Ocular Surface Changes in Laser in situ Keratomileusis-induced Neurotrophic Epitheliopathy

Efficacy of topical 0.05% cyclosporine A and 0.1% sodium hyaluronate in post-refractive surgery chronic dry eye patients with ocular pain

BACKGROUND

The management of post-refractive surgery dry eye disease (DED) can be challenging in clinical practice, and patients usually show an incomplete response to traditional artificial tears, especially when it is complicated with ocular pain. Therefore, we aim to investigate the efficacy of combined topical 0.05% cyclosporine A and 0.1% sodium hyaluronate treatment in post-refractive surgery DED patients with ocular pain unresponsive to traditional artificial tears.

METHODS

We enrolled 30 patients with post-refractive surgery DED with ocular pain who were unresponsive to traditional artificial tears. Topical 0.05% cyclosporine A and 0.1% sodium hyaluronate were used for 3 months. They were evaluated at baseline and 1 and 3 months for dry eye and ocular pain symptoms and objective parameters, including Numerical Rating Scale (NRS), Neuropathic Pain Symptom Inventory modified for the Eye (NPSI-Eye), tear break-up time (TBUT), Schirmer I test (SIt), corneal fluorescein staining (CFS), corneal sensitivity, and corneal nerve morphology. In addition, tear levels of inflammatory cytokines and neuropeptides were measured using the Luminex assay.

RESULTS

After 3 months of treatment, patients showed a statistically significant improvement in the ocular surface disease index (OSDI), TBUT, SIt, CFS, and corneal sensitivity (all P < 0.01) using linear mixed models. As for ocular pain parameters, the NRS and NPSI-Eye scores were significantly reduced (both P < 0.05) and positively correlated with the OSDI and CFS scores. Additionally, tear IL-1β, IL-6, and TNF-α levels were improved better than pre-treatment (P = 0.01, 0.03, 0.02, respectively).

CONCLUSION

In patients with post-refractive surgery DED with ocular pain, combined topical 0.05% cyclosporine A and 0.1% sodium hyaluronate treatment improved tear film stability, dry eye discomfort, and ocular pain, effectively controlling ocular inflammation.

TRIAL REGISTRATION

Registration number: NCT06043908.

Changes of dry eye parameters after small incision lenticule extraction surgery in patients with different ocular surface disease index scores

To evaluate the changes of dry eye parameters after small incision lenticule extraction (SMILE) surgery in patients with different ocular surface disease index (OSDI) scores. Prospective research. Participants were divided into two groups: Group A, OSDI < 13; and Group B, OSDI ≥ 13. The OSDI scores, tear meniscus height (TMH), first non-invasive tear film break-up time (NIBUT-First), and meibomian gland loss (MGL, %) were recorded at postoperative 1 -week and 1-month.113 eyes (57 patients) were enrolled, 70 eyes in Group A, and 43 eyes in Group B. In Group A, the OSDI scores significantly increased at 1-week and 1-month postoperative (all P < 0.001); the TMH, NIBUT-First and lipid layer grade significantly decreased at postoperative 1-week (P = 0.003, 0.005, 0.007, 0.004, respectively), but returned to preoperative level at 1-month postoperative. In Group B, only the lipid layer grade significantly decreased at postoperative 1-week (P < 0.05). Patients with different preoperative OSDI scores may experience different changes early after SMILE surgery. Patients with OSDI scores < 13 may experience more dramatic changes in dry eye symptoms which would resolve, while subjective complains could still exists at 1 month after surgery.

Patient-Reported Dry Eye Outcomes After Myopic Femtosecond-LASIK: A 6-Month Prospective Analysis

Purpose

To evaluate patient-reported outcomes in relation to dry eye symptoms following femtosecond LASIK (FS-LASIK).

Methods

This study was conducted as a prospective, observational case series of patients undergoing bilateral myopic FS-LASIK at a single private practice institution. Enrolled patients were prospectively administered a standardized Dry Eye Symptom Index survey (analog score of 1 to 5 with 5 being the worst) prior to treatment and at 6-months after FS-LASIK. The following objective measurements were also recorded: objective scatter index (OSI), tear film osmolarity (TFO), and automated tear break-up times (TBUT).

Results

There were 40 enrolled patients who underwent bilateral myopic FS-LASIK and completed the 6-month study period. The Dry Eye Symptom Index score improved from 2.3 (2.0-2.6, 95% Confidence Intervals) prior to treatment to 1.3 (1.0-1.5) at 6 months (p < 0.0001). Subset analysis of the subjective dry eye symptoms showed improvement in "grittiness" (p = 0.001) but not in "light sensitivity" or "soreness" (p = 0.13 and p = 0.24, respectively). There were no significant changes in the OSI, TFO, or TBUT measurements at 6 months (p > 0.05 for all), and there were no adverse events or complications during the study period.

Conclusion

Patient-reported dry eye symptoms improve after 6 months following myopic FS-LASIK. This did not correlate with the objective dry eye measurement changes at 6 months.

Ferroptosis in the Lacrimal Gland Is Involved in Dry Eye Syndrome Induced by Corneal Nerve Severing

Purpose

Dry eye syndrome (DES) is a prevalent postoperative complication after myopic corneal refractive surgeries and the main cause of postoperative dissatisfaction. Although great efforts have been made in recent decades, the molecular mechanism of postoperative DES remains poorly understood. Here, we used a series of bioinformatics approaches and experimental methods to investigate the potential mechanism involved in postoperative DES.

Methods

BALB/c mice were randomly divided into sham, unilateral corneal nerve cutting (UCNV) + saline, UCNV + vasoactive intestinal peptide (VIP), and UCNV + ferrostatin-1 (Fer-1, inhibitor of ferroptosis) groups. Corneal lissamine green dye and tear volume were measured before and two weeks after the surgery in all groups. Lacrimal glands were collected for secretory function testing, RNA sequencing, ferroptosis verification, and inflammatory factor detection.

Results

UCNV significantly induced bilateral decreases in tear secretion. Inhibition of the maturation and release of secretory vesicles was observed in bilateral lacrimal glands. More importantly, UCNV induced ferroptosis in bilateral lacrimal glands. Furthermore, UCNV significantly decreased VIP, a neural transmitter, in bilateral lacrimal glands, which increased Hif1a, the dominant transcription factor of transferrin receptor protein 1 (TfR1). Supplementary VIP inhibited ferroptosis, which decreased the inflammatory reaction and promoted the maturation and release of secretory vesicles. Supplementary VIP and Fer-1 improved tear secretion.

Conclusions

Our data suggest a novel mechanism by which UCNV induces bilateral ferroptosis through the VIP/Hif1a/TfR1 pathway, which might be a promising therapeutic target for DES-induced by corneal refractive surgeries.

The structural and functional corneal reinnervation mechanism at different regions after LASIK-an in vivo confocal microscopy study

PURPOSE

To determine the recovery of structural and functional corneal sensory nerves within the LASIK flap in order to provide insight to more proximal corneal reinnervation and symptoms post-LASIK.

METHODS

Twenty participants underwent femtosecond LASIK with a superior flap hinge. Ocular Comfort Index in Chinese (OCI-C), Cochet-Bonnet esthesiometry, and in vivo confocal microscopy were conducted before surgery and 1 week, 1-, 3-, and 6-months post-LASIK to measure symptoms, corneal sensitivity, nerve fiber density, width, and the number of interconnections within the flap (central and mid-temporal regions), and next to the superior flap hinge. Linear mixed models were used to compare differences between corneal regions at each time point post-LASIK and changes over time post-LASIK. Spearman's correlation tests were used to examine the associations between variables post-LASIK.

RESULTS

The least reduction in sensitivity (P < 0.03) and in nerve fiber density (P < 0.02) was found near the flap hinge compared to other regions, but no regional differences were found in nerve fiber width and interconnections. Nerve fiber density and the number of interconnections at all regions within the flap recovered over time (P < 0.02). The recovery of corneal sensitivity and nerve fiber width was only seen at the central and temporal regions (P < 0.04). No association was found between sensitivity and nerve parameters, but a higher OCI-C score was associated with a lower nerve fiber density near the hinge (r =  - 0.43, P = 0.003) over time post-LASIK.

CONCLUSION

Corneal sensitivity and density are preserved in the hinge, but this preservation of the corneal nerve damage does not affect the nerve morphology.

Advantages of Small Incision Lenticule Extraction (SMILE) for Mass Eye and Ear Special Issue

This review summarizes the advantages of Small-incision lenticule extraction (SMILE), including improved patient intraoperative experience, improved postoperative ocular surface, low incidence of regression, low re-treatment rates, and advantageous biomechanical corneal stability. Visual and refractive outcomes are similar to those achieved with LASIK, notably in large population studies. Since the inception of SMILE almost 10 years ago, the procedure has been rapidly growing in popularity. With the implementation of the novel SMILE technology in their practice, refractive surgeons generate excitement and potential for expanding the refractive market. Other parts of the world, including Asia, Europe, and Russia, SMILE has become the most popular refractive procedure performed. It is speculated that as SMILE continues to grow in popularity in the US since FDA approval in 2016 and more refractive surgeons implement this technology into their practice, it will drive an increase in the refractive market similar to what is seen in other countries.

Plasmacytoid dendritic cells in the eye

Plasmacytoid dendritic cells (pDCs) are a unique subpopulation of immune cells, distinct from classical dendritic cells. pDCs are generated in the bone marrow and following development, they typically home to secondary lymphoid tissues. While peripheral tissues are generally devoid of pDCs during steady state, few tissues, including the lung, kidney, vagina, and in particular ocular tissues harbor resident pDCs. pDCs were originally appreciated for their potential to produce large quantities of type I interferons in viral immunity. Subsequent studies have now unraveled their pivotal role in mediating immune responses, in particular in the induction of tolerance. In this review, we summarize our current knowledge on pDCs in ocular tissues in both mice and humans, in particular in the cornea, limbus, conjunctiva, choroid, retina, and lacrimal gland. Further, we will review our current understanding on the significance of pDCs in ameliorating inflammatory responses during herpes simplex virus keratitis, sterile inflammation, and corneal transplantation. Moreover, we describe their novel and pivotal neuroprotective role, their key function in preserving corneal angiogenic privilege, as well as their potential application as a cell-based therapy for ocular diseases.

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.

Influence of Incision Size on Dry Eye Symptoms in the Small Incision Lenticule Extraction Procedure

PURPOSE

To evaluate the influence of incision size on dry eye symptoms in the small incision lenticule extraction (SMILE) procedure.

METHODS

Ninety-four eyes of 47 patients with myopia and/or myopic astigmatism who had undergone the SMILE procedure were enrolled in this study. The patients were divided into 3 groups according to the incision size (2, 3, and 4 mm) applied during the SMILE procedure.

RESULTS

There were no significant differences among the groups in respect to age and sex (P values 0.251 and 0.974, respectively) and in respect to preoperative, postoperative first day, first week, first month, third month, and sixth month values of the Ocular Surface Disease Index score, tear break-up time, ST1, and staining grades.

CONCLUSIONS

There was no difference in dry eye symptoms with 2-, 3-, and 4-mm incisions. In the learning period of SMILE surgery, larger incision sites can be used to make the procedure easier.

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.

Long-term Effects of LASIK on Corneal Innervation and Tear Neuropeptides and the Associations With Dry Eye

PURPOSE

To investigate the associations between dry eye, corneal nerves, and tear neuroptides in dry eye after LASIK.

METHODS

A single visit cross-sectional study was performed. Twenty participants who had LASIK more than 12 months prior and 20 healthy participants were recruited. Ocular comfort, tear functions, ocular surface sensitivity, basal tear collection, and corneal nerve morphology assessments were conducted. Tear substance P and calcitonin gene-related peptide (CGRP) concentrations were determined using ELISAs. Differences in variables between groups were examined using an independent t test or Mann-Whitney U test, as appropriate. Associations between variables in the post-LASIK group were examined using a Spearman's correlation test. A P value of less than .05 was considered significant.

RESULTS

Central corneal nerve morphology parameters were all altered in the post-LASIK group (P < .05). Higher ocular discomfort (P = .01), tear CGRP concentration (P = .001), and conjunctival sensitivity (P < .009) were found in the post-LASIK group. There was a positive association between dry eye symptoms and superior corneal sensitivity (P = .51, P = .02) and tear substance P concentration (P = .52, P < .03).

CONCLUSIONS

This study provides evidence of the association between tear neuropeptides, conjunctival sensitivity, and symptoms in symptomatic patients after LASIK. The differences in nerve morphology, neuropeptide, and ocular surface sensitivity between symptomatic and asymptomatic patients after LASIK are required to better understand the mechanism of dry eye after LASIK. [J Refract Surg. 2016;32(8):518-524.].

Recent advances in laser in situ keratomileusis-associated dry eye

Dry eye is the most common complication after laser in situ keratomileusis (LASIK). The major cause of LASIK-associated dry eye is corneal nerve damage. Early identification and treatment of post-operative dry eye are essential to prevent further ocular surface damage. This article reviews the recent studies of LASIK-associated dry eye, including clinical features, aetiology, risk factors, evaluations and treatment. The applications of novel technologies in LASIK-associated dry eye evaluation like anterior segment spectral-domain optical coherence tomography (SD-OCT) and corneal confocal microscopy are also introduced in this review.

Small incision lenticule extraction (SMILE) history, fundamentals of a new refractive surgery technique and clinical outcomes

This review summarizes the current status of the small incision lenticule extraction (SMILE) procedure. Following the early work by Sekundo et al. and Shah et al., SMILE has become increasingly popular. The accuracy of the creation of the lenticule with the VisuMax femtosecond laser (Carl Zeiss Meditec) has been verified using very high-frequency (VHF) digital ultrasound and optical coherence tomography (OCT). Visual and refractive outcomes have been shown to be similar to those achieved with laser in situ keratomileusis (LASIK), notably in a large population reported by Hjortdal, Vestergaard et al. Safety in terms of the change in corrected distance visual acuity (CDVA) has also been shown to be similar to LASIK. It was expected that there would be less postoperative dry eye after SMILE compared to LASIK because the anterior stroma is disturbed only by the small incision, meaning that the anterior corneal nerves should be less affected. A number of studies have demonstrated a lower reduction and faster recovery of corneal sensation after SMILE than LASIK. Some studies have also used confocal microscopy to demonstrate a lower decrease in subbasal nerve fiber density after SMILE than LASIK. The potential biomechanical advantages of SMILE have been modeled by Reinstein et al. based on the non-linearity of tensile strength through the stroma. Studies have reported a similar change in Ocular Response Analyzer (Reichert) parameters after SMILE and LASIK, however, these have previously been shown to be unreliable as a representation of corneal biomechanics. Retreatment options after SMILE are discussed. Tissue addition applications of the SMILE procedure are also discussed including the potential for cryo-preservation of the lenticule for later reimplantation (Mohamed-Noriega, Angunawela, Lim et al.), and a new procedure referred to as endokeratophakia in which a myopic SMILE lenticule is implanted into a hyperopic patient (Pradhan et al.). Finally, studies reporting microdistortions in Bowman's layer and corneal wound healing responses are also described.

Post-LASIK dry eye

Laser-assisted in situ keratomileusis (LASIK) is a frequently performed corneal refractive surgery with excellent refractive outcomes. The most common complication of LASIK is dry eyes, with virtually all patients developing some degree of dryness in the immediate postoperative period. Identifying preoperative dry eyes, and conscientious attention and treatment in the perioperative time period, can lead to enhanced patient satisfaction and more accurate visual outcomes. Improved understanding of the development of dry eyes after LASIK will advance our understanding of the complex pathophysiology of dry eye disease.

Efficacy of punctal occlusion in management of dry eyes after laser in situ keratomileusis for myopia

PURPOSE

To evaluate the effect of punctal plug use in preventing dry eye after laser in situ keratomileusis (LASIK).

MATERIALS AND METHODS

A randomized clinical trial at a tertiary eye care center, Riyadh, Saudi Arabia. Participants underwent LASIK for myopia in both eyes and a lower punctal occlusion in one eye only while the other eye served as control. Both eyes received the same postoperative medications except for lubricant duration (subject eye: four times per day for one week; control eye: four times per day for 6 months). Participants were evaluated at 1 week, 2, and 6 months after surgery for signs and symptoms of dry eye. The main outcome measures were visual acuity; ocular surface parameters; and Ocular Surface Disease Index questionnaire.

RESULTS

Seventy-eight eyes of 39 patients were included in this study. The Ocular Surface Disease Index scores of eyes with punctal plugs were better at all follow-up visits, and the differences between both eyes were statistically significant (1 week, p < 0.0001; 2 months, p < 0.0001; 6 months, p = 0.008). At the final follow-up visit, the percentage of normal eyes was higher in eyes with punctal plugs for all ocular surface parameters (Schirmer 1 test, 94.9%; tear breakup time, 77.8%; punctate epithelial keratitis score, 71.8%) compared to eyes without occlusion (Schirmer 1 test, 92.3%; tear breakup time, 58.3%; punctate epithelial keratitis score, 53.8%); however, such differences were not statistically significant.

CONCLUSION

Punctal plug insertion after LASIK surgeries may minimize the need for frequent lubricant application and hence improve patient satisfaction.

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.

MMP-9 and the perioperative management of LASIK surgery

PURPOSE OF REVIEW

Hyperosmolarity is a central mechanism causing ocular surface inflammation and eye irritation in typical patients suffering from tear dysfunction. Tear composition in dry eyes, or dysfunctional tear syndrome, may destabilize the tear film and cause ocular surface epithelial disease. Increased activity of matrix metalloproteinases (MMPs), especially MMP-9, plays a critical role in wound healing and inflammation and is primarily responsible for the pathologic alterations to the ocular surface that leads to a dysfunctional tear state.

RECENT FINDINGS

Altered corneal epithelial barrier function is the cause for ocular irritation and visual morbidity in dry eye disease. The increased MMP-9 activity in dry eyes may contribute to deranged corneal epithelial barrier function, increased corneal epithelial desquamation, and corneal surface irregularity.

SUMMARY

Dry eye is one of the most common complications of photorefractive keratectomy and laser in-situ keratomileusis (LASIK). LASIK has both a neurotrophic effect on the cornea and leads to a physical change in corneal shape that results in a change in tear dynamics, leading to ocular surface desiccation. The reduction in tear function after LASIK may induce an increase in osmolarity and consequently raise the concentration of proinflammatory cytokines and MMP-9 in the tear film, which results in dry eyes and insufficient attachment between the corneal flap and the corneal bed. Appropriate diagnosis and management of dysfunctional tear syndrome may lead to less postoperative LASIK complications.

Upper and lower tear menisci after laser in situ keratomileusis

OBJECTIVES

To determine upper and lower tear menisci using optical coherence tomography (OCT) in volunteers after laser in situ keratomileusis (LASIK) for myopia.

METHODS

Thirty-five eyes of 35 nonsurgical volunteers were evaluated. Twenty-eight eyes of 28 volunteers who underwent LASIK served as the study group. The height, area, and volume of the upper and lower tear menisci were obtained in the study group, using OCT before surgery, 1 week, 1 month, and 20 months after surgery. At each visit, Schirmer test (type I, without anesthesia), tear break-up time, and corneal fluorescein staining score were evaluated. OCT imaging was conducted in the nonsurgical group with the same settings.

RESULTS

The lower tear meniscus volume at baseline were significantly smaller in the study group compared with the nonsurgical group (t test, P < 0.01). The upper tear meniscus volume decreased from 0.44 +/- 0.11 microL to 0.37 +/- 0.08 microL at 1 month after surgery (P < 0.05). The lower tear meniscus volume (0.54 +/- 0.15 microL) reduced to 0.44 +/- 0.10 microL at 1 month after surgery (posthoc, P < 0.05). For the subgroup analysis, tear menisci, Schirmer test, and tear break-up time after LASIK decreased during the first 1 month (P < 0.05) and recovered by 20 months after surgery (t test, P > 0.05).

CONCLUSIONS

The upper and lower tear menisci decreased up to 1 month after LASIK and recovered by 20 months. OCT is a useful tool for evaluating the tear system in a noninvasive manner.

Eye Dryness Sensations After Refractive Surgery: Impaired Tear Secretion or "Phantom" Cornea?

The cornea is richly innervated by various functional types of sensory nerve fibers. When stimulated, these fibers evoke conscious sensations of different quality including ocular dryness, discomfort, and pain. Refractive surgery involves a variable degree of damage to corneal nerves. This leads to an altered expression of membrane ion channels at the injured and regenerating nerve fibers, giving rise to aberrant spontaneous and stimulus-evoked nerve impulse firing. It is speculated that these abnormal sensory discharges are read by the brain as ocular surface dryness. This would explain the high incidence of eye dryness sensations after photorefractive surgery, which are experienced by a large number of patients despite the often modest disturbance of tear secretion. Therefore, drugs that reduce abnormal activity in injured nerves may represent a therapeutic alternative for eye dryness sensations after refractive surgery.

Neurotrophic Mediators and Corneal Wound Healing

Neurotrophic keratopathy is an ocular pathological condition that remains difficult to treat. The loss of trigeminal nerve function and corneal sensation that underlies this condition can lead to the development of various disorders of the cornea. Substance P, a sensory neurotransmitter produced by the trigeminal nerve, has been investigated for its effect on corneal epithelial wound healing. Substance P by itself has no direct effect on corneal epithelial migration, but it manifests a synergistic action with insulin-like growth factor-1 (IGF-1) in both epithelial migration in vitro and corneal wound healing in vivo. The minimal amino acid sequences of both substance P and IGF-1 that are required for such effects have been determined. With use of these minimal amino acid sequences, the potential adverse consequences of treatment with the full-length polypeptides may be avoided. The application of eye drops containing a substance P-derived peptide and IGF-1 has proved clinically effective for the treatment of patients with persistent epithelial defects of the cornea.

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

PURPOSE

To determine whether lipid tear deficiency is a significant pathogenic factor in persistent dry eyes after laser in situ keratomileusis (LASIK).

SETTING

Ocular Surface Center, Miami, Florida, USA.

METHODS

Thirty-four eyes of 17 patients (mean 46.35 years +/- 11 [SD]) complaining of persistent dryness more than 12 months after LASIK were prospectively studied by symptom scoring and kinetic analysis of tear interference image, tear breakup time, and fluorescein clearance test. Once patients had been clear of inflammation and treated for aqueous tear deficiency, lipid tear deficiency was further confirmed and treated with Eyefeel (Kao, Inc.), an eye-warming device, 4 times daily for 4 weeks.

RESULTS

Sixteen patients were asymptomatic before LASIK but dryness persisted for 41 +/- 19.3 months. Delayed tear clearance was observed in 15 patients (88.2%) and floppy lids in 12 patients (70.5%). Aqueous tear deficiency was reconfirmed in 16 eyes (53.3%). After Eyefeel treatment, there was a subjective improvement of ocular surface diseases index from 60.6 +/- 10.6 to 25.8 +/- 18.5 (P = .0007). Tear breakup time was improved from 2.4 +/- 3.9 seconds to 7.9 +/- 3.6 seconds (P = .004). There was a tear interference pattern change from a vertical lipid tear deficiency to a horizontal normal in 7 eyes. There was a mean lipid spread time improvement from 1.3 +/- 0.4 sec to 0.8 +/- 0.4 sec (P = .001), and there was a mean lipid thickness improvement from 63.5 +/- 23 nm to 79.5 +/- 27 nm (P = .04).

CONCLUSION

Persistent nature of dry eye after LASIK is attributed to in part to delayed tear clearance, undercorrected aqueous tear deficiency, and nonrecognized lipid tear deficiency.