Comparison of dacryocystography and lacrimal scintigraphy in the diagnosis of functional nasolacrimal duct obstruction

Evaluation of primary acquired nasolacrimal duct obstruction: Comparison of CT-DCG and dacryoendoscopy in accurately localizing the lacrimal drainage obstructions

OBJECTIVE

To correlate and evaluate the power and limitations of CT-DCG in determining the level and type of lacrimal duct obstruction in comparison to dacryoendoscopy in patients clinically suspected to be having partial or complete primary acquired nasolacrimal duct obstruction (PANDO).

METHODS

A retrospective chart review was performed on 1232 lacrimal drainage systems of 957 patients who suffered from primary acquired nasolacrimal duct obstruction (PANDO) at Shanghai Ninth People's Hospital. Patients were examined with CT-DCG and correlated with dacryoendoscopy and the findings of clinical examination.

RESULTS

Of the studied patients, 173 were men and 784 were women with an age range of 18-93 years. Of the 1232 lacrimal pathways, good CT-DCG images could be obtained in 980 cases and dacryoendoscopy in 957 cases. Of these complete obstructions were noted in 81% (794/980), and partial obstructions were identified in 19% (186/980) with CT-DCG. CT-DCG and dacryoendoscopy showed 68.4% agreement for the type of the obstruction and 63% for the level of the obstruction. The majority of the obstructions occurred at the sac-duct junction (62.5%) followed by the upper half of the nasolacrimal duct (27.5%). There was a significant difference in the correlation of the obstruction type with age group and with the duration of symptoms. As the duration of symptoms increased, the proportion of complete lacrimal duct obstructions as shown on CT-DCG images increased and the proportion of incomplete obstruction decreased (p = 0.015).

CONCLUSIONS

The junction of lacrimal sac and nasolacrimal duct was the most common obstruction site. Age and the duration of symptoms influenced the type of obstruction noted. The degree and level of agreement between the investigations was moderate. A combination of CT-DCG and Dacryoendoscopy could together identify the location more accurately.

A Pilot Study of Dynamic Magnetic Resonance Dacryocystography Imaging to Assess Functional Epiphora

OBJECTIVE

To evaluate dynamic magnetic resonance dacryocystography (MRDCG) in eyes with functional epiphora.

METHODS

We included prospective eyes with epiphora if no alternative cause was found on clinical examination, were patent on syringing, had no obstruction or stenosis on DCG, and had an abnormal DSG. MRDCG was performed to qualitatively assess for block or patency and quantitatively measure tear transit time. We compared measurements to asymptomatic fellow eyes and to historical reference values from asymptomatic eyes.

RESULTS

We included 26 symptomatic eyes of 19 patients (median age 63 years). There was a block on MRDCG in 18 (69%) eyes and patency in 8 (31%) eyes. The block occurred at the sac-nasolacrimal duct (NLD) junction in 9 (50%), proximal NLD in 5 (28%), mid-NLD in 1 (5.6%), and distal NLD in 1 (5.6%) eye(s). No contrast was observed in the lacrimal system in two eyes. For eyes patent on MRDCG, median times to the sac, NLD, inferior meatus, first 25%, and first 50% of the fundus-to-nose distance (FND) were 22, 54, 118, 34, and 84 s, respectively. Times to the sac, NLD, and to fill the first 25% and 50% of the FND were significantly longer than historical values from asymptomatic lacrimal systems (p = 0.017, 0.050, 0.035, 0.017, respectively).

CONCLUSION

MRDCG shows a high rate of block in functional epiphora. However, DSG and MRDCG results may not always correlate. The improved temporal resolution of this emerging modality may be advantageous in the critical first 2 min of tear transit.

Functional epiphora: an under-reported entity

PURPOSE

To determine the etiology of epiphora in a tertiary Australian lacrimal clinic and highlight the high proportion of 'functional' cases.

METHODS

Single-center retrospective review: Records of adult patients presenting to a tertiary lacrimal clinic from January 2011 to February 2021 with epiphora were reviewed. Patients underwent testing with syringing/probing and lacrimal imaging to reach a diagnosis of functional epiphora. Functional epiphora was diagnosed based on the exclusion of alternate causes of epiphora on clinical examination, patent lacrimal syringing, normal dacryocystography, and delay on dacryoscintigraphy.

RESULTS

Five hundred and seventy-six symptomatic eyes of 372 adult patients (mean 66.2 ± 15.5 years, 63.4% females) with epiphora were evaluated for causes. Post-sac obstruction (stenosis/complete obstruction) and functional epiphora (non-anatomical delay) were the most common causes of presentations to the lacrimal clinic (26% each). Functional epiphora with post-sac delay was substantially more common than functional epiphora with pre-sac delay (89% vs. 11% of functional epiphora cases). In 16% of the cases, no cause for the epiphora was found while more than one cause (multifactorial) was present 11% of the time.

CONCLUSION

Functional epiphora was found to be as common as a nasolacrimal anatomical obstruction when lacrimal imaging is utilized.

Dacryoscintigraphy as a guide for surgery in patients with functional epiphora

OBJECTIVE

To investigate how dacryoscintigraphy (DSG) may benefit surgical planning for functional epiphora.

METHODS

A retrospective multicentred case series was performed on patients with symptomatic tearing despite no identified external cause and normal lacrimal probing and irrigation (i.e., functional epiphora). All patients had preoperative DSG testing. Patients were excluded if DSG testing failed to detect a tear flow abnormality. Those with delayed tear flow prior to entering the lacrimal sac (presac) on DSG underwent surgery aimed at improving flow into the lacrimal sac. Those with delayed tear flow after the lacrimal sac (postsac) on DSG underwent dacryocystorhinostomy. Surgical success was defined as complete resolution of the epiphora, significantly improved, or partially improved. Surgical failure was defined as epiphora being unchanged or worse than at the preoperative timepoint.

RESULTS

A total of 77 cases (53 patients) of DSG-guided surgery were included. A presac delay was observed in 14 cases (18.2%) and post-sac delay in 63 (81.8%). Overall surgical success was 83.1% across the cohort. Success was 100% in the presac group and 79.4% in the postsac group (p = 0.06). Mean follow-up time was 22 months (SD = 21 months).

CONCLUSION

A role was demonstrated for DSG in the planning of surgery for patients with functional epiphora. The DSG-guided approach, when compared with empirical lacrimal intubation or dacryocystorhinostomy, may be especially useful in cases of functional epiphora that are presac in nature.

Normative Quantitative Values for Dacryoscintigraphy and the Effect of Lid Massage

Our objectives were to establish normative quantitative values for dacryoscintigraphy in an older population and to evaluate the effect of lid massage. Methods: We conducted a prospective study of 44 eyes of 22 participants aged between 54-90 y that had no symptoms of epiphora and no clinical tear film instability, lid abnormality, lacrimal system impairment, or patent lacrimal duct on syringing. Dacryoscintigraphy was performed and interpreted by a single nuclear medicine physician. The scan protocol involved instillation of ^99mTc-pertechnetate in each eye, with a 45-min scan performed with 1-min frames. Lid massage and a sinus clearing maneuver were then performed, followed by a further 45 min of scanning. Results: The mean age of the 22 participants was 71.9 y. Quantitative analysis by half-clearance time (HCT) demonstrated a median presac HCT of 25.5 ± 15.0 min and a whole-eye HCT of 40.0 ± 19.5 min. There was no association between age or sex and HCT. Qualitatively, 29 of 44 eyes (66%) appeared to have at least 1 region of delayed clearance, with improvement noted in 23 after lid massage (79%). Conclusion: We report the quantitative values for dacryoscintigraphy in an asymptomatic older population who had normal findings on lacrimal examination. A high rate of delay in radiotracer transit on qualitative examination suggesting a low specificity. The false-positive rate was significantly improved with the novel approach of adding lid massage, and the significance of this finding merits further research.

Functional Versus Anatomical Nasolacrimal Obstruction: Are There Differences in Epiphora Severity, Symptoms, or Effects on Quality of Life?

PURPOSE

To elucidate whether the specific cause of nasolacrimal duct drainage impairment impacts the severity, symptoms, and implications on visual tasks and quality of life (QOL) in epiphora.

METHODS

A retrospective review of consecutive adult patients with epiphora attending a tertiary lacrimal clinic from June 2011 to March 2021 was conducted. Cases with evidence of canalicular stenosis, a mucocele, or other identifiable causes of epiphora were excluded. A structured interview assessed the epiphora severity (Munk), symptomatology, precipitating factors, and effects on visual tasks and QOL. Following lacrimal syringing, all eyes were investigated with dacryocystography and dacryoscintigraphy. The domains of the interview were compared between nasolacrimal duct obstruction (NLDO), stenosis (NLDS), and nonanatomical functional delay (FNLDO).

RESULTS

One hundred twenty-two symptomatic eyes (63 patients; mean age 63.3 ± 17.2 years; 59% females) were included. There was no difference in Munk score between the groups (NLDO = 3.71 ± 0.18, NLDS = 3.79 ± 2.0, FNLDO = 3.85 ± 0.15; p = 0.82). In all 3 groups, most cases had a Munk >2 (86.8%, 75.9%, and 89.1%, respectively; p = 0.25). Discharge was more common in NLDO (65.7%) compared with NLDS (30.0%) and FNLDO (36.4%, p = 0.006). Worsening in the cold/wind was more frequent in FNLDO (77.1%) compared with NLDO (48.5%, p = 0.029). Effects on visual tasks and QOL were not significantly different.

CONCLUSIONS

FNLDO patients experience a high severity of epiphora, comparable to patients with NLDS and those with complete NLDO. The distinction between FNLDO and NLDS had little consequence on reported symptoms, precipitating factors, visual tasks, and QOL. Discharge may be more specific to NLDO, whereas precipitating cold or wind is more specific to FNLDO.

Diagnostic value of lacrimal scintigraphy in the evaluation of lacrimal drainage system obstruction: a systematic review and meta-analysis

PURPOSE

A systematic review and meta-analysis to evaluate the diagnostic performance of lacrimal scintigraphy (LS) versus anatomical methods in the evaluation of the nasolacrimal duct obstruction (NLDO).

MATERIALS AND METHODS

A systematic search was performed using electronic bibliographic databases until the end of May 2021. Inclusion criteria: (a) used LS as a diagnostic method to evaluate NLDO; (b) used anatomical studies [including syringing, irrigation, probing, and dacryocystography (DCG)] as reference tests; and (c) provided adequate crude data. A hierarchical method was used to pool the sensitivity and specificity. The hierarchical summary receiver-operating characteristic model was performed. Additionally, the studies' heterogeneity and publication bias were analyzed. All analyses were conducted by the 'Midas' module of STATA 16.

RESULTS

Twelve articles (with 14 separate populations) were considered eligible to enter the meta-analysis. They were divided into two groups based on the reference standard method, called irrigation and DCG groups. In the irrigation group, the pooled sensitivity and specificity were 89% [95% confidence interval (CI), 72-96%] and 25% (95% CI, 8-56%), respectively. In DCG group, the pooled sensitivity and specificity were 97% (95% CI, 85-100%) and 27% (95% CI, 0.12-0.49), in turn.

CONCLUSION

LS is a sensitive modality to evaluate the anatomical obstruction of NLD. In contrast, it shows low pooled specificity compared with anatomical methods. Thus, LS can be used as the first noninvasive modality for the evaluation of epiphora. However, in case of any abnormality, confirmatory procedures are required.

Syringing has limited reliability in differentiating nasolacrimal duct stenosis from functional delay

PURPOSE

To elucidate the role of syringing in assessing nasolacrimal duct (NLD) stenosis and non-anatomical functional NLD delay.

METHODS

Consecutive adult patients with epiphora attending a tertiary lacrimal clinic from June 2011 to March 2021 were reviewed. Cases with evidence of canalicular stenosis or other identifiable causes of epiphora were excluded. Following syringing, patients were investigated with dacryocystography (DCG) and dacryoscintigraphy (DSG). The sensitivity and specificity of syringing were evaluated using the combined findings on DCG and DSG.

RESULTS

A total of 289 symptomatic lacrimal systems (197 patients; mean age 65.5 ± 14.9 years, 66% females) were included. More than one-third of cases with both normal DCG and DSG were noted to have some degree of reflux on syringing (specificity = 65.1%, 95% CI 50.2-77.6%). The sensitivities were considerably low for NLD stenosis (i.e., stenosis on DCG and delay on DSG) and for functional NLD delay (i.e., normal DCG and delay on DSG), of which 43.7% (95% CI 32.2-55.9%) and 54.3% (95% CI 45.7-62.7%) had full patency on syringing, respectively (p = 0.17).

CONCLUSIONS

Full patency on syringing was unreliable for ruling out NLD stenosis and functional delay. Furthermore, a positive syringing may be associated with functional NLD delay and cannot reliably differentiate it from stenosis.

Can preoperative lacrimal endoscopic evaluation change the paradigm of conventional lacrimal surgery?

PURPOSE

To evaluate the effectiveness of preoperative lacrimal endoscopic evaluation (LEE) of lacrimal duct system (LDS).

DESIGN

Retrospective comparative case series METHODS: From March 2016 to February 2020, the charts of patients chosen to undergo endoscopic dacryocystorhinostomy (EDCR) or silicone tube intubation (STI) were reviewed retrospectively. Group 1 included patients that underwent EDCR, and group 2 included patients that underwent STI. Preoperative LEE was performed for all patients. In group 1, we compared the functional success rate for patients who had been converted to STI with the patients who had undergone EDCR. In group 2, we compared the functional success rate of STI with those who had had STI without LEE.

RESULTS

In group 1, 19 (54.3%) eyes were converted to STI following LEE, and the functional success rate was 84.2%, which is not significantly different from that of the EDCR group following LEE (p = 0.608). The functional success rate of EDCR without LEE was not different from that of STI following LEE (p = 1.000). In group 2, five eyes (26.3%) were converted to EDCR following LEE. The group undergoing STI following LEE showed a significantly higher functional success rate (95.7%) than the group without LEE (66.6%, p = 0.023).

CONCLUSION

Preoperative LEE enables direct visualization of the LDS and helps to obtain more accurate diagnosis. This allows for the best surgical option based on LEE findings, which can contribute to better results. Therefore, LEE would be expected to change the paradigm of the classical management of LDS.

Lacrimal scintigraphy BNMS Guidelines

PURPOSE

The purpose of this guideline is to assist specialists in Nuclear Medicine and Radionuclide Radiology in recommending, performing, interpreting and reporting the results of lacrimal scintigraphy (also known as Dacroscintigraphy). This guideline will assist individual departments to formulate their own local protocols. This does not aim to be prescriptive regarding technical aspects of individual camera acquisitions, which need to be developed in conjunction with the local experts in medical physics. There are numerous radiological techniques to assess the physiology of the lacrimal system. This guideline will describe the application of a drop of radiotracer into each eye and consecutive imaging to demonstrate the level of impaired drainage, with the possibility of quantifying such impairment. This guideline is a recent and updated version of a previously published guideline on the British Nuclear Medicine Society website in 2018 [1].

Pilot study of a nurse-led adult lacrimal clinic at a tertiary ophthalmic centre

This article provides the reader with an outline of the anatomy and physiology of the lacrimal system and illustrates how a variety of pathologies within this system can result in the development of a watery eye. It describes the role of the nurse consultant in the diagnosis and management of patients with watery eye in the lacrimal clinic, and how the training programme for the development of such skills was implemented. Following training, within the realms of an established pilot study, the nurse consultant began to implement her skills in a newly established nurse-led lacrimal clinic. Patients seen in the lacrimal clinic would previously have been assessed and managed by a doctor. To confirm the accuracy of this approach, an audit was undertaken comparing the nurse-led diagnosis and management plans with that of an oculoplastic doctor. In addition, patient waiting times in the clinic and patient satisfaction were assessed, as important indicators of quality of care.

Association between septoplasty, Lund-Mackay score and Lund-Kennedy score with endoscopic dacryocystorhinostomy results

PURPOSE

To compare endoscopic dacryocystorhinostomy (endo-DCR) + septoplasty with endo-DCR alone and determine the relationship between sinusitis and endo-DCR surgery results.

METHODS

Our study included 55 patients with nasolacrimal duct obstruction (NLDO) between June 2017 and June 2019. Patients were divided into two groups as endo-DCR alone and endo-DCR + septoplasty. Patients' symptoms were thoroughly evaluated and scored using the Lund-Mackay (LM) score and the Lund-Kennedy (LK) system. According to LK endoscopy scoring; those with a score of 0 were determined as group 1 (40 (58.8%) cases); and those with a score greater than 0 were determined as group 2 (28(41.2%) cases). According to LM CT scoring system, cases whose score was 0 were determined as group 1 (44(%66.2) cases); those greater than 0 were determined as group 2 (23(33.8%) cases).

RESULTS

A total of 68 endo-DCR surgeries, 42 unilateral and 13 bilateral, were performed. Forty one cases (60.3%) were managed with endo-DCR alone, and septoplasty surgery was performed in 27 (39.7%) cases in addition to endo-DCR due to septum deviation. There was no statistically significant difference in functional and anatomical success between the two groups in terms of surgery type (anatomical success p = .353, functional success p = .528); LK endoscopy scoring (anatomical success p = .956, functional success p = .925) and LM CT scoring system (anatomical success p = .202, functional success p = .172).

CONCLUSION

LK endoscopy and LM CT scores did not show any influence on functional and anatomic outcomes in endo-DCR cases.

Comparison of digital subtraction dacryocystography and dacryoendoscopy in patients with epiphora

OBJECTIVE

To assess the diagnostic information provided by digital subtraction dacryocystography (DCG) and dacryoendoscopy in patients with epiphora.

METHODS

Sixty-eight lacrimal systems of 34 patients with epiphora were prospectively studied. Patients were initially examined with syringing, followed by digital subtraction DCG and dacryoendoscopy to confirm the diagnosis. Obstructions in lacrimal pathways were evaluated by degree, location, and cause. The weighted kappa coefficient was used to compare the agreement between the tests.

RESULTS

Of the 68 lacrimal pathways, partial or complete obstructions were identified in 56 cases (82.3%) with syringing, in 38 cases (55.9%) with DCG, and in 60 cases (88.2%) with dacryoendoscopy. DCG and dacryoendoscopy showed the same result in 42 of the 68 (61.8%) lacrimal pathways. The weighted kappa value for DCG and dacryoendoscopy was 0.60 (95% CI: 0.40-0.81). The most common sites of obstruction were the common canaliculus (36.7%) and the nasolacrimal duct (28.3%) in dacryoendoscopy. Thirty-three lacrimal pathways (48.5%) were identified to have obstructions on the same level between DCG and dacryoendoscopy. Among the 30 lacrimal pathways (44.1%) that were normal by DCG, obstruction was revealed in 22 cases by dacryoendoscopy, with 11 cases in the common canaliculus. Additional useful information on the cause of obstruction and identification of multiple obstructed sites was provided by dacryoendoscopy.

CONCLUSIONS

DCG and dacryoendoscopy showed moderate agreement in detecting lacrimal pathway obstruction. Dacryoendoscopy allowed for comprehensive investigations of the lacrimal pathway and can help explain unidentified factors associated with lacrimal pathway obstruction in patients with epiphora.

Tear transit time evaluation using real-time technique for dynamic MR dacryocystography

Purpose: To explore the utility of a novel real-time dynamic magnetic resonance dacryocystography (MRDCG) technique to assess the transit times through the lacrimal drainage system (LDS). Methods: Twenty-six patent LDS of 13 normal and asymptomatic individuals underwent MRDCG using a dynamic recalled three-dimensional spoiled gradient sequence (3DSPGR) on 1.5-Tesla magnetic resonance (1.5T MR) scanner while pre-determined diluted gadolinium drops were instilled into the eyes simultaneously. MR images of 0.8 mm thickness were captured every 9.4 s for 10 min. Evaluated parameters include the time taken for contrast to first appear in lacrimal sac, nasolacrimal duct (NLD), and inferior meatus (IM). Results: Dynamic MRDCG demonstrated contrast outflow in all cases with good structural delineation. The mean transit time for contrast to appear in lacrimal sac was 15.2 s (9.4-66 s; SD, 11.9), 50.4 s for nasolacrimal duct (18.9-151; SD, 32), and 150.5 s for inferior meatus (37.8-490; SD, 135). Contrast appeared in the IM in less than 2 min in 62% (16/26) systems, and only 19% (5/26) required more than 5 min. The maximum time taken for the contrast to reach IM was 6.2 min and all the LDS eventually showed the contrast into the nasal cavity. No statistically significant differences were noted in the transit times between the right and left sides. Conclusion: Dynamic MR-DCG using real-time 3DSPGR sequence reliably demonstrates the structural and physiological assessment of LDS and could be further explored to study the physiology and pathologies of the LDS.

Evaluation of Patients for Endoscopic DCR: Sac Syringing and Radionuclide Scintigraphy

To evaluate the importance of sac syringing and radionuclide scintigraphy for pre operative work up of patients with epiphora. In this study, from the year Jan. 2013 to Jan. 2016, patients of epiphora were subjected to radionuclide scintigraphy of lacrimal apparatus in addition to sac syringing and probing. The significance of adding radionuclide scintigraphy in pre op assessment of epiphora was statistically assessed. 146 lacrimal systems were enrolled in the study. Out of them, 89 were males and 57 were females. The mean age of the patients was 42 years. Of the 146 lacrimal systems evaluated, scintigraphy detected 25 cases of common canalicular block versus 8 cases by sac syringing. Also radionuclide scintigraphy was able to detect 11 cases of functional obstruction which were patent on syringing. Results were analysed statistically. Correct diagnosis of site of obstruction is essential to predict a better surgical outcome of endoscopic DCR as it is a highly successful surgical procedure which can be done in distal NLDO only. We recommend that all patients of epiphora should undergo sac syringing as an initial test. This is a simple, inexpensive procedure which can be done as an OPD procedure in a short time. However, radionuclide scintigraphy can be added as an additional investigation to more accurately delineate site of block. It is an objective test and delineates the lacrimal system both anatomically and functionally. Also it diagnoses functional block which appears patent on syringing.

Time-resolved three-dimensional technique for dynamic magnetic resonance dacryocystography

IMPORTANCE

This study introduces a new technique in the assessment of nasolacrimal drainage with magnetic resonance imaging.

BACKGROUND

To describe a new dynamic magnetic resonance dacryocystography (MRDCG) protocol and report normative findings on asymptomatic lacrimal drainage systems.

DESIGN

A prospective observational study at the Royal Adelaide Hospital.

PARTICIPANTS

Seventeen patients with unilateral epiphora were prospectively recruited.

METHODS

Patients underwent dynamic MRDCG. The time-resolved angiography with interleaved stochastic trajectories (TWIST) sequence was used to visualise contrast flow through the lacrimal drainage system.

MAIN OUTCOME MEASURES

Tear transit times and anatomical dimensions were measured.

RESULTS

Dynamic MRDCG with TWIST sequence reliably demonstrated contrast flow. Tear transit times and anatomical dimensions were comparable to previously reported values in other imaging modalities.

CONCLUSIONS AND RELEVANCE

Dynamic MRDCG provides good structural and temporal resolution to the assessment of lacrimal outflow obstructions. The physiological nature of this modality allows potential assessment for functional obstruction and future research on tear flow assessment.

Clinical utility of SPECT/CT and CT-dacryocystography-enhanced dacryoscintigraphy in the imaging of lacrimal drainage system obstruction

Purpose

Epiphora is commonly caused by a relative or complete occlusion in the lacrimal drainage system (LDS), principally a nasolacrimal duct obstruction (NLDO). Dacryoscintigraphy (DSG), an extensively assessed imaging technique in diagnosing its abnormalities, can provide only planar images, according to which it needs to be improved. Our aim was to evaluate clinical utility of simultaneous DSG and single-photon emission computed tomography/computed tomography (SPECT/CT) combined with computed tomographic dacryocystography (CT-DCG) in the evaluation of LDS.

Methods

Dynamic imaging with DSG was performed, and tracer radioactivity was detected by a gamma camera. Successively, SPECT/CT images of the involved region were gained, followed by CT-DCG, during which a contrast medium was syringed into the affected LDS, and finally contrast CT scans were obtained again from the same region.

Results

Fifty-seven patients, mean age 54.25 (± 18.26) years all with unilateral NLDO and 32 control subjects, all with patent LDS, mean age 49.88 (± 18.61) years were evaluated in the study. Delayed outflow of tearing eyes was exposed to DSG compared to the fellow and control eyes. The highest value for sensitivity was observed for SPECT/CT, followed by CT-DCG and DSG techniques, while combining DSG with SPECT/CT, DSG with CT-DCG, and SPECT/CT with CT-DCG, the sensitivity increased to 96.49%, 92.98%, and 94.73%, respectively.

Conclusions

Although DSG is a sensitive nuclear medicine method, it only provides useful clinical data when simultaneously supplemented with SPECT/CT and CT-DCG trials as they jointly can offer valuable information about the localization of an abnormality and verify stenosis or obstruction.

Ocular Biodistribution Studies using Molecular Imaging

Classical methodologies used in ocular pharmacokinetics studies have difficulties to obtain information about topical and intraocular distribution and clearance of drugs and formulations. This is associated with multiple factors related to ophthalmic physiology, as well as the complexity and invasiveness intrinsic to the sampling. Molecular imaging is a new diagnostic discipline for in vivo imaging, which is emerging and spreading rapidly. Recent developments in molecular imaging techniques, such as positron emission tomography (PET), single-photon emission computed tomography (SPECT) and magnetic resonance imaging (MRI), allow obtaining reliable pharmacokinetic data, which can be translated into improving the permanence of the ophthalmic drugs in its action site, leading to dosage optimisation. They can be used to study either topical or intraocular administration. With these techniques it is possible to obtain real-time visualisation, localisation, characterisation and quantification of the compounds after their administration, all in a reliable, safe and non-invasive way. None of these novel techniques presents simultaneously high sensitivity and specificity, but it is possible to study biological procedures with the information provided when the techniques are combined. With the results obtained, it is possible to assume that molecular imaging techniques are postulated as a resource with great potential for the research and development of new drugs and ophthalmic delivery systems.

Usefulness of the dacryoscintigraphy in patients with nasolacrimal duct obstruction prior to endoscopic dacryocystorhinostomy

PURPOSE

To evaluate the clinical usefulness of the dacryoscintigraphy in patients with nasolacrimal duct obstruction prior to endoscopic dacryocystorhinostomy.

METHODS

One hundred thirty-five lacrimal views of endoscopic dacryocystorhinostomy (DCR) with a single surgeon for primary nasolacrimal duct obstruction (PANDO) were included. These were assigned into three groups according to the type of dacryoscintigraphy. Group 1 was a pre-sac obstruction pattern. Group 2 was an intra-sac obstruction pattern. Group 3 was post-sac obstruction pattern. Each group was evaluated for an anatomical and functional surgical success, presence of complications including granuloma, synechiae, and tube-induced inflammation at least 12 months after the surgery.

RESULTS

Both anatomical and functional success rate showed no significant difference among the three groups (P = .297 and .472 linear by linear association). Functional failure rate (functional failure/total failure) also showed no clinically significant differences between groups. Logistic regression analysis was performed to determine the factors associated with functional success. There were no statistically significant factors in age, sex, scintigraphy type, pre-operative endoscopic grade, post-operative granuloma, and synechiae.

CONCLUSION

In patients with nasolacrimal duct obstruction, preoperative evaluation of obstruction level using dacryoscintigraphy may be not useful for predicting the functional success of the endoscopic dacryocystorhinostomy.

Dacryocystography: From theory to current practice

PURPOSE

To provide a review and an update on dacryocystography (DCG) and its relevance in the current era.

METHODS

The authors performed a PubMed search of all articles published in English on DCG, digital subtraction-DCG (DS-DCG), computed tomographic DCG (CT-DCG) and magnetic resonance-DCG (MR-DCG). Data analyzed include the indications, techniques, interpretations, complication and limitations.

RESULTS

Dacryocystography has been used for illustrating the morphological and functional aspects of the lacrimal drainage system (LDS). Subtraction DCG provides the precise location of the alterations and acceptably delineates stenosis or an obstruction. Transit time for contrast into the nose varies widely across the studies. Low osmolality iodinated contrast media are tolerated well for DS-DCG and CT-DCG. However, normal saline either mixed with lidocaine or alone provided similar image quality as obtained with gadolinium for MR-DCG. CT-DCG provides useful information in complex orbitofacial trauma and lacrimal tumors. MR-DCG allows better 3D visualization of the LDS and dynamic functional evaluation. Sensitivity of CT-DCG and MR-DCG are mostly similar in identifying an LDS obstruction.

CONCLUSION

Various forms of DCGs can provide additional information to evaluate patients with maxillo-facial trauma, functional epiphora, suspected lacrimal sac diverticula, partial nasolacrimal duct obstruction, and lacrimal drainage tumors. Canaliculi and the membranous part of the nasolacrimal duct are not yet visualized in detail and further focused studies with advanced techniques are required.

How reliable is the lacrimal scintigraphy report? An inter-observer agreement and reliability study

AIM

To assess the inter-observer agreement and reliability as well as intra-observer repeatability for lacrimal scintigraphy (LS) reports with and without considering the irrigation test results.

METHODS

A prospective, observational, cross sectional study. Two masked clinicians (lacrimal surgeon and nuclear medicine specialist) independently reported 100 LS images (50 patients of >6 years of age with unilateral anophthalmic socket) in a university hospital. The lacrimal surgeon performed a diagnostic irrigation test and repeated the report of the same LS images 2y after the first report (intra-observer agreement). A weighted Kappa analysis was performed to determine inter-observer agreement and reliability as well as intra-observer repeatability for the type (normal, partial and complete obstruction) and location (presac, preduct, and intraduct) of the obstruction. Subgroup analysis was also performed with consideration of irrigation test results.

RESULTS

A significantly moderate agreement was found between lacrimal surgeon and nuclear medicine specialist for both the type (Kappa=0.55) and location (Kappa=0.48) of obstruction. Agreement values were higher for the type (Kappa=0.61 vs 0.41) and location (Kappa=0.56 vs 0.31) of obstruction in cases with normal than abnormal irrigation test. Strong and significant intra-observer (lacrimal surgeon) repeatability was found for both the type (Kappa=0.66) and location (Kappa=0.69) of obstruction. LS showed no to slight reliability based on irrigation test.

CONCLUSION

A moderate agreement is found between lacrimal surgeon and nuclear medicine specialist regarding the interpretation of LS suggesting the importance of consensus groups among nuclear medicine specialists and lacrimal surgeons to create a common language for interpretation of LS. Intra-observer repeatability is strong for the lacrimal surgeon.

Interobserver agreement on interpretation of conventional dacryocystography and dacryoscintigraphy findings: A retrospective single-centre study

IMPORTANCE

This study assesses the interobserver agreement on dacryocystography (DCG) and dacryoscintigraphy (DSG) findings.

BACKGROUND

There are no standard grading criteria to guide the interpretation of conventional DCG and DSG findings and therefore there may be a degree of subjectivity. This study evaluates the level of interobserver agreement in the interpretation of DCG and DSG findings.

DESIGN

A retrospective observational study at the Royal Adelaide Hospital.

PARTICIPANTS

A total of 165 patients who presented with epiphora with 276 DCGs and 290 DSGs performed were included in this study.

METHODS

DCG and DSG images were obtained, anonymized, randomized and interpreted by three independent oculoplastic surgeons. Standard grading criteria were set for both DCG and DSG images. Data from all observers were analysed for interobserver agreement using Kappa (κ) statistics, generated using a variation of Cohen's kappa for multiple observers.

MAIN OUTCOME MEASURES

Level of interobserver agreement (κ values) in the grading of DCG and DSG findings.

RESULTS

There was an overall moderate interobserver agreement for DCG findings (κ = 0.55), with the highest agreement on interpreting canalicular obstruction (κ = 0.80), followed by proximal nasolacrimal duct obstruction (κ = 0.67) and normal patency (κ = 0.63). There was an overall fair interobserver agreement for DSG findings (κ = 0.36), with the best being moderate agreement (κ = 0.42-0.50) for interpreting pre-sac delay and post-sac proximal delay.

CONCLUSIONS AND RELEVANCE

DCG offers good reliability in interpreting patent and obstructed systems. On the other hand, DSG has poor agreement and highlights some of the limitations in the ability to guide epiphora management.

Functional success evaluation of lacrimal drainage system by dacryoscintigraphy after transcanalicular diode laser dacryocystorhinostomy

Purpose:

The purpose of the study was to evaluate the functional success rates using dacryoscintigraphy (DSG) after transcanalicular diode laser dacryocystorhinostomy (TDL-DCR).

Methods:

In this retrospective study, we investigated the records of 56 patients who underwent TDL-DCR for unilateral primary acquired nasolacrimal duct obstruction and anatomic patency was achieved. The lacrimal drainage systems of the other eyes of the patients were normal and were selected as control group. The functional success was evaluated with tear transit time (TT) on DSG and epiphora complaints’ score (ECS) at postoperative 6 months.

Results:

Twenty-two (39%) of the patients were male and 34 (61%) were female, with a mean age of 46.6 (21–64). The dacryoscintigraphic findings of the operated and healthy eyes showed that there was statistically insignificant prolongation in the tear TT at the operated side at postoperative 6^th month (P > 0.05). The mean ECS of operated eyes was 0.89. Functional success was achieved in 43 (76.8%) patients when the ECS of 0 and 1 was accepted as successful. A statistically significant delay in drainage was observed in DSG in all of the cases with epiphora score of 2 and 3 (P < 0.05). The tear TT was prolonged with the age increase (P < 0.05), but there was no significant difference concerning the gender.

Conclusion:

DSG is an effective tool to evaluate the functional success of TDL-DCR.

Dacroscintigraphy by Pediatric Dropper Technique: A User-friendly Instillation Procedure of Radiotracer

Context:

Instillation or application of the radiotracer over the tear film is one of the important parts of dacroscintigraphy. Our study explains the value of an improvised dropper technique so that desired amount of radioactivity in desired volume can be instilled over the tear film.

Aim:

The aim of the study is to introduce a simple and convenient instillation method based on dropper technique for performing dacroscintigraphy. This improvised dropper technique can be used so that desired amount of radioactivity in desired volume can be instilled over the tear film. The objectives of this experiment are to measure the volume and activity of each drop from the dropper.

Settings and Design:

Experiment of volume and activity measurement standardization was carried out in two parts. In the first part, we calculated the volume of each drop indirectly to standardize the volume of drop. In the second part, we standardized the activity in each drop by measuring it in a dose calibrator.

Subjects and Methods:

In this study, we used a common pediatric dropper of approximately 1 ml capacity, radioactivity (^99mTcO4 pertechnetate), sample vial (container), vial holder, a pair of nonsterile gloves, dose calibrator, etc., Experiments of volume and radioactivity standardization were carried out in two parts. The first part of experiment calculated volume of each drop indirectly, and in the second, we standardized the activity in each drop by measuring it in dose calibrator. Statistical analysis used: Analysis of variance test was used to calculate the correlation of readings by same individual as well as among the three individuals

Results:

After analysis of result obtained, it was understood that there was no significant difference found in volume and activity of each drop in the readings recorded by same individual as well as among the three individuals. The calculated activity and observed activity were 86.64 and 79.16 μCi, respectively. The difference was only 8.63% lying within acceptable limits.

Dacryoscintigraphy: A Pictorial Essay

Dacryoscintigraphy is a noninvasive, simple, easy to perform imaging modality used in the evaluation of epiphora. However, it is an infrequently done study in nuclear medicine departments. A standardized protocol and a systematic interpretation of the scans help in answering the queries of the clinicians in cases of epiphora. We have attempted to build a pictorial essay of the various findings detected on dacryoscintigraphy.

External Dacryocystorhinostomy for the Treatment of Functional Nasolacrimal Drainage Obstruction

OBJECTIVES

To determine the outcome and long-term efficacy of external dacryocystorhinostomy (ext-DCR) with or without bicanalicular silicon intubation in patients with functional nasolacrimal drainage obstruction (FNLDO).

MATERIALS AND METHODS

Patients with epiphora and patent lacrimal systems on nasolacrimal irrigation were prospectively enrolled in the study. Each patient was assessed with lacrimal scintigraphy to differentiate drainage abnormalities as presac (proximal) or postsac (distal) delays. All patients underwent ext-DCR; bicanalicular silicone intubation was performed only in presac delay cases. On follow-up examinations patients were asked to report their symptoms as none, mild, moderate or unchanged. Success was defined as lacrimal patency to irrigation and no or mild epiphora at the end of the follow-up period.

RESULTS

Twenty-six lacrimal systems of 23 patients were eligible for inclusion. There were 9 presac delay and 17 postsac delay cases. Average follow-up time was 72.85 weeks (47-88 weeks). A successful outcome was achieved in 76.9% of the operated lacrimal systems. Success rate was 55.5% among presac obstructions and 88.2% among postsac obstructions.

CONCLUSION

The long-term efficacy of ext-DCR in FNLDO patients is confirmed with our overall successful outcome of 76.9%. In preoperative assessment, lacrimal scintigraphy is helpful to determine the surgical approach and to predict the surgical outcome.

The Pre-Sac Reflux Test (PSRT): a new diagnostic test for presaccal stenosis/obstruction

PURPOSE

To introduce a new procedure, the Pre-Sac Reflux Test (PSRT), to screen for epiphora caused by presaccal stenosis/obstruction, and to determine the reliability of this new test in the diagnosis of presaccal stenosis/obstruction.

METHODS

A nonrandomized, prospective, comparative case series of 280 eyes of 140 patients with unilateral presaccal stenosis/obstruction was performed. The PSRT was performed by a masked examiner on both eyes of each patient. After fluorescein staining, the lower lid was everted and lower punctum was observed using a cobalt-blue filter under slit-lamp magnification. After blotting excess fluorescein on the punbtum, the area of lacrimal ampulla was massaged with mild pressure with an index finger. The reflux (billowing of the fluorescein-stained tear) from each lower punctum were compared, and the bilateral symmetry was measured. In the same way, reflux from each upper punctum were compared for bilateral symmetry. The PSRT was considered positive if reflux from punctum was absent, or reduced asymmetrically, compared with that from contralateral punctum. If the test of either upper or lower punctum showed positive, the eye was considered positive. The validity of PSRT was measured by sensitivity and specificity, as well as positive- and negative-predictive values.

RESULTS

The PSRT used to diagnose presaccal stenosis/obstruction has a sensitivity of 92.9 % and a specificity of 97.1 %. It has a positive-predictive value of 97.0 % and a negative-predictive value of 93.2 %.

CONCLUSIONS

The PSRT is a reliable screening test for diagnosis of presaccal stenosis/obstruction.

Dacryoscintigraphic findings in the children with tearing

Purpose

To investigate the diagnostic effectiveness of dacryoscintigraphy in children with tearing; to evaluate tear clearance rate as a diagnostic factor of dacryoscintigraphy in children with tearing; and to analyze the results of treatment according to dacryoscintigraphic findings in children with tearing.

Methods

Between January 2010 and April 2014, 176 eyes of 88 children with tearing (49 boys and 39 girls; mean age, 23.81 ±14.67 months; range, 12 to 72 months) were studied retrospectively. Of these, 37 of 88 children with tearing were bilateral cases, and 51 were unilateral cases. None of the patients had a history of craniofacial disorder or trauma. The chief complaint of tearing with or without eye discharge and delivery mode, past history of neonatal conjunctivitis, syringing, or probing were collected from parents, grandparents, or previous hospital data. The drainage pattern of the nasolacrimal duct was analyzed, and the clearance rate of 50 µCi 99m technetium pertechnetate was measured by dacryoscintigraphy.

Results

According to the dacryoscintigraphy results, 98 of 125 eyes (78.4%) with tearing showed nasolacrimal obstruction and 29 of 51 eyes (56.9%) without tearing showed patency. There was a significant difference between tearing eyes and normal eyes (p = 0.001). The clearance rate difference after 3 and 30 minutes was 16.41 ± 15.37% in tearing eyes and 23.57 ±14.15% in normal eyes. There was a significant difference between epiphoric eyes and normal eyes (p = 0.05). Based on the dacryoscintigraphic findings, nasolacrimal-duct obstruction was treated with probing or silicone-tube intubation. The majority of patients showed symptom improvement (75.2%) during the two months of follow-up.

Conclusions

Dacryoscintigraphy is a non-invasive method of qualitatively and quantitatively diagnosing nasolacrimal duct obstruction in children with tearing.

Lacrimal outflow mechanisms and the role of scintigraphy: current trends

Lacrimal outflow can be compromised by anatomical obstructions or stenoses (nonfunctional epiphora) or by defective lacrimal “pump” function (functional epiphora). Although classic imaging modalities, such as X-ray dacryocystography, computed tomography, or magnetic resonance imaging can effectively evaluate the former, their success is much less in the evaluation of the latter. This is largely due to the fact that forced diagnostic injection of fluid into the canalicular system can overcome partial obstruction sites. On the other hand, lacrimal scintigraphy mimicks “physiological” lacrimal outflow, being performed under pressure gradients present in everyday life. This is why it is considered more suitable for the study of functional epiphora. Furthermore, quantitative lacrimal scintigraphy (with time-activity curves) enables the accurate measurement of lacrimal clearance from the conjunctival fornices and may be used to study the physiology of the lacrimal “pump.” Data obtained from the scintigraphic study of lacrimal outflow may be used to design more effective procedures in the management of functional and nonfunctional epiphora. This is a review article, based on a literature search with emphasis on recent publications and on those supporting interdisciplinary cooperation between ophthalmology and nuclear medicine.

Assessment and management of proximal and incomplete symptomatic obstruction of the lacrimal drainage system

Epiphora is a common complaint of patients who present to an Ophthalmology Clinic. In many cases, epiphora is due to an obstruction in the lacrimal drainage system. However, a subgroup of symptomatic patients with epiphora has a patent lacrimal drainage system. Such cases are usually termed ‘functional obstruction’ and / or ‘stenosis of the lacrimal drainage system’. Various etiologies and diagnostic and therapeutic approaches have been described in literature, which implies the lack of a standardized approach. This article will review the evolving diagnostic and therapeutic approaches in literature, and in the end, propose a paradigm in approaching this group of patients.

Perspective: what does the term functional mean in the context of epiphora?

The term 'functional block' is used to encompass the concept of lacrimal drainage dysfunction in the presence of anatomical patency. There is significant variability in the nomenclature, clinical and investigative criteria used in the literature to define this entity. This has led to confusion and lack of comparability of studies looking at this group. The clinical features, investigative findings and treatment options in this group of patients are described. In addition, the need to differentiate between nasolacrimal stenosis and 'functional block' is emphasized, as evidence suggest patients with nasolacrimal duct stenosis have better outcomes with dacryocystorhinostomy. To better define the disease entity and enable comparability of future studies, it was proposed that this entity be replaced by the term functional epiphora with no delay, pre- or post-sac delay.

Lacrimal scintigraphy: "interpretation more art than science"

Lacrimal scintigraphy (LS) or dacryoscintigraphy can demonstrate abnormalities in 80%-95% of patients with symptoms of epiphora and a patent lacrimal system on syringing and up to 40% asymptomatic individuals. Precise localization of the site of delay may not always be possible due to lack of anatomic detail on LS. LS is considered useful in patients with epiphora with delayed tear clearance and patency to syringing and suspected to have either nasolacrimal duct (NLD) stenosis or lacrimal pump failure. It remains unclear, however, as to whether LS can reliably distinguish between the two. The literature reports considerable variation in the technique, normative data, analysis, and interpretation of LS. Qualitative or visual analysis is simpler to perform and to our knowledge used more frequently in comparison to quantitative analysis. There is little extra information to be gained from LS in cases with complete NLD obstruction or severe NLD stenosis on syringing.

A clinical trial of endoscopic vs external dacryocystorhinostomy for partial nasolacrimal duct obstruction

OBJECTIVE

A literature review revealed there is no outcome data for endoscopic endonasal dacryocystorhinostomy (EES-DCR) in the subgroup of patients with acquired partial nasolacrimal duct obstruction (NDO). This study aimed to compare the results of EES-DCR vs external DCR (ext-DCR) in the treatment of partial NDO.

DESIGN

This study is designed as a prospective nonrandomised comparative clinical trial.

PARTICIPANTS

In total, 46 adult patients with acquired partial NDO participated in this study.

METHODS

Partial (sometimes called 'functional') NDO (epiphora in the presence of patent syringing) was confirmed by nuclear lacrimal scintigraphy or delayed drainage on dacryocystography. Patients with 'functional' epiphora from other causes were excluded. Post-operative outcome was assessed at 6 months. Overall, 21 (46%) patients had EES-DCR and 25 patients had (54%) ext-DCR.

MAIN OUTCOME MEASURES

Subjective success was based on patient symptoms, objective success on patency with syringing and a functioning rhinostomy evaluated using the functional endoscopic dye test (FEDT).

RESULTS

In total 18 out of 21 (86%) of EES-DCR patients had marked reduction (n=11) or complete resolution (n=7) and 25 out of 25 (100%) of ext-DCR had marked reduction (n=9) or complete resolution (n=16) of epiphora. In total 17 out of 18 (94%) of the EES-DCR patients with subjective success had a positive FEDT. All 25 out of 25 (100%) ext-DCR patients with subjective success had a positive FEDT. The three failed EES-DCR patients were all blocked on syringing. Statistically, EES-DCR does not achieve the same success rate as ext-DCR in this study (P=0.09, two-tailed Fisher's exact test, 0.045 one-tailed).

CONCLUSIONS

Both endoscopic and external DCRs provide satisfactory outcomes in acquired partial NDO. The success rate is nevertheless higher in ext-DCR compared with EES-DCR.

A modified Jones test: lacrimal scintigram correlation

PURPOSE

To determine the correlation between lacrimal scintigraphy and a modified Jones primary dye drainage test combined with the fluorescein dye disappearance test (DDT) and Jones secondary dye test, in diagnosing the cause of epiphora.

METHODS

A prospective, consecutive clinical trial was conducted. All patients presenting with epiphora were considered, but those with trichiasis, corneal irritation, lower eyelid ectropion, Bell palsy, or previous lacrimal surgery were excluded. A cohort of 39 patients (65 eyes) underwent the fluorescein DDT and the senior author's (R.B.) modified Jones primary dye drainage test (Jones dye test 1 [JDT1]). For this test, an entire fluorescein 2% Minim dose was instilled in the 2 eyes, and the patient was then asked to gently blow each nostril separately in a white tissue; the degree of fluorescein staining was noted. If there was no fluorescein staining of the tissue (negative JDT1), a traditional Jones secondary dye test (Jones dye test 2) was also performed. All patients except for those testing strongly positive on modified testing or with negative DDT and JDT1 and nil drainage from the nose in Jones dye test 2, indicating anatomical obstruction, were referred for lacrimal scintigraphy.

RESULTS

In total, 59 of 65 eyes (91%) showed a positive correlation between the diagnosis arrived at after dye testing using the modified primary dye test and diagnosis on lacrimal scintigraphy. The interrater reliability for the raters was found to be κ = 0.770 and 95% confidence interval = 0.594-0.945. The strength of agreement is considered to be "good."

CONCLUSIONS

The authors found that in the presence of patent lacrimal drainage system dysfunction, modified Jones primary dye test, combined with the fluorescein DDT and Jones secondary dye test, correlated strongly with lacrimal scintigraphy.

Epiphora: an evidence based approach to the 12 minute consultation

BACKGROUND

Epiphora is the presence of a watering eye which may be due to reflex tearing or defective drainage of tears. Whilst most cases present to the ophthalmologist the otolaryngologist has a key role to play in both assessment and management of these patients.

METHODS

This review was based on a literature search last performed on 21st October 2009. MEDLINE and Cochrane databases were searched using the subject headings 'epiphora' or 'functional epiphora' in combination with diagnosis, investigation, management, treatment, intervention and surgery. Results were limited to English language articles. The personal biographies of the senior authors were also used.

CONCLUSION

An accurate assessment of the site and degree of obstruction is important to ensure the correct management is undertaken. Medical treatment with nasal steroid spray may be effective but the majority of obstructed cases will require surgical intervention in the form of dacryocystorhinostomy (DCR). There is increasing evidence that powered endoscopic DCR has outcomes comparable with the 'gold standard' procedure of external DCR.

Assessment of the accuracy of lacrimal scintigraphy based on a prospective analysis of patients' symptomatology

BACKGROUND

Dacryoscintigraphy is a noninvasive method frequently used for assessment of the lacrimal drainage system. Sometimes conflicting results with patients' complaints are obtained, which have no clear explanation. In our hypothesis, follow-up of patients evaluated with dacryoscintigraphy could be helpful in determining possible explanations for these conflicting results.

METHOD

Thirty-eight consecutive patients (76 eyes) who had not previously undergone dacryocystorhinostomy or probing were entered in the study. Following instillation of 4 MBq (99m)Tc-pertechnetate, a routine procedure of dacryoscintigraphy was performed. After a mean follow-up time of 1.2 +/- 0.3 years (range 0.9-1.6 years), all patients were reassessed clinically.

RESULTS

Using initial patients' symptoms as the gold standard, the sensitivity, specificity, NPV, and PPV of dacryoscintigraphy were calculated to be 82.1%, 75%, 60%, and 90.1%, respectively. The kappa value as a measure of agreement was 0.52. Considering the follow-up study as the gold standard, the sensitivity, specificity, NPV, and PPV were calculated as follows, respectively: 96.3%, 90.4%, 96.3%, and 90.4%. The kappa value was 0.86. There were three initially symptom-free eyes with obstructive pattern on the scans, which developed epiphora on the follow-up. In fact, these eyes were initially classified as false positive, but follow-up assessment showed that they were true-positive scans in a subclinical state.

CONCLUSION

Despite certain drawbacks inherent to the technique, dacryoscintigraphy provides valuable independent information and allows more accurate management decisions. In some patients, data obtained from lacrimal scintigraphy could be predictive, and it makes possible determination of subclinical nasolacrimal duct obstructions.