Mean Axial Length Research Articles

Morphology and incidence of drusen-like deposits in peripheral retina of eyes with high myopia.

To determine the morphology and incidence of peripheral drusen-like deposits (DLDs) in eyes with pathological myopia (PM) using ultra-widefield (UWF) fundus photographs and UWF optical coherence tomographic (OCT) images. Retrospective, observational case series study. We reviewed the medical records of 676 patients (1352 eyes) with high myopia (HM) who were examined in the Advanced Clinical Centre for Myopia between 2017 and 2021. The main outcome measures were the incidence and morphological characteristics of the DLDs in the peripheral retina detected by ultra-widefield (UWF) imaging devices. Sixty-six of the 1352 (4.9%) eyes had peripheral DLDs. In 5 eyes, the DLDs were found at the staphyloma edge. The mean age of the patients was 70.0 ± 13.0 (range, 46.0-92.0) years, and the mean axial length was 29.8 ± 2.4 mm. Myopic macular neovascularization (MNV) was found in 41 of the 66 eyes with DLDs (62.1%). Patients with drusen in Zone 2 were significantly older than those in Zone 3 (80 ± 13 vs 64 ± 13 years; P < 0.001). Ultra-widefield images showed that peripheral DLDs were present in 4.9% of highly myopic eyes. The findings in eyes with DLDs may provide a basis for the evaluations of the natural progression of peripheral retinal changes in eyes with PM.

Distribution of Ocular Biometry and Intraocular Lens Power in Patients Undergoing Cataract Surgery in an Eye Camp in Northern Pakistan

Purpose: To report ocular biometric data of patients undergoing cataract surgery in an eye camp in a city of Northern area of Pakistan. Design: Cross-sectional descriptive study. Place and Duration of Study: A surgical eye camp was set up in the month of September 2022 for 6 days in a private hospital in Skardu. Methods: A total of 119 patients were selected with a non-probability consecutive sampling technique. Ocular biometry of permanent local residents with significant cataractswas included. Incomplete biometry data and coexisting diseases like corneal opacity, pterygium, and severe dry eye causing errors in biometry were excluded. Keratometry was done with an automated refractor-keratometer. Axial length was calculated with an A-scan (ultrasound contact method) and intraocular lens (IOL) power was calculated. Results: A total of 119 patients were selected for biometry among 3908 individuals visiting an eye camp. The mean axial length was 22.13 ± 1.25 SD mm. The mean keratometry readings (K1) was 43.28 ± 1.83 Diopter and (K2) 44.26 ± 1.67 D. The mean intraocular lens (IOL) power was 24.78 ± 3.43 D. The mean K readings were more in males as compared to females (p-value &lt;0.005). There was no significant difference in axial length and IOL power among genders. Conclusion: This study gives normative data on ocular biometric parameters of patients undergoing cataract surgery at high altitudes in Skardu, Pakistan. These biometric values can be used as reference values in the local population

Association of Refractive Errors with Axial Length and Anterior Chamber Depth in Different Age Groups

Purpose: To determine association of refractive errors with axial length and anterior chamber depth in different age groups. Study Design: Cross-sectional study. Place and Duration of Study: Ophthalmology Department of Dow University Hospital (Ojha campus),Dow International Medical College, Dow University of Health Sciences, Karachi, Pakistan from October 2020 to December 2020. Methods: Eighty-three individuals of different age groups ranging from 11-80 years were included in the study.Ocular measurements including refractive error, axial length, and anterior chamber depth were determined in all participants. The association of refractive error with anterior chamber depth and axial length was tested by using two independent sample t test, Mann-Whitney U test and ANOVA. Results: Among 83 individuals, males were 42.2% (n=35) and females were 57.8% (n=48). Most common type of refractive error was astigmatism which was found in 48.2% (n=40) participants. The overall average depth of anterior chamber (mm) and average axial length (mm) were 3.11±0.39 and 23.27±0.87 respectively. Mean differences in anterior chamber depth were statistically significant among different age groups . Statistically significant differences in mean axial length were found among different refractive errors . Conclusion: These results show a significant relation of different refractive errors with axial length and anterior chamber depth and it can be helpfulin explaining the risk factors of different ocular diseases as well asit can also be helpful in clinical and diagnostic purposes in ophthalmology.

Change in Axial Length and Astigmatism after Scleral Buckling in Patients of Rhegmatogenous Retinal Detachment

Purpose: To determine changes in axial length and corneal astigmatism caused by scleral buckling in patients of uncomplicated retinal detachment undergoing scleral buckling procedure. Study Design: Quasi-experimental design. Place and Duration of Study: Peshawar Medical College and Allied hospitals, Pakistan from December, 2020 to May, 2021. Methods: This study included60 patients of uncomplicated rhegmatogenous retinal detachment, recruited through consecutive sampling technique and managed with primary scleral buckling. After a detailed history and complete examination including A-scan and Keratometric readings, patients underwent scleral buckling procedure. Changes in axial length and corneal curvatureswere measured at 6 months follow up. Quantitative analysis was done using paired T test. Results: Mean age of the sample was 41.95±13.67 years. The sample consisted of 42 males and 18 females. Encircling Band was used in 46 patients, segmental circumferential tire was used in 58 patients in one or more quadrants depending on the extent of the retinal detachment. Two patients underwent additional surgeries. The pre-operative mean axial length (AL) was 23.44±1.51 mm and post-operative AL at 6 months was 24.25±1.61mm (p &lt; 0.05). The pre-operative and post-operative astigmatism were 1.08±0.43 and 1.75 ± 0.33 diopter respectively (p &lt; 0.05). Conclusion: Scleral buckling led to a significant increase in axial length and astigmatism over a 6-month period. These changes suggest that scleral buckling can alter the optical properties of the eye, potentially affecting visual acuity and requiring careful consideration of these factors in post-operative management.

Volume measurement of the vitrectomised eye and its applications in practice.

To estimate the vitreous cavity replacement volume after pars plana vitrectomy and analyze its correlation with axial length and refractive error. Observational cross-sectional study on 103 eyes undergoing vitrectomy. Fluid-air exchange was performed using a soft-tip cannula connected to a PVC tubing, the distal end of which opened into a 10-cc syringe without the plunger. The collected fluid was measured (and correction factors applied) to estimate the vitreous cavity volume. The mean axial length of 103 eyes was 23.43 ± 1.54 mm. The mean vitreous cavity volume was 4.46 ± 0.83 mL (2.8-8.1 mL). There was a strong positive correlation between axial length and vitreous volume, which was stronger for pseudophakic and aphakic groups than for phakic groups. Accurate assessment of vitreous cavity volume can enable precise quantification of tamponade, intravitreal drugs, and intravitreal chemotherapeutic agents. This will allow better surgical outcomes, decreased toxicity, and increased cost-effectiveness due to lesser wastage. To estimate the vitreous cavity replacement volume after pars plana vitrectomy and analyze its correlation with axial length and refractive error.

Visual and Refractive Outcomes after Phacoemulsification Cataract Surgery in Nanophthalmic Eyes.

Background/Objectives: The aim of this study was to report the visual and refractive outcomes of nanophthalmic eyes undergoing phacoemulsification at a tertiary cataract center. Methods: This is a prospective consecutive case series. Patients with an axial length of ≤20.5 mm who underwent phacoemulsification at a tertiary cataract center in Hong Kong were included. Eyes undergoing extracapsular cataract extraction or with a previous history of intraocular surgery including trabeculectomy were excluded. The outcome measures were the corrected distance visual acuity (CDVA) and refractive status at four months post-operation. Different intraocular lens formulas were used to compare the refractive outcomes. Results: Out of 22,847 cataract surgeries performed from May 2011 to March 2020, 14 eyes (0.06%) of 10 patients had axial lengths of ≤20.5 mm and underwent phacoemulsification. The mean axial length was 20.13 ± 0.44 mm. Out of these fourteen eyes, three (21%) had postoperative myopic shift with spherical equivalent refraction of more than or equal to 1D compared to the original target. Eleven eyes (79%) had postoperative refraction within 0.5D compared to the original target. Nine out of fourteen eyes (64%) had improvements in postoperative vision. There were no intraoperative complications. When comparing the Hoffer Q, Holladay 1, Holladay 2, Haigis and Hill-RBF 2.0 formulas, there was no significant difference in the absolute errors between the five formulas (p = 0.072). Conclusions: There was no significant difference in the mean absolute errors between the Hoffer Q, Holladay 1, Holladay 2, Haigis and Hill-RBF 2.0 formulas. Myopic shift was not uncommon, and more studies on intraocular lens (IOL) power calculation for short eyes are warranted.

Prevalence and associations of dome-shaped maculas. The Beijing Eye Study.

To explore the prevalence and associated factors of a dome-shaped macula (DSM) in a general population. Out of the population-based Beijing Eye Study cohort (n = 3468 participants), the investigation included all eyes with an axial length of ≥25 mm, and a randomized sample of eyes with an axial length of <25 mm. Using optical coherence tomographic (OCT) images, we examined presence and height of DSMs, defined as an inward convexity of the foveal retinal pigment epithelium (RPE)/Bruch's membrane (BM) line, detectable in at least two OCT scans perpendicularly orientated to each other. The study cohort consisted of 366 eyes (314 individuals) with a mean age of 63.7 ± 9.7 years and a mean axial length of 24.8 ± 2.1 mm (median: 25.1 mm; range: 18.96-30.88 mm). Prevalence of DSMs (found in 6/366 eyes; 1.9%; 95%CI: 1.0, 3.0) increased from 0/125 (0%) in non-myopic eyes to 1/152 (0.7%; 95%CI: 0.0, 2.0) in moderately myopic eyes, and to 6/83 (7.2%; 95%CI: 1.7, 12.7) in the highly myopic group. In multivariable analysis, higher DSM prevalence corelated with longer axial length (OR: 2.05; 95%CI: 1.36, 3.08; p < 0.001) and higher stage of myopic macular degeneration (OR: 1.08; 95%CI: 1.01, 1.16; p = 0.03). The mean maximal DSM height was 139 ± 107 μm (median: 100 μm; range: 25-350 μm). It was associated with higher stage of myopic macular degeneration (beta: 0.24; p < 0.001) and higher prevalence of macular BM defects (beta: 0.17; p < 0.001). None of the DSMs showed a serous retinal detachment or relative choroidal thickening. Higher DSM prevalence correlated non-linearly with longer axial length, with DSM height increasing with the presence of a BM defect. DSMs may be associated with an axial elongation-related BM overproduction in the fundus midperiphery in all meridians.

The Efficacy of Prismatic Bifocal Spectacle Lenses in Controlling Myopia Progression in Children.

Objective: Progression of myopia can lead to vision impairment and increase the risk of sight-threatening complications. Various strategies were described to control the progression of myopia, including the use of specialized spectacle. This retrospective study aimed to analyze the efficacy of prismatic bifocal spectacle lenses in controlling the progression of myopia in pediatric patients. Materials and Methods: Fifty-two eyes of 26 patients using prismatic bifocal spectacle lenses were retrospectively analyzed. Both eyes of each patient with a cycloplegic objective refraction measurement of ≥-2.00 D were included. Demographic data of the patients such as age and gender were investigated. The increase in objective spherical equivalent and axial length over the one year of single-vision spectacle use was compared with the increase observed one year after the prescription of bifocal prismatic spectacle. Results: The mean age of the patients was 11.65 ± 2.70 years. Sixteen patients were male, and 10 patients were female. The increase in mean spherical equivalent in eyes using single vision spectacles over one year was 1.25 ± 0.76 D, compared to 0.24 ± 0.14 D with prismatic bifocal spectacles, which was statistically significant). Similarly, the increase in mean axial length was 0.66 ± 0.31 mm with single vision spectacles and 0.014 ± 0.015 mm with bifocal spectacle, also statistically significant Multiple linear regression analysis revealed that baseline higher myopia and baseline shorter axial length were significantly associated with the treatment effect. Conclusion: The findings suggest that bifocal prismatic lenses have the potential to be an effective intervention for managing myopia in children, particularly those with high rates of progression. However, further research with larger sample sizes and longer follow-up periods is needed to fully understand the long-term impacts of this treatment approach.

Comparison of measurements and calculated lens power using three biometers: a Scheimpflug tomographer with partial coherence interferometry and two swept source optical coherence tomographers

PurposeTo compare the biometric measurements obtained from the Pentacam AXL Wave, IOLMaster 700, and ANTERION and calculate the recommended intraocular lens power using the Barrett Formulae.MethodsThis was a retrospective cross-sectional study of patients who underwent biometry using the Pentacam AXL Wave, IOLMaster 700, and ANTERION. Flat keratometry (K1), steep keratometry (K2), anterior chamber depth (ACD), and axial length (AL) from each device were measured and compared. These parameters were used to calculate the recommended IOL powers using the Barrett formula.ResultsThe study included 252 eyes of 153 patients. The IOLMaster had the highest acquisition rate among the two biometers. The Pentacam obtained the shortest mean AL, the IOLMaster measured the highest mean keratometry values, and the ANTERION measured the highest mean ACD. In terms of pairwise comparisons, keratometry and axial length were not significantly different between the Pentacam-IOLMaster and ANTERION-IOLMaster groups, while the rest of the pairwise comparisons were statistically significant. In nontoric and toric eyes, 35–45% of patients recommended the same sphere of IOL power. In another 30–40%, the Pentacam and ANTERION recommended an IOL power one step greater than that of the IOLMaster-derived data. 50% of the study population recommended the same toric-cylinder IOL power.ConclusionsThe Pentacam AXL Wave, IOLMaster 700, and ANTERION can reliably provide data for IOL power calculations; however, these data are not interchangeable. In nontoric and toric eyes, 35–45% of cases recommended the same sphere IOL power, and in another 30–40%, the Pentacam and ANTERION recommended one-step higher IOL power than the IOLMaster-derived data. In targeting emmetropia, selecting the first plus IOL power is advisable when using the Pentacam and ANTERION to approximate the IOL power calculations recommended by the IOLMaster 700.

Comparison of retinal nerve fiber thickness in emmetropes, myopes and hyperopes using optical coherence tomography

Aim of this study was to analyze retinal nerve fiber layer thickness by using spectral domen Optical Coherence Tomography (OCT) in different refractive status (emmetrops, myopes and hypermetrops).A cross-sectional study involved 150 patients aged 18-40, with and without refractive errors. Three groups (Emmetropic, Myopic, Hypermetropic) were tested using spectral domain OCT after pupil dilation, comparing RNFL thickness.In this study, 150 participants were categorized into three groups: emmetropia, myopia, and hypermetropia. The age group most represented was 21-25 years, comprising 35.3% of the sample. Of the total, 80 were male (53.3%), and 70 were female. Among males, 22 patients were emmetropia, myopia in 31 and hypermetropia in 27. The mean axial length for emmetropia was 23.54 ± 0.48 SD, myopia was 24.53 ± 0.48 and hypermetropia was 22.36 ± 1.11. Hypermetropia was further categorized into low-grade 22.49 ± 1.06 SD, moderate 22.26 ± 1.12 SD and high-grade 22.45 ± 1.00 based on axial length.Myopic individuals exhibited significant RNFL thinning, particularly in the inferior and superior quadrants, resembling early glaucoma-related changes. This has implications for glaucoma suspect evaluations.

Ocular biometric parameters in South-Indian children with myopia - A hospital-based retrospective descriptive analysis.

This study aims to profile the ocular biometric parameters in a large group of children of South-Indian ethnicity who visited our outpatient children's department and were diagnosed with myopia. Children <15 years old diagnosed with myopia (Jan 2022-Oct 2023) and who had ocular biometry readings recorded were included. Their demographics, axial length (AL), anterior chamber depth (ACD), spherical equivalent (SE), corneal radius of curvature (CR), and AL/CR ratio were analyzed. The study included 3728 myopic children; the mean age was 11.85 (4-15) years, and 52.8% were girls. Mean SE was -3.98 D. The mean (SD) AL, ACD, CR, and AL/CR ratio were 24.64 (1.32), 3.73 (0.40), 7.61 (0.27), and 3.24 (0.16), respectively. Female gender was associated with shorter AL, ACD, CR, and AL/CR ratios (P < 0.001) across all age groups. There was a significant increase in ACD with age in both sexes (P < 0.001). A 1-unit (mm) increase in AL was associated with an SE increase of -1.65 D (CL: -1.70 to -1.60). AL/CR ratio could explain 71% of the total variance in SE (P < 0.001). SE showed a mild correlation with age (rho = 0.14, P < 0.001) and ACD (rho = -0.03, P = 0.041) and a stronger correlation with AL (rho = -0.68, P < 0.001) and AL/CR (rho = -0.83, P < 0.001). In this hospital-based study, AL and AL/CR ratios strongly correlate with SE, and the AL/CR better explains the total variance in SE than AL alone in children with myopia.

Peripapillary Retinal Nerve Fiber Layer and Macular Ganglion Cell-Inner Plexiform Layer Parameters and Their Associated Factors in Cynomolgus Macaques.

The purpose of this study was to define the normal range of peripapillary retinal nerve fiber layer (pRNFL), macular ganglion cell layer (mGCL), and macular inner plexiform layer (mIPL) thickness in cynomolgus macaques, and explore their inter-relationship and correlation with age, refractive errors, and axial length (AL). In this cross-sectional study, we measured biometric and refractive parameters, and pRNFL/mGCL/mIPL thickness in 357 healthy cynomolgus macaques. Monkeys were divided into groups by age and spherical equivalent (SE). Correlation and regression analyses were used to explore the relationship between pRNFL and mGCL/mIPL thickness, and their correlation with the above parameters. The mean age, SE, and AL were 14.46 ± 6.70 years, -0.96 ± 3.23 diopters (D), and 18.39 ± 1.02 mm, respectively. The mean global pRNFL thickness was 95.06 ± 9.42 µm (range = 54-116 µm), with highest values in the inferior quadrant, followed by the superior, temporal, and nasal quadrants (P < 0.001). Temporal pRNFL thickness correlated positively with age (r = 0.218, P < 0.001) and AL (r = 0.364, P < 0.001), and negatively with SE (r = -0.270, P < 0.001). In other quadrants, pRNFL thickness correlated negatively with age and AL, but positively with SE. In the multivariable linear regression model, adjusted for sex and AL, age (β = -0.350, P < 0.001), and SE (β = 0.206, P < 0.001) showed significant associations with global pRNFL thickness. After adjusting for age, sex, SE, and AL, pRNFL thickness positively correlated with mGCL (β = 0.433, P < 0.001) and mIPL thickness (β = 0.465, P < 0.001). The pRNFL/mGCL/mIPL thickness distribution and relationship with age, AL, and SE in cynomolgus macaques were highly comparable to those in humans, suggesting that cynomolgus monkeys are valuable animal models in ophthalmic research.

An Analysis of Ocular Biometrics: A Comprehensive Retrospective Study in a Large Cohort of Pediatric Cataract Patients.

Objectives: This study aims to provide a comprehensive analysis of ocular biometric parameters in pediatric patients with cataracts to optimize surgical outcomes. By evaluating various biometric data, we seek to enhance the decision-making process for intraocular lens (IOL) placement, particularly with advanced technologies like femtosecond lasers. Methods: This retrospective comparative study included pediatric patients with cataracts who underwent ocular biometric measurements and cataract extraction with anterior vitrectomy at the Medical University of Vienna between January 2019 and December 2021. Parameters measured included corneal diameter (CD), axial length (AL), corneal thickness (CT) and flat and steep keratometry (Kf and Ks). The study explored the correlations between these parameters and IOL placement. Results: A total of 136 eyes from 68 pediatric patients were included in the study. Significant positive correlations were found between corneal diameter, age and AL. The mean CD was 11.4 mm, mean AL was 19.5 mm, CT was 581.2 ± 51.8 µm, Kf was 7.76 ± 0.55 mm and Ks 7.41 ± 0.59 mm, respectively. Older pediatric patients with larger corneal diameters and longer ALs were more likely to receive in-the-bag IOL implantation. Conversely, younger patients often required alternative IOL placements or remained aphakic. Our data indicated that over 95% of the study population and all patients aged one year and older had a corneal diameter of 10 mm or larger. Conclusions: Detailed ocular biometric analysis is crucial for optimizing both surgical outcomes and postoperative care in pediatric cataract patients. The positive correlations between CD, age and AL underline the importance of individualized surgical planning tailored to each patient's unique anatomical features. Additionally, our findings suggest that the use of a femtosecond laser is both feasible and safe for pediatric patients aged one year and older, potentially offering enhanced surgical precision and improved outcomes.

Temporal vascular arcade angle in fundus image was associated with the rate of spherical equivalent refractive error and axial length changes in myopia children with young school age

PurposeTo evaluate temporal vascular arcade angle and its influencing factors in myopic children. MethodsIt was a retrospective study, we reviewed the records of 119 patients aged 6–10 years with myopia (spherical equivalent refractive error (SER) ≤ -0.05D) in the third year of follow-up in Beijing Hyperopia Reserve Research. We measured temporal vascular arcade angles on the fundus photographs and measured 3-year rate of spherical equivalent(D/year) and axial length (AXL) changes(mm/year). ResultsMean age at initial visit was 7.71±1.20 years and mean SER was -1.32±1.09D. Children were divided into two groups according to the refractive status of children at baseline: Myopia onset group (SER>-0.50D at baseline) (n = 107) and Myopia progression group (SER≤-0.50D at baseline) (n = 12). The mean SER in Myopia progression group was much smaller than Myopia onset group (P < 0.001) and mean AXL in Myopia progression group was much longer than Myopia onset group (P = 0.042). AXL (r=-0.320, P < 0.001), SER change rate (r=-0.209, P = 0.022) and AXL change rate (r=-0.232, P = 0.011) were associated with temporal vascular arcade angle in all participants. In Myopia onset group, AXL (r=-0.317, P < 0.001) and AXL change rate (r=-0.190, P = 0.05) were associated with temporal vascular arcade angle. There were no parameters were associated with temporal vascular arcade angle (all P > 0.05) in Myopia progression group. Only AXL (r=-0.306, P = 0.018) was associated with temporal vascular arcade angle in girls while AXL (r=-0.370, P = 0.004), SER change rate (r=-0.317, P = 0.013) and AXL change rate (r=-0.365, P = 0.004) were all associated with the Angle in boys. ConclusionTemporal vascular arcade angle was associated with the rate of SER and AXL changes in myopia onset children, and showed gender differences. These may suggest that lamina cribrosa location has different influencing factors in different genders and different stages of myopia development. Due to the small number of people in Myopia progression group, large sample size studies are still needed in the future.

The Feasibility of Condylar Screws for Occipitocervical Fusion in Arabs: Computed Tomography-Based Morphometric Study.

Retrospective, cross-sectional study. Occipitocervical fusion is indicated for various conditions. Some techniques require placement of screws in the occipital condyle. The objective of this study was to analyze the morphometric features of the occipital condyle among Arabs. Computed tomography (CT)-based morphometric analysis of occipital condyles of 200 Arab skeletally mature patients (400 condyles) was done. Axial width of at least 8mm and coronal height of at least 6.5mm are the cutoff values for feasibility of condylar screw placement. The mean age of the patients was 48.0 ± 18.3years. Males were 53.5% (107) of the sample. The mean axial condylar width and length were 8.5 ± 1.5mm and 20.3 ± 2.6mm, respectively, while the mean axial screw angle was 35.9° ± 5.5° from midline. The mean sagittal condylar length and height were 16.1 ± 1.9mm and 8.8 ± 1.5mm, respectively. The mean condylar coronal height was 8.2 ± 1.4mm. Based on axial width and coronal height measurements, 150 (37.5%) condyles could safely fit a 3.5mm condylar screw. One hundred and four (55.9% female condyles) condyles cannot fit a screw in females, while 46 (21.5% male condyles) condyles cannot fit a screw in males. Condylar screw for occipitocervical fusion is feasible for the majority of Arabs in our sample; however, this applies to slightly less than half of the female condyles. Detailed preoperative radiological planning is critical to avoid complications related to occipital condyle screw placement.

Refractive Outcomes After Scleral Fixation of the Carlevale Intraocular Lens.

To assess the refractive predictability of the Carlevale sutureless scleral fixation intraocular lens (IOL) (Sole-ko IOL Division) power calculation. This retrospective, non-comparative, interventional case series included patients without a capsular support having undergone sutureless scleral fixation IOL implantation in two French hospitals between October 2019 and April 2022. IOL calculation was performed with the Barrett Universal II, Hoffer Q, Holladay 1, and SRK/T formulas with constant optimization to achieve a mean arithmetic prediction error equal to zero. The main outcomes were prediction error (PE) and its standard deviation (SD-PE), the median absolute error (MedAE), the mean absolute error (MAE), and the percentage of eyes with PE within ±0.50, ±1.00 and ±2.00 diopters (D) 6 months after surgery. Thirty eyes of 30 patients were included in the study. The mean age was 66.6 years, the mean axial length was 24.31 mm, and the mean keratometry was 43.07 D. SDPE ranged from 0.73 to 0.87 D depending on the formula. MedAE ranged from 0.38 to 0.61 D, and MAE from 0.52 to 0.68 D. Between 46.7% and 56.7% of eyes were within ±0.50 D, 76.7% and 90.0% were within ±1.00 D, and 96.7% were within ±2.00 D of target equivalent. No statistically significant difference was observed between the four formulas for any outcomes. This study confirmed that the design of the Carlevale sutureless scleral fixation IOL provides satisfactory refractive results. [J Refract Surg. 2024;40(8):e527-e532.].

Inner Retinal Microvasculature With Refraction in Juvenile Rhesus Monkeys.

To characterize inner retinal microvasculature of rhesus monkeys with a range of refractive errors using optical coherence tomography angiography. Refractive error was induced in right eyes of 18 rhesus monkeys. At 327 to 347days of age, axial length and spherical equivalent refraction (SER) were measured, and optical coherence tomography and optical coherence tomography angiography scans (Spectralis, Heidelberg) were collected. Magnification-corrected metrics included foveal avascular zone area and perfusion density, fractal dimension, and lacunarity of the superficial vascular complex (SVC) and deep vascular complex (DVC) in the central 1-mm diameter and 1.0- to 1.5-mm, 1.5- to 2.0-mm, and 2.0- to 2.5-mm annuli. Pearson correlations were used to explore relationships. The mean SER and axial length were 0.78 ± 4.02 D (-7.12 to +7.13 D) and 17.96 ± 1.08mm (16.41 to 19.93mm), respectively. The foveal avascular zone area and SVC perfusion density were correlated with retinal thickness for the central 1mm (P < 0.05). SVC perfusion density of 2.0- to 2.5-mm annulus decreased with increasing axial length (P < 0.001). SVC and DVC fractal dimensions of 2.0- to 2.5-mm were correlated with axial length and SER, and DVC lacunarity of 1.5- to 2.0-mm annulus was correlated with axial length (P < 0.05). Several inner retinal microvasculature parameters were associated with increasing axial length and SER in juvenile rhesus monkeys. These findings suggest that changes in retinal microvasculature could be indicators of refractive error development. In juvenile rhesus monkeys, increasing myopic refraction and axial length are associated with alterations in the inner retinal microvasculature, which may have implications in myopia-related changes in humans.

Axial length adjustment in eyes with silicone oil endotamponade reduces overestimation by a swept-source optical coherence tomography-based biometer.

To assess changes in ocular biometry of the phakic eye after pars-plana-vitrectomy (PPV) and silicone oil (SO) endotamponade in eyes with a retinal detachment. This retrospective, consecutive case series included 72 eyes of 72 patients who underwent PPV with 5000-centistokes SO endotamponade between July 2018 and June 2023. Pseudophakic eyes and eyes with a combined phacovitrectomy were excluded. Primary endpoints were keratometry values, anterior chamber depth (ACD), lens thickness (LT), horizontal corneal diameter (HCD), and axial length (AL) measured by swept-source optical coherence tomography-based biometry (IOLMaster 700) preoperatively and six weeks postoperatively. A recently described formula was used to adjust the AL (aAL) in eyes with SO endotamponade and a theoretical intraocular lens (IOL) calculation was performed. The mean age was 62.1 ± 8.3 years (range: 37-85). After PPV with SO fill, there was an increase in Kmean (0.19 ± 0.51D), while ACD (0.05 ± 0.13 mm), LT (0.03 ± 0.14 mm), and HCD (0.02 ± 0.24 mm) decreased. Preoperatively, the mean AL was 25.22 ± 1.78 mm, while postoperatively the AL was overestimated by 0.12 ± 0.42 mm on average (p = 0.04). By adjusting the AL, the mean difference could be reduced to -0.002 ± 0.41 mm. The aAL resulted in a difference in the refractive outcome in eyes with an AL > 25 mm of 0.34 ± 0.10D in the IOL calculation. While changes in biometry after PPV with SO endotamponade in the anterior segment are clinically less relevant, a considerable overestimation of AL with IOLMaster 700 was found. We recommend the use of a recently introduced formula for adjusting AL in eyes with SO, allowing overestimation to be minimised considerably.

Outcome of intraocular lens exchange for the management of myopic shift in pseudophakic children.

To evaluate the visual outcome of intraocular lens (IOL) exchange for the management of myopic shift in pseudophakic children. The medical records of children who underwent IOL exchange for myopic shift were examined. The preoperative data, operative details and the postoperative outcome were analyzed. Twenty-one eyes (16 patients) were identified. Mean age at cataract extraction was 20 ± 26 months (range, 2-84 months). Twelve patients (6 unilateral, 6 bilateral) had primary IOL implantation. Mean age at IOL exchange was 7.3 ± 3.2 years. Mean spherical equivalent (SE) at IOL exchange was -14 ± 5 D (range, -7 to -21 D): Mean SE at IOL exchange was -13.64 ± 4.99 D, -12 ± 1.53 D, and -15.5 ± 4.7 D in unilaterally pseudophakic cases (8 patients), in the eye that underwent unilateral IOL exchange (3 patients) in bilaterally pseudophakic cases, and in bilateral IOL exchange cases (5 patients), respectively. Mean axial length at IOL exchange was 24 ± 1.3 mm (range, 23 to 27 mm). Following IOL exchange, mean SE was reduced to -2 ± 1.8 D (range, -4 to +2.5 D). An average of three logMAR line improvement in the best-corrected visual acuity was observed in 12/16 eyes of patients for whom pre- and post-exchange visual acuity were available, while visual acuity remained unchanged in 4 eyes. Mean logMAR visual acuity improvement was 0.35 and 0.49 in unilateral and bilateral pseudophakic cases, respectively. IOL exchange is a safe procedure that should be considered to improve visual rehabilitation in pseudophakic patients with myopic shift.

Ocular biometry and anthropometric measurements in young myopes – A case–control study

Background: The prevalence of myopia in the 5–15-year age group in India has been 7.5% over the past four decades. While ocular growth and physical growth occur simultaneously during early life, the existence of a common regulatory system for both is still debated. Aims and Objectives: This study aims to analyze the ocular biometry and anthropometric values of young myopes and emmetropes aged 18–25 years. Materials and Methods: This case–control study involved a sample size of 86 participants. Corneal curvature was measured using keratometry, while A-scan ultrasonography was utilized to measure axial length, lens thickness, anterior chamber depth, and vitreous chamber depth. Results: The results indicated that there were no significant differences in ocular biometry and anthropometric values between the case and control groups, except for corneal thickness and axial length. The mean corneal thickness was found to be 549.64 μm in the case group and 566.05 μm in the control group, while the mean axial length was 24.70 mm in the case group and 23.41 mm in the control group. An increase in height was correlated with longer axial length in myopes. Conclusion: There was no difference in anthropometry and ocular biometry in emmetropes and myopes in the age group of 18–25 years of age. Myopes tend to have thinner corneas, which should be taken into consideration before performing refractive surgeries. The presence of thin corneas in individuals with myopia can result in inaccurately low measurements of intraocular pressure, potentially hampering the early detection of glaucoma within this high-risk demographic.