) power formulas in patients with high myopia (HM). We analyzed 202 eyes of 202 patients. The ocular biometry was determined preoperatively using an IOLMaster700. The associations between the biometry parameters and the prediction error (PE) 1month postoperatively were assessed. HM was defined as an axial length exceeding 26.50mm. In patients with HM (n = 108), the K6, Emmetropia Verifying Optical (EVO), Olsen, and Barrett UniversalII (BUII) formulas had the lowest absolute PEs among the 10 formulas. The ocular biometry parameters were not associated with the PE of K6, EVO, Olsen, or BUII. A longer axial length in HM eyes was associated with myopic outcomes by Kane, Hoffer QST, and VRF and hyperopic outcomes by Holladay2 and T2. Steeper keratometry, a deeper anterior chamber, and a thicker lens were associated with a hyperopic shift in HM eyes when using VRF, Kane, and Hoffer QST, respectively. In patients without HM (n = 94), there was no difference between the formulas in absolute PE. The significant associations between the biometry parameters and PE in patients with HM were not present in patients without HM. K6, EVO, Olsen, and BUII displayed high accuracy in HM eyes and were not influenced by preoperative biometry parameters. For the remaining formulas, the preoperative keratometry, anterior chamber depth, lens thickness, and axial length were possible error sources underlying an inaccurate IOL power prediction in patients with HM.