Table of Contents - WOC 2012

FP-REF-TH 49 (9)
Intraoperative Predictability of Femtosecond Laser Created Flap
Thickness, Using the Hand Held Bioptigen OCT
Malhotra Chintan (1) , Shetty Rohit (1) , Veluri Bindu (1) , Shetty Bhujang (1)
1. Narayana Nethralaya
To compare the intended and achieved thickness of flaps created by the FS200
Wavelight› femtosecond laser in LASIK patients , using the Bioptigen spectral
domain OCT.
Methods: Femtosecond laser (FS 200 Wavelight) was used to create 100
micron thick flaps in 40eyes of 20 patients undergoing LASIK. The hand held
Bioptigen spectral domain OCT was then used to measure the flap thickness
prior to lifting the flap for laser ablation. Flap thickness was measured 1.5 mm
and 3.5 mm on either side of the centre of the cornea.
Results: In all 40 eyes flap thickness at the 1.5 mm zone was within ±7 microns
of the intended thickness (mean 97microns, range 93-105 microns) while at
3.5 mm zone it was within ±12 microns (mean 104, range 94 -112 microns) of
intended thickness.
Conclusion: The FS 200 Wavelight femtosecond laser is consistently and
precisely able to achieve flaps of uniform thickness from the centre to the
periphery as measured intraoperatively.
FP-REF-TH 49 (10)
Optical Quality Analysis One Month After FS200 Femtosecond Laser
for Myopia
Dhawan Shikha (1) , Shetty Rohit (2) , K. Shetty Bhujang (2) , Harsha Shri (2)
1. Aditya Jyot Eye Hospital
2. Narayana Netralaya
Purpose: To analyse the optical quality of eye one month after FS200
femtosecond laser to correct myopia.
Methods: In this prospective observational, comparative study the retinal
image quality of 51 patients was analysed before and after undergoing
FS200 femtosecond laser. Mean age was 25.31 ±4.15 years and the mean
spherical equivalent was 4.6 ±2.1D (range 1.5-9.0). The eye›s optical quality
was measured using the Optical Quality Analysis System (OQAS), which is
an instrument based on the double-pass technique. The following parameters
were analysed: the modulation transfer function cutoff frequency (MTFcutoff),
the Strehl ratio, the objective scatter index (OSI) and the OQAS values
(OV100%, OV20%, OV9%). Measurements were performed before surgery
and 1 day and 1 month after surgery.
Results: The mean MTF value preoperatively was 36.24 ±9.17 which decreased
to 31.82 9.26 at first postoperative day but improved to 34.65 ±9.1 one month
after surgery. The mean values of OSI pre-operatively, at first post-operative
day and 1 month after surgery were 0.749 ±0.314, 1.023 ±0.308 and 0.907
±0.297 respectively. The Strehl ratio and the OQAS values also followed a
similar trend.
Conclusion: The optical quality parameters showed a decrease (75% of their
initial values) 1 day postoperatively but regained 92% of their values after 1
month.
WOC2012 Abstract Book
FP-REF-TH 49 (11)
To Compare Treatments with Wavefront Optimized and Custom Q
Ablations
Rao Anupama (1) , Warhekar Pramod
1. The City Hospital
Purpose: To compare the results of the Q-factor customized aspheric ablation
profile with the wavefront optimized ablation profile for the correction of myopic
astigmatism.
Methods: A retrospective study of patients treated for myopia and astigmatism
at The City Hospital Dubai, between May 2007 and May 2008 was done.
One group consisted of 86 eyes of 46 patients who underwent Intralasik with
wavefront optimized ablations. The other group comprised of 119 eyes of 63
pts who underwent custom Q treatment. Laser treatment in all cases was
accomplished with the Wavelight Eye-Q 400 Hz excimer laser.Preoperative
and 3-month postoperative Q-values and corneal spherical aberrations were
analyzed.
Results: In the wavefront optimized group, mean Q-value changed from 0.29
+/- 0.132 preoperatively to 0.35 +/- 0.389 postoperatively. In the custom Q
group, mean Q-value changed from -0.29 +/- 0.120 preoperatively to 0.29 +/-
0.398 postoperatively. No statistically significant difference (P= 0.15) between
the two groups was noted. Similarly, there was no statistically significant
difference (P= 0.149) in the mean corneal spherical aberrations between the
groups.
Conclusions: With regard to safety and refractive efficacy, custom-Q ablation
profiles were clinically equivalent to wavefront optimized profiles in corrections
of myopia and astigmatism.
Free Paper: Retina - Medical
Thu 16 Feb 16:30 - 18:00 Conference Room A4
FP-RET-TH 50 (1)
Pilot Randomized Clinical Trial of Optos-guided Pascal Targeted
Retinal versus Variable Fluence PANretinal (PETER PAN)
20-millisecond Laser in Diabetic Retinopathy
Stanga Paulo (1) , Muqit Mahiul (1) , Stefansson Einar (3) , Henson David (1) , Marcellino
George (2)
1. Manchester Royal Eye Hospital
2. Optimedica Coporation
3. National Hospital Reykjavik
Objective: We investigated 2 novel laser techniques, Pascal targeted retinal
laser photocoagulation (TRP) and reduced fluence/minimally-traumatic
panretinal laser (MT-PRP),compared to standard-intensity PRP (SI-PRP).The
main aim was to the efficacy and safety profile of the 3 techniques in treatmentnaive
proliferative diabetic retinopathy (PDR).
Methods: Three-arm randomized clinical trial (10 eyes/ arm). PDR was treated
with single-session 2,500 burns. ETDRS visual acuity (VA),central retinal
thickness (CRT),24-2 SITA-Std visual fields (VF),multispectral imaging
(MSI),and Oxymap oximetry were recorded at baseline, 4 and 12-weeks postlaser.
Masked graders analyzed pair-wise changes in each parameter over
time (TRP vs. SI-PRP;MT-PRP vs. SI-PRP).
Results: Clinical and safety results reported for 29 eyes (16 males, 7 female)
with moderate PDR grade. Laser fluence was significantly lower in TRP (4J/
cm2) and MT-PRP (2.7J/cm2) compared to SI-PRP (4.8J/cm2,p