Density and distribution of dendritiform cells in the peripheral cornea of healthy subjects using in vivo confocal microscopy.

PURPOSE: To establish in a large healthy cohort, dendritiform cell (DC) density and morphological parameters in the central and peripheral cornea using in vivo confocal microscopy (IVCM). METHODS: A prospective, cross-sectional, observational study was conducted in 85 healthy volunteers (n = 85 eyes). IVCM images of corneal center and four peripheral zones were analyzed for DC density and morphology to compare means and assess correlations (p < 0.05 being statistically significant). RESULTS: Central corneas had lower DC density (40.83 ± 5.14 cells/mm2; mean ± SEM) as compared to peripheral corneas (75.42 ± 2.67 cells/mm2, p < 0.0001). Inferior and superior zones demonstrated higher DC density (105.01 ± 7.12 and 90.62 ± 4.62 cells/mm2) compared to the nasal and temporal zones (59.93 ± 3.42 and 51.77 ± 2.98 cells/mm2, p < 0.0001). Similarly, lower DC size, field and number of dendrites were observed in the central as compared to the average peripheral cornea (p < 0.0001), with highest values in the inferior zone (p < 0.001 for all, except p < 0.05 for number of dendrites in superior zone). DC parameters did not correlate with age or gender. Inter-observer reliability was 0.987 for DC density and 0.771-0.922 for morphology. CONCLUSION: In healthy individuals, the peripheral cornea demonstrates higher DC density and larger morphology compared to the center, with highest values in the inferior zone. We provide the largest normative cohort for sub-stratified DC density and morphology, which can be used in future clinical trials to compare differential changes in diseased states. Furthermore, as DC parameters in the peripheral zones are dissimilar, random sampling of peripheral cornea may be inaccurate.

Scleral Contact Lenses in an Academic Oculoplastics Clinic: Epidemiology and Emerging Considerations.

PURPOSE: To describe the role and efficacy of scleral contact lenses (SCLs) in the treatment of progressive keratopathy in patients who have undergone periocular surgical procedures, to investigate the financial impact of these surgical interventions, and to demonstrate the role of oculoplastic surgery in improving scleral contact lens fit. METHODS: A retrospective medical record review was performed to identify patients who both received SCLs and were examined by the oculoplastics service at the University of Iowa between January 1990 and December 2015. Inclusion criteria also required a minimum of 12 months of patient follow up after being fit with a SCL. The indication for SCL use, as well as clinical outcomes and cumulative relative value units (RVUs) of prior oculoplastic treatments and SCL therapy were recorded for each patient. RESULTS: Six hundred and fifty-nine patients were fitted with SCLs at the authors' institution during the 25-year study period, 43 of whom were examined by the oculoplastics service for reasons related to their SCL. Patients who were fitted for SCLs before (27 patients) or after (16 patients) evaluation in the oculoplastics clinic presented with a variety of corneal and periocular pathology. Corneal indications for SCLs in patients seen secondarily in the oculoplastics clinic included decreased corneal sensation (from CN V palsy or neurotrophic keratopathy), decreased corneal healing from limbal stem cell deficiency, exposure keratopathy, and keratoconjunctivitis sicca secondary to Sjogren's syndrome or orbital radiation. Indications for oculoplastic clinic evaluation in current scleral lens patients included lagophthalmos, trichiasis, epiphora, cicatricial changes in the eyelids or fornices, and eyelid or eyebrow malposition affecting SCL centration. In all 27 patients, surgical intervention resulted in improved SCL centration. Sixteen patients (5 with CN VII palsy, 4 with CN V and CN VII palsy, 4 with neurotrophic keratitis, and 3 with cicatricial entropion) had progressive corneal decompensation despite primary oculoplastics procedures to protect the cornea and ultimately benefitted from SCL treatment secondarily. Fourteen of these 16 patients demonstrated an improved visual acuity of 1 line or more using SCLs. Procedures performed before referral for SCLs included tarsorrhaphies, gold weights, ectropion repair with lateral tarsal strip, retraction repair with spacer grafts, full-thickness skin grafts, cheek lifts, and punctal occlusion. The total RVUs of these procedures performed per patient were tabulated. The RVU range was 10.47-33.96 with an average of 19.5 RVUs (standard deviation = 9.4 RVUs) per patient. CONCLUSIONS: Scleral contact lenses may offer a useful alternative to stabilize the ocular surface, improve vision, and minimize the financial impact and morbidity of multiple periocular procedures in select patients with progressive keratopathy of varying etiologies. The therapeutic indications and utilization of SCLs are likely to increase in oculoplastic practices with optometric support, particularly in academic settings. Surgical correction of eyelid and eyebrow malposition, as well as epiphora, may also be useful adjunctive procedures to optimize SCL fit.

Efficacy of an artificial tear emulsion in patients with dry eye associated with meibomian gland dysfunction.

OBJECTIVES: The aim of the study reported here was to assess the efficacy of an artificial tear emulsion for the treatment of dry eye associated with meibomian gland dysfunction (MGD). METHODS: At five clinics, patients completed a 1-week treatment with their habitual topical therapy and then a 4-week treatment with open-label study medication: Systane® Balance Lubricant Eye Drops (Alcon, Alcon Inc, Fort Worth, TX, USA). Subjective assessments included a preference survey, the Impact of Dry Eye in Everyday Life questionnaire, and the Work Productivity and Activity Impairment questionnaire. Objective assessments by unmasked investigators included visual acuity, meibomian gland expression and dropout, tear film breakup time, corneal staining, and dosing frequency. RESULTS: At baseline, the 49 patients had mean meibomian gland expression grades and gland dropout that indicated mild to moderate MGD. Patients administered their habitual therapy 2.5 ± 1.3 times per day. After 4 weeks of study medication, the Impact of Dry Eye in Everyday Life questionnaire results indicated statistically and clinically significant improvements. Fewer than half of the participants were employed, limiting the usefulness of the Work Productivity and Activity Impairment questionnaire. Visual acuity remained statistically similar, while corneal staining and tear film breakup time improved significantly (P < 0.05) but modestly. The outcomes were achieved with 1.9 ± 1.1 doses per day of study medication, a significantly lower frequency than the habitual frequency (P < 0.001). The most common medication-related adverse event was blurred vision (3/49 patients, 6.1%). At study conclusion, 27/44 (61.4%) survey respondents preferred the study medication to their habitual therapy. CONCLUSION: The artificial tear emulsion was effective for treating the signs and symptoms of dry eye in MGD patients.

Rapid image evaluation system for corneal in vivo confocal microscopy.

PURPOSE: To develop rapid image processing techniques for the objective analysis of corneal in vivo confocal micrographs. METHODS: Perpendicular central corneal volume scans from healthy volunteers were obtained via laser in vivo confocal microscopy. The layer in each volume scan that contained the nerve plexus was detected by applying software operators to analyze image features on the basis of their size, shape, and contrast. Dendritic immune cells were detected in the nerve image on the basis of cellular size, lack of elongation, and brightness relative to the nerves. Images that were 20 µm anterior to the best nerve layer images were used for the analysis of epithelial wing cells; wing cell detection was based on extended regional minima and a watershed transformation. RESULTS: The software successfully detected the best nerve layer images in 15 scans from 15 eyes. Manual and automatic analyses were 81.8% in agreement for dendritic immune cells (for 11 cells in a representative image) and 94.4% in agreement for wing cells (for 466 cells in the image). Within 10 seconds per scan, the software calculated the number, mean length, and mean density of immune cells; the number, mean size, and mean density of wing cells; and the number and mean length of nerves. Factors defining the shape and position of cells and nerves also were available. CONCLUSIONS: The software rapidly and accurately analyzed the in vivo confocal micrographs of the healthy central corneas, yielding quantitative results to describe the nerves, dendritic immune cells, and wing cells.

Dendritic immune cell densities in the central cornea associated with soft contact lens types and lens care solution types: a pilot study.

BACKGROUND: The purpose of this study was to assess whether differences in central corneal dendritic immune cell densities associated with combinations of soft contact lenses and lens care solutions could be detected by in vivo confocal microscopy. METHODS: Participants were adults naïve to contact lens wear (n = 10) or who wore soft contact lenses habitually on a daily-wear schedule (n = 38) or on a study-assigned schedule for 30 days with daily disposable silicone hydrogel lenses (n = 15). Central corneas were scanned using an in vivo confocal microscope. Cell densities were compared among groups by demographic parameters, lens materials, and lens care solutions (polyhexamethylene biguanide [PHMB], polyquaternium-1 and myristamidopropyl dimethylamine [PQ/MAPD], peroxide, or blister pack solution [for daily disposable lenses]). RESULTS: Among lens wearers, no associations were observed between immune cell densities and age, gender, or years of lens-wearing experience. Mean cell density was significantly lower (P < 0.01) in nonwearers (29 ± 23 cells/mm(2), n = 10) than in lens wearers (64 ± 71 cells/mm(2), n = 53). Mean cell density was lower (P = 0.21) with traditional polymer lenses (47 ± 44 cells/mm(2), n = 12) than with silicone hydrogel lenses (69 ± 77 cells/mm(2), n = 41). Lowest to highest mean density of immune cells among lens wearers was as follows: PQ/MAPD solution (49 ± 28 cells/mm(2)), blister pack solution (63 ± 81 cells/mm(2)), PHMB solution (66 ± 44 cells/mm(2)), and peroxide solution (85 ± 112 cells/mm(2)). CONCLUSION: In this pilot study, in vivo confocal microscopy was useful for detecting an elevated immune response associated with soft contact lenses, and for identifying lens-related and solution-related immune responses that merit further research.

Effects of fluorescein staining on laser in vivo confocal microscopy images of the cornea.

This study was designed to identify whether topical fluorescein, a common ophthalmic tool, affects laser in vivo confocal microscopy of the cornea, a tool with growing applications. Twenty-five eye care specialists were asked to identify presence or absence of fluorescein in 99 confocal micrographs of healthy corneas. Responses were statistically similar to guessing for the epithelium (48% ± 14% of respondents correct per image) and the subbasal nerve plexus (49% ± 11% correct), but results were less clear for the stroma. Dendritic immune cells were quantified in bilateral images from subjects who had been unilaterally stained with fluorescein. Density of dendritic immune cells was statistically similar between the unstained and contralateral stained eyes of 24 contact lens wearers (P = .72) and of 10 nonwearers (P = .53). Overall, the results indicated that fluorescein staining did not interfere with laser confocal microscopy of corneal epithelium, subbasal nerves, or dendritic immune cells.

Contact lens strategies for the patient with dry eye.

Dry eye is the most common reason for contact lens (CL) discontinuation, and the patient with pre-existing dry eye presents particular challenges to the CL fitter. Poor tear film quality/stability, oxygen deprivation, lens deposits, and adverse reactions to CL solutions all contribute to dry eye, and lid disease, allergies, environmental factors, and medications can further hamper successful CL wear by the patient with dry eye. Health and comfort of the ocular surface is affected by the water content, ionicity, oxygen permeability, and modulus of elasticity of the lens, as well as by surface characteristics, such as protein, lipid, and mucin deposition; protein adsorption; and wettability. The choice of CL cleaning solutions with regard to action, cytotoxicity, and biocompatibility are as important as the choice of the CL itself. With appropriate management of the lid, meibomian gland, and ocular surface conditions that produce dry eye, careful selection of lenses and solutions, and vigilant follow-up, successful CL wear should be achievable for the dry eye patient.