Differences in corneal and anterior segment morphology between diabetic vs. healthy children and adolescents: a systematic review and meta-analysis.

OBJECTIVE: To compare corneal and anterior segment morphology among children and adolescents with and without diabetes. MATERIALS AND METHODS: PubMed, Embase and Scopus databases were systematically searched. Studies that were observational in design were considered. Included studies should have been done in young children and/or adolescents and compared relevant outcomes of interest based on the diabetic status. The outcomes of interest were related to corneal morphology, morphology of lens, as well as important characteristics of anterior segment such as depth, pupillary diameter, intra-ocular pressure and axial length. The pooled effect sizes were reported as weighted mean difference (WMD). STATA software was used for statistical analysis. RESULTS: The meta-analysis included 17 studies. Diabetic children had lower corneal endothelial cell density (cells/mm2) (WMD -215.7, 95% CI: -406.5, -24.9), higher central corneal thickness (µm) (WMD 12.66, 95% CI: 5.47, 19.84), higher lenticular thickness (mm) (WMD 0.25, 95% CI: 0.13, 0.36) and density (WMD 3.02, 95% CI: 2.23, 3.81) than non-diabetic children. The anterior chamber depth (mm) (WMD -0.17, 95% CI: -0.24, -0.09) and pupillary diameter (mm) (WMD -0.61, 95% CI: -1.12, -0.10) was significantly reduced in diabetic children, compared to non-diabetic children. No differences in the corneal curvature, corneal diameter, spherical equivalent, intra-ocular pressure, axial length, tear film breakup time and Schirmer test were noted among diabetic and non-diabetic children. CONCLUSIONS: Significant structural changes in cornea and lens along with reduction in anterior chamber depth and pupillary diameter were found. These morphological changes may be indication for early and prompt management and underscore the need for more advanced ophthalmological evaluation techniques, in addition to routine examination.

[Therapeutic efficacy of ultraviolet combined with riboflavin for the rabbit bacterial keratitis].

Objective: To study the effects of ultraviolet light combined with riboflavin treatment (corneal collagen-crosslinking, CXL) on infectious control and stromal reconstruction of bacterial keratitis. Methods: Experimental Study. A Staphylococcus aureus rabbit keratitis model was established by injecting Staphylococcus aureus broth into the shallow stromal layer of the right eye cornea of New Zealand white rabbits. Forty-four rabbits that successfully established the model were randomly divided into four groups: corneal collagen cross-linking (CXL) group, antibiotic group, CXL+ antibiotic group and untreated group, with 11 rabbits in each group. Before the treatment and at 3, 7, 14 and 28 days after treatment, slit lamp corneal examination, AS-OCT and in vivo confocal microscopy (IVCM) were performed. Clinical efficacy of different treatments were evaluated at different time points. Parameters including conjunctival hyperemia, corneal ulcer, infiltration, edema, and neovascular. Histopathological examinations of corneal lesions were performed in order to detect the infiltration, inflammatory cells and repair in corneal tissue. Normal data were compared with paired t-test and non-normal data were compared with paired rank sum test before and after treatment. Kruskal-Wallis rank sum test was used to compare 4 groups of data and the generalized estimation equation is used to compare the repeated measurement data at each time point and the comparison between the groups of the treatment groups. Results: After treatment, different time points and specimens for pathological observation, we obtained the following results:Conjunctival hyperemia: in CXL and CXL+ antibiotic groups after treatment for 3 days from treatment before 3 (2, -4) and 3 (2, -3),The reduction was 2 (1, -3) and 2 (1, -2), the difference was statistically significant (Z=-3.91, -5.50; P<0.008); 14 days, the antibiotic group changed from 3 (3, -4) to 2 (1, -2) after treatment, the difference was statistically significant (Z=-5.11, P<0.008); the untreated group had no statistical significance before and after treatment. After 14 days of treatment, the area of corneal ulcer (0.08±0.11) cm(2), (0.07±0.05) cm(2) in CXL group and CXL+ antibiotic group was significantly lower than that before treatment (0.40±0.18) cm(2), (0.49±0.24) cm(2). The difference was statistically significant. Significance (Z=-3.29, -3.64; P<0.008); after 14 days of treatment, after 14 days of treatment, neovascularization in the CXL and CXL+ antibiotic groups began to resolve, 1 (1, -2) and 1 (0, -2) at 7 days of treatment. decreased to 1 (1, -1) and 0 (0, -1), the difference was statistically significant (Z=4.57, 3.80; P<0.012 5); The degree of corneal edema was significantly reduced in the CXL group and the CXL+ antibiotic group at 14 days after treatment, which was reduced from (650±154) µm and (785±255) µm before the treatment to (432±95) µm and (455±109) µm, the difference was statistically significant (t=4.50, 4.92; P=0.00); The density of corneal stromal cells was also reduced from (446±257)/mm(2), (321±145)/mm(2) to (107±66)/mm(2), (114±94)/mm(2), the difference was statistically significant (t=4.15, 4.76; P<0.05). Histopathological observation under light microscope showed that most of the corneal ulcers healed in the CXL group and the CXL+ antibiotic group at 7 days of treatment. The epithelial cells were clearly visible and misaligned, and a small amount of neutrophils in the stromal layer. The upper epithelial layer was treated for 14 days. The cells are arranged neatly, the structure is clear, and the inflammatory cells are significantly reduced. Conclusion: Ultraviolet light combined with riboflavin corneal collagen cross-linking has a certain therapeutic effect on rabbit bacterial keratitis infection control and ulcer repair, and can be used as an auxiliary treatment for antibiotics. (Chin J Ophthalmol, 2018, 54:902-910).

[A study on the diagnostic value of tear film objective scatter index in dry eye].

Objective: To study the sensitivity and specificity of tear film objective scatter index to the diagnosis dry eye disease (DED). Methods: A prospective case-controlled study. Fifty-three patients with DED and 32 healthy age- and sex-matched control subjects were included from July to October 2016. All subjects underwent the examinations sequentially as follows: evaluation of ocular surface disease symptoms using the Ocular Surface Disease Index, optical quality detection, lipid layer thickness, tear film breakup time and SchirmerⅠtest. With Optical Quality Analysis SystemⅡ, the values of modulation transfer function cut off, basic objective scatter index (OSI) and total OSI were measured. To eliminate the influence of other refractive media, the tear film OSI (TF-OSI) was calculated, and the difference in TF-OSI between two groups was analyzed with the independent-samples t test. Spearman's correlation analysis was used to detect the correlation of each parameter in the DED group. With the receiver operating characteristic curve and the area under the curve (AUC), the specificity and sensitivity of TF-OSI and other parameters were described to differentiate DED from normal eyes. Results: In the dry eye group, the value of modulation transfer function cut off (32.07±11.95) was significantly lower than the normal group (39.38±9.44, t=-3.096, P=0.003) , and the mean value and dispersion of TF-OSI (0.50±0.43, 0.52±0.81) were higher than the normal group (0.21±0.16, 0.12±0.01) (t=4.300, P=0.000, t=3.546, P=0.001) . The mean value of TF-OSI had a positive correlation with lipid layer thickness (r=0.365, P=0.007) and dispersion of TF-OSI (r=0.581, P=0.000), and a negative correlation with MTF cut off (r=-0.368, P=0.007). To the diagnostic value of DED, the mean value of TF-OSI had a sensitivity of 0.736, a specificity of 0.762, and the AUC was 0.764. The dispersion of TF-OSI had a sensitivity of 0.811 and a specificity of 0.810, and the AUC was 0.900. Conclusion: In the DED group, the mean value and dispersion of TF-OSI were higher than the normal group. With its advantages, the TF-OSI may be a new method for the auxiliary diagnosis of dry eye. (Chin J Ophthalmol, 2017, 53: 668-674).

[Epidemiologic study of tear film lipid layer thickness measurement in the population of Taishitun Community in Beijing].

Objective: To investigate the distribution of tear film lipid layer thickness (LLT) and the relationship between symptoms and signs of dry eye and tear film LLT in the population of Taishitun Community in Beijing. Methods: A cross-sectional study. From May 2016 to August 2016, three streets of Taishitun Community were randomly selected as survey districts and 540 persons were taken as investigation subjects. Every participant completed 6 items of dry eye examinations as follows: questionnaire (Ocular Surface Disease Index, OSDI), measurement of tear film LLT, tear film break-up time (TBUT), corneal and conjunctival staining, SchirmerⅠtest and the infrared meibomian photography. According to their age, all participants were divided into four groups: junior group (<18 years old), youth group (18 to 40 years old), middle-aged group (41 to 59 years old) and the elderly group (over 60 years old). With the OSDI criteria, no dry eye symptom group (score, <12 points), mild to moderate dry eye symptom group (score, 12 to 32) and severe dry eye symptom group (score, 33-100) were included. With the statistical methods of variance analysis and multivariate Logistic regression analysis, distribution of the variables of LLT and the relationship between dry eye symptoms and LLT were studied. Results: A total of 473 residents finally participated in this study, and the response ratio was 87.6%. The values of LLT were normally distributed. The average LLT was (59.87±18.50) nm [(60.16±19.15) nm in males and (59.67±18.57) nm in females], and the comparison of LLT with different genders was not statistically significant (t=0.198, P=0.843). The tear film LLT of four different age groups had statistical significance (F=15.092, P<0.05), and increased with age [(56.10±18.33) nm in the junior group, (54.60±16.29) nm in the youth group, (60.61±19.18) nm in the middle-aged group and (73.25±14.58) nm in the elderly group]. The LLT was inversely proportional to the severity of dry eye symptoms. With a thinner LLT, the symptoms of the subjects turned severe. In the elderly with different degrees of symptoms, the LLT was significantly different (F=0.019, P<0.05), while in the youth and middle-aged groups with different degrees of symptoms, the LLT was not significantly different (F=0.096, P>0.05. F=0.538, P>0.05). In the OSDI symptom questionnaire, only blurred vision and decreased visual acuity were related to the tear film LLT (P<0.05). There was no significant correlation between the TBUT, SchirmerⅠtest result, meibomian gland loss rate and the tear film LLT (P>0.05). Conclusions: In Taishitun Community of Beijing, the values of tear film LLT had a normal distribution. The LLT was positively correlated with age, but inversely correlated with the severity of the symptoms of dry eye. There was no significant correlation between the LLT and the TBUT, SchirmerⅠtest result and meibomian gland loss rate.(Chin J Ophthalmol, 2017, 53: 495-501).

[The questionnaire survey on glaucoma diagnosis and treatment in China (2016)].

Objective: To investigate the present situation of diagnosis and treatment for primary angle-closure glaucoma (PACG) and primary open-angle glaucoma (POAG) and awareness of the relevant progress among Chinese ophthalmologists. Methods: This study was a cross-sectional, non-randomized sampling survey. Participants were ophthalmologists who attended the 11st Chinese Glaucoma Society Congress during November 11 to 12, 2016. They were invited to fill out a questionnaire. The questionnaire included participants' basic information and their knowledge about glaucoma diagnosis and treatment. The data collected through questionnaire were analyzed with SAS9.4. Results: A total of 450 questionnaires were distributed and 372 valid questionnaires were retrieved, with a response rate of 82. 7%(372/450). ISGEO classification system was adopted by 58.9% (219/372) of the participants as the diagnostic criteria for PACG. Of the respondents, 48.1% (179/372) of the participants believed that "anterior chamber angle closure mechanism-based PACG classification system" was more instructive for treatment, the percentage was higher than ISGEO classification system (42.2%, 157/372). Most (72.3%, 269/372) of the participants knew the 3-minute dark room prone test, but only 27.7%(103/372) of them applied it in clinical practice. A total of 83.4%(310/372) of the participants believed that low cerebrospinal fluid pressure is a risk factor for POAG. In all, 71.8% (267/372) of the participants reported that their institutes had applied compound trabeculectomy with adjustable suture, with 76.9%(286/372) of the participants agreeing that the adjustable suture reduced the rate of complications after trabeculectomy. Conclusions: Currently, both ISGEO classification system and anterior chamber angle closure mechanism-based PACG classification system were adopted in the diagnosis and treatment of glaucoma. Low cerebrospinal fluid pressure as new risk factors for POAG has been widely acknowledged and given attentions by Chinese ophthalmologists. The 3-minute darkroom prone test and compound trabeculectomy with adjustable suture still need to be promoted. (Chin J Ophthalmol, 2017, 53: 115-120).

Common-path phase-shift interferometry surface plasmon resonance imaging system.

Surface plasmon resonance (SPR) and common-path phase-shift interferometry (PSI) techniques are integrated in a biosensing imaging system for measuring the two-dimensional spatial phase variation caused by biomolecular interactions on a sensing chip without the need for additional labeling. The common-path PSI technique has the advantage of long-term stability, even when it is subjected to external disturbances. Hence the system meets the requirements of the real-time kinetic studies involved in biomolecular interaction analysis. The proposed SPR-PSI imaging system demonstrates a detection limit of a 2 x 10(-7) refractive-index change, a long-term phase stability of 2.5 x 10(-4) pi rms for 4 h, and a spatial phase resolution of 10(-3) pi with a lateral resolution of 100 microm.