Epidemiological study of refractive errors in children and adolescents of Han and Li ethnics in the Ledong and Wanning areas of Hainan Province.

Background: To determine the prevalence of refractive error and ocular biometric data (corneal curvature, axial length, and central corneal thickness) in 6 to 15 years old children of Li and Han ethnicities of China. Methods: This study was a cross-sectional study. A cluster sampling method was used to select 2 nine-year consistent schools in the Ledong and Wanning areas of Hainan Province, with a total of 4,197 students, 3,969 valid data. Eyesight test, slit lamp, autorefraction after cycloplegia, and ocular biometric assessment were performed. The chi-square test and logistic regression analysis was taken as the comparative method. Results: Myopia, hyperopia, and astigmatism are defined as: myopia: SE ≤-0.50 D; hyperopia: 0.50 D

Effects of curcumin nanoparticles on proliferation and VEGF expression of human retinal pigment epithelial cells.

AIM: To investigate the effects of curcumin (Cur) nanoparticles loaded with chitosan derivatives grafted by deoxycholic acid (Chit-DC) on human retinal pigment epithelial (hRPE) cell proliferation and vascular endothelial growth factor (VEGF) mRNA expression. METHODS: Cur nanoparticles were synthesized with Chit-DC as the carrier and Cur as the supported drug. Cell counting kit-8 (CCK-8) method was used to detect the effects of different concentrations of Cur/Chit-DC, Chit-DC, and Cur on the proliferation of hRPE cells for different times. The changes of Cur/Chit-DC and Cur on hRPE cell cycle were determined by flow cytometry. Semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) was used to detect the mRNA expression levels of VEGF in hRPE cells treated with Cur, Chit-DC and Cur/Chit-DC at 10 µg/mL for 24h. RESULTS: Different concentrations of Chit-DC nanoparticle treated hRPE cells had no significant difference in terms of optical density (OD) values compared with the control group at 24h and 48h. Moreover, there was no change in the cell morphology under a light microscope. After 24h treatment with Cur/Chit-DC and Cur, the percentage of G0-G1 phase cells increased and the percentage of S phase cells decreased in all concentration groups. Cur/Chit-DC and Cur in all concentration groups inhibited the proliferation of hRPE cells in a time and dose dependent manner, and reduced the expression level of VEGF mRNA. CONCLUSION: The Cur/Chit-DC nanoparticles can release Cur continuously and have sustained release function. Both Cur/Chit-DC nanoparticles and Cur could inhibit hRPE cells cultured in vitro, and could reduce the expression level of VEGF mRNA in hRPE cells.

Comparison of corneal biological parameters between transepithelial and epithelium-off corneal cross-linking in keratoconus.

AIM: To evaluate the differences in corneal biological parameters between transepithelial and epithelium-off corneal cross-linking in keratoconus. METHODS: In our prospective clinical trial, 40 patients (60 eyes) with progressive keratoconus were randomized to undergo corneal cross-linking with transepithelial (TE group, n=30) or epithelium-off (EO group, n=30) keratoconus. Examinations comprised topography, corneal biomechanical analysis and specular microscopy at 6mo postoperatively. RESULTS: The keratometer values were not significantly different between the TE and EO corneal cross-linked groups in different periods (each P>0.05). The corneal thickness of the EO group was greater than that of the TE group at 1wk after the operation (each P<0.05). Regarding corneal biomechanical responses, the EO group showed a longer second applanation length than TE group (P=0.003). Regarding the corneal endothelial function, standard deviation of the endothelial cell size, and coefficient of variation in the cell area, the values of EO group were larger than those of TE group at 1wk (P=0.011, 0.026), and the percentage of hexagonal cells in EO group was lower than that in TE group at 1 and 6mo (P=0.018, 0.019). CONCLUSION: Epithelium-off corneal cross-linking may strengthen corneal biomechanics better than TE procedure can. However, the TE procedure with a lower ultraviolet-A irradiation intensity would be safer for corneal endothelial function.

Comparison of early changes in ocular surface markers and tear inflammatory mediators after femtosecond lenticule extraction and FS-LASIK.

AIM: To compare the short-term impacts of femtosecond lenticule extraction (FLEx) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) on ocular surface measures and tear inflammatory mediators. METHODS: This prospective comparative nonrandomized clinical study comprised 75 eyes (75 patients). Totally 20 male and 15 female patients (age 21.62±3.25y) with 35 eyes underwent FLEx, and 26 male and 14 female patients (age 20.18±3.59y) with 40 eyes underwent FS-LASIK. Central corneal sensitivity, noninvasive tear breakup time, corneal fluorescein staining, Schirmer I test, tear meniscus height, and ocular surface disease index were evaluated in all patients. Tear concentrations of nerve growth factor (NGF), interleukin-1α (IL-1α), transforming growth factor-ß1 (TGF-ß1), tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), and matrix metalloproteinase-9 (MMP-9) were assessed by multiplex antibody microarray. All measurements were performed preoperatively, and 1d, 1wk, and 1mo postoperatively. RESULTS: Patients who underwent FLEx exhibited a more moderate reduction in central corneal sensation and less corneal fluorescein staining than those in the FS-LASIK group 1wk after the procedure (P<0.01). NGF was significantly higher 1d and 1wk after surgery in the FS-LASIK group than in the FLEx group (P<0.01). By contrast, compared to those in the FLEx group, higher postoperative values and slower recovery of tear TGF-ß1, IL-1α, and TNF-α concentrations were observed in the FS-LASIK group (P<0.01). Tear concentrations of NGF, TGF-ß1, TNF-α, and IL-1α were correlated with ocular surface changes after FLEx or FS-LASIK surgery. CONCLUSION: There is less early ocular surface disruption and a reduced inflammatory response after FLEx than after FS-LASIK. NGF, TGF-ß1, TNF-α, and IL-1α may contribute to the process of ocular surface recovery.

[Differentiating the morphology of infective larvae between two human hookworms].

The morphological differentiation of the infective larvae between human Ancylostoma duodenale and Necator americanus is of great significance for the epidemiological survey of hookworm diseases and human parasitology teaching. Understanding of features of the oral spear and transverse lines on the tunica vaginalis is able to accurately differentiate the infective larvae between these two human hookworms.

Differentiating the morphology of infective larvae between two human hook-worms / 中国血吸虫病防治杂志

The morphological differentiation of the infective larvae between human Ancylostoma duodenale and Necator ameri-canus is of great significance for the epidemiological survey of hookworm diseases and human parasitology teaching.Understand-ing of features of the oral spear and transverse lines on the tunica vaginalis is able to accurately differentiate the infective larvae between these two human hookworms.

Determination of anterior segment changes with Pentacam after phacoemulsification in eyes with primary angle-closure glaucoma.

BACKGROUND: To investigate changes of anterior segment morphology in primary angle-closure glaucoma after phacoemulsification using the Pentacam system. DESIGN: Prospective, interventional study, Zhongshan Hospital of Sun Yat-sen University. PARTICIPANTS: Eighty-five eyes from 60 patients with primary angle-closure glaucoma undergoing phacoemulsification. METHODS: Intraocular pressure was measured by Goldmann applanation tonometry. Anterior segment morphology was assessed using the Pentacam camera. MAIN OUTCOME MEASURES: The intraocular pressure, central anterior chamber depth, peripheral anterior chamber depth, anterior chamber volume, pupil diameter and anterior chamber angle preoperative and 3 months postoperative. RESULTS: A total 78 eyes of 55 patients with primary angle-closure glaucoma were included in the analysis. Thirty-two eyes (41.0%) had acute primary angle-closure glaucoma, and 46 eyes (59.0%) had chronic primary angle-closure glaucoma. In both groups, statistically significant decreases in intraocular pressure and increases in anterior chamber volume, central anterior chamber depth, peripheral anterior chamber depth and anterior chamber angle inferiorly, nasally, temporally and superiorly were observed at 3 months after phacoemulsification (all P < 0.001). CONCLUSIONS: Phacoemulsification induces significant changes in anterior segment morphology in primary angle-closure glaucoma accompanied by a significant fall in intraocular pressure in the short term.

Corneal flap morphological analysis using anterior segment optical coherence tomography in laser in situ keratomileusis with femtosecond lasers versus mechanical microkeratome.

AIM: To assess and compare the flap morphology using anterior segment optical coherence tomography (AS-OCT) in laser in situ keratomileusis (LASIK) with Femto LDV femtosecond lasers versus Hansatome mechanical Microkeratome. METHODS: AS-OCT (Visante) was used to compare 1 month postoperatively the morphology of the flaps created with Femto LDV femtosecond lasers or Hansatome Microkeratome. The intended flap thickness was 110µm and 160µm respectively. The thickness of twenty-five points across each flap, which were 0mm, 1.5mm, 2.5mm, and 3.5mm to the corneal vertex on the horizontal, vertical, 45° and 135° meridian respectively, was evaluated. RESULTS: One month postoperative, the central flap thickness in the Femto LDV group was 107.43±4.70µm, while 125.90±17.50µm in the Hansatome group. The difference between the actual and the expected flap thickness was 5.61±3.84µm and 31.52±12.27µm, respectively. The Hansatome group had presented a statistically significant result (P<0.001). Flap morphology showed a more regular planar shape in the Femto LDV group and a meniscus shape in the Hansatome group. CONCLUSION: AS-OCT is a direct and fast procedure to assess the flap morphology. The morphology by AS-OCT showed that the flaps created with Femto LDV femtosecond laser were more accurate and regular than the flaps created with Hansatome microkeratome.

[Clinical investigation of iris-claw phakic intraocular lens implantation for high myopia].

OBJECTIVE: To investigate the efficacy and safety of an iris-claw phakic intraocular lens (ICPIOL) implantation for high myopia. METHODS: A consecutive group of 25 eyes in 13 patients with -7.88 to -22.88 diopters (D) of myopia was implanted with the Verisyse ICPIOL (AMO), and was examined preoperatively and 1, 7 days, 1, 3, 6, and 12 months postoperatively. Uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), manifest refraction, intraocular pressure, and complications were evaluated. RESULTS: The implantation was successful in all of 25 eyes. Compared with preoperative data, UCVA, BCVA, and spherical equivalent (SE) were improved significantly. At 12-month postoperatively, UCVA was 0.5 or better in all eyes, in which the UCVA in 71.43% eyes was 0.8 or higher; No loss of BCVA was found, 2 lines of BCVA improvement was obtained in 95.24% of patients with ICPIOL, and 1 line BCVA improvement was seen in 4.76% of patients; the power of refraction in all eyes implanted with ICPIOL was stabilized within the variation of +/- 0.50D (71.43%), and +/- 1.00D (85.71%). The corneal endothelial loss was insignificant. No severe complications occurred. CONCLUSIONS: At short-term follow-up, the implantation of the ICPIOL proved to be safe and effective for the correction of myopia in phakic eyes. However, longer follow-up with larger numbers of patients is necessary to evaluate long-term complications.

[Effects of experimentally induced hyperopic optical defocus on refractive status of adolescent monkeys].

OBJECTIVE: To determine if chronic optical defocus alters refractive development in monkeys at ages corresponding to the typically developed age of myopia in human children. METHODS: A hyperopic anisometropia was produced in 7 adolescent rhesus monkeys by photorefractive keratectomy (PRK). The laser procedures were performed when the monkeys were 2.0 to 2.5 years old, which corresponded to approximately 8-10 years old in human being. The ocular effects of the induced anisometropia were assessed periodically by corneal topography, retinoscopy and A-scan ultrasonography. RESULTS: By about 30 days post-PRK, the experimentally induced refractive errors was stabilized and the treated eyes were between +0.75 and +2.25 D more hyperopic than their fellow eyes. Subsequently, 7 monkeys showed systematic reductions in the degree of anisometropia. Although some regression in corneal power occurred, the compensating refractive changes were primarily due to the differences in vitreous chamber growth (r = 0.74, P = 0.046). CONCLUSIONS: Vision-dependent mechanisms that are sensitive to refractive error are still active in adolescent primates and probably play a role in maintaining stable refractive errors in the two eyes. Consequently, conditions that result in consistent hyperopic defocus could potentially contribute to the development of juvenile onset myopia in children.

[Comparison of retinal morphology and ultrastructure in defocus-induced myopia and form-deprivation myopia in rhesus monkeys].

OBJECTIVE: To investigate the changes of retinal ultrastructure of defocus-induced myopia and form-deprivation myopia in infant rhesus monkeys. METHODS: A -3.00 D spectacle lens (n = 9) or diffuser lens (n = 6) was worn over one eye and a zero-powered lens over the fellow eye in 15 healthy rhesus monkeys ranging in age from 1 to 1.5 months. The eyes were examined periodically with corneal topography, cycloplegic retinoscopy, A-scan ultrasonography, and optical coherence tomography (OCT). Three months later, light and electron microscope were used to observe the changes of the retina. RESULTS: In 15 monkeys, all eyes treated with -3.00 D spectacle lens or diffuser lens developed defocus-induced myopia or form-deprivation myopia. Not only defocus-induced myopia, but also form-deprivation myopia showed elongation of rod outer segment, decreased membrane disc of cone outer segment, increased clearance of the membrane disc and decreased thickness of the neurosensory retina (RNL) as compared with the control eyes (P < 0.05). There were no significant differences between the mean OCT and histomorphometric thickness of RNL and retinal pigment epithelium (RPE) after the correction of dehydration (P > 0.05). CONCLUSIONS: There are significant differences in retinal ultrastructure between experimental myopic eyes and control eyes. But the morphological changes in the retina of the defocus-induced myopia showed no significant difference as compared with form-deprivation myopia. The role of changes of retinal ultrastructure in the development of myopia needs further studies. OCT can be used to examine the changes of RNL and RPE in experimental myopia in vivo.

[The study of photorefractive keratectomy induced defocus on emmetropization in infant monkeys].

OBJECTIVE: To investigate the effect of photorefractive keratectomy (PRK) induced defocus on emmetropization in infant rhesus monkeys and to determine the role of visual feedback on emmetropization. METHODS: PRK was performed in 8 healthy rhesus monkeys age ranging from 2 to 3 months. Either 3.00 D of relative hyperopic or myopic defocus was produced in one eye and the fellow eye as controls. The eyes were examined periodically with corneal topography, cycloplegic retinoscopy, A-scan ultrasonography, and slit-lamp biomicroscopy. RESULTS: All operated eyes demonstrated re-epithelialization within 3 days post-surgically and maintained transparent. Compensating axial length growth occurred throughout the observation period. The rate of vitreous chamber elongation varied with the post-PRK refractive status of the eye. The hyperopia-induced eyes exhibited a vitreous chamber elongation faster than the fellow eyes (t = 3.656, P = 0.0354), whereas myopia-induced eyes demonstrated a vitreous chamber elongation slower than the fellow eyes (t = 3.576, P = 0.0374). CONCLUSIONS: PRK-induced-defocus altered axial growth rates and emmetropization in infant monkeys predictably. These results indicate that primate emmetropization is regulated by visual feedback and correction of refractive error on children should be careful. PRK-induced-defocus is a promising method for myopic animal model and for the investigation of vision science.

Expression of pax-6 in rhesus monkey of optical defocus induced myopia and form deprivation myopia.

BACKGROUND: Pax-6 gene plays an important role in the process of eye development. This study was to determine the role of pax-6 in the axial myopia produced by hyperopic optical defocus and form deprivation in infant monkeys. METHODS: Among seven normal infant rhesus monkeys (aged 1 to 1.5 months), five wore -3.00 D spectacle lenses over their right eyes and zero-powered lenses over their left eyes. Monocular form deprivation was produced by eyelid fusion in two monkeys. Ten weeks later, the monkeys were sacrificed by an overdose of barbiturates and their eyes were removed immediately. A 5 mm x 5 mm button of retina and sclera was taken from the posterior poles along with a 4-mm optic nerve. RNA was isolated separately from each of these three types of tissues. After that, reverse transcription polymerase chain reaction (RT-PCR) was used for determining gene expression in the retina, sclera and optic nerve. Semi-quantitative analyses were performed on the PCR products. RESULTS: As expected, the optically induced hyperopic defocus and the form deprivation produced myopic growth. For the lens-treatment monkeys, pax-6 gene expression in the retinas of the defocused eyes was significantly higher than in the retinas of the left eyes (t = 5.703, P = 0.005). However, there were no analogous significant differences between pax-6 expression in the scleras or the optic nerves. For the two form-deprived monkeys, there were no obvious differences in pax-6 gene expression in the retinas or the optic nerves. CONCLUSION: The result that the expression of pax-6 was enhanced by hyperopic defocus in the infant monkey retina suggests that pax-6 may be involved in vision-dependent eye growth and emmetropization.