Quantitative thermographic analysis of viscoelastic substances in an experimental study in rabbits.
OBJECTIVE
To measure the temperature parameters on the corneal surface during the delivery of standardized ultrasound energy assisted with ophthalmic viscosurgical devices (OVDs) or different temperatures of irrigating solutions in an experimental animal model.


METHODS
Department of Ophthalmology and Visual Rehabilitation, Medical University of Lodz, and Central Institute for Labor Protection, National Research Institute, Warsaw, Poland.


METHODS
Thirty rabbits (60 eyes) were randomly divided into 6 groups in which different OVD or balanced salt solutions (BSS) were used: group 1: Viscoat (sodium hyaluronate 3%-chondroitin sulfate); group 2: Provisc (sodium hyaluronate 1%); group 3: soft-shell technique; group 4: Celoftal (hydroxypropyl methylcellulose 2%); group 5: BSS 22 degrees C; and group 6: BSS 4 degrees C. After the nucleus and lens cortex were removed, the anterior chamber was filled with OVD or BSS and a phaco tip was introduced into the pupillary plane and switched on. The same phaco tip parameters were used in all groups. For thermographic measurements (ie, maximal temperature [MT], dynamic rise in temperature [DRT], and time when the maximal level of temperature [TMLT] was achieved), a thermocamera was used.


RESULTS
Mean preoperative temperature on the rabbit corneal surface was 22.76 degrees C +/- 1.48 degrees C (SD). Working with a phaco tip increased the temperature in each group. A significantly higher MT was observed in group 5 (27.85 degrees C +/- 0.52 degrees C), followed by group 2 (27.75 degrees C +/- 0.54 degrees C), group 3 (27.74 degrees C +/- 0.46 degrees C), and group 4 (27.25 degrees C +/- 0.60 degrees C), than in group 6 (26.81 degrees C +/- 0.34 degrees C) and group 1 (26.52 degrees C +/- 0.48 degrees C) (P<.05). Significantly higher values of DRT and shorter TMLT values were observed in group 5 (1.16 degrees C/s +/- 0.42 degrees C/s, 4 seconds) and group 6 (0.91 degrees C/s +/- 0.13 degrees C/s, 5 seconds) than in groups 2, 3, 1, and 4 (0.09 degrees C/s +/- 0.07 degrees C/s, 30 seconds; 0.08 degrees C/s +/- 0.04 degrees C/s, 40 seconds; 0.07 degrees C/s +/- 0.03 degrees C/s, 45 seconds; 0.06 degrees C/s +/- 0.02 degrees C/s, 50 seconds, respectively) (P<.0001).


CONCLUSIONS
Currently used OVDs potentially offer different levels of protection against the increase in temperature that occurs during phacoemulsification. Therefore, the surgeon should consider this aspect when choosing an OVD, particularly in difficult cases (ie, hard nucleus, shallow anterior chamber, endothelial abnormalities).
Jurowski
Piotr
P
Department of Ophthalmology and Visual Rehabilitation, Medical University of Lodz, Poland. p.jurowski@poczta.wprost.pl
Goś
Roman
R
Kuśmierczyk
Jarosław
J
Owczarek
Grzegorz
G
Gralewicz
Grzegorz
G
D000818:Animals; D001831:Body Temperature / Q000502:physiology*; D019923:Capsulorhexis; D002809:Chondroitin Sulfates; D003315:Cornea / Q000502:physiology*; D004338:Drug Combinations; D005126:Eye Burns / Q000517:prevention & control; D006820:Hyaluronic Acid; D065347:Hypromellose Derivatives; D007431:Intraoperative Complications / Q000517:prevention & control; D008747:Methylcellulose / Q000031:analogs & derivatives*; D018918:Phacoemulsification / Q000009:adverse effects / Q000379:methods*; D011817:Rabbits; D013817:Thermography / Q000379:methods
D004338:Drug Combinations; D065347:Hypromellose Derivatives; D006820:Hyaluronic Acid; D008747:Methylcellulose; D002809:Chondroitin Sulfates