Tear film and ocular surface changes after closure of the meibomian gland orifices in the rabbit

To determine whether meibomian gland dysfunction can increase tear film osmolarity and produce ocular surface changes analogous to those seen with lacrimal gland disease (keratoconjunctivitis sicca [KCS]), the authors closed the meibomian gland orifices in the right eyes of 11 rabbits by light cautery and studied the changes for 20 weeks. Tear film osmolarity was increased throughout the observation period. Conjunctival goblet cell density and corneal epithelial glycogen levels declined progressively. Closure of the meibomian gland orifices thus increased tear film osmolarity in the presence of normal lacrimal gland function and caused ocular surface abnormalities similar to KCS.     

Lacrimal gland, cornea, and tear film in the NZB/NZW F1 hybrid mouse

The NZB/NZW F1 hybrid mouse has been reported to contract a disease similar to Sj?gren's syndrome in man. We studied lacrimal gland morphology, corneal morphology, and tear osmolarity in this mouse as a function of age. Lacrimal glands of hybrid mice contained abnormal periductal infiltrates of lymphocytes and plasma cells. Maximum infiltration of the lacrimal gland occurred in the 29-week-old female hybrid mouse and was estimated to involve 12% of the gland, but was insufficient to alter tear osmolarity relative to DBA and Balb/c control mice. Nevertheless, both NZB/NZW F1 hybrid mice and DBA and Balb/c control mice had tear osmolarity and corneal surface morphology similar to that reported for keratoconjunctivitis sicca in man. Although the NZB/NZW F1 hybrid mouse may provide a valuable model for the study of lacrimal gland infiltration, since its tear osmolarity and ocular surface remain normal for a mouse, its usefulness as a model for ocular surface disease in human keratoconjunctivitis sicca may be more limited than previously thought.     

Ophthalmic solutions, the ocular surface, and a unique therapeutic artificial tear formulation

In rabbit studies, we found that extended exposure of the ocular surface to existing ophthalmic solutions resulted in gross surface abnormalities and decreases in conjunctival goblet cell density. We developed an electrolyte solution (solution 15) that preserves normal gross appearance, goblet cell density, corneal epithelial glycogen levels, and ocular surface morphologic characteristics after extended exposure to the rabbit ocular surface. We created an artificial tear formulation by adding a demulcent and a buffering system to solution 15 and reducing its osmolarity to 162 mOsm/l. We then compared our artificial tear formulation to Hypotears in a double-masked, crossover study involving 11 patients with dry-eye disorders. Our artificial tear formulation was more effective than Hypotears in decreasing tear film osmolarity and rose bengal staining, and was preferred subjectively by an eight-to-one margin.     

An electrolyte-based solution that increases corneal glycogen and conjunctival goblet-cell density in a rabbit model for keratoconjunctivitis sicca.

Thirty-two rabbits with monocular surgically induced keratoconjunctivitis sicca (KCS) underwent masked treatment for 12 weeks with 1 of 4 artificial tear solutions. Disease in each group of treated rabbits was compared with disease in untreated KCS controls. One of the solutions tested was a unique electrolyte-based formulation shown previously to preserve normal goblet-cell density after extended exposure in normal rabbits. Only the electrolyte-based solution decreased elevated tear osmolarity and sodium after 9 weeks of treatment (P less than 0.05). At 20 weeks, mean corneal glycogen and conjunctival goblet-cell density in eyes treated with the electrolyte-based solution increased significantly relative to untreated KCS controls (P less than 0.01). With the other three solutions, mean glycogen levels and goblet-cell densities were either decreased relative to untreated KCS controls (P less than 0.05) or were unchanged. The electrolyte-based solution is the first treatment to increase corneal glycogen and conjunctival goblet cells in a rabbit model of KCS.     

Ocular side effects possibly associated with isotretinoin usage

PURPOSE: To evaluate reported ocular side effects associated with isotretinoin usage. METHODS: One thousand seven hundred forty-one case reports received from spontaneous reporting systems, data from the Drug Safety Section of Roche Pharmaceuticals, and the world's literature were evaluated using the World Health Organization Causality Assessment Guide of Suspected Adverse Reactions. RESULTS: Thirty-eight different signs or symptoms of ocular abnormalities associated with isotretinoin usage have been classified as "certain," "probable/likely," "possible," "unlikely," or "conditional/unclassifiable." CONCLUSION: Adverse ocular side effects secondary to isotretinoin that are "certain" include abnormal meibomian gland secretion, blepharoconjunctivitis, corneal opacities, decreased dark adaptation, decreased tolerance to contact lens, decreased vision, increased tear osmolarity, keratitis, meibomian gland atrophy, myopia, ocular discomfort, ocular sicca, photophobia, and teratogenic ocular abnormalities. Those that are "probable/likely" are decreased color vision (reversible) and permanent loss of dark adaptation. Those that have a "possible" association include permanent keratoconjunctivitis sicca. Suggested guidelines for ocular examination for patients on isotretinoin are given.     

Tear film osmolarity and ocular surface disease in two rabbit models for keratoconjunctivitis sicca

We report the natural history of keratoconjunctivitis sicca (KCS) in two rabbit models. The first one (full KCS model) was created by closing the lacrimal gland excretory duct, and removing the nictitating membrane and harderian gland. We created the second one (lacrimal gland duct only [LGDO]-KCS model) by closing the lacrimal gland excretory duct. Although tear film osmolarity was abnormally high in both models, it was higher in the full KCS model. Decreases in corneal epithelial glycogen and in conjunctival goblet cell density, and morphological abnormalities of the conjunctiva correlated with increases in tear film osmolarity and duration of disease.     

Apoptosis of ocular surface cells in experimentally induced dry eye

PURPOSE: To evaluate to effect of experimental dry eye on ocular surface apoptosis. METHODS: Aqueous tear production and clearance were inhibited by systemic administration of scopolamine and exposure to an air draft for 12 days in 4- to 6-week-old 129SvEv/CD-1 mixed white mice. Eyes and ocular adnexa were excised, cryosectioned, and evaluated for apoptosis by terminal deoxynucleotidyl transferase-mediated dUTP-digoxigenin nick end labeling (TUNEL) assay, immunohistochemical assay for caspase-3 and poly(ADP-ribose) phosphate (PARP), and examination of nuclear morphologic changes by Hoechst DNA nuclear staining and transmission electron microscopy. RESULTS: The number of TUNEL-positive cells in the mice with induced dry eye was significantly increased compared with control mice in the following ocular regions: central corneal (P < 0.0014), peripheral corneal (P < 0.0001), bulbar conjunctival (P < 0.0021), and tarsal conjunctival (P < 0.0046) epithelia; tarsal conjunctival stroma (P < 0.0274); and lid margin (P < 0.0219, n = 4 in all cases). There were no significant differences observed between treated and control groups in the central corneal, peripheral corneal, or bulbar conjunctival stroma; meibomian glands; skin; retina-choroid; or episcleral regions. Immunohistochemistry for caspase-3 and poly(ADP-ribose) polymerase p85 fragment revealed increased immunoreactivity in regions of increased TUNEL positivity, particularly in the corneal and conjunctival epithelial cells. Ultrastructural morphologic changes consistent with apoptosis were observed in the conjunctival epithelial cells. CONCLUSIONS: Experimentally induced dry eye in mice causes apoptosis of cells in ocular surface tissues including the central and peripheral corneal epithelium, bulbar and tarsal conjunctival epithelia, tarsal conjunctival stroma, and lid margin. Apoptosis may play a key role in the pathogenesis of keratoconjunctivitis sicca and may be a therapeutic target for this condition.     

Autologous serum eye drops for the treatment of dry eye diseases

Conventional treatment of dry eye mainly consists of the use of preservative-free artificial eye drops and punctal occlusion. None of the commercially available artificial tear preparations include essential tear components such as epidermal growth factor, hepatocyte growth factor, fibronectin, neurotrophic growth factor, and vitamin A-all of which have been shown to play important roles in the maintenance of a healthy ocular surface epithelial milieu. We reported previously that autologous serum (AS) eye drops contain these essential factors and that AS eye drops are beneficial in the treatment of ocular surface diseases such as persistent epithelial defects, superior limbic keratoconjunctivitis, keratoconjunctivitis sicca, and neurotrophic keratopathy. However, there is some controversy regarding the efficacy of AS treatment. We demonstrated that this modality is more effective than artificial tears in a randomized control study. In in vivo and in vitro experiments, AS eye drops showed marked suppression of apoptosis in the conjunctival and corneal epithelium. Albumin, the major protein in serum, improved ocular surface damage in vivo and rescued apoptosis after serum deprivation in vitro. The biological background of AS eye drops and previous clinical studies of these medications for the treatment of dry eye are discussed.     

TFOS DEWS II pathophysiology report

The TFOS DEWS II Pathophysiology Subcommittee reviewed the mechanisms involved in the initiation and perpetuation of dry eye disease. Its central mechanism is evaporative water loss leading to hyperosmolar tissue damage. Research in human disease and in animal models has shown that this, either directly or by inducing inflammation, causes a loss of both epithelial and goblet cells. The consequent decrease in surface wettability leads to early tear film breakup and amplifies hyperosmolarity via a Vicious Circle. Pain in dry eye is caused by tear hyperosmolarity, loss of lubrication, inflammatory mediators and neurosensory factors, while visual symptoms arise from tear and ocular surface irregularity. Increased friction targets damage to the lids and ocular surface, resulting in characteristic punctate epithelial keratitis, superior limbic keratoconjunctivitis, filamentary keratitis, lid parallel conjunctival folds, and lid wiper epitheliopathy. Hybrid dry eye disease, with features of both aqueous deficiency and increased evaporation, is common and efforts should be made to determine the relative contribution of each form to the total picture. To this end, practical methods are needed to measure tear evaporation in the clinic, and similarly, methods are needed to measure osmolarity at the tissue level across the ocular surface, to better determine the severity of dry eye. Areas for future research include the role of genetic mechanisms in non-Sjögren syndrome dry eye, the targeting of the terminal duct in meibomian gland disease and the influence of gaze dynamics and the closed eye state on tear stability and ocular surface inflammation.     

Morphologic Effect of Hyperosmolarity on Rabbit Corneal Epithelium

The morphologic effect of hyperosmolarity, equivalent to that seen in the tear film of patients with keratoconjunctivitis sicca (KCS), on rabbit corneal epithelium in vitro and in vivo was studied. In the in vitro studies, corneal epithelium was grown in explant cultures. Control tissue was cultured in a 307 mOsm/L medium. Epithelium cultured in the 333, 361 and 363 mOsm/L media showed decreased intercellular connections, blunting and loss of microplicae, disruptions in cell membranes and cellular swelling with decreased cytoplasmic density. In in vivo studies, corneas bathed in balanced salt solutions (BSS) concentrated to 330, 360, or 407 mOsm/L showed increased cell desquamation, and the cell changes observed at similiar osmolarities in the in vitro studies. The tear film osmolarities observed in KCS are sufficient to cause the corneal epithelial changes seen in patients with this disease.     

Quantitative evaluation of the early changes in ocular surface inflammation following MMC-aided papillary resection in severe allergic patients with corneal complications

BACKGROUND: Atopic keratoconjunctivitis (AKC) and vernal keratoconjunctivitis (VKC) are chronic inflammatory allergic diseases that are associated with some common conjunctival and corneal complications.1 The clinical corneal manifestations of both entities may include superficial punctate keratitis, macroerosions, corneal ulceration, plaque formation, corneal neovascularization, and lipid infiltration. PURPOSE: To quantitatively evaluate the early ocular surface inflammation before and after mitomycin C (MMC)-aided papillary resection in severe allergy patients with corneal complications. METHODS: Three eyes with VKC and 5 eyes with AKC were included in this study. All eyes had cobblestone-like papillae on the upper tarsal conjunctiva and corneal complications such as corneal ulcers, defect, or erosions that were refractory to conventional treatment of more than 2 weeks. Papillary resection with intraoperative 0.05% MMC application for 5 minutes on the palpebral conjunctiva was carried out in all eyes. Corneal and conjunctival findings were evaluated before and 1 week and 2 weeks after surgery. Brush cytology (BC) and evaluation of tear eosinophilic cationic protein (ECP) levels by radioimmunoassay techniques were performed as well pre- and postoperatively. RESULTS: Corneal and conjunctival complications resolved in all patients within 7 days after resection. Postoperative tear ECP levels decreased significantly with papillary resection (P< 0.05). Concomitant brush cytology showed a significant decrease in the number of eosinophils and neutrophils following papillary resection (P < 0.05). CONCLUSION: MMC-aided papillary resection provided a dramatic decrease in ocular surface inflammation as evidenced by decrease in the number of inflammatory cells as well as tear ECP levels with a rapid improvement of clinical corneal and conjunctival findings.     

Toxic ulcerative keratopathy. An unrecognized problem

The authors describe 19 patients with toxic ulcerative keratopathy. These patients were referred with other diagnoses and were victims of overtreatment. Fourteen of these patients had iatrogenic toxic keratopathy, and the other five had self-induced keratoconjunctivitis. The corneal defects tended to be inferior or inferonasal and associated with an intense, coarse superficial keratitis in "comet's impact" fashion. Conjunctival hyperemia, chemosis, and conjunctival staining were considerably more prominent inferiorly and inferonasally. Diagnosis was the key element in management. Treatment consisted of discontinuation of the offending medication or preservative. Other important measures included preservative-free medications, patching, therapeutic contact lenses, goggles, and viscoelastic agents. Many of the patients with iatrogenically induced toxic keratopathy had significant ocular surface disease such as keratoconjunctivitis sicca (6 patients), previous intraocular surgery (6 patients), herpes simplex infection (1 patient), or herpes zoster infection (1 patient).     

Open-label crossover study of vitamin A ointment as a treatment for keratoconjunctivitis sicca

The authors evaluated the efficacy of all-trans retinoic acid (vitamin A) ointment as a treatment for keratoconjunctivitis sicca (KCS) in a group of 11 patients selected on the basis of clinical history, slit-lamp examination results, rose Bengal staining, and tear film osmolarity. In this open-label crossover study, vitamin A ointment was no more effective than placebo in increasing tear secretion, as indicated by Schirmer test with proparacaine or tear film osmolarity, or in decreasing ocular surface disease, as indicated by rose Bengal staining. Seven patients stated some preference for the placebo ointment, two patients for the vitamin A ointment, and two patients had no preference.     

Alteration of the ocular surface with recurrence of granular/avellino corneal dystrophy after phototherapeutic keratectomy: report of five cases and literature review

PURPOSE: To study the changes in ocular surface findings with recurrence after phototherapeutic keratectomy (PTK) in patients with Avellino and granular dystrophy. DESIGN: Observational case series. PARTICIPANTS: Five eyes of five patients with recurrent granular/Avellino corneal dystrophy after PTK seen at Kobe Kaisei Hospital were studied. INTERVENTION: The patients underwent routine ophthalmic examinations, corneal sensitivity measurements, tear film breakup time (BUT), Schirmer test, tear film lipid layer interferometry, and conjunctival impression cytology. MAIN OUTCOME MEASURES: The alterations of clinical features, tear function, and conjunctival impression cytology parameters with a recurrence after PTK were investigated. RESULTS: The average pre-PTK corneal sensitivity and tear film breakup time were low in all five patients. Tear film lipid layer interferometry grade and conjunctival squamous metaplasia displayed higher grades before PTK. All of these parameters improved gradually after PTK and were maintained until a recurrence, which was associated with further worsening of the corneal sensitivity, tear function, and impression cytology parameters. CONCLUSIONS: Although PTK improves the ocular surface health in granular/Avellino corneal dystrophies, recurrence of the initial dystrophy is associated with decline of the ocular surface health parameters. Our findings also suggest that corneal epithelium is most probably involved in the recurrence of the disease process in Avellino/granular corneal dystrophy.     

Ocular surface and MUC5AC alterations in atopic patients with corneal shield ulcers

PURPOSE: To describe MUC5AC alterations and the ocular surface disorder in atopic patients with or without corneal ulcers. METHODS: Atopic patients' eyes were divided into two groups according to the presence and absence of corneal ulceration. The subjects underwent corneal sensitivity measurements, Schirmer test, tear film break-up time (BUT), fluorescein and Rose Bengal staining of the ocular surface and conjunctival impression cytology and brush cytology. Impression cytology samples underwent PAS and immunohistochemical staining for MUC5AC. Brush cytology specimens underwent evaluation for inflammatory cell expression and quantitative real-time PCR for MUC5AC mRNA expression. The differences related to the tear function and ocular surface examination parameters between patients with and without corneal ulceration and healthy control subjects were studied. In addition, the differences of the study parameters related to ocular surface epithelial health and inflammatory status between patient eyes with atopic keratoconjunctivitis (AKC) and vernal keratoconjunctivitis (VKC) were investigated. RESULTS: The mean corneal sensitivity and BUT values were significantly lower in atopic patients with corneal ulcers, compared to patients without ulcers and controls (p < 0.001). Brush cytology specimens from patients with corneal ulcers revealed significantly higher expression of inflammatory cells compared to patients without ulcers and controls (p < 0.001). Impression cytology samples from eyes with corneal ulcers showed significant squamous metaplasia and reduction in goblet cell density compared to eyes without ulcers and eyes of control subjects. The mean squamous metaplasia grade was significantly higher in eyes with AKC compared to eyes with VKC (p < 0.02). The mean goblet cell density was significantly lower in eyes with AKC compared to eyes with VKC (p < 0.01). Specimens from eyes with corneal ulcers showed PAS positive mucin pickup and did not stain positive for MUC5AC. MUC5AC mRNA expression was significantly lower in eyes with corneal ulcers compared to eyes without ulcers and eyes of control subjects. MUC5AC mRNA expression was also significantly lower in eyes with AKC compared to eyes with VKC. CONCLUSIONS: Ocular surface inflammation, tear film instability, and decreased conjunctival MUC5AC mRNA expression were thought to be important in the pathogenesis of noninfectious corneal shield ulcers in atopic ocular surface disease.     

Ocular surface drying and tear film osmolarity in thyroid eye disease

Five factors potentially associated with corneal exposure--palpebral fissure width, exophthalmos, blink rate, lagophthalmos, and lid lag--were evaluated in 17 patients with Graves' disease to determine which were associated with ocular surface damage. Multiple regression analysis revealed that increased palpebral fissure width and increased blink rate were both significant predictors of ocular surface damage (as measured by rose Bengal staining). Tear osmolarity and tear film break-up time were measured to determine the type of drying mechanism involved in thyroid eye disease. All eyes examined except one had blink rates adequate to prevent dry-spot formation. Fourteen of 33 eyes had abnormally high tear osmolarity. Increasing palpebral fissure width and increasing blink rate were both significant predictors of elevated osmolarity in tears obtained from the inferior marginal tear strip. We suspect that increased palpebral fissure width accelerates tear film evaporation, thus increasing tear film osmolarity with resultant ocular surface damage.     

Management of filamentary keratitis associated with aqueous-deficient dry eye.

PURPOSE: To review the incidence, underlying pathophysiology, and clinical features of filamentary keratitis and to identify evidence-based best-practice strategies for managing filamentary keratitis. METHODS: A comprehensive review of published literature was undertaken. Recommendations for best-practice management strategies were based on the available evidence. Three cases are presented to illustrate the clinical findings and management of patients with chronic filamentary keratitis. RESULTS: Although the evidence base is limited by the absence of well-designed studies, current evidence indicates the following: (1) Aqueous-deficient dry eye (keratoconjunctivitis sicca) is the most common ocular condition associated with filamentary keratitis. (2) Current best-practice management of filamentary keratitis involves treating the underlying dry eye and specific treatments for the corneal filaments. Proposed treatments include nonpreserved lubricants, topical steroidal and nonsteroidal anti-inflammatory agents, and punctal plugs for aqueous-deficient dry eye as well as mechanical removal of filaments, hypertonic saline, mucolytic agents, and bandage contact lenses for the filaments. (3) Filamentary keratitis can be induced or exacerbated by contact lens wear and ocular surgical procedures such as cataract surgery and corneal graft surgery. Pre- and postoperative ocular surface management strategies should be considered in the surgical planning of patients with, or who are susceptible to, filamentary keratitis. Filamentary keratitis can also be induced and/or exacerbated by chronic use of ocular and/or systemic medications, and alternate medications or additional measures to manage the tear film and ocular surface may be required in these cases. CONCLUSIONS: Filamentary keratitis can be a chronic, recurrent, and debilitating condition. With a systemic approach to diagnosis and management, the condition can be effectively controlled and the incidence and severity of recurrences minimized.     

Corneal contact time of artificial tear solutions

In 30 subjects without ophthalmological disease the corneal contact time of a new artificial polyacrylic-based tear gel (Vidisic, produced by Dr. Mann, Berlin) was compared with a well-known artificial polyvinyl alcohol-based tear solution. The Vidisic concentration remained in the corneal tear film 7 times longer than the substance it was compared with. In a second study including 7 normal subjects and 5 patients with keratoconjunctivitis sicca, the influence of Vidisic on break-up time (BUT) and the Schirmer test was demonstrated. It was found that tear secretion improved for 2-4 hours (Schirmer test) and the stability of the tear film (BUT) improved for about 6 hours with Vidisic. These results suggest that application of Vidisic four times a day is sufficient for efficatious therapy even in cases of severe keratoconjunctivitis sicca.     

春季角结膜炎活动期眼表和泪液蛋白的临床研究

目的　对比观察春季角结膜炎（ｖｅｒｎａｌｋｅｒａｔｏｃｏｎｊｕｎｃｔｉｖｉｔｉｓ,ＶＫＣ）活动期患者眼表症状、泪膜、泪液蛋白以及角膜神经改变的特点。方法　收集南昌大学第一附属医院２０１０年８月至２０１４年３月眼科门诊确诊为ＶＫＣ活动期患者２０例（４０眼）,分别对患者行眼表症状评分、泪膜四项检查、泪液蛋白测定、角膜知觉检查与中央角膜共聚焦显微镜检查,并与２０例４０眼健康对照组研究对象的检查结果进行对比分析。结果　ＶＫＣ活动期患者左右两眼间和正常对照组研究对象的左右两眼间的眼表症状评分、泪膜四项、泪液蛋白、乳铁蛋白、溶菌酶、神经纤维密度及角膜敏感度差异均无统计学意义（均为Ｐ＞０．０５）;ＶＫＣ活动期患者右眼较对照组右眼干眼症状眼数增多,眼表疾病指数评分增高、泪膜破裂时间减短、基础泪液分泌试验结果增高、泪河高度降低、角膜荧光素染色增强,泪液总蛋白、乳铁蛋白、溶菌酶、角膜神经纤维密度及角膜敏感度值较对照组均明显降低,且差异均有统计学意义（均为Ｐ＜０．０５）;ＶＫＣ活动期患者左眼检查结果较对照组改变与右眼改变一致,差异也均有统计学意义（均为Ｐ＜０．０５）。共聚焦显微镜检查结果发现,ＶＫＣ活动期患者中央角膜可见角膜上皮细胞部分结膜化,其上皮层存在大量炎症细胞浸润并伴有少量朗格汉斯细胞浸润,角膜上皮下有大量非成熟型朗格汉斯细胞浸润;角膜上皮下神经纤维纤细,呈盘旋、弯曲异常分布。结论　ＶＫＣ活动期患者眼表及泪液改变明显,多表现为泪膜稳定性降低,泪液蛋白含量降低,角膜敏感度降低且角膜神经纤维密度下降、纤细及走形异常等特点。