In vivo confocal microscopy of the bulbar conjunctiva

Goblet cells of the normal human bulbar conjunctiva and their assessment by impression cytology sampling

Goblet cells of the conjunctiva are the main source of mucus for the ocular surface. The objectives of this review are to consider the goblet cells as assessed by various histological, cytological and electron microscopy methods, and to assess the consistency of published reports (over more than 25 years) of goblet cell density (GCD) from impression cytology specimens from nominally healthy human subjects. Reported GCD values have been notably variable, with a range from 24 to 2226 cells/mm² for average values. Data analysis suggests that a high density of goblet cells should be expected for the healthy human conjunctiva, with a tendency toward higher values in samples taken from normally covered locations (inferior and superior bulbar conjunctiva) of the open eye (at 973 +/- 789 cells/ mm²) than in samples taken from exposed (interpalpebral) locations (at 427 +/- 376 cells/mm²). No obvious change in GCD was found with respect to age, perhaps because the variability of the data did not allow detection of any age-related decline in GCD. Analyses of published data from 33 other sources indicated a trend for GCD to be lower than normal across a spectrum of ocular surface diseases.

Conjunctival findings in hyperbaric and low-tension glaucoma: an in vivo confocal microscopy study

PURPOSE

To analyse the epithelial features of the bulbar conjunctiva in hyperbaric and low-tension glaucoma (LTG) using in vivo confocal microscopy (IVCM).

METHODS

Thirty-six eyes of 36 patients [18 affected by primary open-angle glaucoma (POAG) and 18 with LTG] were studied; control group was constituted by 28 eyes of 28 healthy subjects. All eyes were examined using digital confocal laser-scanning microscopy (HRT II Rostock Cornea Module). The main IVCM outcome measurements were mean density (MMD: cysts/mm(2)) and mean total area (MMA: μm(2)) of the epithelial microcysts.

RESULTS

The mean intraocular pressure level (mmHg ± SD) was 15.1 ± 1.7, 16.3 ± 3.1 and 12.6 ± 1.8 in healthy, POAG and LTG eyes, respectively. Conjunctival microcysts were found in all patients and subjects: for healthy subjects, MMD = 10.9 ± 11.1 cysts/mm(2) and MMA = 1501.9 ± 1191.1 μm(2); for patients infected with POAG, MMD = 36.8 ± 28.6 cysts/mm(2) and MMA = 7904.8 ± 7050.5 μm(2); and for patients infected with LTG MMD = 45.6 ± 29.0 cysts/mm(2) and MMA =7946.9 ± 5227.5 μm(2). MMD and MMA were not significantly different between patients infected with POAG and those with LTG, whereas they were significantly greater in patients (fourfold and fivefold, respectively) than healthy subjects.

CONCLUSIONS

The present study demonstrated that conjunctival microcysts represent an in vivo feature in all eyes with medically controlled POAG and LTG. Therefore, conjunctiva deserves careful analysis, because its accurate microscopic definition could help clarify the pathophysiology of aqueous outflow in glaucoma.

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

PURPOSE

To investigate the age-related changes in human palpebral conjunctiva and meibomian glands by in vivo confocal microscopy.

METHODS

Forty-nine healthy volunteers (20 men and 29 women; mean age, 43.4 ± 22.7 years; range, 9-85 years) were recruited from the community. Laser scanning confocal microscopy was used to observe and measure the upper palpebral conjunctiva and meibomian glands. Customized software was used to analyze the images. The quantitative parameters included the mean densities of goblet cells, conjunctival basal epithelium, Langerhans cells, and meibomian glandular acinar units.

RESULTS

Mean densities of goblet cells, conjunctival basal epithelium, Langerhans cells, and meibomian glandular acinar units were 1050 ± 495 cells per square millimeter, 2979 ± 510 cells per square millimeter, 32 ± 16 cells per square millimeter, and 71 ± 27 glands per square millimeter in total subjects, respectively. No statistically significant difference in these 4 parameters was observed between the male and female subjects. Significant negative correlations were noted between age and goblet cell density (r = -0.646; P < 0.0001) and meibomian glandular acinar unit density (r = -0.585; P < 0.0001). However, no significant correlation was detected between the densities of conjunctival basal epithelium or Langerhans cell density and age.

CONCLUSIONS

Age-related changes under laser scanning confocal microscopy included decreased densities of goblet cells in human palpebral conjunctiva and the acinar units in meibomian glands.

The Glenn A. Fry award lecture 2010: Ophthalmic markers of diabetic neuropathy

Diabetic peripheral neuropathy (DPN) is a debilitating condition that affects about 50% of diabetic patients. The symptoms of DPN include numbness, tingling, or pain in the arms and legs. Patients with numbness may be unaware of foot trauma, which could develop into a foot ulcer. If left untreated, this may ultimately require amputation. Currently, the only method of directly examining peripheral nerves is to conduct skin punch or sural/peroneal nerve biopsies, which are uncomfortable and invasive. Indirect methods include quantitative sensory testing (assessing responses to heat, cold, and vibration) and nerve electrophysiology. Here, I describe research undertaken in my laboratory, investigating the possibility of using a range of ophthalmic markers to assess DPN. Corneal nerve structure and function can be assessed using corneal confocal microscopy and non-contact corneal esthesiometry, respectively. Retinal nerve structure and visual function can be evaluated using optical coherence tomography and perimetry, respectively. These techniques have been used to demonstrate that DPN is associated with morphological degradation of corneal nerves, reduced corneal sensitivity, retinal nerve fiber layer thinning, and peripheral visual field loss. With further validation, these ophthalmic markers could become established as rapid, painless, non-invasive, sensitive, reiterative, cost-effective, and clinically accessible means of screening for early detection, diagnosis, staging severity, and monitoring progression of DPN, as well as assessing the effectiveness of possible therapeutic interventions. Looking to the future, this research may pave the way for an expanded role for the ophthalmic professions in diabetes management.

In vivo laser scanning confocal microscopy of vernal keratoconjunctivitis

BACKGROUND

To demonstrate the morphological characteristics of vernal keratoconjunctivitis (VKC) by using in vivo laser scanning confocal microscope (LSCM).

DESIGN

Descriptive analysis of VKC by LSCM performed in EENT Hospital of Fudan University.

PARTICIPANTS

26 patients diagnosed as VKC and 26 age-matched healthy controls were enrolled in the study.

METHODS

The HRTII/RCM was used to examine bulbar conjunctiva, tarsal conjunctiva, superior limbus and inferior limbus.

MAIN OUTCOME MEASURES

The density of Langerhans cells and inflammatory cells in tarsal and bulbar conjunctiva were calculated. The morphology of Vogt Palisades was analysed and normal rate of Vogt Palisades at superior and inferior limbus was calculated, respectively.

RESULTS

Infiltration of a larger number of Langerhans cells and inflammatory cells could be identified in both bulbar conjunctiva and tarsal conjunctiva compared with normal subjects. Furthermore, the density of Langerhans cells in tarsal conjunctiva was significantly higher in tarsal form and mix form than that in bulbar form (P = 0.048). Normal Vogt Palisades were visible only in 15 and 23 eyes at superior and inferior limbus respectively. Abnormal Vogt Palisades were characterized by atrophy or absence of stromal papillae and disappearance of bright basal cells, accompanied with the infiltration of more Langerhans cells. At superior limbal area, bulbar form had the highest abnormal rate, followed by mix form, both were significantly higher than tarsal form (P = 0.005).

CONCLUSIONS

The in vivo morphological characteristics of conjunctiva and limbus in VKC included the infiltration of Langerhans cells and inflammatory cells in epithelium and stroma, and the destruction of Vogt Palisades.