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On-Call Examinations for Acute Onset of Flashes, Floaters, or Curtain by Junior Ophthalmology Residents

Outcomes, Safety, and Resource Use
Published:August 11, 2020DOI:https://doi.org/10.1016/j.oret.2020.07.030

      Purpose

      To determine whether an on-call system serviced by junior residents can safely triage patients with symptoms concerning for posterior vitreous detachment, retinal tear, and retinal detachment.

      Design

      Quality improvement study structured as a prospective cohort study.

      Participants

      All symptomatic patients seen in 2017 by an on-call junior resident were followed up (257 patients). Those with follow-up within 6 months of initial presentation (228 patients, 246 unique encounters) were included.

      Methods

      We prospectively tracked all symptomatic patients seen on-call by a junior resident in 2017 at a major academic medical center.

      Main Outcome Measures

      Incidence and predictors of true retinal tears or detachments, false-positive tears or detachments, false-negative tears or detachments, and resource use.

      Results

      Of 246 symptomatic encounters, 83 (33.7%) had a perceived retinal tear or detachment. Residents used B-scan ultrasonography in a high number of encounters (41.0%). Ten (4.1%) false-positive tears or detachments were identified, with the presence of intraretinal hemmorhage predicting a false-positive examination (adjusted odds ratio, 3.86; 95% confidence interval, 1.1–13.5). Thirteen (5.3%) false-negative tears and no false-negative detachments were identified. Eleven (84.6%) false-negative tears underwent follow-up within days based on high-risk characteristics, and no false-negative tears progressed to detachment at follow-up. Measures of resource use included an in-person confirmation of examination findings by the senior resident or fellow in 59 encounters (24.0%) and shorter follow-up times to a retina rather than a nonretina clinic for 52 of 151 patients who showed no pathologic features on initial examination.

      Conclusions

      Junior residents can safely provide on-call triage of patients with symptoms concerning for a posterior vitreous detachment, retinal tear, or retinal detachment. The system requires moderate resource use, including occasional confirmatory examinations by a second physician and shorter follow-up times to retina clinic for high-risk patients.

      Keywords

      Abbreviations and Acronyms:

      FFCBV (flashes, floaters, curtain, or blurred vision), heme (hemorrhage), PVD (posterior vitreous detachment), PGY (postgraduate year), SD (standard deviation), SDE (scleral depression examination)
      Acute onset of flashes or floaters is one of the most common urgent symptoms in ophthalmology practice, usually heralding a posterior vitreous detachment (PVD). Rates of retinal tear or detachment in patients with symptomatic PVD range from 14% to 22%.
      • Hollands H.
      • Johnson D.
      • Brox A.C.
      • et al.
      Acute-onset floaters and flashes: is this patient at risk for retinal detachment?.
      • Coffee R.E.
      • Westfall A.C.
      • Davis G.H.
      • et al.
      Symptomatic posterior vitreous detachment and the incidence of delayed retinal breaks: case series and meta-analysis.
      • Uhr J.H.
      • Obeid A.
      • Wibbelsman T.D.
      • et al.
      Delayed retinal breaks and detachments after acute posterior vitreous detachment.
      Furthermore, 33% to 46% of untreated symptomatic retinal tears during a PVD event result in retinal detachment.
      • Shea M.
      • Davis M.D.
      • Kamel I.
      Retinal breaks without detachment, treated and untreated.
      A careful examination of all patients with flashes or floaters is imperative because laser treatment or cryoretinopexy of tears can reduce the incidence of detachment to less than 5%.
      • Flaxel C.J.
      • Adelman R.A.
      • Bailey S.T.
      • et al.
      Posterior vitreous detachment, retinal breaks, and lattice degeneration Preferred Practice Pattern®.
      At most United States academic centers, patients who seek treatment after business hours with symptoms of flashes or floaters are evaluated by first-year (postgraduate year [PGY] 2) or second-year (PGY 3) residents.
      • Mccoskey M.
      • Shafer B.M.
      • Nti A.A.
      • et al.
      First-year ophthalmology residency call structure and its association with resident anxiety and confidence.
      However, the backbone of the clinical examination for retinal tears, scleral depression, is perhaps one of the most difficult physical examination skills to master, and most research on detecting retinal tears has involved examinations by postresidency ophthalmologists. In this study, we determined patient outcomes and resource use for urgent, after-business hours screening of patients with symptoms consistent with a PVD, retinal tear, or retinal detachment by the on-call junior resident at the University of Michigan, a major academic medical center.

      Methods

      Institutional review board or ethics committee ruled that approval was not required for this quality improvement study. All research adhered to the tenets of the Declaration of Helsinki. University of Michigan Internal Review Board policies do not require informed consent to be obtained for quality improvement studies that involve large numbers of patients whose information has been completely anonymized, as was done for this study. The University of Michigan residency call structure, like most residency programs across the United States, relies on junior residents. First-year (PGY 2) residents begin taking calls 4 weeks into their training. During the first 2 rotations, each lasting 7 weeks, examinations are confirmed by a senior resident. Starting on the third rotation (14 weeks into the first year), first-year residents are no longer assisted by senior residents. They instead call the senior resident, fellow, or attending physician to discuss their plan, with the senior resident or fellow coming in to confirm examination findings at their discretion. Residents receive ocular ultrasound training in the first weeks of PGY 2 and therefore are equipped to use B-scan ultrasonography when they start call duty.
      All patients seen on-call at the University of Michigan between January 2017 and December 2017 were reviewed daily by J.M.L.M. at the end of each call shift in consultation with the on-call resident. Patients demonstrating flashes, floaters, curtain, or blurred vision (FFCBV) across the entire visual field without an anterior segment, lens, focal retinal, or neuro-ophthalmic cause (FFCBV symptoms) were screened. Of the 257 patients who met screening criteria, 29 did not follow-up at the University of Michigan within 6 months and therefore were excluded, leaving 228 patients for final analysis. Fourteen patients sought treatment multiple times, resulting in 246 unique screening events. For each screening event, all of the following information was recorded: patient age, gender, best-corrected visual acuity, presenting symptom(s), history of retinal tear or detachment, lens status, retinal findings (lattice, tuft, intraretinal hemorrhage (heme), proliferative diabetic retinopathy, sickle-cell retinopathy, commotio, retinoschisis, or endophthalmitis), vitreous findings (heme, Shafer sign), examination performed (indirect funduscopy without scleral depression, scleral depression examination [SDE], B-scan ultrasonography, or Goldmann 3-mirror lens technique), encounter month and time of week, patient volume on day of encounter, confirmation of examination findings by a fellow or senior resident, identity and PGY status of on-call resident, and presence of a tear or detachment. Follow-up data for each encounter included: time to follow-up appointment, follow-up clinic type (retina vs. nonretina), and presence of a tear or detachment. All follow-up examinations were performed by an attending, a fellow, or a PGY 4 resident staffed by an attending.
      For risk factor analysis, we used generalized estimating equation models with binary distribution and logit link function for outcomes of true tears or detachments, false-positive tears or detachments, false-negative tears, and clinic follow-up (retina vs. non-retina). For the outcome of time to follow-up examination, we used a γ distribution with identity link function, accounting for multiple visits of the same patient with an exchangeable correlation matrix. A P value of less than 0.05 was considered statistically significant. Risk factors for final multivariate models were determined initially by their statistical significance in univariate models. All significant univariate predictors were modeled in multivariate analysis. Risk factors that were significant additionally in multivariate analysis are those reported in the study, unless otherwise indicated.

      Results

       Patient Demographics, Presenting Symptoms, and Examination Findings

      The median ± standard deviation (SD) patient age was 59.0 ± 13.4 years, with an age distribution highly concentrated between 51 and 70 years of age (Fig 1A ). Most patients demonstrated best-corrected visual acuity of 20/25 or better (Fig 1B). Nevertheless, 55.7% of the 246 screening events found vitreous heme or Shafer sign on examination. Key demographic, presenting symptoms, and examination findings can be found in Table 1.
      Figure thumbnail gr1
      Figure 1Bar graphs showing the (A) age distribution and (B) visual acuity at presentation. CF = counting fingers; HM = hand movements.
      Table 1Patient Demographics, Presenting Symptoms, and Examination Findings
      CharacteristicNo./Total (%)
      Gender
       Female122/228 (53.7)
       Male106/228 (46.3)
      Symptoms
       Flashes ± floaters only148/246 (60.2)
       Included blurred vision ± curtain98/246 (39.8)
      History of retinal tear or detachment
       Contralateral eye22/246 (8.9)
       Ipsilateral eye14/246 (6.5)
       Both eyes12/246 (4.9)
      Pseudophakia
       Ipsilateral eye57/246 (23.2)
      Vitreous examination findings
       Only Shafer sign55/246 (22.4)
       Only heme52/246 (21.1)
       Heme + Shafer sign30/246 (12.2)
      Retinal examination findings
       Heme46/246 (18.7)
       Lattice35/246 (14.2)
       Tufts11/246 (4.5)
       Commotio2/246 (0.8)
       Endophthalmitis1/246 (0.4)
       Retinoschisis1/246 (0.4)
      Neovascular cause
       Diabetic retinopathy15/246 (6.1)
       Sickle cell retinopathy1/246 (0.4)

       On-Call Volume, Personnel Use, and Examination Type

      The average number ± SD of consultations during a call shift when an FFCBV examination was performed was 7.6 ± 3.5 per weekday (5 pm–7 am) and 14.4 ± 5.4 per weekend or holiday (average shift, approximately 18 hours). Of all FFCBV examinations, 44.3% involved a first-year resident and the remainder involved a resident in the first 6 months of the second year as the primary examiner. On-call residents used a range of examination techniques for FFCBV encounters (Table 2), including scleral depression and B-scan ultrasonography in 76.4% and 41% of all encounters, respectively.
      Table 2Examination Techniques and Detection of Retinal Tears and Detachments
      Technique and PathologyNo./Total (%)
      Technique used
       Direct fundoscopic examination21/246 (8.5)
       Direct fundoscopic examination + B-scan ultrasonography30/246 (12.2)
       Scleral depressed examination122/246 (49.6)
       Scleral depressed examination + B-scan ultrasonography64/246 (26.0)
       Other
      Indicates B-scan only or examination that included use of Goldmann 3-mirror lens technique.
      9/246 (3.7)
      Pathologic features detected
       True retinal tear26/246 (10.6)
       True retinal detachment47/246 (19.1)
       False positive retinal tear8/246 (3.2)
       False positive retinal detachment2/246 (0.8)
       False-negative retinal tear13/246 (5.3)
       No pathologic findings150/246 (61.0)
      Indicates B-scan only or examination that included use of Goldmann 3-mirror lens technique.
      A senior resident or fellow serving as back-up came in to confirm examination findings in 14.2% and 9.8% of FFCBV encounters, respectively. Of the 24.0% of encounters involving a second physician, 67.8% involved a first-year resident as the primary call resident, and 30.5% were the result of the mandatory rule that all first-year resident examinations performed on-call in the first 4 months of training are confirmed in person.

       Detection of Tears and Detachments

      Of all FFCBV on-call encounters, 13.8% identified a perceived retinal tear and 19.9% identified a perceived retinal detachment. On follow-up, a retinal tear was not confirmed in 8 patients and a retinal detachment was not confirmed in 2 patients, leading to false-positive tear and detachment rates of 3.3% (8/246) and 0.8% (2/246), respectively (Table 2). Predictors of a false-positive tear or detachment compared with those with truly negative examination results, as assessed by multivariate logistic regression, included the use of a B-scan ultrasonography during the examination and the presence of peripheral retinal heme (Table 3).
      Table 3Multivariate Predictors of True Retinal Tear and False-Positive Tear or Detachment
      VariablesOdds Ratio95% Confidence IntervalP Value
      Statistically significant multivariate predictors of a true retinal tear or detachment at initial or follow-up examination (n = 86 for tear or detachment, n = 160 for no tear or detachment)
       Visual acuity (logMAR)2.151.21–3.830.009
       Curtain in vision16.134.12–63.20<0.0001
       Vitreous heme2.481.07–5.750.034
       Shafer sign8.884.26–18.54<0.0001
      Statistically significant multivariate predictors of a false-positive tear or detachment (n = 10) versus truly negative examination results (n = 150)
       B-scan ultrasonography performed6.311.52–26.250.011
       Peripheral intraretinal heme3.861.10–13.520.035
      logMAR = logarithm of the minimum angle of resolution.
      Predictors of a true tear or detachment at any point during initial examination or follow-up, as assessed by multivariate logistic regression, included presenting visual acuity, the perception of a curtain in the vision, and heme or pigmented cell on the anterior vitreous examination (Table 3). Interestingly, peripheral retinal tufts and intraretinal heme were not predictive of a true tear or detachment on univariate analysis (Table S1, available at www.ophthalmologyretina.org). Furthermore, although a history of retinal tear or detachment and lattice degeneration were predictive of a true tear or detachment in univariate analysis, neither of these factors were predictive of a tear or detachment on multivariate analysis (Table S1).
      Of critical concern was the rate of tears or detachments not identified during the on-call encounter, but detected on follow-up, which we term false-negative tears. Although 5.3% (13/246) of on-call encounters with no identified tear on primary examination were found to have a tear on follow-up (Table 2), none of these tears progressed to detachment. Furthermore, there were no instances of a retinal detachment missed on-call but identified during follow-up. None of the 23 putative risk factors we assessed predicted a false-negative tear versus true-positive tear or detachment in multivariate analysis. Even in univariate analysis, neither the individual resident on-call, their training year, whether the examination was confirmed by a senior resident or fellow, or the number of patients seen during the call shift were predictive of a false-negative tear (Table S2, available at www.ophthalmologyretina.org). Of the 13 false-negative tears, 9 were triaged to our retina clinic with an average ± SD follow-up time of 2.1 ± 2.0 days based on concerning examination characteristics. The remaining 4 patients were triaged to a nonretina clinic with a follow-up times of 3 days, 3 days, 4 weeks, and 6 weeks.

       Time to and Type of Clinic Follow-up

      Flashes, floaters, curtain, or blurry vision on-call encounters were triaged to our retina clinic for follow-up 59.3% of the time. We sought to understand the necessity of retina clinic (vs. nonretina clinic) follow-up. Half of patients (73/146) attending the retina clinic for follow-up had a true tear or detachment. An additional 6.2% were thought to have a tear or detachment that was determined to be a false-positive finding by the retinal specialist, and 11.5% had vitreous hemorrhage or tractional retinal detachment resulting from proliferative diabetic retinopathy, sickle cell retinopathy, or endophthalmitis. Thus, 52 patients (35.6%) were referred to our retina clinic without pathologic findings (a perceived tear or detachment or proliferative diabetic retinopathy, sickle cell retinopathy, or endophthalmitis), either because they previously followed with the retina clinic or their examination findings were concerning. Of these 52 patients, 31 (59.6%) harbored vitreous heme or Shafer sign, and 9 (17.3%) were found to have a tear on follow-up. The analogous cohort that was triaged to nonretina clinics demonstrated vitreous heme or Shafer sign in 19.2% of patients (19/99) and delayed detection of a tear in 4.04% of patients (4/99) (Fig 2A ).
      Figure thumbnail gr2
      Figure 2Table and bar graph showing the (A) follow-up clinic type and (B) time to follow-up for patients with no initial pathologic features.
      The average time ± SD to follow-up for patients without pathologic features who did and did not have vitreous hemorrhage, Shafer sign, or both was 0.8 ± 0.9 weeks and 4.0 ± 4.1 weeks, respectively. The distribution of time to follow-up in our retina clinic versus nonretina clinics for patients without pathologic findings on initial examination is displayed in Figure 2B.
      To understand better the factors that predict the time to follow-up and clinic type for follow-up, we performed multivariate regression analysis after excluding patients with real or perceived tears or detachments and neovascular or infectious pathologic findings, because these patients automatically follow-up emergently in the retina clinic. The presence of vitreous hemorrhage was one of the most important predictors for both a short follow-up time and retina clinic referral (Table S3, available at www.ophthalmologyretina.org).

      Discussion

      A PVD is among the most common diagnoses made for patients with ophthalmic symptoms seeking treatment at an emergency department.
      • Heiferman M.J.
      • Khanna S.
      • Gu D.
      • et al.
      Emergency department ophthalmology consultations in a tertiary care hospital.
      Outcomes and resource use for patients with symptoms of a PVD, tear, or detachment seen by junior residents on-call has not been studied comprehensively. One prior study involved attending and senior residents performing a large number of initial emergency department examinations and junior residents performing some follow-up examinations.
      • Nassrallah G.
      • Kondoff M.
      • Ross M.
      • Deschenes J.
      Posterior vitreous detachment and incidence of delayed retinal breaks: a retrospective, 2-year study at an academic centre.
      Another study investigated all patients seeking treatment at the emergency department with an ophthalmic symptom, rather than just those with FFCBV symptoms, and did not detail patient or examination characteristics, follow-up times, or clinic types.
      • Heiferman M.J.
      • Khanna S.
      • Gu D.
      • et al.
      Emergency department ophthalmology consultations in a tertiary care hospital.
      Herein, by prospectively following up all patients seen on-call for a calendar year by first-year or early second-year residents, we showed that such a call system provides safe triage at the expense of modestly high resource use.
      The rate of true tear or detachment on initial presentation in our study was approximately 30%, higher than the 14% to 22% rate of tear or detachment after symptomatic PVDs reported previously.
      • Hollands H.
      • Johnson D.
      • Brox A.C.
      • et al.
      Acute-onset floaters and flashes: is this patient at risk for retinal detachment?.
      • Coffee R.E.
      • Westfall A.C.
      • Davis G.H.
      • et al.
      Symptomatic posterior vitreous detachment and the incidence of delayed retinal breaks: case series and meta-analysis.
      • Uhr J.H.
      • Obeid A.
      • Wibbelsman T.D.
      • et al.
      Delayed retinal breaks and detachments after acute posterior vitreous detachment.
      We suspect that our higher rate is primarily the result of patient self-selection, because patients with prominent symptoms, who are at greater risk for a tear or detachment,
      • Boldrey E.E.
      Risk of retinal tears in patients with vitreous floaters.
      • van Overdam K.A.
      • Bettink-Remeijer M.W.
      • Mulder P.G.
      • van Meurs J.C.
      Symptoms predictive for the later development of retinal breaks.
      • Karahan E.
      • Karti O.
      • Er D.
      • et al.
      Risk factors for multiple retinal tears in patients with acute posterior vitreous detachment.
      are more likely to seek treatment after hours than the next day. Risk factors that predicted a retinal tear or detachment in multivariate analysis included decreased visual acuity, perception of a curtain in the vision, and findings of vitreous heme or anterior vitreous pigmented cell, similar to what has been reported in the literature.
      • Hollands H.
      • Johnson D.
      • Brox A.C.
      • et al.
      Acute-onset floaters and flashes: is this patient at risk for retinal detachment?.
      Fully 55.5% of patients in our cohort demonstrated vitreous hemorrhage, Shafer sign, or both. Despite their perceived importance, peripheral retinal pathologic features, including retinal heme, lattice, or tufts, as well as a history of retinal tear or detachment, were not significant predictors in multivariate analysis. Instead, peripheral retinal heme actually was a predictor of false-positive tears, suggesting that this examination finding should be minimized as a reason for urgent or retina clinic follow-up.
      Scleral depression is the most widely accepted method for examining patients with FFCBV symptoms and is part of the American Academy of Ophthalmology’s Preferred Practice Pattern guidelines for symptomatic PVDs.
      • Flaxel C.J.
      • Adelman R.A.
      • Bailey S.T.
      • et al.
      Posterior vitreous detachment, retinal breaks, and lattice degeneration Preferred Practice Pattern®.
      Scleral depression is difficult to master,
      • Tran K.D.
      • Schwartz S.G.
      • Smiddy W.E.
      • Flynn H.W.
      The role of scleral depression in modern clinical practice.
      with only 37.5% of final-year residents achieving high confidence with the technique in a survey of Canadian ophthalmology residents.
      • Arjmand P.
      • Hurley B.
      Flashes and floaters: a survey of Canadian ophthalmology residents’ practice patterns.
      Although the evidence supporting its effectiveness is conflicting,
      • Shukla S.Y.
      • Batra N.N.
      • Ittiara S.T.
      • Hariprasad S.M.
      Reassessment of scleral depression in the clinical setting.
      ,
      • Natkunarajah M.
      • Goldsmith C.
      • Goble R.
      Diagnostic effectiveness of noncontact slitlamp examination in the identification of retinal tears.
      nearly 90% of retina specialists in a nationwide survey use SDE for FFCBV symptoms.
      • Shukla S.Y.
      • Batra N.N.
      • Ittiara S.T.
      • Hariprasad S.M.
      Reassessment of scleral depression in the clinical setting.
      In our study, approximately 75% of examinations involved SDE. Ocular surgery within the past month, any question of an open globe, or dense vitreous hemorrhage with no view to the fundus explains the decision not to use scleral depression in at least some encounters. B-scan ultrasonography is an effective adjunctive tool in the diagnosis of retinal tears and detachments, especially when vitreous hemorrhage or other media opacity are present.
      • Lorenzo-Carrero J.
      • Perez-Flores I.
      • Cid-Galano M.
      • et al.
      B-scan ultrasonography to screen for retinal tears in acute symptomatic age-related posterior vitreous detachment.
      ,
      • Margo C.E.
      • Harman L.E.
      Posterior vitreous detachment. How to approach sudden-onset floaters and flashing lights.
      The high rate of B-scan ultrasonography use in this study (more than 40% of encounters) may have augmented tear or detachment detection in examiners uncomfortable with SDE.
      Only 5.3% of FFCBV on-call encounters involved a tear identified on follow-up examination that was not established at the on-call examination. Based on high-risk characteristics on examination, 11 of these 13 patients with false-negative tears were seen at follow-up within a few days of the on-call examination. Importantly, no false-negative tear resulted in a retinal detachment at the time of follow-up, suggesting that the on-call system mitigates potential harm from inexperienced junior residents. Reassuringly, logistic regression analysis demonstrated that neither the specific resident on-call nor their level of training predicted a false-negative tear, despite varying levels of comfort with the peripheral retina examination among residents. We postulate that the on-call system’s support structure, including the availability of senior residents and fellows to confirm the findings from a difficult examination and the frequent adjunctive use of B-scan ultrasonography, helped to normalize differences among residents’ SDE facility.
      Although the on-call system proved effective for patients with FFCBV symptoms, we found a modestly high resource use rate. Approximately 25% of FFCBV encounters required a senior resident or fellow to confirm findings. However, 30.5% of these second-physician encounters were the result of the residency program’s mandatory rule that all on-call examination findings during the first 4 months of residency are confirmed.
      Another measure of resource use is the decision to refer a patient to retina clinic for follow-up. At our institution, the retina service routinely is the busiest, with longer patient wait times and less appointment availability than our comprehensive clinic; triaging patients to a nonretina clinic therefore is desirable when safe. Although approximately 60% of patients were seen at our retina clinic for follow-up, almost 60% of these patients had tears, detachments, or vitreous opacity resulting from other retinal pathology, mandating retina clinic follow-up. In patients triaged to the retina clinic for follow-up without a real or perceived tear or detachment, neovascular pathology, or endophthalmitis, subsequent examination revealed tears in 17.3% of patients, significantly higher than the 2% to 3.5% rate of delayed tears or detachments expected after initial examination in the literature
      • Hollands H.
      • Johnson D.
      • Brox A.C.
      • et al.
      Acute-onset floaters and flashes: is this patient at risk for retinal detachment?.
      • Coffee R.E.
      • Westfall A.C.
      • Davis G.H.
      • et al.
      Symptomatic posterior vitreous detachment and the incidence of delayed retinal breaks: case series and meta-analysis.
      • Uhr J.H.
      • Obeid A.
      • Wibbelsman T.D.
      • et al.
      Delayed retinal breaks and detachments after acute posterior vitreous detachment.
      and higher than the approximately 4% rate of delayed tears seen in patients referred to nonretina clinics for follow-up in our study. Thus, the modestly high rate of expeditious retina clinic follow-up for high-risk patients without tears or detachments may be required for maintaining safety of the on-call system.
      A final measure of resource use is the time to follow-up. Excluding those with real or perceived tears or detachments, neovascular pathology, or endophthalmitis, patients with vitreous hemorrhage or Shafer sign were seen, on average, within 1 week for follow-up, similar to the time frame for follow-up if they had sought treatment at attending-staffed clinics at our institution. Those without these signs were seen for follow-up at approximately 4 weeks, almost always in a nonretina clinic, in line with the community standard time frame for follow-up of unremarkable PVDs. Thus, time to follow-up for on-call FFCBV encounters was similar to that for standard, nonresident FFCBV encounters across our institution. We therefore conclude that moderate resource allocation supports a safe, junior resident-run on-call system for patients with FFCBV symptoms, driven mostly by 25% of initial encounters being confirmed in real time by senior residents or fellows as well as higher-risk patients being seen within days at the retina clinic versus nonretina clinics for follow-up.
      Our study carries limitations. Of the 257 patients seen on-call with FFCBV symptoms during 2017, 29 patients did not follow-up at the University of Michigan within 6 months, leaving a follow-up rate of 88.7%. We presume that some patients sought follow-up closer to home and others did not follow-up because they never experienced new symptoms. This likely would reduce the false-negative tear rate of 5.3% we report herein. We note that an overall follow-up rate of 88.7% compares favorably with that from a large study of all ophthalmic emergency room visits staffed by ophthalmology junior residents, where follow-up rate was closer to 63%.
      • Heiferman M.J.
      • Khanna S.
      • Gu D.
      • et al.
      Emergency department ophthalmology consultations in a tertiary care hospital.
      A second limitation of our study is that it does not address the efficacy and safety of after-hours phone triage of patients with FFCBV symptoms; the study analyzes only those persons who were seen in an on-call scenario, many of whom arrived at the emergency department without prior call or notification. For those patients with FFCBV symptoms who do contact the on-call resident for advice, the resident always provides the option to be seen that night or the next day in the clinic. When the clinic is closed the following day (holidays, weekends), the resident requests that the patient be seen on an on-call basis. For patients then found to have a retinal tear during an on-call examination, retinopexy is performed within 24 hours at a follow-up visit by the retina fellow, but not in real time by the on-call resident. For patients found to have a retinal detachment during an on-call examination, the preoperative preparation, including consent, history and physical examination, and operating room notification, are all performed during the call encounter, clearing the way for the surgery to go as the first case the next morning (weekday) or later in the day (weekend).
      A third limitation of our study is that false-negative tears instead may represent delayed onset of a tear. The literature suggests that retinal tears develop after an initial examination for symptomatic PVD in approximately 2% to 3.5% of patients.
      • Hollands H.
      • Johnson D.
      • Brox A.C.
      • et al.
      Acute-onset floaters and flashes: is this patient at risk for retinal detachment?.
      • Coffee R.E.
      • Westfall A.C.
      • Davis G.H.
      • et al.
      Symptomatic posterior vitreous detachment and the incidence of delayed retinal breaks: case series and meta-analysis.
      • Uhr J.H.
      • Obeid A.
      • Wibbelsman T.D.
      • et al.
      Delayed retinal breaks and detachments after acute posterior vitreous detachment.
      In our study, of the 13 false-negative tears, 11 had an average ± SD follow-up time of 2.3 ± 1.8 days, whereas 2 others were seen at 4 and 6 weeks, respectively. It is possible that some tears developed within a few days of the on-call examination, but it is also likely that some of these early follow-up encounters were true missed tears. However, truly delayed tears may have developed in the patients who were seen at 4 and 6 weeks. If we assume that the 11 encounters with short follow-up time all constitute true missed tears, then the true missed tear rate would be no more than 4.5% (11/246).
      Finally, varying aptitudes among junior residents across the world handling FFCBV symptoms on-call potentially limits the generalizability of our single-center study. Nevertheless, neither the specific resident on-call nor his or her training year predicted a false-negative tear, suggesting that replication of the call structure at the University of Michigan may mitigate variations in resident competency and produce similar results at other programs. Key call structure components that may counter differences in resident scleral depression skill include a high B-scan ultrasonography use rate to augment detection of large flap tears and shallow retinal detachments, the presence of a buddy call for the first 14 weeks of the first year (PGY 2) of residency, the ready availability of senior residents and fellows for real-time confirmatory examinations (approximately 24% of encounters), and the recognition by junior residents that patients with easily identifiable high-risk examination characteristics should have follow-up within days, preferably in the retina clinic.
      In conclusion, in our year-long prospective study of patients presenting on-call at a major academic medical center, junior residents appropriately triaged patients with symptoms of a PVD, retinal tear, or retinal detachment, with a false-negative tear rate of no more than 5.3%. No missed tear progressed to a detachment at the time of follow-up, showing that junior residents appropriately adjusted the interval for follow-up based on high-risk examination characteristics. The appropriate triage of patients came at the cost of modestly high resource expenditure, including confirmatory examinations by senior residents or fellows in approximately 25% of encounters and a high proportion of high-risk patients without tears being triaged for retina clinic follow-up within days of the initial examination.

      Acknowledgments

      The authors thank Nathan Liles, MD, MPH, for advice on statistical modeling.

      Supplementary Data

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