James M. Tielsch

National study of cataract surgery outcomes: Variation in 4-month postoperative outcomes as reflected in multiple outcome measures

BACKGROUNDnAlthough ophthalmologists have long recognized that visual acuity alone is an inadequate measure of visual impairment, the need for and outcomes of cataract surgery historically have been assessed in terms of visual acuity.nnnPURPOSEnTo examine the relation among different cataract surgery outcome measures, including a 14-item instrument designed to measure functional impairment caused by cataract (the VF-14), at 4 months after cataract surgery.nnnMETHODSnThe authors performed a longitudinal study of 552 patients undergoing first eye cataract surgery by 1 of 75 ophthalmologists practicing in Columbus, Ohio, St. Louis, Missouri, or Houston, Texas. Patients were interviewed, and clinical data were obtained preoperatively (July 15, 1991-March 14, 1992) and 4 months postoperatively.nnnRESULTSnThe percentage of patients judged to be improved at 4 months after cataract surgery varied by the outcome measure used: Snellen visual acuity (96%); VF-14 score (89%); satisfaction with vision (85%); self-reported trouble with vision (80%); and Sickness Impact Profile score (67%). The change in patients ratings of their trouble with vision and their satisfaction with vision were correlated more strongly with the change in VF-14 score than with the change in visual acuity (operated eye or better eye). The average change in VF-14 score was unrelated to the preoperative visual acuity in the eye undergoing surgery.nnnCONCLUSIONnEstimates of the proportion of patients benefiting from cataract surgery vary with the outcome measure used to measure benefit. Change in VF-14 score, a measure of functional impairment related to vision, may be a better measure of the benefit of cataract surgery than change in visual acuity.

Biometry and Primary Angle-closure Glaucoma among Chinese, White, and Black Populations

PURPOSEnPrimary angle-closure glaucoma (PACG) is more prevalent among Chinese than whites. The authors tested the hypothesis that Chinese have shallower anterior chambers than do whites, a factor that may be related to PACG prevalence.nnnMETHODSnThe authors compared anterior chamber depth, axial length, radius of corneal curvature, and refractive error among 531 Chinese, 170 whites, and 188 blacks older than 40 years of age using the same model of instruments and identical technique.nnnRESULTSnMean anterior chamber depth and axial length did not differ significantly for the three groups. Whites had a significantly higher prevalence of hyperopia > 2 diopters than did Chinese. Radius of corneal curvature was significantly smaller among Chinese than whites or blacks.nnnCONCLUSIONSnThese results suggest that Chinese do not differ on a population basis from other ethnic groups in many of the biometric risk factors known to be of importance for PACG. It will be necessary to identify other ocular biometric parameters to explain the excess burden of PACG among Chinese, which may improve the effectiveness of screening for this disease in all populations.

Predictors of Outcome in Patients Who Underwent Cataract Surgery

PURPOSEnTo identify preoperative patient characteristics associated with a lack of improvement on one or more measures 4 months after cataract surgery.nnnMETHODSnThe authors collected preoperative and 4-month postoperative information on 552 patients undergoing first-eye cataract surgery from the practices of 72 ophthalmologists in three cities. The principal outcomes assessed were (1) Snellen visual acuity, (2) a cataract-related symptom score (possible range: 0, 0 of 6 symptoms present or bothersome, to 18, all 6 symptoms very bothersome), and (3) a measure of functional impairment in patients with cataract--the VF-14 score (possible range: 0, inability to perform any of the applicable activities, to 100, no difficulty performing any of the applicable activities). Multiple logistic regression was used to assess the association between preoperative patient characteristics and failure to improve on one or more outcome measures. Multiple linear regression was used to estimate the adjusted rate of lack of improvement in one or more outcome measures for one group of patients compared with another.nnnRESULTSnAlthough 91 patients (16.5%) failed to improve on one or more of the outcome measures assessed, only 2 (0.4%) failed to improve on all three measures. The 91 patients who did not improve on at least one measure were approximately one sixth as likely to be satisfied with their vision postoperatively as the 461 patients who improved on all three outcome measures. Preoperative age of 75 years of age or older, VF-14 score of 90 or higher, cataract symptom score of 3 or lower, and ocular comorbidity (glaucoma, diabetic retinopathy, or age-related macular degeneration) were associated independently with increased likelihood of not improving on one or more measure (odds ratio: 3.57, 2.10, 3.29, and 2.16, respectively). The mean adjusted rate of failure to improve on at least one of the outcome measures ranged from 20.5% to 26.5% for patients with these preoperative characteristics compared with 8.8% to 13.8% for those patients without them. The preoperative level of Snellen visual acuity was not associated with the likelihood of not improving on one or more of the outcomes assessed.nnnCONCLUSIONSnThe authors conclude that specific preoperative characteristics (age, comorbidity, cataract symptom score, and VF-14 score) are independent predictors of patient outcome after cataract surgery.

Variation in Cataract Surgery Practice and Clinical Outcomes

PURPOSEnTo examine associations between surgical technique, patient and surgeon characteristics, and clinical outcomes of cataract surgery.nnnMETHODSnSeventy-five ophthalmologists were recruited from three cities based on a sampling scheme stratified by surgeon-reported annual volume of cataract surgery. Seven hundred seventy-two patients undergoing first eye cataract surgery were enrolled, with complete preoperative, perioperative, and 4-month postoperative clinical data on 717 patients (93%).nnnRESULTSnSixty-five percent of surgery was performed by phacoemulsification and 35% by standard extracapsular (ECCE) techniques. Performance of ECCE was associated with the presence of ocular comorbidity and 21 or more years in practice of the surgeon. Performance of phacoemulsification was associated with annual volume of cataract surgery, wherein high-volume (201-399 patients annually) and very high-volume (> 400 patients annually) surgeons had 3.7 and 3.9 times the likelihood of performing phacoemulsification compared with moderate-volume (51-200 cases annually) surgeons. The rates of intraoperative, perioperative, and 4-month postoperative adverse events and the amount of improvement in visual acuity did not differ either by surgical technique or volume stratum. The reported occurrence of posterior capsular opacification within 4 months of surgery was increased in the presence of cortical opacification, one city, and patients operated on by either high- or very high-volume surgeons.nnnCONCLUSIONSnIn this cohort, no difference in clinical outcomes, as measured by change in visual acuity or occurrence of postoperative adverse events (except for posterior capsular opacification), can be attributed to performance of phacoemulsification versus ECCE or to the reported annual volume of cataract surgery of the surgeon. Self-reported high and very high annual volume of cataract surgery is associated independently with performance of phacoemulsification and surgeons report of posterior capsular opacification at 4 months after cataract surgery.

Rate of Progression in Open-angle Glaucoma Estimated From Cross-sectional Prevalence of Visual Field Damage

Purpose To estimate the rate of visual field loss in persons with open-angle glaucoma. Methods The visual field data obtained by Goldmann perimetry from 151 persons with open-angle glaucoma from the Baltimore Eye Survey were graded on a nine-level severity scale. Approximately one half of these persons had previously diagnosed glaucoma and were being treated. Using regression analysis, their scores were compared to other features, including age, vertical cup/disk ratio, treatment status, gender, race, and intraocular pressure. These data were used to estimate the average rate of progressive field loss and blindness in glaucoma. Results Among 112 black subjects, the severity of visual field damage was significantly associated with age (P Conclusions While glaucoma is a frequent cause of visual disability, rate of progressive visual field loss is not sufficient to lead to bilateral blindness in the majority of those affected. Aggressiveness of glaucoma therapy should be related to the rate of visual field loss stressing confirmation of field progression.

Estimating the rate of progressive visual field damage in those with open-angle glaucoma, from cross-sectional data

PURPOSEnTo estimate the rate of visual field progression in open-angle glaucoma (OAG) subjects, by using data from population-based cross-sectional studies.nnnMETHODSnSubjects with OAG were identified in nine surveys of randomly sampled populations using standard criteria for glaucomatous optic neuropathy. Subjects were of European, African, Chinese, and Hispanic ethnicity. The measure of OAG damage was the mean deviation (MD) of an automated visual field test (Humphrey Field Analyzer; Carl Zeiss Meditec, Inc., Dublin, CA). The rate of progression was the mean of all subjects damage in the worse eye divided by an average time since onset. Time since onset was estimated from age-specific prevalence rates.nnnRESULTSnA total of 1066 subjects with OAG contributed visual field data. The mean worsening in decibels per year was: European-derived, -1.12; Hispanic, -1.26; African-derived, -1.33; and Chinese -1.56 (difference among ethnicities, P = 0.16). The mean duration of disease was lowest among Chinese persons at 10.5 years (95% CI: 8.8-12.6) and was highest in African-derived subjects at 15.4 years (95% CI: 14.6-15.9). The progression rate was not consistently related to age or gender. By combining disease duration and progression rate, the model predicted that 15% or fewer of the worse eyes would reach the end of the field damage scale in the patients lifetime.nnnCONCLUSIONSnThe estimates of typical worsening per year in the worse eye among subjects with OAG suggested slightly more rapid progression than in some clinic-based studies. The rate did not differ significantly by ethnicity or gender, but was worse in those with known, treated OAG and in pseudophakic subjects.

Calf Lung Surfactant Extract Prophylaxis and Retinopathy of Prematurity

Retinopathy of prematurity (ROP) is an important cause of blindness among extremely low birth weight infants (birth weight less than or equal to 1000 g). In the 1990s, greater numbers of extremely low birth weight infants will survive, in part due to routine surfactant replacement therapy for neonatal respiratory distress syndrome. Few studies have evaluated the effect of surfactant therapy on the incidence and severity of ROP. The authors performed a review of the records of extremely low birth weight infants born in two 2-year intervals before and after initiation of a clinical protocol in which all extremely low birth weight infants received prophylactic treatment with calf lung surfactant extract (Infasurf). Surfactant therapy was associated with a significant improvement in survival to discharge (79% [88 of 112] versus 63% [82 of 131]; P = 0.01). Compared with control infants, surfactant-treated infants had a significantly lower incidence of any stage of ROP (64% [56 of 87] versus 85% [68 of 80]; P less than 0.004). The incidence of threshold (Stage 3 plus or greater) ROP was substantially reduced (3.4% [3 of 87] versus 10% [8 of 80]; P = 0.16)). The surfactant-associated reduction in ROP was independent of birth weight, gestational age, race, or sex. These data suggest that Infasurf may substantially reduce the incidence and severity of ROP in the extremely low birth weight population.

A self-administered health questionnaire for the preoperative risk stratification of patients undergoing cataract surgery

PURPOSEnTo determine if a self-administered health status questionnaire completed by candidates for cataract surgery is beneficial for identifying medical comorbidities and patients at risk for adverse intraoperative and postoperative medical events.nnnDESIGNnProspective cohort study.nnnMETHODSnData were obtained from a large, randomized clinical trial of 19,250 cataract surgeries performed between June 1, 1995, and June 30, 1997. Preoperative data were obtained from a standardized, self-administered patient health questionnaire and a history and physical form completed by the patients physician. A record of adverse medical events on the day of surgery and through the first 7 postoperative days was recorded.nnnRESULTSnResponses to 21 questions on the questionnaire were highly specific for 12 comorbid conditions identified by the physician history and physical, ranging from 100% specificity for arrhythmia to 91.3% specificity for coronary artery disease. Comorbid conditions identified by the questionnaire were associated with similar relative risks of adverse events as those identified by the physician history and physical. Patients who had no comorbidities identified by the questionnaire had adverse medical event rates indistinguishable from patients with no comorbid conditions identified by the health provider history and physical.nnnCONCLUSIONSnThe self-administered questionnaire showed a high degree of specificity for 12 common comorbid conditions in cataract patients. A questionnaire such as this may be useful in preoperative risk stratification.