Anterior chamber depth estimation by Scheimpflug photography.
OBJECTIVE
To obtain a model suitable for evaluation of the anterior chamber depth (ACD) maintaining capacity of viscoelastic substances--a critical parameter in cataract surgery.


METHODS
ACD was estimated using an anterior segment analysis system (EAS-1000, Nidek Co Ltd, Japan). Variation was studied as an effect of batch number and eye within batch, storage, globe fixation, globe position, and repeated analyses of Scheimpflug images.


RESULTS
Considerable variation in ACD was found between eyes, batches, and as a result of prolonged storage (biological factors). Different IOPs before surgery caused significant alterations in ACD after overfilling with a viscoelastic substance. No significant differences were found when the globe position was altered or when the ACD was re-estimated repeatedly from the same photograph.


CONCLUSIONS
Differences due to biological factors are more important than methodological errors caused by the Scheimpflug instrument. To reduce these variations when viscoelastics are evaluated, all measurements should be calculated as % of ACD before surgery and the anterior chamber should be overfilled with a viscoelastic solution.
Holmén
J B
JB
Unit of Ophthalmology, Faculty of Veterinary Medicine, Swedish University of Agricultural Sciences, P.O. Box 7018, SE-750 07 Uppsala, Sweden. jorgen.holmen@kirmed.slu.se
Ekesten
B
B
Lundgren
B
B
D000818:Animals; D000867:Anterior Chamber / Q000033:anatomy & histology*; D002387:Cataract Extraction; D003951:Diagnostic Errors; D003941:Diagnostic Techniques, Ophthalmological; D006820:Hyaluronic Acid / Q000008:administration & dosage; D007429:Intraocular Pressure; D023421:Models, Animal; D010781:Photography / Q000379:methods*; D011897:Random Allocation; D013552:Swine
D006820:Hyaluronic Acid