Association between dryness sensation and ocular surface temperature and conjunctival blood flow in soft contact lens wearers

PURPOSE

To investigate the association between dryness, ocular surface temperature (OST), and conjunctival blood flow (CBF) in soft contact lens (SCL) wearers after airflow stimulation.

METHODS

After recruiting 21 SCL wearers (mean age, 25.3 ± 4.2 years), subjects used two different daily disposable silicone hydrogel SCLs (narafilcon A and delefilcon A lenses). On three of four measurement days, excluding the first, OST, CBF, tear meniscus height (TMH), and non-invasive tear break-up time (NIBUT) were measured after airflow stimulation at a rate of 3 m/s for 10 min. The measurements were conducted without SCLs on the first and second days, and with different SCLs on the third and fourth days. Dryness was evaluated using the visual analogue scale (VAS). These parameters were compared between the two types of SCLs, and their association with the dryness sensation was then investigated.

RESULTS

Dryness was significantly weakly correlated with OST (r = -0.375, p < 0.05) and CBF (r = 0.339, p < 0.05). TMH, NIBUT, and VAS scores for dryness with the delefilcon A lens (0.15 ± 0.05 mm, 3.7 ± 01.7 s and 29.4 ± 16.9) were significantly higher, longer, and lower, respectively, than those with the narafilcon A lens (0.12 ± 0.05 mm, 2.3 ± 1.7 s and 35.9 ± 17.0; p < 0.05, p < 0.01 and p < 0.01). The changes in the OST and CBF between with and without the delefilcon A lens (-0.36 ± 0.35 °C and 0.99 ± 0.19) were significantly small compared to the narafilcon A lens (-0.60 ± 0.42 °C and 1.11 ± 0.21; p < 0.01 for both comparisons).

CONCLUSION

Dryness was correlated with OST and CBF, which indicates that when dryness was high, OST was low and CBF was high. These results suggest that OST and CBF assessments are effective for evaluating dryness sensation.

Comparative study on the effect of hyperthermic massage and mechanical squeezing in the patients with mild and severe meibomian gland dysfunction: An interventional case series

BACKGROUND

Meibomian glands exist beneath the palpebral conjunctiva; thus, it is invisible to the naked eye without infrared imaging. This study used meibography to group patients with meibomian gland dysfunction (MGD) and assessed the effects of hyperthermic massage and mechanical squeezing in both groups.

MATERIALS AND METHODS

Patients with MGD were divided into two groups, according to the degree of meibomian gland loss: group 1, in which the sum of eyelid scores ranged from 0 to 4 (mild to moderate gland loss) and group 2, in which the sum of eyelid scores ranged from 5 to 6 (severe gland loss). Hyperthermic massage and mechanical squeezing were given to both groups once a week for 4 weeks, and only non-preservative artificial tears were allowed. Ocular surface disease index (OSDI), Schirmer's test, meibography score, tear break-up time (TBUT), ocular surface staining, expressible meibomian gland, and quality before and after treatment were compared.

RESULTS

Of the 49 patients who completed the 4 weeks of treatment and the evaluation at week 5, 29 were assigned to group 1 and 20 were assigned to group 2. Meibography scores, OSDI, TBUT, and expressibility of meibum had significant differences before and after treatments in both groups. However, there was no significant difference between the changes in clinical signs between group 1 and 2 after treatment. Without grouping, all patients showed significant decreases in meibography score, OSDI, cornea staining score, and increases in TBUT and expressibility of meibum after treatment.

CONCLUSIONS

Considering the results of the current study, hyperthermic massage and mechanical squeezing may be effective in patients with meibomian gland loss, regardless of the degree of severity.

Conjunctival reconstruction via enrichment of human conjunctival epithelial stem cells by p75 through the NGF-p75-SALL2 signaling axis

Severe conjunctival diseases can cause significant conjunctival scarring, which seriously limits eye movement and affects patients' vision. Conjunctival reconstruction remains challenging due to the lack of efficient methods for stem cells enrichment. This study indicated that p75 positive conjunctival epithelial cells (CjECs) were mainly located in the basal layer of human conjunctival epithelium and showed an immature differentiation state in vivo. The p75 strongly positive (p75++) CjECs enriched by immuno-magnetic beads exhibited high expression of stem cell markers and low expression of differentiated keratins. During continuous cell passage cultivation, p75++ CjECs showed the strongest proliferation potential and were able to reconstruct the conjunctiva in vivo with the most complete structure and function. Exogenous addition of NGF promoted the differentiation of CjECs by increasing nuclear localization of SALL2 in p75++ CjECs while proNGF played an opposite role. Altogether, p75++ CjECs present stem cell characteristics and exhibit the strongest proliferation potential so can be used as seed cells for conjunctival reconstruction, and NGF-p75-SALL2 signaling pathway was involved in regulating the differentiation of CjECs.

Tropism, replication competence, and innate immune responses of the coronavirus SARS-CoV-2 in human respiratory tract and conjunctiva: an analysis in ex-vivo and in-vitro cultures

BACKGROUND

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in December 2019, causing a respiratory disease (coronavirus disease 2019, COVID-19) of varying severity in Wuhan, China, and subsequently leading to a pandemic. The transmissibility and pathogenesis of SARS-CoV-2 remain poorly understood. We evaluate its tissue and cellular tropism in human respiratory tract, conjunctiva, and innate immune responses in comparison with other coronavirus and influenza virus to provide insights into COVID-19 pathogenesis.

METHODS

We isolated SARS-CoV-2 from a patient with confirmed COVID-19, and compared virus tropism and replication competence with SARS-CoV, Middle East respiratory syndrome-associated coronavirus (MERS-CoV), and 2009 pandemic influenza H1N1 (H1N1pdm) in ex-vivo cultures of human bronchus (n=5) and lung (n=4). We assessed extrapulmonary infection using ex-vivo cultures of human conjunctiva (n=3) and in-vitro cultures of human colorectal adenocarcinoma cell lines. Innate immune responses and angiotensin-converting enzyme 2 expression were investigated in human alveolar epithelial cells and macrophages. In-vitro studies included the highly pathogenic avian influenza H5N1 virus (H5N1) and mock-infected cells as controls.

FINDINGS

SARS-CoV-2 infected ciliated, mucus-secreting, and club cells of bronchial epithelium, type 1 pneumocytes in the lung, and the conjunctival mucosa. In the bronchus, SARS-CoV-2 replication competence was similar to MERS-CoV, and higher than SARS-CoV, but lower than H1N1pdm. In the lung, SARS-CoV-2 replication was similar to SARS-CoV and H1N1pdm, but was lower than MERS-CoV. In conjunctiva, SARS-CoV-2 replication was greater than SARS-CoV. SARS-CoV-2 was a less potent inducer of proinflammatory cytokines than H5N1, H1N1pdm, or MERS-CoV.

INTERPRETATION

The conjunctival epithelium and conducting airways appear to be potential portals of infection for SARS-CoV-2. Both SARS-CoV and SARS-CoV-2 replicated similarly in the alveolar epithelium; SARS-CoV-2 replicated more extensively in the bronchus than SARS-CoV. These findings provide important insights into the transmissibility and pathogenesis of SARS-CoV-2 infection and differences with other respiratory pathogens.

FUNDING

US National Institute of Allergy and Infectious Diseases, University Grants Committee of Hong Kong Special Administrative Region, China; Health and Medical Research Fund, Food and Health Bureau, Government of Hong Kong Special Administrative Region, China.

Novel approaches to model effects of subconjunctival blebs on flow pressure to improve clinical grading systems after glaucoma drainage surgery

Clinical grading systems following glaucoma filtration surgery do not include any effects of the bleb on the intra-ocular pressure and are relatively subjective, therefore carrying the risk of inter and/or intra-observer variability. The main objective of the study is to quantify and model the effect of subconjunctival bleb on flow pressure for assessment of clinical grading following glaucoma surgery. Subconjunctival bleb was created by inserting a tube into ex vivo rabbit eyes via an ab externo approach through the anterior chamber and exiting into the subconjunctival space. Sterile dyed water was injected through the tube into the developing bleb. For the in vitro approach a silicone bleb was created by clamping a circular silicone sheet, injecting dyed water through a fixed resistance outlet tube. Photographic measurements of the bleb height, planform area and pressure were taken as a function of time. Clinical blebs were also collected over a few months. Mathematical algorithm software was used to build the bleb model. Bleb height and volume increase as pressure in the bleb increases. The bleb planform area tended to a constant determined by the section of conjunctiva prior to shunt insertion. These increases were in accordance with the bleb model developed in the Appendix. They show that the pressure in the bleb is related to the resistance of the outflow. The linearity of clinical grading systems is reviewed and a new grading approach is proposed. The pressure in the bleb has a strong dependence on bleb extent, height and a weak dependence on conjunctival thickness. The pressure in a bleb can be estimated from bleb height, radius, and flow rate inlet in agreement with the bleb flow model. These results provide support for an improved bleb categorization system.

Ant Bites Conjunctival Tissue: The ABCs of Removing an Ocular Ant Foreign Body

BACKGROUND

A variety of insect-related ocular injuries have been reported in the literature. However, no reports have been published documenting injuries resulting from exposure of the ocular surface to ants. This is surprising, given the relatively ubiquitous presence of ants. This is the first known case report to describe various techniques utilized in the removal of ants from the ocular surface.

CASE REPORT

This case report details the presentation of a distressed 24-year-old woman who presented to the Emergency Department with an ocular foreign body associated with pain and increased lacrimation. She was identified to have an ant adherent to her conjunctiva. Various techniques of removal were performed, with the ant finally removed without any trauma to underlying tissues.

CONCLUSION

This is the first case report to detail various techniques utilized in the removal of ants from the ocular surface, and discusses salient features that treating physicians should be aware of in managing patients presenting with ant bites.

Impact of blinking on ocular surface and tear film parameters

PURPOSE

To investigate the influence of blinking on tear film parameters, ocular surface characteristics, and dry eye symptomology.

METHODS

A total of 154 participants were recruited in an age, gender and ethnicity-matched cross-sectional study, of which 77 exhibited clinically detectable incomplete blinking, and 77 did not. Blink rate, dry eye symptomology, tear film parameters, and ocular surface characteristics were assessed in a single clinical session.

RESULTS

Overall, a higher proportion of participants exhibiting incomplete blinking fulfilled the TFOS DEWS II dry eye diagnostic criteria (64% versus 44%, p = 0.02), with an odds ratio (95% CI) of 2.2 (1.2-4.2) times. Participants exhibiting incomplete blinking had higher Ocular Surface Disease Index scores (18 ± 13 versus 12 ± 9, p = 0.01), and greater levels of meibomian gland dropout (41.3 ± 15.7% versus 27.5 ± 14.1%, p < 0.001). Furthermore, poorer tear film lipid layer thickness, non-invasive tear film stability, expressed meibum quality, eyelid notching, and anterior blepharitis grades were also observed in those exhibiting incomplete blinking (all p < 0.05). Blink frequency did not correlate significantly with any ocular surface parameters (all p > 0.05).

CONCLUSIONS

Incomplete blinking was associated with a two-fold increased risk of dry eye disease. The greater levels of meibomian gland dropout, as well as poorer expressed meibum quality and tear film lipid layer thickness, observed would suggest that incomplete blinking may predispose towards the development of evaporative dry eye.

Near-infrared laser thermal conjunctivoplasty

Conjunctivochalasis is a common cause of tear dysfunction due to the conjunctiva becoming loose and wrinkly with age. The current solutions to this disease include either surgical excision in the operating room, or thermoreduction of the loose tissue with hot wire in the clinic. We developed a near-infrared laser thermal conjunctivoplasty system. The system utilizes a 1460-nm programmable laser diode system as the light source. At this wavelength, a water absorption peak exists and the blood absorption is minimal, so the heating of redundant conjunctiva is even and there is no bleeding. A miniaturized handheld probe delivers the laser light and reshapes the laser into a 10 × 1 mm2 line on the working plane. A foot pedal is used to deliver a preset number of calibrated laser pulses. A fold of loose conjunctiva is grasped by a pair of forceps. The NIR laser light is delivered through an optical fiber and a laser line is aimed exactly on the conjunctival fold by a cylindrical lens. Ex vivo experiments using porcine eye was performed to investigate the induced shrinkage of conjunctiva and decide the optimal laser parameters. It was found that up to 45% of conjunctiva shrinkage could be achieved.

Dry eye disease in strabismus patients: Does eye deviation harm ocular surface?

INTRODUCTION

Dry eye disease is a multifactorial disease which affects the ocular surface system, and determines ocular discomfort symptoms and visual disturbance. Various types of ocular surgery, including strabismus one, represents a recognized cause for iatrogenic dry eye. However, it is not uncommon that strabismus patients, even not undergone to surgery, report symptoms of ocular discomfort and dryness. Hypothesis We hypothesize that two possible mechanisms may determine dry eye in strabismus patients by setting up a specific vicious circle: firstly, the increased exposure of the area of the bulbar conjunctiva located on the opposite side compared to the deviation may cause the thinning of the tear film lipid layer, with increased tear film instability; secondly, the dysfunctional lubricity secondary to the altered relationship between the eyelids and the deviated globe may cause blinking-related microtrauma, and thus inflammation and tear hyperosmolarity. These two entry points into the vicious circle of dry eye may determine a cascade of detrimental mechanisms, leading to further damage of the tear film, thus closing the disease circle.

DISCUSSION

Strabismus patients may be affected by signs and symptoms of dry eye syndrome. The increased exposure of the bulbar conjunctival area along with the dysfunctional lubricity between the eyelids and the deviated eye could be the main underlying pathophysiological mechanisms acting as entry points into the vicious circle of dry eye disease. If our hypothesis was to be confirmed, ocular surface parameters should be routinely investigated in strabismus patients, whilethe use of tear substitutes with the aim of moistening and nourishing the ocular surface could help in reducing dry eye signs and symptoms.

Custom RT-qPCR-array for glaucoma filtering surgery prognosis

Excessive subconjunctival scarring is the main reason of failure of glaucoma filtration surgery. We analyzed conjunctival and systemic gene expression patterns after non penetrating deep sclerectomy (NPDS). To find expression patterns related to surgical failure and their correlation with the clinical outcomes. This study consisted of two consecutive stages. The first was a prospective analysis of wound-healing gene expression profile of six patients after NPDS. Conjunctival samples and peripheral blood samples were collected before and 15, 90,180, and 360 days after surgery. In the second stage, we conducted a retrospective analysis correlating the late conjunctival gene expression and the outcome of the NPDS for 11 patients. We developed a RT-qPCR Array for 88 key genes associated to wound healing. RT-qPCR Array analysis of conjunctiva samples showed statistically significant differences in 29/88 genes in the early stages after surgery, 20/88 genes between 90 and 180 days after surgery, and only 2/88 genes one year after surgery. In the blood samples, the most important changes occurred in 12/88 genes in the first 15 days after surgery. Correspondence analyses (COA) revealed significant differences between the expression of 20/88 genes in patients with surgical success and failure one year after surgery. Different expression patterns of mediators of the bleb wound healing were identified. Examination of such patterns might be used in surgery prognosis. RT-qPCR Array provides a powerful tool for investigation of differential gene expression wound healing after glaucoma surgery.

Outcomes of levator advancement and Müller muscle-conjunctiva resection for the repair of upper eyelid ptosis

Both the Müller muscle-conjunctiva resection (MMCR) and levator advancement (LA) procedures can be used to manage ptosis in patients with good levator function. The aim of this article is to evaluate the efficacy and cosmetic outcomes of the two procedures. The clinical records of 29 consecutive eyelids of 26 patients undergoing MMCR and 30 eyelids of 23 patients undergoing LA were analysed. Eleven (42%) in the LA group and 9 (39%) in the MMCR group were male. The preoperative eyelid measurements were significantly different in the LA compared to the MMCR groups, in terms of palpebral aperture (PA) (6.3 vs 7.4, p = 0.01), marginal reflex distance 1 (MRD1) (-0.1 vs 1.5, p < 0.001) and levator function (LF) (12.1 vs 13.4, p = 0.03). The MRD1 1 month post-surgery was slightly less in the LA group compared to the MMCR group (2.6 vs 3.18 mm, p = 0.047) but not significantly different at months 3 and 6. The final change in MRD1 was significantly higher in the LA group (2.93 vs 1.76, p = 0.004). The MMCR group had a lower incidence of lid contour abnormalities (0% vs 20%, p = 0.01) and overcorrection (0% vs 13%, p = 0.04). There was no statistically significant difference in the rates of undercorrection in either group. Both the MMCR as well as LA procedures are effective for mild to moderate ptosis in patients with good levator function. Patients undergoing MMCR had higher success rates, better preservation of the natural lid contour, and a lower incidence of overcorrection than patients undergoing LA.

Effects of Muller's muscle-conjunctival resection for ptosis on ocular surface scores and dry eye symptoms

This article evaluates the effects of Muller's muscle-conjunctival resection (MMCR) on ocular surface scores and dry eye symptoms. Forty-six patients were enrolled in the study. Eighteen underwent bilateral upper eyelid skin excision with MMCR and 28 underwent bilateral upper eyelid skin-only excision (control group). The Salisbury Eye Evaluation Questionnaire and an ocular surface evaluation protocol consisting of Schirmer's test, tear break-up time (TBUT), fluorescein and rose bengal corneal staining were performed during the pre-operative consultation and on postoperative days 7, 30, and 90. Improvement in symptoms questionnaire scores from baseline was observed on postoperative day 90 in the blepharoplasty plus MMCR group. There was no change in questionnaire scores in patients who underwent blepharoplasty alone. No between-group difference in Schirmer's test, TBUT, or fluorescein and rose bengal staining was found at any time point. In the blepharoplasty-only (control group), the fluorescein staining score was reduced on postoperative day 30 as compared to baseline, but not on day 90. In this sample, addition of MMCR to upper eyelid blepharoplasty did not worsen ocular surface scores or dry eye symptoms.

The potential role of neuropathic mechanisms in dry eye syndromes

Dry eye syndromes can involve both nociceptive and neuropathic symptoms. Nociceptive symptoms are the normal physiological responses to noxious stimuli. Neuropathic symptoms are caused by a lesion or disease of the somatosensory nervous system and can be the result of hypersensitisation of peripheral or central corneal and conjunctival somatosensory nerves. For example, inflammation could induce neuroplastic peripheral sensitisation of the ocular surface or lid wiper and exacerbate nociceptive symptoms. Neuropathic symptoms may explain the incommensurate relation between signs and symptoms in some dry eye syndromes although absence of signs of a dry eye syndrome may also be a consequence of inappropriate methods used when examining for them. Involvement of neuropathic mechanisms may also help explain dry eye symptoms which occur in association with reduced corneal sensitivity. This review includes a discussion of the potential for ocular symptoms involving neuropathic mechanisms to contribute to psychosocial problems such as depression, stress, anxiety and sleep disorders as well as for these types of psychosocial problems to contribute to neuropathic mechanisms and dry eye syndromes. Failure to consider the possibility that neuropathic mechanisms can contribute to dry eye syndromes may reduce accuracy of diagnosis and the suitability of treatment provided. Dry eye symptoms in the absence of commensurate evidence of tear dysfunction, and unsatisfactory response to tear dysfunction therapies should prompt consideration of neuropathic mechanisms being involved. Symptoms which persist after local anaesthetic instillation are more likely to be neuropathic in origin. Reducing inflammation may help limit any associated neuroplastic hypersensitivity.

[A preliminary study on the role of substance P in histamine-nasal-spray-induced allergic conjunctivitis in guinea pigs]

OBJECTIVE

To investigate the effect of the non adrenergic non cholinergic nerve (NANC) and substance P (SP) in allergic rhinoconjunctivitis by observing histamine nasal provocation induced conjunctivitis in guinea pigs.

METHODS

Forty male guinea pigs were randomly divided into five groups with each group consisting of eight guinea pigs. All anesthetized guinea pigs were exposed either to histamine (0.2%, 5 µl) (group B~E) or saline (5 µl, group A) via unilateral nostril. No pretreatment was done in group A and B while pretreatment was done in groups C~E through injection into the unilateral common carotid artery with cholinergic nerve inhibitor (atropine, 1 mg/kg, group C), cholinergic nerve inhibitor plus adrenergic nerve inhibitors (atropine, 1 mg/kg, phentolamine, 1 mg/kg plus Esmolol, 1 mg/kg, group D) and cholinergic nerve inhibitor, adrenergic nerve inhibitors plus SP receptor antagonist (the same treatment with group D plus D-SP 10(-6) mol/L, 1 µl/g, group E), respectively. To assess the ipsilateral conjunctival inflammatory reaction, conjunctiva leakage with Evans blue dye assessments and HE staining of conjunctival tissues were performed. The SP expression in ipsilateral conjunctival tissue in different groups of guinea pigs were assessed by immunofluorescence and RT-PCR. The activity of eosinophils was assessed by eosinophil major basic protein 1 (MBP1) with RT-PCR, meanwhile, the activity of mast cells was assessed by tryptase with RT-PCR. SPSS 17.0 software was used to analyze the data.

RESULTS

At 30 min after nasal application of histamine, ipsilateral conjunctivitis was successfully induced as shown by the change of conjunctiva leakage and histology. The content of Evans blue in ipsilateral conjunctival tissue of group A~E was (13.78 ± 2.48), (29.62 ± 3.31), (19.03 ± 1.47), (18.42 ± 2.52), (14.83 ± 2.14) µg/ml, respectively. There was statistically significant difference between group A and B (t = -10.66, P < 0.05), group B and C (t = 7.97, P < 0.05), group C and E (t = 4.51, P < 0.05). PT-PCR assays showed the relative expression of SP mRNA in ipsilateral conjunctival tissues of group A~E was (1.00 ± 0.04), (1.61 ± 0.09), (1.26 ± 0.03), (1.27 ± 0.06), (1.08 ± 0.05), respectively. There was statistically significant difference between group A and B (t = -22.04, P < 0.05), group B and C (t = 12.93, P < 0.05), group C and E (t = 11.85, P < 0.05). The expression of tryptase of ipsilateral conjunctiva was (1.00 ± 0.01), (1.01 ± 0.05), (1.02 ± 0.17), (1.00 ± 0.14), (1.01 ± 0.20), and the expression of MBP1 was (1.00 ± 0.03), (1.02 ± 0.15), (0.94 ± 0.08), (1.01 ± 0.07), (0.98 ± 0.13) in A~E groups. There was not statistically significant difference among five groups (F value was 1.93, 0.57, both P > 0.05).

CONCLUSIONS

Histamine nasal provocation induced allergic inflammatory response of ipsilateral conjunctiva in guinea pigs. Neural factors including NANC nerves and its medium SP participated this nose-ocular reflex process. These data help to develop a more scientific clinical treatment strategy.

Changes in Conjunctival Hemodynamics Predict Albuminuria in Sickle Cell Nephropathy

BACKGROUND

Albuminuria is an early manifestation of deterioration in renal function in subjects with sickle cell disease (SCD). Hyperfiltration may be an early mechanism for kidney damage in SCD. The purpose of the current study was to determine the association between conjunctival hemodynamics and albuminuria in SCD subjects with preserved glomerular filtration rate.

METHODS

Conjunctival microcirculation imaging was performed to measure conjunctival diameter and axial blood velocity (V) in 35 SCD and 10 healthy control subjects. Albuminuria, defined as albumin excretion ratio (AER), was obtained from the medical charts. Based on the 95% CI of conjunctival V in control subjects (0.40-0.60 mm/s), SCD subjects were allocated to 3 groups: V1 <0.40 mm/s (n = 7), V2 of 0.40-0.60 mm/s (n = 18) and V3 ≥0.60 mm/s (n = 10).

RESULTS

Mean log(AER) measurements in the V1, V2 and V3 groups were 1.08 ± 0.67, 1.39 ± 0.59 and 2.00 ± 0.91 mg/g creatinine, respectively, and followed a positive linear trend from the V1 to V3 groups (p = 0.01). By multivariate linear regression analysis, conjunctival V significantly correlated with albuminuria (p = 0.01) independent of age, blood pressure, α-thalassemia, hematocrit, white blood cell count and lactate dehydrogenase concentration.

CONCLUSIONS

Increased conjunctival V is associated with albuminuria in SCD subjects. Assessment of conjunctival microvascular hemodynamics may improve our understanding of the pathophysiology and clinical management of sickle cell nephropathy.

[Ocular surface acidity and buffering system (by studying the conjunctival sac)]

As any mucous membrane the conjunctiva is characterized by a definite pH value which guarantees-physiological functioning of the ocular surface. The most commonly used method of assessment is potentiometric pH measurement with ion-specific glass microelectrodes. The results, however, can be affected by such factors, as conjunctival sac zoning, tissue acidity, epithelial trauma, and reflex tear secretion. Few data and hypotheses are available on mechanisms of maintaining the acid-base balance of the conjunctival sac (bicarbonate buffering system in particular).

OBJECTIVE

to study spatial variability of conjunctival tear fluid pH and possible mechanisms of its maintenance using original methods of acidity measurement and mineral content assessment.

MATERIAL AND METHODS

Tear pH was determined in 42 healthy participants (84 eyes) by means of litmus test strips and computer- aided colorimetry. Electron probe microanalysis in combination with energy dispersive spectrometry was performed in 8 healthy participants (8 eyes, 8 samples).

RESULTS

In the group of 42 healthy participants (84 eyes) the pH value of conjunctival tear fluid varied from 6.30 to 7.23 with the average of 6.76 and pH mode 6.74. The pH value of conjunctival mucous discharge was measured in 25 healthy participants (28 eyes) and varied from 7.00 to 8.00 with the average of 7.26 and pH mode 7.30. The main mineral components of tear fluid are chlorine, sodium, potassium, and boron. Borate buffer is regarded as a mechanism of maintaining the acid-base balance of the ocular surface.

CONCLUSIONS

The developed method of pH measurement ensuresreliable determination of conjunctival sac acidity in accordance with zoning and heterogeneity of its media as well as the complex structure of the tear film. In a healthy population, the acidity of tear significantly differs from that of conjunctival mucous discharge. Soluble chlorine, sodium, potassium, and boron compounds are the prevailing mineral components of tear fluid. Borate buffer appears to be the most stable of all mechanisms of maintaining the acid-base status of tear fluid.

Feasibility of conjunctival hemodynamic measurements in rabbits: reproducibility, validity, and response to acute hypotension

OBJECTIVE

To evaluate the feasibility of conjunctival hemodynamic measurements based on assessment of reproducibility, validity, and response to acute hypotension.

METHODS

Image sequences of the conjunctival microvasculature of rabbits were captured using a slit lamp biomicroscope under a steady-state condition, after topical administration of phenylephrine, and after intravenous administration of esmolol. Venous hemodynamic parameters (diameter, blood velocity, blood flow, and wall shear stress) were derived.

RESULTS

Conjunctival venous diameters ranged from 9 to 34 μm and blood velocities ranged from 0.08 to 0.95 mm/s. Coefficients of variation of venous diameter and blood velocity measurements were, on average, 6% and 14%, respectively. Automated and manual measurements of venous diameter and velocity were highly correlated (R = 0.97; p < 0.001; n = 16). With phenylephrine administration, diameter and velocity were reduced by 21% and 69%, respectively. Following esmolol administration, blood pressure was reduced with a concomitant decrease in velocity, followed by recovery to baseline. Venous blood velocity, flow, and WSS were correlated with blood pressure (R ≥ 0.52; p ≤ 0.01).

CONCLUSIONS

The feasibility of quantifying alterations in microvascular hemodynamics in the bulbar conjunctiva was established. The method is of potential value in evaluating microcirculatory hemodynamics related to cardiovascular function.

Concise review: limbal stem cell deficiency, dysfunction, and distress

The cornea is the clear tissue at the front of the eye that transmits light to the retina at the back of the eye. The cornea is covered by an epithelium and surrounded by a narrow band of tissue known as the limbus. The limbus has two important roles in maintaining a healthy corneal epithelium. First, stem cells for the corneal epithelium reside at the limbus and not in the cornea. Second, the limbus acts as a barrier separating the clear avascular corneal epithelium from the surrounding vascular conjunctival tissue. A failure of these limbal functions can result in the painful and blinding disease of limbal stem cell deficiency. In this disease, the corneal epithelium cannot be maintained by the stem cells, and the corneal surface becomes replaced by hazy conjunctival tissue. There are many causes of limbal stem cell deficiency, such as burns to the eye, inflammatory diseases, and hereditary diseases. Current understanding of the pathophysiology of the disease is discussed here. In particular, understanding whether the limbal stem cells are lost or become dysfunctional or indeed whether the limbal microenvironment is disturbed is important when developing appropriate management strategies for the disease.

[Potential of impression cytology in diagnosis and evaluation of efficacy of pharmacological correction of dry eye syndrome associated with contact lens wearing]

Potential of impression cytology in diagnosis and evaluation of efficacy of pharmacological correction of dry eye syndrome (DES) associated with contact lens wearing was studied. When wearing contact lenses for a long time DES with tear film instability and reduction of tear production occurs in more than 50% patients. Morphological changes of epithelium of tarsal and bulbar conjunctiva manifest consequently. Impression cytology reveals structural damage of epithelium with keratinization signs and decrease of goblet cells density down to total absence. After tear substitution therapy tear break-up time increased by 65,3% and total tear production by 11,4%. In control impression cytology of tarsal and bulbar conjunctiva during tear substitution therapy the following changes were revealed: recovery of goblet cells density and differentiation, recovery of epithelial structure and reduction of epithelium keratinization.

Diagnostic accuracy of "pallor" for detecting mild and severe anaemia in hospitalized patients

OBJECTIVE

To determine the accuracy of pallor of conjunctiva, nailbed, and palm in detecting mild and severe anaemia.

METHODS

Three hundred and five consecutive patients admitted in the medical and surgical wards of Mayo Hospital, Lahore were enrolled in the study. Conjunctiva, nailbed, and palm of patients were assessed. Mild anaemia was defined as Hb < 11.5 g/dl for females and Hb <13 g/dl for males. Severe anaemia was defined as Hb <7 g/dl. Likelihood ratios (LR) and their 95% confidence intervals (CI) for both presence and absence of pallor at each site were calculated. To compare the accuracy of different pallor sites in diagnosing severe anaemia, their areas under receiver operating characteristics curves (AUC) were compared.

RESULTS

Mild anaemia was present in 64.3% patients while severe anaemia was present in 7% patients. Presence of nailbed pallor had moderate accuracy for diagnosing mild anaemia (LR 5.6, 95% CI 4.7-6.7) while absence of pallor at nailbed, conjunctiva, and palm (LR 0.6 for all) did not rule out mild anaemia. All sites had modest accuracy for detecting severe anaemia (LR 2.5-3.0). Absence of pallor at conjunctiva (LR 0.1, 95% CI 0.03-0.5) and palm (LR 0.1, 95% CI 0.03-0.5) convincingly ruled out severe anaemia. Comparison of the AUC for different pallor sites showed that all sites were equally useful for detecting severe anaemia.

CONCLUSION

Pallor is not an accurate sign for mild anaemia. Pallor of conjunctiva, palm, and nailbed has modest accuracy in detecting severe anaemia. Absence of pallor at conjunctiva and palm convincingly rules out severe anaemia.

Corneal and conjunctival findings after mitomycin C application in pterygium surgery: an in-vivo confocal microscopy study

PURPOSE

To perform a qualitative assessment of the topical side-effects of mitomycin C on cornea after pterygium surgery.

METHODS

In-vivo confocal microscopy (Heidelberg Retina Tomograph II in combination with the Rostock Cornea Module) was performed in 10 patients with unilateral primary pterygium. Mitomycin C 0.02% was applied topically to seven eyes for 5 min intraoperatively and twice daily for 5 days postoperatively. Three eyes underwent surgery without application of cytostatic agent. Patient follow-up was 1 month.

RESULTS

After application of mitomycin C, complete epithelialization of the operated zone was found 2 weeks after surgery. In-vivo confocal microscopy revealed signs of superficial punctate keratitis for 2 weeks in the central cornea only after application of mitomycin C. The presence of epithelial and stromal oedema in this group was noted for up to 2 weeks in the central cornea and for up to 4 weeks in the operated zone. In the control group, complete epithelialization was found after 1 week; there were no signs of oedema after 1 week in the central cornea or after 2 weeks in the operated zone. Leucocyte infiltration and increased Langerhans cell density were noted in both groups in the operated and central zones. Analysis of the conjunctiva revealed a decrease in goblet cell density following cytostatic application.

CONCLUSION

Local application of mitomycin C delays corneal epithelialization, and prolongs postoperative epithelial and stromal oedema in both the centre and periphery. Moreover, signs of punctate keratitis were noted 2 weeks after surgery in central intact cornea. Nevertheless, in-vivo confocal microscopy shows that these changes are reversible 4 weeks after application of mitomycin C 0.02%.

Evaluating subconjunctival bleb function after trabeculectomy using slit-lamp optical coherence tomography and ultrasound biomicroscopy

BACKGROUND

The existing classifications for evaluating glaucoma filtering blebs rely mostly on external bleb characteristics and the postoperative control of intraocular pressure (IOP). Internal bleb structures are not carefully observed. This study aimed to analyze and compare glaucoma filtering bleb morphology using slit-lamp-adapted optical coherence tomography (SL-OCT) and ultrasound biomicroscopy (UBM), and to classify blebs according to results and intraocular pressure.

METHODS

We followed 29 eyes of 21 male patients and 40 eyes of 32 female patients who underwent glaucoma filtering surgery in Sixth People's Hospital of Shanghai, between 2002 and 2006. The blebs were imaged using SL-OCT and UBM and classified according to the intrableb morphology and control of IOP after surgery. A Fisher's exact test was used to compare the sensitivity for predicting a functioning bleb differed significantly between SL-OCT and UBM. A Fisher's exact test was also used for morphological analysis of the trabeculectomy blebs based on SL-OCT.

RESULTS

In the 69 eyes, there were 45 (65.2%) functioning blebs and 24 (34.8%) non-functioning blebs. We classified the blebs into four categories on the basis of SL-OCT images: diffuse, cystic, encapsulated and flat. Diffuse and cystic blebs were typically functional, whereas the other two types were always non-functional. The sensitivity of SL-OCT for predicting a functioning bleb was 92.7% (38/41 eyes) and specificity of predicting a non-functioning bleb was 83.3% (20/24 eyes). By contrast, sensitivity of UBM was 66.7% (30/45 eyes) and specificity was 75.0% (18/24 eyes). The sensitivity for predicting a functioning bleb differed significantly between the two techniques (P = 0.003).

CONCLUSIONS

SL-OCT provides high-axial-resolution images of anterior segment structures. The non-contact approach of SL-OCT enables visualization of intrableb structures at any time after surgery. SL-OCT has greater sensitivity and specificity than UBM in evaluating filtering bleb function. The morphological classification supported the assessment of bleb function and could provide objective data for evaluating the outcome of antiglaucoma surgery or the need for a second procedure.

The differences of tear function and ocular surface findings in patients with atopic keratoconjunctivitis and vernal keratoconjunctivitis

BACKGROUND

The pathogenesis of the ocular surface disease in atopic keratoconjunctivitis (AKC) and vernal keratoconjunctivitis (VKC) has not been fully understood. We tried to clarify the differences in the ocular surface status in patients with AKC, VKC, and healthy control subjects.

METHODS

Twenty-four eyes of 12 AKC patients, 12 eyes of six VKC patients, and 20 eyes of 10 normal control subjects were studied. The subjects underwent corneal sensitivity measurements, Schirmer test, tear film break-up time (BUT), vital staining of the ocular surface, conjunctival impression and brush cytology. Impression cytology samples underwent periodic acid Schiff staining for goblet cell density, squamous metaplasia grading, and immunohistochemical staining for MUC1, 2, 4, and 5AC. Brush cytology specimens underwent staining for inflammatory cell counting and Real Time PCR for MUC1, 2, 4, and 5AC mRNA expression.

RESULTS

The mean BUT, corneal sensitivity, and conjunctival goblet cell density values in AKC patients were significantly lower compared with VKC patients and control subjects. The squamous metaplasia grades in eyes with AKC were significantly higher compared to eyes with VKC and controls. The inflammatory cell response in brush cytology specimens was different between patients with AKC and VKC. Eyes with AKC showed significantly higher MUC1, 2 and 4 and lower MUC5AC mRNA expression compared to eyes with VKC.

CONCLUSIONS

Differences of the infiltrates, higher level of tear instability, lower corneal sensitivity, up-regulation of MUC1, 2, and 4, and down regulation of MUC5AC were important differential features of the ocular surface disease in AKC compared with VKC.

Tear function and ocular surface changes in multinodular goiter patients

AIMS

To evaluate preoperative and postoperative conjunctival surface changes in multinodular goiter (MNG) patients and to compare their results with healthy control subjects.

METHODS

Twenty MNG patients who had undergone near total thyroidectomy were evaluated pre- and postoperatively at the end of the 3rd month and the 1st year by performing tear function tests and conjunctival impression cytologic analysis. These results were compared with the results of 15 healthy volunteers.

RESULTS

When preoperative and postoperative tear function parameters were compared, the mean Schirmer test value and BUT value were decreased, the mean Rose Bengal staining score was increased during the postoperative period. These differences were statistically significant at the end of the 1st year (p < 0.001). The average goblet cell density of the MNG patients decreased significantly during the postoperative period when compared with the preoperative values (p < 0.001). All these findings of the MNG cases were significantly different from the results of the control group both before and after the operation.

CONCLUSION

Tear function tests and the impression cytology findings of the MNG cases were statistically different from the results of the control group during the pre- and postoperative period. We recommend postoperative follow-up of these patients for ocular surface changes.

Nerve growth factor has a modulatory role on human primary fibroblast cultures derived from vernal keratoconjunctivitis-affected conjunctiva

PURPOSE

To evaluate the role of nerve growth factor (NGF) in remodeling processes of vernal keratoconjunctivitis (VKC). VKC is a chronic inflammatory disorder of the conjunctiva and is characterized by marked tissue remodeling. NGF, a pleiotrophic factor with documented profibrogenic activities, is produced by inflammatory and structural cells populating the VKC conjunctiva and is increased in the serum and tears of VKC patients.

METHODS

Primary cultures of VKC-derived fibroblasts (VKC-FBs) were exposed to increasing NGF concentrations (1-500 ng/ml) to evaluate and compare the expression of alpha-smooth muscle actin (alphaSMA, a defining myofibroblast marker), collagens (types I and IV), and metalloproteinases and tissue inhibitors (MMP9/TIMP1, MMP2/TIMP2) at the biochemical as well as molecular levels.

RESULTS

Endogenous NGF was increased in the VKC-FB supernatant, as compared to healthy-FB supernatant. VKC-FBs expressed alphaSMA and increased types I and IV collagens. VKC-FBs, and in particular all alphaSMA positive cells, expressed both trkA(NGFR) and p75(NTR), while healthy-FBs only expressed trkA(NGFR). Exogenous NGF did not change alphaSMA expression, while alphaSMA expression was enhanced by specific neutralization of p75(NTR). NGF (10 ng/ml) exposure significantly decreased type I collagen expression, without affecting type IV collagen, and increased MMP9mRNA and protein.

CONCLUSIONS

The autocrine modulation of differentiation and response of VKC-FBs to NGF exposure with downregulation of type I collagen and upregulation of MMP9 expression supports a relevant role for NGF in tissue remodeling of VKC.

Comparing FAMACHA eye color chart and Hemoglobin Color Scale tests for detecting anemia and improving treatment of bovine trypanosomosis in West Africa

African animal trypanosomosis (AAT) is considered the most important cattle disease in sub-Saharan Africa but its diagnosis in the field is difficult, resulting in inappropriate treatments, excessive delay in treatments and under-treatment. A field study in West Africa investigated the usefulness of anemia in the diagnosis of trypanosomosis. A total of 20,772 cattle blood samples were taken from 121 villages in 3 countries. The average packed cell volume (PCV) of trypanosomosis positive cattle was 23%, versus 28% for negative cattle. In a sub-set of animals, other causes of anemia were investigated showing most of the anemia burden was attributable to trypanosomosis. Anemia was a reasonably accurate indicator of trypanosomosis in the study area, with a sensitivity of 56% and a specificity of 80% and a diagnostic odds ratio of 4.2, the highest of all the signs evaluated (anemia, emaciation, staring coat, lymphadenopathy, fever, lacrimation and salivary or nasal discharge). Having confirmed the usefulness of anemia as a predictor of trypanosomosis, two potential pen-side tests for anemia were evaluated (the first reported trial of their use in cattle), firstly a color chart developed for anemia detection in sheep through visual inspection of conjunctival membranes (FAMACHA) and secondly the Hemoglobin Color Scale (HbCS) developed for assessing hemoglobin levels in human patients by comparing blood drops on filter paper with color standards. In a population of cattle suspected by their owners to be sick with trypanosomosis (n=898) the sensitivity of the HbCS test was 56% and the specificity was 77%, while the sensitivity of the FAMACHA test was 95% and the specificity was 22%. The higher sensitivity but lower specificity suggests the FAMACHA may be useful as a screening test and the HbCS as a confirmatory test. The two tests were also evaluated in cattle randomly selected from the village herd. Using cut-off points to optimize test performance, the HbCS test had a sensitivity of 81% and a specificity of 62% (n=505 cattle), while the FAMACHA had a sensitivity of 92% and a specificity of 30% (n=298 cattle). Recommendations are made for the appropriate use of these tests in the West African region.

Accuracy of the FAMACHA system for on-farm use by sheep and goat producers in the southeastern United States

FAMACHA is a practical on-farm system designed to provide small ruminant producers a tool for improving their management of Haemonchus contortus infections. Although this system has become very popular and widely accepted by small ruminant producers in many regions of the southern United States, there is very limited data reported on the effectiveness of the FAMACHA system when performed by farmers. The objective of this study was to evaluate the accuracy of the FAMACHA system for on-farm use by small ruminant producers during the summer season. Small ruminant producers from Georgia, Louisiana, Florida, and Puerto Rico were trained to use the FAMACHA system by veterinarians and scientists experienced with this method. FAMACHA scores were assigned at least every 2 weeks by producers to weaned and mature sheep (n=552) and goats (n=676) of various breeds and ages between April and September 2004. At intervals that varied among farms from 2 to 8 weeks, researchers determined body condition scores (BCS; 1=thin and 5=fat) and collected blood and feces from a group of animals selected randomly to determine packed cell volume (PCV) and fecal egg counts (FEC). Two separate anemia thresholds were evaluated; these were defined by either FAMACHA score (>or=3 versus >or=4) or PCV (<or=19 versus <or=15%). The correlation between FAMACHA scores and PCV or FEC was high for both sheep and goats (P<0.001). Specificity was maximized when FAMACHA scores of 4 and 5 were considered anemic, but sensitivity was low. Sensitivity for detecting anemic animals was 50% for sheep and 89% for goats when eye score values of >or=3 were considered anemic and PCV cutoff was <or=15%. The percentage of false negatives (anemic animals not identified by FAMACHA evaluation) was less than 5% in sheep and less than 1% in goats when FAMACHA scores>or=3 were considered anemic and PCV cutoff was <or=15%. In both sheep and goats, predictive value of a negative was greater than 90% for all anemia and eye score categories. These data indicate that the FAMACHA method used by producers is a valuable tool for identifying anemic sheep and goats in the southern United States and Puerto Rico.

Ocular surface and intraocular inflammation are related in SS-I and rheumatoid arthritis patients

The purpose of this study is to evaluate the intraocular inflammation at a sub clinical level, in patients suffering from Sjogren's syndrome (SS-I) and Rheumatoid Arthritis (RA), to relate it with the ocular surface status and to verify the diagnostic performance of the method. Twenty-eight patients suffering from SS-I, 31 patients suffering from RA and 31 normal subjects matched in age and gender were included in the study. A Kowa 500F laser cell flare meter was utilized to quantify the aqueous cells and flare in vivo, ocular surface inflammation was graded by conjunctival cytology and dosage of serum albumin in tears, eye dryness was scored with Tear Function Index. All data resulted significantly different in both SS-I and RA patients vs. control group and also different comparing SS-I vs. RA patients group, except for the Flare values. A blood-aqueous barrier breakdown occurs either in SS-I and RA patients; the degree of the damage is related with ocular surface inflammation and dryness. We recommend the aqueous flare be analysed in those rheumatic patients where an ocular surface inflammation has been documented.

Betamethasone and Improvement of Neurological Symptoms in Ataxia-Telangiectasia

BACKGROUND

To our knowledge, there have been no reports on the control of central nervous system symptoms in patients with ataxia-telangiectasia.

OBJECTIVE

To preliminarily determine the effectiveness of corticosteroid therapy on the central nervous system symptoms of a child with ataxia-telangiectasia in whom neurological signs improved when, occasionally, he was given betamethasone to treat asthmatic bronchitis attacks.

DESIGN

Case report.

SETTING

Tertiary care hospital. Patient A 3-year-old boy with the classic hallmarks and a proved molecular diagnosis of ataxia-telangiectasia.

INTERVENTIONS

We used betamethasone, 0.1 mg/kg per 24 hours, divided every 12 hours, for 4 weeks to preliminarily determine its effectiveness on the child's central nervous system symptoms and its safety. Methylprednisolone, 2 mg/kg per 24 hours, divided every 12 hours, was then given in an attempt to perform a long-term treatment.

RESULTS

There were improvements in the child's neurological symptoms 2 or 3 days after the beginning of the drug treatment. After 2 weeks of treatment, the improvement was dramatic: the disturbance of stance and gait was clearly reduced, and the control of the head and neck had increased, as had control of skilled movements. At 4 weeks of treatment, adverse effects mainly included increased appetite and body weight and moon face. No beneficial effect was obtained when, after 4 weeks, betamethasone was replaced with methylprednisolone. Six months later, without therapy, the child continued to experience severe signs of central nervous system impairment.

CONCLUSION

Controlled studies to better understand the most appropriate drug and therapeutic schedule are required.

Comparison of topical steroids for acute anterior uveitis

This study objectively compares efficacy of dexamethasone Na phosphate 0.1%, fluorometholone 0.1% (FML), loteprednol etabonate 0.5% (Lotemax [LE]; Bausch & Lomb Pharmaceuticals, Inc., Tampa, FL), prednisolone acetate 1% (Pred Forte [PRED F]; Allergan Pharmaceuticals, Irvine, CA), and generic prednisolone acetate 1% (PRED A). These steroids were administered for 24 hours or 72 hours to New Zealand white rabbits with endotoxin-induced uveitis. Intraocular pressure (IOP), slit-lamp examination, and confocal microscopy were performed daily. Internalization of the glucocorticoid receptor (GC) was assayed in iris tissue by Western blot, and protein in aqueous humor by Bradford assay. Only LE and PRED F treatments significantly internalized GC receptor after 72 hours of treatment. Only LE and PRED A reduced protein concentration between 24 hours and 72 hours of treatment. All drugs improved clinical signs after 24 hours of treatment. None of the steroids promoted return of the inflammation-induced corneal thickness to baseline. While none returned IOP to baseline, LE was most effective. Confocal microscopy indicated that only treatment with LE reverted the abnormal endothelial-cell shape to normal. In conclusion, all steroid treatments reduced uveitis to some degree but LE was consistently effective. A longer observation period may be required to document the return of IOP and corneal thickness to baseline values.

The impact of the onset time of atopic keratoconjunctivitis on the tear function and ocular surface findings

PURPOSE

To investigate the tear and ocular surface findings between controls, children, and adults with atopic keratoconjunctivitis (AKC).

DESIGN

Prospective comparative study.

METHODS

Twenty eyes of 10 childhood-onset, 10 eyes of five adult-onset, AKC adult patients, and 12 eyes of six children with infantile-onset AKC, 14 eyes of seven normal adults and seven normal children were recruited. Corneal aesthesiometry, Schirmer test, tear film break-up time (BUT), vital staining, and conjunctival impression cytology were performed.

RESULTS

The Schirmer and Rose Bengal scores in childhood-onset adult AKC patients were considerably worse than adult-onset adult AKC patients, pediatric subjects, and the controls (P < .05). The same significant relation was observed in impression cytology parameters.

CONCLUSIONS

Ocular surface disease in childhood-onset adult AKC patients was characterized by greater ocular surface epithelial damage. Prolonged inflammation may be important in the evolution and progression of ocular surface disease in patients with longstanding active AKC.

Accuracy of clinical pallor in the diagnosis of anaemia in children: a meta-analysis

BACKGROUND

Anaemia is highly prevalent in children of developing countries. It is associated with impaired physical growth and mental development. Palmar pallor is recommended at primary level for diagnosing it, on the basis of few studies. The objective of the study was to systematically assess the accuracy of clinical signs in the diagnosis of anaemia in children.

METHODS

A systematic review on the accuracy of clinical signs of anaemia in children. We performed an Internet search in various databases and an additional reference tracking. Studies had to be on performance of clinical signs in the diagnosis of anaemia, using haemoglobin as the gold standard. We calculated pooled diagnostic likelihood ratios (LR's) and odds ratios (DOR's) for each clinical sign at different haemoglobin thresholds.

RESULTS

Eleven articles met the inclusion criteria. Most studies were performed in Africa, in children underfive. Chi-square test for proportions and Cochran Q for DOR's and for LR's showed heterogeneity. Type of observer and haemoglobin technique influenced the results. Pooling was done using the random effects model. Pooled DOR at haemoglobin <11 g/dL was 4.3 (95% CI 2.6-7.2) for palmar pallor, 3.7 (2.3-5.9) for conjunctival pallor, and 3.4 (1.8-6.3) for nailbed pallor. DOR's and LR's were slightly better for nailbed pallor at all other haemoglobin thresholds. The accuracy did not vary substantially after excluding outliers.

CONCLUSION

This meta-analysis did not document a highly accurate clinical sign of anaemia. In view of poor performance of clinical signs, universal iron supplementation may be an adequate control strategy in high prevalence areas. Further well-designed studies are needed in settings other than Africa. They should assess inter-observer variation, performance of combined clinical signs, phenotypic differences, and different degrees of anaemia.

Increased expression of advanced glycation end-products and their receptor, and activation of nuclear factor kappa-B in lacrimal glands of diabetic rats

AIMS/HYPOTHESIS

To assess the involvement of the AGE-specific receptor (AGER, also known as RAGE) axis and nuclear factor kappa-B (NFKB, also known as NF-kappaB) activation in the development of lacrimal gland and tear film dysfunction in diabetes, the present study evaluated: (1) lacrimal gland and tear film alterations in diabetic rats; and (2) the expression of AGE, AGER and NFKB in ocular tissues of normoglycaemic and diabetic rats.

MATERIALS AND METHODS

Diabetes was induced in male Wistar rats with intravenous streptozotocin. Tear secretion parameters were measured and NFKB expression was evaluated in lacrimal glands of control and diabetic rats by western blot. Immunohistochemistry with confocal microscopy was used to assess AGE, AGER and NFKB expression in lacrimal glands of both groups.

RESULTS

Lacrimal gland weight and tear film volume were lower in diabetic than in control rats (p=0.01 and 0.02, respectively). IL1B and TNF concentrations in tears were higher in diabetic than in control rats (p=0.007 and 0.02, respectively). NFKB protein was identified in rat cornea, conjunctiva and lacrimal glands. AGE, AGER and NFKB expression were greater in lacrimal glands of diabetic than in those of control rats.

CONCLUSIONS/INTERPRETATION

Diabetes induces significant alterations in rat lacrimal gland structure and secretion. The higher expression of AGE, AGER and NFKB in lacrimal glands of diabetic rats suggests that these factors are involved in signalling and in subsequent inflammatory alterations related to dry eye in diabetes mellitus.

Clinical Impact of Conjunctivochalasis on the Ocular Surface

PURPOSE

To report the clinical impact of conjunctivochalasis on the ocular surface by evaluating the effect of a new concept of conjunctivochalasis operation on the resolution of patients' symptoms and corneal epithelial damage. Also, the association of inflammation with conjunctivochalasis is examined.

PATIENTS AND METHODS

A total of 168 eyes of 131 conjunctivochalasis patients with (50 eyes) or without (118 eyes) dry eye who received the newly designed conjunctivochalasis operation were enrolled. All patients had prominent conjunctivochalasis at the lower tear meniscus and their ocular symptoms were not sufficiently controlled by the usual eyedrop therapy. Subjective symptoms of patients were assessed before and after the operation by questionnaires. Scores of corneal fluorescein staining were evaluated before and after the operation in patients with dry eye. Four samples of the lower part of conjunctiva from non-dry eye conjunctivochalasis patients were investigated by immunostaining and compared with samples from 4 normal conjunctiva and 3 conjunctiva showing inflammation due to Mooren ulcer, ocular cicatricial pemphigoid, and alkali burn.

RESULTS

The most frequent chief subjective symptoms before the operation were irritation (51.7%) and lacrimation (31.4%) in conjunctivochalasis patients without dry eye and irritation (80.0%) in those with dry eye. Improvement of the chief symptoms was obtained in 88.2% and 78.0% of these 2 patient groups, respectively. Furthermore, in patients with dry eye, corneal fluorescein staining scores (mean+/-SD) were significantly improved after the operation compared with before the operation: A (area), 0.6+/-0.7 and D (density), 0.8+/-0.9 versus A, 1.3+/-0.5 and D, 1.9+/-0.9; P<0.0001. Based on the immunostaining study, conjunctival samples from eyes with conjunctivochalasis and normal eyes showed negligible inflammation compared with those from inflamed conjunctiva.

CONCLUSIONS

This study suggests that conjunctivochalasis has a great clinical impact on the ocular surface, and the newly developed operation is very effective in resolving patient complaints and also ocular surface damage in conjunctivochalasis with dry eye. It may also be suggested that the conjunctivochalasis has a negligible association with conjunctival inflammation.

[Experimental study on mechanism of recompression therapy of decompression sickness]

OBJECTIVE

To elucidate that recompression is the most efficient measure in removing the pathogenic factors.

METHOD

When rabbits were suffering from severe DCS, their pressure were immediately compressed to 0.5 Mpa. Precordial region was monitored continuously with a Doppler flow meter, micrography of the bulbar conjunctiva was done intermittently and the behaviors of the animals were recorded.

RESULT

Effects of therapeutic recompression and elimination of circulating bubbles were correlated to rate and extent of recovery of microvascular function. The animals' DCS with severe dysfunction or failure of blood vessels, DCS became worse owing to progressive impairment of microvascular function during recompression and decompression.

CONCLUSION

The pressure could only cancel the tension provoked by supersaturated gas in the blood so as to relieve the spasm of the compensatory blood vessels, which can restore the blood circulation and reverse the developing course of the DCS. The pressure, however, couldn't recover the function of the blood vessels with severe dysfunction or failure, or repair the injured tissues, or eliminate the circulating bubbles directly.

Basic science and pathophysiology of ocular allergy

Ocular allergy includes several clinical subtypes ranging from the mild seasonal allergic conjunctivitis to the potentially sight-threatening atopic keratoconjunctivitis. Current therapies, particularly for the severe forms of disease, need to be more localized and with fewer side effects. For this to be achieved, it requires a better understanding of the basic mechanisms involved. In this chapter, recent findings are discussed that suggest that it is important to take an integrated approach, including both immune and structural elements of the eye. This provides potential new strategies for therapy, addressing the influence of structural cells in disease. These might influence the immune processes that take place and, as the structural cells are precisely localized, topical application is likely to be effective.

Autonomic features in cluster headache. Exploratory factor analysis

The objective is to identify the pathogenesis of each autonomic manifestation in cluster headache (CH). Through a deductive statistics method (factor analysis) we analysed the type of autonomic symptoms reported by 157 CH patients. Three principal components were identified in the analysis: parasympathetic activation (lacrimation, conjunctival injection and rhinorrhoea), sympathetic defect (miosis and ptosis) and parasympathetic mediated effect (nasal congestion, eyelid oedema and forehead sweating). This work suggests that there are three different mechanisms underlying autonomic manifestations in CH.

Rare nocturnal headaches

PURPOSE OF REVIEW

This review describes rare headaches that can occur at night or during sleep, with a focus on cluster headaches, paroxysmal hemicrania, short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing, hypnic headache and exploding head syndrome.

RECENT FINDINGS

It is known that cluster headaches and hypnic headache are associated with rapid eye movement sleep, as illustrated by recent polysomnographic studies. Functional imaging studies have documented hypothalamic activation that is likely to be of relevance to circadian rhythms. These headache syndromes have been shown to respond to melatonin and lithium therapy, both of which have an indirect impact on the sleep-wake cycle.

SUMMARY

There is growing evidence that cluster headache and hypnic headache are chronobiological disorders.

[Dry eye disease as a complex dysregulation of the functional anatomy of the ocular surface. New concepts for understanding dry eye disease]

INTRODUCTION

Dry eye disease is a disorder of the tear film that results in epithelial damage and in a disruption of the normal homeostasis at the ocular surface. It is widespread and causes symptoms ranging from discomfort to blindness.

METHODS

A review of the existing literature was used to compare different past and recent concepts for the understanding of dry eye disease with a focus on aspects of the integrating functional anatomy of the ocular surface.

RESULTS

The understanding of the pathogenesis of dry eye disease has proceeded from the mere recognition of a lack of tears to a consideration of their quality and to the concept of wetting of the ocular surface. However, several other aspects as epithelial differentiation, innervation, hormonal status or immune protection contribute to the intact functional anatomy of the ocular surface. Recently it has been recognized that immunologically regulated mechanisms of inflammation represent a primary or secondary pathogenetic factor for dry eye disease. This is conceivably regulated by the cells of the physiological mucosal immune defence system, the eye-associated lymphoid tissue (EALT). Androgens represent an important trophic factor for the ocular surface and their deficiency predisposes to inflammation.

CONCLUSION

Dry eye disease represents a complex dysregulation of the functional anatomy of the ocular surface that can start from different alterations (e.g. insufficient secretion, defects in wetting or innervation). Immune-based inflammation is able to interconnect and negatively reinforce these different pathomechanisms, resulting in a vicious circle.

[Characteristics of hypoxia development in aged people]

The aim of the study was to investigate the peculiarities of tissue oxygen provision on the level of microcirculatory bed and to determine the significance of the indices taken separatively in pathogenesis of hypoxia in practically healthy elderly people. The study comprised 30 practically healthy people aged 60-74. It included investigation of oxygen tension in peripheral tissues, skin and bulbar microcirculation, functional state of endothelium in the group of elderly healthy people. The results obtained were compared with analogous data obtained in practically healthy young subjects. The tissue oxygen provision was found to decrease with age.

In vivo conjunctival reconstruction using modified PLGA grafts for decreased scar formation and contraction

The in vivo reconstruction of conjunctiva was investigated by using modified poly(lactide-co-glycolide) (PLGA) 50/50 scaffolds. The porous PLGA matrices were prepared by a solvent-casting particulate-leaching method with NaCl, then modified with collagen, hyaluronic acid (HA) or/and human amniotic membrane (AM) component. The growth of corneal epithelial cells and human stromal fibroblasts on the scaffolds was investigated in vitro. All the modified PLGA scaffolds demonstrated enhanced cell adhesion and proliferation as compared to PLGA untreated, and the number of cells proliferated after 1 week was increased in the order of PLGA<PLGA/collagen=PLGA/collagen/AM<PLGA/collagen/HA=PLGA/collagen/AM/HA, which was the same order as the adhesion of the cells onto the surfaces. Conjunctival wounds were created on the eyes of white rabbits bilaterally and PLGA/collagen/HA scaffolds were grafted for 4 weeks to evaluate the regeneration of ocular surface tissue at the wounds. At postoperative 4 weeks, all the wounds were completely covered with epithelial membranes. However, the contraction was minimal (6%) in the wound grafted with the modified PLGA, while that of the ungrafted wound was substantially large (25%). In addition, the collagen fibers regenerated within the scaffolds were characterized by a random array of a loose network that resembled natural conjunctiva. On the contrary, an aligned array of dense collagen fibers formed in the ungrafted wounds. Our results indicated that the modified PLGA graft as an acellular bed might allow the reconstruction of the damaged conjunctival tissue with less scar formation and contraction.

Conjunctival Healing after Amniotic Membrane Graft over Ischemic Sclera

PURPOSE

To present a case of chemical injury associated with calcification and severe conjunctival and scleral ischemia, in which tissue regeneration was achieved using an amniotic membrane graft.

METHODS

A 65-year-old man presented to our department 8 weeks after suffering a chemical injury of his left eye with sulfuric acid. There was extensive calcification of the cornea and conjunctiva, associated with severe ischemia of the adjacent sclera. After resection of the calcified tissue and nonviable tissue, amniotic membrane was grafted to cover the extensive zone of scleral ischemia.

RESULTS

In the weeks following grafting, slow epithelialization and revascularization was observed over the amniotic membrane, stemming from the surrounding healthy conjunctiva.

CONCLUSION

Although the presence of ischemia at the base of the graft has been considered a contraindication for amniotic membrane transplantation, this case demonstrates that, provided that the surrounding tissue is not affected, a graft may be useful. In such cases an amniotic membrane graft could be attempted before other alternatives, such as conjuntival or oral mucosal autografts.