scholarly journals Benzalkonium chloride corneal toxicity post-cataract surgery

2020 ◽  
Vol 17 (1) ◽  
pp. 56-60
Author(s):  
Keith Ong ◽  
Leonard Ong

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.

1993 ◽  
Vol 21 (3) ◽  
pp. 372-383
Author(s):  
Haruyoshi Igarashi ◽  
Yasunaga Katsuta ◽  
Kayoko Sawa ◽  
Yuu Chiba ◽  
Michio Kozima ◽  
...  

The incubation of isolated porcine corneas (intact, with the epithelium or endothelium plus Descemet's membrane removed, or with both the epithelium and endothelium plus Descemet's membrane removed) with solutions of pilocarpine HCl (5 X 10 4M or 5 x 10-3M) for four hours caused very little increase in opacity when compared with corneas incubated with physiological saline. However, at a higher concentration (5 x 10-2M), the application of pilocarpine to the endothelial surface, or to both the epithelial and endothelial surfaces of intact corneas, caused an obvious increase in opacity. The addition of the preservative benzalkonium chloride (BC; 0.005%) to pilocarpine solutions caused an increase in opacity, but in no circumstances did this appear to be other than an additive effect, since incubation with BC alone had an opacifying effect. This in vitro test confirms that pilocarpine is a safe drug for application as eye-drops. Studies using high performance liquid chromatography showed that BC increased the amount of pilocarpine passing through the cornea from the epithelial to the endothelial surface. A small amount of BC also passed through the cornea over the 4-hour experimental period.


Author(s):  
A. Prasanth Babu ◽  
P. Jagapathi Ramayya ◽  
Y. Nagamalleswari ◽  
Makkena Sreenu ◽  
K. Lakshmi Kavitha

Background: Affections of eye commonly encountered in all the species of animals. If these not treated in time, the vision may be hampered, this may impair the physical ability, utility and productivity of animals leading to economic loss to the animal owners. Corneal dystrophies like basement membrane dystrophy, stromal dystrophy, endothelial dystrophy, corneal erosions and corneal ulcerations etc., seen in the aged buffaloes. The current study was carried out to establish basic data and to provide authentic information to the clinicians on ageing changes in eyes of buffaloes.Methods: The study on age related changes in the cornea was conducted on 63 eye balls of locally available buffaloes of different breeds in and around Proddatur. These buffaloes were categorized into 3 groups based on their age i.e., group I (1-5 yrs), group II (6-10 yrs) and group III (11 yrs and above) buffaloes. The eyeballs were isolated and fixed with Davidson’s fluid. The paraffin sections of cornea were subjected for routine histological study.Result: The mean total thickness (µm) of cornea was increased from group I to III animals and it was 747.22±13.57, 853.33±11.05 and 897.22±8.06. Hence, The mean thickness (µm) of all five layers of cornea increased with advancement of age. Superficial corneal epithelial layer was made up of non keratinized stratified squamous epithelium with 6 to 7 layers at early age and 12-14 layers of cells in adult animals. The mean thickness (µm) of corneal epithelium in group I to III animals was 117.04±3.37, 122.59±2.23 and 133.71±3.55 respectively. Bowman’s membrane of cornea was measured 12.97±0.86, 17.22±0.55 and 18.71±0.68 in group I, II and III animals respectively. The mean thickness (µm) of corneal stroma in group I to III animals was 600.75±10.33, 672.22±10.46 and 690.00±5.32 respectively. This was mainly due to progressive increase in number of collagenous lamellae. The keratocytes became thin in old animals. Thickness of posterior band zone (PBZ) of Descemet’s membrane was increased with advancement of age. The mean thickness (µm) of Descemet’s membrane and endothelium together was in group I, II and III animals was 16.48±0.91, 41.29±2.25 and 54.82±1.44 respectively. The corneal endothelial cells were enlarged and increased in size in old buffaloes. The age related pigmentation was also noticed in epithelium and stroma of cornea in animals of group III. Density of sub basal nerve plexuses between the stroma and the corneal epithelium was not altered with advancement of age.


Author(s):  
Malik Y. Kahook

Corneal injury resulting from glaucoma surgery has been well described. Causes of injury can range from direct mechanical manipulation to the often more subtle pharmacologically induced injuries that occur with use of antifibrotic medications. Descemet’s membrane detachment (DMD) occurs uncommonly during or after intraocular surgery and has been linked with a variety of procedures ranging from simple clear cornea cataract extraction to deep lamellar keratoplasty. The corneal endothelium, which rests upon Descemet’s membrane, functions as a pump to keep the stroma from becoming swollen. Therefore, DMD results in focal corneal edema and possibly bullous keratopathy. If detachment of Descemet’s membrane extends far enough centrally, visual acuity may become sufficiently compromised to necessitate corneal transplantation surgery (either full-thickness penetrating keratoplasty [PKP] or Descemet’s stripping with automated endothelial keratoplasty [DSAEK]). In glaucoma surgery, DMD often results from the mechanical manipulation that occurs with creation of the cornealtrabecular meshwork opening. Knowing how to accurately diagnose and treat DMD can prevent disastrous consequences and preserve vision. Mackool and Holtz proposed separating DMD into 2 categories, planar and nonplanar, depending on the distance of separation between Descemet’s membrane and the posterior corneal stroma. Planar DMD involves less than 1 mm separation of Descemet’s membrane from the corneal stroma and may be limited to the periphery or extend from the periphery to central regions. Nonplanar DMD involves greater than 1 mm separation of Descemet’s membrane from the corneal stroma and may also be categorized as limited to the periphery or extending to central regions. The significance of this classification was the belief that planar DMD was more likely to spontaneously resolve while nonplanar DMD required surgical intervention. Assia and colleagues also split DMD into 2 categories: DMD with scrolling of tissue and DMD without scrolling of tissue. They believed this classification more accurately described potential for spontaneous resolution in that nonscrolled DMD was more likely to resolve without surgical intervention, even if its location was >1mm from the posterior corneal stroma. While useful as a general guide, these classification systems are not foolproof, and each case of DMD should be viewed independently.


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