TY - JOUR
T1 - Population-based Incidence of Intraocular Lens Exchange in Olmsted County, Minnesota
AU - Bothun, Erick D.
AU - Cavalcante, Lilian C.B.
AU - Hodge, David O.
AU - Patel, Sanjay V.
N1 - Funding Information:
The population-based incidence of intraocular lens exchange has increased over the last 3 decades but remains at a low and acceptable rate. Although the incidence rate appears 3 times higher between the first and last decades of the study period, the small number of cases resulted in wide confidence intervals, and thus the exact change in incidence could be less than 3-fold. Nevertheless, the overall increase in incidence was statistically significant and could have several explanations, including increasing complications of primary cataract surgery or increasing surgeon comfort with exchanging lenses (ie, a lower threshold for intervention). However, the major contributing factor is likely to be the increase in the population at risk (ie, subjects who have undergone cataract surgery). The population-based incidence of cataract surgery has doubled over the same period in Olmsted County, 2,3 suggesting that the risk of intraocular lens exchange has remained relatively stable. Indeed, the 30-year cumulative probability of an intraocular lens exchange was 1.5%, increasing at a relatively constant rate of approximately 0.3% per 5-year period. Similarly, Szigiato and associates estimated the 5-year risk of a secondary intraocular lens procedure to be <1%, 7 which included intraocular lens repositioning procedures in addition to intraocular lens exchange. The indications for intraocular lens exchange changed over the study period, reflecting changing patterns of cataract surgery, technology, and expectations. All dislocated lenses associated with capsular tears occurred after 1995, after conversion to using phacoemulsification and foldable lenses. Similarly, the majority of capsular bag/lens complex dislocations in the setting of pseudoexfoliation syndrome occurred after 2010. Two new indications emerged in the final decade of this study: unplanned refractive error and uveitis-glaucoma-hyphema syndrome. Intraocular lens exchange for unplanned refractive error typically took place within days of the primary surgery and is associated with the changing nature of cataract surgery, with patients and surgeons expecting specific refractive outcomes. Jones and associates noted the same trend. 14 A uveitis-glaucoma-hyphema syndrome related to the increasing use of single-piece intraocular lenses with squared-edged haptics was responsible for 5 intraocular lens exchanges in this study, all occurring after 2011. All 5 of these lenses were found to have been partially placed in the ciliary sulcus and were not exchanged until 6–15 years after primary cataract surgery. Surgeons should therefore recognize the late presentation of this condition and the need to verify haptic placement during primary cataract surgery. There was only 1 case of opacified intraocular lens in this study, occurring in a hydrophilic acrylic lens exposed to intraocular gas; the majority of intraocular lenses implanted in Olmsted County are hydrophobic acrylic, which potentially reduced the risk of lens opacity associated with intraocular gas associated with retina and cornea surgery. 15 Complications of intraocular lens exchange were not infrequent in this study, although only 2 eyes suffered profound loss of vision. Additional surgery was required in several cases, for repeat lens dislocation, corneal edema, retinal detachment, and glaucoma. The overall number of complications was too small to determine changing trends over the course of the study. Our study reports population-based incidence for intraocular lens exchange, giving a true representation of the frequency and indications for this surgery, in contrast to reports from tertiary referral series. For example, Fernández-Buenaga and associates reported that intraocular lens opacification accounted for 29% of pseudophakic intraocular lens exchanges in their referral-based series 6 ; in contrast, we found that intraocular lens opacification accounted for only 1.3% of exchanges in our population-based series. However, our study is not without limitations. The relatively small number of cases resulted in somewhat broad confidence intervals, which prevented an accurate estimate of the change in rate of intraocular lens exchange and its indications over the course of the study. Although we estimated the cumulative risk of needing an intraocular lens exchange from within the population having cataract surgery in Olmsted County, we could not account for subjects who may have left the county and had an intraocular lens exchange elsewhere; the cumulative probability may therefore be slightly underestimated. In addition, our results can only be extrapolated to the semi-urban United States white population because the population of Olmsted County is predominantly white; nevertheless, the results are applicable to a large proportion of the United States population. Ophthalmologists should also be aware that phakic intraocular lenses sometimes require explantation 16 ; our series only reported on pseudophakic intraocular lens exchange. This study provides epidemiologic data from a population in the United States without being affected by referral bias and yielding valuable information despite the study limitations. Although the overall incidence of intraocular lens exchange has increased over the last 3 decades, the probability of needing a lens exchange within the population having cataract surgery has remained relatively constant. Surgeons should be aware of newer indications for lens exchange, including unplanned refractive error and uveitis-glaucoma-hyphema syndrome from squared-edged haptics in the ciliary sulcus. Funding/Support: Supported in part by an unrestricted departmental grant from Research to Prevent Blindness, New York, New York. This study was made possible using the resources of the Rochester Epidemiology Project, which is supported by the National Institute on Aging of the National Institutes of Health under award number R01AG034676. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Financial Disclosures: None of the authors has any financial disclosures. The authors attest that they meet the current ICMJE criteria for authorship.
Publisher Copyright:
© 2017 Elsevier Inc.
PY - 2018/3
Y1 - 2018/3
N2 - Purpose: To determine the population-based incidence of pseudophakic intraocular lens exchange in Olmsted County, Minnesota. Design: Retrospective review of a population-based cohort. Methods: Patients undergoing pseudophakic intraocular lens exchange in Olmsted County, Minnesota, between January 1, 1986 and December 31, 2016 were identified from the Rochester Epidemiology Project medical record linkage system. Indications and outcomes were determined, and the incidence rate was calculated as cases per 1 000 000 person-years. Poisson regression analysis was used to assess changes in incidence over time, and the cumulative probability of needing a lens exchange was estimated by Kaplan-Meier analysis. Results: Eighty cases of intraocular lens exchange were identified, yielding an overall age- and sex-adjusted incidence rate of 28.4 per million (confidence interval [CI], 22.1–34.7), which increased over the study period (P =.04). The 30-year cumulative probability of intraocular lens exchange among patients undergoing cataract surgery was 1.5% (CI, 0.6%–2.4%), increasing at a relatively constant rate. Dislocated lenses accounted for 72.5% of lens exchanges. Unplanned refractive outcome of primary cataract surgery and uveitis-glaucoma-hyphema syndrome from squared-edged haptics emerged as newer indications for intraocular lens exchange. Conclusions: The population-based incidence of pseudophakic intraocular lens exchange has increased over the last 30 years, and can be explained by the increase in incidence rate of cataract surgery over the same period. Surgeons should be aware of emerging indications of intraocular lens exchange, which reflect changes in lens design and increasing expectations of refractive outcomes.
AB - Purpose: To determine the population-based incidence of pseudophakic intraocular lens exchange in Olmsted County, Minnesota. Design: Retrospective review of a population-based cohort. Methods: Patients undergoing pseudophakic intraocular lens exchange in Olmsted County, Minnesota, between January 1, 1986 and December 31, 2016 were identified from the Rochester Epidemiology Project medical record linkage system. Indications and outcomes were determined, and the incidence rate was calculated as cases per 1 000 000 person-years. Poisson regression analysis was used to assess changes in incidence over time, and the cumulative probability of needing a lens exchange was estimated by Kaplan-Meier analysis. Results: Eighty cases of intraocular lens exchange were identified, yielding an overall age- and sex-adjusted incidence rate of 28.4 per million (confidence interval [CI], 22.1–34.7), which increased over the study period (P =.04). The 30-year cumulative probability of intraocular lens exchange among patients undergoing cataract surgery was 1.5% (CI, 0.6%–2.4%), increasing at a relatively constant rate. Dislocated lenses accounted for 72.5% of lens exchanges. Unplanned refractive outcome of primary cataract surgery and uveitis-glaucoma-hyphema syndrome from squared-edged haptics emerged as newer indications for intraocular lens exchange. Conclusions: The population-based incidence of pseudophakic intraocular lens exchange has increased over the last 30 years, and can be explained by the increase in incidence rate of cataract surgery over the same period. Surgeons should be aware of emerging indications of intraocular lens exchange, which reflect changes in lens design and increasing expectations of refractive outcomes.
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U2 - 10.1016/j.ajo.2017.12.016
DO - 10.1016/j.ajo.2017.12.016
M3 - Article
AN - SCOPUS:85041402603
SN - 0002-9394
VL - 187
SP - 80
EP - 86
JO - American Journal of Ophthalmology
JF - American Journal of Ophthalmology
ER -