Table 1.

Single channelled scopes

Ref.	Year	Projection system for 3D	Who and what assessed	Objective outcomes	Subjective outcomes
McDougall et al[6]	1996	Active shuttering screen and glasses	22 urological and gynaecological surgeons, non-novice Pig-lab, laparoscopic vessel dissection and securing, suturing and knot tying	Time for completion. No significant difference found	3D not felt to enhance image quality or enhance performance. Blurred vision and eye fatigue with 3D
Dion et al[7]	1997	Active shuttering screen and glasses	Surgeons and non-surgeons. Lab visual (n = 8) and motor skills (n = 9)	Time and errors. Improvement in both with 3D	Glasses bothersome and dizziness reported
Chan et al[8]	1997	Active shuttering screen and glasses	32 surgeons, 11 with and 21 without laparoscopic experience 1 × lab based skills task	Time for completion in 2D and 3D (1 repetition). No significant difference	50% felt no improved performance although 66% felt depth perception improved 40% felt reduced image quality and dimmer; 10% reported dizziness and eyestrain
Hanna et al[9]	1998	Active shuttering screen and glasses (A/S)	4 surgical SpRs performing 60 laparoscopic cholecystectomies	Time for completion and errors No significant difference	Visual strain, headache and facial discomfort with 3D system
Mueller et al[10]	1999	Active shuttering screen and glasses	30 subjects (10 with and 20 without laparoscopic experience) 4 × lab based skills tasks for all, then experienced did suturing tasks	Time for attempts, and success/failure of attempt No significant difference	Reported loss of concentration, headaches and distraction with 3D system
Herron et al[11]	1999	3D (active shuttering screen and glasses) and 3D HMD	50 laparoscopic novices 3 × lab based skills tasks	Time to completion of 3 skills tasks in each visual system (2 × repitions) No significant difference	Although 48% preferred 3D A/S screen over all, 7% and 25% respectively reported headaches with 3D screen and 3D HMD. 82% found HMD uncomfortable
Mueller-Richter et al[12]	2003	3D (active shuttering screen and polarising glasses) and 3D Autostereoscopic screen	59 laparoscopic novices 3 × lab based skills tasks	Number of completions in time limit and subjective difficulty No significant difference	Flickering reported with both 3D systems
Bhayani et al[13]	2005	HMD	24 surgical residents, minimal laparoscopic experience. 1 × lab based skills task	Time for completion in 2D and 3D (1 repetition) Significant reduction in time	> 50% preferred the 3D system and found task easier in 3D No subjective assessment on physical symptoms
Patel et al[14]	2007	HMD	15 novices and 2 experts 5 × lab based skills tasks	Time and accuracy in 2D and 3D (1 repetition) of the novices compared to the experts Significant difference in both for novices only in 3D	NA
Bittner et al[15]	2008	HMD	2 novices, 2 intermediate and 2 experts 2 × lab based suturing tasks (based on handedness, visual system and articulating needle holder)	Time and accuracy in 2D and 3D (multi repetitions with each variable) No significant difference	83% felt improved depth perception. No reported physical symptoms
Votanopoulos et al[16]	2008	HMD	36 surgical residents and medical students (11 with and 25 without laparoscopic experience) 6 × lab based skills tasks (rpt 3/12 later)	Time and errors in 2D and 3D (1 repetition) Significant improvement in time and errors in novice group only	NA
Kong et al[17]	2009	Passive polarising screen and glasses	21 novices and 6 experienced surgeons 2 × lab based skills tasks	Time and errors in 2D and 3D (4 repetitions of each over 4 d) Significant reduction in errors in 3D novices, no other significant difference noted	Dizziness and eye fatigue in novice with 3D system which improved with time
Mistry et al[18]	2013	Passive polarising screen and glasses	31 medical students (novices) 4 × lab based skills tasks (MISTELS)	Task Performance in 2D and 3D as per MISTELS scoring system No significant difference	No detrimental symptoms with 3D

NA: Not available; 3D: Three-dimensional; 2D: Two-dimensional; HMD: Head mounted display.