Volume 53 · Issue 01 · 2017

Looking back at the past 2016, the journal indicators of this journal ranked first among ophthalmology journals, which is the result of the joint efforts of all readers, authors and editors of this journal! We will continue to adhere to the tenet of respecting science, seeking truth and being pragmatic, and adhere to the review system of "three reviews and five determinations" to provide better academic content for the majority of ophthalmologists.

Blindness and visual impairment seriously affect people's physical health and quality of life, increase the burden on families and society, and are major public health problems. In 1999, the World Health Organization and the International Association for the Prevention of Blindness put forward the global strategic goal of "eliminating avoidable blindness by 2020". By 2020, avoidable blindness caused by cataract, trachoma, river blindness, childhood blindness, refractive errors and low vision should be eliminated worldwide. My Government is committed and actively involved in achieving this goal.

Over the past decade, great progress has been made in the clinical and epidemiological studies on refractive error and amblyopia in children with research findings published in international peer reviewed journals. This article reviews some of the essential publications so that the research findings could be learnt extensively, understood critically and objectively, and applied effectively to clinical practice. We aim to address the current limitations and shed light on clinical practice. (Chin J Ophthalmol, 2017, 53: 3-6)

Cataract is the leading blinding eye disease worldwide, and surgery is the only effective treatment at present. In recent years, with the increasing improvement of cataract extraction technology and the application of a variety of new functional IOL in clinic, patients have higher requirements for visual quality after cataract extraction, including postoperative naked eye vision and de-lens rate. Therefore, cataract extraction has entered the era of refractive surgery from the era of blindness prevention surgery.

To investigate biomechanical effects of central corneal thickness (CCT), and to explore the possible safe range for the tissue removal and percentage of tissue ablation (PTA) of small incision lenticule extraction (SMILE).

Clinical observational study. One hundred and eighty-seven cases (365 eyes) undergoing SMILE surgery were enrolled. Corneal hysteresis (CH) and corneal resistance factor (CRF) were measured before and after surgery by the ocular response analyzer (ORA). Linear regression of CH, CRF and CCT, and percentage of tissue ablation were calculated. The fifth order polynomial functions provided the closest fit to the data of ΔCH, ΔCRF and the thickness of tissue removal.

CH and CRF decreased by 20.7% and 33.0%, respectively, after SMILE, and statistically significant differences were found between preoperative and postoperative values (P<0.05). CH and CRF showed a positive correlation to CCT (r=0.483, P<0.05. r=0.507, P<0.05). The fifth order polynomial functions showed that ΔCH and ΔCRF increased with the increasing tissue removal. The variety rate of ΔCH and ΔCRF was lower after 50 μm to 140 μm of tissue removal, but was higher when the tissue removal was less than 50 μm and more than 140 μm. The variation trend was similar for PTA.

Corneal thickness has an effect on the corneal biomechanical properties, which decrease with the increase of tissue removal. It seems that the tissue removal of less than 140 μm and the PTA of less than 25% are safer in SMILE, and further investigations are needed. (Chin J Ophthalmol, 2017, 53:11-17)

To study the safety, efficacy and tolerability of the usage of 0.1% bromfenac sodium eye drops in small incision lenticule extraction (SMILE).

Prospective case control study. Three groups were observed, including 60 patients (60 eyes) undergoing SMILE for myopia. After surgery, 20 patients (20 eyes) were treated with 0.1% bromfenac sodium eye drops twice daily for 10 days, 20 patients (20 eyes) were treated with topical compound tobramycin eye drops 4 times daily for 10 days, and 20 patients (20 eyes) were treated with topical compound tobramycin eye drops 4 times daily for 3 days and 0.1% bromfenac sodium eye drops twice daily thereafter for 7 days. All of the patients were examined preoperatively and at 1 day, 10 days, 1 month and 3 months postoperatively, including visual acuity, intraocular pressure, topography and adverse reactions. The differences among the 3 groups were analyzed by the single factor analysis of variance.

There was no significant difference among the 3 groups in the uncorrected visual acuity at 10 days, 1 month and 3 months postoperatively (F=0.77, 0.30, 0.36. P=0.47, 0.75, 0.69) . The intraocular pressure in the dexamethasone group at 10 days, 1 month and 3 months postoperatively was higher than the other two groups with no significant difference (F=0.56, 0.98, 0.63. P=0.57, 0.38, 0.54) . The surface asymmetry index of patients was 0.33±0.10, 0.50±0.17 and 0.55±0.21 in the bromfenac sodium group, 0.33±0.08, 0.49±0.16 and 0.60±0.37 in the dexamethasone-bromfenac sodium group, and 0.31±0.12, 0.52±0.23 and 0.55±0.19 in the dexamethasone group; preoperatively and at 1 and 3 months, respectively. There was no significant difference among the 3 groups in the surface asymmetry index at 1 and 3 months postoperatively (F=0.09, 0.21. P=0.91, 0.81) . The surface regularity index of patients was 0.15±0.12, 0.34±0.18 and 0.40±0.18 in the bromfenac sodium group, 0.18±0.17, 0.33±0.26 and 0.33±0.26 in the dexamethasone-bromfenac sodium group, and 0.30±0.25, 0.41±0.28 and 0.34±0.29 in the dexamethasone group preoperatively and at 1 and 3 months, respectively. There was no significant difference among the 3 groups in the surface regularity index at 1 and 3 months postoperatively (F=0.74, 0.39. P= 0.48, 0.68) . In the bromfenac sodium group, one patient complained of binocular visual fatigue at 10 days, and one patient complained of dryness in one eye at 1 and 3 months.

Bromfenac sodium eye drops can be used to replace corticosteroids after SMILE procedure with high safety and good tolerance. Satisfactory recovery of visual acuity, intraocular pressure and ocular surface could be achieved. (Chin J Ophthalmol, 2017, 53: 18-22)

To evaluate the effects of side-cut angles on corneal biomechanical properties after femtosecond laser assisted-laser in situ keratomileusis (FS-LASIK).

In this clinical control study, 97 right eyes of 97 patients with myopia and myopic astigmatism undergoing FS-LASIK surgery were included randomly. Two types of side-cut angles were designed for the flap, 90° in 48 eyes and 130° in 49 eyes. The values of corneal resistance factor (CRF), cornea hysteresis (CH) and 37 biomechanical waveform parameters were measured using the ocular response analyzer preoperatively and at 1 and 3 months postoperatively. The comparison between the two groups at different follow-up time points was made with one-way analysis of variance, and the comparison among different follow-up time points in each group was performed with the repeated measures analysis of variance.

The mean CRF, CH, p area, h, dive1, dive2, w11 and w21 in both groups showed significant reduction at 1 month postoperatively (group 90°: CRF 10.49 vs. 6.85, CH 10.02 vs. 7.55, p1 area 3 537.54 vs. 1 918.07, h1 404.74 vs. 283.25, dive1 350.63 vs. 243.33, w11 10.50 vs. 7.58. group 130°: CRF 10.14 vs. 6.38, CH 9.93 vs. 7.13, p1 area 3 498.93 vs. 2 038.74, h1 411.93 vs. 304.49, dive1 352.51 vs. 265.12, w11 10.55 vs. 7.78. P<0.001) . The mean CRF, CH, p area, w, h, dive1 and dive2 in both groups showed significant reduction at 3 months postoperatively (group 90°: CRF 10.49 vs. 6.60, CH 10.02 vs. 7.65, p1 area 3537.54 vs. 2042.91, h1 404.74 vs. 307.77, dive1 350.63 vs. 263.33, w11 10.50 vs. 7.58. group 130°: CRF 10.14 vs. 6.45, CH 9.93 vs. 7.67, p1 area 3 498.93 vs. 2 187.97, h1 411.93 vs. 327.39, dive1 352.51 vs. 284.26, w11 10.55 vs. 7.61. P<0.001). The mean path in both groups showed significant increase at 1 and 3 months postoperatively (group 90°: path1 23.14 vs. 30.50 vs. 30.79. group 130°: path1 24.12 vs. 32.18 vs. 31.49. P<0.001). The mean aplhf, bindex, dive2 and path2 between both groups at 1 month postoperatively showed significant difference (F=8.609, 7.482, 5.238, 4.885, P<0.05). The mean path11 between both groups at 3 months postoperatively showed significant difference (F=6.160, P<0.05).

Corneal biomechanical properties significantly decrease after FS-LASIK, and different side-cut angles have some effect on corneal biomechanical properties after FS-LASIK. The corneal deformation is more stable after flap creation with an obtuse side-cut angle making the cornea under stress. Combined with waveform parameters of the ocular response analyzer, more subtle changes of corneal biomechanical properties can be found. (Chin J Ophthalmol, 2017, 53:23-32)

To investigate the effect of wearing long wavelength filter glasses on refractive development of children's hyperopia.

Case control study. Seventeen 5-7 years' old children with high hyperopia from optometry clinic of Eye and ENT Hospital Affiliated to Fudan University were enrolled in this research. The experiment design was self-control between right and left eye, 3 children were lost during two years' period of observation, all the children's hyperopic refraction were more than +6.00 D, cycloplegic by 1% atropine. All the children were required to wear long wavelength filter glasses for 6 hours after waking up, the rest of the time with the conventional glasses. Refraction, axis and red/green match point were tested before the intervention and 3, 6, 12, 18, 24 months, after the intervention.

After two years' intervention, hyperopia decreased, eye axis increased, the best corrected visual acuity increased both in experimental eyes and control eyes, but there were no statistically significant difference between the two groups at each time point. All children were with normal color vision, compared to the long-wavelength light, the hyperopic eyes were more sensitive to middle-wavelength light, no significant difference was found between two groups, red/green match points were 42.802±1.216 and 42.889±1.560 respectively. After wearing long wavelength filter, red/green match point were significant decreased in the experimental group in 6 months and 12 months time points (6 months: 0.995±0. 543vs. 0.104±0.143, t=3.04, P=0.005, 12 months: 1.096±0.392 vs. 0.17±0.248, t=2.725, P=0.008). The experiment eyes were more sensitive to long-wavelength light than the control eyes. But in later time, there was no significant difference between two groups.

Wearing long wavelength filter glasses two years has no effect on refractive development on children with high hyperopia, but it can cause short-term chromatic adaptation, making hyperopic eyes more sensitive to the long-wavelength light. (Chin J Ophthalmol, 2017, 53: 33-38)

To investigate macular retinal and choroidal thickness and blood flow change using optical coherence tomography angiography after posterior scleral reinforcement (PSR) surgery.

Prospective study. Twenty eyes of 10 patients with high myopia were enrolled in this open-label, single-treatment group and prospective study. Radial lines and Angio retina (3 mm×3 mm) module were performed for 20 eyes using Angio-vue optical coherence tomography (Avanti, Optovue) without pupil dilation, and best corrected visual acuity, spherical equivalent and axial length were compared before and 60 days after surgery. Retinal and choroidal thickness was measured in the fovea, 1 mm superior, 1 mm inferior, 1 mm nasal and 1 mm temporal to the fovea. Flow area, flow density and flow index were recorded using self-provided software in the superficial retina layer, deep retina layer, outer retina layer and choroid capillary layer, respectively. Statistical analysis was performed using SPSS 16.0. Data that followed normal distribution were compared with paired two-sample t-test, while others were compared with Wilcoxon signed rank test.

Of the patients participating in this preliminary study, the mean age was (35.5±4.2) years, and 50% were female. No significant difference was found between before and 60 days after PSR surgery in best corrected visual acuity (t=0.99, P=0.33), spherical equivalent (t=-1.89, P=0.07) and axial length (t=0.2, P=0.08). The retinal thickness in the fovea was thinner (Z=-2.58, P=0.01), while there was no significant difference in the 1 mm superior (t=0.44, P=0.67) , 1 mm inferior (t=0.05, P=0.96) , 1 mm nasal (Z=0.87, P=0.64) and 1 mm temporal (Z=-0.78, P=0.99) to the fovea. No significant difference was found in choroidal thickness (t=-0.12, P=0.87; t=-0.25, P=0.81. t=0.53, P=0.61; t=-0.91, P=0.38. t=1.2, P=0.25) before and after surgery. The postoperative flow density in the superficial and deep retinal layers (48.18±4.56% and 31.47±5.11%) was significantly increased (t=2.66, P=0.02; t=3.16, P=0.01) compared with pre-operation (33.82±4.33% and 14.29±3.89%). The postoperative flow index in the superficial and deep retina layers (0.044±0.005 and 0.025±0.005) was significantly increased (t=2.59, P=0.02. t=2.95, P=0.01) compared with pre-operation (0.028±0.004 and 0.010±0.003). The other flow measurements showed no significant difference.

Retinal thickness decreased, and flow density and index increased in the superficial and deep retinal layers after PSR surgery. This suggested blood flow improvement in the macular region after PSR surgery in high myopic eyes. (Chin J Ophthalmol, 2017, 53:39-45)

To study the ultrasonographic characteristics of pathologic myopia posterior staphyloma and the relation with retinoschisis.

Retrospective case series study. Eighty-seven eyes of 66 pathologic myopia patients with posterior staphyloma were included. Staphyloma morphology and anteroposterior axis of the eyeball were observed by B-scan ultrasonography. Optical coherence tomography was used to explore the retinoschisis.

Arc-shaped (10.35%), cone-shaped (22.99%), wedge-shaped (33.33%) and rectangle-shaped (33.33%) posterior staphylomas were found by B-scan ultrasonography. Posterior pole or macular retinoschisis was found by optical coherence tomography in 65 eyes (74.71%), 56 of which (86.15%) were observed to have a rough posterior ocular wall or membranoid attachment by ultrasonography. The anteroposterior axis of arc-shaped posterior staphyloma was shorter than that of staphylomas in the other shapes. Posterior staphyloma morphology was related to retinoschisis(r=0.385, 0.406. P<0.01). The retinoschisis was at the macula in 80.00% of cone-shaped posterior staphyloma, at the wedge-shaped corner in 75.00% of wedge-shaped posterior staphyloma and at the rectangle-shaped corner in 62.50% of rectangle-shaped posterior staphyloma.

It is hard to discover retinoschisis of pathologic myopia posterior staphyloma by ophthalmoscopy. Morphologic characters of posterior staphyloma and conditions of posterior eyewall can be showed directly under ultrasonographic examination. B-scan ultrasonography may provide a diagnostic basis for pathologic myopia retinoschisis. (Chin J Ophthalmol, 2017, 53: 46-52)

To investigate the effect of intravitreal injection of neural stem cells (NSC) induced from human umbilical cord mesenchymal stem cells, and to provide a theoretical basis for the clinical treatment of blood-retinal barrier damage due to diabetic retinopathy (DR).

Experimental study. Sixty male Sprague-Dawley rats were randomly divided into control group, DR group and NSC group. Diabetic rats were induced by injection of streptozotocin, and the control rats were injected with an equal volume of solvent. Three months after the establishment of diabetic models, the NSC group was injected with 2 μl of NSC in the right vitreous, and the DR group was injected with 2 μl of phosphate-buffered saline. One month later, all the rats were sacrificed. The retinal vessels and leakage were examined with flat-mounted retinas. Vascular permeability was quantified by analyzing albumin leakage using the Evans blue (EB) method. Retina was examined by hematoxylin and eosin staining.

Retinal blood vessels of the control rats were normal, with no EB leakage outside the vessels. The background fluorescence was enhanced and focal leakage and focal dilated vessels were detected in the DR group. In the NSC group, background fluorescence was enhanced slightly and EB leakage area decreased significantly compared with the DR group. The average EB in control group, DR group and NSC group were (9.91±1.53), (24.67±2.26) and (12.85±2.58)μg/g, The EB leakage in the NSC group decreased significantly compared with the DR group (q=9.748, P<0.05). Pathological hematoxylin and eosin staining showed that the retinal layer structure was normal and clear in the control group, the retina was thin, the cell arrangement was in disorder and the nucleus was swelling in the DR group, the status of the NSC group was between the other two groups.

Transferring human umbilical cord mesenchymal stem cells-induced NSC in vitro to diabetic rat models by intravitreal injection could reduce leakage of blood vessels and attenuate blood-retinal barrier breakdown induced by diabetes. (Chin J Ophthalmol, 2017, 53: 53-58)

The patient, a 36-year-old man, had blurred vision after being injured by boxing in his left eye on October 1, 2014. He did not see a doctor at that time. Seven days later, he found that the visual acuity of his left eye decreased significantly, and he was diagnosed as "choroidal rupture of his left eye" in another hospital (Figure 1), follow-up observation is recommended. Since then, he consciously fixed the black shadow in front of his left eye and visual deformation, and went to Shanxi Eye Hospital on November 8, 2014. The patient was healthy in the past and had a history of trauma in his right eye when he was young; Eye examination: right eye visual acuity 0.4, corrected visual acuity +0.50-2.00 DC x 90° =0.6; The visual acuity of the left eye was 0.12, which could not be improved by correction. IOP: 15 mmHg (1 mmHg =0.133 kPa) in the right eye and 13 mmHg in the left eye. No obvious abnormalities were observed in the anterior and posterior segments of the right eye; The anterior segment of the left eye was normal, and fundus examination showed a longitudinal crescent-shaped gray-white lesion in the macular area, with membrane-like reflex on the retinal surface with radial retinal folds. OCT examination showed a full-thickness macular hole in the left eye, with an aperture diameter of 237 μ m. The pigment epithelial layer was bulged in the macular area, local rupture, and membrane-like reflex on the retinal surface (Figure 2）。 Diagnosis: traumatic macular hole, epiretinal membrane, choroid rupture in left eye. 25G vitrectomy combined with epiretinal membrane and internal limiting membrane exfoliation and 14% C was performed in the left eye at Shanxi Eye Hospital on Nov. 21, 2014₃F₈Gas internal pressurization. One month after surgery, the visual acuity of the left eye was 0.3, and OCT examination showed that the macular hole was closed (Figure 3）。 Four months after surgery (April 1, 2015), during reexamination, he complained that the dark shadow and visual deformation in front of his left eye were more obvious than before, and the visual acuity of his left eye was 0.2. OCT examination showed that CNV in the macular area of his left eye and subretinal fluid were obvious (Figure 4）。 FFA examination showed: CNV in the macular area of the left eye (Figure 5）。 Approved by the Ethics Committee of Shanxi Eye Hospital, the patient signed the informed consent form and received intravitreous injection of ranibizumab injection 0.05 ml (containing ranibizumab 0.5 mg) in the left eye on April 6, 2015. After reexamination 1 month after injection, the visual acuity of the left eye was 0.5. OCT showed that the CNV in the macular area of the left eye was reduced, the subretinal fluid was absorbed but still existed, and the retinal neuroepithelium was edema between layers. The intraocular injection of 0.05 ml ranibizumab injection was readministered on 11 May 2015. After reexamination 4 months after the second injection (22 September 2015), the patient's visual acuity in the left eye was stable at 0.5. OCT examination showed that CNV and edema were significantly improved compared with those before injection. FFA examination showed that spotty and strip-shaped hyperfluorescence could be seen in the macular area of the left eye, and no obvious diffusion was seen in the late stage (Figure 6）。 On 30 June 2016, the patient was re-examined and the visual acuity of the left eye was 0.5. OCT examination showed that CNV lesions were stable with no obvious changes in activity (Figure 7）。 At present, the patient's visual acuity and fundus condition remain stable.

The patient was a 37-year-old male. On September 6, 2015, he went to the Department of Ophthalmology of Peking Union Medical College Hospital with no obvious trigger for fluttering dark shadows in front of his eye and visual acuity decrease for 3 days. The patient has been myopic in both eyes for more than 10 years. Prior health, no history of trauma, no family history of disease. Eye examination: visual acuity: right eye-4.75 DS corrected to 1.0, left eye-6.25 DS corrected to 0.5; Non-contact IOP: 17 mmHg (1 mmHg =0.133 kPa) in the right eye and 18 mmHg in the left eye. Physical examination of the right eye showed no obvious abnormalities. The conjunctiva of the left eye is not congested, the cornea is clear, the retrocorneal deposit (-), the anterior chamber is middle-deep, the aqueous humor flashes (-), the planktonic body (-), the iris is clear, the pupil is equal size and round, the diameter is 3 mm, the light reflection is slightly retarded, the lens is clear, and the vitreous body is mildly opaque. Fundus examination: leopard-like fundus, unclear optic disc boundary, red color, flake or flame-like bleeding on the surface and its periphery, thickening and tortuosity of the central retinal vein, scattered spots and flake-like bleeding of the retina, wedge-shaped white lesions with unclear boundaries can be seen next to the macula (Figure 1）。 FFA: Left ophthalmic artery filling was roughly normal (17 s), central vein filling was slow (venous filling completion time was 30 s), and the capillaries were mildly dilated. The temporal optic disc and posterior pole are scattered with fluorescence occlusion (Figure 2）。 OCT examination showed that there were multiple hyperreflective bands scattered between the inner plexiform layer (IPL) and the outer plexiform layer (OPL) in the nasal and paratemporal central regions of the fovea of the left eye (Figure 3）。 There was no abnormal appearance on FFA in the macular band-like hyperintensity area on OCT (Figure 2）。 Clinical diagnosis: acute paracentral acute middle maculopathy (PAMM) in left eye, central retinal vein occlusion (CRVO) non-ischemic type. Auxiliary examination: There were no obvious abnormalities in blood routine, liver and kidney function, antinuclear antibody, erythrocyte sedimentation rate, human leukocyte antigen B27 and anterolateral chest X-ray. He was given oral prednisone 60 mg once/d and ginkgo biloba leaves 19.2mg 3 times/d. The drug was regularly reduced, and the patient's symptoms gradually improved after regular outpatient review. After 3 months, the patient was reviewed in the ophthalmology clinic of Peking Union Medical College Hospital. The corrected visual acuity of his left eye recovered to 1.0, and the fundus examination was roughly normal (Figure 4), visual field examination revealed a local visual field defect around the nasal side (Figure 5), OCT showed that the local inner nuclear layer in the paracentral macula was thinner than before treatment (Figure 6）。

Optical coherence tomography angiography (OCTA) is a new technology of angiography in recent years. It has advantages of the optical coherence tomography (OCT), moreover, it can hierarchically observe the vascular morphology of the retina and choroid. By using the pseudo-color, abnormal vascular structure can be distinguished from normal vascular structure of the retina. With the fusion of the OCTA image and the regular OCT image, the structure and blood flow information can be obtained at the same time. This technology provides another method of examination for clinical ophthalmology, especially for the diagnosis of retinal diseases. This review will analyze and summarize the operating principle of OCTA, its application in ophthalmology, as well as its advantages and limitations. (Chin J Ophthalmol, 2017, 53: 65-72)

Recent studies found that peripapillary microcirculation was damaged in glaucoma patients, indicating that blood flow in the optic nerve head is important in the pathogenesis of glaucoma. Effects of different antiglaucoma drugs on optic papilla blood flow deserve attention. Prostaglandins is the first line antiglaucoma drug. The experimental and clinical studies on the potential of prostaglandins to modify the blood flow in the optic papilla and related mechanisms are reviewed in this article. Effects of ocular blood flow increase on the treatment of glaucoma require further investigations. (Chin J Ophthalmol, 2017, 53: 73-76)

The ciliary process is the main place of secretion of aqueous humor, located behind the angle of the chamber. Because the ciliary process is located behind the iris, it is a blind spot in routine ophthalmic examination. The whole picture of the ciliary process is rarely seen in daily clinical examination. In ophthalmic surgery, the ciliary process morphology of different diseases under different examination conditions can be seen by pressing the peripheral sclera or using video capture technology, anterior segment photography, Retcam photography, fundus angiography, UBM and endoscopic methods (Quintessence Picture 1）。