Corneal thickness in trachomatous dry eye

PURPOSE

To investigate the effect of severe desiccation on corneal thickness in scarring trachoma by comparing the thickness of normal and trachomatous dry eye corneas.

METHODS

Ultrasonic pachymetry was used to measure the corneal thickness at nine points in the central and peripheral cornea (superior, superonasal, nasal, inferonasal, inferior, inferotemporal, temporal, superotemporal) in 45 eyes of 27 patients with trachomatous dry eye and 54 eyes of 31 normal subjects.

RESULTS

The average thickness of the nine sites in the central and midperipheral cornea was significantly less in trachomatous dry eyes than normal eyes. The superior cornea was the thickest area in both groups, measuring 574.03+/-31.62 microm in trachomatous dry eyes and 611.33+/-34.99 microm in normal eyes (p<0.001). The centre of the cornea was the thinnest, measuring 510.43+/-32.12 microm in trachomatous dry eyes and 546.27+/-36.20 microm in normal eyes (p<0.001).

CONCLUSIONS

The thickness of the central and midperipheral cornea was significantly reduced in patients with trachomatous dry eye. The chronic state of severe desiccation, tear film instability and increased immune activation in trachomatous dry eye may contribute to this thinning.

Experimental intravitreal application of trovafloxacin in rabbits

This study was performed to examine the retinal toxicity of trovafloxacin, a broad-spectrum fourth-generation fluoroquinolone, in rabbit eyes after intravitreal injection. The left eyes of 20 albino rabbits were divided into four groups, and each was injected intravitreally with 0.1 ml of trovafloxacin in a 50-microg, 100-microg, 250-microg or 500-microg concentration. The right eyes of these rabbits served as control and received normal saline solution. Retinal function was assessed from the electroretinogram (ERG), and retinal structure was also examined by ophthalmoscopy and histologic study (light microscopy). The intravitreal injections of 50 microg, 100 microg, and 250 microg trovafloxacin did not significantly change the ERG a-wave, b-wave or the oscillatory potential throughout the follow-up period of 4 weeks. While no ERG changes were observed at 4 weeks after injection, in the 3 eyes that received trovaloxacin 500 microg/0.1 ml, the a-wave amplitudes showed a diminution of 56-49% and those of b-waves one of 53-44% of the preinjection amplitudes at 4 weeks after injection, but oscillatory potentials remained unchanged in the other 2 rabbits intravitreally injected with 500 microg trovafloxacin. However, in none of the injected eyes and the control eyes in all groups were ophthalmoscopically visible fundus changes and histologic abnormality observed. The results suggest that intravitreally injected trovafloxacin at a dose of up to 500 microg is nontoxic to the rabbit retina. If future studies in other species confirm our findings, intravitreal trovafloxacin may be a good alternative in the treatment and prevention of clinical bacterial endophthalmitis.

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.

Tear functions in patients with pinguecula

PURPOSE

To investigate the tear flow, tear film stability and condition of mucus in patients with pinguecula.

METHODS

The Schirmer I and ferning tests were performed and break-up time (BUT) was determined in 57 patients with pinguecula [random eyes; 34 males and 23 females, 18 to 70 years of age (mean +/- SD: 39.1 +/- 13.5 years)] and in 57 age-matched subjects (control) [random eyes; 35 males and 22 females, 11 to 70 years of age (mean +/- SD: 37.8 +/- 15.2 years)], and the test results were statistically analysed.

RESULTS

The mean Schirmer test value was 22.72 +/- 12 mm in the eyes with pinguecula and 22.7 +/- 8.5 mm in the control eyes. There was no statistically significant difference (t = 0.01, p = 0.99) between the groups. The mean BUTs were 11.42 +/- 6.89 s in the eyes with pinguecula and 15.46+/-5.85 s in the control eyes. Comparison of BUTs between the groups revealed a statistically significant difference (t = 3.37, p = 0.0010). Also, ferning types were found to be significantly abnormal in the eyes with pinguecula (p < 0.01).

CONCLUSION

The alteration in the mucin layer is a possible change inducing pinguecula formation, or it may reflect an already existing pathology in the cells on the ocular surface.

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 patients awaiting 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 topical anesthetic, proparacaine, demonstrates antibacterial effects on the conjunctival flora.

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 degrees 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 photovaporization 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.

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.

Effect of taurolidine on the normal eyelid and conjunctival flora

PURPOSE

The effectiveness of the topical taurolidine was evaluated in eradicating or reducing microorganisms in the normal flora of human eyes in a randomized controlled study and analyzed also the irritating effects of taurolidine on the ocular surface.

METHODS

One hundred and twenty eyes of 110 patients awaiting cataract surgery were randomly divided into four groups consisting of 30 eyes each. The first group received 0.05% taurolidine, the second received 0.3% gentamicin, the third received vehicle eyedrops and the fourth received saline to the preoperative eye four times daily for two days. Cultures were obtained from the eyelids and conjunctivas of all subjects prior to the therapy and again at the end of 48 hours. Micro-biological identification and colony counts were performed by standard laboratory methods, and the results were compared. The patients were clinically evaluated for symptoms and signs at the end of therapies.

RESULTS

Taurolidine and gentamicin produced a significant decrease from the basal bacteriological state: the number of colonies (p < 0.01 for taurolidine, p < 0.01 for gentamicin) was reduced by both agents. Staphylococcus epidermidis was the most common microorganism isolated before therapy, and the number of its colonies was significantly reduced in taurolidine-treated (p < 0.001) and gentamicin-treated (p < 0.01) subjects. There was no significant difference in terms of the irritating effects for all therapies tested (p > 0.05).

CONCLUSIONS

Taurolidine solution with its unique properties is an effective antimicrobial agent for reducing the number of bacteria in the flora of the eye. Taurolidine appears to be well tolerated and offers promise as a potential new antimicrobial drug.

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.

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.