Analysis of postoperative ocular surface changes and intervention effect after pars plana vitrectomy in meibomian gland dysfunction dry eye patients.

AIM: To observe ocular surface changes after phacovitrectomy in patients with mild to moderate meibomian gland dysfunction (MGD)-type dry eye and track clinical treatment response using a Keratograph 5M and a LipiView interferometer. METHODS: Forty cases were randomized into control group A and treatment group B; the latter received meibomian gland treatment 3d before phacovitrectomy and sodium hyaluronate before and after surgery. The average non-invasive tear film break-up time (NITBUTav), first non-invasive tear film break-up time (NITBUTf), non-invasive measured tear meniscus height (NTMH), meibomian gland loss (MGL), lipid layer thickness (LLT) and partial blink rate (PBR) were measured preoperatively and 1wk, 1 and 3mo postoperatively. RESULTS: The NITBUTav values of group A at 1wk (4.38±0.47), 1mo (6.76±0.70), and 3mo (7.25±0.68) were significantly lower than those of group B (7.45±0.78, 10.46±0.97, and 11.31±0.89; P=0.002, 0.004, and 0.001, respectively). The NTMH values of group B at 1wk (0.20±0.01) and 1mo (0.22±0.01) were markedly higher than those of group A (0.15±0.01 and 0.15±0.01; P=0.008 and P<0.001, respectively); however, there was no difference at 3mo. The LLT of group B at 3mo [91.5 (76.25-100.00)] significantly exceeded that of group A [65.00 (54.50-91.25), P=0.017]. No obvious intergroup difference was found in MGL or PBR (P>0.05). CONCLUSION: Mild to moderate MGD dry eye worsens in the short term after phacovitrectomy. Preoperative cleaning, hot compresses, and meibomian gland massage as well as preoperative and postoperative sodium hyaluronate promote the rapid recovery of tear film stability.

Negative effects of enlarging internal limiting membrane peeling for idiopathic macular hole surgery.

AIM: To observe the effects of the different extents of internal limiting membrane (ILM) peeling on the surgical success and anatomical and functional outcomes of idiopathic macular hole (IMH). METHODS: In this retrospective cohort study, 36 patients were reviewed and divided into two groups according to the extent of ILM peeling: group A (18 patients), with the peeling area within one-half of the optic disc macular distance as the radius; group B (18 patients), with the peeling area larger than that of group A but did not exceed the optic disc macular distance as the radius. The main outcomes included the best corrected visual acuity (BCVA), light-adaptive electroretinography, macular hole (MH) closure rate, central macular thickness (CMT), retinal nerve fiber layer (RNFL) and ganglion cell complex (GCC) thickness [nine regions based on the Early Treatment of Diabetic Retinopathy Study (ETDRS) ring] before and 1, 3, and 6mo after surgery. RESULTS: The closure rate was 94.4% (17/18) both in groups A and B. The BCVA in both groups improved significantly compared with the preoperative values, but there was no difference between the two groups. The b-wave amplitude of the electroretinogram analysis was significantly improved in both groups compared to that of the preoperative period, with a greater increase in group A than in group B at 6mo (P=0.017). The CMT in both groups gradually decreased after surgery, and there was no difference between the two groups. The RNFL thickness of the temporal outer ring region in group B was significantly lower than that in group A at 3 and 6mo after surgery (P=0.010, 0.032). The GCC thickness of the temporal outer ring region in group B was significantly lower than that in group A at 6mo after surgery (P=0.038). CONCLUSION: Enlarging the extent of ILM peeling doesn't affect the IMH closure rate and visual acuity recovery, but the greater the extent of peeling, the greater the damage to the inner retinal structures.

Artificial intelligence can assist with diagnosing retinal vein occlusion.

AIM: To assist with retinal vein occlusion (RVO) screening, artificial intelligence (AI) methods based on deep learning (DL) have been developed to alleviate the pressure experienced by ophthalmologists and discover and treat RVO as early as possible. METHODS: A total of 8600 color fundus photographs (CFPs) were included for training, validation, and testing of disease recognition models and lesion segmentation models. Four disease recognition and four lesion segmentation models were established and compared. Finally, one disease recognition model and one lesion segmentation model were selected as superior. Additionally, 224 CFPs from 130 patients were included as an external test set to determine the abilities of the two selected models. RESULTS: Using the Inception-v3 model for disease identification, the mean sensitivity, specificity, and F1 for the three disease types and normal CFPs were 0.93, 0.99, and 0.95, respectively, and the mean area under the curve (AUC) was 0.99. Using the DeepLab-v3 model for lesion segmentation, the mean sensitivity, specificity, and F1 for four lesion types (abnormally dilated and tortuous blood vessels, cotton-wool spots, flame-shaped hemorrhages, and hard exudates) were 0.74, 0.97, and 0.83, respectively. CONCLUSION: DL models show good performance when recognizing RVO and identifying lesions using CFPs. Because of the increasing number of RVO patients and increasing demand for trained ophthalmologists, DL models will be helpful for diagnosing RVO early in life and reducing vision impairment.

Refractive outcomes after vitrectomy combined with phacoemulsification of idiopathic macular holes.

AIM: To report the refractive outcomes after vitrectomy combined with phacoemulsification and intraocular lens (IOL) implantation (phaco-vitrectomy) in idiopathic macular holes (IMH). METHODS: A total of 56 eyes with IMH (IMH group) that underwent phaco-vitrectomy and 44 eyes with age-related cataract (ARC group) that underwent cataract surgery were retrospectively reviewed. The best corrective visual acuity (BCVA), predicted refractive error (PRE), actual refractive error (ARE), axial length (AL), were measured in both groups before and 6mo after operation. The power calculation of IOL and the predicted refractive error (PRE) were calculated according to the SRK/T formula. The difference of PRE and ARE between the two groups were compared and analyzed. RESULTS: In the IMH group, the diameters of macular holes were 271.73±75.85 µm, the closure rate was 100%. The pre- and post-operative BCVA were 0.80±0.35 and 0.40±0.35 logMAR. The PRE of A-ultrasound and IOL Master in the IMH group was -0.27±0.25 and 0.10±0.66 D. The postoperative mean absolute prediction error (MAE) was observed to be 0.58±0.65 and 0.53±0.37 D in the IOL Master and A-ultrasound (P=0.758). The PRE and ARE of the IMH group were 0.10±0.66 D and -0.19±0.64 D (P=0.102). The PRE and ARE of the ARC group was -0.43±0.95 and -0.31±0.93 D (P=0.383). The difference between PRE and ARE was -0.33±0.81 and 0.09±0.64 D in the IMH and ARC groups (P=0.021). The proportion of myopic shift was 67.9% in the IMH group and 27.3% in the ARC group (P=0.004). CONCLUSION: The myopic shift can be observed in patients with IMH after phaco-vitrectomy.

Development and Application of Aptamer-Based Surface-Enhanced Raman Spectroscopy Sensors in Quantitative Analysis and Biotherapy.

Surface-enhanced Raman scattering (SERS) is one of the most special and important Raman techniques. An apparent Raman signal can be observed when the target molecules are absorbed onto the surface of the SERS substrates, especially on the "hot spots" of the substrates. Early research focused on exploring the highly active SERS substrates and their detection applications in label-free SERS technology. However, it is a great challenge to use these label-free SERS sensors for detecting hydrophobic or non-polar molecules, especially in complex systems or at low concentrations. Therefore, antibodies, aptamers, and antimicrobial peptides have been used to effectively improve the target selectivity and meet the analysis requirements. Among these selective elements, aptamers are easy to use for synthesis and modifications, and their stability, affinity and specificity are extremely good; they have been successfully used in a variety of testing areas. The combination of SERS detection technology and aptamer recognition ability not only improved the selection accuracy of target molecules, but also improved the sensitivity of the analysis. Variations of aptamer-based SERS sensors have been developed and have achieved satisfactory results in the analysis of small molecules, pathogenic microorganism, mycotoxins, tumor marker and other functional molecules, as well as in successful photothermal therapy of tumors. Herein, we present the latest advances of the aptamer-based SERS sensors, as well as the assembling sensing platforms and the strategies for signal amplification. Furthermore, the existing problems and potential trends of the aptamer-based SERS sensors are discussed.

[In vivo high-resolution imaging of rat retina with optical coherence tomography and the expression of Bcl-2, Bax, Caspase-3 mRNA during critical period plasticity].

OBJECTIVE: To observe the changes of retinal thickness during critical period plasticity in rat, and to investigate whether apoptosis participates in the structural forming of retina. METHODS: Experimental research. 50 normal newborn pups of SD rat were randomly selected in the experiment. In vivo consecutive scanning of retinal image was taken and the retinal thickness from RPE to ILM was recorded in 10 pups (20 eyes) with spectral domain optical coherence tomography (OCT) at postnatal day 14 (P14), P18, P21, P24 and P42. Bcl-2, Bax, Caspase-3 mRNA was assessed with fluorescent quantitative real-time polymerase chain reaction after total RNA extracted from 4 retinas of 2 pups at each time point from P14 to P42. Histological measurement of retinal thickness of sections with HE staining from 4 pups (8 eyes) at each time point was compared with the results of OCT scanning. TUNEL staining was used to detect the apoptotic cells in retinal cryosections of 2 pups (4 eyes) at the same time point. The data were analyzed by One-way ANOVA and Linear Regression through SPSS 11.5 software. RESULTS: There was significant difference between the retinal thickness measured through OCT in pups from P14 to P42 (F = 15.425, P = 0.001). And the values were (243.42 ± 13.83) µm at P14, (218.78 ± 8.21) µm at P18, (195.42 ± 8.02) µm at P21, (195.74 ± 14.85) µm at P24, (190.79 ± 11.70) um at P42. The retinal thickness measured through OCT decreased significantly during the first 3 weeks after birth. The results of OCT measurement had linear correlation with histology measurement (R = 0.794, P = 0.000). There was significant difference between mRNA expression of Bcl-2, Bax and Caspase-3 in pups from P14 to P42 (F = 18.684, F = 47.307, F = 49.611; P = 0.000). The relative expression of Bax and Caspase-3 peaked at P24 while Bcl-2 was much more stable. There were a lot of apoptotic cells in the ganglion cells layer, the inner nuclear layer and the outer nuclear layer during P18 to P24 by TUNEL staining. And the apoptosis alleviated at P42. CONCLUSIONS: The retinal thickness decreases when the retina continues to develop during critical period plasticity. Cirrus HD-OCT can be used as an effective instrument to show the layers of retina in rat in vivo. Apoptosis participates in the course of retinal development which possibly leads to the thinning of retina.