Anji Wei

A new tonometer--the Corvis ST tonometer: clinical comparison with noncontact and Goldmann applanation tonometers.

PURPOSE To compare intraocular pressure (IOP) measurements obtained using the Topocon noncontact tonometer (NCT), the Goldmann applanation tonometer (GAT), and the Corvis ST (CST), a newly developed tonometer with features of visualization and measurement of the corneal deformation response to an air impulse. A secondary objective was to assess the agreement among the devices. METHODS Fifty-nine participants, including glaucoma patients (36 cases) and control volunteers (23 cases), were enrolled. One eye was selected randomly for further study. IOP measurements were obtained with the CST, NCT, and GAT by two experienced clinicians. IOP values were compared. Intraobserver variability and interobserver variability were assessed by the coefficient of variation and intraclass correlation coefficient. Device agreement was calculated by Bland-Altman analysis. RESULTS Mean IOP for all examined eyes was 18.9 ± 5.8 mm Hg for CST, 21.3 ± 6.8 mm Hg for NCT, and 20.3 ± 5.7 mm Hg for GAT. There was no statistically significant difference in IOP measurements among the tonometers except between the CST and NCT. Correlation analysis showed a high correlation between each pair of devices (all P < 0.001). The CST displayed the best intraobserver variability and interobserver variability. Bland-Altman analysis revealed a bias between CST and GAT, CST and NCT, and GAT and NCT of -1.3, -2.4, and -1.1 mm Hg, with 95% limits of agreement of -6.2 to 3.5 mm Hg, -10.1 to 5.2 mm Hg, and -8.3 to 6.2 mm Hg, respectively. CONCLUSIONS The CST offers an alternative method for measuring IOP. IOP measurements taken with these devices may not be interchangeable.

Assessment of tear film stability in dry eye with a newly developed keratograph.

Purpose: To investigate the applicability of a newly developed corneal topographer in assessing tear film stability. Methods: This is a prospective, case–control study. Forty-four Chinese dry eye patients and 41 normal subjects were recruited. Noninvasive tear film break-up time (NI-BUT) was measured using a new method based on a corneal topographer equipped with modified scan software. The reliability of the measurements was determined. Then, the correlations between the NI-BUT and the traditional fluorescein tear film break-up time, Schirmer I test values, and inferior tear meniscus height measurements were determined. The receiver operating characteristic curve technique was used to evaluate the NI-BUT examination in the diagnosis of dry eye. Results: In total, a significant difference between the NI-BUT and the fluorescein tear film break-up time was found (3.2 ± 2.3 seconds vs. 5.2 ± 3.4 seconds; P < 0.001). The coefficient of variation and intraclass correlation coefficient values of NI-BUT were 12.8% and 0.93, respectively, for NI-BUT for intraobserver repeatability and 15.4% and 0.88, respectively for interobserver repeatability. The NI-BUT showed a good correlation with other dry eye examinations (all P < 0.05). In addition, the NI-BUT was significantly shorter in dry eye patients (2.0 ± 0.2 seconds) than in normal subjects (4.3 ± 0.3 seconds; P < 0.001). When the cutoff value was set at <2.65 seconds, the sensitivity and specificity of the test were 84.1% and 75.6%, respectively. Conclusions: Measurements of NI-BUT obtained with the newly developed corneal topographer may provide a simple, noninvasive screening test for dry eyes with acceptable sensitivity, specificity, and repeatability.

Evaluation of age-related changes in human palpebral conjunctiva and meibomian glands by in vivo confocal microscopy.

Purpose: To investigate the age-related changes in human palpebral conjunctiva and meibomian glands by in vivo confocal microscopy. Methods: Forty-nine healthy volunteers (20 men and 29 women; mean age, 43.4 ± 22.7 years; range, 9-85 years) were recruited from the community. Laser scanning confocal microscopy was used to observe and measure the upper palpebral conjunctiva and meibomian glands. Customized software was used to analyze the images. The quantitative parameters included the mean densities of goblet cells, conjunctival basal epithelium, Langerhans cells, and meibomian glandular acinar units. Results: Mean densities of goblet cells, conjunctival basal epithelium, Langerhans cells, and meibomian glandular acinar units were 1050 ± 495 cells per square millimeter, 2979 ± 510 cells per square millimeter, 32 ± 16 cells per square millimeter, and 71 ± 27 glands per square millimeter in total subjects, respectively. No statistically significant difference in these 4 parameters was observed between the male and female subjects. Significant negative correlations were noted between age and goblet cell density (r = −0.646; P < 0.0001) and meibomian glandular acinar unit density (r = −0.585; P < 0.0001). However, no significant correlation was detected between the densities of conjunctival basal epithelium or Langerhans cell density and age. Conclusions: Age-related changes under laser scanning confocal microscopy included decreased densities of goblet cells in human palpebral conjunctiva and the acinar units in meibomian glands.

Spectral-Domain Optical Coherence Tomographic Assessment of Schlemm's Canal in Chinese Subjects with Primary Open-angle Glaucoma

PURPOSE To evaluate in vivo features of Schlemms canal (SC) in patients with primary open-angle glaucoma (POAG) with spectral-domain optical coherence tomography (SD-OCT) and to investigate the relationship of SC size with intraocular pressure (IOP) and glaucoma severity. DESIGN Prospective, comparative study. PARTICIPANTS Fifty Chinese patients with newly diagnosed POAG who had not undergone surgery and 50 normal Chinese subjects from a population-based, cross-sectional study in Shanghai. METHODS All participants underwent SD-OCT. The diameter and area of SC were examined in the temporal and nasal sections and measured with customized software. MAIN OUTCOME MEASURES Patient demographics, repeatability and reproducibility assessed with the coefficient of variation (CV) and the intraclass correlation coefficient (ICC), SC parameters and their correlation with IOP, and the mean deviation (MD) of the visual field were analyzed. RESULTS The percentage of sections in which SC was observable was similar between eyes with POAG and normal eyes, and ranged from 78% to 86%. For intraobserver repeatability, the CV and ICC values were 7.9% and 0.97 for diameter, and 13.8% and 0.83 for area, respectively. For interobserver repeatability, the CV and ICC values were 13.6% and 0.89 for diameter, and 13.4% and 0.80 for area, respectively. Significant differences between the 2 groups were found for the average SC area (11332 ± 2015 μm(2) vs. 13991 ± 1357 μm(2); P<0.001), but not for the SC diameter (40.2 ± 7.1 μm vs. 45.2 ± 4.0 μm; P = 0.195). In addition, the mean IOP values correlated well only with the SC area (ρ = -0.674, P<0.001), not with the SC diameter (ρ = -0.103, P = 248). No significant correlations were found between the MD values and the SC parameters. CONCLUSIONS Eyes with POAG have a decreased SC area compared with normal eyes. A correlation between the SC area and the IOP also was observed. However, the degree of glaucoma damage was not consistently associated with the SC area. Spectral-domain OCT could be used for investigating SC changes in patients with glaucoma.

T-style keratoprosthesis based on surface-modified poly (2-hydroxyethyl methacrylate) hydrogel for cornea repairs

Corneal disease is a common cause of blindness, and keratoplasty is considered as an effective treatment method. However, there is a severe shortage of donor corneas worldwide. This paper presents a novel T-style design of a keratoprosthesis and its preparation methods, in which a mechanically and structurally effective artificial cornea is made based on a poly(2-hydroxyethyl methacrylate) hydrogel. The porous skirt was modified with hyaluronic acid and cationized gelatin, and the bottom of the optical column was coated with poly(ethylene glycol). The physical properties of the T-style Kpro were analyzed using ultraviolet and visible spectrophotometry and electron scanning microscopy. The surface chemical properties were characterized using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The surface modification in the spongy skirt promoted cell adhesion and produced a firm bond between the corneal tissue and the implant device, while the surface modification in the optic column resisted cell adhesion and prevented retroprosthetic membrane formation. Through improved surgical techniques, the novel T-style keratoprosthesis provides enough mechanical stability to facilitate long-term biointegration with the host environment. In vivo implantation experiments showed that the T-style keratoprosthesis is a promising cornea alternative for patients with severe limbal stem cell deficiency and corneal opacity.

Schlemm's Canal Expands After Trabeculectomy in Patients With Primary Angle–Closure Glaucoma

PURPOSE To evaluate the in vivo changes in the Schlemms canal (SC) in patients with primary angle-closure glaucoma (PACG) after trabeculectomy using spectral-domain optical coherence tomography (SD-OCT). METHODS Forty eyes of 40 patients with PACG who underwent trabeculectomy were included. All participants underwent SD-OCT. The diameter and area of SC were examined and measured before and within 1 month after trabeculectomy. All SD-OCT images were processed using adaptive compensation algorithm to improve contrast and image quality. Multivariate linear regression analysis was performed for predictors of percentage change in the mean SC diameter and area. RESULTS The mean age of participants was 60.5 ± 14.6 years. Adaptive compensation significantly increased the percentage of sections in which SC was observable in the subjects studied from 52.5% (21/40) to 75.0% (30/40), which has acceptable intraobserver and interobserver repeatability. There was a significant increase in the SC diameter and area at the follow-up examination compared with the baseline value (SC diameter: 34.2 ± 6.2 μm vs. 28.4 ± 6.1 μm; SC area: 8117 ± 1942 μm(2) vs. 5200 ± 996 μm(2); all P < 0.001). After multivariate analysis, the only variable related to changes in SC was percentage change in IOP (SC diameter, P = 0.002; SC area, P < 0.001). In addition, the magnitude of the change in the SC area also correlated with angle opening distance at 750 μm from the scleral spur at baseline. CONCLUSIONS Expansion of SC was observed after trabeculectomy in PACG patients. The degree of SC expansion was related to the extent of the IOP decrease.

Evaluation of Age-Related Changes in Noninvasive Tear Breakup Time

Purpose To establish normal noninvasive tear film breakup time (NI-BUT) values in the Chinese population and investigate age-related changes in NI-BUT using a newly developed Keratograph. Methods Forty normal volunteers with a mean age of 32.8 ± 16.7 years were recruited for this study. Clinical and demographic data, including age, gender, fluorescein tear film breakup time (FBUT), and Schirmer I test values were collected from the subjects. Noninvasive tear film breakup time was measured using a new method based on a corneal topographer equipped with a modified scan software. The correlations between the NI-BUT, age, and gender were determined. Results In total, a significant difference between the NI-BUT and the FBUT was found (4.9 ± 2.4 seconds vs. 9.0 ± 3.0 seconds; p < 0.001). No statistically significant difference in the NI-BUT was observed between the male and female subjects (5.5 ± 2.0 seconds vs. 4.5 ± 2.5 seconds; p = 0.137). In addition, no significant correlation was detected between the NI-BUT and age (0.143, p = 0.321). Conclusions The NI-BUT values found in this study are much lower than those of previous reports. Our results show no significant differences in tear film stability with age. The tear physiology of the Chinese population may not be the same as in Western populations.

In vivo confocal microscopy of meibomian glands and palpebral conjunctiva in vernal keratoconjunctivitis

Purpose: To investigate the correlations between conjunctival inflammatory status and meibomian gland (MG) morphology in vernal keratoconjunctivitis (VKC) patients by using in vivo confocal microscopy (CM). Materials and Methods: Nineteen VKC patients (7 limbal, 7 tarsal, and 5 mixed forms) and 16 normal volunteers (controls) were enrolled. All subjects underwent CM scanning to obtain the images of upper palpebral conjunctiva and MGs. Inflammatory cell (IC) density in palpebral conjunctival epithelial and stromal layers, Langerhans cell (LC) density at lid margins and the stroma adjacent to the MG, and MG acinar unit density (MGAUD) were recorded. The longest and shortest diameters of MG acinar were measured. The Kruskal-Wallis test was used to compare the parameter differences whereas the Spearmans rank correlation analysis was applied to determine their correlations. Results: Among all groups, no significant statistical differences were found in epithelial and stromal IC densities, mean values of MG acinar unit densities, or longest and shortest diameters. Both LC parameters in the tarsal-mixed groups were significantly higher than those in the limbal and control groups. All LC densities of VKC patients showed a positive correlation with MGAUD and shortest diameter. Conclusions: In VKC patients, the conjunctival inflammatory status could be associated with the MG status. In vivo CM is a noninvasive, efficient tool in the assessment of MG status and ocular surface.

Vision-Related Quality of Life in Patients with Infectious Keratitis

Purpose To determine the vision-related quality of life (VR-QOL) in patients with infectious keratitis using the 25-item National Eye Institute Visual Function Questionnaire (NEI VFQ-25). Methods Sixty-five patients with infectious keratitis (IK) were enrolled in the study. The NEI VFQ-25 scores and clinical and demographic data, including age, gender, pathogen, best corrected visual acuity (BCVA), and duration of the disease, were collected from the subjects. The subscale and composite scores were calculated and analyzed. Correlations between the VFQ-25 scores and the clinical and demographic features were also explored. Results The mean age of enrolled subjects was 48.4 years (SD, 16.2), with 44 males (67.7%). The microbial pathogens were viruses (n = 48, 73.8%), fungi (n = 13, 20.0%), and bacteria (n = 4, 6.2%). The mean scores of each VFQ-25 subscale ranged from 31.9 (SD, 28.6) for role difficulties to 92.7 (SD, 13.1) for color vision; the mean composite score was 58.1 (SD, 19.2). Significant differences in scores were observed only in the subscale of dependency among educational levels and in the mental health subscale and the composite among the three pathogen groups. Multivariate regression analysis revealed that VFQ-25 composite score correlated significantly with the BCVA of the worse-seeing eye, duration of the disease, history of operation (for IK treatment), and gender. Conclusions Infectious keratitis has extensive impacts on patients and VR-QOL. The BCVA of worse-seeing eye, duration, history of operation for IK treatment, and gender contributed independently to VR-QOL. Early treatment should be encouraged to obtain better visual prognosis and VR-QOL for patients with IK.

Vitamin A Palmitate and Carbomer Gel Protects the Conjunctiva of Patients With Long-term Prostaglandin Analogs Application.

Purpose:To investigate the protective effects of vitamin A palmitate and carbomer gel on the morphology of conjunctival epithelium and density of goblet cells (GCs) in patients on long-term prostaglandin analogs (PGAs) application. Methods:In this prospective cohort study, 23 primary open-angle glaucoma patients and 7 normal-tension glaucoma patients prescribed PGAs for >1 year were enrolled into 3 identical clinical trials and randomized into 3 groups (10 per group). Patients were treated twice daily with vitamin A palmitate eye gel 0.1%, or carbomer eye gel 0.2%, or no additional application of these 2 drugs. Ocular surface disease index questionnaires, Schirmer 1 test without anesthesia, tear break-up time test, and GCs density assessment by in vivo confocal microscopy and conjunctival impression cytology analysis were performed at baseline and at months 1, 3, and 6 of the study. Results:Both vitamin A palmitate and carbomer gel led to a significant improvement in ocular surface disease index questionnaires score and prevented the gradual decline in tear break-up time. Vitamin A palmitate significantly increased the GC density after treatment. The GC density assessed by in vivo confocal microscopy positively correlated with that measured by conjunctival impression cytology. Conclusions:Vitamin A palmitate and carbomer eye gel can effectively relieve dry eye symptom caused by long-term application of PGAs by increasing the GCs density and thereby reducing the toxicity to the conjunctiva. Vitamin A palmitate and carbomer eye gel may be valuable alternatives for glaucoma patients who prescribed long-term PGAs.