High Myopic Eyes Research Articles

Multimodal Deep Learning Classifier for Primary Open-angle Glaucoma Diagnosis Using Wide-field Optic Nerve Head Cube Scans in Eyes With and Without High Myopia.

An OCT-based multimodal deep learning classification model including texture information is introduced that outperforms single-modal models and multimodal models without texture information for glaucoma diagnosis in eyes with and without high myopia. To evaluate the diagnostic accuracy of a multimodal deep learning (DL) classifier using wide optical coherence tomography (OCT) optic nerve head cube scans in eyes with and without axial high myopia. 371 primary open-angle glaucoma (POAG) eyes and 86 healthy eyes, all without axial high myopia (axial length AL≤26mm) and 92 POAG eyes and 44 healthy eyes, all with axial high myopia (AL>26mm) were included. The multimodal DL classifier combined features of 3 individual VGG-16 models: 1) texture-based en face image, 2) retinal nerve fiber layer (RNFL) thickness map image and 3) confocal scanning laser ophthalmoscope (cSLO) image. Age, AL, and disc area adjusted area under the receiver operating curves (AUROC) were used to compare model accuracy. Adjusted AUROC for the multimodal DL model was 0.91 (95% CI = 0.87, 0.95). This value was significantly higher than the values of individual models (0.83 [0.79, 0.86] for texture based en face image; 0.84 [0.81, 0.87] for RNFL thickness map; and 0.68 [0.61, 0.74] for cSLO image; all P≤0.05). Using only highly myopic eyes, the multimodal DL model showed significantly higher diagnostic accuracy (0.89 [0.86 , 0.92]) compared to texture en face image (0.83 [0.78 , 0.85]), RNFL (0.85 [0.81 , 0.86]) and cSLO image models (0.69 [0.63 , 0.76]) (all P≤0.05). Combining OCT-based RNFL thickness maps with texture based en face images showed better ability to discriminate between healthy and POAG than thickness maps alone, particularly in high axial myopic eyes.

Association between Intraocular Pressure and Myopia Among Children Aged 7 to 16 years

Objectives: To investigate the association between high intraocular pressure and myopia in children and compare it to emmetropia, and to determine the relationship between elevated intraocular pressure and varying degrees of myopia. Study design and Setting: Comparative cross-sectional study was performed at the tertiary eye care hospital, Rawalpindi for six months from July 2021 to December 2021. Methodology: Patients with myopia of greater than 0.5Ds and emmetropes with visual acuity of 6/6 were included. All patients underwent visual acuity, cycloplegic refraction, and fundus examination in order to exclude the myopic patientswith other systemic and ocular disorders. Intraocular pressure and central corneal thickness were measured using a Tonopen tonometer and Pachymeter respectively.Data was entered on SPSS version 26 for analysis. Independent sample T-test and one-way ANOVA was utilized for inferential statistics. Results: A total of 218 subjects were included with a mean age of 11.38 ± 2.602 ranging from 7 to 16 years. Females 50.9% (n=111) were outnumbered by male participants 49.1% (n=107). The mean IOP in emmetropes was 13.35 ± 2.433 mmHg and in myopes was 15.22 ± 3 mmHg and there is a statistically significant mean difference between these groups (P-value <0.05). There is also a statistically significant mean difference between IOP and varying degrees of myopia, that is; low(13.46 ±2.797), moderate(16.62 ± 2.981), and high(19.215 ± 2.184). Conclusions: The IOP was higher in high and moderate myopic eyes as compared to emmetropes. Moreover, a strong association was found between myopia and elevated IOP in children.

Stereopsis after bilateral implantation of Toric intraocular lenses in high myopic cataract patients with astigmatism

PurposeTo evaluate near, intermediate, distance visual acuity and stereopsis after bilateral implantation of Toric intraocular lenses (IOLs) in high myopic patients with astigmatism. MethodsBilateral Toric or non-Toric IOL implantation (n ​= ​40 eyes each) was performed on high myopic cataract eyes with astigmatism. Best-corrected distance visual acuity (BCDVA), uncorrected intermediate visual acuity (UCIVA), uncorrected near visual acuity (UCNVA), residual refractive astigmatism (RRA), and near, intermediate, and distance stereoacuity were measured postoperatively at 7 days, 1 month, and 3 months. ResultsThe three-month postoperative BCDVA, UCIVA, and UCNVA of the Toric group were 0.08 ​± ​0.07, 0.30 ​± ​0.11, and 0.23 ​± ​0.14 LogMAR. All improved over the preoperative assessments (P ​< ​0.05). The RRA, UCIVA, and UCNVA were significantly better in the Toric group than the non-Toric group at all follow-up examinations (all P ​< ​0.05). At 3 months, the median near and intermediate stereoacuity of the Toric group were 100 (range 40 – 400) and 120 (range 50 – 400) arcsec, which were better than the non-Toric group (both P ​< ​0.05). Fine near stereopsis ≥100 arcsec was present in 65% of the Toric patients, and 50% had good intermediate stereopsis of ≥100 arcsec. However among non-Toric patients, only 15% and 5% achieved fine near and intermediate stereopsis. The postoperative BCDVA and best-corrected distance stereoacuity were similar in the two groups (P ​> ​0.05). ConclusionsIn bilateral high myopic cataract patients with astigmatism, Toric IOLs not only improved UCIVA, UCNVA, and RRA, but also enhanced near and intermediate stereopsis acuity.

Correlation between spherical equivalent and biometry parameters in adult Cynomolgus macaque

To characterize the distribution of refractive and ocular biometry parameters and analyze the effect factors of the refractive status in cynomolgus monkey colonies. A Population-based cross-sectional study was conducted in adult cynomolgus macaque colonies. Animals were anesthetized with Zoletil 50. Intraocular pressure was measured using the Icare tonometer. Cycloplegic refraction (three drops of 1% tropicamide) and corneal radius of curvature (CRC) were measured using an autorefractor. The spherical equivalent (SE) was calculated. Biometric measurements, including the anterior chamber depth (ACD), lens thickness (LT), and axial length (AL), were obtained by A-scan ultrasonography. The AL-to-CR ratio (AL/CRC) was calculated. Central corneal thickness (CCT) and choroidal thickness (ChT) were measured using the Heidelberg Spectralis HRA OCT. Multiple regression analysis was performed to explore the association between refraction and ocular biometry. Among 263 cynomolgus monkeys (aged 5-26 years), which consisted of 520 eyes, 29.42% had hyperopia, 27.12% had emmetropia, 33.27% had mild-to-moderate myopia and 10.19% had high myopia. The mean SE was -1.27±3.44 Diopters (D). The mean CRC, CCT, AL, and ChT was 5.70±0.22mm, 454.30±32.40μm, 18.76±0.89mm and 188.96±38.19μm, respectively. The LT was the thickest in the hyperopic eyes. CRC was the lowest, and CCT was the thickest in high myopic eyes. AL increased, while ChT decreased as SE decreased. For the SE variance, AL alone explained 40.5%; age, AL, and CRC together explained 57.5%. The refractive characteristics and biometry parameters of cynomolgus monkeys are highly comparable to those of humans. AL, CRC, and ChT showed the similar variation tendency in cynomolguses when compared to humans. Cynomolgus monkeys with naturally-occurring refractive errors may be a good animal model for refractive studies.

Comparisons of the protein expressions between high myopia and moderate myopia on the anterior corneal stroma in human.

To investigate the differentially expressed proteins (DEP) between high myopia and moderate myopia on the anterior corneal stroma. Tandem mass tag (TMT) quantitative proteomics was utilized to reveal proteins. DEPs were screened by the multiple change of more than 1.2 times or less than 0.83 and the P value < 0.05. The DEPs were functional annotated by Gene Ontology (GO) terms. Proteins and protein interaction (PPI) networks were conducted with String online tool. Parallel reaction monitoring (PRM) data processing was used to verify the TMT proteomics results. There are 36 DEPs between high myopia and moderate myopia on the anterior corneal stroma, of which 11 proteins are upregulated, 25 proteins are downregulated. The GO analysis demonstrated keratinocyte migration and structural constituent of cytoskeleton that are significantly changed with most of the proteins decreased in high myopic corneas. Keratin 16 (KRT16) and erythrocyte membrane protein band 4.1-like protein 4B are the only two proteins involved in both functions. The PPI analysis showed keratin type II cytoskeletal 6A (KRT6A) and KRT16 that have strong connections. Immunoglobulin lambda variable 8-61(IGLV8-61) and nicotinamide phosphoribosyl transferase (NAMPT) have consistent results with the TMT. The high myopic corneas have 36 DEPs compared to the moderate myopic corneas on the anterior corneal stroma. Keratinocyte migrations and structural constituent of cytoskeleton are weakened in high myopic corneas, which may partly account for the lower corneal biomechanics in high myopic eyes. The lower expressed KRT16 plays important roles in high myopic corneas.

Intraocular complement activation is related to retinal vascular and neuronal degeneration in myopic retinopathy.

To investigate the relationship between the intraocular levels of complement proteins and myopia-related retinal neuronal and vascular degeneration. Aqueous humour from 147 myopic patients, including 60 low-myopia and 87 high-myopia were collected during Implantable Collamer Lens implantation surgery. All participants received comprehensive ophthalmic examinations, including logMAR best corrected visual acuity, axial length measurement, fundus photography and ocular B-scan ultrasonography. The myopic eyes were further classified into simple myopia (SM, n = 78), myopic posterior staphyloma (PS, n = 39) and PS with myopic chorioretinal atrophy (PS + CA, n = 30). Retinal thickness and vascular density in the macula (6 mm × 6 mm) and optic nerve head (4.5 mm × 4.5 mm) were measured using Optical Coherence Tomography (OCT) and OCT angiography (OCTA). The levels of complement proteins including C1q, C3, C3b/iC3b, C4, CFB, CFH, C2, C4b, C5, C5a, CFD, MBL and CFI in the aqueous humour were measured using the Luminex Multiplexing system. The real-time RT-PCR was conducted to examine the expression of complement genes (C1q, C2, C3, C4, CFI and CFD) in the guinea pig model of long-term form deprivation-induced myopic retinal degeneration. OCTA showed that retinal neuronal thickness and vascular density in superficial and deep layers of the macular zone as well as vascular density in the optic nerve head were progressively decreased from SM to PS and PS + CA (p < 0.05). The aqueous humour levels of C1q, C3, C3b/iC3b, C4, CFB, CFH, C2, C4b, C5 and CFI were significantly higher in high-myopic eyes compared to those in low-myopic eyes. Further subgroup analysis revealed the highest levels of complement components/fragments in the PS + CA group. The intraocular levels of complement factors particularly C3b/iC3b and C4 were negatively correlated with macular zone deep layer retinal thickness and vascular density and optic nerve head vascular density. The expression of C2, C3 and C4 genes was significantly higher in guinea pig eyes with myopic retinal degeneration compared to control eyes. The intraocular classical pathway and alternative pathway of the complement system are partially activated in pathological myopia. Their activation is related to the degeneration of retinal neurons and the vasculature in the macula and the vasculature in the optic nerve head.

Outcomes of standalone ab interno trabeculotomy in the treatment of open-angle glaucoma in eyes with high myopia

BackgroundWe retrospectively evaluate the long-term efficacy and safety of trabeculotomy glaucoma surgery in treating open-angle glaucoma (OAG) in eyes with high myopia (HM).MethodsThis study included 20 eyes with HM (axial length ≥ 26.5 mm) and OAG; age, preoperative IOP (intraocular pressure), and sex-matched 20 non-HM eyes (axial length < 26.5 mm) served as controls. Each eye underwent standalone ab interno trabeculotomy using a Kahook dual blade. A follow-up examination was performed 36 months after surgery. The main outcome measure was the operative success rate (i.e., a ≥ 20% pre- to post-operative reduction in IOP with or without IOP-lowering medication). Kaplan–Meier analysis was employed as a measure of surgical success. The secondary outcome measures were postoperative IOP, the number of glaucoma medications, and postoperative complications.ResultsIOP and the number of glaucoma medications were statistically significantly reduced at all postoperative follow-up examinations. The Kaplan–Meier analysis demonstrated that the probability of postoperative success at 36 months was 45% and 65% for HM and non-HM eyes, respectively. In the HM group, the presence of pathological myopia was statistically significant risk factor for surgical failure. No critical postoperative complications were detected.ConclusionsIn our study, the long-term efficacy of ab interno trabeculotomy in HM eyes with OAG was inferior to that in non-HM eyes with OAG. Our findings suggest that surgical indications for trabeculotomy in HM should be determined based on the presence of pathological myopia.

Microvasculature and microstructure alteration in dry-type high myopia.

To investigate the alterations in the retinal vasculature and microstructure in dry-type high myopia. One hundred and eighty-nine dry-type high myopia eyes were classified into three groups. Group 1 consisted of 86 eyes with no myopic retinal degenerative lesion (C0). Group 2 consisted of 71 eyes with tessellated fundus (C1). Group 3 consisted of 32 eyes with diffuse chorioretinal atrophy (C2). Retinal vascular density and retinal thickness were measured with optical coherence tomography angiography. The scanning area was a 3 × 3 mm2 ring with the fovea of the macular. All data were analyzed with the SPSS 23.0 by one-way ANOVA test among comparison groups. Pearson's correlation analysis was used to determine the relations among measurements. Univariate linear regression showed a correlation between the vascular densities and retinal thicknesses. The microvessel density significantly decreased and significant thinning of the superior and temporal macular thickness in the C2 group. The vascular densities of macular decreased significantly with the increase of axial length (AL) and refractive diopter in the C2 group. The retinal thicknesses of the macular fovea increased significantly with the increase of vascular densities in the C0 group and C1 group. The impairment of retinal microstructure is more likely related to reduced oxygen and nutrients due to microvessel density decreases.

Complex hemodynamics of intervortex vein anastomoses in highly myopic eyes.

To analyze the complex pattern of filling of the intervortex vein (IVV) anastomoses through large trunks in highly myopic (HM) eyes based on indocyanine green angiographic (ICGA) videos. The medical records of 1060 consecutive HM eyes that had undergone ICGA were studied. IVV anastomoses were identified in the ICGA images, and the ICGA images and videos were analyzed comprehensively to characterize their hemodynamic features. Seven eyes with IVV anastomoses through large trunks were analyzed. In the ICGA videos of six eyes, laminar flow was observed in the IVV anastomotic vessels that started in the arterial phase in 2 eyes, with pulsatile fashion in 1 of them. The flow began in the early arteriovenous transition phase in 4 eyes. The laminar flow continued for a mean of 12.17±3.06 seconds, and the remaining section was gradually filled slower than the surrounding veins. The anastomotic trunk for the remaining 1 eye was too narrow to be analyzed. Four eyes had longitudinal ICGA records, and 2 had significant attenuation and narrowing of the anastomotic vessels. The very early filling of part of the IVV anastomoses suggests that arterio-venous anastomoses is involved in the IVV of HM eyes. However, this suggestion needs further study. There may be similar pathogenesis for IVV anastomoses either in thick or thin sclera.

Comparison of Conjunctival Sac Microbiome between Low and High Myopic Eyes

Microbial communities played a vital role in maintaining homeostasis of ocular surface. However, no studies explored the myopia-associated conjunctivamicrobiota changes until now. In this study, conjunctival sac swab specimens were collected from 12 eyes of low myopia (LM), and 14 eyes of high myopia (HM) patients. The V3-V4 region of the 16S rRNA gene was amplified and then sequenced. Statistical analysis was performed to investigate differences in the taxonomy and diversity between two groups. Compared to LM, higher Ocular Surface Disease Index (OSDI) scores were observed in HM group. The Shannon index of the HM was lower than that of the LM group (P = 0.017). Principle coordinate analysis and Partial Least Squares Discrimination Analysis showed distinct microbiome composition between two groups. At the phylum level, there were higher relative abundances of Proteobacteria (68.27% vs 38.51%) and lower abundances of Actinobacteria (3.71% vs 9.19%) in HM, compared to LM group (P = 0.031, 0.010, respectively). At the genus level, the abundances of Acinetobacter in HM (18.16%) were significantly higher than the LM (6.52%) group (P = 0.011). Actinobacteria levels were negatively correlated with the myopic spherical equivalent and OSDI scores. Moreover, positive correlations were found between Proteobacteria levels and OSDI scores, Acinetobacter levels were positively correlated with myopic spherical equivalent and OSDI scores. In conclusion, HM Patients have bacterial microbiota imbalance in the conjunctival sac, compared with LM patients. Proteobacteria, Actinobacteria, Acinetobacter may play roles in the HM associated ocular surface irritation.

Structure Function Relationships of Vessel Density and Retinal Nerve Fiber Layer Thickness in Early Glaucomatous Eyes With High Myopia.

The purpose of this study was to evaluate the structure function relationship of circumpapillary vessel density (cpVD) with visual field sensitivity (VFS) and compare its characteristics with circumpapillary retinal nerve fiber layer thickness (cpRNFLT) in early glaucomatous (EG) and normal eyes with and without high myopia (HM). Seventy-five EG (mean deviation > -6 dB) and 7 normal eyes with HM (axial length [AL] >26.5 mm) and 111 EG and 11 normal eyes without HM were enrolled in this retrospective cross-sectional study. All patients underwent circumpapillary optical coherence tomography (OCT) and OCT angiography (OCTA) scanning with the Cirrus HD-6000 with AngioPlex OCTA (Carl Zeiss Meditec, Dublin, CA, USA). Structure function correlations were determined by comparing global, superior, inferior, and Garway-Heath sectoral values for cpVD and cpRNFLT with its corresponding 24-2 and 10-2 VFS of Humphrey Visual Field (HFA) analyzer. CpVD showed no significant correlations with AL except for the nasal sector (P = 0.044), whereas cpRNFLT demonstrated significant positive association with AL in the global (P = 0.024), nasal (P = 0.020), and temporal (P < 0.001) sectors. In HM eyes, global and sectoral cpVD significantly correlated with corresponding VFS in all 24-2/10-2 VF sectors (all P < 0.05). CpVD-VFS correlation was significantly stronger than cpRNFLT-VFS in the nasal sector of HM eyes (P = 0.002) and temporal and inferior temporal sector of eyes without HM (P = 0.008 and P = 0.042, respectively). In EG eyes with HM, cpVD was less affected by AL in comparison to cpRNFLT and cpVD-VFS correlation was significant in all 24-2/10-2 VF sectors. AL-associated advantages of cpVD-VFS over cpRNFLT-VFS were observed.

Optimized design of surgical steps in pars plana vitrectomy for macular hole retinal detachment in pathological myopia decreases rate of iatrogenic retinal break and shortens length of operation

BackgroundTo investigate the effect of surgical steps optimization in pars plana vitrectomy (PPV) with internal limiting membrane (ILM) flap for macular hole retinal detachment (MHRD) in pathological myopia.MethodsA retrospective, consecutive, nonrandomized comparative study. High myopic eyes diagnosed with MHRD receiving PPV with ILM flap from March 2019 to June 2020 in Department of Ophthalmology, Xiangya Hospital, Central South University were included in the study. Patients were included into two groups based on different design of surgical steps. In the routine group, extension of posterior vitreous detachment (PVD) towards periphery was performed right after induction of PVD. In the experiment group, the retina was reattached with drainage of subretinal fluid through macular hole before peripheral vitreous was dealt with. Complete ophthalmic examinations were performed before and after surgery. The follow-up time was at least 6 months. The rate of iatrogenic retinal break and length of operation were compared between the two groups.ResultsThirty-one eyes from 31 patients were included in the study with 15 in the experiment group and 16 in the routine group. Demographics showed no statistically significant difference between the two groups. Post-op BCVA, rate of macular hole closure and rate of retinal reattachment were similar in the two groups. The rate of iatrogenic retinal break in the experiment group was significantly lower than that in the routine group (6.7% vs. 37.5%, P < 0.05). The average length of operation was 78.6 ± 18.8 min in the routine group and 64.0 ± 12.1 min in the experiment group (P < 0.05).ConclusionsOptimized design of surgical steps in PPV for MHRD could effectively decrease the rate of iatrogenic retinal tear and shorten the length of operation.

Longitudinal Changes of Bruch's Membrane Opening, Anterior Scleral Canal Opening, and Border Tissue in Experimental Juvenile High Myopia.

To investigate the relative positional changes between the Bruch's membrane opening (BMO) and the anterior scleral canal opening (ASCO), and border tissue configuration changes during experimental high myopia development in juvenile tree shrews. Juvenile tree shrews were assigned randomly to two groups: binocular normal vision (n = 9) and monocular -10 D lens treatment starting at 24 days of visual experience to induce high myopia in one eye while the other eye served as control (n = 12). Refractive and biometric measurements were obtained daily, and 48 radial optical coherence tomography B-scans through the center of the optic nerve head were obtained weekly for 6 weeks. ASCO and BMO were segmented manually after nonlinear distortion correction. Lens-treated eyes developed high degree of axial myopia (-9.76 ± 1.19 D), significantly different (P < 0.001) from normal (0.34 ± 0.97 D) and control eyes (0.39 ± 0.88 D). ASCO-BMO centroid offset gradually increased and became significantly larger in the experimental high myopia group compared with normal and control eyes (P < 0.0001) with an inferonasal directional preference. The border tissue showed a significantly higher tendency of change from internally to externally oblique configuration in the experimental high myopic eyes in four sectors: nasal, inferonasal, inferior, and inferotemporal (P < 0.005). During experimental high myopia development, progressive relative deformations of ASCO and BMO occur simultaneously with changes in border tissue configuration from internally to externally oblique in sectors that are close to the posterior pole (nasal in tree shrews). These asymmetric changes may contribute to pathologic optic nerve head remodeling and an increased risk of glaucoma later in life.

Posterior Scleral Indentation in long axial length eyes (axial length more than 34 mm) to assist in pars plana vitrectomy and internal limiting membrane peeling in full thickness macular holes.

To assess a novel surgical technique to perform macular surgery in high myopia eyes, with axial lengths more than 34 mm, where standard sized intravitreal surgical instruments cannot reach the retinal surface during pars plana vitrectomy for internal limiting membrane (ILM) peeling in myopic macular holes. Five eyes with axial length more than 34 mm were included in this study. A 7-mm Helvoston retractor was placed under tenon's capsule and guided along the eyeball until an elevation was noticed on the macular area. This elevation shortened the operating distance, temporarily, between the sclerotomy and retinal surface, enabling the use of standard size intraocular instruments. Preoperative vision and optical coherence tomography were compared with postoperative data and used as markers of anatomical and functional success. Vision improvement and anatomical closure of the macular hole with reattachment of the retina was achieved in all five eyes. No surgical complications associated with this surgical technique were noticed. Indenting the macular area from behind the eye globe with a 7-mm Helvoston retractor in a high myopic eye with axial length more than 34 mm during pars plana vitrectomy is safe and makes surgical procedures, such as ILM removal, easier.

Ten-year prevalence of rhegmatogenous retinal detachment in myopic eyes after posterior chamber phakic implantable collamer lens

To determine and compare the prevalence of rhegmatogenous retinal detachment (RRD) in myopic eyes operated of posterior chamber phakic implantable collamer lens (ICL) with a control group of nonoperated myopic eyes over 10 years of follow-up. Clinica Baviera, Madrid, Spain. Retrospective cohort study. There were 2 study cohorts: one with patients operated with ICL and a control group of nonoperated patients. The primary outcome of RRD was measured retrospectively, first through chart review of ICL-operated patients with at least 10 years of follow-up, then secondarily through telephone questionnaires and specialist verification for those with incomplete follow-up. Prevalence and incidence were calculated and compared, as well as their possible association with other risk factors. 58 operated patients completed follow-up in our clinic. A survey of 3849 more patients was conducted for a total of 252 operated with a mean spherical equivalent (SEQ) of -12.6 diopters (D) and 221 nonoperated with a mean SEQ of -10.5 D. 7 eyes developed an RRD in the operated vs 5 eyes among the nonoperated (prevalence 1.71% vs 1.25%, respectively, P = .773). The equivalence tests, the two one-sided test and the null hypothesis test between groups, were within the 0.02 limits, confirming the null hypothesis, and compared survival curves did not show significant differences ( P = .59). ICL implantation surgery for high myopia did not affect the prevalence of RRD in operated eyes compared with similar nonoperated eyes, in this long-term study.

A Modified Technique for Preventing Lens-Iris Diaphragm Retropulsion Syndrome in Vitrectomized Eyes during Phacoemulsification.

Lens-iris diaphragm retropulsion syndrome (LIDRS) is common in vitrectomized or high myopic eyes during phacoemulsification. We evaluated the results of a modified technique for cataract treatment using phacoemulsification in vitrectomized eyes. In this retrospective study, we enrolled thirty-four vitrectomized eyes treated with modified phacoemulsification (Modified Group) and nineteen vitrectomized eyes treated with routine phacoemulsification (Control Group). The modified technique comprised irrigation with a balanced salt solution underneath the pupil before phacoemulsification instrument entry, lens implantation and stromal hydration to stabilize the anterior chamber and equilibrate the pressure between the anterior chamber and posterior cavity. We compared the incidences of intra and postoperative complications and visual outcomes between modified and routine phacoemulsification. Pain, LIDRS and difficulty in stromal hydration were significantly more common in the Control Group than in the Modified Group (p < 0.05). There were no significant differences in the rates of posterior capsular rupture, iris trauma, lens dislocation, or posterior capsular opacification between the Modified and Control Groups (p > 0.05). However, there was no significant difference in visual acuity between the groups (p > 0.05). Complications such as loss of nuclear fragments into the vitreous cavity, cystoid macular edema, retina redetachment, suprachoroidal hemorrhage and vitreous hemorrhage did not occur either intra or postoperatively in any of our patients. Our modified technique prevents LIDRS and complications arising during cataract surgery in vitrectomized eyes. Aside from this, the results of modified and routine phacoemulsification are similar in vitrectomized eyes.

ANTERIOR SEGMENT OPTICAL COHERENCE TOMOGRAPHY IN DETERMINATION OF ENTRY SITE FOR VITRECTOMY IN HIGHLY MYOPIC EYES.

To evaluate the efficacy of anterior segment optical coherent tomography (AS OCT) in estimating the length of the pars plana and optimizing the sclerotomy entry site in vitrectomy for highly myopic eyes, facilitating membrane peeling. Twenty-three eyes with myopic traction maculopathy were studied. The pars plana was examined using two methods: preoperative AS OCT and intraoperative measurement. The distance from the limbus to the ora serrata in two groups was measured to compare differences in length. The actual length of the entry site from the limbus and forceps used were noted in all eyes studied. The mean axial length was 29.2 ± 2.3 mm for all 23 eyes. The average length between the limbus and ora serrata measured with AS OCT and intraoperative examination was 6,710 µ m (SD ± 459) and 6,671 µ m (SD ± 402), respectively, in the superotemporal region ( P > 0.05), and 6,340 µ m (SD ± 321) and 6,204 µ m (SD ± 402), respectively, in the superonasal region ( P >0.05). The mean length of the entry site from the limbus was 6.2 mm, and 28-mm forceps were used in 17 of 23 eyes (77%). The length of the pars plana varies depending on the axial length of the eye. Preoperative AS OCT enables accurate measurement of the pars plana in eyes with high myopia. AS OCT examination can help determine the optimal site for sclerotomy, allowing easier access to the macular region for membrane peeling in highly myopic eyes.

Optical Biometry versus Ultrasonic Biometry in Intraocular Lens Power Calculations in High Axial Myopia

Background: IOL implantation is now seen as a type of refractive surgery rather than merely being used to improve visual rehabilitation. In this context, accurate pre-operative biometric measurement is a crucial requirement. Aim of the work: comparing the refractive predictability of optical biometry versus applanation ultrasonic biometry in high axial myopic eyes undergoing cataract surgery. Patients and Methods: A total of 50 eyes from 50 patients with axial lengths greater than 26.5 mm and just cataract were analyzed in this study. In this study, patients were randomly assigned to one of two groups. Twenty-five patients were split evenly between the two groups, with group 1 using optical biometry and group 2 using applanation ultrasound. Results: Group 1 mean age was 53.8 ± 8.9 years since it was 51.8 ± 10.8 years in group 2. There were 7 males (28%) and 18 females (72%) in group 1 while there were 11 males (44%) and 14 females (56%) in group 2. There was no statistically significant variation in axial length between groups (p-value = 0.101).Statistically significant increased K1 and K2 among group 1 when compared with group 2 (p-value =0.003 and 0.001 respectively). Statistically significant (p-value = 0.015) increased anterior chamber depth (ACD) in group 1 when compared with group 2. Significant differences in postoperative refraction were seen across the groups (p 0.001) (SE values). Conclusion: Optical biometry offers significantly more precise IOL power prediction and refractive outcomes in cataract surgery for high axial myopia than applanation ultrasound biometry.

Choroidal Vascular Density Quantification in High Myopia with or without Choroidal Neovascularization Using Optical Coherence Tomography Angiography.

The aim of this study was to analyze choroidal vascular density alteration in high myopia with or without choroidal neovascularization by using optical coherence tomography angiography (OCTA). This was a cross-sectional, observational study that included 60 high-myopia eyes. All the participants had comprehensive ophthalmic assessments with visual acuity, intraocular pressure, slit lamp-assisted biomicroscopy, color fundus photography, axial length, optometry, and OCTA. Age, sex, and comorbidities were collected from their medical charts. Univariate and multiple analyses were made to compare the age, spherical equivalent, choroidal vascular density, gender, and choroidal thickness between normal and patients with choroidal neovascularization. 60 eyes with high myopia were included in our study, including 30 eyes with choroidal neovascularization and 30 eyes without choroidal neovascularization or other fundus pathology. The mean age of high myopic patients was older in the choroidal neovascularization group than in the normal group (48.43 ± 19.06 years vs. 28.83 ± 9.92 years, p < 0.01). The mean choroidal thickness of high myopic patients was thinner in the neovascularization group than in the normal group (68.81 ± 48.81 μm vs. 137.80 ± 66.33 μm, p < 0.01). The mean choroidal vascular density in the normal group was greater than in the choroidal neovascularization group (82.43 ± 8.73 vs. 67.54 ± 12.56, p < 0.01). There was no significant difference in spherical equivalent between the choroidal neovascularization group and the normal group (-10.56 ± 2.97D vs. -11.93 ± 3.38D, p = 0.11). Multivariate analysis showed that after adjusting for covariates, less choroidal vascular density and older age were independent factors associated with choroidal neovascularization in the high myopic eye. Decreased choroidal vascular density and older age played an important role in the development of choroidal neovascularization in high myopic eyes. OCTA may help us to identify the highly myopic patients that need to intervene.

Changes in retinal vascular bifurcation in eyes with myopia

ObjectiveTo evaluate the effect of myopia on retinal vascular bifurcation.MethodsA cross-sectional study that retrospectively analyzed the fundus photographs and clinical data of 493 people who participated in routine physical examinations in Huadong Sanatorium. One eye of each subject was included in the analysis. Retinal vascular bifurcation measurements were extracted by using a validated computer program. One-way ANOVA and analysis of covariance were performed to compare the measurements across high myopia, low to moderate myopia, and non-myopia groups.ResultsThe mean age was 41.83 ± 10.43 years and 63.49% were women. The mean spherical equivalent refraction (SER) was − 4.59 ± 3.07 D. Ninety-nine (20.08%) eyes met the definition of high myopia (SER ≤ -6.0 D), along with 234 (47.46%) low to moderate myopia (-6.0 D < SER <-0.5 D), and 160 (32.45%) non-myopia (SER ≥ -0.5 D). The differences in the arteriolar branching angle, venular branching coefficient, venular asymmetry ratio, venular angular asymmetry, and venular junctional exponent among the three groups remained significant (p < 0.05) after multivariate adjustment. Pairwise comparisons showed arteriolar branching angle and venular angular asymmetry in high myopia were significantly lower than low to moderate myopia (p < 0.001, p = 0.014 respectively) and non-myopia (p = 0.007, p = 0.048 respectively). Venular asymmetry ratio and venular branching coefficient in high myopia were significantly higher than low to moderate myopia (p = 0.029, p = 0.001 respectively) and non-myopia (p = 0.041, p = 0.043 respectively). There was a significant difference in venular junctional exponent between high myopia and low to moderate myopia (p = 0.031).ConclusionThe vascular bifurcation differs in dependence on the myopic refractive error and a significant increase in the difference can be observed in high myopic eyes.