Yujing Yang

Age-Related Changes in Human Corneal Epithelial Thickness Measured With Anterior Segment Optical Coherence Tomography

PURPOSE To measure corneal and limbal epithelial thickness (ET) in normal subjects and to evaluate its variation with age by using anterior segment optical coherence tomography (AS-OCT). METHODS A total of 180 normal subjects (180 healthy eyes) were enrolled and divided into four groups according to age: A (0-20 years), B (21-40 years), C (41-60 years), and D (>60 years). Cornea and limbus were imaged with OCT. Corneal ET (CET) was obtained automatically by the built-in analysis software of the OCT system. Limbal ET (LET) in four quadrants was manually measured from OCT images. RESULTS Corneal ET of a central 2-mm diameter zone in groups A, B, C, and D were 53.4 ± 2.8 μm, 53.4 ± 2.7 μm, 53.2 ± 3.0 μm, and 52.9 ± 3.3 μm, respectively, N showing no significant change with aging. In the paracentral zone extending to 6-mm diameter, correlation analysis suggested that CET was inversely associated with age (P < 0.05). Limbal ET in the nasal and the temporal quadrants were similar and decreased with aging, the averages were 58.3 ± 8.1 μm, 54.1 ± 6.1 μm, 51.2 ± 6.1 μm, 51.6 ± 5.2 μm for groups A, B, C and D, respectively; while age seemed to have no effect on LET of the superior and the inferior quadrant. CONCLUSIONS The paracentral corneal epithelium, as well as the nasal and temporal limbal epithelium, became thinner with aging, while the central CET seemed to remain constant. Measurement with AS-OCT of the corneal and limbal ET could aid in clinical assessment and planning treatments of the cornea.

Corneal Epithelial Thickness Map in Long-Term Soft Contact Lenses Wearers

Purpose To map the corneal epithelial thickness in vivo with Fourier-domain optical coherence tomography in long-term soft contact lens (SCL) wearers. Methods This is a cross-sectional observational study. Forty eyes from 40 normal subjects who had never worn SCL and 40 eyes from 40 SCL wearers who had worn lenses for more than 2 years were enrolled. Corneal epithelium over the entire cornea was topographically imaged using a novel optical coherence tomography system. An epithelial thickness map was automatically generated. Epithelial thicknesses of the central 2-mm, paracentral 2- to 5-mm (P1), and midperipheral 5- to 6-mm (P2) zones were obtained. In addition, the epithelial map variability in P1 and P2 zones, including maximum − minimum (MAX − MIN), map SD, and coefficient of variation (CV), was measured and analyzed. Results The average epithelial thickness of the central, P1, and P2 zones was 54.4 ± 1.1 &mgr;m, 53.2 ± 2.2 &mgr;m, and 52.3 ± 2.0 &mgr;m, respectively, in normal eyes and 49.2 ± 1.9 &mgr;m, 48.8 ± 2.2 &mgr;m, and 48.7 ± 2.8 &mgr;m, respectively, in eyes wearing SCL. Compared with normal control subjects, eyes with long-term SCL had significantly thinner epithelial thickness in all three zones (p < 0.05). However, there was no difference in MAX − MIN, SD, and CV of P1 and P2 zones between two groups. In both groups, there was significant difference in the epithelial thickness among different sectors in the paracentral and midperipheral zones. Conclusions There is a decrease in epithelial thickness in subjects who wear SCL long term. Clinicians should take note of the nonuniformity of the paracentral and midperipheral corneal epithelium thicknesses. This method may be useful for detecting early changes in corneal epithelial thickness caused by long-term SCL wear.

Assessment of corneal epithelial thickness in dry eye patients.

Purpose To investigate the features of corneal epithelial thickness topography with Fourier-domain optical coherence tomography (OCT) in dry eye patients. Methods In this cross-sectional study, 100 symptomatic dry eye patients and 35 normal subjects were enrolled. All participants answered the ocular surface disease index questionnaire and were subjected to OCT, corneal fluorescein staining, tear breakup time, Schirmer 1 test without anesthetic (S1t), and meibomian morphology. Several epithelium statistics for each eye, including central, superior, inferior, minimum, maximum, minimum − maximum, and map standard deviation, were averaged. Correlations of epithelial thickness with the symptoms of dry eye were calculated. Results The mean (±SD) central, superior, and inferior corneal epithelial thickness was 53.57 (±3.31) &mgr;m, 52.00 (±3.39) &mgr;m, and 53.03 (±3.67) &mgr;m in normal eyes and 52.71 (±2.83) &mgr;m, 50.58 (±3.44) &mgr;m, and 52.53 (±3.36) &mgr;m in dry eyes, respectively. The superior corneal epithelium was thinner in dry eye patients compared with normal subjects (p = 0.037), whereas central and inferior epithelium were not statistically different. In the dry eye group, patients with higher severity grades had thinner superior (p = 0.017) and minimum (p < 0.001) epithelial thickness, more wide range (p = 0.032), and greater deviation (p = 0.003). The average central epithelial thickness had no correlation with tear breakup time, S1t, or the severity of meibomian glands, whereas average superior epithelial thickness positively correlated with S1t (r = 0.238, p = 0.017). Conclusions Fourier-domain OCT demonstrated that the thickness map of the dry eye corneal epithelium was thinner than normal eyes in the superior region. In more severe dry eye disease patients, the superior and minimum epithelium was much thinner, with a greater range of map standard deviation.

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.

Correlation between the existence of the palisades of Vogt and limbal epithelial thickness in limbal stem cell deficiency

The aims of the study were to investigate limbal epithelial thickness in subjects with limbal stem cell deficiency and to evaluate the correlation between the palisades of Vogt and limbal epithelial thickness.

Optical Coherence Tomography Assessment of Angle Anatomy Changes After Trabeculectomy in Primary Angle-Closure Glaucoma.

Purpose:Using anterior chamber optical coherence tomography to evaluate changes in angle anatomy in patients with primary angle-closure glaucoma (PACG) before and after trabeculectomy. Methods:This is a prospective observational study in 38 eyes of 38 patients with PACG, who underwent trabeculectomy. We used customized software to analyze optical coherence tomography images (Visante) of all participants before and after the surgical treatment. Multivariate linear regression analysis was performed for predictors of percentage change in mean angle parameters, including scleral spur angle, angle opening distance, angle recess area, and trabecular-iris surface area. The main outcome measures were changes in angle parameters and their relationship with age, sex, refraction, MD, visual outcomes, central corneal thickness, axial length of eye, number of glaucoma bottles, baseline intraocular pressure (IOP), and percentage changes in IOP (&Dgr;IOP). Results:There was a significant increase in all angle parameters at the follow-up examination compared with the baseline value (all P<0.001). After multivariate analysis, the only variable related to changes in all angle parameters was &Dgr;IOP. Conclusions:Trabeculectomy results in a significant increase in the angle width in PACG. The increase in angle parameters was significantly related to the IOP changes.

Novel Therapy for Primary Canaliculitis: A Pilot Study of Intracanalicular Ophthalmic Corticosteroid/Antibiotic Combination Ointment Infiltration

AbstractIn patients with primary canaliculitis, conservative medical therapy is associated with a high recurrence rate. Surgical treatments carry a great resolution rate but sometimes can result in the lacrimal pump dysfunction and canalicular scarring. The aim of this study is to introduce a minimally invasive approach, intracanalicular ophthalmic corticosteroid/antibiotic combination ointment infiltration (IOI, intracanalicular ointment infiltration), and to report our preliminary results for treating primary canaliculitis.In this retrospective, interventional case series, 68 consecutive patients with newly developed primary canaliculitis at a major tertiary eye center between January 2012 and January 2015. Thirty-six patients received conservative medical treatment alone (group 1; 36 eyes). Twenty-two patients and 10 medically uncontrolled patients from group 1 underwent IOI therapy (group 2; 32 eyes). Ten patients and 26 recurrent patients from group 1 and group 2 underwent surgery (group 3; 36 eyes). Patients were followed-up for at least 8 weeks. Clinical characteristics and outcomes were analyzed and compared.In this study, patients’ age, sex, onset location, and durations of disease among 3 groups showed no significant difference. The resolution rate in group 2 was 72.7% (16/22) for new patients and 68.8% (22/32) for gross patients, respectively, both of which are higher than that of group 1 (22.2%, 10/36) but lower than that of group 3 (100%, 36/36). Of group 3, 2 patients received 2 surgical interventions and resolved finally. Microbiological workup was available in 51 patients. The most common isolates were staphylococcus species (27.9%) and streptococcus species (20%). Canalicular laceration developed in 1 patient during the IOI procedure and 1 patient undergoing surgery. Only 2 had postoperative lacrimal pump dysfunction and 1 had canalicular scarring in group 3.The IOI may be an effective and minimally invasive technique for treating primary canaliculitis and obviate the need for further intensive surgery.

Combined Lacrimal Passage Probing and Tobramycin/Dexamethasone Ophthalmic Ointment Infiltration: A Minimally Invasive Surgical Procedure for Incomplete Nasolacrimal Duct Obstruction

AbstractThe optimal treatment strategy for an incomplete nasolacrimal duct obstruction (INDO) is still being debated. The aim of this study is to evaluate the treatment results of combined lacrimal passage probing and tobramycin/dexamethasone ophthalmic ointment infiltration (PIO, Probing and Injection) for INDO.In this retrospective, noncomparative case series, 397 consecutive adult patients with INDO treated at Shanghai Eye, Ear, Nose and Throat Hospital were enrolled. Records of the patients were reviewed. With the help of a modified 23-gauge lacrimal cannula, the PIO surgery was performed for the INDO-identified patients. The main outcome measures were resolution of tearing and complications. The relationship between successful outcome and clinical characteristics was analyzed.The surgery was performed successfully in all of the enrolled cases. No intraoperative complications were found in the procedure. The average follow-up time was 7.9 months. Three hundred patients (75.6%) experienced complete resolution of their symptoms after the surgery. Ninety-seven patients (24.4%) showed a partial improvement (1.8%), no improvement (18.4%), or a worsening of symptoms (4.3%). Of the 97 surgical-failure patients, 90 required silicone intubation or external dacryocystorhinostomy, and 94% were finally resolved. The most common postoperative complications were mild nasal bleeding in 41 patients, drug residues in 12 patients (6 developed the complete obstruction), and a slit punctum in 8 patients. Multivariate logistic regression analysis revealed that unilateral eye onset, not having a discharge at baseline, and not having postoperative drug residues were significant factors determining successful outcome.The PIO surgery is an effective, safe, timesaving, easy-to-perform, and minimally invasive technique for treating INDO.