Study Design

The study was approved by the Institutional Review Board of Ehime University (No. 0701006) and University Hospital Medical Information Network Clinical Trials Registry (ID number UMIN000004256). An informed consent for the examinations was obtained from all subjects, and the procedures used conformed to the tenets of the Declaration of Helsinki. This was a prospective, cross-sectional study designed to determine the relationship between eyelid pressure during blinking and the fluorescein staining of the cornea and conjunctiva in dry eye patients.

Subjects

The eyelid pressure was measured in 130 eyes of 65 dry eye patients and 58 eyes of 31 normal controls between March 2008 and November 2008 at the Ehime University School of Medicine. The dry eye group (D group) consisted of 13 men and 52 women whose average ± standard deviation age was 58.7 ± 15.0 years with a range from 19 to 91 years. The normal control group (N group) consisted of 14 men and 17 women whose average age was 51.1 ± 17.3 years with a range from 20 to 85 years.

Dry eye was diagnosed according to the 2006 revised Japanese Dry Eye Diagnostic Criteria. The revised criteria for dry eyes were: (1) presence of dry eye symptoms; (2) presence of either qualitative or quantitative disturbances of the tear film (Schirmer I test ≤5 mm or fluorescein tear break-up time [BUT] ≤ 5 s); and (3) presence of conjunctivocorneal epithelial damage (fluorescein staining score ≥3 points or rose bengal staining score ≥3 points or lissamine green staining score ≥3 points). The presence of all 3 criteria is required to establish a diagnosis of definite dry eye. Individuals with 2 positive criteria among the 3 are diagnosed with probable dry eye. Individuals with the presence of either 1 or no positive criteria are diagnosed as normal.

Cases of allergic conjunctivitis, eyelid closure failure, deformed eyelids, conjunctival concretion, or abnormal blinking disorders and cases with a history of any type of eye surgery were excluded. The differences in the age and sex distribution in the N and D groups were not significant.

Eyelid Pressure Measurements by Blepharo-tensiometer

We developed a simple and easy-to-use eyelid pressure measurement system using tactile pressure sensors (DigiTacts Single Point Sensors; Pressure Profile Systems, Inc, Los Angeles, California, USA). The pressures of the upper and lower eyelids were measured using the same sensor for each subject, as described in detail. Briefly, a sterile disposable soft contact lens (Focus Dailies -3.0 diopter; Chiba Vision, Duluth, Georgia, USA) was placed on the cornea after the eye was anesthetized with topical 0.4% oxybuprocaine (Santen, Osaka, Japan) to protect the cornea. The pressure sensor with the protective polyurethane cap (Okamoto, Tokyo, Japan) was inserted between the soft contact lens and the inner surface of the eyelid. The sensor was placed at the center of the upper eyelid and at the nasal region of the lower eyelids. The subjects were asked to close their eyes and keep their eyes closed for at least 5 seconds for the measurements. The measured pressure was divided into 2 phases: an increasing phase and a plateau phase. Then 2 best-fitting lines were drawn to fit the 2 phases, and the intersecting point was determined. The eyelid pressure was defined as the average of 150 tension values obtained during the 5 seconds after the intersection point. An ophthalmic technician was trained on the protocol for measuring the eyelid pressure, and after she became proficient with the device, she was instructed to perform the measurements.

Evaluation of Ocular Surface Staining

After instillation of 2 μL of 1% fluorescein Na solution into the cul-de-sac, the location and degree of the ocular surface staining were determined by slit-lamp microscopy with a yellow stop filter (Carl Zeiss Meditec, San Francisco, California, USA). The cornea and conjunctiva were divided into 7 sections ( Figure ), and the ocular surface staining was scored in each area on a scale of 0–3. Examples of the ocular surface staining scores are shown in the Figure . The corneal fluorescein staining was denoted as KFS while that of the conjunctiva was denoted as CFS. The ocular surface staining was evaluated before eyelid pressure measurements.

Location and degree of ocular surface staining by fluorescein. (Left) Cornea and conjunctiva are divided into 7 sections. (Right) Examples of ocular surface staining scores. KFS = corneal (kerato) fluorescein staining; CFC = conjunctival fluorescein staining. ∗: Excluded from the analysis because fluorescein staining scores in these areas were negligible.

Evaluation of Other Factors Used to Assess Ocular Surface

We calculated the correlations between the location and scores of the ocular surface staining and other factors used to assess the condition of the ocular surface. These factors included the Schirmer I test scores (mm), fluorescein tear film BUT, meibomian gland dysfunction (MGD; grade 0–3 after Shimazaki and associates ), tear meniscus height (TMH; low/medium/high), superior conjunctivochalasis (grade 0–3 after Yokoi and associates ), inferior conjunctivochalasis (grade 0–3 after Hirotani and associates ), superior or inferior lid wiper epitheliopathy (LWE; grade 0–3 after Yamamoto and associates ), eyelid shape (1 fold/2 folds in the eyelid), and eyelid ptosis (present/absent) ( Table 1 ).

Statistical Analyses

All data are presented as the means ± standard deviations. Statistical analyses were performed with the Student t tests, Pearson coefficient of correlation, and multiple linear regression analyses. A P value <.05 was considered statistically significant. All analyses were done with JMP for Windows, Version 7 (SAS Institute, Cary, North Carolina, USA).

Eyelid Pressure in Normal Eyes and Dry Eyes

The mean eyelid pressure for the normal eyes (N) group was 16.25 ± 6.18 mm Hg for the upper lid and 16.39 ± 6.82 mm Hg for the lower lid. For the dry eyes (D) group, the mean eyelid pressure was 20.23 ± 5.73 mm Hg for the upper lid and 19.55 ± 6.58 mm Hg for the lower lids. The values for both eyelids were significantly higher in the D group than in the N group ( Table 2 ; upper P < .0001, lower P = .0040). When the eyelid pressures were examined by age, no significant difference was observed between ages <39 years and and 40–49 years in the N and D groups. However, the eyelid pressures were significantly higher in the D group than the N group for the older ages, especially ages of 50–59 years ( Table 2 ; upper P = .0068, lower P = .0127) and 60–69 years ( Table 2 ; upper P = .0007, lower P = .0230). In the N group, all of the eyelid pressure values decreased with increasing age, while this trend was not observed in the D group, where the values for each age group were not significantly different, although no significant difference was observed between N and D groups in lower eyelid pressure for ages over 70 years ( Table 2 ).

Effect of Eyelid Pressure and Other Ocular Factors on Ocular Surface Staining Scores in Dry Eye Patients

The ocular surface staining scores in each region are shown in Table 3 . The correlations between the ocular surface staining scores and the eyelid pressure values of each region are shown in Table 4 . The ocular surface staining scores of the inferior cornea (KFS-I) and inferior conjunctiva (CFS-I) were significantly correlated with the higher pressures in the lower eyelid (r = 0.19 and r = 0.20, and P = .0307 and P =.0252, respectively). The correlations between the upper and lower eyelid pressure values and the staining scores for the superior and middle cornea and the intrapalpebral conjunctiva were not significant ( Table 4 ).

Table 4

Correlation Between Location of Ocular Surface Staining and All Evaluating Items in Dry Eye Patients

	KFS-S	KFS-M	KFS-I	CFS-S	CFS-T	CFS-N	CFS-I
Upper eyelid pressure
r	−0.14	−0.04	0.10	−0.07	0.11	0.17	0.06
P	.1260	.6288	.2805	.4537	.2338	.0647	.5380
Lower eyelid pressure
r	0.04	0.06	0.19	−0.05	0.10	0.13	0.20
P	.6774	.5333	.0307 a	.6151	.2858	.1459	.0252 a
Schirmer I test scores
r	−0.11	−0.14	−0.03	−0.10	−0.21	−0.25	−0.04
P	.2234	.1265	.7489	.2738	.0224 a	.0068 a	.6655
BUT
r	−0.22	−0.04	0.02	−0.27	−0.09	−0.02	−0.25
P	.0131 a	.6803	.8564	.0018 a	.3154	.8170	.0043 a
MGD
r	0.30	0.18	0.19	−0.11	0.21	0.20	0.19
P	.0012 a	.0507	.0435 a	.2387	.0251 a	.0263 a	.0371 a
TMH
r	0.13	−0.02	0.00	−0.06	−0.11	−0.05	−0.02
P	.1499	.8195	.9596	.5038	.2331	.6065	.7949
Superior conjuctivochalasis
r	0.12	0.00	−0.03	0.36	0.02	−0.01	0.03
P	.1954	.9764	.7448	<.0001 a	.8361	.9016	.7741
Inferior conjunctivochalasis
r	−0.06	−0.05	0.06	−0.01	0.04	0.03	0.03
P	.5237	.5843	.5152	.9316	.6218	.7712	.7371
Superior LWE
r	−0.01	−0.06	0.11	−0.17	0.06	0.18	0.02
P	.8880	.5277	.2054	.0507	.5098	.0475 a	.7935
Inferior LWE
r	−0.01	0.05	0.07	−0.18	0.09	0.09	0.02
P	.9045	.5925	.4335	.0435 a	.3076	.2954	.8360
Eyelid shape
r	−0.03	0.12	0.03	−0.08	0.04	0.10	−0.06
P	.7406	.1802	.7792	.3715	.6787	.2735	.5005
Eyelid ptosis
r	0.17	−0.07	−0.19	0.23	−0.14	−0.14	−0.10
P	.0632	.4406	.0429 a	.0122 a	.1420	.1441	.3040

Only gold members can continue reading. Log In or Register to continue

Share this:

• Click to share on Twitter (Opens in new window)
• Click to share on Facebook (Opens in new window)

Related

Related posts:

1. Confusing Eponyms
2. Toric Intraocular Lens Calculations Using Ratio of Anterior to Posterior Corneal Cylinder Power
3. Choroidal Thickness Changes After Photodynamic Therapy and Recurrence of Chronic Central Serous Chorioretinopathy
4. Reply

Stay updated, free articles. Join our Telegram channel

Join