The Development of Corneal Opacity, Increased Hydration and Increased Thickness in Isolated Porcine Corneas in Response to Timolol Maleate Solutions Containing Various Preservatives

1996 ◽  
Vol 24 (1) ◽  
pp. 21-29
Author(s):  
Haruyoshi Igarashi ◽  
Chiharu Sato ◽  
Yu Chiba ◽  
Katsuhiro Ogawa ◽  
Michio Kojima
Keyword(s):  
Incubation Period ◽  
Benzalkonium Chloride ◽  
Corneal Thickness ◽  
Corneal Opacity ◽  
Timolol Maleate ◽  
Corneal Toxicity

The effects of 0.125%, 0.25% and 0.5% timolol maleate on the opacity, thickness and hydration of isolated porcine corneas were determined. The effects of adding 0.005% benzalkonium chloride, 0.5% chlorbutanol or a combination of 0.026% methyl p-hydroxybenzoate, 0.014% propyl p-hydroxybenzoate and 0.2% chlorbutanol to the timolol solutions were also assessed. Over a 4-hour incubation period, a concentration-related opacity developed in the presence of timolol alone, and was not greatly affected by the addition of the p-hydroxybenzoate mixture. However, the addition of benzalkonium chloride or the higher concentration of chlorbutanol markedly increased opacity. Corneal thickness increased significantly in the presence of 0.25% and 0.5% timolol and even further in the presence of the preservatives, chlorbutanol being the most potent. Hydration increased slightly with time and also in the presence of each of the preservatives. The need to achieve a balance between possible corneal toxicity and effective batericidal activity is discussed.

The Use of an Opacitometer to Compare the In Vitro Cornea Opacifying Effects of Timolol With and Without Benzalkonium Chloride

1991 ◽  
Vol 19 (2) ◽  
pp. 263-270
Author(s):  
Haruyoshi Igarashi ◽  
Yasunaga Katsuta ◽  
Yoshiharu Nakazato ◽  
Tohru Kawasaki
Keyword(s):  
Benzalkonium Chloride ◽  
Additive Effects ◽  
Timolol Maleate ◽  
Epithelial Surface ◽  
Endothelial Surface ◽  
Draize Test ◽  
Corneal Opacities

We have evaluated a new in vitro opacitometer method as an alternative to the in vivo Draize test for ocular irritancy. Several concentrations of timolol maleate (timolol) with or without 0.005% benzalkonium chloride were applied to porcine isolated corneas which were either intact or with the epithelium, endothelium, or both epithelium and endothelium removed. Corneal opacities were measured using an opacitometer. In general, timolol with benzalkonium chloride caused a greater degree of opacity to develop in the cornea than did timolol alone. At the lower concentrations of timolol, the increased opacity probably represented additive effects of the two compounds. However, at the highest concentration of timolol (5 x 10 2M), there was an enhanced opacification in the presence of benzalkonium chloride, which may have been due to an increase in penetration, particularly through the epithelium. Timolol caused a greater degree of opacity to develop in the isolated intact porcine corneas when the drug was applied to the endothelial surface, than when applied to the epithelial surface or to both the epithelial and endothelial surfaces. However, timolol with benzalkonium chloride caused a greater degree of opacity in the intact cornea, when the drug was applied to both surfaces than when it was applied only to the epithelial or the endothelial surface.

scholarly journals Benzalkonium chloride corneal toxicity post-cataract surgery

2020 ◽  
Vol 17 (1) ◽  
pp. 56-60
Author(s):  
Keith Ong ◽  
Leonard Ong
Keyword(s):  
Cataract Surgery ◽  
Benzalkonium Chloride ◽  
Corneal Stroma ◽  
Eye Drops ◽  
Descemet's Membrane ◽  
Corneal Toxicity ◽  
Descemet’S Membrane ◽  
Free Steroid

Two patients with presumed benzalkonium chloride (BAK) corneal toxicity after routine cataract surgery are presented. Patient 1 had corneal stroma and Descemet’s membrane folds. Patient 2 had moderate superficial punctate epithelial erosions (SPEE). They were on Chlorsig, Maxidex, and Acular eye drops tds postoperatively. The corneas of these two patients improved when BAK was removed or minimized from the postoperative eye drop regimen. Two vials of 1 ml dexamethasone 4mg/ml for injection were added to Chlorsig 10 ml bottle to substitute for Maxidex eye drops. BAK toxicity should be suspected when the cornea is not as clear as expected postoperatively. A practical way to eliminate BAK from postoperative eye drops is described, and would be useful until pharmaceuticals mass-produce BAK-free steroid eye drops economically.

scholarly journals Effect of Acute Increases in Intraocular Pressure on Corneal Pachymetry in Rabbit Eyes Treated with Timolol Maleate

2018 ◽  
Vol 12 (1) ◽  
pp. 314-321
Author(s):  
Cristina Sánchez-Barahona ◽  
Gema Bolívar ◽  
Dimitrios G. Mikropoulos ◽  
Anastasios G. Konstas ◽  
Miguel A. Teus
Keyword(s):  
Intraocular Pressure ◽  
Anterior Chamber ◽  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Rabbit Model ◽  
Controlled Study ◽  
Control Group ◽  
Study Group ◽  
Timolol Maleate

Objective: To evaluate in an in vivo rabbit model, the effect of topical timolol maleate therapy on the central corneal thickness response to acute intraocular pressure increases. Method: In this prospective and interventional controlled study, the central corneal thickness and intraocular pressure were measured in vivo in 12 rabbit eyes treated with topical timolol maleate for 1 month and in 12 controls at baseline, and after the intraocular pressure (measured by direct cannulation of the anterior chamber) was increased to 15 and 30 mmHg using a forced saline infusion into the anterior chamber. Results: There were no significant differences in the basal central corneal thickness values (control group, 373.2±12.9 µm; study group, 377.5±19.2 µm, p=0.5) or the central corneal thickness values when the intraocular pressure was increased to 15 mmHg (control group, 335.2±14.3 µm; study group, 330.0±32.1 µm, p=0.6) and to 30 mmHg (study group, 318.8±25.3 µm; control group, 329.8±21.0 µm, p=0.3). Conclusion: Rabbit corneas treated with topical timolol maleate for 1 month did not show a strain response to acute intraocular pressure increases that differed from control eyes. This is in contrast to a previous finding in which rabbit eyes treated with prostaglandin analogues had a greater decrease in central corneal thickness in response to a sudden intraocular pressure increase compared with untreated corneas.

scholarly journals MSCs helped reduce scarring in the cornea after fungal infection when combined with anti-fungal treatment

2019 ◽  
Author(s):  
Yue Zhou ◽  
Yuqing Chen ◽  
Suiyue Wang ◽  
Fangyuan Qin ◽  
Wang liya
Keyword(s):  
Fungal Infection ◽  
Second Harmonic ◽  
Corneal Thickness ◽  
Corneal Opacity ◽  
Scar Formation ◽  
Control Group ◽  
Eye Drops ◽  
Corneal Tissue ◽  
Related Factors ◽  
Corneal Scar

Abstract Background Fungal Keratitis (FK) is an infective keratopathy with extremely high blindness rate. The damaging effect of this disease is not only the destruction of corneal tissue during fungal infection, but also the cornea scar formed during the healing period after infection control, which can also seriously affect a patient's vision. The purpose of the study was to observe the effect of umbilical cord mesenchymal stem cells (uMSCs) on corneal scar formation in FK. Methods The FK mouse model was made according to a previously reported method. Natamycin eye drops were used for antifungal treatment 24 hours after modeling. There are four groups involved in the study, including control group, FK group, vehicleinj FK group and uMSCsinj FK group. Mice in uMSCsinj FK group received repeated subconjunctival injections of uMSCs for 3 times at the 1d, 4d and 7d after FK modeling. At 14d, 21d and 28d after trauma, clinical observation, histological examination, second harmonic generation and molecular assays were performed. Results The uMSCs topical administration reduced corneal scar formation area and corneal opacity, accompanying with decreased corneal thickness and inflammatory cell infiltration, following down-regulated fibrotic-related factors α-SMA, TGFβ1, CTGF, and COLI and finally inhibited phosphorylation of TGFβ1/Smad2 signaling pathway during FK corneal fibrosis. Conclusion The results confirmed that uMSCs can improve corneal opacity during the scar formation stage of FK, and exert anti-inflammatory and anti-fibrotic effects..

scholarly journals Comparative efficacy study of brimonidine tartrate 0.15% and timolol maleate 0.5% ophthalmic solution (benzalkonium chloride free) versus Brimolol® (with benzalkonium chloride) following single ocular instillation in New Zealand white rabbits

2020 ◽  
Vol 9 (7) ◽  
pp. 1050
Author(s):  
Amit Thavkar ◽  
Sateesh Kumar Chauhan ◽  
Subhas Bhowmick ◽  
Vinod Burade
Keyword(s):  
Intraocular Pressure ◽  
New Zealand ◽  
Repeated Measures ◽  
Benzalkonium Chloride ◽  
Ophthalmic Solution ◽  
Eye Drops ◽  
Timolol Maleate ◽  
Repeated Measures Analysis ◽  
Brimonidine Tartrate ◽  
Ophthalmic Solutions

Background: Benzalkonium chloride (BKC) is the most used preservative in topical eye drops but it causes effects such as dry eye and trabecular meshwork degeneration. Polyhexamethylene biguanide (PHMB) is a polymeric biguanide is a less harmful preservative used in ophthalmic solutions. The objective of this study to com-pare the efficacy of PHMB preserved versus BKC preserved ophthalmic solutions containing brimonidine tartrate and timolol maleate on intraocular pressure (IOP) following single ocular instillation in New Zealand white (NZW) rabbits.Methods: This study was conducted on 12 normotensive male NZW rabbits (2.9-3.6 kg) between 6-9 months of age. Animals received single ocular instillation of 35 µl ophthalmic solution containing brimonidine tartrate 0.15 %w/v and timolol maleate 0.5% w/v with PHMB as preservative (n=6, test) or BKC as preservative (n=6, reference) as per the randomization. Intraocular pressure (IOP) was measured before and 2, 4, 6, 8 and 24 hours after instillation using a pneumatonometer. Percentage change in IOP from pre-instillation values were calculated. Changes in IOP were analysed using the repeated-measures analysis of variance followed by Bonferroni post-test.Results: Single ocular instillation of PHMB and BKC formulations show significant IOP reduction up to 6 hours as compared with baseline (p<0.05). Reduction in IOP was 35.8% and 32.0% at 2 hours with PHMB and BKC formulations respectively. No differences were observed between the test and reference groups for change in IOP from baseline.Conclusions: PHMB preserved brimonidine tartrate 0.15% w/v and timolol maleate 0.5% w/v ophthalmic solution was comparable to BKC preserved solution in normotensive NZW rabbits.

Aniridia with lenticular and choroidal coloboma

2019 ◽  
pp. 112067211986610
Author(s):  
Dewang Angmo ◽  
Lubhavani Dewan ◽  
Aswini Behera ◽  
Meghal Gagrani
Keyword(s):  
Intraocular Pressure ◽  
Case Report ◽  
Retinal Detachment ◽  
Female Patient ◽  
Central Corneal Thickness ◽  
Corneal Thickness ◽  
Corneal Opacity ◽  
Rare Association

This case report presents a rare association of a complete aniridia with lenticular and choroidal coloboma. An 8-year-old female patient was referred to our glaucoma clinic with aniridia, nystagmus and bilateral corneal opacity with right eye being phthisical. Ultrasonography of the phthisical eye revealed the presence of an old closed funnel retinal detachment. Further examination under anaesthesia revealed lens coloboma in the inferonasal quadrant and presence of a choroidal coloboma in the left eye. The intraocular pressure was 28 mmHg with a central corneal thickness of 693 µm. A macula sparing laser barrage around the colobomatous area was done in the left eye and topical ocular hypotensives were started.

Corneal Toxicity Studies in Rabbits and Dogs with Hydroxyethyl Cellulose and Benzalkonium Chloride

1989 ◽  
Vol 13 (3) ◽  
pp. 500-508 ◽  
Author(s):  
G. DURAND-CAVAGNA ◽  
P. DELORT ◽  
P. DUPRAT ◽  
Y. BAILLY ◽  
B. PLAZONNET ◽  
...  
Keyword(s):  
Benzalkonium Chloride ◽  
Hydroxyethyl Cellulose ◽  
Toxicity Studies ◽  
Corneal Toxicity

Carbachol HCl-Induced Opacity of Porcine Isolated Cornea

1989 ◽  
Vol 16 (4) ◽  
pp. 322-330
Author(s):  
Haruyoshi Igarashi ◽  
Yasumaja Katsuta ◽  
Hidefumi Matsuno ◽  
Yoshiharu Nakazato ◽  
Tohru Kawasaki
Keyword(s):  
Topical Application ◽  
Benzalkonium Chloride ◽  
Corneal Opacity ◽  
Wetting Agent ◽  
Great Care ◽  
Epithelial Surface ◽  
In Vitro Development ◽  
Endothelial Surface ◽  
Vitro Development

The in vitro development of porcine corneal opacity induced by carbachol was monitored using a simple, specially constructed opacitometer. Corneas were used intact, without epithelium, or without endothelium, or stroma only. Solutions of carbachol were applied to both surfaces, to the epithelial surface only or to the endothelial surface only. When carbachol was applied either to both surfaces or to the epithelial surface only, there was a significant increase in opacity compared with controls in the order: both epithelium and endothelium removed>epithelium removed>endothelium removed>intact. However, when applied to the endothelial surface only of intact and endothelium-removed corneas, carbachol caused an opacity comparable to control values. This confirms that the drug is safe for use as a topical application in the eye. However, the opacity which develops in corneas in response to benzalkonium chloride indicates that great care must be taken in determining the optimal concentration to use as a “wetting agent”.

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