Characteristics Associated with Adherence to Annual Dilated Eye Examinations among US Patients with Diagnosed Diabetes.

PURPOSE: To identify the characteristics that are associated with adherence to annual diabetic eye exams and patient awareness of retinopathy using a nationally representative sample from the United States. DESIGN: Cross-sectional, secondary analysis. PARTICIPANTS: National Health and Nutrition Examination Survey (NHANES) participants from 2005 to 2016 aged 20 years and older with diabetes mellitus. METHODS: The NHANES collected surveys every 2 years from 2005 to 2016, which contained demographic information, clinical information, and time to last dilated eye exam. From 2005 to 2008, retinal photographs were taken of all participants older than 40 years of age. We used univariate and multivariable logistic regression to determine the demographic and clinical factors associated with adherence to annual diabetic eye examinations and those associated with correctly reporting their retinopathy status. MAIN OUTCOME MEASURE: Factors associated with adherence defined as having an eye exam within the preceding 12 or 24 months. RESULTS: From 2005 to 2016, NHANES surveyed 4072 individuals who represent 20 million Americans aged 20 years and older with self-report of diabetes. By using the adherence definitions of 12 and 24 months, 63.4% and 78.7%, respectively, were adherent to diabetic eye examinations. The nonadherence rates of 36.6% and 21.3% for this national estimate did not change from 2005 to 2016 (P = 0.7, logistic regression). Insurance status, age, education, income, cholesterol levels, duration of diabetes, and self-reported retinopathy were all significantly associated with adherence with both definitions (all P < 0.05, logistic regression). Insurance status had the highest predictive value, with 76% of Americans on combination private-public insurance adherent compared with 36% of uninsured. Most Americans with retinopathy incorrectly denied having the diagnosis (2 727 144/3 896 093 or 70%). CONCLUSIONS: Multiple variables were associated with nonadherence to eye exams, with insurance status having the strongest association. Adherence with annual eye exams has not improved over the past decade. The majority of patients with retinopathy are unaware of this diagnosis, including the majority of those with a dilated funduscopic examination in the past year. Further improvements in education and adherence may reduce the visual morbidity caused by diabetes.

Eye Disease in Patients with Diabetes Screened with Telemedicine.

BACKGROUND: Telemedicine with nonmydriatic cameras can detect not only diabetic retinopathy but also other eye disease. OBJECTIVE: To determine the prevalence of eye diseases detected by telemedicine in a population with a high prevalence of minority and American Indian/Alaskan Native (AI/AN) ethnicities. SUBJECTS AND METHODS: We recruited diabetic patients 18 years and older and used telemedicine with nonmydriatic cameras to detect eye disease. Two trained readers graded the images for diabetic retinopathy, age-related macular degeneration (ARMD), glaucomatous features, macular edema, and other eye disease using a standard protocol. We included both eyes for analysis and excluded images that were too poor to grade. RESULTS: We included 820 eyes from 424 patients with 72.3% nonwhite ethnicity and 50.3% AI/AN heritage. While 283/424 (66.7%) patients had normal eye images, 120/424 (28.3%) had one disease identified; 15/424 (3.5%) had two diseases; and 6/424 (1.4%) had three diseases in one or both eyes. After diabetic retinopathy (104/424, 24.5%), the most common eye diseases were glaucomatous features (44/424, 10.4%) and dry ARMD (24/424, 5.7%). Seventeen percent (72/424, 17.0%) showed eye disease other than diabetic retinopathy. CONCLUSIONS: Telemedicine with nonmydriatic cameras detected diabetic retinopathy, as well as other visually significant eye disease. This suggests that a diabetic retinopathy screening program needs to detect and report other eye disease, including glaucoma and macular disease.

Primary Open-Angle Glaucoma Preferred Practice Pattern(®) Guidelines.

UNLABELLED: PRIMARY OPEN-ANGLE GLAUCOMA PREFERRED PRACTICE PATTERN® GUIDELINES: Evidence-based update of the Primary Open-Angle Glaucoma Preferred Practice Pattern® (PPP) guidelines, describing the diagnosis and management of patients with primary open-angle glaucoma with an algorithm for patient management and detailed recommendations for evaluation and treatment options.

Primary Angle Closure Preferred Practice Pattern(®) Guidelines.

UNLABELLED: PRIMARY ANGLE CLOSURE PREFERRED PRACTICE PATTERN® GUIDELINES: Evidence-based update of the Primary Angle Closure Preferred Practice Pattern® (PPP) guidelines, describing the diagnosis and management of patients with primary angle closure with detailed recommendations for evaluation and treatment options.

Primary Open-Angle Glaucoma Suspect Preferred Practice Pattern(®) Guidelines.

UNLABELLED: PRIMARY OPEN-ANGLE GLAUCOMA SUSPECT PREFERRED PRACTICE PATTERN® GUIDELINES: Evidence-based update of the Primary Open-Angle Suspect Glaucoma Preferred Practice Pattern® (PPP) guidelines, describing the diagnosis and management of patients with primary open-angle glaucoma suspect with detailed recommendations for evaluation and treatment options.

Predictors of adherence to glaucoma treatment in a multisite study.

BACKGROUND: Poor adherence hinders glaucoma treatment. Studies have identified demographic and clinical predictors of adherence but fewer psychological variables. PURPOSE: We examined predictors from four health behavior theories and past research. METHODS: In the baseline phase of a three-site adherence study, before any intervention, 201 participants used electronic Medication Event Monitoring System (MEMS) bottles to monitor eyedrop use for 2 months, and completed questionnaires including self-reported adherence. RESULTS: MEMS showed 79% adherence and self-report 94% (0.5-1.5 missed weekly doses), but they correlated only r(s) = 0.31. Self-efficacy, motivation, dose frequency, and nonminority race/ethnicity predicted 35% of variance in MEMS. Cues to action, self-efficacy, and intention predicted 20% of variance in self-reported adherence. CONCLUSIONS: Self-efficacy, motivation, intention, cues to action, dose frequency, and race/ethnicity each independently predicted adherence. Predictors from all theories were supported in bivariate analyses, but additional study is needed. Researchers and clinicians should consider psychological predictors of adherence. (ClinicalTrials.gov ID# NCT01409421.).

Assessment of the reliability of standard automated perimetry in regions of glaucomatous damage.

PURPOSE: Visual field testing uses high-contrast stimuli in areas of severe visual field loss. However, retinal ganglion cells saturate with high-contrast stimuli, suggesting that the probability of detecting perimetric stimuli may not increase indefinitely as contrast increases. Driven by this concept, this study examines the lower limit of perimetric sensitivity for reliable testing by standard automated perimetry. DESIGN: Evaluation of a diagnostic test. PARTICIPANTS: A total of 34 participants with moderate to severe glaucoma; mean deviation at their last clinic visit averaged -10.90 dB (range, -20.94 to -3.38 dB). A total of 75 of the 136 locations tested had a perimetric sensitivity of ≤ 19 dB. METHODS: Frequency-of-seeing curves were constructed at 4 nonadjacent visual field locations by the Method of Constant Stimuli (MOCS), using 35 stimulus presentations at each of 7 contrasts. Locations were chosen a priori and included at least 2 with glaucomatous damage but a sensitivity of ≥ 6 dB. Cumulative Gaussian curves were fit to the data, first assuming a 5% false-negative rate and subsequently allowing the asymptotic maximum response probability to be a free parameter. MAIN OUTCOME MEASURES: The strength of the relation (R(2)) between perimetric sensitivity (mean of last 2 clinic visits) and MOCS sensitivity (from the experiment) for all locations with perimetric sensitivity within ± 4 dB of each selected value, at 0.5 dB intervals. RESULTS: Bins centered at sensitivities ≥ 19 dB always had R(2) >0.1. All bins centered at sensitivities ≤ 15 dB had R(2) <0.1, an indication that sensitivities are unreliable. No consistent conclusions could be drawn between 15 and 19 dB. At 57 of the 81 locations with perimetric sensitivity <19 dB, including 49 of the 63 locations ≤ 15 dB, the fitted asymptotic maximum response probability was <80%, consistent with the hypothesis of response saturation. At 29 of these locations the asymptotic maximum was <50%, and so contrast sensitivity (50% response rate) is undefined. CONCLUSIONS: Clinical visual field testing may be unreliable when visual field locations have sensitivity below approximately 15 to 19 dB because of a reduction in the asymptotic maximum response probability. Researchers and clinicians may have difficulty detecting worsening sensitivity in these visual field locations, and this difficulty may occur commonly in patients with glaucoma with moderate to severe glaucomatous visual field loss.

Predicting adherence to diabetic eye examinations: development of the compliance withAnnual Diabetic Eye Exams Survey.

OBJECTIVE: To identify variables that predict adherence with annual eye examinations using the Compliance with Annual Diabetic Eye Exams Survey (CADEES), a new questionnaire designed to measure health beliefs related to diabetic retinopathy and annual eye examinations. DESIGN: Questionnaire development. PARTICIPANTS: Three hundred sixteen adults with diabetes. METHODS: We developed the CADEES based on a review of the literature, the framework of the Health Belief Model, expert opinion, and pilot study data. To examine content validity, we analyzed participant responses to an open-ended question asking for reasons why people do not obtain annual eye examinations. We evaluated construct validity with principal components analysis and examined internal consistency with Cronbach's α. To assess predictive validity, we used multivariate logistic regression with self-reported adherence as the dependent variable. MAIN OUTCOME MEASURES: Associations with self-reported adherence (defined as having a dilated eye examination in the past year). RESULTS: The content analysis showed that CADEES items covered 89% of the reasons given by participants for not obtaining an annual eye examination. The principal components analysis identified 3 informative components that made up 32% of the variance. Multivariate logistic regression modeling revealed several significant predictors of adherence, including beliefs concerning whether insurance covered most of the eye examination cost (P < 0.01), whether there were general barriers that make it difficult to obtain an eye examination (P < 0.01), whether obtaining an eye examination was a top priority (P = 0.02), and whether diabetic eye disease can be seen with an examination (P = 0.05). Lower hemoglobin A1c levels (P < 0.01), having insurance (P = 0.01), and a longer duration of diabetes (P = 0.02) also were associated with adherence. A multivariate model containing CADEES items and demographic variables classified cases with 72% accuracy and explained approximately 24% of the variance in adherence. CONCLUSIONS: The CADEES showed good content and predictive validity. Although additional research is needed before finalizing a shorter version of the survey, our findings suggest that researchers and clinicians may be able to improve adherence by (1) counseling newly diagnosed patients, as well as those with uncontrolled blood glucose, on the importance of annual eye examinations and (2) discussing perceived barriers and misconceptions.

OCT Segmentation Errors with Bruch's Membrane Opening-Minimum Rim Width as Compared with Retinal Nerve Fiber Layer Thickness.

OBJECTIVE: To compare the magnitude and location of automated segmentation errors of the Bruch's membrane opening-minimum rim width (BMO-MRW) and retinal nerve fiber layer thickness (RNFLT). DESIGN: Cross-sectional study. PARTICIPANTS: We included 162 glaucoma suspect or open-angle glaucoma eyes from 162 participants. METHODS: We used spectral-domain optic coherence tomography (Spectralis 870 nm, Heidelberg Engineering) to image the optic nerve with 24 radial optic nerve head B-scans and a 12-degree peripapillary circle scan, and exported the native "automated segmentation only" results for BMO-MRW and RNFLT. We also exported the results after "manual refinement" of the measurements. MAIN OUTCOME MEASURES: We calculated the absolute and proportional error globally and within the 12 30-degree sectors of the optic disc. We determined whether the glaucoma classifications were different between BMO-MRW and RNFLT as a result of manual and automatic segmentation. RESULTS: The absolute error mean was larger for BMO-MRW than for RNFLT (10.8 µm vs. 3.58 µm, P < 0.001). However, the proportional errors were similar (4.3% vs. 4.4%, P = 0.47). In a multivariable regression model, errors in BMO-MRW were not significantly associated with age, location, magnitude, or severity of glaucoma loss (all P ≥ 0.05). However, larger RNFLT errors were associated with the superior and inferior sector location, thicker nerve fiber layer, and worse visual field (all P < 0.05). Errors in BMO-MRW and RNFLT were not likely to occur in the same sector location (R2 = 0.001; P = 0.15). With manual refinement, the glaucoma classification changed in 7.8% and 6.2% of eyes with BMO-MRW and RNFLT, respectively. CONCLUSIONS: Both BMO-MRW and RNFLT measurements included segmentation errors, which did not seem to have a common location, and may result in differences in glaucoma classification. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

The association between glaucoma treatment adherence with disease progression and loss to follow-up.

Prospective cohort study from Brazil to evaluate glaucoma treatment adherence using a medication event monitoring system (MEMS) device and correlate with glaucoma progression and loss to follow-up (LTF) after one year of follow up. We included primary open glaucoma (POAG) patients treated with at least one ocular hypotensive eye drop. MEMS devices was used to monitor adherence for 60 days and evaluate the percentage of doses prescribed taken within the 60-day period. We classified patients according to rates of adherence: low adherence (less than 75% from MEMS measurements) and high adherence (more than 75% from MEMS measurements). We applied a questionnaire to investigated self-reported behavior towards treatment behaviors (glaucoma treatment compliance assessment tool, GTCAT). We also correlated rates of treatment adherence with clinical, demographical variables and the occurrence of glaucoma progression or LTF after one year of observation. We included 110 POAG patients and found that 28.18% of them were considered low adherent. We identify several variables associated with poor adherence such as glaucoma progression, LTF, younger age, low educational and income levels, absence of health insurance, years of disease and peak intraocular pressure. Several constructs from the self-reported GTCAT were also correlated with the rates of treatment adherence. To date, this is the first study in Latin America to evaluate glaucoma treatment adherence with MEMS devices and correlate adherence rates with glaucoma progression and LTF. We found a low-adherence rate of 28.18% and several additional risk factors were statistically associated with poor adherence.

Comparing the effectiveness of telemedicine and traditional surveillance in providing diabetic retinopathy screening examinations: a randomized controlled trial.

OBJECTIVE: To determine the effectiveness of telemedicine for providing diabetic retinopathy screening examinations compared with the effectiveness of traditional surveillance in community health clinics with a high proportion of minorities, including American Indian/Alaska Natives. SUBJECTS AND METHODS: We conducted a multicenter, randomized controlled trial and assigned diabetic participants to one of two groups: (1) telemedicine with a nonmydriatic camera or (2) traditional surveillance with an eye care provider. For those receiving telemedicine, the criteria for requiring follow-up with an eye care provider were (1) moderate nonproliferative diabetic retinopathy or higher, (2) presence of clinically significant macular edema, or (3) "unable to grade" result for diabetic retinopathy or macular edema. RESULTS: The telemedicine group (n=296) was more likely to receive a diabetic retinopathy screening examination within the first year of enrollment compared with the traditional surveillance group (n=271) (94% versus 56%, p<0.001). The overall prevalence of diabetic retinopathy at baseline was 21.4%, and macular edema was present in 1.4% of participants. In the telemedicine group, 20.5% would require further evaluation with an eye care provider, and 86% of these referrals were because of poor-quality digital images. CONCLUSIONS: Telemedicine using nonmydriatic cameras increased the proportion of participants who obtained diabetic retinopathy screening examinations, and most did not require follow-up with an eye care provider. Telemedicine may be a more effective way to screen patients for diabetic retinopathy and to triage further evaluation with an eye care provider. Methods to decrease poor quality imaging would improve the effectiveness of telemedicine for diabetic retinopathy screening examinations.

Detectability of Visual Field Defects in Glaucoma Using Moving Versus Static Stimuli for Perimetry.

Purpose: We have previously shown that using moving, instead of static, stimuli extends the effective dynamic range of automated perimetry in glaucoma. In this study, we further investigate the effect of using moving stimuli on the detectability of functional loss. Methods: We used two experimental perimetry paradigms to test 155 subjects with a diagnosis of glaucoma or glaucoma suspect, and 34 healthy control subjects. One test used stimuli moving parallel to the average nerve fiber bundle orientation at each location; the other used static stimuli. Algorithms were otherwise identical. Sensitivities to moving stimuli were transformed to the equivalent values for static stimuli based on a Bland-Altman plot. The proportions of locations outside age-corrected normative limits were compared, and test-retest variability was compared against defect depth for each stimulus type. Results: More tested locations were below the fifth percentile of the normative range for that location using static stimuli. However, among locations abnormal according to standard clinical perimetry on the same day, 19.2% were abnormal using static stimuli, versus 20.5% using moving stimuli (P = 0.372). Test-retest variability was 44% lower for moving stimuli across the range of defect depths. Conclusions: When compared with static automated perimetry and expressed on a common scale, moving stimuli extend the effective dynamic range and decrease variability, without decreasing the detectability of known functional defects. Translational Relevance: Moving stimuli provide a method to improve known problems of current clinical perimetry.

Patients with Low Vision Struggle with Placing Eye Drops and Benefit from an Eye Drop Aid.

PURPOSE: To evaluate eye drop self-administration in a low-vision patient population and test whether a nose-pivoted drop delivery device (NPDD, GentleDrop) can improve eye drop delivery in these patients. DESIGN: Repeated-measures case series. PARTICIPANTS: Thirty subjects (58 eyes) with low vision, defined as best-corrected visual acuity worse than 20/60 or visual field worse than 20° in the better-seeing eye. METHODS: We video-recorded subjects while self-administering eye drops using their own traditional delivery at baseline, after a standardized teaching, and with an NPDD. Two masked graders independently reviewed each drop delivery. Primary success was defined as the drop reaching the eye without the bottle touching the eye or eyelids. Subjects rated ease-of-use (1-10 scale, 10 = easiest) after each drop delivery and completed a satisfaction survey, which included asking whether subjects could place drops independently (1-5 scale, 5 = most independent). MAIN OUTCOME MEASURES: Logistic-transformed generalized estimating equation regression to compare technique satisfaction, ease-of-use, independence, no contact, and success. RESULTS: Primary success was observed in 30 (52%) of 58 eyes at baseline and increased to 44 eyes (76%) with an NPDD (P = 0.013). Bottle tip contact occurred in 23 (40%) of 58 eyes at baseline and 8 eyes (14%) with an NPDD (P = 0.004). Mean ease-of-use scores were 6.7 ± 3.1 at baseline and 8.3 ± 1.8 (P < 0.001) with an NPDD. Likewise, the NPDD improved success, bottle tip contact, and ease-of-use compared with post-teaching traditional delivery (P < 0.01). Twenty-two (73%) of 30 subjects preferred the NPDD to traditional delivery. Twenty-nine (97%) thought the NPDD was comfortable to use, and all would recommend the device. A subgroup analysis was performed on 16 subjects that self-reported difficulty instilling drops at baseline. The NPDD showed similar results, and it increased confidence in placing drops independently (4.6 ± 0.9) compared with baseline (2.7 ± 1.6, P < 0.001). Fifteen (94%) subjects in this subgroup preferred the NPDD. CONCLUSIONS: Low-vision subjects struggled to self-administer eye drops. An NPDD can improve bottle tip contact, ease-of-use, satisfaction, and independence. Eye care providers could consider screening low-vision patients about difficulty with eye drop self-administration and recommending eye drop aids. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Eye Drop Adherence With an Eye Drop Bottle Cap Monitor.

PRCIS: An eye drop bottle cap monitor with audio and visual alarms measured eye drop adherence in 50 subjects with glaucoma. Baseline adherence rates were too high to test if the alarms could improve adherence. PURPOSE: To determine if an eye drop bottle cap monitor can measure and improve adherence. MATERIALS AND METHODS: The Devers Drop Device (D3, Universal Adherence LLC) was designed to measure eye drop adherence by detecting bottle cap removal and replacement, and it can provide text, visual and audio alerts when a medication is due. In Stage 1, we determined baseline adherence for 50 subjects using a nightly eye drop over a 25-day period. Subjects with less than 90% baseline adherence were eligible for Stage 2. In Stage 2, we randomized subjects to receive either no reminder or automated D3 alerts for their nightly eye drop over a subsequent 25-day period. We defined adherence as the proportion of drops administered within 3 hours of the subjects' scheduled dosing time. Subjects completed 3 questions regarding satisfaction with the device and willingness to pay. RESULTS: The D3 monitor remained attached to the eye drop bottle cap for the duration of the study and collected adherence data in all 50 patients. In Stage 1, the mean adherence rate was 90 ± 18% (range 32-100%). Forty (80%) subjects had an adherence rate greater than 90%. Adherence rates were too high in Stage 1 to adequately test the effects of reminders in Stage 2. Ninety-eight percent (49/50) and 96% (48/50) of subjects agreed "the device always stayed attached to the bottle cap" and "I was able to use the device to take the drops", respectively. Patients would pay $61±83 (range $0-400) for a similar device to improve adherence. CONCLUSIONS: The D3 can measure eye drop adherence. Research subjects reported high satisfaction and willingness to pay for an eye drop bottle cap monitor. Glaucoma patients have high adherence when they are being monitored, and future studies with research subjects screened for poor adherence may further determine the benefit of electronic monitoring of adherence with and without electronic reminders.

Reduction in intraocular pressure after cataract extraction: the Ocular Hypertension Treatment Study.

PURPOSE: To determine the change in intraocular pressure (IOP) after cataract extraction in the observation group of the Ocular Hypertension Treatment Study. DESIGN: Comparative case series. PARTICIPANTS: Forty-two participants (63 eyes) who underwent cataract surgery in at least 1 eye during the study and a control group of 743 participants (743 eyes) who did not undergo cataract surgery. METHODS: We defined the "split date" as the study visit date at which cataract surgery was reported in the cataract surgery group and a corresponding date in the control group. Preoperative IOP was defined as the mean IOP of up to 3 visits before the split date. Postoperative IOP was the mean IOP of up to 3 visits including the split date (0, 6, and 12 months' with "0 months" equaling the split date). In both groups, we censored data after initiation of ocular hypotensive medication or glaucoma surgery of any kind. MAIN OUTCOME MEASURES: Difference in preoperative and postoperative IOP. RESULTS: In the cataract group, postoperative IOP was significantly lower than the preoperative IOP (19.8 ± 3.2 mmHg vs. 23.9 ± 3.2 mmHg; P<0.001). The postoperative IOP remained lower than the preoperative IOP for at least 36 months. The average decrease in postoperative IOP from preoperative IOP was 16.5%, and 39.7% of eyes had postoperative IOP ≥ 20% below preoperative IOP. A greater reduction in postoperative IOP occurred in the eyes with the highest preoperative IOP. In the control group, the corresponding mean IOPs were 23.8 ± 3.6 before the split date and 23.4 ± 3.9 after the split date. CONCLUSIONS: Cataract surgery decreases IOP in patients with ocular hypertension over a long period of time.

Moving Stimulus Perimetry: A New Functional Test for Glaucoma.

Purpose: Static pointwise perimetric sensitivities of less than approximately 19 dB are unreliable in glaucoma owing to excessive variability. We propose using moving stimuli to increase detectability, decrease variability, and hence increase this dynamic range. Methods: A moving stimulus was designed to travel parallel to the average nerve fiber bundle orientation at each location, and compared against an otherwise identical static stimulus. To assess dynamic range, psychometric functions were measured at 4 locations of each of 10 subjects. To assess clinically realistic test-retest variability, 34 locations of 94 subjects with glaucoma and glaucoma suspects were tested twice, 6 months apart. Pointwise sensitivity estimates were compared using generalized estimating equation regression models. The test-retest limits of agreement for each stimulus were assessed, adjusted for within-eye clustering. Results: Using static stimuli, 9 of the 40 psychometric functions had less than a 90% maximum response probability, suggesting being beyond the dynamic range. Eight of those locations had asymptotic maximum of more than 90% with moving stimuli. Sensitivities were higher for moving stimuli (P < 0.001); the difference increased as sensitivity decreased (P < 0.001). Test-retest limits of agreement were narrower for moving stimuli (-6.35 to +6.48 dB) than static stimuli (-12.7 to +7.81 dB). Sixty-two percent of subjects preferred using moving stimuli versus 19% who preferred static stimuli. Conclusions: Using a moving stimulus increases perimetric sensitivities in regions of glaucomatous loss. This extends the effective dynamic range, allowing reliable testing later into the disease. Results are more repeatable, and the test is preferred by most subjects. Translational Relevance: Moving stimuli allow reliable testing in patients with more severe glaucoma than currently possible.

Long- and Short-Term Variability of Perimetry in Glaucoma.

Purpose: Test-retest variability in perimetry consists of short-term and long-term components, both of which impede assessment of progression. By minimizing and quantifying the algorithm-dependent short-term variability, we can quantify the algorithm-independent long-term variability that reflects true fluctuations in sensitivity between visits. We do this at locations with sensitivity both < 28 dB (when the stimulus is smaller than Ricco's area and complete spatial summation can be assumed) and > 28 dB (when partial summation occurs). Methods: Frequency-of-seeing curves were measured at four locations of 35 participants with glaucoma. The standard deviation of cumulative Gaussian fits to those curves was modeled for a given sensitivity and used to simulate the expected short-term variability of a 30-presentation algorithm. A separate group of 137 participants was tested twice with that algorithm, 6 months apart. Long-term variance at different sensitivities was calculated as the LOESS fit of observed test-retest variance minus the LOESS fit of simulated short-term variance. Results: Below 28 dB, short-term variability increased approximately linearly with increasing loss. Long-term variability also increased with damage below this point, attaining a maximum standard deviation of 2.4 dB at sensitivity 21 dB, before decreasing due to the floor effect of the algorithm. Above 30 dB, the observed test-retest variance was slightly smaller than the simulated short-term variance. Conclusions: Long-term and short-term variability both increase with damage for perimetric stimuli smaller than Ricco's area. Above 28 dB, long-term variability constitutes a negligible proportion of test-retest variability. Translational Relevance: Fluctuations in true sensitivity increase in glaucoma, even after accounting for increased short-term variability. This long-term variability cannot be reduced by altering testing algorithms alone.