Temporary Dry Eyes Caused by Eating Fried Foods ^†

Abstract

Tear osmotic pressure, tear volume, and quality were measured before and after subjects without dry eye syndrome ate fried chicken slices for one week. By analyzing the data, we explored the causes of temporary dry eye syndrome. A 2 mL volume of normal saline was added to fluorescent tear test paper, which was applied to the conjunctiva of the subject, and the tear breakup time and tear lake height were measured with a digital slit lamp. The tear test paper was placed on the outside of the subject’s lower eyelid to test their tear volume. A total of 29 subjects, aged between 20 and 55 years old, ate fried foods for one week. The amount of tears produced before and after they ate fried chicken slices was tested using paired samples t-tests. The tear volume in the left and right eyes decreased at a significance level of p < 0.05. The tear membrane breakup time before and after treatment was analyzed using fluorescent reagents and digital slit lamps. The paired-sample t-test results showed that there was a statistically significant difference (p < 0.05). Eating fried chicken slices for a week significantly contributed to dry eyes, regardless of gender and age.

1. Introduction

Technology has developed, bringing great convenience to people’s lives. In today’ environment, multimedia computers, communication technologies, and consumer electronics are used everywhere, especially smartphones, which are always in hand, with individuals having an average usage time of more than ten hours. When an individual is staring at a phone screen, their tears cannot be secreted normally, and their tears can evaporate relatively quickly, resulting in significant dry eye symptoms. Dry eyes can cause soreness, itchiness, swelling, redness, and blurred vision, seriously affecting visual quality. “Dry eyes” are one of the most common diseases seen in ophthalmology clinics; it is mainly caused by reduced tear secretion, uneven tear distribution, or excessive tear evaporation, resulting in an inability to keep the surface of the eyeball moist with tears [1,2,3,4,5,6]. Dry eyes are a serious public health problem, affecting 23.7 to 33.7% of the population. In those suffering from dry eyes, the cornea is prone to inflammation, and in severe cases, this may even cause corneal and conjunctival lesions, affecting vision.

Fried chicken slices are a common and popular snack in Taiwan. Long-term consumption of fried food can lead to dry eye syndrome. However, no research has been conducted to explore whether the short-term consumption of fried foods can cause dry eyes. Therefore, we conducted eye examinations, using ophthalmic instruments, on consumers who ate fried chicken slices for a week to confirm that fried foods can cause dry eyes.

2. Research Principles

The human tear system consists of the primary lacrimal gland, the accessory lacrimal gland, the tear film, the inferior lacrimal puncta, the superior lacrimal puncta, the lacrimal sac, the nasolacrimal duct, and the nasolacrimal duct. The lacrimal glands include the lacrimal gland and accessory glands (Figure 1). The accessory lacrimal glands include Krause and Wolfring glands. The secondary glands include goblet cells that secrete mucin on the conjunctiva, as well as the Tarasal glands and glands of Zeis, which secrete oil [7,8]. Tears are mainly supplied by accessory glands and secondary glands. This layer of tears is applied on the surface of the eye to help lubricate the eyeball and maintain the health and comfort of the eye. When the lacrimal gland secretes too few tears, which evaporate too quickly, the ocular surface is not lubricated enough, and the epidermal cells of the conjunctiva and cornea can dry out and fall off, or even become inflamed. This phenomenon is called dry eye syndrome. Dry eyes or insufficient tear production stimulates reflex tear secretion and causes frequent tearing [9,10].

Five different ophthalmic test methods were used to measure the tears of subjects before and after short-term consumption of fried foods. The results were analyzed using paired-sample t-tests and linear regression analysis, and the values of various related parameters were compared and analyzed. In the statistical analysis, when the p-value was less than 0.05, the result was regarded as statistically significant. Descriptive statistics refers to the description of aggregated data using tables for classification, graphics, and calculations, mainly including frequency analysis, central tendency analysis, dispersion analysis, and distribution of data, as well as some basic statistical graphics.

Adequate production, retention, distribution, and balanced drainage of tears are essential for the health and normal function of the ocular surface. Any imbalance in these components can cause dry eyes. Tear osmolarity is the end product of changes in tear dynamics, and is the only biophysical measurement that tests the balance of tear film input and output dynamics. Normal intraocular balance requires the regulation of tear flow, and osmolarity is the primary driver of tear flow regulation. Therefore, high osmolarity is an important biomarker for dry eyes.

3. Experimental Results

Figure 2 shows a block diagram of the experimental system used in this study, which comprised four types of measurement equipment: a tear test strip, a digital slit lamp, a keratometer, and a tear osmolarity system. The production process for the fried chicken slices used in the experiment was as follows: Low-gluten flour and corn flour were mixed in a ratio of 3:1 to make a frying powder, then egg white and water were added and the batter was mixed well.egetables and fruits were cut into pieces, and the meat was marinated; all ingredients were cut into small pieces or slices to avoid the food being difficult to fry. After coating the ingredients with batter, they were fried in a pan. The oil temperature in the pan used for frying French fries was maintained at 180 °C. The corneal curvature data obtained with the keratometer was used to determine whether the subject’s astigmatism was corneal astigmatism or axial astigmatism, and whether the myopic structure was refractive or axial, so as to determine whether each subject needed to wear hard or soft contact lenses.

The more accurate the measurement and analysis of the astigmatism parameters of the subject’s eye are, the more comfortable and clear their glasses or contact lenses will be. A digital slit lamp is a combination of a microscope and lighting that is used by an ophthalmologist to see the inside and outside of subject’s eye in 3D. It is used along with an ophthalmoscope to view the back of the subject’s eye. It consists of a binocular microscope that can be moved forward, backward, left, and right on a base, a light source with adjustable brightness, and a frame that allows the subject to rest their head during the examination in order to keep their head stable during the test. Tear test strips were used to test tear secretion. For this test, anesthetic eye drops were dropped onto the surface of the subject’s eye. After waiting for a few minutes, the tear secretion test strip was placed on the inner corner of the eye. The subject closed their eyes for 5 min, the filter paper was allowed to absorb the tears, and then the filter paper was removed and the amount of filter paper wetted by the subject’s tears was measured to estimat the subject’s tear flow production. If the tear flow distance on the test strip was less than or equal to 5 mm, the subject was identified as likely to have dry eyes. If the tear flow distance was less than 5 mm and the corneal staining test was positive (+), the subject was identified as already having dry eyes.

The new osmometer used for testing was a “lab-on-a-chip” based osmometer that employs electrical impedance and uses less liquid, requiring only 50 nanoliters of tear fluid. The test card was inserted into a “pen-shaped” holder and gently placed on the tear film for about 30 s. It was then inserted into a portable desktop device to calculate and display the osmotic pressure test results. The reader automatically converted the tear sample data into an osmotic pressure measurement. This rapid method of obtaining osmotic pressure promotes the application of osmotic pressure determination in clinical practice.

The entire experimental process is shown in Figure 3, including the recording of basic eye physiological information of healthy subjects, the five eye physiological parameter tests carried out before the subjects ate the fried chicken slices, the five eye physiological parameter tests carried out after the subjects ate the fried chicken slices, data statistics and analysis, and the diagnosis of dry eye syndrome [11,12].

• Fluorescent tear fluid reagent was added to an appropriate amount of saline solution, and about one third of the outer side of the lower eyelid of the examinee was used to test their tear volume. Without anesthesia, after 5 min, the digital slit lamp was used to observe the tear flow distance of the subject, as indicated by the fluorescent reagent. The value was required to no less than 10 mm.
• A test strip was placed in the tear meniscus of the lower eyelid, and the tear osmolarity was measured using a tear osmolarity system.
• An appropriate amount of fluorescent reagent diluted in saline solution was applied to the conjunctiva. A digital slit lamp was used to observe and record the tear breakup time (TBUT).
• Fluorescent reagent diluted with saline was instilled on the solution conjunctiva. After the subject blinked, the digital slit lamp was used to observe and measure the height of the tear meniscus.
• Keratometry was performed while the subject blinked and focused on a target object in order to evaluate tear breakup time.

We measured and analyzed subjects’ tears before and after they eat fried foods. A total of 29 subjects, 18 men and 11 women, aged from 20 to 55 years old, ate fried foods for one week. Five different testing methods were used to compare and analyze various eye physiological parameters. Before subjects ate the fried chicken slices, the physiological parameters were as follows: For osmotic pressure, the average value was 310.30 mOsm, and its standard deviation (SD) was 18.98 mOsm; the maximum value (Max) was 346.00 mOsm, and the minimum value (Min) was 275.00 mOsm. For the tear film breakup time (BUT), the average value was 15.73 s, and its SD was 10.24 s; its Max and Min values were 48.00 and 4.00 s. The average BUT was 12.32 s; its SD, Max, and Min were 5.22, 25.00, and 5.00 s. The average, SD, Max, and Min were 1.50, 0.39, 2.50, and 1.00 mm, respectively. The tear lake height was tested using tear test paper, and the average, SD, Max, and Min were 18.57, 10.85, 35.00, and 2.00 mm, respectively.

Table 1. Physiological parameters before subjects ate fried chicken slices.

Parameter	Average	SD	Max	Min
Tear osmotic pressure (mOsm)	310.30	18.98	346.00	275.00
BUT of corneal curvature (s)	15.73	10.24	48.00	4.00
Tear film breakup time (s)	12.32	5.22	25.00	5.00
Tear lake height(mm)	1.50	0.39	2.50	1.00
Tear test strips (mm)	18.57	10.85	35.00	2.00

shows the statistical analysis of the eye physiological parameters before subjects ate the fried chicken slices.

One week after the subjects ate the fried chicken slices, the individual test results were as follows: the average, SD, Max, and Min osmotic pressure were 314.18, 19.29, 355.00, and 277.00 mOsm. The average, SD, Max, and Min BUT of corneal curvature were 9.39, 4.40, 20.00, and 3.00 s. As measured by the slit lamp test, the average, SD, Max, and Min BUT were 9.14, 5.22, 25.00, and 5.00 seconds of tear film breakup time. The average, SD, Max, and Min for tear height were 1.17, 0.32, 2.00, and 0.50 mm. The tear test paper test results showed that the average, SD, Mix, and Min for tear height were 14.59, 11.04, 35.00, and 2.00 mm. The subjects experienced temporary dry eyes after eating fried food for one week, proving that long-term consumption of fried food might be harmful to human eyes.

Table 2. Physiological parameters after subjects ate fried chicken slices.

Parameter	Average	SD	Max	Min
Tear osmotic pressure (mOsm)	314.18	19.29	355.00	277.00
BUT of corneal curvature(s)	9.39	4.40	20.00	3.00
Tear film breakup time (s)	9.14	5.22	25.00	5.00
Tear lake height (mm)	1.17	0.32	2.00	0.05
Tear test strips (mm)	14.59	11.40	35.00	2.00

shows the analysis results of the five eye physiological parameters after subjects ate the fried chicken slices.

4. Conclusions

In this study, we analyzed the physiological parameters of the subjects’ eyes before and after they ate fried chicken slices. All the results were significant, as their p-values were less than 0.01. The tear film breakup time of subjects before and after they ate fried chicken slices for one week was measured using a digital slit lamp. The paired-sample test results showed a significant difference at p = 0.006. The tear osmotic pressure system was used to analyze subjects’ tear osmotic pressure before and after they ate fried chicken slices. The paired sample t-test results showed a significant difference at p = 0.036. Subjects’ tear lake height was measured using a digital slit lamp before and after they ate fried chicken slices for one week. The paired sample t-test showed a significant difference at p = 0.01. The subjects reported that long-term consumption of fried chicken slices caused dry eyes. In this study, it was verified that short-term consumption of fried foods for a week caused dry eyes. Given that 3C products have been in use for a long time, eating fried chicken slices while using these products could harm eye health significantly.