[Correlation between refraction and axial length in Albinos]. / Corrélation entre la réfraction et la longueur axiale du sujet Albinos.

PURPOSE: To investigate the relationship between refraction and ocular axial length in albinos. PATIENTS AND METHODS: A cross-sectional, analytical study was carried out from June to November 2021 at the Central Hospital of Yaounde (Cameroon), which included consenting albino subjects aged over 15years. All subjects underwent visual acuity testing, axial length measurements and objective refraction under cycloplegia. RESULTS: We included 51 albino subjects. The mean age was 26.06±9.47years, and the sex ratio was 0.5. Type 2 oculocutaneous albinism (OCA2) was predominant, representing 82.4% of cases. The mean uncorrected visual acuity was 0.93±0.25 logMAR, and the most common ametropia was myopic astigmatism (52.9%). The mean axial length was 24.65±2.54mm with extremes of 21.54 and 30.33mm. Eyes with myopia and myopic astigmatism had significantly longer axial lengths than those with hyperopic and mixed astigmatism. A strong, significant negative correlation (r=-0.93; P˂0.001) between the spherical component of the refraction and axial length was found. CONCLUSION: The spherical component of the refraction decreases significantly with increasing axial length in albinos.

Biometric and corneal characteristics in marfan syndrome with ectopia lentis.

PURPOSE: To describe the biometric and corneal characteristics of patients with Marfan Syndrome (MFS) and ectopia lentis. STUDY DESIGN: Observational, descriptive, prospective study. Subjects Individuals with MFS with ectopia lentis (EL). METHODS: Fourty-four eyes of 23 patients underwent Scheimpflug analysis using the Pentacam (Oculus, Wetzlar, Germany), axial length (AL) using the IOL master 700 (Carl Zeiss AG, Oberkochen, Germany), endothelial cell count (ECC) using the CEM-350 (NIDEK, Maihama, Japan) and corneal biomechanics evaluation with the Ocular Response Analyzer: ORA (Reichert Ophthalmic Instruments, Buffalo, New York, USA) and Corvis (Oculus, Wetzlar, Germany). Statistical analysis was performed using IBM SPSS Statistics 25.0. RESULTS: The direction of lens subluxation was most frequently supero-nasal 40.9% (18/44). Mean keratometry (Km) was 40.22±1.76 Diopters (D); mean corneal astigmatism was 1.68±0.83 D; total corneal aberrometric root mean square (RMS) was 2.237±0.795µm; higher-order aberrations (HOAs) RMS were 0.576±0.272µm; mean AL was 25.63±3.65mm; mean ECC was 3315±459cell/mm2; mean CBI was 0.13±0.24, mean TBI was 0.31±0.25, mean posterior elevation was 4.3±4.5µm; mean total corneal densitometry was 16.0±2.14 grayscale units (GSU). CONCLUSION: Increased axial length, flatter and thicker corneas with higher regular astigmatism, normal densitometry, normal corneal biomechanical indices and normal posterior elevation were observed in Marfan patients with EL.

Efficacy and safety of atropine in myopic children: A meta-analysis of randomized controlled trials.

PURPOSE: To evaluate the safety and efficacy of atropine for childhood myopia and further explore the optimal concentration of atropine, so as to provide more reference for clinical application. METHODS: PubMed, Embase, Cochrane Library and ClinicalTrials.gov were comprehensively searched for randomized controlled trials (RCTs) up to October 14, 2021. The efficacy outcomes were progression of spherical equivalent (SE) and axial length (AL). The safety outcomes included accommodation amplitude, pupil size and adverse effects. The meta-analysis was performed using Review Manager 5.3. RESULTS: Eighteen RCTs involving 3002 eyes were included. The results showed that at 6-36 months of treatment, atropine was effective in slowing the progression of myopia in children. At 12 months, the WMD of SE and AL of low-dose atropine was 0.25 diopters (D) and 0.1 millimeter (mm), moderate-dose atropine was 0.44 D and 0.16mm, high-dose atropine was 1.21 D and 0.82mm, respectively, compared with the control group. Similarly, at 24 months, low-dose atropine was 0.22 D and 0.14mm, moderate-dose atropine was 0.60 D, high-dose atropine was 0.66 D and 0.24mm, respectively. Interestingly, we also found that there was no significant difference in the effects of low-dose atropine on accommodation amplitude and photopic pupil size compared with the control group, and the rate of photophobia, allergy, blurred vision and other side effects was similar between the low-dose atropine group and the control group. In addition, atropine appears to be more effective in myopic children in China than in other countries. CONCLUSIONS: Atropine in various concentrations can effectively slow myopia progression in children, and its effect is dose-dependent, while low-dose atropine (0.01% atropine) appears to be safer.

Difference in the effect of orthokeratology on slowing teen myopia with different years of follow-up.

PURPOSE: To compare the effects of orthokeratology (OK) for early childhood myopia control and to contrast with clinical trial data published by various investigators. METHODS: The researchers studied papers in Pubmed, Embase, Clinicalkey and CNKI published before October 31, 2021, identified by searching for RCT (Randomized controlled trials) and cohort studies on the treatment of early childhood myopia with orthokeratology. The researchers extracted the mean deviation for axial elongation at each year of follow-up between the orthokeratology groups and control groups (myopic spectacles) and analyzed the results with stata 12.0 software. RESULTS: The meta-analysis included 4 RCTs and 9 cohort studies with 744 samples (OK group 362, control group 382), aged 6 to 17 years. There was evidence of heterogeneity (I2>50%) on axial elongation in the included data. At 1 year, 2 years, 3 years, 4 years, 5 years and 7 years of follow-up, the axial elongation figures were -0.15mm (95% [CI] (confidence interval), -0.16 to -0.14) in all studies, -0.28mm (95% [CI], -0.33 to -0.23) in all studies, -0.36mm (95% [CI], -0.45 to -0.27) in one study, -0.42mm (95% [CI], -0.52 to -0.32) in one study, -0.42mm (95% [CI], -0.77 to -0.07) in one study, -0.44mm (95% [CI], -0.65 to -0.23) in one study. The heterogeneity disappeared after dividing subgroups according to the length of follow-up. CONCLUSION: Compared with the control group, the first two years of orthokeratology can control axial elongation in children and effectively delay the development of myopia. However, this effect was not obvious after 2 years. It is recommended to prescribe orthokeratology for two years to obtain the best effect. The length of therapy must be taken into account when studying the effects of orthokeratology.

Changes of ocular biometry in eyes with posterior chamber phakic intraocular lens implantation.

OBJECTIVE: To evaluate changes in biometric variables and intraocular lens (IOL) calculation results after posterior chamber phakic IOL (PCPIOL) implantation. METHODS: This retrospective, observational study included 65 eyes of 38 patients who underwent PCPIOL (EVO Visian ICL) implantation for correction of myopia. Prior to and a minimum of one year (mean 14.9 months) after EVO Visian ICL implantation, biometric variables and IOL calculation results were compared. Optical biometry, including anterior chamber depth, axial length, flat, steep, and mean keratometry values and IOL calculation results for the Holladay 2, Hoffer Q, Haigis, and SRK/T formulas were measured using the IOLMaster 700 SWEPT Source OCT biometer. MAIN RESULTS: The mean anterior chamber depth decreased from 3.70±0.22mm to 3.34±0.39mm, the mean axial length increased from 26.61±1.61mm to 26.71±1.66mm, and the mean flat keratometry changed from 42.82±1.86 D to 42.73±1.83 D. These changes were statistically significant. The mean IOL power calculation also revealed a statistically significant decrease with all four formulas (ranging from 0.19 D to 0.30 D) after PCPIOL implantation. CONCLUSIONS: Biometric variables and IOL calculation results showed statistically significant changes one year after EVO Visian ICL implantations. However, IOL power calculations yielded a decrease of less than 0.50 D, inducing much less refractive deviation in the spectacle plane; and the change was primarily related to an increase in AL measurements. IOL power calculations in eyes with EVO Visian ICL in situ provided satisfactory and reliable results.

Effect of capsule tension ring on short-term refractive stabilization and visual performance in trifocal intraocular lens implantation.

PURPOSE: To provide refractive stability and increase visual performance with the use of a capsular tension ring in trifocal intraocular lens implantation. METHODS: This prospective randomized study was conducted in the Yeniyüzyil university ophthalmology department between February 2018 and September 2019. Eighty-six eyes of 43 patients with visual loss due to uncomplicated cataract in both eyes were randomly divided into two groups, A and B. The eyes in both groups underwent refractive lens exchange with implantation of the same design of trifocal IOL (plate haptic design). In group B, a capsular tension ring was inserted into the capsular bag before trifocal IOL implantation. Both groups were examined at 1day, 1week, 1month, and 3months postoperatively. At 3months after surgery, visual acuity, refractive errors and refractive prediction errors were analyzed and compared between groups A and B. RESULTS: The postoperative values in group A were spherical equivalent (mean±SD), 0.07±0.79 diopters (D); refractive sphere (mean±SD), 0.43±0.84 diopters (D); uncorrected distance acuity, 0.20±0.04 (logMAR); best-corrected distance acuity, 0±0.02 (logMAR). Group B values were 0.14±0.5 diopters (D), 0.61±0.45 diopters (D), 0.25±0.20 (logMAR), 0.01±0.04 (logMAR), respectively. There was no significant difference between the two groups with respect to the postoperative evaluation. CONCLUSION: The use of CTR in the implantation of the trifocal intraocular lens had no statistically significant impact on refractive stability.

Comparison of different formulas for intraocular lens power calculation using a new optical biometer.

PURPOSE: To evaluate and compare the predictability of different formulas for intraocular lens (IOL) power calculation using a new optical biometer (Aladdin). METHODS: This prospective cross-sectional study included 70 eyes of 70 patients who underwent uneventful phacoemulsification with IOL implantation. Preoperative IOL power calculations were performed using the Aladdin optical biometer. Postoperative actual refractive errors and errors predicted by the SRK/T, SRK II, Holladay 1, Hoffer Q and Haigis formulas were analyzed. The mean estimation error (EE), mean absolute estimation error (AEE) and the percentage of eyes within ± 0.50 and ± 1.00 D of the target refraction for each of five formulas were calculated and compared. This analysis was also repeated in three groups formed based on axial length (AL) (group 1: <22.5mm, group 2: 22.5-24 mm, group 3: >24 mm). RESULTS: In the overall study group, the smallest mean AEE was provided by the Holladay 1 formula, however there was no statistically significant difference in the mean AEE's predicted by the five formulas (P=0.34). The highest percentage of eyes within ± 0.50 and ± 1.00 D of the target refraction was also found by using Holladay 1 (71% and 97%). SRK/T provided smallest mean AEE for groups 1 (n=13) and 3 (n=16). In group 2 (n=41), the smallest mean AEE was obtained using Holladay 1. CONCLUSIONS: Based on the Aladdin biometric data used in our study, better results can be obtained using SRK/T formula in eyes with short or long AL. The Holladay 1 formula may be preferred in eyes with moderate AL.

[Factors linked to foveoschisis in high myopia]. / Étude des facteurs associés au fovéoschisis dans la myopie forte.

PURPOSE: To investigate the factors linked to foveoschisis in high myopia. METHODS: Retrospective study of 113 patients (200 eyes) with high myopia was conducted between January 2010 and June 2012. Subjects underwent a complete ophthalmic examination, spectral domain optical coherence tomography (OCT TOPCON 2000) and ocular echography. RESULTS: Of the 200 eyes, 22 (11%) had foveoschisis on OCT examination. On the basis of univariate analysis, five variables were associated with the pathologic changes, including spherical equivalent over 10 diopters (P=0.044), axial length over 30 mm (P=0.0028), macular chorioretinal atrophy (P=0.0009), posterior staphyloma (P=0.0007) and vitreoretinal interface factors (P=0.0002). In the multivariate analysis, three factors were independently associated with foveoschisis in high myopia: axial length (adjusted OR, 16.7; IC 95% 1.4-219.7, P=0.036), macular chorioretinal atrophy (adjusted OR, 13.2; IC 95%, 1.3-133.1, P=0.044), and vitreoretinal interface factors (adjusted OR, 36.1; IC 95%, 3.5-376.9, P=0.002). CONCLUSIONS: In our study, axial length, macular chorioretinal atrophy, and vitreoretinal interface factors were independently associated foveoschisis in highly myopic eyes.