Autorefraction-Based Preschool Vision Screening
In this retrospective economic evaluation, Lowry et al. investigated referral criteria in preschool vision screening protocols. They sought to determine the criteria that produced the lowest cost per case detected. They found that commonly used referral criteria were more sensitive than is optimal for cost effectiveness, especially for myopia referrals.
Preschoolers in San Francisco and Oakland received preschool-based Retinomax autorefraction screening with a standard referral protocol and as-needed comprehensive eye examinations in 2012-2013. Positive predictive values and referral criteria that minimized cost per case detected were derived from the San Francisco data. This model of referral criteria was then retrospectively tested in Oakland for cost-effectiveness, with sensitivity analysis, against two other commonly used referral criteria. Cases were defined according to the American Association for Pediatric Ophthalmology and Strabismus (AAPOS) criteria for amblyopia risk factors.
In San Francisco, 3,974 children were screened, 631 referred, and 412 examined. Forty-eight percent of referrals (301 children) met more than one of the referral criteria. Positive predictive values ranged from 7 percent for myopia to 56 percent for astigmatism. In Oakland, 2,359 children were screened, and 269 were examined. When the referral model derived from San Francisco was applied to the study population in Oakland, the cost per case detected was $258. This cost was lower than that of either the original referral criteria or the criteria based on the Vision in Preschoolers study, which were $424 and $371, respectively, per additional case detected.
The authors concluded that more stringent referral criteria may reduce the cost per case detected in vision screening and allow more at-risk children to be detected with the same financial resources.
Bleb-Related Infections After Trabeculectomy
Kim et al. reported the incidence of late-onset bleb-related infections and identified risk factors for bleb-related infections after trabeculectomy for the treatment of glaucoma.
In this retrospective case series, bleb-related infections were defined as blebitis, endophthalmitis, or blebitis with endophthalmitis. A total of 1,959 eyes of 1,423 patients who underwent trabeculectomy and were followed for one year or longer were included. During a mean follow-up period of 5.4 years, 24 eyes were diagnosed with bleb-related infections, of which 15 eyes had blebitis, and nine had endophthalmitis. Among the 15 eyes with blebitis, two eyes developed endophthalmitis while under treatment. The Kaplan-Meier estimated incidence of bleb-related infections was 2 percent at 10 years.
A Cox multivariate analysis showed the significant risk factors for a bleb-related infection to be diagnosis of pigmentary glaucoma or juvenile glaucoma, history of bleb leak, intraocular pressure sustained below the target pressure, chronic blepharitis, and the presence of punctal plugs. Surgical bleb revision demonstrated a protective effect against bleb-related infections when risk factors were present.
The authors warned that clinicians should be constantly vigilant for, and patients made aware of, the possibility of bleb-related infections long after trabeculectomy, especially in the presence of identified risk factors.
Intermediate-Stage AMD in Patients With AIDS
Jabs et al., from the Studies of Ocular Complications of AIDS Research Group, used a cross-sectional study of their patients with AIDS to evaluate the prevalence of intermediate-stage age-related macular degeneration (AMD). They found that the prevalence of intermediate-stage AMD was significantly greater in participants with AIDS than among people who were not infected with HIV.
Intermediate-stage AMD was determined from enrollment retinal photographs by graders at a centralized reading center, using the Age-Related Eye Disease Study grading system. Graders were masked as to clinical data. Of 1,825 participants with AIDS and no ocular opportunistic infections, 9.9 percent had intermediate-stage AMD. Risk factors included age, with the risk increasing every decade; the prevalence of AMD ranged from 4 percent among participants 30 to 39 years old to 24 percent for participants aged 60 years or older. Other risk factors included the HIV risk groups of injection drug use or heterosexual contact. Compared with the HIV-uninfected population in the Beaver Dam Offspring Study, there was an approximately fourfold increased age-adjusted prevalence of intermediate-stage AMD.
This increased prevalence is consistent with findings on higher rates of other age-related diseases in antiretroviral-treated, immune-restored HIV-infected persons compared with non–HIV-infected persons.
Reduced Corneal Endothelial Cell Density in Patients With Dry Eye Disease
Kheirkhah et al. used a cross-sectional controlled study design to evaluate corneal endothelial cell density (ECD) in patients with dry eye disease (DED) compared with a control group. This study showed that in moderate to severe dry eye disease, there is a significant reduction in central corneal endothelial cell density compared with an age- and sex-matched control group. In addition, reduced endothelial cell density was found to have significant correlations with the clinical severity of the dry eye disease.
The study included 90 eyes of 45 patients with moderate to severe DED (mean age, 53.7 years) and 30 eyes of 15 normal controls (mean age, 50.7 years). All participants had a complete ophthalmic evaluation, including corneal fluorescein staining and symptom assessment using the Ocular Surface Disease Index (OSDI). In addition, laser-scanning in vivo confocal microscopy was performed to measure the density of the following parameters in the central cornea: endothelial cells, subbasal nerves, and subbasal immune dendritic cells.
The researchers found that corneal ECD was significantly lower in the DED group than in the control group. The DED group also showed significantly lower corneal subbasal nerve density compared with the control group. However, dendritic cell density was significantly higher in the DED group than in the controls. There were statistically significant correlations between corneal ECD and dry eye severity parameters, including the OSDI score and corneal fluorescein staining.
American Journal of Ophthalmology summaries are edited by Thomas J. Liesegang, MD.
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