Evaluating Moisture Migration in Schirmer Test Strips: Exploring Brand-Specific Variations and Introducing Calibration and Conversion Methods

PURPOSE

Schirmer test results are widely used for ocular surface disease assessment, but Schirmer strips are not standardized. We compare the characteristics and tear volume with millimeter moisture migration in different brands of Schirmer strips and introduce methods for volume-based, brand-independent calibration.

METHODS

Physical parameters of Haag-Streit, EagleVision, TearFlo, Contacare, and MIPL/A6 Schirmer strip brands were compared. Schirmer strip millimeter moisture migration distances were assessed 5 minutes after application of incremental microliter volumes of human tears. Linear regression analysis of data points from each Schirmer strip brand was performed, and the root-mean-square deviation of data points to the best-fit linear regression was calculated. Calibration correction was performed by converting migration distance to the corresponding tear volume. A reference table and calibration method formulas were created.

RESULTS

Schirmer strips differed in design, shape, and manufacturing precision. Strip width, weight, and length were different between the 5 brands ( P < 0.05). A wide range of Schirmer strip moisture migration values for identical tear volumes was observed among brands. Statistical measurement resulted in a root-mean-square deviation of 2.9 mm for all data points from all brands. Millimeter to volume and weight to volume-based calibration correction methods resulted in a 2.2- and 3.1-fold measurement error reduction, respectively.

CONCLUSIONS

Our findings highlight the lack of standardization among different brands of Schirmer strips, raising concerns about potential sources of unintentional measurement errors. We propose volume-based Schirmer strip calibration methods and conversion of millimeter to microliter results to achieve brand-independent results and improve Schirmer test accuracy.

Evaluation of Main Lacrimal Gland through Shear-wave Ultrasound Elastography in Patients with Low Schirmer Value

OBJECTIVE

To compare main lacrimal gland values through shear-wave elastography (SWE) in patients with low Schirmer value and unspecified Sjögren's syndrome (SS) with healthy controls.

MATERIAL AND METHOD

Admitted to the ophthalmology department with Schirmer value <10 mm, randomly selected 46 eyes of 46 patients evaluated for Sjögren's syndrome (SS) in the rheumatology department between December 2022 and April 2023 were classified as low Schirmer group (LSG). Randomly selected 48 eyes of 48 patients at a similar age with Schirmer value >10 mm were included as controls. Main lacrimal gland SWE measurements in LSG and control groups were recorded and compared as meter/second (m/sec).

RESULTS

Mean SWE values of the main lacrimal gland were measured as 2.78 ± 0.66 m/sec and 2.26 ± 0.29 m/sec in LSG and controls. SWE measurements were significantly higher in LSG patients than in controls (p<0.001). No significant correlation was found in the analysis between the Schirmer and the main lacrimal gland SWE values in LSG patients (p=0.702, r=0.058). No significant correlation was also detected between the Schirmer and main lacrimal gland SWE values in controls (p=0.097, r=0.242). No significant relationship was also found between age, gender, body mass index (BMI), and SWE values (p=0.351, p=0.493, p=0.328, respectively).

CONCLUSION

Mean SWE value of the main lacrimal gland was determined as significantly higher in patients with aqueous lacrimal insufficiency without SS than in controls. We consider that SWE measurements may be an imaging method to support the diagnosis of aqueous lacrimal insufficiency and used in follow-ups of those with dry eye syndrome (DES) in the future.

Dysbiosis of Ocular Surface Microbiota in Patients With Refractive Allergic Conjunctival Diseases

PURPOSE

We investigated ocular surface microbiota dysbiosis in patients with refractory allergic conjunctival diseases (ACDs; stratified into mild and severe groups) treated with topical tacrolimus.

METHODS

Patients (n = 21) with refractory ACDs (including vernal and atopic keratoconjunctivitis) actively treated with topical tacrolimus and 6 healthy controls were evaluated. Based on clinical scores and expression of specific cytokines on the ocular surface, patients with ACDs were divided into mild and severe groups using cluster analysis. The microbial composition of tear specimens collected from patients with mild and severe ACD and control subjects using the Schirmer test paper was determined through next-generation 16S rRNA sequencing analysis.

RESULTS

Compared with healthy controls, patients with ACDs exhibited significantly decreased ocular surface microbiota α-diversity. Ocular surface microbiota mainly comprised members of the phyla Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria in all groups. The relative abundance of ocular surface microbiota in patients with ACDs was increased for phylum Firmicutes and decreased for phylum Proteobacteria (compared with control subjects). The genera Blautia (vs. mild ACD group) and Morganella (vs. control group) exhibited significantly increased abundance only in the severe ACD group.

CONCLUSIONS

The ocular surface microbiota in patients with severe ACD exhibited decreased diversity and exacerbation of dysbiosis compared with that in patients with mild ACD and control subjects. Patients with mild refractory ACD also exhibited decreased diversity of these microbiota. These alterations in microbiota indicated a change in the ocular surface of patients with refractory ACD (be it because of disease pathogenesis or topical immunomodulatory treatment).

The efficacy and safety of qiming granule in dry eye disease: Protocol for systematic review and meta-analysis

BACKGROUND

Dry eye disease is a common eye disease mainly manifests with eye fatigue, foreign body sensation, dry and astringent eyes and other symptoms. Growing evidence shows that qiming granule may have beneficial effects on the clinical treatment of dry eye disease. However, no systematic review and meta-analysis collate and assess these clinical evidences. The purpose of this study protocol is to provide a comprehensive and reliable evaluation of the clinical evidence of qiming granule in the treatment of DED.

METHODS AND ANALYSIS

Three English database and 4 Chinese databases other sources will be searched. Two methodological trained researchers will read the title, abstract and full texts and independently select the qualified literature according to inclusion and exclusion criteria. After assessment of the risk of bias and data extraction, we will conduct meta-analyses for outcomes including central macular thickness, optimum corrected vision, overall effect rates and adverse effects. The heterogeneity of data will be investigated by Cochrane X and I tests. We build 3 hypotheses for subgroup analysis according to the guidance for a credible subgroup effect: Disease status at baseline, duration of intervention, type of concomitant medication. Sensitivity analysis will be conducted to evaluate the stability of the results. Then publication bias assessment will be conducted by funnel plot analysis and Egger test. Finally, we will use the Grading of Recommendations Assessment, Development and Evaluate system to evaluate the quality of evidence.

RESULTS

The results of our research will be published in a peer-reviewed journal.

CONCLUSION

Our study is the first meta-analysis to evaluate the clinical efficacy and safety of qiming granule in the treatment of DED. It will provide more options for clinical treatment of the disease.

PROSPERO REGISTRATION NUMBER

CRD42018109183.

Evaluation of Phenol Red Thread test versus Schirmer test in dry eyes: A comparative study

BACKGROUND

Dry eye is the most common ocular morbidity found in elderly patients. There is no gold standard/standard test for diagnosing dry eye.

OBJECTIVES

The present study was conducted to compare the potential of Phenol Red Thread (PRT) test versus Schirmer Test in diagnosing dry eye.

MATERIALS AND METHODS

The study was conducted on 50 patients, aged 40 years and above. History of dry eye symptoms was taken and the symptoms were graded. Six-questions Bandeen Rosch questionnaire was administered to those having symptoms of dry eye. Patients whose response to any of the questions was often/all the time were included in the study. After performing standard clinical examination, Schirmer and PRT tests were done.

RESULTS

PRT is equally sensitive in detecting dry eye, and in addition, it has many advantages as compared to Schirmer. PRT is simpler and more comfortable to the patient and can be done in children. It causes less reflex tearing. Most important is the lesser time consumed (15 seconds) in comparison to Schirmer (5 minutes).

CONCLUSION

Kappa value between PRT and Schirmer was found to be 0.96 in this study and shows a strong agreement between the two. So, PRT can be considered equally good in detecting dry eye.