Faculty Bibliography

Purpose:Choroidal thinning has been associated with reticular pseudodrusen (RPD) and β-peripapillary atrophy (β-PPA), which have been linked to normal-tension glaucoma (NTG). This analysis sought to determine whether RPD are independently associated with β-PPA in early AMD patients. Secondary outcomes included the association of RPD and preexisting diagnosis of glaucoma, cup-to-disc ratio (CDR), subfoveal choroidal thickness (SFCT), and IOP. Methods:This prospective cross-sectional study examined 78 age- and sex-matched early AMD patients: 43 RPD patients (63 eyes) and 35 non-RPD patients (64 eyes). Exclusion criteria included advanced AMD, high myopia, and vitreoretinal conditions/surgery. RPD and non-RPD groups were identified by confocal scanning laser ophthalmoscopy. β-PPA as well as CDR were graded on digital, nonstereoscopic fundus photos. SFCT was measured on spectral-domain optical coherence tomography for 69 patients (35 RPD and 34 non-RPD). IOP and glaucoma diagnosis were extracted from charts. Results:β-PPA had a greater prevalence in RPD than non-RPD (44% vs. 19%, P = 0.002); however, this relationship was not significant when SFCT was added to the model (P = 0.150). A preexisting diagnosis of glaucoma (P = 0.156), CDR (P = 0.176), and IOP (P = 0.98) was not different between groups. Conclusions:RPD in early AMD are associated with presence of β-PPA, but choroidal thickness is a confounder in this relationship. Because β-PPA is a common finding in NTG, focusing on a potential shared pathway between RPD and NTG could improve the understanding of pathophysiology and expand therapies for each condition.

PURPOSE: To create a multivariable predictive model for glaucoma in an exclusively African American population and to compare the performance of the model with individual structural parameters derived from SD-OCT. PATIENTS AND METHODS: A total of 103 healthy eyes and 118 glaucomatous eyes of African American patients underwent SD-OCT optic disc and macular scanning. Twenty-seven optic nerve head, retinal nerve fiber layer (RNFL), and ganglion cell parameters were collected. A multivariable model was derived using a backward elimination variable selection procedure. Areas under the curve were used to measure the diagnostic performance of the individual parameters and the multivariable model. RESULTS: The best performing parameters for glaucoma patients included inferior quadrant thickness (AUC=0.9239), average RNFL thickness (AUC=0.9209), sup2 RNFL thickness (AUC=0.9157), superior quadrant thickness (AUC=0.8906), and vertical CDR (AUC=0.8640). The best performing parameters for early glaucoma patients were sup2 RNFL thickness (AUC=0.8680), inferior quadrant thickness (AUC=0.8571), average RNFL thickness (AUC=0.8550), superior quadrant thickness (AUC=0.8420), and inf2 RNFL thickness (AUC=0.8420). The AUC of the multivariable model was 0.8918 for early glaucoma and 0.9744 for moderate/advanced glaucoma. There was some variability in the performance of the model based on disc size. CONCLUSIONS: These findings confirm that several individual RNFL, ONH, and GCA parameters have excellent diagnostic performance in differentiating glaucomatous patients from healthy patients in African American population. A multivariable model was developed and validated with high diagnostic accuracy.

PURPOSE/OBJECTIVE:There are well-established differences in optic nerve morphology between patients of African and European descent. Spectral domain optical coherence tomography (OCT) scanning has demonstrated these differences with respect to optic disc area (DA), average cup-disc ratio, cup volume, and nerve fiber layer thickness. However, the term "African descent" describes a heterogenous group with considerable variability. This study evaluates differences in optic nerve and retinal nerve fiber layer (RNFL) parameters as measured by Cirrus HD-OCT between Caribbean black and African American patients. DESIGN AND METHODS/METHODS:A total of 25 African American subjects and 25 Caribbean black subjects with normal ocular examinations were consecutively recruited to this study. All patients received imaging of the optic nerve and nerve fiber layer with Cirrus HD-OCT. Optic nerve and RNFL parameters were evaluated for statistically significant differences using a t test. A mixed effect model for correlated data was then created to adjust outcome variables for (1) repeated measures and (2) optic nerve size. Two one-sided t tests were then utilized to determine equivalence. RESULTS:After adjustment for DA, RNFL thickness, cup volume, DA, inferior nerve fiber layer, and vertical cup-disc ratio demonstrated statistically significant equivalence between the 2 groups (P value <0.05). The superior nerve fiber layer quadrant was significantly different between the 2 groups and may merit further investigation. CONCLUSIONS:Findings of this study suggest that optic nerve and RNFL morphology is markedly similar between Caribbean blacks and African Americans once adjusted for optic nerve size but cannot be considered equivalent in all measures, particularly in the superior nerve fiber layer.

IMPORTANCE/OBJECTIVE:The Tube vs Trabeculectomy Trial (TVT) found that the 350-mm2 Baerveldt implant (tube) and trabeculectomy with mitomycin may be similarly effective in lowering intraocular pressure in primary open-angle glaucoma. However, to date, there are no published long-term clinical data on the cost-effectiveness of trabeculectomy with mitomycin vs tube insertion. OBJECTIVE:To assess the cost-effectiveness of these procedures compared with maximal medical treatment. DESIGN, SETTING, AND PARTICIPANTS/METHODS:We used the Markov cohort model with a 5-year time horizon to study a hypothetical cohort of 100 000 patients who required glaucoma surgery. MAIN OUTCOMES AND MEASURES/METHODS:Quality-adjusted life-years (QALYs) gained, costs from the societal perspective, and the incremental cost-effectiveness ratio of medical treatment, trabeculectomy, and tube insertion. Costs were identified from Medicare Current Procedural Terminology and Ambulatory Payment Classification reimbursement codes and Red Book medication costs. The QALYs were based on visual field and visual acuity outcomes. The hypothetical societal limit to resources was included using a willingness-to-pay threshold of $50 000 per QALY. Costs and utilities were discounted at 3% per year. Uncertainty was assessed using deterministic sensitivity analyses. RESULTS:The mean costs for medical treatment, trabeculectomy, and tube insertion were $6172, $7872 and $10 075, respectively; these amounts resulted in a cost difference of $1700 (95% CI, $1644-$1770) for medical treatment vs trabeculectomy, $3904 (95% CI, $3858-$3953) for medical treatment vs tube insertion, and $2203 (95% CI, $2121-$2261) for trabeculectomy vs tube insertion. The mean 5-year probability of blindness was 4% for both surgical procedures and 15% for medical treatment. The utility gained after medical treatment, trabeculectomy, and tube insertion was 3.10, 3.30, and 3.38 QALYs, respectively. The incremental cost-effectiveness ratio was $8289 per QALY for trabeculectomy vs medical treatment, $13 896 per QALY for tube insertion vs medical treatment, and $29 055 per QALY for tube insertion vs trabeculectomy. The cost-effectiveness of each surgical procedure was most sensitive to early and late surgical failure rates and was minimally affected by adverse events, rates of visual field progression, or medication costs. CONCLUSIONS AND RELEVANCE/CONCLUSIONS:Assuming a willingness to pay of $50 000 per QALY, trabeculectomy and tube insertion are cost-effective compared with medical treatment alone. Trabeculectomy, however, is cost-effective at a substantially lower cost per QALY compared with tube insertion. More research is necessary to reliably account for patient preferences between the 2 operations.