Effect of different irrigating solutions on aqueous humour pH changes, intraocular pressure and histological findings after induced alkali burns.
OBJECTIVE
To evaluate the effects of hypo-osmolar tap water and isotonic saline solution on the intracameral pH, intraocular pressure and histological changes in alkali burned rabbit eyes.


METHODS
Four groups of four rabbit corneas each were burned with 2 N sodium hydroxide, and then rinsed with 0.5 l or 1.5 l of saline solution or tap water, respectively. Changes in pH were monitored with an intracameral microelectrode. Intraocular pressure (IOP) was monitored by a transducer placed in the vitreous cavity. After enucleation, histology was performed.


RESULTS
The pH increased after 1.5 min following alkali application. Irrigation with different solutions affected the maximum pH levels reached. Following the tap water rinse, the maximum rise was significantly lower than after the saline solution rinse. The maximum rise following rinsing with 1.5 l of tap water showed a significant delay. The increase in IOP was 23 +/- 10 mmHg without differences between the groups; the original pressure was recovered after 18 +/- 9 min. Histology of the eyes revealed a significant oedema in all corneas. Other ocular structures appeared unchanged.


CONCLUSIONS
The hypo-osmolarity of tap water led to remarkable corneal oedema. Enlargement of the diffusion barrier and intracorneal dilution inhibit elevated intracameral pH levels. The difference in maximum pH levels reached may influence the degree of subsequent intraocular structure injury. Therefore, the use of iso-osmolar saline solution proves to be less efficacious than tap water as an irrigation agent for ocular burns.
Kompa
Sirpa
S
University Eye Clinic, University Hospital Aachen, Aachen, Germany. skompa@gmx.de
Redbrake
Claudia
C
Hilgers
Christoph
C
Wüstemeyer
Henrike
H
Schrage
Norbert
N
Remky
Andreas
A
D000818:Animals; D001082:Aqueous Humor / Q000187:drug effects*; D002057:Burns, Chemical / Q000188:drug therapy* / Q000473:pathology; D003315:Cornea / Q000187:drug effects; D015715:Corneal Edema / Q000473:pathology*; D004195:Disease Models, Animal; D004567:Electrodes, Implanted; D005126:Eye Burns / Q000139:chemically induced* / Q000473:pathology; D005260:Female; D006863:Hydrogen-Ion Concentration; D007429:Intraocular Pressure / Q000187:drug effects*; D007552:Isotonic Solutions; D008839:Microelectrodes; D009883:Ophthalmic Solutions / Q000494:pharmacology*; D009994:Osmolar Concentration; D011817:Rabbits; D012965:Sodium Chloride / Q000494:pharmacology; D012972:Sodium Hydroxide / Q000633:toxicity; D007507:Therapeutic Irrigation; D014867:Water / Q000494:pharmacology
D007552:Isotonic Solutions; D009883:Ophthalmic Solutions; D014867:Water; D012965:Sodium Chloride; D012972:Sodium Hydroxide