Table 1

Points allocated to each risk factor using Habib's potential difficulty score system.

Risk factor
Points allocated

Unable to lie flat (spinal deformity, asthma, heart failure)
1
Severe anxiety
1
Head tremor
1
Previous angle closure glaucoma
1
History of complication in fellow eye
1
Previous vitrectomy
1
Corneal scarring/cloudiness
1
Shallow anterior chamber
1
Poor pupillary dilation and/or posterior synechiae
1
Pseudoexfoliation
1
Phacodonesis/weak zonules
1
High myopia (axial length >27 mm)
1
High hypermetropia (axial length <20 mm)
1
Nuclear density grade 1–2
1
Nuclear density grade 3
2
Mature/brunescent/white/dense/total cataract
3

Osborne et al. BMC Ophthalmology 2006 6:38   doi:10.1186/1471-2415-6-38