Bulbar Conjunctival Surface Research Articles

Eversion of the Third Eyelid Cartilage in a Cat

Background: Eversion of the cartilage of the third eyelid is a rare congenital disease in cats. It is caused by the anterior eversion of the cartilage edge of the third eyelid. Clinical signs may be associated with secondary keratoconjunctivitis, third eyelid gland protrusion, and ocular surface irritation. The diagnosis is made by ophthalmic examination, and treatment consists of surgical resection of the everted cartilage portion. The goal of the present study was to report a case of eversion of third eyelid cartilage in a cat, given that it is an unusual abnormality in this animal species, and an important differential diagnosis to be considered in the disorders of the third eyelid.Case: A 6-year-old neutered female Persian cat was presented with a presumptive diagnosis of protrusion of the third eyelid gland, history of ocular irritation, and epiphora in the left eye. The disorder had been intermittently present since the animal was 1-year-old, with spontaneous disappearance after approximately 15 days. The owner related the reappearance of the disorder to stressful situations, with no previous history of trauma or other ocular alteration. During the ophthalmic examination, suspended solute was observed through biomiscroscopic examination in both eyes, as well as an increase in volume of the third eyelid in the left eye, without other changes. A thorough examination, under general anesthesia, indicated the protruding volume of the cartilage of the everted third eyelid. The third eyelid was pleated in its upper portion, demonstrating that the cartilage of the third eyelid was folded instead of following the curvature of the ocular surface. Under general anesthesia, the cartilage was partially removed through two parallel incisions on the bulbar conjunctival surface, divulsioning 5 mm in length in the vertical portion of the cartilage in a ‘T’ shape, and separating the conjunctiva from the underlying cartilage. The everted portion of cartilage, once removed, was in fact considered curved in its most dorsal portion, in a manner similar to what was reported in dogs. The third eyelid returned to its anatomically correct position after removing the deformed portion of the cartilage. The patient was treated postoperatively with topical drops of tobramycin and dexamethasone 3 mg/mL + 1 mg/mL (Tobradex®), and lubricant based on sodium hyaluronate 2 mg/mL (Hylo®-Gel). No complications were observed in the postoperative consultations during a 8 month follow-up.Discussion: It is suspected that the eversion of the third eyelid cartilage occurs due to a differential growth rate between the posterior and anterior portions of the cartilage; even though other theories have been proposed. The cartilage of the third eyelid can commonly be everted in large dog breeds, being classified as a disease of hereditary character. However, it has rarely been reported in cats, which can be explained by the more elastic histological constitution when compared to that of dogs. The surgical procedure performed in the present case of eversion of the third eyelid cartilage in a cat was in accordance with that described in the literature. Complete recovery of the third eyelid function was achieved, and the patient's ocular health was preserved. The reported case showed a favorable prognosis after diagnosis, associated with correct treatment and postoperative management. Although there was an effective recovery of the third eyelid, the issues related to the pathophysiology of cartilage eversion are unknown. This way, further studies are necessary to elucidate its etiology.

Tear film concentrations of topically applied 0.5% oxytetracycline ointment in normal canine eyes.

To determine the tear film levels of oxytetracycline in normal canine eyes after application of the ophthalmic ointment, Terramycin™ (0.5% oxytetracycline, polymyxin B sulfate), to guide appropriate treatment frequency. Ten research beagles. Ten research beagles with confirmed normal eyes were administered 0.02mL of Terramycin™ ophthalmic ointment onto the dorsal bulbar conjunctival surface of the right eye. Tear samples were collected via dye-less Schirmer tear strips at 2, 4, 6, 8, and 12hours post-administration. The sample for each timepoint was collected on a separate day, and concentrations of oxytetracycline were determined using high-performance liquid chromatography (HPLC). There was a semi-logarithmic decline in the median tear concentration of oxytetracycline. The median (2.5th and 97.5th percentiles) tear concentrations of oxytetracycline at 2, 4, 6, 8, and 12hours were 43.5μg/mL (11.1-302.2μg/mL), 28.7μg/mL (8.04-113.7μg/mL), 16.1μg/mL (4.96-37.7μg/mL), 9.2μg/mL (4.52-28.1μg/mL), and 6.11μg/mL (4.36-26.7μg/mL), respectively. Mean (±SD) drug recovery via HPLC was 88% (±7.5%). Ophthalmic Terramycin™ achieves a substantially higher tear level than the MIC for common bacterial corneal pathogens up to 12hours post-administration in normal eyes. Anti-collagenolytic tear levels were not achieved at the timepoints evaluated or with the manufacturer-prescribed dosing frequency. HPLC can be used to analyze tear concentrations of ophthalmic ointment formulations.

The conjunctival crypt of the equine third eyelid

SummaryThe purpose of this study is to characterise the gross anatomy of a relatively large, cryptic structure within the bulbar conjunctival surface of the equine third eyelid that has commonly been observed by the authors during equine ophthalmic examinations. In this study, cadaveric eyes and adnexa were obtained from 13 Quarter Horses without history of ocular disease. The gross anatomy of the bulbar surface of the third eyelid was characterised by digital macrophotography and with an image capture system using an operating microscope. A well‐defined cryptic structure was readily identified in the majority of eyes (17/26). The location of the crypt varied but was most commonly observed within the central aspect of the bulbar surface of the third eyelid, often in close proximity to prominent blood vessels oriented perpendicular to the leading edge of the third eyelid. A patch of lymphoid follicles was often observed surrounding the crypt. The rectangular shape and upward facing orientation of the crypt was akin to a shirt's breast pocket. Width and depth were variable but ranged between 1 and 8 mm in either dimension. Some crypts were complex, with multiple channels observed within the primary opening. In conclusion, this study confirms the presence of a well‐organised mucosal crypt within the bulbar surface of the equine third eyelid capable of harbouring foreign material and ocular irritants. Additional anatomical characterisation of the macro‐crypt by light microscopy, immunohistochemistry and electron microscopy is underway. Evaluation of this structure by equine practitioners and veterinary ophthalmologists should be performed during the routine ophthalmic examination to better understand its role in ocular disease.

Microbiology of corneal wounds after cataract surgery: biofilm formation and antibiotic resistance patterns.

To evaluate the bacterial flora of corneal wounds at the end of cataract surgery before intracameral antibiotic use and to determine agents to treat postoperative endophthalmitis, the potential for biofilm formation, and antibiotic resistance. This cross-sectional clinical study included patients who underwent cataract surgery using the phacoemulsification technique without any complications. The hemifacial skin, periocular area, eyelids and eyelashes were washed with 10% povidone-iodine and the conjunctiva was washed with 5% povidoneiodine before cataract surgery. After uncomplicated surgery, a wipe sample was taken from the bulbar conjunctival surface, corneal surface, and wound rim before administering intracameral antibiotics. All samples were plated on blood agar, MRS agar, M17 agar, calcium-lactate agar, plate-count agar, and Sabouraud-dextrose agar. Biofilm formation was evaluated by microtitre plates and the Congo red-agar method. Antimicrobial resistance patterns of isolates were determined by the agar-disk diffusion method. We recruited 50 patients and studied 55 eyes, obtaining 34 isolates from the cultures of 16 eyes. Isolated organisms were coagulase-negative staphylococci (CoNS) (35.3%), Bacillus cereus (29.4%) and Pseudomonas spp. (5.9%). We obtained isolates from 64% of diabetic cases and 20% of non-diabetic cases, (p=0.002). It was observed that 21 out of 34 isolates produced a weakly positive biofilm, 8 were moderately positive, three were strongly positive, and two isolates were biofilm negative. Of the CoNS strains four of the 11 were resistance to four or more antibiotics. Microorganisms that remained at the end of cataract surgery had the capacity to produce biofilm and had high antibiotic resistance. Appropriate preoperative disinfection is very important and adequate disinfection and suitable antibiotics should be kept in mind for avoiding endophthalmitis, especially for diabetic patients. Biofilm is one of the major factors affecting the virulence of bacteria, and further studies into prevention of biofilm formation are required in this area.

Assessment of Goblet Cell Orifice Distribution Across the Rabbit Bulbar Conjunctiva Based on Numerical Density and Nearest Neighbors Analysis

Purpose: To assess density and spatial distribution of the goblet cell orifices at the surface of the rabbit bulbar conjunctiva as an indicator of functional activity.Methods: Specimens of the superior or inferior bulbar conjunctiva from six healthy young adult (2 kg) pigmented rabbits were obtained using a special preparation technique by which the conjunctiva was carefully stretched out during fixation with buffered glutaraldehyde. The apical surface of the specimens was examined by scanning electron microscopy. From high magnification prints, the areas and dimensions of 32–49 orifices/image were measured. In addition, the centre-to-centre spacing and spatial distribution of the orifices were assessed using a nearest neighbors principle.Results: The bulbar conjunctival surface is composed of polygonal cells decorated with surface microplicae and in between which are individual goblet cell orifices. The goblet cell orifices are characterized by tending to be oval in shape (long:short dimensions ratio of 1.57 +/− 0.23) and usually having a distinct line of microvilli around the perimeter. The orifices had a wide range of areas (from 13 to 188 μm2; group mean +/− SD of 54 +/− 36 μm2), and distribution of orifice areas was skewed or even bimodal. The overall orifice density was 387 +/− 68/mm2, with the group-averaged nearest neighbors distance being 34 +/− 3 μm. Comparisons of the measured nearest neighbors distances to that for an optimum spacing based on numerical density reveals the goblet cell orifices to be slightly further apart and that they were not obviously in groups or clustered.Conclusions: Goblet cell orifices at the bulbar conjunctival surface, a presumed indicator of functional secretory activity, appear to have reproducible density and a discrete and reasonably predictable spatial distribution.

Thermal cautery of the canine third eyelid for treatment of cartilage eversion

To present a novel, minimally invasive technique for everted third eyelid cartilage correction in dogs that employs the use of low-energy cautery to remodel the cartilage. Twelve eyes of ten dogs had cautery performed under general anesthesia to correct everted third eyelid cartilage. The tip of a handheld cautery unit or an electrocautery handpiece was applied to the bulbar conjunctival surface of the third eyelid at the central location of cartilage convexity and treated to effect. This resulted in gradual conjunctival contraction and cartilage softening that remodeled the third eyelid to return to a more normal, physiologic position. When the tips of the cartilage bar were also curled, cautery was briefly applied to the convex surface to straighten the cartilage in a similar manner. Blanching of the conjunctiva at the site of treatment occurred. Char was sometimes present and was gently removed with a scalpel blade to improve postoperative patient comfort. Mild conjunctival hyperemia was noted in a few patients for 1-2days after surgery, but there were no signs of discomfort or eyelid swelling. All dogs had good results in terms of cartilage correction with no recurrence; however, one of the Great Danes that had concurrent third eyelid gland prolapse required gland replacement surgery. Thermal cautery is a simple, inexpensive means of correcting third eyelid cartilage eversion in dogs with a high rate of success that preserves normal tissue while restoring function.

Nucleus and cell size changes in human bulbar conjunctival cells after soft contact lens wear, as assessed by impression cytology

Purpose To specifically assess the nucleus size and its relationship to cell size for human bulbar conjunctival cells. Methods Impression cytology samples were taken from the nasal side of the intra-palpebral zone of the bulbar conjunctival surface from 20 young adult white European males, half of whom were successful daily soft contact lens wearers. A Millcell ®-CM filter was used, after topical anaesthesia with oxybuprocaine 0.4%, which was stained with Giemsa and colour images taken at 400× magnification by light microscopy. The images were graded and also a 35 mm was prepared. From the projected image, an overlay method was used to outline the borders such that the cell and nucleus areas could be measured by planimetry. Results The group mean cell area values were 267 ± 59 μm 2 ( n = 10, ±S.D.) and 1028 ± 357 μm 2 for the non-contact lens wearers and contact lens wearers, respectively. The cell nucleus areas were 64 ± 11 μm 2 and 99 ± 19 μm 2, respectively. Both the cell areas and nucleus area values were statistically different between the two groups ( p < 0.001). Conclusions These studies confirm that soft contact lens wear can result in cell enlargement (squamous metaplasia) of the bulbar conjunctival cells. With this cell enlargement, the nucleus-to-cytoplasm ratio also changes, but the nucleus size generally increases (rather than decreases).

Impression cytology of a case of conjunctival metaplasia associated with oral carbamazepine use?

Purpose To report a case of conjunctival squamous metaplasia associated with oral carbamazepine use. Methods Following completion of an ocular comfort questionnaire, biomicroscopy and a phenol red thread test, impression cytology from the inter-palpebral zone (nasal) of the bulbar conjunctival surface was undertaken using a Millcell ®-CM filter after topical anaesthesia with oxybuprocaine 0.4%. The filter was stained with Giemsa and colour images taken at 400× magnification by light microscopy. The images were graded and also a 35 mm was prepared. From the projected image, an overlay method was used to outline the borders such that the cell and nucleus area, and the longest and shortest dimensions could be measured by planimetry. Results A male subject, added 22 years, presented with slight conjunctival injection but no substantial symptoms and only slight surface staining with fluorescein. The subject reported use of oral carbamazepine (200 mg, b.d.s.). Impression cytology showed large sheets of squamous cells (grade 2–3) with few goblet cells. The average cell area was 1509 μm 2, the long:short dimension ration averaged 1.42 and the average nucleus/cytoplasm (N/C) value was just 0.092 (or 1:11.5 as a ratio). Conclusions Since the drug has been reported to be excreted in the tear film, and with no other risk factors (such as contact lens wear, smoking or dry eye disease), the squamous metaplasia is attributed to the use of carbamazepine.

Longitudinal analysis of varicella-zoster virus DNA on the ocular surface associated with herpes zoster ophthalmicus

PURPOSE: Longitudinal analysis of varicella-zoster virus DNA on the ocular surface of patients with herpes zoster ophthalmicus. METHODS: Clinical specimens were obtained from the bulbar conjunctival surface with a cotton-tipped swab at weekly intervals for 6 consecutive weeks from 21 patients with acute ophthalmic zoster with a skin rash duration of less than 7 days. All patients received oral valacyclovir 1000 mg three times daily for 10 days without additional corticosteroids. The swabs were analyzed by means of polymerase chain reaction for the presence of varicella-zoster virus and herpes simplex virus type 1 DNA. Conjunctival swabs were also obtained from a control group of 20 patients with cataract. RESULTS: On inclusion, varicella-zoster virus DNA was present on the ocular surface of 19 of the 21 patients. Six varicella-zoster virus DNA–positive patients had no signs of ocular inflammation. All control swabs were negative for both varicella-zoster virus and herpes simplex virus DNA. The duration of varicella-zoster virus DNA detection from rash onset varied from 2 to 34 days. The number of days between the onset of herpes zoster skin rash and the latest positive varicella-zoster virus DNA test was significantly longer in patients whose age was equal to or above the median age of 66 years than in the younger patients (Mann-Whitney test: P = .0004). At 6-week follow-up, all conjunctival swabs were negative for varicella-zoster virus DNA. However, at that time, the eyes of seven patients were still inflamed. CONCLUSION: The duration of varicella-zoster virus DNA shedding in herpes zoster ophthalmicus is highly variable and age dependent, and is probably related to the host immune response.

Further analysis of the size and shape of cells obtained by impression cytology from the exposed portion of the human bulbar conjunctiva

Summary Purpose: To assess whether the size of the cells obtained by conjunctival impression cytology can be quantitatively assessed by measurement of the longest dimension of the cells. Methods: Under topical benoxinate anaesthesia, cells were removed from the normally exposed nasal bulbar conjunctival surface using a 0.4 μm pore diameter filter (Biopore® filter; type Millcell®‐CM). The filters were stained with haematoxylin after ethanol denaturation, photographed at 40× magnification, and 35 mm slides prepared. An optical overlay method was used to outline the borders of sets of 30–35 contiguous cells on each image. The cell area, longest and shortest dimensions were measured by planimetry to an accuracy of ±3%. Results: Analyses of 20 sets of samples, from individuals aged 21 to 48 years and without clinically significant ocular surface disease, revealed a median cell area of 133 μm2 (n=621, range 46–1602 μm2; average 212 μm2), a median longest dimension of 13.9 μm (range 6.6–68.8 μm; average 16.9 μm) and a shorter dimension of 10.0 μm (range 4.7–43.0 μm; average 11.9 μm); the distributions of values indicated bimodality. Most cells had a long:short ratio (L:S ratio) value between 1.00 and 1.80, but 11.9±6.1% of the cells had L:S ratios between 1.80 and 4.60. The overall relationship between the longest dimension and the area of the cells was non‐linear, with cells having larger L:S ratios having disproportionately smaller areas. Conclusions: The superficial conjunctival cells are small, and their longest dimensions are systematically related to area. Analyses of cell shape indicate further possible ways of identifying different cells on the bulbar conjunctiva. Compared to literature values, there is a substantial overlap in longest dimensions of the conjunctival cells with those of cells that can be collected off the corneal surface. This means that superficial conjunctival and corneal cells cannot be distinguished simply on the basis of measurements of the long dimension.

Further analysis of the size and shape of cells obtained by impression cytology from the exposed portion of the human bulbar conjunctiva

To assess whether the size of the cells obtained by conjunctival impression cytology can be quantitatively assessed by measurement of the longest dimension of the cells. Under topical benoxinate anaesthesia, cells were removed from the normally exposed nasal bulbar conjunctival surface using a 0.4 micron pore diameter filter (Biopore filter; type Millcell-CM). The filters were stained with haematoxylin after ethanol denaturation, photographed at 40 x magnification, and 35 mm slides prepared. An optical overlay method was used to outline the borders of sets of 30-35 contiguous cells on each image. The cell area, longest and shortest dimensions were measured by planimetry to an accuracy of +/- 3%. Analyses of 20 sets of samples, from individuals aged 21 to 48 years and without clinically significant ocular surface disease, revealed a median cell area of 133 micron 2 (n = 621, range 46-1602 micron 2; average 212 micron 2), a median longest dimension of 13.9 microns (range 6.6-68.8 microns; average 16.9 microns) and a shorter dimension of 10.0 microns (range 4.7-43.0 microns; average 11.9 microns); the distributions of values indicated bimodality. Most cells had a long:short ratio (L:S ratio) value between 1.00 and 1.80, but 11.9 +/- 6.1% of the cells had L:S ratios between 1.80 and 4.60. The overall relationship between the longest dimension and the area of the cells was nonlinear, with cells having larger L:S ratios having disproportionately smaller areas. The superficial conjunctival cells are small, and their longest dimensions are systematically related to area. Analyses of cell shape indicate further possible ways of identifying different cells on the bulbar conjunctiva. Compared to literature values, there is a substantial overlap in longest dimensions of the conjunctival cells with those of cells that can be collected off the corneal surface. This means that superficial conjunctival and corneal cells cannot be distinguished simply on the basis of measurements of the long dimension.

Sodium Hyaluronate and Polyvinyl Alcohol Artificial Tear Preparations

An unpreserved artificial tear substitute containing 0.1% sodium hyaluronate was compared with a preparation containing 1.4% polyvinyl alcohol and 0.5% chlorobutanol in a controlled, double-masked, randomized study in patients with moderately severe keratoconjunctivitis sicca. Patients were evaluated initially, at 1, 4, and 8 weeks. The dry-eye status was evaluated by means of tear-film osmolality, tear breakup time, rose bengal staining, Schirmer's test (without anesthesia), and ocular surface-impression cytology. In general, neither preparation was found to be superior to the other. In both study groups, the mean tear-film osmolality and rose bengal staining score improved over the eight-week study, but the degree of squamous metaplasia of the bulbar conjunctival surface, as shown by impression cytology, did not change significantly.

Conjunctival Resection Treatment And Ultrastructural Histopathology Of Superior Limbic Keratoconjunctivitis

Four patients with symptomatic superior limbic keratoconjunctivitis underwent resection of the superior bulbar conjunctiva. One of these patients also underwent a tarsal conjunctival resection in the other eye. Three of the patients had previously been treated by various regimens without resolution; the fourth had had no prior treatment. All four patients had immediate and continued relief of the ocular symptoms after the superior bulbar conjunctiva was excised. The patient who underwent tarsal conjunctival resection experienced only short-term relief. We studied the conjunctival tissue by light and transmission electron microscopy. Both techniques revealed abnormalities related to the bulbar conjunctival surface with keratinization of the epithelium, acanthosis, degeneration of the nuclei, and intracellular accumulation of glycogen. Inflammatory cells were minimally present. The tarsal conjunctiva appeared essentially normal.