Methods

This retrospective study was approved by the University of California, Los Angeles Institutional Review Board and conformed to the requirements of the US Health Insurance Portability and Accountability Act. Written informed consent was obtained from the participants. Strabismic patients were recruited during 2010 through 2012 from the clinics of 4 strabismologists (S.L.P., J.L.D., F.G.V., and S.J.I.) during preoperative visits. Only patients over the age of 50 were included in this study between September 2011 and June 2014, to permit a closer comparison to the NEI VFQ-25 Field Test groups.

Since these quality-of-life surveys were part of a larger study with preexisting exclusion criteria, patients with any known history of treatment for amblyopia, dissociated vertical or dissociated horizontal deviation as the sole form of strabismus, pathologic nystagmus, or neurologic diseases were excluded.

Results

Forty-two patients over the age of 50 with strabismus participated in the study. Demographic and clinical features of these patients are shown in Table 1 . Mean age was 65 years (range 52–90 years). Twenty-two patients (54%) were female. Median binocular visual acuity was 20/20 (range 20/12.5–20/50). Ethnicity was reported as white in 36 patients, Asian in 3 patients, and Hispanic in 3 patients.

Types of strabismus included 15 patients with esotropia, 8 patients with exotropia, 15 patients with hypertropia, and 4 patients with combined vertical and horizontal deviations. Diplopia was reported by 34 patients (81%). Fifteen patients (36%) had measurable stereoacuity at near, and 9 patients (21%) had measurable stereoacuity at distance.

Table 2 compares age, sex, and binocular visual acuity between the strabismic patients and the comparison groups. Age was significantly different between the strabismic patients and all other groups, except glaucoma patients ( P = .29) and low vision patients ( P = .17). Patients with diabetic retinopathy and CMV retinitis were younger than strabismic patients, whereas patients with age-related macular degeneration and cataracts were older than strabismic patients. The sex distribution was not significantly different between strabismic patients and the other groups, except CMV retinitis, in which nearly all patients were male ( P < .0001). Median binocular visual acuity was 20/20 in the strabismic patients, which was the same as CMV retinitis patients, and within 3 lines of the diabetic retinopathy, glaucoma, and cataract groups. Median binocular visual acuity was 20/63 in age-related macular degeneration patients, 6 lines worse than the strabismic patients.

The NEI VFQ-25 subscale scores for strabismic patients and comparison groups are shown in Table 3 . Statistically significant differences between strabismic patients and other groups at a threshold of .0007 (calculated using the Bonferroni correction) are indicated by the shading of cells in the table. Cells shaded dark gray indicate subscale scores that were significantly better than strabismic patients, light gray cells denote subscale scores that were not significantly different from strabismic patients, and white cells indicate subscale scores that were significantly worse than strabismic patients. The Supplemental Table (available at AJO.com ) shows the same comparisons with the P value for significance set to .05. With the exception of the General Health subscale, nearly all subscale scores were significantly worse or not significantly different in strabismic patients compared to patients with diabetic retinopathy, age-related macular degeneration, glaucoma, cataract, and CMV retinitis. The subscale scores that were significantly better in strabismic patients were Driving and Color Vision compared to age-related macular degeneration patients. Additionally, subscale scores were significantly better or not significantly different in patients with strabismus compared to low vision patients, except for the Ocular Pain subscale. Strabismic patients reported significantly worse ocular pain than patients in all other groups.

Nine strabismic patients also had other ocular disorders, including cataract (n = 3), glaucoma (n = 1), age-related macular degeneration (n = 1), dry eye (n = 1), high myopia (n = 1), retinal detachment (n = 1), and blepharoptosis (n = 1). A separate analysis excluding strabismic patients with these confounding ocular diseases found no change in the direction of difference between subscale scores of strabismic patients and the comparison groups.