Purpose
To evaluate dry eye and meibomian gland dysfunction after cataract surgery.
Design
Prospective observational case series.
Methods
We studied 58 eyes of 48 patients who underwent phacoemulsification and evaluated them preoperatively and at 1 month and 3 months postoperatively. Ocular symptom scores, lid margin abnormalities, superficial punctate keratopathies (SPKs), tear film break-up time (TBUT), Schirmer test, lower tear meniscus height, depth, and area using Fourier domain optical coherence tomography, meibum expressibility and images of the meibomian glands using meibography were measured.
Results
The ocular symptom scores were worse at 1 month and 3 months postoperatively ( P < 0.001 and P < 0.001, respectively). Lid margin abnormalities were significantly increased ( P < 0.001 and P < 0.001, respectively) and TBUT decreased postoperatively ( P < 0.001 and P < 0.001, respectively). Meibum expressibility decreased at 3 months postoperatively ( P = 0.016); however, meibography score, SPK, lower tear meniscus height, depth and area and the Schirmer test did not change significantly postoperatively (all P values >0.05).
Conclusion
Meibomian gland function may be altered without accompanying structural changes after cataract surgery.
Modern cataract surgery is one of the most successful surgical procedures performed today. In spite of excellent postoperative distance visual acuity obtained for most patients, some are distracted and dissatisfied because of tear film dysfunction, poor near vision or reduced contrast sensitivity. Tear film dysfunction due to the use of topical medications, reduced corneal sensitivity or conjunctival goblet cell loss have been most widely investigated. Changes in tear volume or production after surgery have been observed inconsistently. Some patients complain of ocular discomfort in spite of normal tear production and normal corneal surfaces.
Obstructive meibomian gland dysfunction (MGD) is the most common cause of evaporative dry-eye disease and is characterized by stagnation of meibomian gland lipids with or without qualitative or quantitative changes in meibum. Hyposecretion of lipids may result in tear film instability, ocular irritation and ultimately ocular surface disease. Multiple ocular and systemic factors, such as contact lens wear, giant papillary conjunctivitis, atopy, menopause, and psoriasis have been reported to cause MGD; however, the influence of cataract surgery on meibomian gland function has not been investigated.
Regarding blepharitis after ocular surgery, 1 study has been published. The authors reported that more than 30% of patients after post-laser in situ keratomileusis who complained of ocular symptoms had dry eye or blepharitis. However, they did not classify the blepharitis as anterior or posterior (MGD) blepharitis, and changes in ocular parameters related to blepharitis were not discussed. The purpose of this study was to evaluate whether cataract surgery affects meibomian gland function and to investigate potential associated changes in ocular surface parameters.
Patients and Methods
This study was performed in accordance with the tenets of the World Medical Association of Helsinki. The prospective study protocol was approved by the Severance Hospital Institutional Review Board, Seoul, South Korea, and registered at http://www.clinicaltrials.gov (identification no. NCT01942642 ). Informed consent was obtained from all subjects after explanation of the purpose and possible consequences of the study.
We evaluated 55 patients (66 eyes) for inclusion in this study. Of them 7 patients (8 eyes) were lost to follow-up. The remaining 48 patients (58 eyes) are the subject of this report. The mean age of the 48 patients was 68.3 ± 11.7 years, and 27 were female.
Eyes were categorized according to whether they had anterior or posterior blepharitis. Anterior blepharitis was further categorized as staphylococcal or seborrheic, and posterior blepharitis was further characterized as seborrheic or obstructive. Anterior staphylococcal blepharitis was diagnosed by the presence of eyelid crusting and collarettes. Anterior seborrheic blepharitis was diagnosed by the presence of greasy scales on lid margins and around the eyelashes. Seborrheic posterior blepharitis (MGD) was diagnosed by excessive, thickened meibum secretion with expression. Obstructive MGD was diagnosed when there was plugging of the meibomian gland orifices and hyposecretion of meibum with expression. None of the patients had had staphylococcal or seborrheic anterior blepharitis or seborrheic MGD preoperatively.
Patients who had other comorbid ocular diseases, such as ocular allergies, continuous use of topical ocular medications before surgery, or histories of ocular surgery or ocular injury, were excluded. Patients who already had severe obstructive MGD before surgery, abnormal findings on the lid margin (>3 positive findings), reduced meibum expression (>grade 2), or obstructed gland dropout (meibography score >3) were also excluded.
Of the patients, the 10 who received cataract surgery in both eyes had a period of at least 2 weeks between surgical procedures.
Cataract Surgery
All cataract surgery was performed by phacoemulsification through a 3.2 mm clear corneal temporal incision under topical anesthesia by one of the authors (KYS). The intraocular lens implant was either the Tecnis 1-piece ZCB00 (Abbott Medical Optics, Santa Ana, California), or the Acrysof IQ SN60WF (Alcon Laboratories, Fort Worth, Texas). At the end of surgery, the corneal incision was sealed with stromal hydration. There were no intraoperative or postoperative complications. Postoperatively, topical levofloxacin 0.5% (Cravit; Santen Pharmaceutical, Osaka, Japan) and prednisolone acetate 1% (PredForte, Allergan, Irvine, California) were instilled 4 times daily for 4 weeks.
Patients were instructed to wash their faces as usual after 1 week postoperatively and to avoid pressing on the operated eyes for 1 month postoperatively. No special instructions for lid massage or lid hygiene were given.
Clinical Examinations
Ocular symptoms, including ocular fatigue, discharge, foreign-body sensation, dryness, uncomfortable sensation, sticky sensation, pain, epiphora, itching, redness, heavy sensation, glare, excessive blinking, and history of chalazion or hordeolum, were evaluated by a questionnaire. The total scores of symptoms ranged from 0 to 14, with higher scores representing greater severity.
Lid margin abnormalities were scored as 0 (absent) or 1 (present) for the following 4 parameters: vascular engorgement, plugged meibomian gland orifices, anterior or posterior displacement of the mucocutaneous junction, and irregularity of lid margin. The sum was recorded as 0 through 4.
Tear film break-up time (TBUT) was evaluated by placing a single fluorescein strip over the inferior tear meniscus after instilling a drop of normal saline. Time from the last blink to the first appearance of a randomly distributed dry spot on the cornea was recorded in seconds. The mean time for 3 attempts was recorded. After measuring TBUT, SPK was graded as 0 (no staining); 1 (less than one third of the corneal surface); 2 (between one third and half of the corneal surface); or 3 (half or more of the corneal surface).
Lower tear meniscus status was evaluated using Fourier domain optical coherence tomography (OCT) (RTVue; Optovue, Fremont, California). Vertical 2 mm scan images at the middle of the lower eyelid were obtained 3 times per eye. The patients were asked to refrain from blinking during the scanning. The tear meniscus height, depth and area were measured using virtual calipers provided by Fourier domain OCT software. Tear meniscus height was defined as the distance between the upper meniscus on the cornea and the lower meniscus on the lid. The tear meniscus depth was defined as the distance from the midpoint of the air/meniscus interface to the cornea/lower eyelid junction, and the tear meniscus area was defined as the area consisting of the boundaries of the cornea, the lower eyelid and the tear meniscus.
Expressibility of the meibum was scored by the application of digital pressure to the central third of the upper tarsus. The ease of meibum secretion was graded as follows: 0 (clear meibum easily expressed); 1 (cloudy meibum expressed with mild pressure); 2 (cloudy meibum expressed with more than moderate pressure); and 3 (meibum not expressed, even with heavy pressure) ; higher scores represented a more obstructive status.
The morphology of meibomian glands was evaluated by meibography (BG-4M; Topcon, Tokyo, Japan) using a noncontact recording system that consists of an infrared transmitting filter (IR-83; Hoya, Tokyo, Japan) and an infrared charge-coupled video camera (XC-EI50; Sony, Tokyo, Japan). The upper and lower eyelids were everted and images were obtained. Meibography scores, which quantitate obstruction of the meibomian glands, were obtained using the following grades for each eyelid: 0 (no loss of meibomian glands); 1 (meibomian gland loss involving less than one third of the total meibomian gland area); 2 (area lost between one third and two thirds of the total meibomian gland area); and 3 (area lost more than two thirds of the total meibomian gland area). The total meibography score was the sum of the scores of the upper and lower lids and was recorded as 0 to 6.
The Schirmer test was performed without topical anesthesia as the final step in the examination by placing a standard paper strip in the mid-lateral portion of the lower fornix. The amount of wetting was recorded after 5 minutes. Patients were asked to blink normally during the test.
All measurements were performed by one of the authors (KYS) preoperatively, at 1 month postoperatively, and at 3 months postoperatively. Unoperated fellow eyes were not examined for the study.
Statistics
Normal distribution of the data was verified using the Kolmogorov-Smirnov test. A linear mixed model with Bonferroni post hoc analysis was used to evaluate repeated measurements of continuous values, such as ocular symptom score, TBUT, SPK, Schirmer test, and tear meniscus height, depth and area. A generalized linear mixed model analysis was used for repeated measurements of noncontinuous values, including lid margin abnormality, each parameter of lid margin abnormality, meibum expressibility, and meibography score. Statistical analyses were performed using SPSS for Windows (v 20.0, SPSS, Chicago, Illinois). P values less than 0.05 were considered significant.
Results
Ocular symptom scores were significantly worse postoperatively than they were preoperatively (1.5 ± 1.1 preoperatively, 3.6 ± 1.1 at 1 month postoperatively and 3.9 ± 1.7 at 3 months postoperatively; P < 0.001 and P < 0.001, respectively) ( Table ). Lid margin abnormalities were significantly increased at 1 month and 3 months postoperatively ( P < 0.001 and P < 0.001, respectively) ( Table ). Vascular engorgement was observed in 23 eyes (39.7 %) preoperatively, 42 eyes (72.4 %) at 1 month postoperatively, and 41 eyes (70.7 %) at 3 months postoperatively ( P < 0.001 and P < 0.001, respectively) ( Figure 1 ). Plugging of meibomian gland orifices was observed in 30 eyes (51.7 %) preoperatively, 43 eyes (74.1 %) at 1 month postoperatively, and 49 eyes (84.5 %) at 3 months postoperatively ( P = 0.007 and P < 0.001, respectively) ( Figure 1 and Figure 2 , left and right). The mucocutaneous junction was displaced in 16 eyes (27.6 %) preoperatively, in 18 eyes (31.0 %) at 1 month postoperatively, and in 20 eyes (34.5 %) at 3 months postoperatively ( P = 0.488, P = 0.285, respectively) ( Figure 1 and Figure 3 , left and right). Lid margin irregularity was noted in 16 eyes (27.6 %) preoperatively and in 20 eyes (34.5 %) at 1 month and 3 months postoperatively ( P = 0.303, P = 0.491, respectively) ( Figure 1 ).
| Parameters | Baseline | 1 month | 3 months | P Value | ||
|---|---|---|---|---|---|---|
| Overall | Baseline vs 1 month | Baseline vs 3 months | ||||
| Ocular symptom score a | 1.5 ± 1.1 | 3.6 ± 1.1 | 3.9 ± 1.7 | <0.001 | <0.001 | <0.001 |
| Lid margin abnormality b | 1.5 ± 1.1 | 2.1 ± 1.1 | 2.3 ± 0.9 | <0.001 | <0.001 | <0.001 |
| Meibum expressibility b | 1.7 ± 0.8 | 1.8 ± 0.8 | 2.1 ± 0.7 | 0.009 | 0.490 | 0.016 |
| Meibography score b | ||||||
| Upper lid | 0.5 ± 0.8 | 0.5 ± 1.0 | 0.6 ± 1.0 | 0.714 | >0.999 | >0.999 |
| Lower lid | 1.1 ± 0.8 | 1.2 ± 1.0 | 1.2 ± 1.1 | 0.220 | 0.264 | 0.689 |
| Total | 1.5 ± 1.5 | 1.7 ± 1.8 | 1.7 ± 1.8 | 0.229 | 0.262 | 0.432 |
| TBUT (sec) a | 6.7 ± 3.0 | 4.2 ± 1.9 | 4.1 ± 2.0 | <0.001 | <0.001 | <0.001 |
| SPK b | 0.4 ± 0.8 | 0.4 ± 0.7 | 0.5 ± 0.9 | 0.558 | 0.924 | 0.924 |
| Schirmer test (mm) a | 10.0 ± 3.8 | 10.9 ± 7.0 | 11.0 ± 6.7 | 0.672 | >0.999 | >0.999 |
| Lower tear meniscus assessment by FD-OCT a | ||||||
| Height (μm) | 261.2 ± 77.43 | 267.2 ± 75.96 | 268.3 ± 68.84 | 0.892 | >0.999 | >0.999 |
| Depth (μm) | 186.1 ± 50.78 | 183.0 ± 64.80 | 200.0 ± 69.16 | 0.529 | >0.999 | >0.999 |
| Area (10 −9 mm 2 ) | 25.8 ± 13.2 | 26.2 ± 15.2 | 29.2 ± 17.0 | 0.638 | >0.999 | >0.999 |
a Continuous values were analyzed by linear mixed model with Bonferroni post hoc analysis.
b Noncontinuous values were analyzed by generalized linear mixed model analysis with Bonferroni post hoc analysis.
