Expert Consensus Recommendations for the Management of Ocular Surface Inflammation in Patients With Glaucoma.

PRCIS: We have developed through a consensus process 24 clinical recommendations for the comprehensive management of ocular surface inflammation in glaucoma patients, including diagnostic criteria, prevention measures, and treatment strategies according to ocular surface disease severity. PURPOSE: To obtain expert consensus on the diagnosis, prevention, and management of ocular surface inflammation (OSI) in patients with glaucoma. METHODS: An international steering committee of glaucoma and/or ocular surface disease (OSD) experts and a wider faculty of members from the Educational Club of Ocular Surface and Glaucoma (ECOS-G) collaborated to develop clinical recommendations on best practice in the management of OSI in glaucoma patients using a nonanonymous interactive quasi-Delphi process. Clinical recommendations were formulated by the steering committee based on an analysis of the recent literature to determine unmet needs, together with a web-based interactive survey of faculty members' opinion in seven identified areas of OSI management in glaucoma. Topics included (1) diagnosis of OSD, (2) diagnosis of OSI, (3) causes of OSI, (4) impact of OSD/OSI, (5) prevention of OSI, (6) treatment of OSI, and (7) inflammation and the deep structures of the eye. Faculty members were invited to vote on the clinical recommendations, and the steering committee then determined whether consensus had been achieved. RESULTS: Consensus was obtained on 24 clinical recommendations by 80%-100% of faculty members. There was consensus that OSI should be investigated in all glaucoma patients. The main prevention measure in glaucoma patients with pre-existing OSD was the elimination/minimisation of preserved medications, especially BAK-preserved eye drops. A subtractive treatment strategy rather than an additive strategy is recommended according to OSI/OSD severity to improve the ocular health and/or before glaucoma surgery. CONCLUSION: These recommendations for the management of OSI in glaucoma should be useful to guide decision-making in clinical practice.

Allergic Conjunctivitis Management: Update on Ophthalmic Solutions.

PURPOSE OF REVIEW: The aim of this review, is to present an updated revision of topical management of SAC and PAC, based on the available scientific evidence and focused on the impact of ophthalmic solution formulations on eye surface. RECENT FINDINGS: Physicians treating ocular allergy should be aware of tear film and tear film disruption in SAC and PAC, and how eye drop composition and additives affect the physiology of the allergic eye. Seasonal and perennial allergic conjunctivitis (SAC and PAC) are the most frequent causes of ocular allergy (OA), and both conditions are underdiagnosed and undertreated. SAC and PAC are immunoglobulin E (IgE)-mediated hypersensitivity reactions. The additional tear film disruption caused by the release of inflammatory mediators increases and exacerbates the impact of signs and symptoms and may trigger damage of the ocular surface. Comorbidities are frequent, and dry eye disease in particular must be considered. Clinical guidelines for the management of SAC and PAC recommend topical therapy with antihistamines, mast cells stabilizers or dualaction agents as first-line treatment, but care should be taken, as many medications contain other compounds that may contribute to ocular surface damage.

Topical Insulin Eye Drops: Stability and Safety of Two Compounded Formulations for Treating Persistent Corneal Epithelial Defects.

Compounded insulin eye drops were prepared at 1 IU/mL from commercially available subcutaneous insulin by dilution in saline solution or artificial tears. Physicochemical characterization and in vitro tolerance testing in human and conjunctival cells were followed by a 28-day short-term stability study under various conditions. The formulations were isotonic (280-300 mOsm/L), had a pH close to neutral (7-8), medium surface-tension values (<56 MN/m-1), and low (≈1 mPa·s) and medium (≈5 mPa·s) viscosities (compounded normal saline solution and artificial tear-based preparation, respectively). These values remained stable for 28 days under refrigeration. Microbiological stability was also excellent. Insulin potency remained in the 90-110% range in the compounded formulations containing normal saline solution when stored at 2-8 °C for 28 days, while it decreased in those based on artificial tears. Although both formulations were well tolerated in vitro, the compounded insulin diluted in a normal saline solution exhibited better cell tolerance. Preliminary data in humans showed that insulin in saline solution was an effective and safe treatment for persistent corneal epithelial defects. Compounded insulin eye drops diluted in normal saline solution could, therefore, constitute an emergent therapy for the treatment of persistent corneal epithelial defects.

Long-Term Effects of Adipose-Derived Stem Cells for the Treatment of Bilateral Limbal Stem Cell Deficiency.

PURPOSE: To determine the safety and feasibility of human autologous adipose tissue-derived adult mesenchymal stem cells (ASCs) for ocular surface regeneration in patients with bilateral limbal stem-cell deficiency (LSCD). METHODS: A phase IIa clinical trial was designed (https://Clinicaltrials.gov, NCT01808378) with 8 patients, 3 of whom had aniridia, 2 meibomian glands diseases, 2 multiple surgeries and 1 chronic chemical injury. The therapeutic protocol was as follows: 6-mm of central corneal epithelium was removed, 400,000 ASCs were injected into each limboconjunctival quadrant, 400,000 ASCs were suspended over the cornea for 20 min, and finally the cornea was covered with an amniotic membrane patch. RESULTS: No adverse events were detected after a mean of 86,5 months of follow-up. One year after surgery, 6 of the 8 transplants were scored as successful, five patients had improved uncorrected visual acuity (mean of 12 letters), two patients presented epithelial defects (also present at baseline) and the mean percentage of corneal neovascularization was of 28.75% (36.98%, at baseline). Re-examination 24 months after treatment disclosed preserved efficacy in 4 patients. At the last visit (after a mean of 86,5 months of follow up) epithelial defects were absent in all patients although improvement in all of the variables was only maintained in patient 3 (meibomian glands agenesia). CONCLUSION: ASCs are a feasible and conservative therapy for treating bilateral LSCD. The therapeutic effect differs between etiologies and diminishes over time.

Liposomal ozonated oil effectiveness in the signs and symptoms of blepharitis in usual clinical practice.

PURPOSE: To analyze the efficacy of liposomal ozonated oil (Ozonest®) treatment, in patients with blepharitis or blepharoconjunctivitis, in improving the signs and symptoms of the pathology. METHODS: Exploratory, open-label, prospective, single-arm, pre-post comparative pilot study in usual clinical practice, in 20 patients with blepharitis/blepharoconjunctivitis, receiving treatment with liposomal ozonated oil, one drop in each eye, 4 times a day, for 28 days. Main purpose was to assess whether there was a clinically improvement in the blepharitis specific BLISS questionnaire score. Changes in the 12-item OSDI, in eyelid signs of blepharitis assessed by the physicians were also evaluated among other tests, and there was also a subjective evaluation of the treatment by patients. RESULTS: The BLISS score significantly improved from 16.4 before treatment to 11.8 after treatment (p < 0.05). The OSDI score was also significantly improved from 27.5 before treatment to 20.5 after treatment (p < 0.05). All tests conducted before and after treatment showed significant improvement (p < 0.05), except for NIBUT. The treatment received a score of 7 out of 10 by the patients. There were no adverse events in any patient. CONCLUSION: Liposomal ozonated oil treatment showed good efficacy in improving the signs and symptoms of blepharitis/blepharoconjunctivitis, satisfaction of patients, and good safety and tolerability.

Topical insulin, a novel corneal epithelial regeneration agent in dry eye disease.

OBJECTIVE: To evaluate the efficacy of insulin eye drops for dry eye disease in reducing corneal staining and improving symptoms. METHODS: In this retrospective case series, patients with dry eye disease treated with off-label use of insulin eye drops were collected. The main inclusion criterion was diagnosis of dry eye disease with epithelial damage and acceptance of the off-label use of topical insulin. Age, sex, type of dry eye disease, time since diagnosis, previous ocular surgeries, concomitant treatment, best corrected visual acuity, symptoms, conjunctival hyperemia and corneal staining were recorded. Data from the 1 and 3-month visit were included. RESULTS: 16 patients (32 eyes) were treated with insulin (14 females and 2 males; mean age 61.3 ± 16.8 years). 12 patients (71%) were also on autologous serum and 10 patients (63%) on cyclosporine. Symptoms were 3.4 ± 1.3 (range 2-5) when scaled from 0 to 5. Mean hyperemia was 1.0 ± 0.9 (range 0-3) and corneal staining was 2.5 ± 1.3 (range 0-5). After 3 months, 5 patients (31%) referred to be much better, 6 (38%) better, 3 (19%) slightly better and 2 patients (13%) were subjectively similar, mean symptoms being 2.3 ± 1.0 (range 1-4; p = 0.001). Hyperemia was 0.3 ± 0.4 (range 0-1) and corneal staining was 1.1 ± 1.0 (range 0-3; both p < 0.001). Topical insulin was well tolerated with no adverse events. CONCLUSIONS: The excellent results presented in these case series illustrate topical insulin as a promising treatment in dry eye disease with refractory epithelial damage.

NOVATIVE: A Phase II/III, Multicenter, Double-masked, Randomized Study of Cyclosporine A 0.05% and 0.1% Ophthalmic Cationic Emulsion Versus Vehicle in Patients with Vernal Keratoconjunctivitis.

PURPOSE: This study evaluates the efficacy and tolerability of cyclosporine A cationic emulsion (CsA-CE) in patients ≥4 years of age with moderate-to-severe vernal keratoconjunctivitis (VKC). METHODS: This Phase II/III, multicenter, double-masked, dose-ranging study had 2 treatment periods: a 4-week, randomized, vehicle-controlled period in which patients received 0.05% CsA-CE, 0.1% CsA-CE, or vehicle eye drops 4 times daily (period 1) and a 3-month period in which patients received 0.05% CsA-CE or 0.1% CsA-CE 2 or 4 times daily (period 2). The primary efficacy end point was rating of subjective symptoms at day 28 in period 1 per the BenEzra scale. FINDINGS: All groups showed improvement in subjective VKC symptoms at day 28, without a statistically significant difference between 0.05% or 0.1% CsA-CE vs vehicle. Both CsA-CE doses produced statistically significant improvements in corneal fluorescein staining scores vs vehicle at day 28; improvements were evident as early as week 1 and continued through month 1. Progressive reduction in subjective itching was evident after week 1 and continued through month 1. Treatment for an additional 3 months further improved subjective symptoms and objective signs of VKC in both CsA-CE groups. Improvement was most notable with 0.1% CsA-CE in patients with severe keratitis. The safety and tolerability profile is favorable. IMPLICATIONS: Although treatment with 0.05% and 0.1% CsA-CE showed clinical efficacy in alleviating keratitis and itching as early as week 1, with sustained benefit through 1 month, the primary efficacy end point was not met. These findings informed the design of the Phase III trial of 0.1% CsA-CE (Vernal Keratoconjunctivitis Study). CLINICALTRIALS: gov identifier: NCT00328653.

Efficacy and safety of intense pulsed light of upper and lower eyelids in Meibomian gland dysfunction: A prospective multicentric study.

PURPOSE: To demonstrate that intense pulsed light therapy (IPL) of the upper and lower eyelids with meibomian gland expression (MGX) is effective in improving dry eye disease due to meibomian gland dysfunction (MGD). METHODS: Patients with ocular discomfort (Ocular Surface Disease Index -OSDI- above 13) and signs of MGD were recruited. All patients underwent OSDI, visual acuity (VA), intraocular pressure, Schirmer test, meibography, non-invasive tear breakup time (NITBUT), slit-lamp examination (corneal and conjunctival staining, hyperemia, gland expressibility, and meibum quality), tear osmolarity and lipid layer thickness. IPL was performed with Optima IPL (Lumenis Ltd.) following a standardized protocol on upper and lower eyelids of both eyes, with inferior eyelid MGX. Patients received four sessions separated by two weeks each. Four weeks after, examinations were repeated. RESULTS: 160 patients (320 eyes) were included, of which 108 (67.5%) were women and mean age was 59.2 ± 15.08 (range 20-89). After four sessions, VA, OSDI, tear osmolarity, lipid layer thickness, NITBUT, hyperemia, corneal and conjunctival staining, gland expressibility, meibum quality, inferior eyelid Meiboscore and Schirmer test improved (all, p < 0.027). Changes in OSDI, initial and average NITBUT increased with dry eye disease severity (according to OSDI). Increased pre-treatment OSDI, hyperemia, corneal and conjunctival staining and Schirmer test were associated with an improvement in OSDI (all, p < 0.040). No adverse events were noted. CONCLUSIONS: The combination of IPL on upper and lower eyelids with MGX is safe and effective for the treatment of MGD. Patients with severe dry eye disease present greater improvements.

Face mask use and effects on the ocular surface health: A comprehensive review.

In the COVID-19 period, face masks increased exponentially. Several studies suggest that the rise in ocular discomfort symptoms during the pandemic is mostly part of dry eye disease and that these are due to the effect of face masks, resulting in the newly described term MADE, for "mask-associated dry eye". The most commonly proposed mechanism states that wearing a face mask creates an unnatural upward airflow towards the ocular surface during expiration, although the increased temperature, humidity and levels of carbon dioxide of the exhaled air, stress, increased use of video display terminals, as well as changes in the ocular microbiota may contribute. Evidence supports that the use of face masks causes an increase in dry eye disease symptoms, a decreased tear break-up time, corneal epithelial trauma, periocular temperature changes and inflammatory markers secretion. Given that the use of masks may be frequent in some settings in the near future, it is important to establish its effects and consequences on the ocular surface.

A novel osmoprotective liposomal formulation from synthetic phospholipids to reduce in vitro hyperosmolar stress in dry eye treatments.

Dry eye disease (DED) is a worldwide, multifactorial disease mainly caused by a deficit in tear production or increased tear evaporation with an increase in tear osmolarity and inflammation. This causes discomfort and there is a therapeutic need to restore the homeostasis of the ocular surface. The aim of the present work was to develop a biodegradable and biocompatible liposomal formulation from the synthetic phospholipids 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) that is able to reduce the effects of hypertonic stress by helping to restore the lipid layer of the tear film. Liposomes were made using the lipid film hydration method with synthetic phospholipids (10 mg/mL) with and without 0.2% HPMC. They were characterised in terms of size, osmolarity, pH, surface tension, and viscosity. Additionally, the in vitro toxicity of the formulation at 1 and 4 h in human corneal epithelial cells (hTERT-HCECs) and human conjunctival cells (IM-HConEpiC) was determined. Furthermore, osmoprotective activity was tested in a corneal model of hyperosmolar stress. In vivo acute tolerance testing was also carried out in albino New Zealand rabbits by topical application of the ophthalmic formulations every 30 min for 6 h. All the assayed formulations showed suitable physicochemical characteristics for ocular surface administration. The liposomal formulations were well-tolerated in cell cultures and showed osmoprotective activity in a hyperosmolar model. No alterations or discomfort were reported when they were topically administered in rabbits. According to the results, the osmoprotective liposomal formulations developed in this work are promising candidates for the treatment of DED.

Novel Osmoprotective DOPC-DMPC Liposomes Loaded with Antihypertensive Drugs as Potential Strategy for Glaucoma Treatment.

Glaucoma is a group of chronic irreversible neuropathies that affect the retina and the optic nerve. It is considered one of the leading causes of blindness in the world. Although it can be due to various causes, the most important modifiable risk factor is the elevated intraocular pressure (IOP). In this case, the treatment of choice consists of instilling antihypertensive formulations on the ocular surface. The chronicity of the pathology, together with the low bioavailability of the drugs that are applied on the ocular surface, make it necessary to instill the formulations very frequently, which is associated, in many cases, with the appearance of dry eye disease (DED). The objective of this work is the design of topical ocular formulations capable of treating glaucoma and, at the same time, preventing DED. For this, two liposome formulations, loaded with brimonidine or with travoprost, were Tadeveloped using synthetic phospholipids and enriched by the addition of compounds with osmoprotective activity. The proposed formulations not only presented physicochemical characteristics (size, pH, osmolarity, surface tension, and viscosity) and encapsulation efficiency values (EE% of 24.78% and ≥99.01% for brimonidine and travoprost, respectively) suitable for ocular surface administration, but also showed good tolerance in human corneal and conjunctival cell cultures, as well as an in vitro osmoprotective activity. The hypotensive effect of both liposomal formulations was evaluated in normotensive albino New Zealand rabbits, showing a faster and longer lasting reduction of intraocular pressure in comparison to the corresponding commercialized products used as control. According to these results, the hypotensive liposomal formulations combined with osmoprotective agents would result in a very promising platform for the treatment of glaucoma and the simultaneous protection of the ocular surface.

Liposomal Ozonated Oil in Ocular Infections: A Review of Preclinical and Clinical Studies, Focusing on Its Antiseptic and Regenerative Properties.

Ozonated oil has shown antimicrobial, anti-inflammatory and regenerative properties that make it useful in the prevention of infectious diseases and also as an adjuvant in wound-healing management. This review brings together most aspects of the use of liposomal ozonated oil for ocular infections and regeneration of the ocular surface. A search was performed in PubMed, Medline, Web of Science and Cochrane Library for studies published by June 2021. Search terms were combined to sort out papers on the properties and use of ozonated oil in ocular infections. A total of 25 publications were selected for this review on the composition, mechanism of action, restorative action, and preclinical and clinical studies of liposomal ozonated oil focused on ocular infections. In patients with complicated corneal pathology, liposomal ozonated oil has been found to restore corneal ulcers and improve keratitis. In patients with ocular pathologies involving inflammation and infections, liposomal ozonated oil has been found to improve and almost completely restore the signs of vernal, granulomatous and even adenoviral conjunctivitis. Liposomal ozonated oil has also been found to be effective in reducing ocular microbial flora. In conclusion, liposomal ozonated oil has an antiseptic and regenerative effect on corneoconjunctival tissues. It has demonstrated efficacy and safety profile for its use in ocular infections and can be considered as a suitable supportive strategy both alone and combined with other antimicrobial agents.

Intense pulsed light-based treatment for the improvement of symptoms in glaucoma patients treated with hypotensive eye drops.

BACKGROUND: Ocular surface disease in glaucoma patients is a significant ocular co-morbidity that can affect 40% to 59% of these patients worldwide. The current study was aimed at evaluating the potential clinical benefit of an intense pulsed light (IPL)-based treatment in glaucomatous patients with ocular surface disease due to prolonged hypotensive eyedrop treatments. To our knowledge, this is the first series analyzing the therapeutic effect of this treatment option in this type of patients. METHODS: This non-comparative prospective case series study enrolled a total of 30 glaucoma patients ranging in age from 57 to 94 years old and treated with hypotensive eyedrops for years with dry eye symptomatology. All patients received four sessions of IPL treatment using the Optima IPL system (Lumenis, Yokneam, Israel) adjusted to the official optimized Lumenis setting. Changes in symptomatology, corneal staining, conjunctival hyperemia, non-invasive break-up time (NIBUT), tear osmolarity, tear meniscus height (TMH), meiboscore and meibomian gland expressibility was analyzed after treatment. RESULTS: Statistically significant reductions were observed after IPL treatment in the symptomatology scores measured with different questionnaires [ocular surface disease index (OSDI), standard patient evaluation of eye dryness (SPEED) and symptom assessment questionnaire in dry eye (SANDE)] as well as with the visual analogue scale (P < 0.001). Mean change in OSDI was - 15.0 ± 11.3. A significant reduction was found after treatment in the corneal staining score (P < 0.001). A significant reduction was found in tear film meniscus height (P = 0.012), as well as in tear film osmolarity (P = 0.001). A significant reduction was also found in meibomian gland expressibility (P = 0.003), changing the percentage of grade 3 eyes from 44.4% before IPL to 17.2% after treatment. CONCLUSIONS: IPL therapy combined with meibomian gland expression (MGX) seems to be an effective option to improve symptomatology in glaucomatous patients with ocular surface disease due to prolonged hypotensive eyedrop treatments, with an additional improvement in clinical signs, such as tear osmolarity and corneal staining.

Artificial Tears: Biological Role of Their Ingredients in the Management of Dry Eye Disease.

Dry eye disease (DED) is the most common ocular surface disease, characterized by insufficient production and/or instability of the tear film. Tear substitutes are usually the first line of treatment for patients with DED. Despite the large variety of tear substitutes available on the market, few studies have been performed to compare their performance. There is a need to better understand the specific mechanical and pharmacological roles of each ingredient composing the different formulations. In this review, we describe the main categories of ingredients composing tear substitutes (e.g., viscosity-enhancing agents, electrolytes, osmo-protectants, antioxidants, lipids, surfactants and preservatives) as well as their effects on the ocular surface, and we provide insight into how certain components of tear substitutes may promote corneal wound healing, and/or counteract inflammation. Based on these considerations, we propose an approach to select the most appropriate tear substitute formulations according to the predominant etiological causes of DED.

Effect of Face Mask on Tear Film Stability in Eyes With Moderate-to-Severe Dry Eye Disease.

PURPOSE: The purpose of this study was to evaluate whether tear film stability worsens with the use of masks in patients with dry eye disease, objectively analyzing the tear film stability using noninvasive tear film breakup time (NITBUT) with and without a face mask. METHODS: A cross-sectional study including patients with moderate or severe dry eye disease was conducted. Tear stability was measured using an Oculus Keratograph 5M (Oculus, Wetzlar, Germany), which records NITBUT, both first and average NITBUT. Two measurements were taken: an initial measurement with a mask and a second measurement after 10 minutes without wearing the face mask. RESULTS: Thirty-one patients were included with a mean age of 57.6 ± 11.7 years (range 31-80) and 30 being female (97%). Mean first NITBUT with face mask was 6.2 ± 3.8 seconds (range 2.0-19.8), which increased to 7.8 ± 5.6 seconds (range 2.3-24.0) without the use of mask (P = 0.029), differences being -1.6 ± 0.7 seconds (CI 95% -3.1075 to -0.1770). Mean average NITBUT with a face mask was 12.3 ± 4.8 seconds (range 4.0-19.4) and increased to 13.8 ± 5 seconds (range 5.5-24.0) without the use of mask (P = 0.006), mean difference being -1.5 ± 0.5 seconds (CI 95% -2.5290 to -0.4458). CONCLUSIONS: Face mask use decreases tear film stability in patients with moderate-to-severe dry eye.

Quantification of a panel for dry-eye protein biomarkers in tears: A comparative pilot study using standard ELISA and customized microarrays.

Purpose: This paper examines the tear concentration of cystatin S (CST4), calcyclin (S100A6), calgranulin A (S100A8), and matrix metalloproteinase 9 (MMP9), and the correlation between biomarker expression, clinical parameters, and disease severity in patients suffering from dry eye (DE). A comparison of the results is obtained via ELISA tests and customized antibody microarrays for protein quantification. Methods: This single-center, observational study recruited 59 participants (45 DE and 14 controls). Clinical evaluation included an Ocular Surface Disease Index (OSDI) questionnaire, a tear osmolarity (OSM) test, the Schirmer test (SCH), tear breakup time (TBUT), fluorescein (FLUO) and lissamine green (LG) corneal staining, and meibomian gland evaluation (MGE). Tear concentrations of CST4, S100A6, S100A8, and MMP9 were measured using standard individual ELISA assays. The levels of CST4, S100A6, and MMP9 were also measured using customized multiplexed antibody microarrays. Correlations between variables were evaluated, and a significance level was p value <0.05. Results: The quantification of tear protein biomarkers with ELISA showed that the concentration of CST4 was significantly (2.14-fold) reduced in tears of DE patients in comparison with control (CT) subjects (p < 0.001). S100A6 and S100A8 concentrations were significantly higher in the tears of DE patients (1.36- and 2.29-fold; p < 0.001 and 0.025, respectively) in comparison with CT. The MMP9 level was also higher in DE patients (5.83-fold), but not significantly (p = 0.22). The changes in CST4 and S100A6 concentrations were significantly correlated with dry eye disease (DED) severity. Quantification of CST4, S100A6, and MMP9, using antibody microarrays, confirmed the ELISA results. Similar trends were observed: 1.83-fold reduction for CST4 (p value 0.01), 8.63-fold increase for S100A6 (p value <0.001) and 9.67-fold increase for MMP9 (p value 0.94), but with higher sensitivity. The biomarker concentrations were significantly associated with the signs and symptoms related with DED. Conclusions: S100A6, S100A8, and CST4 diagnostic biomarkers strongly correlate with DED clinical parameters. S100A6 and CST4 are also useful for grading DE severity. The multiplexed antibody microarray technique, used here for tear multi-marker quantification, appears more sensitive than standard ELISA tests.

Current Knowledge in Allergic Conjunctivitis.

Allergic conjunctivitis is a disease of increasing prevalence that affects both children and adults and causes significant deterioration of their quality of life and sometimes irreversible visual damage. There are various forms of the disease, some are allergen-induced such as seasonal and perennial allergic conjunctivitis, giant papillary conjunctivitis, and contact allergic blepharoconjunctivitis, whereas others are not always explained by allergen exposure, such as vernal keratoconjunctivitis and atopic keratoconjunctivitis. We review their clinical course, characteristics, and differential diagnosis, and highlight recent advances in their pathophysiology and treatment.