Silicone oil as a corneal lubricant to reduce corneal edema and improve visualization during vitrectomy.

AIM: To evaluate the efficacy and safety of silicone oil (SO) as a corneal lubricant to improve visualization during vitrectomy. METHODS: Patients who underwent vitreoretinal surgery were divided into two groups. Group 1 was operated on with initial SO (Oxane 5700) as a corneal lubricant. Group 2 was operated on with initial lactated ringer's solution (LRS) and then replaced with SO as required. Fundus clarity was scored during the surgery. Fluorescein staining was performed to determine the damage to corneal epithelium. RESULTS: Totally 114 eyes of 114 patients were included. Single SO use maintained a clear cornea and provided excellent visualization of surgical image. In group 1, the fundus clarity was grade 3 in 41/45 eyes and grade 2 in 4/45 eyes. In group 2, corneal edema frequently occurred after initial LRS use. The fundus clarity was grade 3 in 19/69 eyes, 2 in 37/69 eyes and 1 in 13/69 eyes (P<0.05). SO was applied in 29 eyes of initial LRS use with subsequent corneal edema, which eliminated the corneal edema in 26 eyes. Corneal fluorescein staining score in group 1 was 0 in 28 eyes, 1 in 11 eyes and 2 in 6 eyes, and 40, 20 and 9, respectively, in group 2 (all P>0.05). CONCLUSION: The use of SO as a corneal lubricant is effective and safe for preserving and improving corneal clarity and providing clear surgical field during vitrectomy.

Artificial intelligence improves accuracy, efficiency, and reliability of a handheld infrared eccentric autorefractor for adult refractometry.

AIM: To evaluate the accuracy, efficiency, and reliability of a handheld infrared eccentric autorefractor (hICA) with artificial intelligence (AI) by comparing its refraction measurements to those recorded using hICA and a clinical table-mounted automatic refractor (TAR). METHODS: A cross-sectional study using three optometers, including hICA with or without AI and TAR, for refractometry of adults (aged 19-49 years old) with no signs of ocular disease or trauma in the absence of cycloplegia. Right and left eye refraction data were recorded, including the spherical equivalent (SE), diopter of spherical power (DS), diopter of cylindrical power (DC) decomposed into vectors J0 and J45, and measurement times. To avoid analytical difficulties associated with the interdependence of observations between eyes from the same individual, the Generalized Estimation Equation was used to compare the SE, DS, J0 and J45 measurements, and the times thereof, among the different groups. The intraclass correlation coefficient (ICC) and Spearman's rank correlation coefficient were used to evaluate correlations among the measurements recorded by the three different instruments. Bland-Altman were used to analyze the precision of the equipment by the agreement. RESULTS: A total of 70 patients (140 eyes; mean age: 31.37y; range: 19-49y) were assessed using refractometry. In a brightly lit environment, there was no significant difference between the mean SE recorded using TAR and that recorded using hICA with AI or without AI (both P>0.05). In an intense-light environment, hICA equipped with AI showed a better detection rate than without AI. Light intensity had a greater effect on dioptric measurements recorded using hICA without AI (P<0.001) than on those recorded using the one equipped with AI (P<0.05). Measurement times varied significantly between the different light intensities and instruments (P<0.05). CONCLUSION: For the normal human eyes, AI may improve the accuracy, efficiency, and reliability of measurements recorded using hICA in various light environments.

Scleral remodeling in myopia development.

With the increasing prevalence in recent years, myopia has become an essential global health concern. In most instances, an increased axial length of the eye is the structural cause of nearsightedness. The scleral remodeling, primarily dependent on the scleral extracellular matrix (ECM) changes, is significantly linked to eye lengthening. Scleral remodeling plays a critical function in the incidence and progression of myopia. This mini-review will focus on recent research progress of scleral remodeling in the hope of providing new ideas for the prophylaxis and treatment of myopia.

Association between MMP/TIMP Levels in the Aqueous Humor and Plasma with Axial Lengths in Myopia Patients.

PURPOSE: The present study investigated the profiles of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) of the aqueous humor (AH) and plasma (PL) in myopia patients, to determine whether there was an association between these levels with their axial length (AL) and to investigate if MMPs/TIMPs were regulated locally or systemically. METHODS: A cross-sectional study was conducted. Thirty-nine patients (78 eyes) diagnosed with high myopia were recruited. The AL was measured using IOL Master. And the patients were divided into three groups based on their AL, Group A (AL ≤ 26 mm), Group B (26 < AL ≤ 28 mm), and Group C (AL > 28 mm). The AH in both eyes and blood samples were collected before the patients underwent implantable collamer lens surgery. In all, 78 samples of the AH and 39 samples of the PL were analyzed using MILLIPLEX map assays, followed by statistical analyses of the results. RESULTS: There were 8 patients (16 eyes) in Group A, 22 patients (44 eyes) in Group B, and 9 patients (18 eyes) in Group C. MMP-1 (p = 0.014, Β = 0.118), MMP-2 (p ≤ 0.001, Β = 0.278), MMP-9 (p ≤ 0.001, Β = 0.019), and TIMP-1 (p = 0.014, Β = 0.062) in the AH were positively associated with the AL. MMP-1 (p = 0.004, Β = 0.001) and TIMP-1 (p = 0.030, Β = 1.171) concentrations in the PL increased linearly with longer ALs. No concentration-dependent relationship was found between MMP-2 in the PL and AL. CONCLUSIONS: There was a consistent relationship between MMP-2 in the AH and AL. AL was not consistently or substantially affected by MMP-2 in the PL, indicating myopia formation was possibly a localized process. Associations among MMP-1, MMP-9, and TIMP-1 in the AH and AL were also observed.

Human aqueous humor levels of transforming growth factor-ß2: Association with matrix metalloproteinases/tissue inhibitors of matrix metalloproteinases.

The present study aims to investigate the association of transforming growth factor-ß2 (TGF-ß2) and matrix metalloproteinases (MMPs), MMP-2 and MMP-3, and tissue inhibitors of matrix metalloproteinases (TIMPs), TIMP-1, TIMP-2 and TIMP-3 in the aqueous humor of patients with high myopia or cataracts. The levels of TGF-ß2 and MMPs/TIMPs were measured with the Luminex xMAP Technology using commercially available Milliplex xMAP kits. The association between TGF-ß2 and MMPs/TIMPs levels was analyzed using the Spearmans correlation test. The levels of TGF-ß2 were identified to be positively correlated with the levels of TIMP-1 and TIMP-3 (TIMP-1: r=0.334; P=0.007; TIMP-3: r=0.309; P=0.012). The levels of MMP-2, MMP-3 and TIMP-2 did not significantly correlate with TGF-ß2 levels (P>0.05). A positive correlation was identified between TGF-ß2 and TIMPs in the aqueous humor of human eyes with elongated axial length. It appears that TGF-ß2 stimulates the expression of TIMPs as a compensatory reaction to the development of high myopia.

Improvement in visual function and quality of life following a blindness prevention surgery program in a rural area of Eastern China.

The aim of this study was to assess the changes in visual function (VF) and quality of life (QOL) among patients following blindness prevention surgery in a rural area of Eastern China. The prospective study selected cataract patients via mobile eye screening camps. VF and QOL questionnaires originally developed by Fletcher et al were completed prior to and 6 months after surgery. Small-incision cataract surgery (SICS) with posterior chamber intraocular lens (IOL) implantation was performed on patients by a blindness prevention surgery group. The VF and QOL scores of 178 cataract patients preoperatively were 48.58±31.18 and 65.97±26.77, respectively. The scores decreased in proportion to decreasing vision status. The VF and QOL scale scores were significantly correlated with the vision grade of the patient (rVF=-17.2093, t=-10.87, P<0.001, rQOL=-13.1399, t=-8.87, P<0.001) and age (rVF=-0.6505, t=-3.87, P<0.001, rQOL=- 0.3309, t=-2.10, P=0.037). A total of 131 patients responded to the second survey, VF and QOL scores increased significantly over a six-month postoperative period (VF=83.21±16.40, P<0.001; QOL=86.53±16.33, P<0.001). The VF scale scores were correlated with the grade of vision and residence area, the QOL scale scores were correlated with the grade of vision and gender. The VF and QOL of patients were significantly improved by performing SICS with posterior chamber IOL implantation collectively in a short period in rural areas of Eastern China. It is important to follow-up cataract patients postoperatively as untreated complications of the surgery may affect the stability of VF and QOL postoperatively.

Microdissection of guinea pig extraocular muscles.

The guinea pig, a widely used experimental animal, has been used in myopia research in recent years. The structure of the extraocular muscles is important in research on eyeball movement, regulation of movement, binocular vision and surgical intervention. In this study, the anatomy and the structure of the extraocular muscles of guinea pigs were investigated. Five guinea pig eyes were dissected under a surgical microscope immediately after sacrifice, and an additional five were fixed in 10% formaldehyde solution and dissected under a surgical microscope 1 week after sacrifice. The guinea pig eye has seven extraocular muscles: two medial rectus muscles, one superior rectus muscle, one inferior rectus muscle, one superior oblique muscle and one inferior oblique muscle. The retractor bulbi muscle fibers surround the optic nerve longitudinally and insert circumferentially into the posterior pole of the eyeball. The lateral rectus was not found. Our results showed that there is a disparity between the structure of guinea pig extraocular muscles and that of humans.

[A cross-sectional survey of blindness and low vision among adults aged 60 years and above in Xinchengqiao Blocks, Nantong].

OBJECTIVE: To investigate the prevalence and causes of blindness and low vision among adults aged > or = 60 years in the urban population of Nantong. METHODS: Cluster sampling was used to select 8 from 14 communities in Xinchengqiao Blocks, in which all individuals aged > or = 60 years were visited. The visual acuity without correction and the presenting acuity with the participants' habitual distance correction were measured separately for each eye. In individuals with visual acuity less than 0.6, pinhole visual acuity was tested with pinhole spectacle. External eye, anterior segment and ocular fundus were examined by the ophthalmologist using a slit lamp-microscope and direct ophthalmoscopy. The survey was preceded by a pilot study. RESULTS: Of 3352 enumerated subjects, 3040 individuals participated in this survey (90.69% response rate). According to pinhole visual acuity and World Health Organization (WHO) visual impairment criterion (blindness: less than 0.05 in the better eye; low vision: less than 0.3 to 0.05 in the better eye), the prevalence of blindness and low vision was 1.35% and 1.84% respectively. The prevalence of blindness and low vision for females were 1.92% and 2.33%, respectively, which were differenced from that in males (0.66% and 1.24%, respectively). The prevalence of blindness and low vision increased with age. The survey showed that the most important cause leading to blindness and low vision was cataract. According to the presenting visual acuity and visual impairment criterion (blindness: less than 0.1 in both eyes), the prevalence of blindness and visual impairment was 1.58% and 13.59%, respectively, 2.10% and 15.98% in females and 0.95% and 10.66% in males, respectively. The prevalence of blindness and visual impairment was raised with increasing age. Cataract was also the leading cause for blindness. CONCLUSIONS: The prevalence of blindness in the Nantong area was lower than that in northern, southern and western China. Females and illiteracy were more likely to have blindness and low vision than that of males and literate. The leading causes of blindness in Nantong are, in descending sequence, cataract, ocular fundus diseases, ametropia and corneal scar/opacity.