The Impact of Social Vulnerability on Structural and Functional Glaucoma Severity, Worsening, and Variability

PURPOSE

To determine the association between social vulnerability index (SVI) and baseline severity, worsening, and variability of glaucoma, as assessed by visual field (VF) and optical coherence tomography (OCT).

DESIGN

Retrospective longitudinal cohort study.

PARTICIPANTS

Adults with glaucoma or glaucoma suspect status in one or both eyes. VFs were derived from 7,897 eyes from 4,482 patients, while OCTs were derived from 6,271 eyes from 3,976 patients. All eyes had a minimum of 5 tests over follow-up using either the Humphrey Field Analyzer or the Cirrus HD-OCT.

METHODS

SVI, which measures neighborhood-level environmental factors, was linked to patient addresses at the census tract level. Rates of change in mean deviation (MD) and retinal nerve fiber layer (RNFL) thickness were computed using linear regression. The slope of the regression line was used to assess worsening, while the standard deviation (SD) of residuals was used as a measure of variability. Multivariable linear mixed-effects models were used to investigate the impact of SVI on baseline, worsening, and variability in both MD and RNFL. We further explored the interaction effect of mean IOP and SVI on worsening in MD and RNFL.

MAIN OUTCOME MEASURES

Glaucoma severity defined based on baseline MD and RNFL thickness. Worsening defined as MD and RNFL slope. Variability defined as the SD of the residuals obtained from MD and RNFL slopes.

RESULTS

Increased (worse) SVI was significantly associated with worse baseline MD (β = -1.07 dB, 95% CI: [-1.54, -0.60]), thicker baseline RNFL (β = 2.46 μm, 95% CI: [0.75, 4.17]), greater rates of RNFL loss (β = -0.12 μm, 95% CI: [-0.23, -0.02]), and greater VF variability (β = 0.16 dB, 95% CI: [0.07, 0.24]). Having worse SVI was associated with worse RNFL loss with increases in IOP (βinteraction = -0.07, [95% CI: -0.12, -0.02]).

CONCLUSIONS

Increased social vulnerability index score is associated with worse functional (VF) loss at baseline, higher rates of structural (OCT) worsening over time, higher VF variability, and a greater effect of IOP on RNFL loss. Further studies are needed to enhance our understanding of these relationships and establish their cause.

Opportunities for Improving Glaucoma Clinical Trials via Deep Learning-Based Identification of Patients with Low Visual Field Variability

PURPOSE

Develop and evaluate the performance of a deep learning model (DLM) that forecasts eyes with low future visual field (VF) variability, and study the impact of using this DLM on sample size requirements for neuroprotective trials.

DESIGN

Retrospective cohort and simulation study.

METHODS

We included 1 eye per patient with baseline reliable VFs, OCT, clinical measures (demographics, intraocular pressure, and visual acuity), and 5 subsequent reliable VFs to forecast VF variability using DLMs and perform sample size estimates. We estimated sample size for 3 groups of eyes: all eyes (AE), low variability eyes (LVE: the subset of AE with a standard deviation of mean deviation [MD] slope residuals in the bottom 25th percentile), and DLM-predicted low variability eyes (DLPE: the subset of AE predicted to be low variability by the DLM). Deep learning models using only baseline VF/OCT/clinical data as input (DLM1), or also using a second VF (DLM2) were constructed to predict low VF variability (DLPE1 and DLPE2, respectively). Data were split 60/10/30 into train/val/test. Clinical trial simulations were performed only on the test set. We estimated the sample size necessary to detect treatment effects of 20% to 50% in MD slope with 80% power. Power was defined as the percentage of simulated clinical trials where the MD slope was significantly worse from the control. Clinical trials were simulated with visits every 3 months with a total of 10 visits.

RESULTS

A total of 2817 eyes were included in the analysis. Deep learning models 1 and 2 achieved an area under the receiver operating characteristic curve of 0.73 (95% confidence interval [CI]: 0.68, 0.76) and 0.82 (95% CI: 0.78, 0.85) in forecasting low VF variability. When compared with including AE, using DLPE1 and DLPE2 reduced sample size to achieve 80% power by 30% and 38% for 30% treatment effect, and 31% and 38% for 50% treatment effect.

CONCLUSIONS

Deep learning models can forecast eyes with low VF variability using data from a single baseline clinical visit. This can reduce sample size requirements, and potentially reduce the burden of future glaucoma clinical trials.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Assessment of linear regression of peripapillary optical coherence tomography retinal nerve fiber layer measurements to forecast glacuoma trajectory

Linear regression of optical coherence tomography measurements of peripapillary retinal nerve fiber layer thickness is often used to detect glaucoma progression and forecast future disease course. However, current measurement frequencies suggest that clinicians often apply linear regression to a relatively small number of measurements (e.g., less than a handful). In this study, we estimate the accuracy of linear regression in predicting the next reliable measurement of average retinal nerve fiber layer thickness using Zeiss Cirrus optical coherence tomography measurements of average retinal nerve fiber layer thickness from a sample of 6,471 eyes with glaucoma or glaucoma-suspect status. Linear regression is compared to two null models: no glaucoma worsening, and worsening due to aging. Linear regression on the first M ≥ 2 measurements was significantly worse at predicting a reliable M+1st measurement for 2 ≤ M ≤ 6. This range was reduced to 2 ≤ M ≤ 5 when retinal nerve fiber layer thickness measurements were first "corrected" for scan quality. Simulations based on measurement frequencies in our sample-on average 393 ± 190 days between consecutive measurements-show that linear regression outperforms both null models when M ≥ 5 and the goal is to forecast moderate (75th percentile) worsening, and when M ≥ 3 for rapid (90th percentile) worsening. If linear regression is used to assess disease trajectory with a small number of measurements over short time periods (e.g., 1-2 years), as is often the case in clinical practice, the number of optical coherence tomography examinations needs to be increased.

Deep learning-based identification of eyes at risk for glaucoma surgery

To develop and evaluate the performance of a deep learning model (DLM) that predicts eyes at high risk of surgical intervention for uncontrolled glaucoma based on multimodal data from an initial ophthalmology visit. Longitudinal, observational, retrospective study. 4898 unique eyes from 4038 adult glaucoma or glaucoma-suspect patients who underwent surgery for uncontrolled glaucoma (trabeculectomy, tube shunt, xen, or diode surgery) between 2013 and 2021, or did not undergo glaucoma surgery but had 3 or more ophthalmology visits. We constructed a DLM to predict the occurrence of glaucoma surgery within various time horizons from a baseline visit. Model inputs included spatially oriented visual field (VF) and optical coherence tomography (OCT) data as well as clinical and demographic features. Separate DLMs with the same architecture were trained to predict the occurrence of surgery within 3 months, within 3-6 months, within 6 months-1 year, within 1-2 years, within 2-3 years, within 3-4 years, and within 4-5 years from the baseline visit. Included eyes were randomly split into 60%, 20%, and 20% for training, validation, and testing. DLM performance was measured using area under the receiver operating characteristic curve (AUC) and precision-recall curve (PRC). Shapley additive explanations (SHAP) were utilized to assess the importance of different features. Model prediction of surgery for uncontrolled glaucoma within 3 months had the best AUC of 0.92 (95% CI 0.88, 0.96). DLMs achieved clinically useful AUC values (> 0.8) for all models that predicted the occurrence of surgery within 3 years. According to SHAP analysis, all 7 models placed intraocular pressure (IOP) within the five most important features in predicting the occurrence of glaucoma surgery. Mean deviation (MD) and average retinal nerve fiber layer (RNFL) thickness were listed among the top 5 most important features by 6 of the 7 models. DLMs can successfully identify eyes requiring surgery for uncontrolled glaucoma within specific time horizons. Predictive performance decreases as the time horizon for forecasting surgery increases. Implementing prediction models in a clinical setting may help identify patients that should be referred to a glaucoma specialist for surgical evaluation.

The impact of achieving target intraocular pressure on glaucomatous retinal nerve fiber layer thinning in a treated clinical population

PURPOSE

Estimate the effect of being below and above the clinician-set target intraocular pressure (IOP) on rates of glaucomatous retinal nerve fiber layer (RNFL) thinning in a treated real-world clinical population.

DESIGN

Retrospective cohort study METHODS: 3,256 eyes (1,923 patients) with ≥ 5 reliable optical coherence tomography (OCT) scans and 1 baseline visual field test were included. Linear mixed-effects modeling estimated the effects of the primary independent variables (mean target difference [measured IOP - target IOP] and mean IOP, mmHg) on the primary dependent variable (RNFL slope, µm/year) while accounting for additional confounding variables (age, gender, race, baseline RNFL, baseline pachymetry, disease severity). A spline term accounted for differential effects when above (target difference > 0 mmHg) and below (target difference ≤ 0 mmHg) target pressure.

RESULTS

Eyes below and above target had significantly different mean RNFL slopes (-0.44 vs. -0.71 µm/year, p < 0.001). Each 1 mmHg increase above target had a 0.143 µm/year faster rate of RNFL thinning (p < 0.001). Separating by disease severity, suspect, mild, moderate, and advanced glaucoma had 0.135 (p = 0.002), 0.116 (p = 0.009), 0.203 (p = 0.02), and 0.65 (p = 0.22) µm/year faster rates of RNFL thinning per 1 mmHg increase.

CONCLUSION

Being above the clinician-set target pressure is associated with more rapid RNFL thinning in suspect, mild, and moderate glaucoma. Faster rates of thinning were also present in advanced glaucoma but statistical significance was limited by the lower sample size of eyes above target and the OCT floor effect.

Prediction of MIGS outcomes on second eyes using first eyes' response

To evaluate how well outcomes following cataract extraction and microinvasive glaucoma surgery in one eye predict outcomes in sequential second eye. Retrospective study of 78 patients who underwent cataract extraction and microinvasive glaucoma surgery in both eyes. Linear regressions using Pearson correlation coefficients were used to evaluate correlations in intraocular pressure and glaucoma medication change between eyes. Multivariable logistic regression models were used to evaluate the associations between first-eye variables and the likelihood of second-eye surgical success at 6 months. Surgical success was defined as meeting target intraocular pressure without additional medications compared to baseline or secondary surgical interventions. Baseline ocular characteristics were comparable between fellow eyes, with the majority having mild glaucoma. Intraocular pressure changes between fellow eyes at 6 months were modestly correlated between eyes (R = 0.48; P < .001). Changes in glaucoma medications were strongly correlated between eyes at all time points, and month 6 demonstrated the most significant correlation (R = 0.80; P < .001). First and second eye cohorts achieved 82% and 83% surgical success. Multivariate analysis for predictive factors of successful second eye surgery showed patients with successful first eye surgery at 6 months were significantly more likely to have successful second eye surgery (odds ratio, 20.67; P < .001). Reductions in intraocular pressure and glaucoma medications at 6 months following surgery in first eyes are correlated to second eye reductions. Successful surgical outcomes at 6 months following first eye surgeries are strongly associated with successful sequential second eye outcomes.

Forecasting Risk of Future Rapid Glaucoma Worsening Using Early Visual Field, OCT, and Clinical Data

PURPOSE

To assess whether we can forecast future rapid visual field (VF) worsening using deep learning models (DLMs) trained on early VF, OCT, and clinical data.

DESIGN

A retrospective cohort study.

SUBJECTS

In total, 4536 eyes from 2962 patients. Overall, 263 (5.80%) eyes underwent rapid VF worsening (mean deviation slope less than -1 dB/year across all VFs).

METHODS

We included eyes that met the following criteria: (1) followed for glaucoma or suspect status; (2) had at least 5 longitudinal reliable VFs (VF1, VF2, VF3, VF4, and VF5); and (3) had 1 reliable baseline OCT scan (OCT1) and 1 set of baseline clinical measurements (clinical1) at the time of VF1. We designed a DLM to forecast future rapid VF worsening. The input consisted of spatially oriented total deviation values from VF1 (including or not including VF2 and VF3 in some models) and retinal nerve fiber layer thickness values from the baseline OCT. We passed this VF/OCT stack into a vision transformer feature extractor, the output of which was concatenated with baseline clinical data before putting it through a linear classifier to predict the eye's risk of rapid VF worsening across the 5 VFs. We compared the performance of models with differing inputs by computing area under the curve (AUC) in the test set. Specifically, we trained models with the following inputs: (1) model V: VF1; (2) VC: VF1+ Clinical1; (3) VO: VF1+ OCT1; (4) VOC: VF1+ Clinical1+ OCT1; (5) V2: VF1 + VF2; (6) V2OC: VF1 + VF2 + Clinical1 + OCT1; (7) V3: VF1 + VF2 + VF3; and (8) V3OC: VF1 + VF2 + VF3 + Clinical1 + OCT1.

MAIN OUTCOME MEASURES

The AUC of DLMs when forecasting rapidly worsening eyes.

RESULTS

Model V3OC best forecasted rapid worsening with an AUC (95% confidence interval [CI]) of 0.87 (0.77-0.97). Remaining models in descending order of performance and their respective AUC (95% CI) were as follows: (1) model V3 (0.84 [0.74-0.95]), (2) model V2OC (0.81 [0.70-0.92]), (3) model V2 (0.81 [0.70-0.82]), (4) model VOC (0.77 [0.65-0.88]), (5) model VO (0.75 [0.64-0.88]), (6) model VC (0.75 [0.63-0.87]), and (7) model V (0.74 [0.62-0.86]).

CONCLUSIONS

Deep learning models can forecast future rapid glaucoma worsening with modest to high performance when trained using data from early in the disease course. Including baseline data from multiple modalities and subsequent visits improves performance beyond using VF data alone.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Short-Term Outcomes of Hydrus Microstent With and Without Additional Canaloplasty During Cataract Surgery

PRCIS

Compared with phacoemulsification and microstent alone, we observed that phacoemulsification with combined microstent and canaloplasty resulted in a significantly greater reduction in glaucoma medications while maintaining similar rates of intraocular pressure reduction and low complications.

PURPOSE

The purpose of this study was to compare the outcomes of phacoemulsification combined with Hydrus Microstent (Alcon Inc.) implantation alone or in combination with canaloplasty (OMNI Surgical System, Sight Sciences Inc.).

MATERIALS AND METHODS

Retrospective study of mild-to-moderate primary open angle glaucoma patients who underwent phacoemulsification with microstent alone (42 eyes of 42 patients) or in combination with canaloplasty (canaloplasty-microstent, 32 eyes of 32 patients). The mean number of ocular hypotensive medications and intraocular pressure were assessed preoperatively and postoperatively at 1 week and at 1, 3, and 6 months. Complications and secondary surgical interventions were recorded. Outcomes measures included the percentage of unmedicated eyes and surgical success at 6 months. Surgical success was defined as reaching the target intraocular pressure without medications or secondary surgical interventions.

RESULTS

Mean intraocular pressure at 6 months was 14.1±3.5 mm Hg (13% reduction) after microstent alone and 13.6±3.1 mm Hg (17% reduction) after canaloplasty-microstent. Mean medications at 6 months were 0.57±0.9 (67% reduction) after microstent alone and 0.16±0.4 (88% reduction) after canaloplasty-microstent ( P< 0.05). At 6 months, 64.3% of microstent alone and 87.3% of canaloplasty-microstent were off all medications ( P =0.02). Success probabilities at 6 months were 44.5% for microstent alone and 70.0% for canaloplasty-microstent ( P =0.04). No secondary surgical interventions occurred in either group.

CONCLUSIONS

Microstent combined with canaloplasty resulted in a significantly higher rate of medication-free status compared with microstent alone through 6 months.

Predicting Visual Field Worsening with Longitudinal OCT Data Using a Gated Transformer Network

PURPOSE

To identify visual field (VF) worsening from longitudinal OCT data using a gated transformer network (GTN) and to examine how GTN performance varies for different definitions of VF worsening and different stages of glaucoma severity at baseline.

DESIGN

Retrospective longitudinal cohort study.

PARTICIPANTS

A total of 4211 eyes (2666 patients) followed up at the Johns Hopkins Wilmer Eye Institute with at least 5 reliable VF results and 1 reliable OCT scan within 1 year of each reliable VF test.

METHODS

For each eye, we used 3 trend-based methods (mean deviation [MD] slope, VF index slope, and pointwise linear regression) and 3 event-based methods (Guided Progression Analysis, Collaborative Initial Glaucoma Treatment Study scoring system, and Advanced Glaucoma Intervention Study [AGIS] scoring system) to define VF worsening. Additionally, we developed a "majority of 6" algorithm (M6) that classifies an eye as worsening if 4 or more of the 6 aforementioned methods classified the eye as worsening. Using these 7 reference standards for VF worsening, we trained 7 GTNs that accept a series of at least 5 as input OCT scans and provide as output a probability of VF worsening. Gated transformer network performance was compared with non-deep learning models with the same serial OCT input from previous studies-linear mixed-effects models (MEMs) and naive Bayes classifiers (NBCs)-using the same training sets and reference standards as for the GTN.

MAIN OUTCOME MEASURES

Area under the receiver operating characteristic curve (AUC).

RESULTS

The M6 labeled 63 eyes (1.50%) as worsening. The GTN achieved an AUC of 0.97 (95% confidence interval, 0.88-1.00) when trained with M6. Gated transformer networks trained and optimized with the other 6 reference standards showed an AUC ranging from 0.78 (MD slope) to 0.89 (AGIS). The 7 GTNs outperformed all 7 MEMs and all 7 NBCs accordingly. Gated transformer network performance was worse for eyes with more severe glaucoma at baseline.

CONCLUSIONS

Gated transformer network models trained with OCT data may be used to identify VF worsening. After further validation, implementing such models in clinical practice may allow us to track functional worsening of glaucoma with less onerous structural testing.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found after the references.

Comparing the Accuracy of Peripapillary OCT Scans and Visual Fields to Detect Glaucoma Worsening

PURPOSE

To compare the accuracy of detecting moderate and rapid rates of glaucoma worsening over a 2-year period with different numbers of OCT scans and visual field (VF) tests in a large sample of glaucoma and glaucoma suspect eyes.

DESIGN

Descriptive and simulation study.

PARTICIPANTS

The OCT sample comprised 12 150 eyes from 7392 adults with glaucoma or glaucoma suspect status followed up at the Wilmer Eye Institute from 2013 through 2021. The VF sample comprised 20 583 eyes from 10 958 adults from the same database. All eyes had undergone at least 5 measurements over follow-up from the Zeiss Cirrus OCT or Humphrey Field Analyzer.

METHODS

Within-eye rates of change in retinal nerve fiber layer (RNFL) thickness and mean deviation (MD) were measured using linear regression. For each measured rate, simulated measurements of RNFL thickness and MD were generated using the distributions of residuals. Simulated rates of change for different numbers of OCT scans and VF tests over a 2-year period were used to estimate the accuracy of detecting moderate (75th percentile) and rapid (90th percentile) worsening for OCT and VF. Accuracy was defined as the percentage of simulated eyes in which the true rate of worsening (the rate without measurement error) was at or less than a criterion rate (e.g., 75th or 90th percentile).

MAIN OUTCOME MEASURES

The accuracy of diagnosing moderate and rapid rates of glaucoma worsening for different numbers of OCT scans and VF tests over a 2-year period.

RESULTS

Accuracy was less than 50% for both OCT and VF when diagnosing worsening after a 2-year period. OCT accuracy was 5 to 10 percentage points higher than VF accuracy at detecting moderate worsening and 10 to 15 percentage points higher for rapid worsening. Accuracy increased by more than 17 percentage points when using both OCT and VF to detect worsening, that is, when relying on either OCT or VF to be accurate.

CONCLUSIONS

More frequent OCT scans and VF tests are needed to improve the accuracy of diagnosing glaucoma worsening. Accuracy greatly increases when relying on both OCT and VF to detect worsening.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Evidence-Based Guidelines for the Number of Peripapillary OCT Scans Needed to Detect Glaucoma Worsening

PURPOSE

To estimate the number of OCT scans necessary to detect moderate and rapid rates of retinal nerve fiber layer (RNFL) thickness worsening at different levels of accuracy using a large sample of glaucoma and glaucoma-suspect eyes.

DESIGN

Descriptive and simulation study.

PARTICIPANTS

Twelve thousand one hundred fifty eyes from 7392 adult patients with glaucoma or glaucoma-suspect status followed up at the Wilmer Eye Institute from 2013 through 2021. All eyes had at least 5 measurements of RNFL thickness on the Cirrus OCT (Carl Zeiss Meditec) with signal strength of 6 or more.

METHODS

Rates of RNFL worsening for average RNFL thickness and for the 4 quadrants were measured using linear regression. Simulations were used to estimate the accuracy of detecting worsening-defined as the percentage of patients in whom the true rate of RNFL worsening was at or less than different criterion rates of worsening when the OCT-measured rate was also at or less than these criterion rates-for two different measurement strategies: evenly spaced (equal time intervals between measurements) and clustered (approximately half the measurements at each end point of the period).

MAIN OUTCOME MEASURES

The 75th percentile (moderate) and 90th percentile (rapid) rates of RNFL worsening for average RNFL thickness and the accuracy of diagnosing worsening at these moderate and rapid rates.

RESULTS

The 75th and 90th percentile rates of worsening for average RNFL thickness were -1.09 μm/year and -2.35 μm/year, respectively. Simulations showed that, for the average measurement frequency in our sample of approximately 3 OCT scans over a 2-year period, moderate and rapid RNFL worsening were diagnosed accurately only 47% and 40% of the time, respectively. Estimates for the number of OCT scans needed to achieve a range of accuracy levels are provided. For example, 60% accuracy requires 7 measurements to detect both moderate and rapid worsening within a 2-year period if the more efficient clustered measurement strategy is used.

CONCLUSIONS

To diagnose RNFL worsening more accurately, the number of OCT scans must be increased compared with current clinical practice. A clustered measurement strategy reduces the number of scans required compared with evenly spacing measurements.

Effectiveness of Netarsudil versus Brimonidine in Eyes already Being Treated with Glaucoma Medications at a Single Academic Tertiary Care Practice: A Comparative Study

Background

Rho kinase inhibitors, such as netarsudil, are a relatively new class of medications recently introduced into the market for the treatment of glaucoma, the leading cause of irreversible blindness in the world. Previous clinical trials have studied netarsudil's efficacy when used as a first- or second-line agent but limited studies have investigated its effectiveness in the real world where it is more commonly used as a third, fourth, or fifth agent in combination with other topical medications. Equally important, prior studies have not compared its effectiveness to its peer medications in these settings.

Objective

To compare intraocular pressure (IOP) lowering after initiation of netarsudil or brimonidine therapy in patients with glaucoma using >2 medications for IOP management.

Methods

A chart review of 369 eyes from 279 patients followed at a single academic tertiary practice was performed with an institutional review board waiver of consent to compare IOP lowering after prescription of netarsudil (n = 176) versus brimonidine (n = 193) as a third, fourth, or fifth IOP-lowering agent. Patients were identified by querying the electronic medical record for those with a glaucoma-related diagnosis who were prescribed either medication. Five sequential IOP measurements were obtained to determine the mean change in IOP before and after treatment (ΔIOP = mean IOP_4,5 - mean IOP_1,2,3). A multilevel linear mixed-effects model assessed the influence of medication (independent variable) on ΔIOP (dependent variable). Additional independent variables of interest included the number of glaucoma medications at baseline, age, sex, glaucoma type and severity, race, and pretreatment IOP. Bootstrap analysis was performed to remove sampling bias and confirm mixed-effects model findings. Kaplan-Meier survival analysis evaluated the probability of requiring additional intervention within 3 years following the date of medication prescription.

Results

The unadjusted mean (SD) ΔIOP for netarsudil and brimonidine was -2.20 (4.11) mm Hg and -2.21 (3.25) mm Hg, respectively (P = 0.484). The adjusted linear mixed-effects models and bootstrap analysis demonstrated that there was no statistical difference in IOP-lowering effectiveness between the medications. Netarsudil and brimonidine failed to adequately control IOP at similar rates with 42% and 47% probabilities of survival respectively by the 3-year follow-up (P = 0.520).

Conclusions

When escalating pharmacologic therapy, the IOP-lowering effect of netarsudil appeared to be similar to that produced by brimonidine. (Curr Ther Res Clin Exp. 2023; 84:XXX-XXX).

Improving Visual Field Forecasting by Correcting for the Effects of Poor Visual Field Reliability

Purpose

The purpose of this study was to accurately forecast future reliable visual field (VF) mean deviation (MD) values by correcting for poor reliability.

Methods

Four linear regression techniques (standard, unfiltered, corrected, and weighted) were fit to VF data from 5939 eyes with a final reliable VF. For each eye, all VFs, except the final one, were used to fit the models. Then, the difference between the final VF MD value and each model's estimate for the final VF MD value was used to calculate model error. We aggregated the error for each model across all eyes to compare model performance. The results were further broken down into eye-level reliability subgroups to track performance as reliability levels fluctuate.

Results

The standard method, used in the Humphrey Field Analyzer (HFA), was the worst performing model with an average residual that was 0.69 dB higher than the average from the unfiltered method, and 0.79 dB higher than that of the weighted and corrected methods. The weighted method was the best performing model, beating the standard model by as much as 1.75 dB in the 40% to 50% eye-level reliability subgroup. However, its average 95% prediction interval was relatively large at 7.67 dB.

Conclusions

Including all VFs in the trend estimation has more predictive power for future reliable VFs than excluding unreliable VFs. Correcting for VF reliability further improves model accuracy.

Translational Relevance

The VF correction methods described in this paper may allow clinicians to catch VF worsening at an earlier stage.

Differences in visual field loss pattern when transitioning from SITA standard to SITA faster

Swedish Interactive Threshold Algorithm (SITA) Faster is the most recent and fastest testing algorithm for the evaluation of Humphrey visual fields (VF). However, existing evidence suggests that there are some differences in global measures of VF loss in eyes transitioning from SITA Standard to the newer SITA Faster. These differences may be relevant, especially in glaucoma, where VF changes over time influence clinical decisions around treatment. Furthermore, characterization of differences in localizable VF loss patterns between algorithms, rather than global summary measures, can be important for clinician interpretation when transitioning testing strategies. In this study, we determined the effect of transitioning from SITA Standard to SITA Faster on VF loss patterns in glaucomatous eyes undergoing longitudinal VF testing in a real-world clinical setting. Archetypal analysis was used to derive composition weights of 16 clinically relevant VF patterns (i.e., archetypes (AT)) from patient VFs. We found switching from SITA Standard to SITA Faster was associated with less preservation of VF loss (i.e., abnormal AT 2-4, 6-9, 11, 13, 14) relative to successive SITA Standard exams (P value < 0.01) and was associated with relatively greater preservation of AT 1, the normal VF (P value < 0.01). Eyes that transition from SITA Standard to SITA Faster in a real-world clinical setting have an increased likelihood of preserving patterns reflecting a normal VF and lower tendency to preserve patterns reflecting abnormal VF as compared to consecutive SITA Standard exams in the same eye.

Reliability of Several Glaucoma Tests in Patients With Boston Type 1 Keratoprosthesis

PURPOSE

Managing glaucoma after Boston type 1 keratoprosthesis (KPro) surgery remains challenging. We herein assessed the fitness of commonly used clinical tests to evaluate glaucoma in KPro eyes versus eyes with penetrating keratoplasty (PK) as controls.

METHODS

Sixteen patients with KPro and 14 patients with PK tested in an identical manner. After the 10-2 visual field with size V stimulus, intraocular pressure (IOP) was estimated with palpation by the first observer. Then, retinal nerve fiber layer (RNFL) thickness analysis was performed twice using optical coherence tomography by an ophthalmic photographer, before and after a short break. After the second observer estimated the IOP, the visual field was repeated. Finally, color photographs of the optic disk were captured by an ophthalmic photographer. The cup-to-disk ratio was assessed by 2 masked observers, at 2 different time points, in a random manner. Agreements between and within observers and reliability of repeated measurements were evaluated using the intraclass correlation coefficient (ICC) and Bland-Altman plots.

RESULTS

Inter-rater agreement of palpation IOP estimate was moderate for eyes with KPro (ICC = 0.47) and fair for eyes with PK (ICC = 0.27). Visual field and RNFL thickness showed high test-retest reliability in both KPro and PK eyes (ICC > 0.80 for both). Inter-rater agreement of cup-to-disk ratio assessments was substantial in eyes with both KPro (ICC = 0.62) and PK (ICC = 0.70).

CONCLUSIONS

The 10-2 visual field and RNFL thickness seem sufficiently repeatable and might allow the detection of glaucoma progression in KPro eyes. Such testing is important, given limited inter-rater agreement regarding the palpation IOP estimate.

The Effect of Achieving Target Intraocular Pressure on Visual Field Worsening

PURPOSE

To estimate the effect of achieving target intraocular pressure (IOP) values on visual field (VF) worsening in a treated clinical population.

DESIGN

Retrospective analysis of longitudinal data.

PARTICIPANTS

A total of 2852 eyes of 1688 patients with glaucoma-related diagnoses treated in a tertiary care practice. All included eyes had at least 5 reliable VF tests and 5 IOP measures on separate visits along with at least 1 target IOP defined by a clinician on the first or second visit.

METHODS

The primary dependent variable was the slope of the mean deviation (MD) over time (decibels [dB]/year). The primary independent variable was mean target difference (measured IOP - target IOP). We created simple linear regression models and mixed-effects linear models to study the relationship between MD slope and mean target difference for individual eyes. In the mixed-effects models, we included an interaction term to account for disease severity (mild/suspect, moderate, or advanced) and a spline term to account for the differing effects of achieving target IOP (target difference ≤0) and failing to achieve target IOP (target difference >0).

MAIN OUTCOME MEASURES

Rate of change in MD slope (changes in dB/year) per 1 mmHg change in target difference at different stages of glaucoma severity.

RESULTS

Across all eyes, a simple linear regression model demonstrated that a 1 mmHg increase in target difference had a -0.018 dB/year (confidence interval [CI], -0.026 to -0.011; P < 0.05) effect on MD slope. The mixed-effects model shows that eyes with moderate disease that fail to achieve their target IOP experience the largest effects, with a 1 mmHg increase in target difference resulting in a -0.119 dB/year (CI, -0.168 to -0.070; P < 0.05) worse MD slope. The effects of missing target IOP on VF worsening were more pronounced than the effect of absolute level of IOP on VF worsening, where a 1 mmHg increase in IOP had a -0.004 dB/year (CI, -0.011 to 0.003; P > 0.05) effect on the MD slope.

CONCLUSIONS

In treated patients, failing to achieve target IOP was associated with more rapid VF worsening. Eyes with moderate glaucoma experienced the greatest VF worsening from failing to achieve target IOP.

The Association Between Intraocular Pressure and Visual Field Worsening in Treated Glaucoma Patients

PRECIS

In treated eyes with mild/suspect glaucoma, intraocular pressure (IOP) increments are associated with worsening mean deviation (MD) once IOP reaches the 20s. In moderate/advanced eyes, IOP increments are associated with worse visual field (VF) performance across the entire IOP range.

PURPOSE

The purpose of this study was to describe the relationship between mean treated IOP and VF worsening and understand how this relationship is affected by glaucoma severity and IOP range.

METHODS

A total of 1446 eyes of 869 treated glaucoma patients with at least 5 longitudinal reliable VF tests and IOP measures were included. Mixed-effects linear models were employed to understand the effect of eye-specific mean treated IOP on MD slope. Models included interaction terms to assess the differing relationships between MD slope and mean IOP by glaucoma severity (suspect/mild vs. moderate/advanced) and splines to account for the differing effects of mean IOP on MD slope at different IOP ranges (above or below 21 mm Hg).

RESULTS

In suspect/mild glaucoma, when treated IOP values were <21 mm Hg, a 1 mm Hg increment in IOP was not associated with an increase in the rate of VF worsening (P>0.05) but when treated IOP values rose >21 mm Hg, a 1 mm Hg increment in IOP was associated with faster VF worsening (-0.09 dB/y per 1 mm Hg increment, P<0.05). In moderate/advanced disease, a 1 mm Hg increment in treated IOP was associated with faster VF worsening both below and above 21 mm Hg, but the effect was much more pronounced in the higher range (-0.02 dB/y per mm Hg increment <21 mm Hg vs. -0.74 dB/y per mm Hg increment >21 mm Hg, P<0.05 for both).

CONCLUSION

IOP remained associated with VF worsening in eyes with more advanced glaucoma throughout the IOP range but was only associated with VF worsening in eyes with less severe glaucoma at higher IOP.

The Effect of Transitioning from SITA Standard to SITA Faster on Visual Field Performance

PURPOSE

To determine the effect of transitioning from Swedish Interactive Thresholding Algorithm (SITA) Standard to SITA Faster on visual field (VF) performance in glaucomatous eyes with a broad spectrum of disease severity undergoing longitudinal VF testing in a real-world clinical setting.

DESIGN

Retrospective, longitudinal study.

PARTICIPANTS

A total of 421 patients (766 eyes) with manifest or suspect glaucoma followed at a single institution.

METHODS

Each included eye received the following sequence of VF examinations during routine clinical care: (1) SITA Standard, (2) SITA Standard, and (3) SITA Faster (mean time between tests = 13.9 months). Intra-eye comparisons were made between the first 2 VFs (Standard-Standard sequence) and the last 2 VFs (Standard-Faster sequence). The primary dependent variable was the difference in mean deviation (MD) between the second and first VF of the sequence (ΔMD, calculated as MD_VF2 - MD_VF1). The primary independent variable was the VF sequence (Standard-Standard or Standard-Faster). Linear mixed-effects models were used to study the effect of testing sequence on ΔMD, adjusting for confounders including time between VFs and change in false-positive (FP) errors. Results were stratified to understand the effect of glaucoma severity on the relationship between testing sequence and ΔMD.

MAIN OUTCOME MEASURES

The difference in ΔMD between Standard-Standard and Standard-Faster sequence by mild, moderate, and advanced disease severity.

RESULTS

In eyes with mild or suspect glaucoma, there was no significant difference in ΔMD between Standard-Faster and Standard-Standard sequences (-0.23 decibels [dB]; 95% confidence interval [CI], -0.60 to 0.15 dB). However, the Standard-Faster sequence was associated with a 0.87 dB (95% CI, 0.18-1.57 dB) improvement in ΔMD compared with the Standard-Standard sequence in eyes with moderate glaucoma and a 1.49 dB (95% CI, 0.79-2.19 dB) improvement in ΔMD in eyes with advanced glaucoma.

CONCLUSIONS

Converting to SITA Faster in eyes that were previously followed with SITA Standard led to similar VF performance in mild glaucoma but resulted in higher MD values in moderate and advanced glaucoma. For patients with moderate or severe glaucoma, this may conceal disease progression when transitioning testing strategies.

Comparison of Clinical Outcomes with Open Versus Closed Conjunctiva Implantation of the XEN45 Gel Stent

Purpose:

To describe the efficacy and safety of open versus closed conjunctival implantation of the XEN45 Gel Stent (Allergan Inc).

Design:

Retrospective, multicenter study.

Participants:

A total of 137 patients with glaucoma who underwent XEN45 implantation via open or closed conjunctival methods. The XEN45 was implanted as a stand-alone procedure or at the time of cataract surgery by 5 surgeons.

Methods:

Patient demographics, diagnoses, preoperative and postoperative clinical data, outcome measures including intraocular pressure (IOP), use of glaucoma medications, visual acuity, and complications were collected. Statistical analyses were performed with P < 0.05 as significant.

Main Outcome Measures:

Failure was defined as less than 20% reduction of IOP from medicated baseline or IOP >21 mmHg at 2 consecutive visits at postoperative month 1 and beyond, the need for subsequent operative intervention or additional glaucoma surgery, or a catastrophic event such as loss of light perception. Eyes that had not failed by these criteria and were not on glaucoma medications were considered complete successes. Eyes that had not failed but required glaucoma medications were defined as qualified successes.

Results:

Complete success was achieved in 31% and 56% of the closed and open groups, respectively (P = 0.01). Qualified success was achieved in 53% and 71% of the closed and open groups, respectively (P = 0.06). At postoperative month 12, the open conjunctiva group was using fewer glaucoma medications than the closed group (0.9 vs. 1.8, respectively; P = 0.02). At postoperative month 12, the open group had a significantly greater percentage of IOP reduction compared with the closed group (43.1% vs. 24.8%, respectively; P = 0.02). Postoperative needling rates were higher in the closed group compared with the open group (36.1% vs. 11.8%, P = 0.001).

Conclusions:

Implantation of the XEN45 with opening of the conjunctiva is a safe and efficacious procedure to lower IOP with comparable success rate and lower needling rate compared with the closed conjunctiva technique. Prospective evaluation of the various methods for XEN45 implantation will allow for further comparison.

Factors Predicting a Greater Likelihood of Poor Visual Field Reliability in Glaucoma Patients and Suspects

Purpose

Identify factors predicting worse or better than expected visual field (VF) performance.

Methods

A total of 10,262 VFs from 1538 eyes of 909 subjects with manifest or suspected glaucoma were analyzed. Linear mixed-effects models predicted mean deviation (MD) at each timepoint. Differences between observed and predicted MD (ΔMD) were calculated and logistic regression identified factors predicting lower than expected (ΔMD <-1 dB) or higher than expected (ΔMD >1 dB) sensitivity.

Results

Both higher and lower than expected sensitivity were more likely in VFs with severe compared with mild damage (relative risk [RR] >1.3, P < 0.05). Higher than expected sensitivity was more likely in VFs with moderate damage (RR = 2.57, P < 0.001). False-positive (FP) errors increased the likelihood of higher than expected sensitivity at all disease stages (RR >2.1 per 10% increase, P < 0.001), whereas false-negative (FN) errors increased the likelihood of lower than expected sensitivity in mild and moderate disease (RR >1.19 per 10% increase, P < 0.05). Fixation loss errors slightly increased the likelihood of higher than expected VF sensitivity in moderate and severe disease (RR >1.1 per 10% increase, P < 0.01). Longer test duration increased likelihood of lower than expected sensitivity at all disease stages (RR >1.36 per minute increase, P < 0.001). Lower than expected sensitivity was more likely in late afternoon tests (RR = 1.27, P < 0.01). A total of 26.6% of VFs had higher or lower than expected sensitivity in the absence of FPs, FNs, or fixation losses.

Conclusions

FPs, test duration, and FNs are the primary measures predicting if a VF is likely to be reliable, although tests with normal reliability measures may still be unreliable. Our results help clinicians judge VF reliability and highlight the need to integrate reliability measures with other clinical data when making treatment decisions.

Translational Relevance

This likelihood model derived from a large dataset helps clinicians identify VFs that may either falsely suggest disease progression or mask true worsening, thereby improving the utility of VFs in clinical practice.

Evidence-Based Criteria for Determining Peripapillary OCT Reliability

PURPOSE

To assess the impact of OCT signal strength (SS) and artifact on retinal nerve fiber layer (RNFL) measurement reliability and to understand whether glaucoma severity modifies this relationship.

DESIGN

Retrospective, longitudinal cohort study.

PARTICIPANTS

Two thousand nine hundred ninety-two OCT scans from 474 eyes of 241 patients with glaucoma or glaucoma suspect status.

METHODS

We extracted mean RNFL thickness and SS and manually graded scans for artifact. To analyze the effect of SS and artifact on OCT reliability, we (1) created a multilevel linear model using measured RNFL thickness values and demographic and clinical data to estimate the true (predicted) RNFL thickness, (2) calculated model residuals (ΔRNFL) as our reliability measure, and (3) created a second multilevel linear model with splines and interaction terms that modeled overall and quadrant specific reliability (ΔRNFL) as the outcome, using SS and artifact as predictors.

MAIN OUTCOME MEASURES

Impact of SS and artifact on ΔRNFL.

RESULTS

For SS between 10 and 3, the impact of decreases in SS on OCT reliability is modest (-0.67 to -1.25 ΔRNFL per 1-point decrease in SS; P < 0.05). But at less than 3, changes in SS have a large impact on reliability (-15.70 to -16.34 ΔRNFL per 1-point decrease in SS; P < 0.05). At SS between 10 and 3, decreases in SS tend to have a larger impact on reliability in eyes with severe glaucoma (-1.25 per 1-point decrease in SS; P < 0.05) compared with eyes with mild or moderate glaucoma (-0.67 to -0.75 per 1-point decrease in SS; P < 0.05). The presence of artifact has a significant impact on OCT reliability independent of the effects of SS (-4.76 ΔRNFL; P < 0.05). Artifact affects reliability solely in the quadrant in which it occurs, with artifact in one quadrant showing no impact on ΔRNFL in the opposite quadrant (P > 0.05).

CONCLUSIONS

Signal strength decreases down to 3 have relatively mild impacts on OCT reliability. At less than 3, the impact of further decreases in SS on reliability are substantial. The effect of SS on reliability is greater in severe glaucoma. Artifacts result in a decrease in reliability independent of the effect of SS. We propose evidence-based guidelines to guide physicians on whether to trust the results of an OCT scan.

Fluvoxamine-associated oscillopsia and a role for personalized medication dosing

A 60-year-old woman reported horizontal "shimmering" movement while reading crossword puzzles when using fluvoxamine, bupropion, quetiapine, lithium, and levothyroxine. This visual disturbance, likely oscillopsia, started after the fluvoxamine was added and waned as the fluvoxamine was tapered, disappearing after the drug was discontinued. Genetic testing to explore how the patient metabolizes these medications combined with YouScript® interaction analysis suggest that she may have had abnormally high plasma concentrations of fluvoxamine during this time. Oscillopsia may be a novel dose-dependent side effect of fluvoxamine. Genetic testing combined with YouScript has the potential to discover novel drug side effects, elucidate drug interactions and guide future prescribing decisions.

Geospatial distribution and clustering of Chlamydia trachomatis in communities undergoing mass azithromycin treatment

PURPOSE

We detected spatial clustering of households with Chlamydia trachomatis infection (CI) and active trachoma (AT) in villages undergoing mass treatment with azithromycin (MDA) over time.

METHODS

We obtained global positioning system (GPS) coordinates for all households in four villages in Kongwa District, Tanzania. Every 6 months for a period of 42 months, our team examined all children under 10 for AT, and tested for CI with ocular swabbing and Amplicor. Villages underwent four rounds of annual MDA. We classified households as having ≥1 child with CI (or AT) or having 0 children with CI (or AT). We calculated the difference in the K function between households with and without CI or AT to detect clustering at each time point.

RESULTS

Between 918 and 991 households were included over the 42 months of this analysis. At baseline, 306 households (32.59%) had ≥1 child with CI, which declined to 73 households (7.50%) at 42 months. We observed borderline clustering of households with CI at 12 months after one round of MDA and statistically significant clustering with growing cluster sizes between 18 and 24 months after two rounds of MDA. Clusters diminished in size at 30 months after 3 rounds of MDA. Active trachoma did not cluster at any time point.

CONCLUSIONS

This study demonstrates that CI clusters after multiple rounds of MDA. Clusters of infection may increase in size if the annual antibiotic pressure is removed. The absence of growth after the three rounds suggests the start of control of transmission.

Can we stop mass drug administration prior to 3 annual rounds in communities with low prevalence of trachoma?: PRET Ziada trial results

IMPORTANCE

The World Health Organization recommends at least 3 annual mass drug administrations (MDAs) of azithromycin in places where the prevalence of follicular trachoma (FT) is greater than 10%. However, stopping MDA prior to 3 rounds, if monitoring indicates an absence of infection with Chlamydia trachomatis even if FT persists, may be more cost-effective.

OBJECTIVE

To determine the prevalence of infection in communities randomized to 3 rounds of annual MDAs with azithromycin compared with communities randomized to a stopping rule, where MDA could cease if the infection rate was low. DESIGN A 1:1 community randomized trial comparing usual care with a cessation rule. The Partnership for the Rapid Elimination of Trachoma-Ziada Trial was conducted from February 1, 2010, through September 1, 2011.

SETTING

Sixteen communities in Tanzania with trachoma prevalence rates between 10% and 20%.

PARTICIPANTS

A total of 100 children aged 5 years or younger randomly drawn from each community. Children had to reside in an eligible community, have no ocular condition that prevented trachoma grading or ocular specimen collection, and have a guardian who could provide consent for participation.

INTERVENTIONS

Cessation of MDA with azithromycin if the community had no infection in their sample at 6 months or 18 months.

MAIN OUTCOME MEASURE

The prevalence of C trachomatis at 18 months.

RESULTS

None of the intervention communities met criteria to stop MDA based on the 6-month or 18-month survey; all, as well as the usual care communities, were scheduled for a third MDA round. There was no difference in infection (2.9% vs 4.7%; P = .25) between the usual care and cessation rule communities at 18 months.

CONCLUSIONS AND RELEVANCE

In this setting, communities with low (10%-20%) initial prevalence of active trachoma did not have MDA stopped before 3 annual rounds on the basis of monitoring for infection. Infection with C trachomatis in communities with average trachoma rates at 12% to 13% cannot be eliminated before 3 rounds of MDA with azithromycin.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00792922.

Ocular tolerability and efficacy of intravitreal and subconjunctival injections of sirolimus in patients with non-infectious uveitis: primary 6-month results of the SAVE Study

BACKGROUND

The purpose of this study is to evaluate the ocular tolerability and efficacy of sirolimus administered as subconjunctival or intravitreal injections in patients with non-infectious uveitis. Sirolimus as a Therapeutic Approach for Uveitis (SAVE) is a prospective, randomized, open-label, interventional study. Thirty patients were enrolled and randomized in 1:1 ratio to receive either intravitreal injections of 352 μg sirolimus or subconjunctival injections of 1,320 μg at days 0, 60, and 120, with primary endpoint at month 6.

RESULTS

At month 6, all subjects with active uveitis at baseline showed reduction in vitreous haze of one or more steps. Forty percent of subjects showed reduction of two steps or more of vitreous haze (four in each group), and 60% showed a reduction of one-step vitreous haze (seven in group 1 and five in group 2). Changes in the inflammatory indices were statistically significant (p < 0.05) in both study groups. Thirty percent of patients gained one or more lines of visual acuity, 20% lost one or more lines, and 50% maintained the same visual acuity. There were no statistically significant differences between the two study groups at month 6. No serious adverse events were found to be related to the study drug.

CONCLUSION

Local administration of sirolimus, either intravitreally or subconjunctivally, appears to be safe and tolerable. No drug-related systemic adverse events or serious adverse events were noted. Sirolimus delivered as either an intravitreal or subconjunctival injection has demonstrated bioactivity as an immunomodulatory and corticosteroid-sparing agent in reducing vitreous haze and cells, improving visual acuity, and in decreasing the need for systemic corticosteroids.

The role of biologic agents in the management of non-infectious uveitis

INTRODUCTION

Uveitis is an intriguing group of disorders characterized by inflammation of the uveal tract. Due to the potential grave consequences of the disease process, it is important to assess the various therapeutic options available for treating uveitis, and their outcomes.

AREAS COVERED

This review discusses the use of conventional agents in the management of uveitis, including discussion of the molecular and clinical properties of corticosteroids, antimetabolites, calcineurin inhibitors and alkylating agents and their side effects. In addition, it also discusses the molecular and clinical properties of novel biologic agents and their side effects. Moreover, recommendations as to when biologic agents should be employed are also discussed.

EXPERT OPINION

We recommend that in general (except in selected cases of Adamantiades-Behçet's disease) biologics should not be used as a first-line therapy for uveitis due to inconvenience, high cost, and potential immunosuppressive effects. However, many biologics are potent in inducing drug-free remission of uveitis and may be employed to manage recurrent diseases or diseases not responsive to conventional agents.

Sclerochoroidal calcifications imaged using enhanced depth imaging optical coherence tomography

PURPOSE

To report a case of sclerochoroidal calcifications and describe the appearance of these lesions using optical coherence tomography with enhanced depth imaging (EDI-OCT) technology.

DESIGN

Case Report

METHODS

An 85-year-old patient who presented with bilateral retinal lesions suspected to be metastases was evaluated with slit-lamp biomicroscopy, funduscopy, fluorescein angiography, B-scan ultrasonography (U/S), and EDI-OCT.

RESULTS

B-scan U/S demonstrated echo-dense consolidations in the choroid bilaterally with acoustic shadowing consistent with sclerochoroidal calcifications. EDI-OCT revealed hyper-reflective lesions with decreased reflectivity posterior to the lesion.

CONCLUSIONS

Sclerochoroidal calcifications should be included in the differential of choroidal masses, given their unique appearance on EDI-OCT.

Robotic-assisted versus traditional laparoscopic partial nephrectomy: comparison of outcomes and evaluation of learning curve

OBJECTIVES

To examine the transition to robot-assisted laparoscopic partial nephrectomy (RALPN) from pure laparoscopic partial nephrectomy (LPN) and investigate the learning curve (LC). RALPN has emerged as a minimally invasive alternative to nephron-sparing surgery.

METHODS

A total of 150 consecutive patients were identified who underwent LPN or RALPN in the initial experience of a single surgeon since 2006. The perioperative data were evaluated using appropriate comparative tests. The LC was investigated by examining the operative times, warm ischemia times (WITs), and estimated blood loss (EBL) in groups of 25 consecutive patients. To account for laparoscopic LC, the outcomes of patients who underwent surgery in 2009 or later were also compared.

RESULTS

Of the 150 patients, 102 and 48 underwent LPN and RALPN, respectively. The patient and tumor characteristics were similar. The mean operative time (193 vs 152 minutes, P < .001), WIT (18.0 vs 14.0, P < .001), and EBL (245 vs 122 mL, P = .001) favored RALPN. Improvements in the operative time (P = .01), WIT (P = .006), and EBL (P = .01) were noted as experience increased in the LPN cohort and was most pronounced after the first 25 LPN patients. Since 2009, 55 and 44 patients underwent LPN and RALPN, respectively. Although the absolute differences were less, the operative time (182 vs 150, P < .001), WIT (15.3 vs 13.3, P < .001), and EBL (206 vs 118, P = .005) favored RALPN.

CONCLUSIONS

RALPN appears to have shorter operative and ischemia times and less blood loss compared with LPN. After a LC of approximately 25 cases, the transition from LPN to RALPN can be undertaken without an additional LC and can be associated with immediate benefits.

Retroperitoneal hibernoma in a 28-year-old man

Retroperitoneal hibernomas are rare, with only a handful of cases reported in the literature. These benign lesions are composed primarily of brown fat and can include varying amounts of white fat, myxoid material, and spindled cells, which makes their imaging characteristics highly variable. Here we present a series of images taken in a 28-year-old-man with pathologically confirmed retroperitoneal hibernoma. Surgical excision was undertaken and resulted in complete removal of the lesion.

Microperforations of surgical gloves in urology: minimally invasive versus open surgeries

INTRODUCTION

Surgical glove integrity is important in preventing wound infections and reducing patient mortality. Rates of perforations have been studied in many surgical subspecialties, but glove perforations specific to urology have not been investigated previously. This study aims to determine the incidence of glove perforations during urological surgeries and to investigate differences between open, laparoscopic, and endoscopic procedures.

MATERIALS AND METHODS

A total of 180 gloves were collected from various urological procedures performed at our institution: 59 from endoscopic, 72 from laparoscopic, and 49 from open cases. The gloves were tested for defects by both the water load test and electrical conductance testing. The frequency of defects for each type of procedure along with the length of wear, surgeon experience, and glove brand was analyzed.

RESULTS

Glove defects were detected in 29% of all cases. Microperforations encompassed the majority of the glove defects (23.3%) and were detected in 15.2%, 25.0 %, and 30.6% of the endoscopy, laparoscopic and open surgical cases, respectively. The frequency of perforations noted in the minimally invasive procedures was significantly different across the groups (p < 0.01). There was no statistical significant correlation between glove defects and operation time, surgeon experience, and glove brand.

CONCLUSIONS

The rates of glove perforation (29%) in urological procedures were higher than expected. Given the high rates of glove perforations found, double gloving in urological surgeries may offer a solution to the increased risk for cross contamination from microscopic perforations.

Analysis of tyrosine phosphorylation-dependent interactions between stimulatory effector proteins and the B cell co-receptor CD22

The B cell-restricted transmembrane glycoprotein CD22 is rapidly phosphorylated on tyrosine in response to cross-linking of the B cell antigen receptor, thereby generating phosphotyrosine motifs in the cytoplasmic domain which recruit intracellular effector proteins that contain Src homology 2 domains. By virtue of its interaction with these effector proteins CD22 modulates signal transduction through the B cell antigen receptor. To define further the molecular mechanism by which CD22 mediates its co-receptor function, phosphopeptide mapping experiments were conducted to determine which of the six tyrosine residues in the cytoplasmic domain are involved in recruitment of the stimulatory effector proteins phospholipase Cgamma (PLCgamma), phosphoinositide 3-kinase (PI3K), Grb2, and Syk. The results obtained indicate that the protein tyrosine kinase Syk interacts with multiple CD22-derived phosphopeptides in both immunoprecipitation and reverse Far Western assays. In contrast, the Grb2.Sos complex was observed to bind exclusively to the fourth phosphotyrosine motif (Y828ENV) from CD22 and does so via a direct interaction based on Far Western and reverse Far Western blotting. Although both PLCgamma and PI3K were observed to bind to multiple phosphopeptides in precipitation experiments, subsequent studies using reverse Far Western blot analysis demonstrated that only the carboxyl-terminal phosphopeptide of CD22 (Y863VTL) binds directly to either one. This finding suggests that PLCgamma and PI3K may be recruited to CD22 either through a direct interaction with Tyr863 or indirectly through an association with one or more intermediate proteins.