[Comparison between Lenstar LS 900 non-contact biometry and OcuScan RXP contact biometry for task delegation].
BACKGROUND
Non-contact biometers have many advantages including the delegation of tasks to orthoptists. This study analyses the reliability of measurements comparing contact and non-contacts techniques.


METHODS
Comparative measurements were taken on 86 eyes of 45 patients (mean age: 74 years; 44.4 % males) in preoperative phacoemulsification by three orthoptists with experience in this task. Each patient had non-contact measurements (Lenstar LS 900, Haag-Streit) and contact measurements (corneal biometry and ultrasound pachymetry with OcuScan RXP, Alcon) and a keratometry refractometer (TONOREF II, Nidek). The axial length data, pachymetry, power of the intraocular lens (SRK/T formula), anterior chamber depth, and the average keratometry were analyzed by paired comparisons.


RESULTS
The non-contact biometer was ineffective in 5.8 % of cases (Parkinson's disease, two cases; dense posterior subcapsular cataracts, three cases). The non-contact pachymetry was statistically significantly higher (546.4 μm vs. 538.6 μm; p<0.001). The axial length was significantly longer for the non-contact measurement (23.21 mm vs. 23.05 mm; p<0.0001). In 25.9 % of patients, this difference was greater than or equal to 0.3mm and affected the power of the implant chosen. The anterior chamber depth measured on non-contact biometry was statistically greater (3.33 mm vs. 3.03 mm; p<0.0001). However, there was no significant difference regarding the average keratometry (43.82 D vs. 43.78 D; p=0327).


CONCLUSIONS
Besides the infectious benefit for patients, absence of cleaning and decontamination of biometric probes, non-contact measurements using Lenstar are an example of a safe activity that can be delegated to assistants. This technique has been used to optimize the refractive outcome of 25.9 % of our patients undergoing refractive cataract surgery.
Service d'ophtalmologie, hôpital d'instruction des armées Desgenettes, 108, boulevard Pinel, 69003 Lyon, France. elchehab_hussam@hotmail.fr
H
H
El Chehab
J-M
JM
Giraud
A
A
Le Corre
N
N
Chave
F
F
Durand
S
S
Kuter
G
G
Ract-Madoux
B
B
Swalduz
G
G
Mourgues
C
C
Dot
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000488:Allied Health Personnel; D000867:Anterior Chamber / Q000000981:diagnostic imaging / Q000648:ultrastructure*; D001699:Biometry / Q000295:instrumentation* / Q000379:methods; D002386:Cataract / Q000150:complications / Q000000981:diagnostic imaging / Q000473:pathology*; D003315:Cornea / Q000000981:diagnostic imaging / Q000648:ultrastructure*; D003941:Diagnostic Techniques, Ophthalmological / Q000295:instrumentation*; D004867:Equipment Design; D015817:Eye Infections / Q000517:prevention & control; D005260:Female; D006801:Humans; D007368:Interferometry / Q000295:instrumentation*; D007908:Lens, Crystalline / Q000000981:diagnostic imaging / Q000648:ultrastructure*; D007910:Lenses, Intraocular; D008297:Male; D008875:Middle Aged; D009988:Orthoptics; D010300:Parkinson Disease / Q000150:complications; D032024:Personnel Delegation; D018918:Phacoemulsification; D011300:Preoperative Care; D011446:Prospective Studies; D012031:Refractometry / Q000295:instrumentation* / Q000379:methods; D014463:Ultrasonography