The Lens Opacities Classification System II (LOCS II) is a
method of reproducibly evaluating age-related cataracts. It involves grading 4
features of the cataract by comparing
the features seen against a standard set of transparencies. It is an extension
of the LOCS I system, with an expanded number of photographic standards and the
use of color rather than black and white for the images. The LOCS II does not
use a measure of visual acuity since this is inconsistently correlated with the
degree of cataract formation and may be affected by other eye disorders.
The grading requires a slit-lamp examination.
|
Parameter
|
Features
|
Grade
|
|
nuclear color (NC)
|
The color of the posterior cortical/posterior subcapsular
reflex is:
|
|
|
|
< NI standard
|
NC0
|
|
|
similar to the NI standard
|
NC1
|
|
|
> NI standard
|
NC2
|
|
nuclear opalescence (N)
|
The average opalescence of the nucleus is:
|
|
|
|
<= that in N0
|
N0
|
|
|
> N0 but <= NI
|
NI
|
|
|
> NI but <= NII
|
NII
|
|
|
> NII but <= NIII
|
NIII
|
|
|
> NIII
|
NIV
|
|
cortical cataract (C)
|
The aggregate extent of linearly organized or clustered
opacities is:
|
|
|
|
<= that in C0
|
C0
|
|
|
> C0 but <= Ctr (trace)
|
Ctr
|
|
|
> Ctr but <= CI
|
CI
|
|
|
> CI but <= CII
|
CII
|
|
|
> CII but <= CIII
|
CIII
|
|
|
> CIII but <= CIV
|
CIV
|
|
|
> CIV
|
CV
|
|
posterior subcapsular (P)
|
The aggregate extent of the axial opacity seen in
retro-illumination is:
|
|
|
|
<= that in P0
|
P0
|
|
|
> P0 but <= PI
|
PI
|
|
|
> PI but <= PII
|
PII
|
|
|
> PII but <= PIII
|
PIII
|
|
|
> PIII
|
PIV
|
after Table I, page 995.
• Nuclear color
is graded by comparing the color of the posterior cortical/posterior
subcapsular reflex to the NI standard.
|
Nuclear Standard
|
Description
|
|
N0
|
clear nucleus
|
|
NI
|
early degree of nuclear opacification
|
|
NII
|
moderately advanced nuclear opacification
|
|
NIII
|
advanced nuclear opacification and browning
|
|
Cortical Standard
|
Description
|
|
C0
|
clear lens devoid of aggregated dots, flecks, vacuoles and
waterclefts
|
|
Ctr
|
minimal degree of cortical opacification and/or minispoke
formation
|
|
CI
|
more extensive opacification with small minispokes
|
|
CII
|
cortical spoking that obscures more than 2 full quadrants
|
|
CIII
|
opacification that obscures about 50% of the
intrapupillary zone
|
|
CIV
|
advanced opacification filling about 90% of the
intrapupillary zone
|
|
Posterior Subcapsular Standard
|
Description
|
|
P0
|
clear posterior capsule
|
|
PI
|
cataract filling about 3% of the area of the posterior
capsule
|
|
PII
|
about 30% opacification of the area of the posterior
capsule
|
|
PIII
|
about 50% opacification of the area of the posterior
capsule
|