Optical characterization and through-focus performance of two advanced monofocal intraocular lenses.

PURPOSE: To compare the refractive power profile, subjective depth-of-field and objective optical quality of two advanced monofocal intraocular lenses (IOLs) designed to improve intermediate vision. METHODS: This prospective study evaluated forty-six eyes of twenty-three patients, aged 54-68 years, binocularly implanted with two monofocal enhanced intraocular lenses (IOLs), the Tecnis Eyhance and the Physiol Isopure. Subjective through-focus visual acuity curves were obtained by placing trial lenses in front of the eye while wearing its best spherical-cylindrical correction for distance. Objective optical quality was defined as the area under the modulation transfer function, calculated from the wavefront maps measured with a high-resolution aberrometer. The optical design of both lenses was compared based on their refractive power profiles measured with the lenses immersed in saline solution. RESULTS: Both lenses have progressive aspherical geometries, in which the sagittal power decreases rapidly from the center to the edge of the optical zone. Mean monocular through-focus curves show a best corrected distance visual acuity of - 0.02 logMAR with both lenses. Through-focus visual acuity was marginally higher for the Eyhance, with a difference of 1 letter at the defocus position of - 0.5D and 3 letters between - 1.0D and - 2.0D. Objective assessment of optical quality revealed only a difference of about 2 points in MTF area at distance. CONCLUSION: Both IOLs use a similar approach to improve intermediate vision. The Eyhance showed marginally better subjective performance than the Isopure at the target vergences between - 1.00D and - 2.00D, although these results did not reach statistical significance and were not replicated by the objective findings.

Idiopathic intracranial hypertension and oxaliplatin: a causal association?

We report a case of a 54-year-old woman presented at the emergency service with complaints of transitory visual obscurations for four days, and headache, nausea and occasional vomiting in the last two months. She had been diagnosed of colorectal cancer one year ago and she was on treatment with oxaliplatin on a FOLFOX schedule. On ophthalmic examination, the vision was of 20/20 in both eyes and bilateral disc swelling was noted. The neurologic examination was normal. Magnetic resonance revealed no changes. A diagnostic lumbar puncture demonstrated an elevated opening pressure of 290 mm H2O with normal compounds. Due to the suspicion of ocular toxicity, oxaliplatin treatment was stopped. Treatment with oral acetazolamide was started and maintained for one month. In three weeks ocular and systemic symptoms totally disappeared and disc swelling gradually improved in the following months. Ocular toxicity has been reported as an infrequent adverse effect of oxaliplatin, but intracranial idiopathic pressure has not yet been described. Findings in this case suggest that oxaliplatin could be the cause for these symptoms. As the use of oxaliplatin is increasing as first-line treatment in colorectal cancer, we have to be alert to its potential toxicity.

Analysis of Wavefront Data Obtained With a Pyramidal Sensor in Pseudophakic Eyes Implanted With Diffractive Intraocular Lenses.

PURPOSE: To investigate the clinical validity of using wavefront measurements obtained with a recently available pyramidal aberrometer to assess the optical quality of eyes implanted with diffractive intraocular lenses (IOLs). METHODS: Individual biometric data were used to create models of pseudophakic eyes implanted with two diffractive IOLs. Their synthetic wavefronts were calculated by ray-tracing with near infrared wavelength (0.85 µm). Comparisons of the through-focus visual acuity of 12 pseudophakic eyes were obtained with three different methods: clinical defocus curves; simulated defocus curves calculated from ray-tracing in the customized model eyes; and through-focus simulated defocus curves calculated from the wavefront data measured with a pyramidal aberrometer. RESULTS: Image quality calculated from wavefront data obtained by ray-tracing with 0.85 µm wavelength, without scaling the phase to 0.55 µm, resulted in a significantly different through-focus curve compared to the reference values. Even so, after scaling of the wavefront data to 0.55 µm, the defocus curves calculated from the wavefronts measured with the pyramidal aberrometer did not match the shape and the depth of field of the clinical defocus curves or the theoretical expected values. CONCLUSIONS: Correcting for the longitudinal chromatic aberration of the eye when measuring the wavefront of eyes implanted with diffractive IOLs under near infrared light only accounts for the best focus shift due to the longitudinal chromatic aberration, but not for the wavelength dependence of the diffractive element. The pyramidal sensor does not seem to properly sample the slopes of a wavefront measured from a pseudophakic eye implanted with a presbyopia-correcting diffractive IOL to a clinically acceptable level. [J Refract Surg. 2023;39(7):438-444.].

Gene expression signatures in conjunctival fornix aspirates of patients with dry eye disease associated with Meibomian gland dysfunction. A proof-of-concept study.

BACKGROUND: Meibomian gland dysfunction (MGD) is one of the most common conditions in ophthalmic practice and the most frequent cause of evaporative dry eye disease (DED). However, the immune mechanisms leading to this pathology are not fully understood and the diagnostic tests available are limited. Here, we used the nCounter technology to analyze immune gene expression in DED-MGD that can be used for developing diagnostic signatures for DED. METHODS: Conjunctival cell samples were obtained by aspiration from patients with DED-MGD (n = 27) and asymptomatic controls (n = 22). RNA was purified, converted to cDNA, preamplified and analyzed using the Gene Expression Human Immune V2 panel (NanoString), which includes 579 target and 15 housekeeping genes. A machine learning (ML) algorithm was applied to design a signature associated with DED-MGD. RESULTS: Forty-five immune genes were found upregulated in DED-MGD vs. controls, involved in eight signaling pathways, IFN I/II, MHC class I/II, immunometabolism, B cell receptor, T Cell receptor, and T helper-17 (Th-17) differentiation. Additionally, statistically significant correlations were found between 31 genes and clinical characteristics of the disease such as lid margin or tear osmolarity (Pearson's r < 0.05). ML analysis using a recursive feature elimination (RFE) algorithm selected a 4-gene mRNA signature that discriminated DED-MGD from control samples with an area under the ROC curve (AUC ROC) of 0.86 and an accuracy of 77.5%. CONCLUSIONS: Multiplexed mRNA analysis of conjunctival cells can be used to analyze immune gene expression patterns in patients with DED-MGD and to generate diagnostic signatures.

Optimized Artificial Intelligence for Enhanced Ectasia Detection Using Scheimpflug-Based Corneal Tomography and Biomechanical Data.

PURPOSE: To optimize artificial intelligence (AI) algorithms to integrate Scheimpflug-based corneal tomography and biomechanics to enhance ectasia detection. DESIGN: Multicenter cross-sectional case-control retrospective study. METHODS: A total of 3886 unoperated eyes from 3412 patients had Pentacam and Corvis ST (Oculus Optikgeräte GmbH) examinations. The database included 1 eye randomly selected from 1680 normal patients (N) and from 1181 "bilateral" keratoconus (KC) patients, along with 551 normal topography eyes from patients with very asymmetric ectasia (VAE-NT), and their 474 unoperated ectatic (VAE-E) eyes. The current TBIv1 (tomographic-biomechanical index) was tested, and an optimized AI algorithm was developed for augmenting accuracy. RESULTS: The area under the receiver operating characteristic curve (AUC) of the TBIv1 for discriminating clinical ectasia (KC and VAE-E) was 0.999 (98.5% sensitivity; 98.6% specificity [cutoff: 0.5]), and for VAE-NT, 0.899 (76% sensitivity; 89.1% specificity [cutoff: 0.29]). A novel random forest algorithm (TBIv2), developed with 18 features in 156 trees using 10-fold cross-validation, had a significantly higher AUC (0.945; DeLong, P < .0001) for detecting VAE-NT (84.4% sensitivity and 90.1% specificity; cutoff: 0.43; DeLong, P < .0001) and a similar AUC for clinical ectasia (0.999; DeLong, P = .818; 98.7% sensitivity; 99.2% specificity [cutoff: 0.8]). Considering all cases, the TBIv2 had a higher AUC (0.985) than TBIv1 (0.974; DeLong, P < .0001). CONCLUSIONS: AI optimization to integrate Scheimpflug-based corneal tomography and biomechanical assessments augments accuracy for ectasia detection, characterizing ectasia susceptibility in the diverse VAE-NT group. Some patients with VAE may have true unilateral ectasia. Machine learning considering additional data, including epithelial thickness or other parameters from multimodal refractive imaging, will continuously enhance accuracy. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Prospective evaluation of intense pulsed light treatment for meibomian gland dysfunction and blepharitis due to ocular rosacea

Background: Ocular rosacea is a common skin condition leading to dry eye that is difficult to manage. Objectives: To estimate the efficacy and safety of a new intense pulsed light device, Thermaeye Plus, for meibomian gland dysfunction and blepharitis due to ocular rosacea. Materials & Methods: This prospective, longitudinal study included 74 eyes of 37 consecutive patients with ocular rosacea, with mean age of 45.6±11.7 years. Four consecutive sessions were undertaken, including14 flashes with 10 J/cm² on the periocular area and facial cheeks on Day 1, 14, 28, and 49. Clinical evaluation was based on: ocular surface disease index (OSDI) and symptom score questionnaires, quality of live and facial severity degree, non-invasive tear meniscus height, non-invasive tear break up time, corneal fluorescein staining and eyelid margin and meibomian gland assessment. Adverse effects on the eye and periocular area, and systemic complications were evaluated. Results: The OSDI questionnaire showed a decrease in symptoms, achieving normal values in 91.9% of patients. The symptom score showed amelioration, with the most significant changes relating to dryness, foreign body sensation, light sensitivity, and pain. Longitudinal analysis showed the most significant improvement between baseline at Day 1 and 49. All eyelid signs improved, most significantly for telangiectasia/vascularity and blepharitis, leading to a 78% clearance of facial rosacea and 81.1% reduction of flushing. In total, 100% of the patients reported an improvement in their quality of life after treatment and 94.6% a very significant improvement (p<0.001). Conclusion: These results demonstrate that Thermaeye Plus is an effective and safe treatment for ocular rosacea.

Impact of Systemic Comorbidities on Ocular Hypertension and Open-Angle Glaucoma, in a Population from Spain and Portugal.

Open-angle glaucoma (OAG), the most prevalent clinical type of glaucoma, is still the main cause of irreversible blindness worldwide. OAG is a neurodegenerative illness for which the most important risk factor is elevated intraocular pressure (IOP). Many questions remain unanswered about OAG, such as whether nutritional or toxic habits, other personal characteristics, and/or systemic diseases influence the course of glaucoma. As such, in this study, we performed a multicenter analytical, observational, case-control study of 412 participants of both sexes, aged 40-80 years, that were classified as having ocular hypertension (OHT) or OAG. Our primary endpoint was to investigate the relationship between specific lifestyle habits; anthropometric and endocrine-metabolic, cardiovascular, and respiratory events; and commonly used psychochemicals, with the presence of OHT or OAG in an ophthalmologic population from Spain and Portugal. Demographic, epidemiological, and ocular/systemic clinical data were recorded from all participants. Data were analyzed using the R Statistics v4.1.2 and RStudio v2021.09.1 programs. The mean age was 62 ± 15 years, with 67-80 years old comprising the largest subgroup sample of participants in both study groups. The central corneal thickness (ultrasound pachymetry)-adjusted IOP (Goldman tonometry) in each eye was 20.46 ± 2.35 and 20.1 ± 2.73 mmHg for the OHT individuals, and 15.8 ± 3.83 and 16.94 ± 3.86 mmHg for the OAG patients, with significant differences between groups (both p = 0.001). The highest prevalence of the surveyed characteristics in both groups was for overweight/obesity and daily coffee consumption, followed by psychochemical drug intake, migraine, and peripheral vasospasm. Our data show that overweight/obesity, migraine, asthma, and smoking are major risk factors for conversion from OHT to OAG in this Spanish and Portuguese population.

Prospective evaluation of a new intense pulsed light, thermaeye plus, in the treatment of dry eye disease due to meibomian gland dysfunction.

PURPOSE: This study aims to estimate the efficacy and safety of a new intense pulsed light (IPL) Thermaeye Plus for dry eye disease (DED) secondary to meibomian gland dysfunction (MGD). PATIENTS AND METHODS: This is a prospective, longitudinal study of patients with moderate to severe MGD. Treatment consisted of 4 consecutive IPL sessions, 12 flashes with the same energy 8J/cm2 on the periocular area at days 1, 14, 28, and 49. All patients were evaluated before each IPL sessions and 1 and 4 months after the last session. Measuring: Symptoms score and OSDI questionnaire, Non-invasive tear meniscus height (NITMH), Non-invasive break up (NITBUT), Tear osmolarity (TO), Corneal fluorescein staining (CFS) and Eyelid margin and Meibomian gland assessment. The adverse effects on the eye, periocular area, and systemic complications were evaluated. All types of skin pigmentation (Fitzpatrick scale I to VI) were included. RESULTS: The study included 44 consecutive patients (88 eyes), 40 males and 48 females, with a mean age of 52.5±13.6 years, ranging from 22 to 78 years. Significant improvements were observed in single and total signs and symptoms. The most significant changes were observed in dryness, foreign body sensation (p<0.001), and pain (p<0.005). The OSDI questionnaire showed a significant decrease in total symptoms (p<0.003). The percentage of patients with a normal index <13, improved from 23.8% (10 patients) at baseline to 80.9% (34 patients) at last visit, after 23 weeks. Clinical sings also improved, more than 90%, stand out telangiectasia and blepharitis (p<0.002, and p<0.0005, respectively). No statistical differences between age (<40y, 40-60y, and >60y) and gender were observed. The clinical improvement began after the second and third week after the first IPL session, until the end of the IPL treatment (D49). After that, the results maintained stable until the last visit, after 11 weeks. No complications were reported locally, nor in the periocular area as well as systemically. CONCLUSION: Thermaeye Plus, a new IPL for ophthalmic use, is a safe and effective treatment in patients with DED due to MGD, showing improvement from the second week of treatment and maintaining until the last visit, 4 months after the last IPL session (23 weeks of total follow-up). Patients with pigmented skin (Fitzpatrick V or VI) have been treated with no side effects. It is relevant, especially to apply in brown-dark skin populations since complications with other IPL devices have been reported.

Correlation of axon size and myelin occupancy in rats prenatally exposed to methamphetamine.

The abuse of methamphetamine (MA) and other psychostimulants is a social and medical problem. In particular, the use of these drugs by pregnant women results in an increased number of children exposed prenatally to psychostimulants. Our previous work has demonstrated that prenatal exposure to MA affects the normal development of the rat visual system due to alterations of biochemical mechanisms and oxidative stress. It was also demonstrated that prenatal exposure to MA affects the dopaminergic system of the rat retina and optic nerve (ON) myelination. The present work was conducted to evaluate the effects of prenatal exposure to MA on the development of the ON in terms of axon growth and the myelin sheath. Pregnant female rats were given 5 mg/kg/day MA, subcutaneously (s.c.), in 0.9% saline from gestational day (GD) 8 to 22. The pair-fed control group was injected s.c. with an isovolumetric dose of 0.9% saline. Qualitative analysis was performed using representative electron ultramicrographs. Quantitative analysis was performed at an electron microscopic level on ON cross sections; parameters measured included myelinated/unmyelinated ratio, outer axon mean area, inner axon mean area, myelin mean area, myelin occupancy and distribution of axons by size. The ON of prenatally MA-exposed rats presented a higher rate of deformed axons and slighter lamellar separation. At PND 21, the average outer axon area of MA-treated males was significantly reduced. The average inner axon area only showed a significant difference between MA and control males for axons with an area of less than 0.3 microm(2). The average myelin area of MA-treated males was significantly reduced, and in MA-treated females was only significantly reduced in axons with an area of less than 0.3 microm(2). The percentage of myelin occupancy was significantly affected in MA-treated males, and in MA-treated females in the group of axons with an area of more than 0.3 microm(2). At PND 14 no significant differences were found between MA and control groups. The spectrum of ON myelinated axon size of MA-treated animals was shifted to the left at PND 14 and PND 21 for both genders. These results are in agreement with previous animal studies of prenatal and perinatal exposure to drugs of abuse. Taken together, these data indicate that the ON is vulnerable to early exposure to MA which causes developmental changes and may interfere with the functioning of the visual system.

Comparative evaluation of Scheimpflug tomography parameters between thin non-keratoconic, subclinical keratoconic, and mild keratoconic corneas.

PURPOSE: To evaluate and compare the topographic and topometric parameters, thickness profile data, and data from enhanced elevation maps of thin non-keratoconic, subclinical keratoconic, and mild keratoconic corneas with the Pentacam Scheimpflug corneal tomography and to study the usefulness of different parameters to differentiate keratoconus from topographically normal thin corneas. METHODS: The study included 30 eyes with subclinical keratoconus, 30 eyes with mild-stage keratoconus, and 54 healthy eyes with minimal pachymetry ≤500 µm, with a mean age of 21.19 ± 2.97, 21.75 ± 1.93, and 21.5 ± 2.95 years, respectively. The area under the receiver operating characteristic curves was used to analyze the diagnostic significance of the Pentacam parameters. RESULTS: The anterior and posterior corneal elevations, pachymetric progression, the percentage of thickness increase measurements, overall D value, and topometric indices were statistically significantly higher in subclinical and mild keratoconic corneas than in normal eyes with thin cornea (p < 0.05). All these parameters had sufficient strength (area under the receiver operating characteristic curves >0.90) to differentiate clinical keratoconus. Posterior elevation showed the excellent area under the receiver operating characteristic curves with 100% sensitivity and 100% specificity for this purpose. However, among all parameters studied, the anterior elevation (0.935) showed the excellent area under the receiver operating characteristic curves to differentiate subclinical keratoconus, followed by posterior elevation (0.897), index of height decentration (0.887), and D value (0.882). CONCLUSION: The parameters derived from the Scheimpflug device, such as corneal elevations and overall D value, can effectively differentiate subclinical and clinical keratoconus from non-keratoconic thin cornea eyes. However, the specificity levels of these parameters were relatively limited in the diagnosis of subclinical keratoconus.

Topical plus subconjunctival anaesthesia: foldable intraocular lens implantation in eyes without capsule support through a self-sealing incision.

PURPOSE: To evaluate the clinical outcomes of topical plus subconjunctival anaesthesia for secondary implantation of foldable intraocular lens (IOL) (Ophtec PC 425Y) in eyes without capsule support through a self-sealing incision. METHODS: We reviewed the medical records of 22 patients (22 eyes) who received topical plus subconjunctival anaesthesia for scleral fixation of a foldable IOL through small incision. The scleral incision technique was used for IOL scleral fixation. Twelve eyes had traumatic cataract, seven had postphacoemulsification complications and three were aphakic. We studied visual outcome, intraoperative complications and perioperative pain. Autorefractometry and keratometry measurements and central endothelial cell counts were evaluated 1 day preoperatively and 4 months postoperatively. The level of intraoperative pain was scored on a scale of 1-10, where 1 = no pain and 10 = severe pain. RESULTS: Nineteen patients (86%) tolerated the procedure well, giving pain scores of 1-3, and none required supplemental anaesthesia. The mean age of the patients was 60 years. The postoperative best-corrected visual acuity (BCVA) ranged between 20/100 and 20/25. Four months postoperatively, the mean myopic shift by autorefractometry was -1.25 dioptre (D) and the mean postoperative astigmatism was 1.75 D. The mean central corneal endothelial loss at 4 months was 12.24% (range 4.5-17.2%). Five microscopic hyphaema occurred intraoperatively. Four cystoid macular oedema and four peripheral anterior synechia were the only complications, each occurring at the final follow-up. CONCLUSION: Topical plus subconjunctival anaesthesia and scleral fixation of foldable IOL (Ophtec PC 425Y) was safe, quick, required a small incision, led to favourable visual outcomes and minimized the risk of intraoperative and postoperative complications in eyes without capsule support. However, a long-term study of a large population is required to confirm these findings.

Photoscreening for amblyogenic risk factors in 1-year-olds: results from a single center in Portugal over a 9-year period.

PURPOSE: To report the experience of a single center in photoscreening 1-year-olds for amblyogenic risk factors over a 9-year period and to estimate amblyopia prevalence in this population. METHODS: The records of 11,029 children 11-18 months of age who were screened for amblyogenic risk factors at Centro Hospitalar de Entre o Douro e Vouga between 2004 and 2012 were reviewed. Measurements were performed with MTI (until 2008) and plusoptiX S04 (from 2009). The screening results were evaluated according to criteria adapted from Donahue and colleagues. RESULTS: The screening was negative in 8,985 children (82%), positive in 519 (5%), unreadable in 201 (2%), and borderline in 1,324 (12%). The overall positive predictive value (PPV) for the presence of at least one amblyogenic risk factor was 56.8%. The estimated prevalence of meaningful refractive errors in this population was 2.2%; of strabismus, 0.3%. CONCLUSIONS: The rate of unreadable screenings was low. The overall PPV was lower than other large studies, at older ages, but higher than those of the same-age children. Considering the potential benefits of early intervention in preventing the development of amblyopia, this study demonstrates the feasibility of screening 1-year-olds.

Light-distortion analysis as a possible indicator of visual quality after refractive lens exchange with diffractive multifocal intraocular lenses.

PURPOSE: To study the perception of light distortion after refractive lens exchange (RLE) with diffractive multifocal intraocular lenses (IOLs). SETTING: Clínica Oftalmológica das Antas, Porto, Portugal. DESIGN: Retrospective comparative study. METHODS: Refractive lens exchange was performed with implantation of an AT Lisa 839M (trifocal) or 909MP (bifocal toric) IOL, the latter if corneal astigmatism was more than 0.75 diopter (D). The postoperative visual and refractive outcomes were evaluated. A prototype light-distortion analyzer was used to quantify the postoperative light-distortion indices. A control group of eyes in which a Tecnis ZCB00 1-piece monofocal IOL was implanted had the same examinations. RESULTS: A trifocal or bifocal toric IOL was implanted in 66 eyes. The control IOL was implanted in 18 eyes. All 3 groups obtained a significant improvement in uncorrected distance visual acuity (UDVA) (P < .001) and corrected distance visual acuity (CDVA) (P = .001). The mean uncorrected near visual acuity (UNVA) was 0.123 logMAR with the trifocal IOL and 0.130 logMAR with the bifocal toric IOL. The residual refractive cylinder was less than 1.00 D in 86.7% of cases with the toric IOL. The mean light-distortion index was significantly higher in the multifocal IOL groups than in the monofocal group (P < .001), although no correlation was found between the light-distortion index and CDVA. CONCLUSIONS: The multifocal IOLs provided excellent UDVA and functional UNVA despite increased light-distortion indices. The light-distortion analyzer reliably quantified a subjective component of vision distinct from visual acuity; it may become a useful adjunct in the evaluation of visual quality obtained with multifocal IOLs. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

Corneal biomechanical properties in different ocular conditions and new measurement techniques.

Several refractive and therapeutic treatments as well as several ocular or systemic diseases might induce changes in the mechanical resistance of the cornea. Furthermore, intraocular pressure measurement, one of the most used clinical tools, is also highly dependent on this characteristic. Corneal biomechanical properties can be measured now in the clinical setting with different instruments. In the present work, we review the potential role of the biomechanical properties of the cornea in different fields of ophthalmology and visual science in light of the definitions of the fundamental properties of matter and the results obtained from the different instruments available. The body of literature published so far provides an insight into how the corneal mechanical properties change in different sight-threatening ocular conditions and after different surgical procedures. The future in this field is very promising with several new technologies being applied to the analysis of the corneal biomechanical properties.

Efficacy of 3 different artificial tears for the treatment of dry eye in frequent computer users and/or contact lens users.

PURPOSE: To compare the efficacy of 3 different artificial tears (AT) acting primarily in one of the 3 tear film layers (Tears Again®, lipidic; Opticol®, aqueous; Optive®, mucin) in recovering the tear film changes in patients with dry eye symptoms due to external causes. METHODS: A total of 27 patients, with dry eye symptoms associated with extra hours of computer or contact lenses use, were randomized to 4 treatment groups: A received Tears Again®; B received Optive®; C received Opticol®; D received no treatment (control). Patients were observed in 3 visits: day 0, day 7, and day 30. Tear break-up time (TBUT) and Schirmer tests and the Ocular Surface Disease Index were performed. Data analysis was performed. RESULTS: There were no significant differences between the groups. From day 0 to day 30, there was a decrease in the number of eyes with abnormal TBUT (not significant) and Schirmer (significant in A, B, D; p<0.031). There was an increase in the average TBUT for all groups (significant in A, C; p<0.001) and a decrease in the average Schirmer value in groups B, C, and D (not significant) and an increase in group A (p = 0.002). There was a decrease in the average Ocular Surface Disease Index value in all groups (p<0.045). CONCLUSIONS: All AT were efficient at recovering the tear film, but those acting primarily on the internal and intermediate layer led to a mild decline on lachrymal production. An association of different kinds of AT acting on each layer can be the best treatment for corneal surface diseases affecting eye lubrication.