Lipid tear deficiency in persistent dry eye after laser in situ keratomileusis and treatment results of new eye-warming device

The effect of incomplete blinking rate on corneal epithelial remodeling after trans-PRK surgery: a six-month study

Purpose

To evaluate the impact of incomplete blink rate on corneal epithelial thickness after transepithelial photorefractive keratectomy (Trans-PRK) surgery.

Methods

Trans-PRK patients were divided into two groups based on preoperative incomplete blinking rates, namely rates ≤0.5 (41 right eyes, group A) and rates >0.5 (65 right eyes, group B). We used anterior segment optical coherence tomography to measure the corneal epithelial thickness (CET) and lipiview to measure the number of blinks, incomplete blinking rate, and lipid layer thickness (LLT).

Results

In both groups, CET decreased at 1 week and 1 month, and the thicknesses in the IT, T, and ST regions exceeded the preoperative levels. Three months after Trans-PRK, the thickness exceeded the preoperative levels and continued to increase during subsequent follow-ups. The blinking times and LLT in both groups decreased at 1 week and gradually increased but did not return to preoperative levels. Group A maintained an incomplete blinking rate of over 0.5 at all postoperative periods. The incomplete blinking rate of group B remained above 0.5 postoperatively, although there was an improvement compared with preoperative rates. Both groups showed a correlation between changes in CET and incomplete blinking rate. There was a correlation between changes in LLT and the incomplete blinking rate after surgery.

Conclusion

Both groups showed uneven corneal epithelia thickening, which became more pronounced approaching the peripheral areas. In addition, changes in CET after surgery were positively correlated with the incomplete blinking rate in both patient groups. There was a negative correlation between postoperative LLT and incomplete blinking rate.

Advances in Sjögren's Syndrome Dry Eye Diagnostics: Biomarkers and Biomolecules beyond Clinical Symptoms

Sjögren's syndrome dry eye (SSDE) is a subset of Sjögren's syndrome marked by dry eye symptoms that is distinct from non-Sjögren's syndrome dry eye (NSSDE). As SSDE can lead to severe complications, its early detection is imperative. However, the differentiation between SSDE and NSSDE remains challenging due to overlapping clinical manifestations. This review endeavors to give a concise overview of the classification, pathophysiology, clinical features and presentation, ocular and systemic complications, clinical diagnosis, and management of SSDE. Despite advancements, limitations in current diagnostic methods underscore the need for novel diagnostic modalities. Thus, the current review examines various diagnostic biomarkers utilized for SSDE identification, encompassing serum, salivary, and tear analyses. Recent advancements in proteomic research and exosomal biomarkers offer promising diagnostic potential. Through a comprehensive literature review spanning from 2016 to 2023, we highlight molecular insights and advanced diagnostic modalities that have the potential to enhance our understanding and diagnosis of SSDE.

An Overview of the Dry Eye Disease in Sjögren's Syndrome Using Our Current Molecular Understanding

Sjögren's syndrome is a chronic and insidious auto-immune disease characterized by lymphocyte infiltration of exocrine glands. The patients typically present with ocular surface diseases related to dry eye and other systemic manifestations. However, due to the high prevalence of dry eye disease and the lack of objective and clinically reliable diagnostic tools, discriminating Sjögren's syndrome dry eye (SSDE) from non-Sjögren's syndrome dry eye (NSSDE) remains a challenge for clinicians. Diagnosing SS is important to improve the quality of life of patients through timely referral for systemic workups, as SS is associated with serious systemic complications such as lymphoma and other autoimmune diseases. The purpose of this article is to describe the current molecular understanding of Sjögren's syndrome and its implications for novel diagnostic modalities on the horizon. A literature review of the pre-clinical and clinical studies published between 2016 and 2022 was conducted. The SSDE pathophysiology and immunology pathways have become better understood in recent years. Novel diagnostic modalities, such as tear and saliva proteomics as well as exosomal biomarkers, provide hope on the horizon.

Post-LASIK dry eye disease: A comprehensive review of management and current treatment options

Laser-assisted in situ keratomileusis (LASIK) is a unique corneal stromal laser ablation method that uses an excimer laser to reach beneath corneal dome-shaped tissues. In contrast, surface ablation methods, such as photorefractive keratectomy, include removing epithelium and cutting off the Bowman's layer and the stromal tissue of the anterior corneal surface. Dry eye disease (DED) is the most common complication after LASIK. DED is a typical multi-factor disorder of the tear function and ocular surface that occurs when the eyes fail to produce efficient or adequate volumes of tears to moisturize the eyes. DED influences quality of life and visual perception, as symptoms often interfere with daily activities such as reading, writing, or using video display monitors. Generally, DED brings about discomfort, symptoms of visual disturbance, focal or global tear film instability with possible harm to the ocular surface, the increased osmolarity of the tear film, and subacute inflammation of the ocular surface. Almost all patients develop a degree of dryness in the postoperative period. Detection of preoperative DED and committed examination and treatment in the preoperative period, and continuing treatments postoperatively lead to rapid healing, fewer complications, and improved visual outcomes. To improve patient comfort and surgical outcomes, early treatment is required. Therefore, in this study, we aim to comprehensively review studies on the management and current treatment options for post-LASIK DED.

Management of Post-LASIK Dry Eye with Intense Pulsed Light in Combination with 0.1% Sodium Hyaluronate and Heated Eye Mask

INTRODUCTION

Laser in situ keratomelieusis (LASIK) is one of the most frequently performed refractive treatments. Dry eye (DE) is common in patients after LASIK and can be bothersome postoperatively. Therapies such as intense pulsed light (IPL), sodium hyaluronate (SH) and heated eye mask (HEM) have been reported to improve signs and symptoms of DE .

AIM

The purpose of this prospective study was to evaluate and compare the effects of IPL and 0.1% SH (IPL group, 50 eyes) and IPL in combination with 0.1% SH and HEM (IPL + group, 50 eyes) in participants with persistent post-LASIK DE.

METHODS

The final analysis included 100 patients (100 eyes) who had LASIK for myopic correction and had been experiencing moderate to severe DE following LASIK for over a year. Participants were randomly assigned to either the IPL group (2 IPL sessions) or IPL + group (2 IPL sessions and daily HEM for 4 weeks), and both groups continued the use of daily 0.1% SH (HYLO-COMOD®) preservative-free eye drops. Non-invasive tear break-up time (NITBUT), tear film lipid layer (TFLL), lower tear meniscus height (LTMH), meibomian gland quality (MGQ), meibomian gland expressibility (MGEx), corneal fluorescein staining (CFS), ocular surface disease index (OSDI) and artificial tear usage (ATU) survey were assessed at baseline (BL) and follow-up at 2 (F1) and 4 weeks (F2).

RESULTS

Following the treatment protocol, all dry eye (DE) parameters assessed in this study improved significantly (P < 0.05) in both groups at F2 compared with their respective BL measurements. Inter-group comparison at F2 found significant differences in their NITBUT (IPL: 6.06 ± 0.59 vs. IPL +: 6.67 ± 0.86, P < 0.001), TFLL (IPL: 1.90 ± 0.65 vs. IPL +: 1.60 ± 0.64, P = 0.021), LTMH (IPL: 0.186 ± 0.053 vs. 0.204 ± 0.034, P = 0.003), MGQ (IPL: 1.48 ± 0.54 vs. IPL +: 1.26 ± 0.56, P = 0.026), MGEx (IPL: 1.62 ± 0.53 vs. IPL +: 1.44 ± 0.50, P = 0.038) and OSDI (IPL: 32.54 ± 6.85 vs. IPL +: 29.76 ± 4.74, P = 0.001), while CFS score (IPL: 4.02 ± 0.65 vs. IPL +: 3.96 ± 0.73, P = 0.652) and ATU (IPL: 1.88 ± 0.63 vs. IPL +: 1.72 ± 0.50, P = 0.159) showed no significant difference.

CONCLUSION

Post-LASIK DE signs and symptoms can be improved by combining therapies such as IPL, HEM and 0.1% SH. Increased TFLL due to a combination of IPL, 0.1% SH and HEM had a greater positive impact on the subjective and objective DE measurements in participants with persistent post-LASIK DE.

A review of meibography for a refractive surgeon

Refractive surgery has evolved from being a therapeutic correction of high refractive errors to a cosmetic correction. The expectations associated with such a surgery are enormous and one has to anticipate all possible complications and side-effects that come with the procedure and prepare accordingly. The most common amongst these is post-refractive surgery dry eye of which Meibomian gland dysfunction is a commonly associated cause. We present an understanding of various diagnostic imaging modalities that can be used for evaluating meibomian glands which can also serve as a visual aid for patient understanding. We also describe various common conditions which can silently cause changes in the gland architecture and function which are to be considered and evaluated for.

Dry Eye After LASIK

Post-LASIK dry eye is the most common postoperative dry eye after ophthalmic surgeries. The clinical signs of post-LASIK dry eye include positive vital staining of the ocular surface, decreased tear breakup time and Schirmer test values, reduced corneal sensitivity, and decreased functional visual acuity. The symptoms and signs usually last for about 1 month after LASIK. A small number of patients continue to experience symptoms more than 1 year postoperatively. It has been suggested that the loss of corneal innervation caused by flap-making is the major cause, affecting the corneal-lacrimal gland, corneal-blinking, and blinking-meibomian gland reflexes, resulting in decreased aqueous and lipid tear secretion and mucin expression. A new type of corneal refractive surgery, SMILE, which has less impact on corneal nerves, induces less postoperative dry eye, supporting the association between corneal denervation and postoperative dry eye. As LASIK enhancement by flap-lifting induces fewer dry eye symptoms and signs than initial surgery, factors other than neurotrophic effects may be involved in the mechanisms of post-LASIK dry eye. Post-LASIK ocular surface pain is a type of postoperative chronic pain and discomfort, and is thought to be a different clinical entity from dry eye, possibly induced by abnormal reinnervation or neural sensitization of peripheral nerves and the central nervous system after LASIK. Treatments include tear supplements, anti-inflammatory agents, meibomian gland dysfunction management, ointment and eye patches, punctal plugs, and autologous serum eye drops. For patients with preoperative dry eye, careful patient selection, and preoperative ocular surface management are mandatory.

Dry Eye Post-Laser-Assisted In Situ Keratomileusis: Major Review and Latest Updates

Dry eye is one of the most common complications occurring after laser-assisted in situ keratomileusis (LASIK), with virtually all patients experiencing some degree of postoperative dry eye symptoms. Enhanced understanding of the pathophysiology and mechanism of dry eye development in addition to preoperative screening of patients who are prone to dry eye is essential for better patient satisfaction and for improving short-term visual outcome postoperatively. This article reviews the latest studies published on LASIK-associated dry eye, including epidemiology, pathophysiology, risk factors, preoperative assessment, and management.

Assessment of meibomian glands and tear film in post-refractive surgery patients

IMPORTANCE

Corneal refractive surgery may impact meibomian gland and tear film in post-refractive surgery patients.

BACKGROUND

To compare ocular surface parameters between post-refractive surgery patients and normal controls.

DESIGN

Cross-sectional single centre study.

PARTICIPANTS

A total of 120 eyes of 120 subjects were divided into three groups: (i) 60 controls and 60 patients underwent corneal refractive surgery at least 12 months ago; (ii) 30 post-laser in-situ keratomileusis (LASIK) patients and (iii) 30 post-laser epithelial keratomileusis (LASEK)/photo-refractive keratectomy (PRK) patients.

METHODS

Tear meniscus height, non-invasive keratographic tear film break-up time and meibography were measured using the Keratograph^® 5M. Fluorescein break-up time, ocular surface staining, examination of lid margins and meibomian glands, Schirmer's test and Ocular Surface Disease Index questionnaire were performed.

MAIN OUTCOME MEASURES

Ordinary logistic regression was performed to evaluate the impact of clinical variables including refractive surgery on the meiboscores.

RESULTS

In post-LASIK patients, ocular surface parameters including Ocular Surface Disease Index scores, fluorescein break-up time and staining scores, except Schirmer's scores, were significantly worse than those in controls (P < 0.050). Ocular surface staining scores in post-LASEK/PRK patients was higher than that in the controls (P = 0.001). In post-refractive surgery patients, grade of meibomian gland parameters and meiboscores were worse than those of controls (all P < 0.050). Histories of refractive surgery were associated with high meiboscore (β = 1.100, P = 0.043 for LASIK and β = 1.039, P = 0.042 for LASEK/PRK).

CONCLUSIONS AND RELEVANCE

Corneal refractive surgery may adversely affect the ocular surface, and a reduction of functional meibomian glands can contribute to chronic tear film dysfunction after corneal refractive surgery.

Influence of corneal cross-linking for keratoconus on several objective parameters of dry eye

PURPOSE

To evaluate the potential influence of corneal cross-linking (CXL) with ultraviolet-A light and riboflavin in keratoconic eyes on several objective parameters of dry eye syndrome.

METHODS

This prospective single center study included 30 consecutive eyes of 16 patients that underwent CXL with riboflavin and ultraviolet-A treatment (epithelial removal, 30 minutes soaking with riboflavin, 30 minutes of illumination with 365 nm, 3 mW/cm(2), 5 cm distance). Several dry eye syndrome parameters were evaluated preoperatively and 3 and 6 months after the procedure: intra-individual comparison of fluorescein and Rose bengal staining, height of tear film meniscus, and tear film break-up time.

RESULTS

Pathologic staining (more than 10 point-shaped areas or diffuse staining) with fluorescein was evident before CXL in 1 eye, 3 months after CXL in 1 eye, and 6 months after CXL in 1 eye. Rose bengal staining 3 and 6 months postoperatively was comparable to preoperative staining. Tear film height was reduced in 2 eyes before CXL and in 4 eyes 3 months postoperatively, and was normal in all eyes after 6 months. The number of eyes with reduced tear film break-up time was not significantly changed.

CONCLUSIONS

CXL had no significant impact on several parameters of dry eye syndrome 3 and 6 months postoperatively.

The role of corneal innervation in LASIK-induced neuropathic dry eye

Almost half the patients who undergo laser in situ keratomileusis (LASIK) experience dry eye following the procedure. However, the etiology of LASIK-induced dry eye is unclear. The purpose of this review is to examine and summarize the current evidence for the etiology of LASIK-induced dry eye, with a focus on ocular surface sensitivity and corneal innervation. Evidence suggests that the alteration of corneal nerves after LASIK is the most likely cause of the subjective symptoms of LASIK-induced dry eye, even though corneal sensitivity and the clinical indicators of dry eye return to apparently normal values within a year due to the partial recovery of the corneal nerve plexus. The hypothesis is explored that dry eye symptoms following LASIK may result from abnormal sensation due to LASIK-induced corneal neuropathy. Other factors, such as alterations in conjunctival goblet cell density, might also contribute to the symptoms and signs of LASIK-induced dry eye. Inter-relationships between nerve morphology, tear neuropeptide levels and dry eye require further investigation. A better understanding of this phenomenon may result in improved management of post-LASIK dry eye.

Evaluation of the ocular tolerance of a novel eyelid-warming device used for meibomian gland dysfunction

PURPOSE

Obstructive meibomian gland dysfunction (MGD) frequently induces a chronic complaint with various symptoms related to dry eye and discomfort. Previous research indicates a pivotal role for heat therapy for melting the meibum as part of any successful management plan, but delivery of constant temperature during treatment is vital. This study evaluated the performance of a novel device designed to deliver controlled, latent, moist heat to the eyelids and surrounding area.

METHODS

The signs, symptoms and ocular temperature of 25 normal subjects (M8, F17; age 29.2±5.7 years) were recorded before and after a 10min application of the Blephasteam(®) device. Ocular temperature (non-invasive ocular thermography; A40 Flir, UK), tear film stability (NIBUT), intra-ocular pressure (IOP), and ocular surface staining and hyperaemia were recorded. Results were checked for normality and compared using paired t-tests.

RESULTS

Temperatures in both eyelids were significantly greater after device application (upper +1.7±0.9°C; lower +2.1±0.7°C, p<0.0005). Bulbar conjunctival hyperaemia significantly decreased after treatment (p<0.005), but limbal and palpebral hyperaemia remained similar (p=0.33 and p=0.11, respectively). Ocular surface staining (p=0.74) and tear film stability (p=0.12) were unchanged in this normal cohort, and there was no significant change in IOP (13.8±2.0mmHg vs 12.9±2.2mmHg; p=0.092).

CONCLUSIONS

The Blephasteam(®) device provides effective levels of warming that would be sufficient to melt meibum, and no adverse ocular responses were recorded in this cohort, indicating that this is a safe device. Interestingly, even in this normal cohort, ocular surface redness appears less after treatment.

Nonobvious obstructive meibomian gland dysfunction

This review presents the rationale and supporting data for a recent paradigm shift in our understanding of meibomian gland dysfunction (MGD). The historical understanding of MGD has been that of an infectious hypersecretory disorder with obvious signs of inflammation, hypersecretion, and purulent excreta. The current understanding of MGD now includes the polar concept of a less obvious or nonobvious type of hyposecretory obstructive MGD, where inflammation and other signs of pathology may be absent unless special examination techniques are employed. A new term, nonobvious obstructive MGD (NOMGD), is used to describe what may be the most common form of obstructive MGD. Obstructive MGD is an area of growing importance because obstructive MGD is now recognized to be the most common cause of evaporative dry eye, and because NOMGD seems to be the precursor to obvious obstructive MGD, it is also an important area to understand. The prevalence of NOMGD seems to be very high but currently significantly underdiagnosed. This review presents the relevant anatomy and physiology, concepts of obstructive MGD, the usual absence of inflammation in obstructive MGD, nomenclature and classification of obstructive and NOMGD, clinical diagnosis of NOMGD emphasizing the necessity for diagnostic expression, the use of a new instrument for diagnostic expression providing a standardized method of assessing meibomian gland functionality, the complementary roles of the aqueous and lipid layers, and the specific treatment of NOMGD, emphasizing that the success of treatment of all forms of obstructive MGD is dependent on the relief of the obstruction.

Inner eyelid surface temperature as a function of warm compress methodology

PURPOSE

To (1) determine an optimal method of warm compress (WC) application to maximize heating meibomian glands in minimal time, (2) determine the maximum inner eyelid temperature achievable during 30 min of routine WC application, (3) examine the cooling curve for 10 min after WCs have been discontinued.

METHODS

Subjects were randomly assigned to one of three WC methodologies. Group A (GrA), (n = 10): 15 min WC application without reheating. GrB, (n = 10): 30 min WC application with reheating every 2 min. GrC, (n = 12): 30 min WC application optimizing contact with the lower lid and reheating every 2 min. WCs were heated to 45 +/- 0.5 degrees C. Outer and inner lower eyelid surface temperatures were measured at baseline and regular intervals.

RESULTS

GrA: the maximum outer and inner lower eyelid surface temperatures = 41.2 +/- 0.3 degrees C at 1 min and 38.8 +/- 0.2 degrees C after 4 min, respectively. GrB: the maximum outer upper eyelid temperature, 43.3 +/- 0.5 degrees C, was reached after 6 min while it required 30 min to reach the maximum inner lower eyelid temperature, 40.4 +/- 0.3 degrees C. GrC: it required 4 min to reach the maximum outer lower eyelid temperature, 42.2 +/- 0.4 degrees C, while it required 20 min to reach the maximum inner lower eyelid temperature, 40.8 +/- 0.3 degrees C.

CONCLUSIONS

To optimize WC efficiency, patients should (1) heat the WC to approximately 45 degrees C, (2) optimize contact between the WC and outer eyelid surfaces, (3) reheat the WC frequently and have a replacement heated WC on hand for exchange, and (4) perform the activity for at least 4 min in order to achieve an inner lower eyelid temperature > or = 40 degrees C. Longer therapy may be necessary for more severe obstructions. These data suggest that precise, customized, labor-intensive WC procedure is necessary to optimize treating meibomian gland dysfunction and obstruction using WCs.