Abstract
Purpose:
To determine the diagnostic accuracy of manual regurgitation on pressure over the lacrimal sac (ROPLAS) versus lacrimal irrigation for screening nasolacrimal duct obstruction (NLDO) in adults prior to intraocular surgeries.
Methods:
This cross-sectional study took place in a tertiary eye care hospital in South Tamil Nadu, India. From January to December 2017 and included consecutive patients who presented for routine cataract surgery. Prospective data collection occurred in 8369 eyes of patients who underwent cataract surgery. All patients underwent ROPLAS testing by an ophthalmologist followed by lacrimal irrigation by trained ophthalmic assistants, rechecked or confirmed in equivocal cases by ophthalmologists who were masked to the ROPLAS status. The primary outcome, the sensitivity, specificity, positive, and negative predictive values to detect lacrimal occlusion by ROPLAS compared with lacrimal irrigation with 95% confidence intervals was estimated.
Results:
A total of 8369 eyes underwent cataract surgery during the time periods of the study. ROPLAS and lacrimal irrigation were performed in all eyes. The sensitivity of ROPLAS to diagnose NLDO correctly was 54.5% (95% CI, 44.8%–63.9%) and its specificity was 100% (95% CI, 100%–100%). The positive and negative predictive values were 75.3% (95% CI, 65.6%-83.0%) and 99.4% (95% CI, 99.2%–99.5%), respectively.
Conclusion:
We found that ROPLAS when used alone had very low sensitivity and low positive predictive value in detecting NLDO prior to cataract surgery as compared with lacrimal irrigation. Hence, we recommend performing ROPLAS and lacrimal irrigation in every patient as part of the routine preoperative workup prior to cataract surgery.
Keywords: Intraocular surgeries, lacrimal obstruction, ROPLAS, syringing
Nasolacrimalduct obstruction (NLDO) is a well-established risk factor for postoperative endophthalmitis following cataract surgery.[1,2,3] An obstructed nasolacrimal duct not only leads to persistent tearing and discomfort in patients but also predisposes to conjunctival colonization by pathological bacteria and an increase in the number of conjunctival commensals.[4] In view of these sequelae, it becomes imperative to check for NLDO prior to cataract surgery.
Tests used to check for occlusion of the lacrimal passage include manual regurgitation on pressure over the lacrimal sac (ROPLAS), lacrimal irrigation with saline, Jones 1 and Jones 2 tests, fluorescein dye disappearance test, themicroreflux test, nasal endoscopy, contrast dacryocystography (macrodacryocystogram or MCDG), dacryoscintigraphy and radiological studies using computed tomography and magnetic resonance imaging (CT and MRI) Jones 1 and 2 testing and the dye disappearance test are limited because of their inability to estimate the level of obstruction CT and MRI are used mostly in craniofacial deformities, after craniofacial injury and suspected neoplasia.[5,6,7] Diagnostic accuracy of MCDG is definitely better than lacrimal irrigation.[8] Accessibility and economic constraints limit their use in community settings. In India, the patency of the lacrimal passage is usually evaluated by ROPLAS or lacrimal irrigation in outpatient clinics. ROPLAS is noninvasive, produces minimal patient discomfort, and is easy to perform in the outpatient setting. Lacrimal irrigation involves irrigation of the lacrimal sac using a lacrimal cannula inserted via the puncta and canaliculi. It is invasive and hence associated with greater patient discomfort. Given these disadvantages, there is reluctance to subject every patient to lacrimal irrigation before cataract surgery. A survey conducted by Nair et al.[6] in 2015 included a large number of oculoplastic specialists in India, where the majority of respondents (60%) felt that ROPLAS was sufficient to test for NLD occlusion prior to cataract surgery. Only 30% respondents felt the need to do routine lacrimal irrigation in all patients. Though authors reveal the preferences of respondents, they do not provide reasons as to why majority did not prefer lacrimal irrigation. Another study deemed that preoperative lacrimal irrigation was unnecessary unless the findings of ROPLAS were equivocal or the index of suspicion for chronic dacryocystitis was very high.[9]
ROPLAS test results are usually positive only in infected nasolacrimal duct obstruction with mucopurulent material in the lacrimal sac.[7] While checking for NLD patency by ROPLAS alone has its advantages, sensitivity of this diagnostic test was not found to be sufficiently high enough to rule out NLD obstruction.[9] Moreover, there are not many studies that have compared the sensitivity and specificity of ROPLAS versus lacrimal irrigation to detect NLD obstruction. We performed this study to compare the ability of the ROPLAS test versus lacrimal irrigation as a diagnostic tool for NLD obstruction in more than 8000 patients scheduled to undergo cataract surgery. Lacrimal irrigation was considered as the reference standard for detecting NLD obstruction in this study.
Methods
This was a cross-sectional study conducted from January to December 2017 at a tertiary eye care center including consecutive patients who presented for routine cataract surgery. All patients with active infections like acute conjunctivitis, acute uveitis, acute glaucoma, acute dacryocystitis, patients less than 16 years of age, and patients with previous history suggestive of NLD trauma were excluded from the study. The study was approved by the local institutional ethics committee and was conducted as per the tenets of the Declaration of Helsinki. Informed consent for lacrimal irrigation was obtained from all participants as part of the procedures prior to undergoing cataract surgery.
Consecutive patients presenting to the outpatient clinic, diagnosed to have cataract, and willing to undergo cataract surgery were included in the study. Patients were initially examined by an ophthalmologist for ROPLAS. For ROPLAS testing, the anterior lacrimal crest was identified by tracing the inferior orbital margin medially and superiorly. The index finger was then directed behind the crest and used to apply pressure on the sac area in an upward and medial direction so as to express the contents of the lacrimal sac into the conjunctiva. Any reflux of fluid, clear, mucoid, or purulent material from the puncta was noted. Those with clear, mucoid, or purulent regurgitation from either one or both puncta during ROPLAS were considered positive for NLD obstruction. Following this, a detailed examination of the anterior segment and fundus was done on the slit lamp. Lacrimal irrigation was carried out in a different room by a trained ophthalmic technician who was unaware of the ROPLAS status. For lacrimal irrigation, the patient was placed in a supine position and topical anesthetic (4% lignocaine) placed in the eye. The lower punctum was dilated with a punctum dilator and lacrimal irrigation was done from the lower punctum using a 27-gauge bent cannula. At the time of lacrimal irrigation, those who reported fluid into the nasopharynx were considered to have a patent NLD. Those with any regurgitation of fluid, including clear, mucoid, or purulent regurgitation from the opposite punctumon lacrimal irrigation without any fluid passage into the nasopharynx were considered to have NLD obstruction. Those with regurgitation through the same punctum from both puncta were considered to have canalicular obstruction. Those who developed a sac swelling post lacrimal irrigation and fluid went into the nasopharynx after compression of the swelling were considered to have atonic sac. All doubtful or equivocal cases were cross-checked by an ophthalmologist.
These cases were then compared for their findings of the ROPLAS status and lacrimal irrigation. Those with 1) positive ROPLAS and NLD obstruction, 2) negative ROPLAS and NLD obstruction, and 3) atonic sacs were taken up for dacryocystorhinostomy (DCR) with deferral of cataract surgery. All those with a negative ROPLAS with canalicular obstruction or patent NLD on lacrimal irrigation underwent routine cataract surgery with preoperative antibiotic regimen as followed at the institute.
Statistical analysis
Continuous variables were presented as mean with standard deviation and categorical variables were presented as proportions (n, %). The status of the NLD on lacrimal irrigation was considered as reference standard for its patency. The primary outcome, the sensitivity and specificity to detect NLDO by ROPLAS compared with lacrimal irrigation along with 95% confidence interval were estimated. Data were entered into Microsoft Excel and analyzed using STATA 12.1 I/C (Fort Worth, Texas, USA).
Results
A total of 8323 eyes of patients who underwent cataract surgery were included in this study. The mean age of patients was 62 ± 9.2 years and 23% (1914) were men. A total of 61 patients with positive ROPLAS and regurgitation on lacrimal irrigation through opposite punctum were diagnosed as NLDO. In 20 patients with negative ROPLAS, lacrimal irrigation was used as a sac swelling and was reported free after compression of the sac. These were diagnosed with an atonic lacrimal sac. A total of 51 patients with a negative ROPLAS and regurgitation of fluid through opposite punctum were also diagnosed as NLDO. In all these 132 patients, cataract surgery was deferred and DCR was carried out. All other patients underwent cataract surgery. Table 1 shows the details of diagnosis and management of patients according to ROPLAS and lacrimal irrigation status.
Table 1.
Diagnosis and management details based on the ROPLAS and lacrimal irrigation status comparison of ROPLAS testing with duct syringing
| ROPLAS | Lacrimal irrigation | Surgery |
|---|---|---|
| Positive | Regurgitation of clear fluid/mucous/pus through opposite punctum | DCR |
| Negative | Regurgitation of clear fluid/mucous/pus through opposite punctum | DCR |
| Negative | Patent after compression of sac swelling | DCR |
| Negative | Free/patent | Cataract extraction |
| Negative | Regurgitation of clear fluid through same punctum | Cataract extraction |
| Negative | Punctum not seen | Cataract extraction |
Table 2 gives the details of comparison of ROPLAS testing with lacrimal irrigation. The sensitivity of ROPLAS to diagnose NLD obstruction correctly was 54.5% (95% CI, 44.8%–63.9%) and its specificity was 100% (95% CI, 100%–100%). The positive and negative predictive values were 75.3% (95% CI 65.6%-83.0%) and 99.4% (95% CI, 99.2%–99.5%), respectively. Table 3 gives the statistical analysis of ROPLAS testing.
Table 2.
Comparison of ROPLAS testing with duct syringing
| ROPLAS | Lacrimal Syringing | ||
|---|---|---|---|
|
| |||
| Regurgitation of clear, mucoid or purulent material through opposite punctum | No regurgitation/Patent | Total | |
| Positive | 61 | 0 | 61 |
| Negative | 51 | 8211 | 8262 |
| Total | 112 | 8211 | 8323 |
Table 3.
ROPLAS testing for detecting chronic dacryocystitis: Statistical analysis
| Result | Percentage | 95% Confidence interval |
|---|---|---|
| Sensitivity | 54.5 | 44.8-63.9 |
| Specificity | 100.0 | 100.0-100.0 |
| Positive predictive value | 75.3 | 65.6-83.0 |
| Negative predictive value | 99.4 | 99.2-99.5 |
Discussion
In this study from a large cohort of patients scheduled to undergo cataract surgery, we found that the ROPLAS test had a low sensitivity and high specificity of detecting NLDO. The treatment for those found to have NLDO was stratified depending on the results of lacrimal irrigation and ROPLAS. None of the study participants developed acute postoperative endophthalmitis.
There has been controversy on the need for routine lacrimal irrigation prior to cataract surgery to assess the patency of the NLD. In an influential paper in 1997, Thomas et al.[9] evaluated the sensitivity and specificity of ROPLAS as a screening test for chronic dacryocystitis and compared it with lacrimal irrigation in 621 consecutive outpatients who needed lacrimal irrigation for various reasons. Out of these 621, only 318 (51%) patients were scheduled for cataract surgery. Authors reported a moderate sensitivity and specificity of ROPLAS of 85.7% and 99.0%, respectively. They concluded that in view of the opportunity costs, when ROPLAS is negative, preoperative lacrimal irrigation in cataract is perhaps unnecessary. However, we found a much lower sensitivity of ROPLAS was 54.5% with the highest possible sensitivity being only 63.9% in 95% cases. A diagnostic test with a low sensitivity will have a high level of false negative rate meaning that when ROPLAS was negative, the patient may be misclassified as not having NLDO in 45.5% of patients that have NLD obstruction.
In our study, we had a high specificity of 100% similar to the study by Thomas et al.[9] High specificity of a screening test indicates that if ROPLAS is positive, chronic dacryocystitis is almost definitely present.[9]
The PPV in our study was 75.3% (95% CI, 65.6%-83.0%) and NPV was 99.4%( 95% CI, 99.2-99.5%) which was similar to the analysis of cataract surgery patients without lacrimal complaints where PPV was 75% and NPV was 99.5%in the study by thomas et al.[9] This signifies when ROPLAS positive in cataract surgery patients, there is only 75.3% possibility that patient has been correctly identified for having NLDO. The prevalence of chronic dacryocystitis in our study was 1.35% where as in the study by Thomas et al.,[9] it was found to be around 6.6%. This was probably due to the fact that the study by Thomas et al.,[9] included patients with complaints of epiphora, corneal ulcers, and routine cataracts where as in our study included cataract surgery patients only. Even though NPV is high, as there are chances of missing out on true positives, there is the increased possibility of developing postoperative endophthalmitis. We recommend routine preoperative lacrimal irrigation along with ROPLAS in cataract surgery patients.
Diagnostic tests form a part of the diagnostic strategy. They gain more value in our decision making if they give extra information, which may result in definitive diagnosis, improved treatment planning, and outcomes. For example, lacrimal irrigation might be a better tool in diagnosing atonic sac cases as compared with ROPLAS. Another major advantage of lacrimal irrigation is its ability to give knowledge regarding the site of obstruction in the nasolacrimal drainage system, which will help the ophthalmologist to refine his treatment planning [Table 1]. This gives more impetus to our argument that ROPLAS and lacrimal irrigation together may be made as routine preoperative diagnostic tests to be carried out before cataract surgery.
There is very limited literature exploring this important question of whether ROPLAS alone can be used to assess NLD patency prior to cataract surgery. In a study from India, Bhimshetty et al.[10] studied patients scheduled for cataract surgery and performed lacrimal irrigation in 1255 patients who were ROPLAS negative and found NLD obstruction in 45 patients, of which 11 had purulent regurgitation. Authors concluded that even if ROPLAS is done by personnel it is possible to miss the patients with NLDO and thus ROPLAS is not as safe and effective method as lacrimal irrigation in community setting. We found similar results and draw similar conclusions in a bigger sample set.
In another study from India, Alam et al.[11] studied correlation of self-ROPLAS by patients and the presence of NLDO diagnosed by physicians. A total of 134 patients were studied, with history of self-ROPLAS present in 64 patients, whereas the physician examination revealed ROPLAS to be positive in 92 patients. All patients with a positive history of self-ROPLAS had NLDO on subsequent examination. They concluded that self-ROPLAS is a simple and effective clinical screening tool for diagnosing NLDO, especially in developing countries. This is consistent with the high specificity rate of ROPLAS being associated with NLDO finding as noted in our study as well. This study also mentions situations when ROPLAS can be negative even in the presence of NLDO, like when it is not done correctly, or in cases of encysted mucocele, fibrosed lacrimal sac, or if the patient has emptied the sac him/herself just before the examination.[11] These reasons are most likely the cause of low sensitivity rate of ROPLAS as noted in our study.
Microreflux test (MTS) has been mentioned in a study by Camara et al.,[7] where the test was considered positive if there was continued observed reflux of fluorescein-stained tears from the inferior punctum after the initial counter clock wise massage to empty the inferior canaliculus after 0.25% sodium fluorescein dye instillation in the inferior cul de sac. According to the authors, the test was highly sensitive and specific for detection of primary acquired nasolacrimal duct obstruction (PANDO). More studies comparing MTS with PANDO could be of benefit and maybe we could substitute ROPLAS testing with microreflux testing for predicting duct blockage.
The drawbacks of the study were that both ROPLAS and lacrimal irrigation were done on the same day, which could potentially influence outcomes. The strength of this study is the large sample size.
Conclusion
In conclusion, we found that ROPLAS when used alone had a very low sensitivity and low positive predictive value in detecting NLDO prior to cataract surgery as compared with lacrimal irrigation. Hence, we recommend performing ROPLAS and lacrimal irrigation in every patient as part of the routine preoperative work up prior to cataract surgery.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
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