Sezin Karadede

A Survey of Trachoma: The Histopathology and the Mechanism of Progressive Cicatrization of Eyelid Tissues

The aim of this study is to demonstrate the spectrum of conditions encompassed by the term ‘trachomatous cicatrization of eyelid tissue’, to discuss the mechanisms of scar tissue formation and to describe sequelae in this potentially blinding condition. Specimens of eyelid tissues were taken from 27 upper eyelids of 21 patients with entropion who underwent surgical procedures and 2 post-mortem upper eyelids with severe trachomatous entropion. Upper palpebral conjunctival swabs and biopsy specimens were taken from 5 patients with active trachoma and they were examined by fluorescence microscopy and routine histopathological methods. Conjunctival impression cytology samples were collected in all patients. In specimens taken from patients with active trachoma the inflammatory infiltrate was organized as lymphoid follicles in the underlying stroma and impression cytology showed cytoplasmic elementary bodies. In specimens taken from patients with scarring trachoma light microscopy studies showed subepithelial fibrous membrane formation, squamous metaplasia and loss of goblet cells, pseudogland formation in conjunctiva, degeneration of orbicularis oculi muscle fibres, subepithelial vascular dilatation, localized perivascular amyloidosis and subepithelial lymphocytic infiltration. Accessory lachrymal glands and the ducts of glands were compromised by subepithelial infiltration and scarring. The contraction of the subepithelial fibrous tissue formed by collagen fibres and anterior surface drying are the main factors contributing to the chronic cicatrization and entropion formation.

Increase of free oxygen radicals in aqueous humour induced by selective Nd:YAG laser trabeculoplasty in the rabbit

Purpose To investigate the impact of selective Nd:YAG laser trabeculoplasty on free oxygen radicals and antioxidant enzymes of the aqueous humour in the rabbit. Methods One eye of 18 rabbits was subjected to 360° selective laser trabeculoplasty (LT) with a frequency-doubled Nd:YAG laser (532 nm). The anterior chamber aqueous humour was aspirated 3, 12 hours and 1, 3, 7, 10 days after treatment. Lipid peroxide (LPO) and glutathione S transferase (GST) levels and superoxide dismutase (SOD) activities of aqueous humour were measured. Results Concentrations of LPO in the aqueous humour of the treated eyes were significantly higher than the untreated eyes until the 7th day. Aqueous SOD activity significantly decreased 3 hours after LT and remained low until day 7. Aqueous GST levels were significantly decreased between 12 hours and 7 days after the LT. Conclusions Selective LT was followed by an immediate increase in the aqueous humour LPO concentration and decreases of SOD and GST in the rabbit, probably due to photo-vaporization and photodisruption caused by the frequency- doubled Nd:YAG laser. The increased aqueous LPO levels suggest that free oxygen radicals are formed in the pigmented trabecular meshwork during LT, and may be responsible for the inflammatory complications of this procedure.

The Effects of Bupivacaine and Lidocaine on the Corneal Endothelium when Applied into the Anterior Chamber at the Concentrations Supplied Commercially

Purpose: To investigate the direct toxic effects of bupivacaine HCl 0.5% and lidocaine HCl 2%, two commonly used injectable local anesthetic agents, on the corneal endothelium when applied intracamerally. Methods: Two groups were formed, each consisting of 12 pigmented rabbits, and 0.2 ml of the anesthetic agent were injected intracamerally into the right eyes. The central corneal thicknesses and corneal clarities were evaluated preoperatively and at 3, 6, 9, 12 h and 1, 3, 7 days postoperatively. While the central corneal thicknesses were evaluated by ultrasonic pachymetry, the corneal opacification scored between 0 and 3 was assessed by biomicroscopic examination and photographs. Results: Both bupivacaine and lidocaine caused corneal thickening in the 3- to 12-hour measurements. In addition, there was significant corneal opacification in both groups in the 3-hour and 3-day measurements. The corneal thickening and corneal opacification determined during 3- and 6-hour measurements in the eyes which received intracameral bupivacaine were significantly higher than those determined in the lidocaine-injected group. In both groups, the corneal thickness and corneal clarity scores returned to the preoperative values on the 1st and 7th days, respectively. Conclusions: When applied into the anterior chamber at the concentrations supplied commercially, both bupivacaine and lidocaine cause statistically significant corneal thickening and clinically significant corneal opacification. It should be noted that the injection of these agents into the anterior chamber during the operation at the concentrations supplied commercially may be a potential risk factor for endothelial injury.

The treatment of severe trachomatous dry eye with canalicular silicone plugs.

Purpose To evaluate the effects of temporary canalicular occlusion with silicone plugs on trachomatous dry eye patients who were on maximal tolerable medical therapy.Methods Forty-four trachomatous dry eye patients who had Schirmer testing with topical anaesthetic measuring 5 mm or less and a tear film break-up time of 5 s or less were included. After the lacrimal efficiency test with dissolvable collagen punctal plugs, silicone canalicular plugs were placed in 22 trachomatous dry eye patients. The other 22 patients in the untreated control group were allowed to continue their medical therapy. Pretreatment and post-treatment evaluations included subjective patient assessment, rose Bengal and fluorescein staining, tear film break-up time, Schirmer testing, conjunctival impression cytology and goblet cell counting.Results Six months after plug placement, 18 eyes (82%) of 22 patients had subjective improvement and all these patients successfully wore plugs for at least 6 months. There were statistically significant differences between the pretreatment and post-treatment test results including rose Bengal and fluorescein staining scores, tear film break-up times and Schirmer testing measurements. Impression cytology showed improvement of squamous metaplasia in 17 eyes (77%). Eight of the patients (36%) were able to decrease dependency on topical therapy. Ten of the patients (45%) completely stopped using artificial tears. There were statistically significant differences between the two groups in the total symptom scores, staining scores, tear film break-up time, Schirmer testing, impression cytology scores and goblet cell counts.Conclusion In cases where topical tear supplementation is insufficient to relieve the signs and symptoms of severe dry eye and the lacrimal puncta have not already been closed by the trachomatous cicatrising process, occlusion of the canaliculi may be useful to prevent drainage of both natural and artificial tears. Canalicular occlusion improves the objective signs and subjective symptoms and may significantly decrease dependency on tear supplements in selected patients.

The antibacterial effect of topical anesthetic proparacaine on conjunctival flora

Purpose: To investigate the antibacterial effect of topical anesthetic proparacaine on conjunctival flora.Methods: One hundred and forty-four eyes of 72 patientsawaiting cataract surgery were included in the study. A commercially available solution of proparacaine, preserved with benzalkonium chloride 0.01%, was instilled in one eye of all subjects while the vehicle solution, including the same concentration of preservative in aqueous solution, was administered to the other eye. Conjunctival cultures were taken from all eyes before and 15 minutes after the instillation of proparacaine and the vehicle.Results: Of the 144 eyes, 76 (52.8%) had positive-conjunctival cultures with the most commonly isolated organisms being coagulase-negative staphylococci in each group. Of the 76 culture-positive eyes, 40 (52.6%) received proparacaine and 36 (47.4%) the vehicle preparation. Fifteen minutes after the instillation of proparacaine and the vehicle eyedrops, four eyes (10%) and 12 eyes (33.3%) had culture-positive conjunctival smears, respectively. Proparacaine significantly reduced the number of culture-positive eyes (p = 0.0003), in contrast to the vehicle (p = 0.21).Conclusion: A topicalanesthetic, proparacaine, demonstrates antibacterial effects on the conjunctival flora.

Three-Day Course of Oral Azithromycin vs Topical Oxytetracycline/Polymyxin in Treatment of Active Endemic Trachoma

PURPOSE The aim of this study on endemic trachoma was to carry out a comparison of azithromycin (3-day course, oral dose of 10 mg/kg per day) with conventional treatment (topical oxytetracycline/polymyxin ointment; twice a day for 2 months) in a rural area near Sanliurfa, Turkey. METHODS Ninety-six subjects with active trachoma were randomly assigned conventional or azithromycin treatment. Subjects were examined 1, 2, 3, and 6 months after the start of treatment. Clinical findings were recorded for each eye. Swabs were taken from upper eyelids 3 and 6 months after the start of treatment for direct fluorescein antibody test. RESULTS By six-month follow-up, trachoma had resolved clinically in 43 (89.58%) of the 48 subjects who received azithromycin, compared with 33 (68. 75%) of the 48 who were treated conventionally. Microbiological success rates (direct fluorescein antibody test negativity) were 83. 33% in the azithromycin group and 62.50% in the conventional therapy group. Compliance with both treatments was good. By 6 months, 14.58% of the subjects in azithromycin group and 33.33% of the subjects in the topical treatment group were reinfected. There were significant differences in the efficacy of the treatment effects and the re-emergence of disease between the two treatment groups. Azithromycin was well-tolerated. CONCLUSIONS These results indicate that azithromycin may be an effective alternative for patients with active trachoma. As a systemic treatment, a 3-day course oral dose has important potential for trachoma control.

A study on the toxicity of intravitreal levofloxacin in rabbits

Purpose. To investigate the retinal toxicity of different doses of intravitreal injections of levofloxacin in a rabbit model, which is the levorotatory component of ofloxacin and approximately twice as potent as ofloxacin and highly active in vitro against gram-positive and -negative bacteria, and anaerobic bacteria including many ocular pathogens. Methods. Sixteen albino rabbits were used in this study, and divided four groups. Levofloxacin in doses of 50, 100, 250 and 500 µg was injected into the midvitreous of rabbits left eyes. The other eye served as a control and received normal saline solution. Indirect ophthalmoscopy, electroretinography (ERG) and light microscopy were used for retinal toxicity of levofloxacin. ERGs were recorded before injection and at 1 st day, 1 st, 2 nd and 4 th weeks. At the end of follow-up period, the rabbits were killed and the eyes were enucleated for histologic evaluation. Results. Intravitreal injections of 50, 100, 250 and 500 µg levofloxacin did not cause any deterioration of the a-wave, b-wave or oscillatory potentials of ERG throughout the follow-up period of 4 weeks. No evidence of retinal toxicity was observed by indirect ophthalmoscopy and light microscopy in any case. Conclusions. In therapeutic doses of 500 µg or less, intravitreal levofloxacin does not have retinal toxicity in rabbit eyes and this dose was well above the MIC 90 values of ocular pathogens that cause endophthalmitis. If future studies in other species confirm our findings, intravitreal levofloxacin may be a potentially important drug in the treatment and prevention of clinical bacterial endophthalmitis.

Oedematous Corneal Response of the Fellow Control Eye to Lotrafilcon A and Vifilcon A Hydrogel Contact Lenses in the Rabbit

Purpose: To compare central corneal swelling after 24 h in eyes wearing Lotrafilcon A (high Dk silicone hydrogel) and Vifilcon A (low Dk hydrogel) lenses and the fellow control eyes of rabbits. Methods: 24 New Zealand albino rabbits, free of corneal and conjunctival disease, were anaesthetised with ketamine and xylazin. In 12 rabbits, the right eye was fit with the high Dk Lotrafilcon A silicone hydrogel lens. In the other 12 rabbits, the right eye was fit with the low Dk Vifilcon A hydrogel lens, whereas the left eyes were kept as control eyes. Thereafter, the lens-fitted eyes had partial tarsorrhaphy that left a central gap of approximately 4 mm in length. After 24 h the eyelids were opened and the lenses removed. Central corneal thickness was measured using an ultrasonic pachymeter (Mentor O&O-Advent). Results: Central corneal oedema induced by Vifilcon A lens was significantly higher than that with the Lotrafilcon A lens (p < 0.0001). The oedema of the fellow eyes paired with the Vifilcon A lens-wearing eyes was also higher than that of the fellow eyes paired with the Lotrafilcon A lens-wearing eyes (p < 0.01). Conclusions: The Lotrafilcon A lens induced significantly less corneal oedema than the Vifilcon A lens. Corneal oedema of the fellow eyes appears to be influenced by the swelling of the contralateral lens-wearing eyes. The oedema of the fellow control eye was significantly lower when there was less oedema in the contralateral eye wearing a high Dk silicone hydrogel lens. This may be a sympathetic physiological response. The presence of silicone in the high Dk hydrogel lens may suppress corneal oedema in the lens-wearing eye, thus affecting the fellow eye.

Flash visual evoked potentials and electroretinograms in migraine

Possible changes in flash visual evoked potentials (F-VEPs) and electroretinograms (ERGs) during migraine without aura (MO) were investigated. This study was carried out in a group of 22 patients with MO during the headache period (group 1), a group of 26 patients with MO during the headache-free period (group 2), and 24 sex- and age-matched controls. A complete routine ophthalmologic examination, F-VEPs, and ERGs were performed on all subjects. Ophthalmologic examinations of all subjects were normal. No difference was found between the groups in mean latencies and amplitudes of VEP-P2 and ERG-rod responses. However, the wavelet index of ERG-oscillatory potentials (OPs) was significantly lower in group 1 than in group 2 and the control group (p = 0.02). Migraine headache decreased the wavelet index of ERG-OPs. This effect may be associated with the depletion of serotonin during the migraine headache period.

Ketorolac-Tobramycin Combination vs Fluorometholone-Tobramycin Combination in Reducing Inflammation Following Phacoemulsification Cataract Extraction With Scleral Tunnel Incision

OBJECTIVE The objective of this study was to compare the efficacy of ketorolac-tobramycin combination with fluorometholone-tobramycin combination in the control of ocular inflammation after endocapsular phacoemulsification cataract surgery with scleral tunnel incision. PATIENTS AND METHODS This was a prospective, randomized, investigator masked, 2-week, single-center study. Ocular examinations were carried out preoperatively and postoperatively on days 1 (baseline), 2, 3, 7, and 14. There were 60 patients (30 in each treatment group) undergoing uncomplicated cataract-lens implant surgery enrolled and randomized in the study. The baseline parameters were similar in the two study groups. At each visit comprehensive ocular examinations were performed and a 4-point (0 to 3) grading system was used to record findings of the burning/stinging sensation, blurred vision, ocular discomfort, conjunctival hyperemia, anterior chamber flare, and anterior chamber cells. RESULTS There was no statistically significant difference between the treatment groups in the findings of the ocular inflammation at any of the postoperative visits. Both treatments were equally well tolerated. CONCLUSIONS This study suggests that ketorolac may be an alternative to some corticosteroids (fluorometholone). It is generally accepted that fluorometholone is not as potent an anti-inflammatory as prednisolone the most commonly used steroid following cataract extraction.