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Standardization of laser in situ keratomileusis surgical technique evaluated by comparison of procedure time between 2 experienced surgeons

Reinstein, Dan Z. MD, MA(Cantab), FRCSC, FRCOphth*; Carp, Glenn I. MB BCh, FC Ophth (SA); de Benedictis, Daria MD; Archer, Timothy J. MA(Oxon), DipCompSci(Cantab); Gobbe, Marine PhD, MSTOptom; Khan, Raynan BSc; von Borch, Max

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Journal of Cataract & Refractive Surgery: May 2015 - Volume 41 - Issue 5 - p 1004-1008
doi: 10.1016/j.jcrs.2014.08.039
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Laser in situ keratomileusis (LASIK) is one of the most frequently performed elective ophthalmic surgical procedures, and intraoperative surgical technique is an important component of optimizing efficacy and safety. In a multisurgeon clinical setting, it is clearly preferable for surgeons to produce optimized equivalent results, delivering a similar standard of care to any patient. It has been shown that experience accumulated by surgeons as a group significantly improves outcomes compared with an individual surgeon.1 One of the authors (D.Z.R.) previously developed a standardized surgical treatment protocol between 1998 and 2001 within a high-volume corporate practice.2 This surgical treatment protocol was refined and adopted as the recommended surgical treatment protocol for use with the MEL 803 excimer laser (Carl Zeiss Meditec AG) in 2003 and modified for incorporation of the Visumax4–7 femtosecond laser (Carl Zeiss Meditec AG) in 2007. Between 2005 and 2007, another author (G.I.C.) underwent refractive surgical fellowship training under D.Z.R. with specific focus on the recommended LASIK surgical treatment protocol. This training proved to be successful in showing that the visual outcomes were identical between the 2 surgeons for their first 200 consecutive LASIK procedures using the Visumax femtosecond laser.8

The present study evaluated the level of standardization in surgical technique by comparing the application of this recommended LASIK surgical treatment protocol between 2 surgeons previously shown to produce equivalent visual outcomes,8 each with 5 years’ experience using the femtosecond and excimer lasers, through stepwise evaluation of surgical videos and statistical analysis.

Materials and methods

This was a retrospective comparative case series of consecutive bilateral simultaneous LASIK procedures for each of 2 experienced LASIK surgeons (D.Z.R., G.I.C.) using the Visumax femtosecond laser and MEL 80 excimer laser at the London Vision Clinic, London, United Kingdom. Patients provided informed consent and permission to use their data for retrospective analysis and publication.

Both surgeons had specialist training and extensive experience with the recommended surgical treatment protocol for the Visumax and MEL 80 lasers, which includes 63 steps. (The recommended surgical treatment protocol can be reviewed online.A) The surgical technique and details have been described.8 Video 1 (available at shows a real-time video of a bilateral LASIK procedure following this recommended surgical treatment protocol. Video 2 (available at shows a side-by-side comparison of the 2 surgeons performing the excimer laser portion of the procedure (eye tracker, flap lift, ablation, and flap replacement). Before the start of this study, each surgeon had performed more than 3500 LASIK procedures using the 2 lasers.

All procedures were recorded intraoperatively, including the video feed from the microscope camera as well as from an external camera mounted on the laser to capture the surgeon’s hand movements, as per the clinic’s standard protocol. The videos were reviewed, and intraoperative timestamps were recorded for each step during the procedure. The total surgery time was defined as the time from speculum insertion in the first eye to removal from the second eye after excimer laser ablation.

Excel 2010 software (Microsoft Corp.) was used for data entry and statistical analysis.


Table 1 shows descriptive statistics for the eyes treated by each surgeon including age, sex, date range, attempted spherical equivalent refraction, and attempted cylinder correction.

Table 1
Table 1:
Demographic data for the populations by surgeon.

Table 2 shows the mean, standard deviation (SD), range, and 90th percentile for the time taken to perform each individual step for both surgeons as well as the difference between them. Excluding the difference required for ablation time resulting from the difference in refraction treated, the difference between surgeons in time taken for each individual step was greater than 5 seconds for 5 steps and less than 5 seconds for all the other 27 steps. Surgeon D.Z.R. took on average 15 seconds (12%) longer than G.I.C. for 1 step (moving the patient between lasers and calibrating the excimer laser). This difference was accounted for by the unpredictable variation in how much time was needed to calibrate the excimer laser to the satisfaction of the surgeon. Surgeon G.I.C. took longer than D.Z.R. for 4 steps as follows: (1) inserting the speculum into the first eye at the beginning of the procedure (13 seconds [93% longer]), (2) preparing the second eye for flap creation (18 seconds [45% longer]), (3) marking the flap and applying the drops before excimer laser ablation of the first eye (12 seconds [86% longer]), and (4) marking the flap and applying the drops before excimer laser ablation of the second eye (12 seconds [86% longer]). On reviewing the audio portion of the video for the 2 surgeons, these 4 differences were explained by small differences in the amount of surgeon conversation with the patient; G.I.C. preferred to engage in longer preparatory patter. None of the differences occurred during a step involving surgical manipulations.

Table 2
Table 2:
Comparison between 2 experienced surgeons of the time (seconds, minutes, or both) taken to perform each individual step during a bilateral LASIK procedure. The difference between surgeons is calculated by subtracting the time for D.Z.R. from the time for G.I.C.
Table 2
Table 2:

For the majority of steps, the range of time taken was narrow, reflecting the high repeatability of each step. For certain steps, the maximum times were significant outliers, as shown by the narrow interval of the 90th percentile value of the timings.


The present study found very high concordance between 2 surgeons operating under a step-by-step standardized surgical protocol to perform bilateral LASIK. The only noticeable differences occurred during preparatory phases due to small stylistic differences in patter. Physical surgical phases were found on average to be very closely matched. This shows by proxy the adherence of both surgeons to the standardized surgical treatment protocol. These results are supported by the equivalent visual and refractive outcomes previously reported for the 2 surgeons operating under this surgical protocol.8 Studies9,10 have shown that newly trained surgeons can achieve results similar to those of experienced surgeons. This supports the recommendation that surgeons should undergo a fellowship training program that includes observation of an experienced surgeon followed by supervision of their initial procedures2,8,10,11 and shows the benefit of surgeons operating within a group adhering to a single protocol for quality-control purposes. Unless this is the case, it is very difficult to isolate the causes of differences in visual outcomes, something that patients would assume is minimal when attending a clinic for treatment.

In summary, we have shown the successful implementation of a standardized surgical treatment protocol between 2 surgeons as a basis for their reported equivalency in visual outcomes.

What Was Known

  • Equivalent visual and refractive LASIK outcomes can be achieved by novice and experienced surgeons with the use of a standardized surgical treatment protocol.

What This Paper Adds

  • Adherence to a standardized surgical protocol for 2 experienced LASIK surgeons enabled the previously reported equivalency in visual and refractive outcomes.


1. Contreras JM, Kim B, Tristao IM. Does doctors’ experience matter in LASIK surgeries? Health Econ. 2011;20:699-722.
2. Reinstein DZ, Threlfall WB, Cook R, Cremonesi E, Sutton HFS, Archer TJ, Gobbe M. Short term LASIK outcomes using the Technolas 217C excimer laser and Hansatome microkeratome in 46,708 eyes treated between 1998 and 2001. Br J Ophthalmol. 2012;96:1173-1179.
3. Reinstein DZ, Archer TJ, Gobbe M. LASIK for myopic astigmatism and presbyopia using non-linear aspheric micro-monovision with the Carl Zeiss Meditec MEL 80 platform. J Refract Surg. 2011;27:23-37.
4. Reinstein DZ, Archer TJ, Gobbe M, Johnson N. Accuracy and reproducibility of Artemis central flap thickness and visual outcomes of LASIK with the Carl Zeiss Meditec VisuMax femtosecond laser and MEL 80 excimer laser platforms. J Refract Surg. 2010;26:107-119.
5. Blum M, Kunert K, Gille A, Sekundo W. LASIK for myopia using the Zeiss VisuMax femtosecond laser and MEL 80 excimer laser. J Refract Surg. 2009;25:350-356.
6. Vetter JM, Holzer MP, Teping C, Weingärtner WE, Gericke A, Stoffelns B, Pfeiffer N, Sekundo W. Intraocular pressure during corneal flap preparation: comparison among four femtosecond lasers in porcine eyes. J Refract Surg. 2011;27:427-433.
7. Issa A, Al Hassany U. Femtosecond laser flap parameters and visual outcomes in laser in situ keratomileusis. J Cataract Refract Surg. 2011;37:665-674.
8. Reinstein DZ, Carp GI, Archer TJ, Gobbe M. Transitioning from mechanical microkeratome to femtosecond flap creation: visual outcomes of an experienced and a novice LASIK surgeon. J Cataract Refract Surg. 2012;38:1788-1795.
9. Yo C, Vroman C, Ma S, Chao L, McDonnell PJ. Surgical outcomes of photorefractive keratectomy and laser in situ keratomileusis by inexperienced surgeons. J Cataract Refract Surg. 2000;26:510-515.
10. Al-Swailem SA, Wagoner MD, King Khaled Eye Specialist Hospital Excimer Laser Study Group. Complications and visual outcome of LASIK performed by anterior segment fellows vs experienced faculty supervisors. Am J Ophthalmol. 2006;141:13-23.
11. Madu AA, Ali T. Resident laser refractive surgery training. Curr Opin Ophthalmol. 2010;21:265-268.

Supplementary data

Video 1 Real-time video of a bilateral LASIK procedure following the recommended surgical treatment protocol.

No Caption available.

Video 2 Side-by-side comparison of the 2 surgeons performing the excimer laser portion of the procedure (eye tracker, flap lift, ablation, and flap replacement) showing the close similarity between the surgical technique used.

No Caption available.

Other Cited Material

A. Reinstein D. London Vision Clinic. RSTP for LASIK. Available at: Accessed January 13, 2015
© 2015 by Lippincott Williams & Wilkins, Inc.