Myopic choroidal neovascularization (MCNV) is one of the main reasons of vision loss in working population in Asia, which has brought economical and social-psychological burdens with high incidence in China, The precise pathogenesis of MCNV is unclear. Metamorphosia is the main reported symptom in these patients. The lesions were usually with smaller area, less leakage and relatively slow progression. Currently, intravitreal anti-vascular endothelial growth factor agents are now the established standard of care for MCNV, which was a major breakthrough in the treatment of MCNV achieving visual acuity improvement. Since the natural history, clinical features and therapy response of this disease is significant different from that in choroidal neovascularization secondary to age-related macular degeneration, the treatment dosing, frequency, retreatment criteria and the follow-up interval should been considerately. Facing the myopia boom in China, there is a need for the development of a precise definition and a more detailed classification for pathogenic myopia, optimize the outcome assessment and follow-up strategy, which should benefit to the further basically and clinical studies.
Objective To measure the choroidal thickness (CT) in myopic Chinese population and to analyze the correlation factors. Methods One hundred and thirty-four myopia patients (268 eyes) were recruited in this study, including 88 males and 46 females. Ages were from 18 to 38 years, with a mean of (21.5±4.3) years. The spherical equivalent power was -13.13 to -0.50 D, with a mean of (-5.17±2.15) D. The choroid thickness (CT) in macular region was measured by spectral-domain optical coherence tomography. The CT values at subfoveal (SFCT), 1 mm temporal (T1 mm), nasal (N1 mm), superior (S1 mm) and inferior (I1 mm) to the fovea and 3 mm temporal (T3 mm), nasal (T3 mm), superior (S3 mm) and inferior (I3 mm) to the fovea were recorded respectively. The correlation between SFCT and age, uncorrected vision (VAsc), best corrected visual acuity (BCVA), equivalent power, corneal curvature, central corneal thickness and axial length were analyzed. Vision results were converted into logarithm of minimal angle resolution (1ogMAR) so as to analyze statistically. Results The mean SFCT were （230.4±70.2） μm in this study. The SFCT was statistically different from the CT at S1 mm, I1 mm, T1 mm, N1 mm, S3 mm, T3 mm, N3 mm（t=4.279, 2.256, -7.498, 19.020, 7.286, -5.752, 37.921; P＜0.05） respectively, except the CT at I3 mm（t=0.695, P＞0.05）. There was a positive correlation between SFCT and equivalent power （r=0.251, P＜0.05）, corneal curvature （r=0.194, P＜0.05）. The SFCT was negatively correlated with 1ogMAR VAsc （r=-0.279, P＜0.05） and axial length （r=-0.367,P＜0v05）. No correlation was found between SFCT and age, 1ogMAR BCVA and central corneal thickness（r=-0.047, -0.091, -0.068; P＞0.05). Conclusions The SFCT in Chinese myopic subjects is （230.4±70.2） μm. SFCT is correlated with VAsc, equivalent power, corneal curvature and axial length. The axial length is the key factor affecting SFCT.
Retinal neovascularization is a complicated pathophysiological process as a result of imbalance between angiogenic and antiangiogenic factors. Correct understanding of the signaling pathways, exploring the critical factors involved in retinal angiogenesis, looking for new strategies by reconstructing the new vessels are helpful for knowing the mechanism of the occurrence and development of reitnal neovascularization, which would be good for preventing and treating retinal neovascularization diseases.
Objective lt;brgt;To evaluate the efficacy of arteriovenous sheathotomy on treatment of branch retinal vein occlusion (BRVO). lt;brgt; lt;brgt;Methods lt;brgt;Six consecutive patients (6 eyes) with BRVO underwent par plana vitrectomy, po lt;brgt;sterios vitreous cortex separation, arteriovenous sheathotomy for BRVO. The foll lt;brgt;owup period was within 3～12 months. Postoperative examinations included color fundus photography, fundus fluorescein angiography(FFA), optical coherence tomography(OCT) and multifocal electroretinography (mERG). lt;brgt; lt;brgt;Results lt;brgt;Increasing downstream blood flow in proximal past of compressed venule was promptly observed during the procedures of incision of the advential sheath of blood vessel, and separating and elevating the ateriole from the venule in all the operations in this series. Visual acuities improved postoperatively in 5 patients, and the best corrected visual acuity was 1.5. The examination of FFA showed obvious absorption of retinal hemorrhage, and leakage of dye was reduced, while large areas of capillary closure in retinas distal to the sheathotomy site were found 3 months after operation in 3 patients. OCT revealed disappearance or lightening of macular edema. mERG showed that the response amplitude of retina including the macular area was obviously higher after the operation. There was recurrent vitreous hemorrhage necessitating further surgery in one patient. lt;brgt; lt;brgt;Conclusion lt;brgt;The operation of arteriovenous sheathotomy for the treatment of BRVO is much beneficial to improve patient′s visual acuity, downstream blood flow and macular affections, although the improvement of retinal reperfusion of the retina is not obvious. lt;brgt; lt;brgt;(Chin J Ocul Fundus Dis,2002,18:6-9)
Pathological myopia can induce choroidal neovascularization (PM-CNV). The potential risk factors include ageing, long axial length of the eyeball, thinning of subfoveal choroidal thickness, fundus atrophy spot and lacquer crack. These factors may induce atrophy of retinal pigment epithelial cells (RPE) and hypoxia, resulting in vascular endothelial growth factors (VEGF) secretion by outer retina. The lesion type, location and activity of PM-CNV can be determined by fundus fluorescein angiography. The features of PM-CNV on optical coherence tomography include strong reflective area close to RPE with very small amount of subretinal fluid (active stage), surface strong reflection with signal attenuation area (scar stage) and flat lesion and chorioretinal atrophy (atrophy stage). Photodynamic therapy and intravitreal injection of anti-VEGF drugs are major treatments for PM-CNV, the latter is more commonly used now. However, more large randomized controlled studies are required to explore the treatment regimen (such as frequency, indications for repeated or termination of treatment) and the efficacy factors further.
Vascular endothelial growth factor (VEGF) is a multifunctional factor that promotes blood vessel formation and increases vascular permeability. Its abnormal elevation plays a key role in common retinal diseases such as wet age-related macular degeneration and diabetic macular edema. Anti-VEGF therapy can inhibit angiogenesis, reduce vascular leakage and edema, thereby delaying disease progression and stabilizing or improving vision. Currently, the clinical application of anti-VEGF drugs has achieved satisfactory therapeutic effects, but there are also issues such as high injection frequency, heavy economy burden, potential systemic side effects, and non-responsiveness. To address these issues, current research and development mainly aim on biosimilars, multi-target drugs, drug delivery systems, oral anti-VEGF drugs, and gene therapy. Some drugs have shown great potential and are expected to turn over a new leaf for anti-VEGF treatment in ophthalmology.