Scaling and maintenance of corneal thickness during aging

Corneal thickness is tightly regulated by its boundary endothelial and epithelial layers. The regulated set-point of corneal thickness likely shows inter-individual variations, changes by age, and response to stress. Using anterior segment-optical coherence tomography, we measure murine central corneal thickness and report on body size scaling of murine central corneal thickness during aging. For aged-matched mice, we find that corneal thickness depends on sex and strain. To shed mechanistic insights into these anatomical changes, we measure epithelial layer integrity and endothelial cell density during the life span of the mice using corneal fluorescein staining and in vivo confocal microscopy, respectively and compare their trends with that of the corneal thickness. Cornea thickness increases initially (1 month: 114.7 ± 3.0 μm, 6 months: 126.3 ± 1.6 μm), reaches a maximum (9 months: 129.3 ± 4.4 μm) and then reduces (12 months: 127 ± 2.9 μm, 13 months: 119.5 ± 7.6 μm, 14 months: 110.6 ± 10.6 μm), while the body size (weight) increases with age. We find that endothelial cell density reduces from 2 months old to 8 months old as the mice age and epithelial layer accumulates damages within this time frame. Finally, we compare murine corneal thickness with those of several other mammals including humans and show that corneal thickness has an allometric scaling with body size. Our results have relevance for organ size regulation, translational pharmacology, and veterinary medicine.

Ageing and ocular surface immunity

The prevalence of ocular surface immunopathologies is enhanced in the elderly. This increased prevalence has been attributed to age-related dysregulation of innate and adaptive immune system responses. Age-related changes in ocular surface immunity have similar and distinct characteristics to those changes seen in other mucosal tissues. This mini review provides a brief outline of key findings in the field of ocular ageing, draws comparisons with other mucosal tissues and, finally, discusses age-related changes in the context of immunopathogenesis of infectious keratitis and dry eye disease, two of the most common inflammatory disorders of the ocular surface.

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 Spearman's 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.

Optimising keratoplasty for Peters' anomaly in infants using spectral-domain optical coherence tomography

PURPOSE

To present in vivo anterior segment optical coherence tomography (OCT) features of infants with Peters' anomaly obtained during presurgical examination under general anaesthesia, and to evaluate the impact of OCT features on surgical decision making.

METHODS

This is a single-centre, consecutive, observational case series including 44 eyes of 27 infants with Peters' anomaly (5-18 months) undergoing keratoplasty. Medical records of patients were reviewed retrospectively. Clinical features and OCT findings, along with their impact on surgical decision-making were analysed.

RESULTS

Of 27 patients, 10 had unilateral and 17 had bilateral disease. Two patients with mild disease (three eyes) had a posterior corneal defect with leukoma (2/27, 7.4%). Twenty patients (32 eyes) with iridocorneal adhesions were classified as having moderate Peters' anomaly (20/27, 74.1%) and five patients (nine eyes) with lenticulocorneal adhesions were classified as having severe Peters' anomaly (5/27, 18.5%). The range of angle closure, anterior chamber depth and maximum iridocorneal adhesion length (all p<0.001) were significantly different among groups, indicating that they might serve as novel OCT parameters for assessing the severity of Peters' anomaly. The surgical approach in seven patients (21.2%) was altered in response to intraoperative OCT findings, which provided information regarding the anatomical structure of the anterior chamber not provided by the surgical microscope. The use of OCT prevented unnecessary cataract surgeries in five patients.

CONCLUSIONS

Our study showed that information gained from OCT under anaesthesia allows surgeons to classify type and severity of Peters' anomaly and supports surgical decision making.

Comparison of human corneal cell density by age and corneal location: an in vivo confocal microscopy study

Background

Peripheral and central regions of the cornea are optically different and have different repair capacity and pathology. For this reason, we characterized the cellular morphology and quantified the cell density of the central and peripheral regions of the cornea with age.

Methods

Eighty healthy subjects were enrolled in the study and divided into four groups according to age: A (0–19 years), B (20–39 years), C (40–59 years), and D (>60 years). In vivo confocal microscopy was used to measure the following parameters for the central and peripheral regions of the cornea: average cellular density and area of the superficial and basal epithelium; average density of the anterior and posterior keratocytes; average endothelial cell density and cellular area; percentage of hexagonal endothelial cells.

Results

Statistically significant differences between the central and peripheral cornea were observed for the cellular density of basal epithelial cells in group A. The density of keratocytes in the anterior stroma was significantly greater in the central region compared with the peripheral region in group B and group C. The percentage of hexagonal cells in the endothelial layer was significantly greater in the central region compared with the peripheral region. Age-related changes were found in peripheral basal epithelial cell density, central and peripheral endothelial cell density, and the percentage of hexagonal endothelial cells.

Conclusion

Both similarities and differences in morphology of the central and peripheral regions of the transparent cornea were observed. These observations would provide a histological basis for further studies to define its regional pathological mechanisms.

Ageing and ocular surface immunity

Foreword

It gives me pleasure to introduce the 4th edition of the EGS Guidelines. The Third edition proved to be extremely successful, being translated into 7 languages with over 70000 copies being distributed across Europe; it has been downloadable, free, as a pdf file for the past 4 years. As one of the main objectives of the European Glaucoma Society has been to both educate and standardize glaucoma practice within the EU, these guidelines were structured so as to play their part.

Glaucoma is a living specialty, with new ideas on causation, mechanisms and treatments constantly appearing. As a number of years have passed since the publication of the last edition, changes in some if not all of these ideas would be expected.

For this new edition of the guidelines a number of editorial teams were created, each with responsibility for an area within the specialty; updating where necessary, introducing new diagrams and Flowcharts and ensuring that references were up to date. Each team had writers previously involved with the last edition as well as newer and younger members being co-opted.

As soon as specific sections were completed they had further editorial comment to ensure cross referencing and style continuity with other sections.

Overall guidance was the responsibility of Anders Heijl and Carlo Traverso. Tribute must be made to the Task Force whose efforts made the timely publication of the new edition possible.

Roger Hitchings

Chairman of the EGS Foundation

www.eugs.org

The Guidelines Writers and Contributors 

Augusto Azuara Blanco

Luca Bagnasco

Alessandro Bagnis

Keith Barton

Christoph Baudouin

Boel Bengtsson

Alain Bron

Francesca Cordeiro

Barbara Cvenkel

Philippe Denis

Christoph Faschinger

Panayiota Founti

Stefano Gandolfi

David Garway Heath

Francisco Goni

Franz Grehn

Anders Heijl

Roger Hitchings

Gabor Hollo

Tony Hommer

Michele Iester

Jost Jonas

Yves Lachkar

Giorgio Marchini

Frances Meier Gibbons

Stefano Miglior

Marta Misiuk-Hojo

Maria Musolino

Jean Philippe Nordmann

Norbert Pfeiffer

Luis Abegao Pinto

Luca Rossetti

John Salmon

Leo Schmetterer

Riccardo Scotto

Tarek Shaarawy

Ingeborg Stalmans

Gordana Sunaric Megevand

Ernst Tamm

John Thygesen

Fotis Topouzis

Carlo Enrico Traverso

Anja Tuulonen

Ananth Viswanathan

Thierry Zeyen

The Guidelines Task Force 

Luca Bagnasco

Anders Heijl

Carlo Enrico Traverso

Augusto Azuara Blanco

Alessandro Bagnis

David Garway Heath

Michele Iester

Yves Lachkar

Ingeborg Stalmans

Gordana Sunaric Mégevand

Fotis Topouzis

Anja Tuulonen

Ananth Viswanathan

The EGS Executive Committee 

Carlo Enrico Traverso (President)

Anja Tuulonen (Vice President)

Roger Hitchings (Past President)

Anton Hommer (Treasurer)

Barbara Cvenkel

Julian Garcia Feijoo

David Garway Heath

Norbert Pfeiffer

Ingeborg Stalmans

The Board of the European Glaucoma Society Foundation 

Roger Hitchings (Chair)

Carlo E. Traverso (Vice Chair)

Franz Grehn

Anders Heijl

John Thygesen

Fotis Topouzis

Thierry Zeyen

The EGS Committees 

CME and Certification 

Gordana Sunaric Mégevand (Chair)

Carlo Enrico Traverso (Co-chair)

Delivery of Care 

Anton Hommer (Chair)

EU Action 

Thierry Zeyen (Chair)

Carlo E. Traverso (Co-chair)

Education 

John Thygesen (Chair)

Fotis Topouzis (Co-chair)

Glaucogene 

Ananth Viswanathan (Chair)

Fotis Topouzis (Co-chair)

Industry Liaison 

Roger Hitchings (Chair)

Information Technology 

Ingeborg Stalmans (Chair)

Carlo E. Traverso (Co-chair)

National Society Liaison 

Anders Heijl (Chair)

Program Planning 

Fotis Topouzis (Chair)

Ingeborg Stalmans (Co-chair)

Quality and Outcomes 

Anja Tuulonen (Chair)

Augusto Azuara Blanco (Co-chair)

Scientific 

Franz Grehn (Chair)

David Garway Heath (Co-chair)

Nasolacrimal recanalization as an alternative to external dacryocystorhinostomy for treating failed nasolacrimal duct intubation

To compare the surgical duration and clinical outcomes of nasolacrimal recanalization versus external dacryocystorhinostomy (DCR) in the treatment of failed nasolacrimal duct intubation.This is a retrospective, comparative, and interventional study. We evaluated the outcomes of 66 consecutive patients undergoing either nasolacrimal recanalization (n = 32) or DCR (n = 34) in a tertiary lacrimal disease referral center. Length of surgical duration, clinical outcomes, and rate of recurrence at 18 months postoperatively were compared.The mean surgical duration was 18.5 minutes (range, 15-25 minutes) for nasolacrimal recanalization and 48.2 minutes (range, 45-61 minutes) for DCR, respectively (P < 0.001). The rate of success was 84.4% in the recanalization group and 85.3% in the DCR group, respectively (P = 0.91). The time to recurrence was 2.6 ± 1.1 months in the recanalization group and 5.6 ± 2.1 months in the DCR group (P < 0.001). Five failed cases in each group received a secondary DCR surgery with the same resolution rate (40%). The absence of ocular discharge at baseline was a significant predictor for a successful outcome in the recanalization group (P = 0.04) but not in the DCR group (P = 0.63).Nasolacrimal recanalization is an effective, safe, and time-saving alternative to DCR for the treatment of failed nasolacrimal duct intubation. Clinicians should be cautious in patients with discharge.

Development of a novel CsA-PLGA drug delivery system based on a glaucoma drainage device for the prevention of postoperative fibrosis

The formation of a scar after glaucoma surgery often leads to unsuccessful control of intraocular pressure, and should be prevented by using a variety of methods. We designed and developed a novel drug delivery system (DDS) comprising cyclosporine A (CsA) and poly(lactic-co-glycolic acid) (PLGA) based on a glaucoma drainage device (GDD) that can continuously release CsA to prevent postoperative fibrosis following glaucoma surgery. The CsA@PLGA@GDD DDS was observed by field emission scanning electron microscopy and revealed an asymmetric pore structure. Thermogravimetric analysis was performed to measure the weight loss and evaluate the thermal stability of the CsA@PLGA@GDD DDS. The in vitro drug release profile of the DDS was studied using high performance liquid chromatography, which confirmed that the DDS released CsA at a stable rate and maintained adequate CsA concentrations for a relatively long time. The biocompatibility of the DDS and the inhibitory effects on the postoperative fibrosis were investigated in vitro using rabbit Tenon's fibroblasts. The in vivo safety and efficacy of the DDS were examined by implanting the DDS into Tenon's capsules in New Zealand rabbits. Bleb morphology, intraocular pressure, anterior chamber reactions, and anterior chamber angiography were studied at a series of set times. The DDS kept the filtration pathway unblocked for a longer time compared with the control GDD. The results indicate that the CsA@PLGA@GDD DDS represents a safe and effective strategy for preventing scar formation after glaucoma surgery.

Ambient air pollution, weather changes, and outpatient visits for allergic conjunctivitis: A retrospective registry study

Allergic conjunctivitis is a common problem that significantly impairs patients’ quality of life. Whether air pollution serves as a risk factor for the development of allergic conjunctivitis remains elusive. In this paper, we assess the relationship between air pollutants and weather conditions with outpatient visits for allergic conjunctivitis. By using a time-series analysis based on the largest dataset ever assembled to date, we found that the number of outpatient visits for allergic conjunctivitis was significantly correlated with the levels of NO₂, O₃, and temperature, while its association with humidity was statistically marginal. No associations between PM₁₀, PM_2.5, SO₂, or wind velocity and outpatient visits were seen. Subgroup analyses showed that sex seemed to modify the effects of humidity on outpatient visits for allergic conjunctivitis, but not for NO₂, O₃, or temperature. People younger than 40 were found to be susceptible to changes of all four parameters, while those older than 40 were only consistently affected by NO₂ levels. Our findings revealed that higher levels of ambient NO₂, O₃, and temperature increase the chances of outpatient visits for allergic conjunctivitis. Ambient air pollution and weather changes may contribute to the worsening of allergic conjunctivitis.

Transient Tear Film Dysfunction after Cataract Surgery in Diabetic Patients

PURPOSE

Diabetes mellitus is an increasingly common systemic disease. Many diabetic patients seek cataract surgery for a better visual acuity. Unlike in the general population, the influence of cataract surgery on tear film function in diabetic patients remains elusive. The aim of this study was to evaluate the tear function in diabetic and nondiabetic patients following cataract surgery.

METHODS

In this prospective, interventional case series, 174 diabetic patients without dry eye syndrome (DES) and 474 age-matched nondiabetic patients as control who underwent phacoemulsification were enrolled at two different eye centers between January 2011 and January 2013. Patients were followed up at baseline and at 7 days, 1 month, and 3 months postoperatively. Ocular symptom scores (Ocular Surface Disease Index, OSDI) and tear film function including tear film stability (tear film break-up time, TBUT), corneal epithelium integrity (corneal fluorescein staining, CFS), and tear secretion (Schirmer's I test, SIT) were evaluated.

RESULTS

In total, 83.9% of the diabetic patients (146 cases with 185 eyes) and 89.0% of the nondiabetic patients (422 cases with 463 eyes) completed all check-ups after the interventions (P = 0.095). The incidence of DES was 17.1% in the diabetic patients and 8.1% in the nondiabetic patients at 7 days after cataract surgery. In the diabetic patients, the incidence of DES remained 4.8% at 1 month postoperatively and decreased to zero at 3 months after surgery. No DES was diagnosed in nondiabetic patients at either the 1-month or 3-month follow-up. Compared with the baseline, the diabetic patients had worse symptom scores and lower TBUT values at 7 days and 1 month but not at 3 months postoperatively. In the nondiabetic patients, symptom scores and TBUT values had returned to preoperative levels at 1-month check-up. CFS scores and SIT values did not change significantly postoperatively in either group (P = 0.916 and P = 0.964, respectively).

CONCLUSIONS

Diabetic patients undergoing cataract surgery are prone to DES. Ocular symptoms and tear film stability are transiently worsened in diabetic patients and are restored more slowly than those in nondiabetic patients.

Actinobacillus actinomycetemcomitans Keratitis After Glaucoma Infiltration Surgery: A Clinical Report and Literature Review

Actinobacillus actinomycetemcomitans infection is a rare and easily misdiagnosed ocular disease. In this article, the authors report a chronic, purulent, and difficult-to-treat case of A actinomycetemcomitans keratitis following a glaucoma infiltration surgery.A 56-year-old man with a long-standing history of open-angle glaucoma in both eyes presented with a 12-week history of ocular pain, redness, and blurred vision in his right eye. He underwent a glaucoma infiltration surgery in his right eye 6 months ago. Three months postoperatively, he developed peripheral corneal stromal opacities associated with a white, thin, cystic bleb, and conjunctival injection. These opacities grew despite topical treatment with topical tobramycin, levofloxacin, natamycin, amikacin, and metronidazole eye drops.Multiple corneal scrapings revealed no organisms, and no organisms grew on aerobic, anaerobic, fungal, or mycobacterial cultures. The patient's right eye developed a severe purulent corneal ulcer with a dense hypopyon and required a corneal transplantation. Histopathologic analysis and 16S ribosomalribonucleic acid polymerase chain reaction sequencing revealed A actinomycetemcomitans as the causative organism. Postoperatively, treatment was initiated with topical levofloxacin and cyclosporine, as well as oral levofloxacin and cyclosporine. Graft and host corneal transparency were maintained at the checkup 1 month after surgery.Although it is a rare cause of corneal disease, A actinomycetemcomitans should be suspected in patients with keratitis refractory to topical antibiotic therapy. Delay in diagnosis and appropriate treatment can result in vision loss.

Association of Common Variants in LOX with Keratoconus: A Meta-Analysis

BACKGROUND

Several case-control studies have been performed to examine the association of genetic variants in lysyl oxidase (LOX) with keratoconus. However, the results remained inconclusive and great heterogeneity might exist across populations.

METHOD

A comprehensive literature search for studies that published up to June 25, 2015 was performed. Summary odds ratios (OR) and 95% confidence intervals (CI) of each single nucleotide polymorphism (SNP) were estimated with fixed effects model when I2<50% in the test for heterogeneity or random effects model when I2>50%. Publication bias was evaluated using funnel plots and Egger's test.

RESULTS

A total of four studies including 1,467 keratoconus cases and 4,490 controls were involved in this meta-analysis. SNPs rs2956540 and rs10519694 showed significant association with keratoconus, with ORs of 0.71 (95% CI: 0.63-0.80, P = 1.43E-08) and 0.77 (95% CI: 0.61-0.97, P = 0.026), respectively. In contrast, our study lacked sufficient evidences to support the association of rs1800449/rs2288393 with keratoconus across populations.

CONCLUSION

This meta-analysis suggested that two LOX variants, rs2956540 and rs10519694, may affect individual susceptibility to keratoconus, while distinct heterogeneity existed within this locus. Larger-scale and multi-ethnic genetic studies on keratoconus are required to further validate the results.

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

In 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

The 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.

Limitations of Keratoplasty in China: A Survey Analysis

Purpose

Each year, over 8,000 corneal transplantation surgeries are performed in China. Unlike developed countries, which have established standard requirements for operative experience for corneal specialists, little information exists on surgical training for keratoplasty in China. The aim of this study was to assess the keratoplasty experience of Chinese corneal specialists and to characterize their surgical patterns.

Methods

One hundred and twenty-one corneal specialists in 16 provinces (65 cities) in China were invited to complete an anonymous survey at the 2014 Chinese Corneal Society annual meeting, which consisted of questions with single or multiple-choice answers. Demographics, the number and type of keratoplasties performed, and the perceived limiting factors for performing keratoplasties were analyzed.

Results

An overwhelming 89% response rate was achieved. Of the 108 respondents, 76% worked in tertiary centers, and only 23% held a medical doctorate degree. Furthermore, 69% of the participants had received corneal fellowship training of less than one year. Only 71% were capable of keratoplasties. Among those doing keratoplasty, 68% performed less than 50 keratoplasties each year. Of the same group of keratoplasty surgeons, 88% of corneal specialists capable of keratoplasties had performed penetrating keratoplasties, 87% had performed lamellar keratoplasties, 12% had performed deep anterior lamellar keratoplasties, and 5% had performed Descemet’s stripping endothelial keratoplasties. When questioned on the reasons for the low number of keratoplasties performed in China, the respondents deemed the following factors most important: lack of surgical training (71%), a shortage of donor supply (52%), and a lack of curricula (42%). A multivariate logistic regression analysis showed that corneal transplantation capabilities are significantly associated with responders’ education levels and training time.

Conclusion

Keratoplasty surgery experience is suboptimal for Chinese corneal specialists. Penetrating and lamellar keratoplasties are the preferred surgical patterns. Our findings raise concerns about the adequacy of keratoplasty training in China.

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 μm, 53.2 ± 2.2 μm, and 52.3 ± 2.0 μm, respectively, in normal eyes and 49.2 ± 1.9 μm, 48.8 ± 2.2 μm, and 48.7 ± 2.8 μm, 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.

Pseudomonas aeruginosa keratitis misdiagnosed as fungal keratitis by in vivo confocal microscopy: a case report

Background

To report a case of non-typical Pseudomonas aeruginosa keratitis that was misdiagnosed as fungal keratitis by in vivo confocal microscopy.

Case presentation

A 37-year-old Chinese woman presented with a 2-week history of increasing pain and redness of the right eye. She was started on hourly topical fortified tobramycin and levofloxacin by the referring doctor without improvement. She denied any improvement of her symptoms and signs. On examination, she had a large central corneal ulcer extending to the peripheral cornea. Further symptoms included a satellite lesion, intense conjunctival injection and marked corneal oedema. The corneal scrape was not performed initially because of the deep infiltrate in the stroma. The patient was examined by in vivo confocal microscopy. Confocal microscopy images showed hyper-reflective, thin, and branching interlocking linear structures in the stroma that were 5–8 μm in width and 200–400 μm in length. The morphology was consistent with that of fungus. However, the histopathological examination, Gram stain, and culture of the cornea only confirmed the presence of a Pseudomonas species within the deep strom. No fungal element was found. The pathogen was sensitive to ciprofloxacin, gentamicin, levofloxacin, tobramycin and amikacin.

Conclusion

This case reports the potential for a false positive finding of fungus in Pseudomonas aeruginosa keratitis and emphasizes the importance of bacterial culture and antibiotic susceptibility testing in the management of microbial keratitis.

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) μm, 52.00 (±3.39) μm, and 53.03 (±3.67) μm in normal eyes and 52.71 (±2.83) μm, 50.58 (±3.44) μm, and 52.53 (±3.36) μm 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.

[Evaluation the change of corneal epithelium thickness after pterygium excision with conjunctival autograft transplantation by Fourier domain optical coherence tomography]

OBJECTIVE

To evaluate the change of corneal epithelial thickness after pterygium excision with conjunctival autograft transplantation by Fourier Domain Optical Coherence Tomography (FD-OCT) .

METHODS

Twenty-two patients (24 eyes) with the diagnosis of primary pterygium were enrolled. They underwent pterygium excision combined with conjunctival autograft transplantation. Twenty-five volunteers (25 eyes) served as the normal control group. FD-OCT was performed preoperatively and 1, 2, 3, 5, 7 days postoperatively to measure the thickness of corneal epithelium at 1 mm and 2 mm anterior to the nasal or temporal scleral spur. Corneal fluorescein staining was performed simultaneously. Comparisons on the thickness of corneal epithelium were made between preoperative values and postoperative ones.

RESULTS

The thickness of cornea epithelium at 1 mm anterior to the scleral spur was (43.81 ± 2.55) µm in normal subjects. At day 1 after surgery, corneal epithelial thickness at the same location was (21.28 ± 5.72) µm and then gradually increased to (39.94 ± 5.47) µm at day 7 postoperatively. All the difference on postoperative days had statistically significant (t = -17.69, -14.97, -10.63, -9.86, -3.15, P < 0.05) . The thickness of cornea epithelium at 2 mm anterior to the scleral spur was (40.50 ± 3.17) µm in normal subjects. At day 1 after surgery, corneal epithelial thickness at the same location was (24.02 ± 5.92) µm, and then gradually increased to (940.34 ± 5.69) µm at day 7 postoperatively. All the difference on postoperative days except day 7 had statistically significant (t = -12.08, -10.27, -6.18, -2.99, P < 0.05). Cornea epithelium at this location repaired sooner than that at 1 mm anterior to the scleral spur. At day 1 after surgery, corneal epithelium defect area were (39.31 ± 22.77) mm(2), and then decreased to (1.01 ± 1.72) mm(2) at 7 days (t = 6.68, 5.55, P < 0.05). At day 7 postoperative, 66.7% patients had a complete recovery of corneal epithelium with no fluorescein staining.

CONCLUSIONS

FD-OCT was the effective instrument for observing the change of limbus-peripheral cornea epithelium thickness.Within 7 days postoperatively, cornea epithelium restored almost normal. After pterygium surgery, limbus-peripheral cornea epithelium restoration showed the tendency from the central to peripheral cornea.

[Efficacies of continuous positive airway pressure on mixed sleep respiratory events in patients with sleep apnea]

OBJECTIVE

To explore the efficacies of continuous positive airway pressure (CPAP) for mixed sleep apnea (MSA) events in patients with sleep apnea.

METHODS

A total of 21 patients with sleep apnea whose MSA events >10 events/h on overnight polysomnography (PSG) were studied. They were selected from the Sleep Center, Guangzhou Institute of Respiratory Disease. Ten of them were diagnosed only by conventional polysomnography (PSG group) while the diagnosis of another 11 patients was further confirmed by diaphragm electromyogram (EMG) (EMG group). All of them were treated by CPAP titrated manually on PSG.

RESULTS

Manual CPAP titrating pressure in PSG group was (8.1 ± 2.2) cmH2O (1 cmH2O = 0.098 kPa) and it was similar to that in EMG group ((8.9 ± 1.5) cmH2O). Apnea-hypopnea index (AHI) decreased significantly after CPAP in both PSG group (6.9 (3.5, 10.2) vs 62.2 (54.7, 71.4) events/h) and EMG group (1.5 (0.5, 5.5) vs 71.3 (59.5, 79.5) events/h) (both P < 0.01). CPAP could eliminate MSA diagnosed either by conventional PSG (0.1 (0.0, 0.4) vs 29.6 (19.6, 32.4) events/h) or by diaphragm EMG (0.0 (0.0, 0.2) vs 18.1 (9.1, 19.3) events/h) (both P < 0.01).

CONCLUSION

CPAP can effectively treat MSA events in patients with sleep apnea.

Meibomian Gland Alteration in Patients with Primary Chronic Dacryocystitis: An In vivo Confocal Microscopy Study

PURPOSE

To evaluate meibomian gland (MG) alterations in patients with primary chronic dacryocystitis (PCD) by in vivo confocal microscopy (IVCM), and to correlate the finding with clinical presentation.

METHODS

Twenty-eight eyes with the diagnosis of PCD and their contralateral unaffected eyes were studied and compared with 27 normal controls. All subjects completed an Ocular Surface Disease Index questionnaire (OSDI) and underwent slit-lamp biomicroscopy examination, tear break-up time (BUT) measurements, fluorescein staining, Schirmer test I, and an IVCM examination of the MG. IVCM parameters, including the MG acinar unit density (MGAUD), periglandular inflammatory cell density (ICD), MG acinar unit longest diameter (MGALD), and MG acinar unit shortest diameter (MGASD) and their correlation with clinical data were analyzed.

RESULTS

The mean MG expressibility scores, BUT values, and staining scores were significantly worse in eyes with PCD compared with the contralateral clinically unaffected eyes and controls (p < 0.05). A significant decrease in MGAUD was observed in PCD eyes compared with the controls and the contralateral clinically unaffected eyes. Conversely, the mean ICD and MGASD values were significantly higher in the PCD eyes. There were no significant differences in mean MGALD value between the PCD eyes and the contralateral clinically unaffected eyes. In addition, there were significant changes in the IVCM parameters in the contralateral unaffected eyes compared with the controls, including MGAUD, ICD, MGALD, and MGASD. All IVCM parameters showed a strong, significant correlation with MG dropout grades, MG expressibility, fluorescein staining scores, and OSDI values (all p < 0.05).

CONCLUSIONS

Patients with unilateral PCD demonstrated significant changes in MG as compared with the contralateral clinically unaffected eyes and controls. The MG function should be closely observed in these patients.

[The study of corneal epithelial change in keratoconic eyes with Fourier-domain optical coherence tomographic pachymetry]

OBJECTIVE

To compare the corneal epithelial thickness profile in keratoconic and normal eyes with advanced Fourier-domain optical coherence tomography (OCT) and to evaluate the diagnostic efficiency of pachymetry parameters.

METHODS

Cross-sectional observational study. Twenty-five consecutive keratoconus patients (34 eyes) and 41 normal volunteers (41 eyes) in Eye & ENT Hospital of Fudan University between June 1 and July 31, 2013 were enrolled.Observations of corneal epithelial thickness and corneal thickness profiles were taken from all subjects. The epithelial pachymetry parameters were superior, inferior, inferior-superior (I-S), minimum (Min), maximum (Max), Min-Max, and central. The corneal pachymetry parameters were inferotemporal-superonasal (IT-SN), I-S, Min, Min-median, Min-Max, and central.Statistical analysis methods included Chi-square test, independent two-sample t-test, and Wilcoxon rank sum test. The diagnostic efficiency of all parameters were analyzed by receiver operating characteristic (ROC) curves and Youden index.

RESULTS

The inferior, I-S, Min, Min-Max, and central epithelial thickness averages were (50.5 ± 4.8) µm, (-2.7 ± 7.5) µm, (35.9 ± 10.7) µm, (-33.6 ± 18.9) µm, and (50.1 ± 6.8) µm in keratoconic eyes.In normal eyes, they were (54.8 ± 2.5) µm, (0.9 ± 1.3) µm, (51.4 ± 2.6) µm, (-5.7 ± 1.8) µm, and (54.7 ± 2.2) µm. Among the epithelial pachymetry parameters, Min-Max and Min showed high diagnostic efficiency for keratoconus (AUC = 0.967, 0.968; Youden index = 0.882, 0.829); inferior, I-S, and central parameters showed moderate efficiency (AUC = 0.794, 0.728, 0.715; Youden index = 0.461, 0.564, 0.565). The IT-SN, I-S, Min, Min-median, Min-Max, and central corneal thickness averages were (-82.8 ± 65.2) µm, (-72.5 ± 55.6) µm, (401.2 ± 83.8) µm, (-83.4 ± 48.2) µm, (-169.7 ± 99.4) µm, and (453.4 ± 58.6) µm in keratoconic eyes.In normal eyes, these parameters were respectively (-23.7 ± 18.5) µm, (-20.5 ± 19.8) µm, (525.4 ± 28.1) µm, (-23.1 ± 4.8) µm, (-59.2 ± 23.3) µm, and (533.4 ± 28.8) µm. Min, Min-median, and Min-Max had preferable diagnostic efficiency (AUC = 0.952, 0.938, 0.924; Youden index = 0.784, 0.829, 0.721); central, IT-SN, and I-S parameters showed moderate efficiency (AUC = 0.891, 0.877, 0.862; Youden index = 0.643, 0.707, 0.580).

CONCLUSIONS

In observation with Fourier-domain OCT, keratoconus was characterized by central and inferior epithelial thinning, increased epithelial thickness variation, central cornea thinning, increase in asymmetry, and gaps between corneal IT-SN and I-S thickness.Fourier-domain OCT was confirmed to have high speed, high resolution, and noninvasion. The pachymetry parameters showed specific strengths in diagnosis of keratoconus, especially epithelial pachymetry parameters of Min and Min-Max, and corneal pachymetry parameters of Min, Min-median and Min-Max.

[Strengthen Chinese translational medicine research in ocular surface]

Translational medicine emphasizes the application of the results of basic research to clinical practice and the solution of clinical issues through basic research. It is very important for the development direction of the medical field. Over the past decade, the translational medicine research in ocular surface disease has drawn international attention and developed rapidly. This field in China has made great progress, but overall there are still some gaps with the international advanced level. We need to establish the concept and the platform of translational research, explore scientific and effective methods, and create a whole chain to enhance our ocular research. It also requires research institutions and government departments to give full support. Finally, we need to explore a suitable way for the development of Chinese translational medical research.