Retinal complications post posterior chamber phakic intraocular lens implantation at a tertiary eye hospital in the Eastern Province of Saudi Arabia.

PURPOSE: Phakic intraocular lenses treat higher degrees of myopia not possible previously with conventional refractive surgery. The aim of this study is to report the incidence and risk factors of retinal complications after posterior chamber PIOL implantation and assess the differences in biometric parameters between patients who developed such complications versus those who did not. METHODS: This retrospective study recruited 514 patients who underwent ICL implantation to correct myopia at a tertiary eye hospital center in the Eastern province of Saudi Arabia. Follow up period was at least one year. Medical records of the patients were reviewed to obtain the required data. Associations between respondents' characteristics and retinal complications were evaluated using the Chi-squared test. RESULTS: The mean (SD) age was 27.7 (± 6.5) years ranging from 18 to 47. Laser treatment was performed in 14 cases (2.7%). Retinal complications occurred in six cases (1.2%). The risk of retinal complication was significantly higher among patients with high axial length (OR = 1.3, 95% CI 1.2, 1.4) and patients with high pre-spherical equivalent before ICL (OR = 1.09, 95% CI 1.03, 1.4). CONCLUSION: Patients with higher axial length and higher pre-spherical equivalent before ICL implantation are at high risk of retinal complications.

Systematic evaluation of machine learning-enhanced trifocal IOL power selection for axial myopia cataract patients.

PURPOSE: This study aimed to evaluate and optimize intraocular lens (IOL) power selection for cataract patients with high axial myopia receiving trifocal IOLs. DESIGN: A multi-center, retrospective observational case series was conducted. Patients having an axial length ≥26 mm and undergoing cataract surgery with trifocal IOL implanted were studied. METHODS: Preoperative biometric and postoperative outcome data from 139 eyes were collected to train and test various machine learning (ML) models (support vector machine, linear regression, and stacking regressor) using five-fold cross-validation. The models' performance was further validated externally using data from 48 eyes enrolled from other hospitals. Performance of seven IOL calculation formulas (BUII, Kane, EVO, K6, DGS, Holladay I, and SRK/T) were examined with and without ML models. RESULTS: The results of cross-validation revealed improvements across all IOL calculation formulas, especially for K6 and Holladay I. The model increased the percentage of eyes with a prediction error (PE) within ±0.50 D from 71.94% to 79.14% for K6, and from 35.25% to 51.80% for Holladay I. In external validation involving 48 patients from other centers, six out of seven formulas demonstrated a reduction in the mean absolute error (MAE). K6's PE within ±0.50 D improved from 62.50% to 77.08%, and Holladay I from 16.67% to 58.33%. CONCLUSIONS: In this study, we conducted a comprehensive evaluation of seven IOL power calculation formulas in high axial myopia cases and explored the effectiveness of the Stacking Regressor model in augmenting their accuracy. Of these formulas, K6 and Holladay I exhibited the most significant improvements, suggesting that integrating ML may have varying levels of effectiveness across different formulas but holds substantial promise in improving the predictability of IOL power calculations in patients with long eyes.

Effect of capsular tension ring on the refractive outcomes of patients with extreme high axial myopia after phacoemulsification.

PURPOSE: The aim of the study is to evaluate the effect of capsular tension ring (CTR) implantation following cataract surgery on the refractive outcomes of patients with extreme high axial myopia. METHODS: Sixty eyes (with an axial length of ≥26 mm) were retrospectively reviewed and classified into two groups: CTR group (n = 30), which underwent CTR implantation following phacoemulsification, and control group (n = 30), which did not undergo CTR implantation. Intraocular lens (IOL) calculation was performed using Barrett Universal II (UII), Haigis, and SRK/T formulas. The refractive prediction error (PE) was calculated by subtracting the postoperative refraction from predicted refraction. The mean PE (MPE), mean absolute error (MAE), and percentages of eyes that had a PE of ±0.25, ±0.50, ±1.00, or ±2.00 diopters (D) were calculated and compared. RESULTS: No significant differences were observed in PE between the two groups. The Barrett UII formula revealed a lower AE in the CTR group than in the control group (p = 0.015) and a lower AE than the other two formulas (p = 0.0000) in both groups. The Barrett UII formula achieved the highest percentage of eyes with a PE of ±0.25 D (66.67%). CONCLUSIONS: The refractive outcomes were more accurate in eyes with CTR implantation than in those with routine phacoemulsification based on the Barrett UII formula. The Barrett UII formula was recommended as the appropriate formula when planning CTR implantation in high myopia.

Myopia, Sodium Chloride, and Vitreous Fluid Imbalance: A Nutritional Epidemiology Perspective.

Theories of myopia etiology based on near work and lack of outdoor exposure have had inconsistent support and have not prevented the rising prevalence of global myopia. New scientific theories in the cause and prevention of myopia are needed. Myopia prevalence is low in native people consuming traditional diets lacking in sodium chloride, and nutritional epidemiological evidence supports the association of rising myopia prevalence with dietary sodium intake. East Asian populations have among the highest rates of myopia associated with high dietary sodium. Similar associations of sodium and rising myopia prevalence were observed in the United States in the late 20th century. The present perspective synthesizes nutritional epidemiology evidence with pathophysiological concepts and proposes that axial myopia occurs from increased fluid retention in the vitreous of the eye, induced by dietary sodium chloride intake. Salt disturbs ionic permeability of retinal membranes, increases the osmotic gradient flow of fluid into the vitreous, and stretches ocular tissue during axial elongation. Based on the present nutritional epidemiology evidence, experimental research should investigate the effect of sodium chloride as the cause of myopia, and clinical research should test a very low-salt diet in myopia correction and prevention.

Bruch's membrane and Brücke's muscle in the pars plana region.

PURPOSE: To examine Bruch's membrane (BM) in association with the longitudinal part of the ciliary muscle (LPCM) in the pars plana region. METHODS: Using light microscopy, we histomorphometrically assessed BM and the LPCM in the pars plana region. RESULTS: The histomorphometric study included 51 eyes (51 patients; mean age: 60.8 ± 15.0 years; axial length: 26.0 ± 3.3 mm; range: 21.0-36.0 mm). The LPCM (total length: 4.60 ± 1.10 mm) ended 1.15 ± 0.56 mm anterior to the ora serrata. Within the pars plana region, the LPCM (length: 2.58 ± 0.98 mm) had direct contact with BM for 1.95 ± 0.99 mm (71.1 ± 18.4% of the BM undersurface), while a capillary layer was interposed between the BM and the LPCM for 0.70 ± 0.40 mm (29.0 ± 18.4%). In the pars plana region free of LPCM close to the ora serrata, the percentage of BM covered by the capillary layer was higher than in the pars plana region containing the LPCM (63.0 ± 42.1% vs. 29.0 ± 18.4%; p < 0.001). At the LPCM end, BM was in direct contact with a collagenous tissue from the LPCM and was focally thickened as compared to BM with an underlying capillary layer (9.5 ± 5.3 µm vs. 4.3 ± 1.2 µm; p < 0.001). CONCLUSIONS: The direct contact of BM with the LPCM in the pars plana in association with focal BM thickening at the LPCM end suggests an insertion of LPCM on the BM. Taking into account the biomechanical strength of BM, it may imply a functional unit of the LPCM with BM in the process of accommodation with a secondary movement of the posterior BM and tertiary thickening of the subfoveal choroidal space.

6PPD and its metabolite 6PPDQ induce different developmental toxicities and phenotypes in embryonic zebrafish.

The automobile tire antioxidant N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) and its quinone metabolite 6PPDQ have recently received much attention for their acute aquatic toxicity. The present study investigated the mechanistic developmental toxicity of 6PPD and 6PPDQ in embryonic zebrafish. Neither compound induced significant mortality but significantly decreased spontaneous embryo movement and heart rate. Both compounds induced malformations with different phenotypes; the 6PPD-exposed larvae manifested a myopia-like phenotype with a convex eyeball and fusion vessels, while the 6PPDQ-exposed embryonic zebrafish manifested enlarged intestine and blood-coagulated gut, activated neutrophils, and overexpressed enteric neurons. mRNA-Seq and quantitative real-time PCR assays showed that 6PPD- and 6PPDQ-induced distinct differential gene expression aligned with their toxic phenotype. 6PPD activated the retinoic acid metabolic gene cyp26a, but 6PPDQ activated adaptive cellular response to xenobiotics gene cyp1a. 6PPD suppressed the gene expression of the eye involved in retinoic acid metabolism, phototransduction, photoreceptor function and visual perception. In contrast, 6PPDQ perturbed genes involved in inward rectifier K+ and voltage-gated ion channels activities, K+ import across the plasma membrane, iron ion binding, and intestinal immune network for IgA production. The current study advances the present understanding the reason of why many fish species are so adversely impacted by 6PPD and 6PPDQ.

Myopic macular Bruch's membrane defects.

Purpose: To examine histologic characteristics of macular Bruchs membrane defects (BMD) in axially elongated eyes. Design: Histomorphometric study. Methods: Using light microscopy, we examined enucleated human globes for BMDs. Results: In 247 eyes, BMDs were detected in 15 (6.1%) eyes (axial length:27.0-36.0 mm), in 10 of them in the macular region. Prevalence and size of BMDs (mean:1.93 ± 1.62 mm; range:0.22mm-6.24 mm) correlated with longer axial length (OR:1.52; 95%CI:1.19,1.94; P = 0.001) and higher prevalence of scleral staphylomas (OR:16.3; 95%CI:2.67,99.3; P < 0.001). The BMDs were smaller than corresponding gaps in the retinal pigment epithelium (RPE) (1.93 ± 1.62 mm versus 2.61 mm ± 1.73 mm; P = 0.003), and larger than corresponding gaps in the inner nuclear layer (0.43 ± 0.76 mm; P = 0.008) and inner limiting membrane bridges (0.13 ± 0.33 mm; P = 0.001). Choriocapillaris thickness, BM thickness and RPE cell density did not vary (all P > 0.05) between the BDM border and adjacent areas. In the BMD, choriocapillaris and RPE were absent. The sclera was thinner in the BDM area than in adjacent areas (0.28 ± 0.19 mm versus 0.36 ± 0.13 mm; P = 0.006). Conclusions: BMDs as hallmarks of myopic macular degeneration are characterized by longer gaps in the RPE and smaller gaps in the outer nuclear layer and inner nuclear layer, by localized scleral thinning, and by a spatial association with scleral staphylomas. Thickness of the choriocapillaris and density of the RPE cell layer, both absent within the BDMs, do not vary between the BMD border and adjacent regions. The results suggest an association between BDMs and absolute scotomas, stretching of the adjacent retinal nerve fiver layer, and an axial elongation-associated stretching effect on BM as etiology of the BDMs.

Comparison of Optic Disc Ovality Index and Rotation Angle Measurements in Myopic Eyes Using Photography and OCT Based Techniques.

Purpose: To compare optic nerve head (ONH) ovality index and rotation angle measurements based on semi-automated delineation of the clinical ONH margin derived from photographs and automated BMO configuration derived from optical coherence tomography (OCT) images in healthy and glaucomatous eyes with high-, mild- and no axial myopia. Methods: One hundred seventy-five healthy and glaucomatous eyes of 146 study participants enrolled in the Diagnostic Innovations in Glaucoma Study (DIGS) with optic disc photographs and Spectralis OCT ONH scans acquired on the same day were stratified by level of axial myopia (non-myopic [n = 56, axial length (AL) <24 mm], mild-myopic [n = 58, AL 24-26 mm] and high-myopic [n = 32, AL >26 mm]. The clinical disc margin of each photograph was manually annotated, and semi-automated measurements were recorded of the ovality index and rotation angle based on a best-fit ellipse generated using ImageJ software. These semi-automated photograph-based measurements were compared to ovality index and rotation angle generated from custom automated BMO-based analysis using segmented OCT ONH volumes. R 2 values from linear mixed effects models were used to describe the associations between semi-automated, photograph-based and automated OCT-based measurements. Results: Average (95% CI) axial length was 23.3 (23.0, 23.3) mm, 24.8 (24.7, 25.0) mm and 26.8 (26.6, 27.0) mm in non-myopic, mild-myopic and high-myopic eyes, respectively (ANOVA, p ≤ 0.001 for all). The R 2 association (95% CI) between semi-automated photograph-based and automated OCT-based assessment of ONH OI for all eyes was [0.26 (0.16, 0.36); p < 0.001]. This association was weakest in non-myopic eyes [0.09 (0.01, 0.26); p = 0.02], followed by mild-myopic eyes [0.13 (0.02, 0.29); p = 0.004] and strongest in high-myopic eyes [0.40 (0.19, 0.60); p < 0.001]. No significant associations were found between photography- and OCT-based assessment of rotation angle with R 2 values ranging from 0.00 (0.00, 0.08) in non-myopic eyes to 0.03 (0.00, 0.21) in high-myopic eyes (all associations p ≥ 0.33). Conclusions: Agreement between photograph-based and automated OCT-based ONH morphology measurements is limited, suggesting that these methods cannot be used interchangeably for characterizing myopic changes in the ONH.

Comparison of the Accuracy of Intraoperative Aberrometry in Intraocular Lens Implantation Between Myopic Eyes with Emmetropia and Myopia Targets.

Purpose: To compare the accuracy of intraoperative aberrometry (IA) for predicting postoperative refraction between eyes with emmetropia and myopia targets. Patients and Methods: This retrospective analysis included patients with axial myopia (axial length ≥ 25.0 mm) who underwent uncomplicated phacoemulsification cataract surgery with IA to achieve emmetropia (plano to -0.5 D) or intentional myopia (-2.5 D to -5.0 D). Preoperative ocular biometry was performed in all eyes using an IOLMaster. Refractive prediction errors in IA were compared between eyes with emmetropia and myopia targets. Refractive prediction errors in IA for both groups were also compared with those predicted by intraocular lens power calculation formulas including the SRK/T, Holladay 1, Hoffer Q, Holladay 2, Haigis, and Barrett Universal II formulas. Results: Thirty-nine eyes of 39 patients with a target of emmetropia and 22 eyes of 22 patients with a target of intentional myopia were included in the final analysis. The mean numerical error was significantly different from zero (myopic trend) in myopia-targeted eyes (-0.37 ± 0.54 D, one-sample t-test, P = 0.004, 95% confidence interval: -0.61 to -0.14), while it was close to zero in emmetropia-targeted eyes. The mean absolute error was significantly smaller in emmetropia-targeted eyes (0.28 ± 0.27 D) than in myopia-targeted eyes (0.51 ± 0.41 D, P = 0.01). IA was revealed as the most accurate method for predicting postoperative refraction in eyes with emmetropia target, whereas Barrett Universal II formula was found to be the most accurate for eyes with myopia target. Conclusion: In patients with axial myopia, the performance of IA was altered when targeting intentional myopia compared with emmetropia. Myopic shift in the refractive outcome should be considered when IA is used to target myopia.

Efficacy of low-concentration atropine (0.01%) eye drops for prevention of axial myopic progression in premyopes.

PURPOSE: Low-concentration atropine (LCA; 0.01%) is known to reduce the progression of myopia in axial myopes. The purpose of this study was to understand the role of LCA in premyopic children in preventing progression. METHODS: A randomized case-control study of known premyopes was done between the use of LCA and no intervention. A total of 30 children were included in both groups. RESULTS: The mean age in the LCA group was 7.7 ± 2.1 years (5-12 years), and in the control group, it was 7.2 ± 1.9 years (4-12 years). The mean baseline progression per year in the LCA group (before starting the eye drops) was - 0.72 ± 0.3 D, and in the control group, it was - 0.69 ± 0.4 D. At the end of the first year, the mean progression in the LCA group was - 0.31 ± 0.3 D versus - 0.76 ± 0.4 D, and the axial length increase was 0.12 ± 0.1 mm in the LCA group and 0.21 ± 0.2 mm in the control group. At the end of the second year, the mean progression compared with the baseline in the LCA group was - 0.6 ± 0.3 D versus - 1.75 ± 0.4 D, and the axial length showed an increase from baseline in the LCA group by 0.21 ± 0.2 mm, and in the control group, the increase was 0.48 ± 0.2 mm in 2 years. CONCLUSION: Low-concentration eye drops (0.01%) work in preventing the progression of axial myopia in premyopic children.

Accuracy of Intraocular Lens Power Calculation Formulas in Myopic Eyes with Target Refractions of Emmetropia and Intentional Myopia.

PURPOSE: To compare the accuracy of the intraocular lens (IOL) power calculation formulas for predicting the postoperative refraction in eyes with a target of emmetropia or intentional myopia. PATIENTS AND METHODS: This is a retrospective study conducted at Kobe City Eye Hospital, Kobe, Japan. Fifty eyes of 50 patients with axial myopia who underwent uncomplicated phacoemulsification and single-type IOL implantation for a target of emmetropia (plano to -0.5 D) or intentional myopia (-2.0 D to -3.0 D) were selected. Preoperative ocular biometry was performed using IOLMaster700 in all eyes. Refractive prediction errors of 6 IOL formulas integrated into IOLMaster700 were compared between eyes with a target of emmetropia and intentional myopia. RESULTS: The mean numerical errors of SRK/T (Sanders, Retzlaff, and Kraft/theoretical), Holladay 1, Hoffer Q, and Holladay 2 significantly differed between the two groups (p < 0.001, p = 0.008, 0.02, and 0.007, respectively). The values for mean numerical errors in eyes with a target of intentional myopia were smaller, showing relatively myopic outcome, as compared with those in eyes with a target of emmetropia. In eyes with a target of emmetropia, the mean numerical errors of Holladay 1 (p < 0.001, 95% confidence interval [CI]: 0.32 to 0.63), Hoffer Q (p = 0.001, 95% CI: 0.12 to 0.42), and Barrett Universal II (p = 0.007, 95% CI: 0.06 to 0.35) were significantly different from zero (hyperopic trend). Furthermore, in eyes with a target of intentional myopia, the mean numerical error of SRK/T (p = 0.001, 95% CI: -0.61 to -0.17) and Holladay 2 (p = 0.023, 95% CI: -0.43 to -0.04) were significantly different from zero (myopic trend). CONCLUSION: In patients with axial myopia, some IOL formulas may show a myopic trend in the refractive outcome when targeting intentional myopia as compared to emmetropia.

Stopping the rise of myopia in Asia.

This review discusses the rapid rise of myopia among school-age children in East and Southeast Asia during the last 60 years. It describes the history, epidemiology, and presumed causes of myopia in Asia, but also in Europe and the United States. The recent myopia boom is attributed primarily to the educational pressure in Asian countries, which prompts children to read for long hours, often under poor lighting and on computer screens. This practice severely limits the time spent outdoors and reduces exposure to sunlight and far vision. As a consequence, the eyes grow longer and become myopic. In a breakthrough study in Taiwan, it has been found that by increasing the time spent outdoors, the incidence of new myopia cases was reduced to half when children were sent onto the schoolyard for at least 2 h daily. This protection is attributed to the light-induced retinal dopamine, which blocks the abnormal growth of the eyeball. Once myopia has set in, low-dose atropine and orthokeratology have shown positive results in slowing myopia progression. Also, prismatic bifocal lenses and specially designed multifocal soft contact lenses have recently been tested with promising results. Treatment, however, must be initiated early as the disease progresses once it has started, thereby enhancing the risk for severe visual impairment and ultimately blindness.

Complicaciones en cirugía de catarata por facoemulsificación en pacientes con miopía axial alta / Complications in cataract extraction by phacoemulsification in patients with high axial myopia

Objetivo: determinar la frecuencia de complicaciones en pacientes con miopía axial alta y catarata, a los que se les realizó extracción de catarata por facoemulsificación. Diseño del estudio: observacional descriptivo de frecuencia. Método: se incluyeron 107 ojos de pacientes con miopía axial alta, a los que se les realizó extracción de catarata por facoemulsificación más implante de LIO, operados en 2015. Se realizó una revisión de historias clínicas y descripciones quirúrgicas de los pacientes seleccionados y se evaluó la presentación de complicaciones con un seguimiento a un año después de la cirugía. Resultados: 2 ojos presentaron ruptura de cápsula posterior (1,8 %). Otros 2 ojos presentaron diálisis zonular (1,8 %) y en 3 ojos se evidenció pérdida de vítreo (2,7 %). Durante el primer año postoperatorio de seguimiento se observó desprendimiento de retina en 1 ojo (0,9 %). No se reportaron casos de luxación del LIO a cámara anterior. Conclusión: La frecuencia de complicaciones es similar a la reportada en la literatura mundial e inclusive más baja en algunas variables como la ruptura de capsula posterior y el desprendimiento de retina.

Background: Cataract extraction by phacoemulsifi cation plus intraocular lens (IOL) implant is the most used treatment against the main cause of reversible blindness in the world; the cataract. It is a very successful procedure due to its low frequency of complications and its high reproducibility. However, patients with high axial myopia do not behave in this way and tend to present more complications. Objective: to determine the frequency of complications in patients with high axial myopia and cataract, who underwent cataract extraction by phacoemulsifi cation. Study design: observational descriptive. Method: 107 eyes of patients with high axial myopia were included. All underwent cataract extraction by phacoemulsification plus IOL implantation, in 2015. A review of clinical histories and surgical descriptions of all patients was performed to determine the frequency of complications during a follow-up time of one year aft er surgery. Results: 2 eyes presented posterior capsule rupture (1.8%). Two other eyes presented zonular dialysis (1.8%) and 3 eyes had vitreous loss (2.7%). During the first postoperative year of follow-up, retinal detachment was observed in 1 eye (0.9%). No cases of IOL dislocation to the anterior chamber were reported. Conclusion: The frequency of complications in this population is similar to the one reported in other studies and even lower in some variables such as posterior capsule rupture and retinal detachment.

Effect of bilberry extract on slowing high-myopia progression in children: 2-year follow-up study.

AIM: To evaluate the effect of oral Difrarel on progression of high myopia in children and to study myopia course after its discontinuation. METHODS: A total of 64 highly myopic children were enrolled in this study. Patients were divided into two equal groups: group 1 was administered Difrarel for 1 year and stopped its intake for another year, and group 2 (control) did not take Difrarel. Refraction and axial length of the right eye of every subject were measured every 6 months in both groups. RESULTS: Each group had 32 eyes of 32 patients. The mean age was 9.34±2.27 years in group 1 and 9.33±2.2 years in group 2. Mean refraction and axial length at the start of the study were -10.78±2.6 D and 23.7±1.2 mm, respectively, in group 1, and -10.5±2.55 D and 23.9±1.4 mm in group 2. Refraction and axial length measurements every 6 months revealed statistically significant lower numbers in group 1 than group 2 after 1 year. After discontinuation of the drug, the difference between both groups remained significant. CONCLUSION: Oral Difrarel slowed axial elongation and stopped myopia progression in children with high myopia. The drug effect was consistent after its discontinuation for 1 year.

Prevalence of myopic retinopathy in rural Central India.

PURPOSE: The aim of this study was to determine the prevalence of myopic retinopathy (MR) in rural Central India. METHODS: The population-based Central India Eye and Medical Study included 4711 subjects (aged 30+ years). The participants underwent a detailed eye examination, including fundus photography. Myopic retinopathy was defined according to the Pathologic Myopia Study Group. RESULTS: Readable fundus photographs were available on 4561 (96.8%) subjects (8846 eyes). Myopic retinopathy was present in 15 (0.17 ± 0.04%; 95% confidence interval (CI):0.08%, 0.26%) eyes of 11 (0.24 ± 0.07%; 95%CI: 0.01, 0.04) individuals. Myopic retinopathy occurred only in eyes with an axial length of >26 mm. Eyes with MR had significantly larger optic discs than eyes without MR (3.69 ± 1.22 mm2 versus 2.52 ± 0.77 mm2 ; p < 0.001). In binary regression analysis, higher prevalence of MR was associated with longer axial length (p < 0.001; odds ratio (OR): 19.6; 95%CI: 4.6, 82.9), higher prevalence of open-angle glaucoma (p = 0.02; OR: 16.1; 95%CI: 1.51, 170), lower best-corrected visual acuity (expressed in logMAR) (=0.03; OR: 0.06; 95%CI: 0.004, 0.75) and female gender (p = 0.002). If level of education was added to the model, educational level was not significantly associated with MR (p = 0.17; OR: 0.53; 95%CI: 0.22, 1.31). If gender was dropped from the model, higher prevalence of MR was associated with lower educational level (p = 0.04; OR: 0.44; 95%CI: 0.20, 0.97). CONCLUSIONS: Prevalence of MR in rural Central India was low (11/4561 or 0.2%), and correlated with a 16 times higher risk of open-angle glaucoma, after adjusting for axial length and gender. If gender was excluded from the analysis, higher prevalence of MR was associated with lower educational level. This latter finding distinguishes adult MR from today's school children myopia which is strongly associated with higher educational level.

Acute angle closure in the setting of high axial myopia: A case report.

Acute angle closure is common in hyperopic eyes but uncommon in myopic eyes. Here, we report a case of angle closure attack in a 59-year-old female patient with high axial myopia. The patient presented without underlying medical history or drug history with marked congestion and progressively blurred vision in her right eye (RE) for 1 week. Initial intraocular pressure (IOP) was 40 mmHg in the RE and 19 mmHg in the left eye. Slit lamp examination revealed a very shallow anterior chamber in both eyes and marked corneal microcytic edema in the RE. Acute angle closure of the RE was diagnosed. Conservative IOP-lowering management followed by laser iridotomy was effective in managing acute high IOP crisis; however, early cataract extraction was necessary for long-term IOP control. Clinicians should be mindful of the possibility of acute angle closure even in highly axially myopic eyes.

Syndrome of myelinated retinal nerve fibres, myopia, amblyopia and strabismus in a Nigerian.

Myelinated retinal nerve fibres (MRNF) are rare congenital anomalies. They may present in a syndrome characterised by ipsilateral myelinated retinal nerve fibres, myopia and amblyopia. We report a case of this rare condition with unilateral extensive MRNF, axial myopia, amblyopia and strabismus in a Nigerian girl.

An examination of the baropathic nature of axial myopia.

An examination of how intraocular pressure distending forces on the posterior sclera are an important mechanism in the development and progression of axial myopia has been made. Papers were selected from the results of PubMed (143) and Science Direct (1,398) searches using the key word combinations of 'axial myopia' and 'intraocular pressure'. The main points include that the sclera is exposed to distending forces at all levels of physiological and pathological intraocular pressure. Reversible axial elongation is a common physiological response to elevated intraocular pressure in healthy eyes but more so in myopic eyes. Key variables, which appear to determine pathological (non-reversible) axial elongation include the thickness, rigidity and viscoelasticity of the posterior sclera and the associated increased susceptibility of it to distending forces. Intraocular pressure appears likely to have a greater role when it is above normal. Intraocular pressure elevations, which are not detected by clinical or experimental tonometry, may be significant contributors to axial elongation. Axial elongation can be pathological in myopic or myopically predisposed eyes, when elongation is not reversible. Axial elongation has also been associated with retinal defocus in both animals and humans, when thinning due to loss of scleral collagen and/or ground substance, which is driven by the retina, appears likely to be associated with increased scleral susceptibility to intraocular pressure. As myopia progresses, signs of retinal and choroidal stretching are an increasingly apparent consequence of the balloon-like expansion of the posterior sclera in response to intraocular pressure. Avoidance or moderation of activities which are known to elevate intraocular pressure may improve the prognosis for patients with genetic and/or environmental predisposition to myopic progression and may be an important consideration, even when other myopic control measures are being used.

Percaruncular single injection peribulbar anaesthesia in patients with axial myopia for phacoemulsification.

BACKGROUND: Myopia has been identified as a risk factor for globe perforation during regional anaesthesia for cataract surgery. We conducted this study to evaluate efficacy of single injection percaruncular peribulbar anaesthesia for phacoemulsification in patients with axial myopia. METHODS: Eighty patients with axial myopia received percaruncular peribulbar anaesthesia and were evaluated for incidence of major or minor complications. Also surgeon and patients' satisfaction and their comment on operative conditions were noted. RESULTS: Of the 80 patients 51 patients had posterior staphylomas. About three quarters of the patients developed adequate akinesia in 10 min. Remaining 25% received second injection with the same technique but with less volume after which the percent of patients with adequate akinesia rose to 91%. Adequate analgesia developed in almost all patients and only in one patient, intravenous analgesia was necessary to complete the operation. All operations were completed uneventfully. No perforations or penetrations were recorded and no other major complications were encountered. About 97% of the surgeons and 96% of the patients found the operative conditions satisfactory. CONCLUSION: Using single injection percaruncular peribulbar local anaesthesia for phacoemulsification in patients with axial myopia is an effective technique.