Dentist Visual Task Analysis

Question 1

Adaptation Effects - light/dark/glare - for Dentist?

Answer 1

• Effects of dark adaptation are not significant
  o Dentist works in v well-lit conditions & indoors in well-lit office/consulting room
• Light adaptation is important
  o Subjects who have poor light adaptation will operate inefficiently in this environment
• Glare can cause ↓ efficiency
  o Inappropriate light shed on mouth of px

Question 2

Time taken to respond to particular stimulus for a dentist?

Answer 2

• Dentist operating at v. close distances
  o MUST have good near vision
• In a static environment
• Therefore, space scotoma does not exist  so responding quickly to task

Question 3

Flicker (strobe effect) for dentist?

Answer 3

• Tools rotate at v high speeds & stroboscopic effects are likely to be slight
• Dentist is aware of position of drill bit, despite it blurring w/ fast rotation
  o No flicker or light effect perceived as moving too quickly

Question 4

Postition in VF/VF size for dentist?

Answer 4

• Work exclusively in foveal vision
• Dentist is normally working inside px’s mouth but may locate other pieces of equipment
• Good oculomotor control & good accommodation is required

Question 5

Viewing Distance (Accommodation) for Dentist?

Answer 5

• Dentist works predominantly w/ near vision
• Distance vision also required – have to go and pickup instruments
• Dentist sits behind px when operating on upper teeth:
  o Viewing distance ~30cm
  o Magnifying mirror used
• Dentist sits in front of px & slightly to one side when operating on lower teeth:
  o Viewing distance ~40cm
• Dentist may require a near addition if presbyopic to provide necessary range of vision

Question 6

Viewing distance (convergence) for Dentist?

Answer 6

• V important
• Dentists examine X-rays, which are normally examined at or just below eye level
• X-ray photographs could be clipped onto operating lamp – superior field of view used
• Due to large amount of time spent w/ near vision, a large bifocal or trifocal segment may be required – should be wide & set quire high
  o Regardless of if presbyopic or not
• If dentist suspends X-ray photographs from operating lamp, an intermediate near add in upper part of lens may be of use
• Due to v close working distance for top teeth, good convergence amplitude is required

Question 7

Visual subtense of task detail (size/acuity) for dentist?

Answer 7

• Dentist must have good acuity to see fine details of teeth, & good visuomotor control to use small instruments in a v small space

Question 8

Motion of Task for Dentist?

Answer 8

• Little or no motion involved in task dentist is performing
  o Unless px moves but shouldn’t for their own safety!

Question 9

Contrast of task detail for Dentist?

Answer 9

• Contrast may be low especially when looking for subtle changes in tooth or gum colour
• High level of illumination inside mouth is required
• Operating lamp provides this illumination whilst being designed to minimise direct glare

Question 10

Colour of Task for Dentist?

Answer 10

• Colour matching abilities of dentist are v important for selecting correct formulation of material to match filling/crown to natural colour of px’s teeth
• Illumination from operating lamp should have high colour rendering index
• Background on which colours are put affects colour perception
• Many dentists use a filling material which is hardened using UV light
  o This light is generated from an intensely blue source – if viewed directly can cause distortions in dentist’s colour perception for subsequent pxs
  o Dentist puts blue light through yellow filter

Question 11

Clarity of task detail for dentist?

Answer 11

• Task detail should be sharp
• Clarity of task detail can be impaired during drilling by fine mist of water vapour & fragments of material that are produced from teeth
  o Always have dental nurse sucking up debris & water etc

Question 12

Stereopsis requirements for dentist?

Answer 12

• V important for dentist who is operating on small objects in 3D & in a restricted space
• Excellent oculo-motor control is needed

Question 13

VF requirements for dentist?

Answer 13

• Area dentist normally work is restricted
• Therefore, no special requirements for extensive VF
• Really only foveal area needed

Question 14

Hazards for dentist?

Answer 14

• Flying particles are produced during drilling & buffing of teeth
• Such particles may contain bacteria which could cauase infection
• Ocular protection (plastic safety lenses/goggle/shield) is advisable
• No particular chemical hazard
• UV light used to harden fillings is a potential radiation
• Harmful effects of radiation can be cumulative
  o Should use yellow shields, plastic safety lenses or goggles to absorb UV light
• Currently 4 areas of dental care using laser technology:
  o Cavity removal
  o Whitening teeth
  o Curing/hardening bonding material
  o Periodontal care

Question 15

Training Requirements for dentist?

Answer 15

• Training of dentist is v extensive & must help in performance of their visual tasks
• Must have good vision