J Korean Ophthalmol Soc.  2015 Nov;56(11):1699-1705. 10.3341/jkos.2015.56.11.1699.

Measurement of Precorneal Tear Film Using Scheimpflug Camera and Relationship with Parameters for Dry Eye

• Kang NH
• Park YG
• Jun RM

• KMID: 2214177
• DOI: http://doi.org/10.3341/jkos.2015.56.11.1699

Abstract

PURPOSE
To compare the anterior segment parameters including precorneal tear film thickness (PTFT) using Pentacam(R) (Oculus, Wetzlar, Germany) between normal control and dry eye groups and to examine the relationships between the PTFT and other parameters for dry eye.
METHODS
The present study included 23 normal controls (31 eyes) and 25 patients with dry eyes (31 eyes). We compared measurements including PTFT, corneal thickness and astigmatism using Pentacam(R) and analyzed the correlations among the PTFT and fluorescein tear break-up time (FBUT), Schirmer I test (without anesthesia), and ocular surface disease index (OSDI).
RESULTS
The mean PTFT in dry eyes (21.1 +/- 2.0 microm) was significantly thinner than in normal eyes (37.6 +/- 2.0 microm; p < 0.01). In the dry eye group, the corneal thickness was thicker than in the normal eye group but there were no clinically significant differences. The dry eye group experienced more frequent and severe corneal astigmatism compared with the normal group. OSDI scores showed a weak negative correlation with objective clinical measures of dry eye (FBUT, Schirmer I test) but was not statistically significant. However, OSDI was statistically significantly negatively correlated with PTFT (r = -0.46, p < 0.01). The PTFT showed a weak positive correlation with FBUT and Schirmer I test without statistical significance.
CONCLUSIONS
The mean PTFT using Pentacam(R) in the dry eye group was thinner than in the normal group. Additionally, the PTFT was correlated with subjective symptoms. Therefore, the PTFT measurement using Pentacam(R) could be considered a useful method for diagnosis and treatment of dry eye.

Keyword

Dry eye; Fluorescein tear break-up time; Ocular surface disease index; Pentacam(R); Precorneal tear film thickness

MeSH Terms

Astigmatism
Diagnosis
Fluorescein
Humans
Tears*
Fluorescein

Figure

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  Figure 1. Precorneal tear film thickness can be measured by Scheimpflug imaging. (A) The scheimpflug images before and after the fluorescein staining. Note the high-bright visualized tear film (white arrow) and the different optical density of ocular interface (white circle) after fluorescein instillation. (B) Compare 2 image view. The central thickness in the dif-ference A-B section means the thickness of precorneal tear film (black arrow). Only the data presented quality of speciality (black circle) was “OK” were included. We also evaluated the thickness of tear film on temporal, superior, nasal, and in-ferior side and corneal reflective power.

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  Figure 2. The relationship between PTFT and corneal astig-matism. PTFT = precorneal tear film thickness; D = diopter; r = Pearson’s correlation coefficient. * p-value by pearson’s correlation analysis.

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  Figure 3. The relationship among FBUT, Schirmer I test and OSDI. FBUT = fluorescein break-up time; OSDI = ocular surface disease index; r = Pearson’s correlation coefficient. * p-value by Pearson’s correlation analysis.

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  Figure 4. The relationship between the PTFT and parameters for dry eye (FBUT, Schirmer I and OSDI). PTFT = pre-corneal tear film thickness; FBUT = fluorescein break-up time; OSDI = ocular surface disease index; r = Pearson’s cor-relation coefficient. * p-value by Pearson’s correlation analysis.

Reference

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