Volume 55 · Issue 02 · 2019

This issue focuses on the research progress of myopia prevention and control. The responsible editorial committee responsible for the planning, composition and review of this issue is Professor Qu Jia.

Myopia prevention and control is an important health issue related to children and adolescents, general public physical fitness and national defense security. In 2018, General Secretary Xi Jinping gave instructions on students′ myopia. Ministry of Education and other seven ministries and commissions issued the Implementation Plan of the Myopia Prevention and Control for Children and Adolescents. As the myopia prevalence continues to develop into an urgent situation, myopia prevention and control has become a national strategy. In the battle fighting against prevalent myopia, medical and scientific researchers, as professionals, play a key role in guiding the effective implementation of the project and coordinating among five parties including government, schools, medical institutions, families and individual students. It is of great significance to effectively prevent and control myopia for children and adolescents and to achieve the overall goal of prevention and control. This article summarizes the potential effective methods in myopia prevention and control, hoping to provide useful reference and help for the national prevention and control work. (Chin J Ophthalmol, 2019, 55: 81-85)

It is essential to diagnose and assess children′s ametropia after cycloplegic refraction. The use of cyclopentolate 1% eyedrops in children is safe and effective for cycloplegic refraction. An accurate prescription should be based on the actual eye position and accommodation, as well as cycloplegic refraction in children. (Chin J Ophthalmol, 2019, 55: 86-88)

Over the past decade, breakthrough has been made on myopia progression control with a lot of evidence from clinical trials, but the effective clinical application of many of them remained immature. Though refraction clinics have been set up in many specialized hospitals offering spectacles to correct refractive error, there was few protocol or standard of treatment for reducing myopia progression. This commentary reviews the latest and essential publications and presents critical advice on applying the research findings to clinical practice. (Chin J Ophthalmol, 2019, 55: 89-92)

Standardizing the operation of glaucoma drainage valve implantation is an important measure to improve the quality of the operation and reduce and avoid related complications. According to the feedback of clinical practice, the Glaucoma Group of Ophthalmology Branch of Chinese Medical Association revised the Expert Consensus on the Operation Standards of Glaucoma Drainage Valve Implantation in China (2016), refined the specific steps of the operation, adopted corresponding improved technologies, and supplemented the postoperative care precautions and the identification and treatment of related complications. While further standardizing the operation, it emphasized the perioperative management, so as to improve the clinical skills and diagnosis and treatment level. (Chinese Journal of Ophthalmology,2019，55：93-97）

To get an orthokeratology lens fitting model according to the research of the optometry examination data, which can help to improve the work efficiency and increase the hitting rate of prescription.

The relationship between the basic optometry examination data and the effective optometry prescription was evaluated. We got 1 467 sets of data, including 80%(1 173) for training and 20%(294) for testing. The trail results were used for the 20% testing sets, and 100% completed sets for verification. With the contrast of accuracy, we got the influencing variables and the fitting model. Logistic regression and linear regression analysis were applied to the training set for building a fitting model, and the receiver operating characteristic curve (ROC curve) was drawn to determine the optimal threshold of the logistic regression model (1.0).The trail results are used for the 20% testing sets, 100% completed sets for verification. With the contrast of accuracy (ACC), we get the influencing variables and the fitting model.

Kf-FK and Ks-SK were selected as dependent variables. Through analysis of Stepwise regression, we found the influencing variables of Kf-FK were Kf(P=0.01), E_mean (P=0.027), and CYL(P<0.001), with FK=6.23+0.866kf-1.69 E_mean+0.16CYL, and the precision rate was 81%(r²=0.95). The influencing variables of Ks-SK were Ks (P<0.001), CYL (P=0.00), and E_mean (P<0.001), with SK=6.84+0.862ks-0.28E_mean-1.3CYL, and the precision rate was 80%(r²=0.93). By selecting the logistic method and decision tree analysis for glasses design, the influencing variables were KS (P<0.001)and CYL (P<0.001). The logistic function was Design=-45.7+0.82Ks+6.027CYL, and the precision rate was 87%.

The combination of AI and medical data can verify the expert experience and guide the optometrist to locate the prescription quickly and accurately. Try to break the traditional mode of fitting with wearing the orthokeratology lens shortly, and it is possible for us to position the prescription quickly through the calculation of a computer. (Chin J Ophthalmol, 2019, 55: 105-110)

To estimate the choroidal thickness (CT) in healthy children aged 2-6 years old and its relation to axial length, age and gender.

Cross-sectional study. CT was assessed using spectral domain optical coherence tomography (OCT) in 126 children aged 2 to 6 years. CT was measured at nine locations, including the subfovea and 1 mm and 3 mm nasal, temporal, superior and inferior to the fovea.

Mean subfoveal choroidal thickness (SFCT) was 331.56±62.03 μm. The choroid was thickest at the subfoveal and 1 mm temporal area, and thinner nasally compared to temporally, superiorly and inferiorly. No statistical significance of SFCT between male and female was noted. Stepwise multiple regression analysis revealed that axial length and age were associated significantly with SFCT ( P=0.00), while there was no detectable effect of sex on SFCT (P=0.94).

Choroidal thickness was negatively correlated to axial length and positively correlated to age in preschool children. The development of the choroid in early childhood offset the effect of the expansion of eyes. Gender played a minor role in the choroidal development in early childhood. (Chin J Ophthalmol, 2019, 55:111-114)

To investigate the influence of corneal biomechanical properties on opaque bubble layer (OBL) in small incision lenticule extraction (SMILE).

In this nested case control study, 20 patients (31 eyes) were enrolled in OBL group, while 51 patients (98 eyes) were included in non-OBL group. The parameters were obtained by Pentacam HR and Corvis ST examinations. Independent t test was used to analyze the difference of corneal biomechanical parameters between the two groups and multivariable logistics regression was applied to analysis the influence of corneal biomechanical properties on OBL.

This study enrolled 129 eyes in 71 cases including 30 males and 41 females, with a mean age of (22.50±5.18) years old. It has shown that the spherical equivalent (SE) [(-4.64±1.33) and (-5.78±1.61) D], central corneal thickness (CCT) [(572±29) and (550±32)μm], residual stromal thickness (RST)[(356±31) and (325±36 μm)], and lenticule thickness (LT) [(96±23) and (115±25) μm] were significantly different between OBL group and non-OBL group (t=3.58, -3.43, -5.68 and 3.64, respectively, P<0.05). There were significant differences in deflection amplitude at the first applanation and highest concavity (A1 DefA and HC DefA), deflection area at the highest concavity (HC DefArea), maximum deformation amplitude (DAmax), maximum deflection amplitude (DefAmax) and stiff parameter (SP) (108.85±13.77 and 100.19±14.13) between the two groups (t=-2.75, 2.41, 3.62, 4.09, 2.22 and -2.99, respectively, P<0.05). The OR and 95% confidence interval of SP in crude and adjusted logistics models were 1.04, (1.01-1.07) (P=0.005), and 1.01, (1.00-1.05) (P=0.426), respectively.

The occurrence of OBL could be influenced by various corneal biomechanical factors. The thicker CCT, thicker RST and the stiffer cornea may increase the risk for the occurrence of OBL. Fully acknowledgement on the relationship between corneal biomechanics and surgical outcomes and evaluation of the occurrence of OBL in SMILE surgery is of great importance for improving the safety and predictability of SMILE. (Chin J Ophthalmol, 2019, 55:115-121)

To compare the clinical outcomes between laser epithelial keratomileusis (LASEK) and transepithelial photorefractive keratectomy (TPRK) for treatment of myopia.

Case-control study. We reviewed a total of 90 right eyes that underwent either LASEK or TPRK, with 45 eyes in each group (aged between 18 and 40 years; 9 males and 16 females in the LASEK group, and 30 males and 15 females in the TPRK group) from 2015 to 2016 in Peking Union Medical College Hospital and Tangshan Eye Hospital. All the patients were followed up for 6 months postoperatively. Pain, uncorrected visual acuity (UCVA), and haze were measured at postoperative 3 days, 7 days, 1 month, 3 months and 6 months, and compared using an independent Student t-test between the two groups. Degree of haze, eye pain score, and visual acuity were compared by the Mann-Whitney U test.

At 3 days, the pain score was 1 (0,3) in the LASEK group versus 0 (0,1) in the TPRK group (Z=5.643, P=0.001). The UCVA was 4.80±0.10 in the LASEK group versus 4.97±0.07 in the TPRK group (Z=6.930, P=0.000) at 3 days, 4.98±0.08 in the LASEK group versus 5.05±0.06 in the TPRK group (Z=8.147, P=0.000) at 7 days, and 5.02±0.05 in the LASEK group versus 5.06±0.06 in the TPRK group (Z=2.381, P=0.017) at 1 month. The UCVA was also measured at 3 months, 5.07±0.07 versus 5.10±0.07 (Z=1.632, P=0.103), and at 6 months, 5.10±0.07 versus 5.11±0.07 (Z=0.798, P=0.425), respectively, with no statistical significance. The residual diopter was (0.17±0.19) D in the LASEK group versus (0.17±0.20) D in the TPRK group (Z=0.097, P=0.923) at 1 month, (0.03±0.11) D versus (0.07±0.14) D (Z=0.166, P=0.096) at 3 months, (0.07±0.13) D versus (0.07±0.14) D (Z=0.002, P=0.978) at 6 months, respectively. The surface regularity index (SRI) was 0.48±0.09 in the LASEK group and 0.46±0.06 in the TPRK group (t=0.88, P=0.37) at 1 month, and 0.49±0.07 in the LASEK group versus 0.47±0.06 in the TPRK group (t=1.53, P=0.132) at 3 months. Transient haze was documented in 1 eye in each group at 1 month (4.4%), with a maximum index of 0.5. No haze was observed in either group at 6 months.

TPRK has the advantages of faster early vision recovery and significantly less pain over LASEK. (Chin J Ophthalmol, 2019, 55: 122-126)

To investigate the clinical features, treatment distribution and transition of Mooren′s ulcer, and to observe the clinical outcomes and recurrence.

Retrospective series case study. Medical records of 125 patients (154 eyes) with Mooren′s ulcer treated between January 1996 and December 2015 at our hospital were retrospectively reviewed. Seventy-eight males and 47 females were include, with age of (47.6±14.3) years (range: 23-82 years) and median disease course of 6 months (range: 1-240 months). Follow-up occurred between 4.5 and 122 months and the ratio of males to females was 1.66∶1. All patients were divided into two groups: group 1996-2005 and group 2006-2015. Chi-square test was used to analyze the difference of treatment distribution between the two groups and recurrence rate relative to different risk factors. Clinical features and treatment outcomes of Mooren′s ulcers were observed simultaneously.

The lesion of the primary Mooren′s ulcer involved nasal, temporal, superior, inferior and all limbus in 48, 41, 13, 23 and 29 eyes, respectively. The numbers of eyes treated with medical therapy, LKP and amniotic membrane grafting were 6, 61 and 1 in group 1996, with recurrence rate of 1/6, 24.59% and 0 respectively. The numbers in group 2006 were 27, 38 and 14 with recurrence rate of 7.41%, 34.21% and 2/14, respectively. The differences of eyes underwent three different therapies were statistical significance between two groups (χ²=29.315, P=0.000), but the differences of total recurrence rate were not (χ²=0.149, P=0.699). Thirty-four patients (34 eyes) suffered ulcer recurrence, among which 23 eyes (67.65%) had recurrence within 12 months after treatment and 31 eyes (91.12%) were saved. Finally, 150 of 154 eyes (97.40%) were saved and 129 eyes (83.77%) retained vision better than 0.05.

Mooren′s ulcers were prone to occur in males and in patients older than 35 years. The lesion more often involved interpalpebral limbus. Lamellar keratoplasty was the most frequently used surgical intervention for primary Mooren′s ulcer with a recurrence rate of 28.28%. In recent 10 years, the percentage of patients treated with LKP decreased while percentage of medical treatment and amniotic membrane grafting went up obviously, and the total recurrence rate between two groups had no statitical differences. (Chin J Ophthalmol, 2019, 55:127-133)

To investigate the effect of deproteinized calf blood extract eye drops on early postoperative recovery in primary pterygium patients.

This is a prospective randomized controlled study. Patients diagnosed with primary pterygium in single eye at affiliated Xiamen Eye Center of Xiamen University during March 2016 to May 2016 were enrolled. After Pterygium excision with autologous conjunctival transplantation, patients were randomly assigned into four groups by a random number table, treated with anti-inflammaroty drugs only (control group) or combined with the following agents: deproteinized calf blood extract eye drops (DCBE group), carboxymethylcellulose sodium eye drops (CMC group), and recombinant human epidermal growth factor eye drops (rEGF group). Short-form McGill pain questionnaire, slit lamp and corneal fluorescein sodium staining, non-contact intraocular pressure, uncorrected visual acuity (UCVA) and best corrected visual acquity (BCVA) as well as redness score of bulbar conjunctiva were performed before surgery (d0) and on day 1 (d1), day 2 (d2), day 3 (d3), day 7 (d7) and day 14 (d14) after surgery.

One hundred and fourteen patients including 43 males and 71 females, aged (48.9±12.5) years, were eventually included in this study. The McGill scores gradually decreased after surgery in all groups. On d2, the McGill score in DCBE group, control group, CMC group and rEGF group was (1.42±0.67), (2.21±0.88), (1.93±1.08) and (1.77±1.18), respectively; On d3, the score was (1.32±0.54), (1.93±0.72), (1.79±0.87) and (1.52±0.77), respectively. On d2 and d3, statistical difference was recorded among groups (d2, F=3.43, P=0.019; d3, F=4.047, P=0.009), and the McGill score of DCBE group was significantly lower than that of CMC group (d2, P=0.047, d3, P=0.017). On d2, the percentage of corneal epithelium defect in DCBE group, control group, CMC group and rEGF group was 8.6%±1.9%, 11.7%±1.7%, 11.5%±1.9% and 10.4%±1.8%, respectively; On d3, the percentage was 4.5%±2.2%, 9.2%±2.4%, 7.4%±2.5% and 5.9%±2.3%, respectively. On d2 and d3, statistical difference of corneal epithelium defect percentage was recorded among groups (d2, F=17.17, P<0.001; d3, F=21.4, P<0.001). On d2, the percentage of corneal epithelium defect in DCBE group was significantly lower than the other three groups (P<0.01); On d3, the percentage of corneal epithelium defect in DCBE group was significantly lower than control group and CMC group (P<0.001), while no difference was found between DCBE group and rEGF group (P>0.05). However, no statistical differences were recorded in the number of patients with vision improvement among the groups (P>0.05). The intraocular pressure remained stable. No differences in the conjunctival redness score were found among the groups after surgery (P>0.05).

Our data demonstrated the efficacy of deproteinized calf blood extract eye drops on the postoperative management in patients with primary patients, with faster pain relief and promoted epithelium recovery. (Chin J Ophthalmol, 2019, 55:134-140)

To explore the changes of microcirculation of the bulbar conjunctiva after wearing the contact lens and the relationship between contact lens discomfort and bulbar conjunctiva microcirculation.

Prospective cohort study. The postgraduate students from School of Ophthalmology & Optometry and School of Biomedical Engineering of Wenzhou Medical University were included in this prospective cohort study. The subjects wore soft contact lenses, and the right eye was selected as the experimental eye. The ocular surface disease index (OSDI) questionnaire, Schirmer I and tear break-up time tests were completed before and after wearing the contact lens, and the conjunctival blood flow velocity and microvascular network density were also assessed by using functional slit lamp biomicroscopy. The changes of the indicators after wearing the contact lens were observed and the correlation between the subjective feelings of the wearers and the microcirculation parameters of the bulbar conjunctiva and the main factors affecting the subjective feelings of the wearers were analyzed.

Twenty-seven subjects were enrolled in the study, including 8 males and 19 females, aged (22.7±1.6) years. The OSDI score was 11.860± 7.783 before wearing the contact lens and 24.017±12.181 after wearing the contact lens. The comparison before and after wearing the contact lens was statistically significant (t=-4.356, P<0.001). The conjunctival blood flow velocity was (0.534±0.132) mm/s before wearing the contact lens and (0.587±0.134) mm/s after wearing the contact lens. The comparison was statistically significant before and after wearing the lens (t=-2.076, P=0.048). OSDI was positively correlated with blood flow velocity at 1 month after wearing the contact lens (correlation coefficient r=0.383, P=0.048). The test results of the independent variables in the generalized estimating equation model showed that time and blood flow velocity were statistically significant (P<0.05).

The blood flow velocity of the bulbar conjunctiva was increased after wearing the contact lens, and the contact lens discomfort of the wearers was positively correlated with the blood flow velocity of the bulbar conjunctiva. (Chin J Ophthalmol, 2019, 55: 98-104)

The patient was a 20-year-old female. He had undergone right eye lamellar keratoplasty and amniotic membrane covering for erosive corneal ulcer in his right eye, and then repeated attacks. This time, due to the recurrence of ulcer, the left corneal ulcer lesion debridement and partial lamellar keratoplasty were performed. Postoperatively, prednisolone acetate eye drops and tacrolimus eye drops were applied topically, and the treatment effect was satisfactory. (Chinese Journal of Ophthalmology,2019，55:141-142）

Both patients went to the doctor because of eye redness, swelling and increased secretion, and antibiotic eye drops were given without significant relief. Combined with the medical history of ocular surface chemicals splashing and the symptoms such as purulent secretion spillover from the lacrimal duct opening after squeezing the eyelid, lacrimal ductitis can be diagnosed. The prognosis was good after treatment with antibiotic eye drops through lacrimal duct orifice. (Chinese Journal of Ophthalmology,2019，55：143-144）

The patient, a 30-year-old female, experienced repeated ocular pain after chestnut ball injury to the left eye, and endothelial plaque was visible behind the cornea of the left eye, and was diagnosed as fungal keratitis. After antifungal treatment, the endothelial plaque resolved and revealed chestnut thorn-like foreign body. Deep cornea and anterior chamber chestnut thorn removal + anterior chamber irrigation were performed to remove foreign bodies. After 3 months of follow-up, slight scars were observed on the corneal endothelial surface and iris, and fungal keratitis did not recur. (Chinese Journal of Ophthalmology,2019，55：145-147）

The patient was a 6-year-old female. The parent complained that the child's left eye was red and swollen with intraocular "black mole" for 2 days, and went to the ophthalmology department of Shengli Oilfield Central Hospital. Ocular examination: binocular visual acuity was 0.8, intraocular pressure was 14 mmHg (1 mmHg =0.133 kPa) in the right eye and 16 mmHg in the left eye; The skin in the center of the lower eyelid of the left eye was slightly red and swollen, and the conjunctiva of the lower eyelid was congested. A black object with a diameter of about 2 mm was visible in the center attached to the granulation tissue (Quintessence Picture 1A in), 9 clear brown vertical stripes in the black object can be seen under a 40x slit lamp microscope (B in Quintessence Picture 1), which is not painful when pressed; The cornea is transparent, the depth of the anterior chamber is normal, the pupil is round, there is a light response, the lens is transparent, and no obvious abnormalities are seen in the fundus; No obvious abnormalities were found in the anterior and posterior segments of the right eye. Clinical diagnosis: foreign body of insect wing in conjunctiva of left eye. The black object was removed under topical anesthesia with iprocaine hydrochloride, and viscous liquid overflowed, and local anti-inflammatory and anti-infective treatment was given.

Myopia has emerged as one of the major health issues in China given its increasingly high prevalence. It is generally accepted that myopia is the result of a complex interaction of environmental exposures and genetic predisposition. Many studies have indicated that abnormal visual stimulation regulates retinal neurotransmitters and growth factors to release resulting in scleral remodeling and axial elongation through signaling pathway transduction. It has been reported that the signaling pathways play important roles in the elongation of axial length and development of myopia. In this study, we reviewed several important signaling pathways implicated myopia.(Chin J Ophthalmol, 2019, 55:148-152)

The high prevalence of myopia, the younger age of myopia, and the accelerated progress of myopia have become global common phenomena. The resulting problems such as the increase of the proportion of high myopia and the blindness caused by pathological myopia have gradually become social health dangers in today's world. Focusing on this severe social problem, Chinese scientists or myopia research based on Chinese data have carried out in-depth and achieved many results, which have become an important part of global myopia research. This article summarizes, analyzes and reviews the research related to myopia and its main results done by Chinese scientists in the past 10 years, so that more readers can understand these important research data and effectively apply them to clinical practice. (Chinese Journal of Ophthalmology,2019，55：153-160）