LOCS III 白内障分级 权威

Clinical application of the Lens Opacities Classification System III in the performance of phacoemulsification

James A.Davison,MD,Leo T.Chylack Jr.,MD

Purpose:To report the correlation of features of cataracts graded by the Lens Opacities Classification System,version III (LOCS III),with phacoemulsification energy expenditure and the balanced salt solution (BSS ®)volume used during cataract surgery.

Setting:Wolfe Clinic,Marshalltown,Iowa,USA.

Methods:This was a retrospective review of 2364cases operated on by a single surgeon from January 1998to July 2000in which the cataract had been graded at the slitlamp using the 4grading scales of the LOCS III:nuclear opalescence (NO),nuclear color (NC),cortical cataract (C),and posterior subcapsular cataract (P).Polynomial best-fit lines were derived using regression analysis correlating the 4preoperative LOCS III characteristics with 3intraoperative observations:ma-chine-measured phacoemulsification time,mean power expenditure,and BSS volume.

Results:As determined by best-fit lines and their coefficient of determination (R 2),there were exponential relationships between machine-measured phaco-emulsification time and the degree of NC (R 2ϭ0.48)and NO (R 2ϭ0.40).Trends existed between NC and NO and the amount of BSS used (R 2ϭ0.08and R 2ϭ0.07,respectively).No relationships were observed between the LOCS III classes of cataract,C and P,at any intraoperative observation.

Conclusions:Exponentially,greater phacoemulsification energy was required as NC and NO increased.The LOCS III cataract grading system enhanced the ability to estimate ultrasonic energy expenditure and BSS volume use during phaco-emulsification.Preoperative LOCS III cataract classification can help to create a more formally organized,integrated,customized operative plan.J Cataract Refract Surg 2003;29:138–145©2003ASCRS and ESCRS

T

he Lens

Opacities

Classification System,version

III (LOCS

III),is

a widely

used,scientifically

valid,standardized

photographic comparison

system

for grad-ing

the features

of the

human age-related

cataract.1–5

It has

been used to grade the type and severity of cataract in

cross-sectional studies and the progression of cataract in longitudinal studies.It also has been used to grade cata-racts at the slitlamp.3

Grading using LOCS III involves the assessment of 4features shown on 3sets of photographs on an 8.5-inch ϫ11-inch color transparency (Figure 1).The features of nuclear opacification and brunescence are graded according to 1set of 6photographs.The bright-ness of scatter from the nuclear region has been desig-nated nuclear opalescence (NO)and the intensity of brunescence,nuclear color (NC).The amount of corti-cal cataract (C)is determined by comparing the esti-mated aggregate of cortical spoking to that seen in

Accepted for publication September 12,2002.From the Wolfe Clinic,Marshalltown,Iowa,USA.

Presented at the Symposium on Cataract,IOL and Refractive Surgery,San Diego,California,USA,April 2001

Reprint requests to James A.Davison,MD Wolfe Clinic,309East Church Street,Marshalltown,Iowa,USA.

©2003ASCRS and ESCRS

0886-3350/03/$–see front matter Published by Elsevier Science Inc.

doi:10.1016/S0886-3350(02)01839-4