Ankle-Brachial Index and the Prevalence of Age-Related Maculopathy

TABLE 2. Association of Retinopathy and Vascular Disease in Persons With Impaired Glucose Metabolism Retinopathy

Characteristic

Stroke Present Absent Coronary heart disease Present Absent Angina Present Absent Peripheral arterial disease§ Present Absent Lower limb claudication Present Absent

No. at Risk

%*

Age-Sex Adjusted OR (95% CI)†

P Value

Multivariate-Adjusted OR (95% CI)‡

P Value

42 983

21.4 6.1

4.3 (1.9–9.6) 1.0

.001

4.2 (1.8–9.7) 1.0

.001

55 970

7.3 6.7

1.0 (0.4–3.1) 1.0

.934

0.9 (0.3–2.8) 1.0

.898

62 963

8.1 6.6

1.2 (0.5–3.1) 1.0

.728

1.1 (0.4–3.0) 1.0

.831

28 997

10.7 6.6

1.6 (0.5–5.5) 1.0

.462

1.5 (0.4–5.4) 1.0

.512

42 982

7.1 6.6

1.0 (0.3–3.5) 1.0

.939

1.0 (0.3–3.5) 1.0

.953

*Proportion of persons with retinopathy. † Odds ratio (95% confidence intervals) of having vascular disease, adjusted for age and sex. ‡ Further adjustment for glycated hemoglobin, systolic blood pressure, cigarette smoking. § Peripheral arterial disease defined as ⬍0.9 on the ankle brachial pressure index and/or the criteria for claudication as indicated by the Edinburgh Claudication Questionnaire.7

that retinopathy may be a marker of subclinical cerebrovascular disease. REFERENCES

1. Wong TY, Klein R, Klein BEK, et al. Retinal microvascular abnormalities, and their relation to hypertension, cardiovascular diseases and mortality. Surv Ophthalmol 2001;46:59 – 80. 2. Wong TY, Mitchell P. Hypertensive retinopathy. N Engl J Med 2004;351:2310 –2317. 3. Wong TY, Klein R, Couper DJ, et al. Retinal microvascular abnormalities and incident clinical strokes: the Atherosclerosis Risk in the Communities Study. Lancet 2001;358:1134 – 1140. 4. Dunstan DW, Zimmet PZ, Welborn TA, et al. The Australian Diabetes, Obesity and Lifestyle Study (AusDiab)— methods and response rates. Diabetes Res Clin Pract 2002;57:119 –129. 5. Dunstan DW, Zimmet PZ, Welborn TA, et al, for the AusDiab Study Group. The rising prevalence of diabetes and impaired glucose tolerance. Diabetes Care 2002;25:829 – 834. 6. Tapp RJ, Shaw JE, Harper CA, et al, for the AusDiab Study Group. The prevalence of and factors associated with diabetic retinopathy in the Australian population. Diabetes Care 2003;26:1731–1737. 7. Leng GC, Fowkes FG. The Edinburgh Claudication Questionnaire: an improved version of the WHO/Rose Questionnaire for use in epidemiological surveys. J Clin Epidemiol 1992;45: 1101–1109.

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Ankle-Brachial Index and the Prevalence of Age-Related Maculopathy Scot E. Moss, MA, Ronald Klein, MD, MPH, and Barbara E.K. Klein, MD, MPH PURPOSE: To examine the association of ankle-brachial blood pressure index (ABI) with prevalence of agerelated maculopathy (ARM). DESIGN: A cross-sectional cohort study. METHODS: ABI was measured in 2447 subjects aged 53 to 97 years. ARM was determined from 30-degree color stereoscopic fundus photographs. RESULTS: Low ABI (<0.9) was present in 5.4% of subjects. Early ARM was present in 22.1% of subjects with and 18.8% without low ABI. Late ARM was present in 5.3% of subjects with and 1.7% without low ABI. This result was not statistically significant.

Accepted for publication Jul 11, 2005. From the Department of Ophthalmology and Visual Sciences, University of Wisconsin Medical School, Madison, Wisconsin. Supported in part by National Institutes of Health grant EY06594. Inquiries to Scot E. Moss, MA, University of Wisconsin Madison, Department of Ophthalmology and Visual Sciences, 610 N Walnut Street, 4th Floor WARF, Madison, WI 53726; fax: (608) 263-0279; e-mail: [email protected]

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TABLE 1. Crude and Age-Adjusted Prevalence of Age-Related Maculopathy (ARM) by Low Ankle-Brachial Index (ABI) in the Beaver Dam Eye Study, 1998 –2000 ARM

Low ABI

N

Crude %

Early

No Yes No Yes

2240 124 2278 131

19.1 23.4 1.8 5.3

Late

P Value

.24 ⬍.01

Low ABI does not appear to be a risk factor for ARM. (Am J Ophthalmol 2005;140: 1159 –1161. © 2005 by Elsevier Inc. All rights reserved.) HERE IS EVIDENCE OF A VASCULAR BASIS TO AGE-

related maculopathy (ARM). The Rotterdam Eye Study found increased risk of prevalent late ARM and incident early or late ARM in subjects with carotid artery atherosclerosis.1,2 The ankle-brachial blood pressure index (ABI) is another measure of peripheral atherosclerosis. The purpose of this brief report is to explore the relationship of ABI with the prevalence of ARM and its component lesions. Methods used to identify the population and its description have appeared previously.3,4 A private census of Beaver Dam, Wisconsin, was performed to identify persons 43 to 84 years of age. The baseline examination occurred between March 1, 1988, and September 14, 1990 (n ⫽ 4926). Follow-up examinations occurred in 1993 to 1995 (n ⫽ 3722) and 1998 to 2000 (n ⫽ 2962). The ABI was first obtained at the 10-year examination. Thus, data from that examination form the basis for this analysis, a cross-sectional prevalence study. Institutional review board approval was granted, and informed consent was obtained in accordance with the tenets of the Declaration of Helsinki. ABI was obtained by standard protocol. The Wisconsin Age-Related Maculopathy Grading System was used to assess the presence and severity of lesions associated with ARM.3 Early ARM was defined as presence of soft indistinct drusen or any type of drusen associated with retinal pigment epithelial depigmentation or increased retinal pigment. Late ARM was defined as either exudative maculopathy or geographic atrophy. Analyses were performed by SAS software version 8.1 (SAS Institute, Cary, North Carolina, USA). Age adjustment was performed by the direct method. ABI measurements and ARM gradings were available for 2447 subjects. Subjects with ABI ⬎ 1.5 were excluded (n ⫽ 38) as unreliable as a result of calcification of arterial walls. In the remaining 2409 subjects, age ranged from 53 to 97 years with a mean (SD) of 67.6 (9.1), and 43% were men. Low ABI (ⱕ0.9) was present 1160

AMERICAN JOURNAL

P Value

21.3 18.3 2.2 3.7

.46 .17

in 131 (5.4%) of subjects. The Table presents prevalence of ARM by low ABI status. Low ABI is not associated with crude or age-adjusted early ARM. Late ARM was present in 5.3% (n ⫽ 7) and 1.8% (n ⫽ 38) of subjects with and without low ABI, respectively (P ⬍ .01) (Table). However, the association was not statistically significant after age adjustment (P ⫽ .17). There were no significant crude or age-adjusted relationships with soft indistinct drusen, increased retinal pigment, or retinal pigment epithelial depigmentation (data not shown). Further control for sex, smoking, heavy alcohol consumption, and use of statin drugs did not alter any of the above results (data not shown). Analysis of ABI in quartiles and as a continuous variable produced similar results. ABI has been shown to be an indicator of peripheral vascular disease.5 Whether this includes ARM is an open question. The Rotterdam Eye Study found evidence for an associated with ARM. That study showed a statistically significant 2.0 times increased odds of late ARM in subjects with low ABI after adjusting for age and sex.1 This is in contrast to the present study, which did not find a significant association between ABI and late ARM after controlling for age and additional variables. It is possible that we may have found a relationship had more cases of late ARM been available. The Rotterdam Eye Study did not perform a prevalence analysis for early ARM. However, a later article from the same study reported on the incidence of early or late ARM with respect to ABI.2 It did not find an association of low ABI with incident ARM. However, when ABI was analyzed in tertiles, the lowest tertile was found to have significantly higher incidence of ARM compared with the highest. The current study did not find an association between ABI and prevalence of early ARM. We conclude that there is conflicting evidence for an association between ABI and ARM.

CONCLUSIONS:

T

Age-Adjusted %

REFERENCES

1. Vingerling JR, Dielemans I, Bots ML, et al. Age-related macular degeneration is associated with atherosclerosis: the Rotterdam Study. Am J Epidemiol 1995;142:404 – 409. OF

OPHTHALMOLOGY

DECEMBER 2005

2. van Leeuwen R, Ikram MK, Vingerling JR, et al. Blood pressure, atherosclerosis, and the incidence of age-related maculopathy: the Rotterdam Study. Invest Ophthalmol Vis Sci 2003;44:3771–3777. 3. Klein R, Klein BE, Linton KL. Prevalence of age-related maculopathy: the Beaver Dam Eye Study. Ophthalmology 1992;99:933–943. 4. Klein R, Klein BE, Tomany SC, Meuer SM, Huang GH. Ten-year incidence and progression of age-related maculopathy: the Beaver Dam Eye Study. Ophthalmology 2002; 109:1767–1779. 5. Zheng ZJ, Sharrett AR, Chambless LE, et al. Associations of ankle-brachial index with clinical coronary heart disease, stroke and preclinical carotid and popliteal atherosclerosis: the Atherosclerosis Risk in Communities (ARIC) Study. Atherosclerosis 1997;131:115–125.

Performing Vitreous Biopsy by Perfluorocarbon-Perfused Vitrectomy Hugo Quiroz-Mercado, MD, Jorge Rivera-Sempertegui, MD, Tamer A. Macky, MD, FRCSEd, Patricia Navarro-López, MD, Lidia Griselda-Alvarez, MD, Nayeli Ibarra-Ponce, MD, and Daniel Moreno-Páramo, MD PURPOSE: To evaluate the safety and efficacy of perfluorocarbon-perfused vitrectomy (PCPV) as a novel technique in obtaining a large undiluted vitreous biopsy. DESIGN: Cross-sectional interventional study. METHODS: Patients with undiagnosed posterior uveitis scheduled for vitreous biopsy underwent PCPV. A syringe containing 5 ml of perfluorocarbon liquid (PCL) was connected to the infusion line. Aspiration of the central and superior vitreous was initiated with simultaneous infusion of the PCL. RESULTS: Twenty eyes of 20 patients were included in this study. The mean ⴞ SD amount of PCL used in each eye was 4.50 ⴞ 0.69 ml. The volume of vitreous sample obtained in each eye was 2.25 ⴞ 0.413 ml. No complications occurred.

Accepted for publication Jul 12, 2005. From the Retina Service, Asociación Para Evitar la Ceguera, Mexico City, Mexico (H.Q.-M., J.R.-S., P.N.-L., L.G.-A., N.I.-P., D.M.-P.); and the Department of Ophthalmology, Kasr El Aini Hospital, Cairo University, Cairo, Egypt (T.A.M.). Inquiries to Hugo Quiroz-Mercado, MD, Retina Service, Asociación Para Evitar la Ceguera en Mexico, Hospital “Dr. Luis Sanchez Bulnes,” Vicente Garcia Torres 46, San Lucas Coyoacan 04030, Coyoacan, Mexico City, Mexico; fax: 00-5255-5659-5928; e-mail: retinamex@ yahoo.com

VOL. 140, NO. 6

CONCLUSIONS: PCPV is a safe and effective method for obtaining large undiluted vitreous biopsy. (Am J Ophthalmol 2005;140:1161–1163. © 2005 by Elsevier Inc. All rights reserved.)

H

ISTOLOGIC, CYTOLOGIC, AND IMMUNOLOGIC EVALU-

ation of the vitreous is increasingly important for the diagnosis of inflammatory, infectious, and neoplastic diseases of the posterior pole. However, the small samples obtained with the current described techniques1– 4 may be inadequate for the diagnosis. Perfluorocarbon-perfused vitrectomy (PCPV)5,6 is a technique in which balanced salt solution is replaced with perfluorocarbon liquid (PCL) during vitreous aspiration. In the original technique, large amounts of PCL were used. Here, we describe a novel technique that uses small amounts (3 to 5 ml) of PCL to obtain a large vitreous biopsy. The study protocol was approved by the institutional review board of the hospital “Luis Sanchez Bulnes,” Mexico City, Mexico. All patients received a thorough explanation of the study design, and all provided written informed consent in accordance with the tenets of the Declaration of Helsinki. Twenty eyes of 20 patients scheduled for vitreous biopsy procedure with undiagnosed posterior uveitis were included in this study. A total of 3 to 5 ml of PCL (Perfluoron, Alcon Inc, Ft. Worth, Texas) was placed in a syringe that was connected to the infusion line to be injected into the vitreous cavity as vitreous was aspirated by the vitrectomy probe (Figure 1a). Aspiration of the vitreous sample was always from the center of the vitreous to avoid the simultaneously injected PCL into the vitreous. Vitreous was collected from the aspiration line of the vitrectomy probe by another syringe. Because both substances have different specific gravities, a clear interface between the vitreous and the PCL could be observed (Figure 1b). Separation of the vitreous from the PCL was performed immediately at the pathology laboratory by two methods. First, the syringe was maintained in a vertical position to keep the PCL at the bottom while the vitreous being expressed through a tubing system from the top (Figure 1c). The PCL meniscus was not allowed to enter into the tube. The vitreous remnants were then expressed out of the tube by air. Second, the samples were frozen, and any PCL was easily expressed because it remained unfrozen. Twenty eyes of 20 patients were included in this study. Patients had a mean age of 47.8 years (range 25 to 29 years). The mean amount of PCL used in each eye was 4.50 ⫾ 0.69 ml (range 3 to 5 ml, median 5.0 ml). The mean ⫾ SD volume of vitreous sample obtained in

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