Contact lens-induced dry eye (CLIDE) is a condition in which CL wear directly reduces tear film stability, causing ocular discomfort, visual disturbances, and corneal/conjunctival epithelial damage.
Dry eye is defined as “a chronic disease of the tears and ocular surface due to various factors, accompanied by ocular discomfort and visual disturbance” 7). CLIDE is a condition where CL wear is the primary cause among the “various factors” in this definition, and it involves a complex interplay of CL material, fitting, care solutions, and wearing time.
Many epidemiological studies have reported that CL use increases the risk of dry eye symptoms 7). On the other hand, the Osaka Study, based on dry eye diagnostic criteria, did not find CL wear to be a significant risk factor 7). While CLs can induce dry eye symptoms, evidence is inconsistent as to whether they are a risk factor for developing dry eye that meets diagnostic criteria.
Even with the widespread use of silicone hydrogel (SiHy) lenses today, approximately half of CL wearers are reported to have dry eye symptoms 7). The situation has changed with the evolution of materials, and the type of CLs used varies depending on the study period, which has a significant impact. TFOS DEWS III explicitly lists CL wear as a risk factor for dry eye and recommends changing CL material, design, replacement frequency, and care solutions for managing CLIDE 1).
The number of CL wearers worldwide is estimated to reach about 300 million 3), and the combined effect of digital devices and CL wear is a major risk for CLIDE, especially in young adults 4).
CLs affect all layers of the tear film: the lipid layer, aqueous layer, and mucin layer. Specifically, the following mechanisms are important.
If dry eye symptoms become chronic due to CL wear, switching to refractive surgery (ICL, LASIK, SMILE) may be an option. ICL has the advantage of causing less postoperative dry eye because it does not ablate the cornea. However, suitability should be determined by an ophthalmologist, so it is advisable to first try to control symptoms and consult if that proves difficult.
The main subjective symptoms of CLIDE are as follows:
| Subjective symptom | Characteristics/Frequency |
|---|---|
| Dryness/desert-like sensation | Worsens in the evening or after prolonged wear |
| Foreign body sensation/grittiness | Prominent in evaporative dry eye type |
| Redness | Mild to moderate, palpebral and bulbar conjunctiva |
| Blurred vision/visual fluctuation | Temporarily improves after blinking |
| Eye fatigue | Worsens after VDT work |
| Burning or stinging sensation | Worsened by eye drops or wind |
If all symptoms of redness, discharge, and pain are present, suspect infectious keratitis. Immediately remove the contact lens and seek medical attention.
Fluorescein staining reveals patterns characteristic of CLIDE.
Smile-Mark Punctate Superficial Keratopathy (SCL)
Location: Inferior pupillary area, matching the shape of a smiling mouth.
Cause: Occurs in patients with pre-existing dry eye when wearing SCL, due to reduced tear fluid under the lens.
Course: Managed with dry eye eye drops (diquafosol, hyaluronic acid). Advise early removal after evening.
3 and 9 O'Clock Staining (HCL)
Location: Localized to the 3 and 9 o’clock positions of the corneal limbus.
Cause: During blinking, HCL moves about 2 mm vertically, causing local dryness when tears are drawn in from the 3 and 9 o’clock directions.
Course: Mild cases heal in 3–5 days. Progression may leave corneal opacity.
Diffuse Punctate Superficial Keratopathy (HCL/SCL)
Location: Almost uniform across the entire cornea
Cause: Oxygen deficiency due to CL wear, or overall dryness from tear film instability
Course: Heals in 4–5 days with CL discontinuation and eye drops
Other findings include reduced tear meniscus (≤0.25 mm), shortened tear break-up time (BUT ≤5 seconds), and tear film instability due to lipid deposits in SiHy lens wearers.
| CL Type | Association with CLIDE | Main Issues |
|---|---|---|
| HCL (RGP) | 3 and 9 o’clock staining | Mechanical irritation and local dryness during blinking |
| HEMA-based SCL | Diffuse SPK and hypoxia | Corneal hypoxia due to low Dk/t |
| SiHy SCL | Smile mark SPK/SEAL | SEAL due to lipid deposits and hardness |
| Color CL | Donut-shaped SPK | Tear film instability at the pigmented area |
Even after the widespread use of SiHy lenses, dry eye symptoms in wearers have not improved. The hydrophobicity of SiHy material makes it prone to lipid deposits, and the lipids adhering to the surface destabilize the lipid layer of the tear film. While conventional HEMA lenses mainly caused protein deposits, SiHy lenses produce deposits primarily composed of phospholipids and neutral lipids2).
TFOS DEWS III reports that lipid-containing artificial tears (lipomimetic eye drops) are effective in improving symptoms and corneal staining in CL wearers1).
During screen work, blink rate decreases markedly from about 16 times per minute to 5–7 times per minute, and incomplete blinks also increase4). Incomplete blinks prevent uniform spreading of the oil layer, leading to increased tear evaporation4). When VDT work and CL wear are combined, CLIDE is significantly exacerbated4).
VDT work is a risk factor for dry eye, with reports indicating that the risk of developing dry eye is 1.94 times higher in those who perform VDT work for more than 8 hours per day7). For CL wearers with long VDT work hours, it should be kept in mind that CLIDE is more likely to develop or worsen.
Preservatives such as benzalkonium chloride (BAK) can cause goblet cell damage and reduce the production of secretory mucins5). Mucin reduction leads to a tear film breakup pattern of poor wettability (spot/dimple break), which worsens CLIDE. Switching to preservative-free care products and eye drops can help reduce mucin damage.
Ring-shaped staining (which became a problem around 2010) has been reported with incompatibility between MPS (multipurpose solution) and SiHy lenses, so attention must be paid to the combination of care product type and lens material.
Daily disposable lenses require no lens care, have no risk of case contamination, and minimize accumulation of protein and lipid deposits. Care product-related complications and giant papillary conjunctivitis are less likely to occur. However, dry eye-related smile mark punctate keratopathy can still occur with daily disposable lenses, so it is important to also manage dry eye with eye drops and VDT work habits.
Based on the Japanese dry eye diagnostic criteria (2016 revision, Dry Eye Society). A definitive diagnosis of dry eye is made when both of the following two items are met7).
For the diagnosis of CLIDE, it is recommended to compare BUT while wearing CL and BUT after removing CL. If BUT is significantly shortened during CL wear, it is highly likely that CL is the trigger.
| Examination | Method/Evaluation Criteria | Association with CLIDE |
|---|---|---|
| BUT (Tear Film Breakup Time) | Fluorescein staining → abnormal if 5 seconds or less | Comparison between during CL wear and after removal |
| Fluorescein staining | Epithelial damage pattern assessment | Smile mark / 3 and 9 o’clock staining |
| Schirmer test | ≤5 mm/5 min is abnormal | Evaluation of tear secretion volume |
| Tear meniscus observation | ≤0.25 mm is abnormal | Assessment of decreased tear volume during CL wear |
| TFOD evaluation | Tear film breakup pattern upon eye opening | Differentiate between evaporative type and aqueous-deficient type |
In CLIDE, evaporative type (random break) and aqueous-deficient type (spot/dimple break) are common. Pattern evaluation based on TFOD (Tear Film Oriented Diagnosis) directly guides treatment selection7).
| Differential Diagnosis | Key Points for Differentiation |
|---|---|
| Infectious keratitis | Triad of hyperemia, discharge, and pain. Requires urgent management |
| Superior limbic keratoconjunctivitis (SLK) | Conjunctival epithelium also stains (SEALs have no conjunctival staining) |
| Allergic conjunctivitis | Ocular itching, papillary hypertrophy. Seasonal or perennial |
| CL complications (SEAL, GPC, etc.) | Differentiate by fluorescein staining pattern and location |
The Dry Eye Clinical Practice Guideline recommends the use of artificial tears for dry eye in contact lens wearers 7). Depending on patient preference, changing lens material or lens care products, and oral omega-3 fatty acid supplementation are also suggested as treatment options 7) (strength of recommendation: weak, evidence level C).
TFOS DEWS III presents a stepwise treatment algorithm for evaporative dry eye disease including CLIDE 1). The algorithm escalates from lifestyle modification to eye drop therapy, then to punctal plugs and device therapy.
The following eye drops are currently covered by insurance in Japan and widely used.
Preservative-free artificial tears (e.g., Soft Santear): These form the foundation of treatment. Preservative-free formulations are preferred. Choose products that can be used while wearing contact lenses 7).
3% Diquafosol sodium ophthalmic solution (Diquas® / Diquas LX®) 6 times daily: A P2Y2 receptor agonist that promotes water and mucin secretion and oil layer spreading. Effective for both evaporative and aqueous-deficient dry eye. The Dry Eye Clinical Practice Guideline recommends its use (strong recommendation) 7). For use during contact lens wear, choose the preservative-free formulation (Diquas LX).
2% Rebamipide ophthalmic suspension UD (Mucosta® ophthalmic suspension UD) 4 times daily: Promotes mucin production and has anti-inflammatory effects. Particularly effective for aqueous-deficient dry eye (spot/dimple break). The Dry Eye Clinical Practice Guideline recommends its use (strong recommendation) 7). Single-use, preservative-free.
0.1% / 0.3% Sodium hyaluronate ophthalmic solution (Hyalein®) 6 times daily: Protects the corneal epithelium and retains moisture. During contact lens wear, avoid products containing preservatives 7).
The principles for changing contact lens materials in CLIDE are as follows.
| Pre-change Problem | Recommended Change |
|---|---|
| Smile mark SPK (SCL + dry eye) | Change to SiHy or HEMA with high water retention |
| 3 and 9 o’clock staining (HCL) | Consider changing to SCL. Re-evaluate fitting. |
| SEALs (stiff SiHy) | Change to soft SiHy or HEMA material. |
| Ring-shaped staining | Check and change incompatibility between SiHy and MPS used. |
| Severe SPK overall | Change to DD lens to eliminate care solution factors. |
If eye drops are insufficient, consider punctal plugs 7). However, in CLIDE where evaporative and aqueous-deficient types predominate, punctal plugs may cause tearing and blurred vision, so carefully assess indications.
If evaporative type predominates, warm compresses (5–10 minutes daily) and eyelid hygiene for MGD improve tear film stability 1). LipiFlow and IPL (intense pulsed light) are being studied for evaporative CLIDE with MGD background 1).
Oral omega-3 fatty acids have been reported to improve symptoms and BUT, but the evidence level is low and not covered by insurance, so they are an option as supplements 7).
If symptoms persist after stopping CL use, dry eye may have become chronic triggered by CL wear. Follow dry eye treatment guidelines and continue secretagogues such as diquafosol sodium or rebamipide 7). For severe and refractory cases, consider punctal plugs, and add warm compresses if MGD is present. Consider resuming CL use only after dry eye is well controlled.
CLs affect all layers of the tear film: the lipid layer, aqueous layer, and mucin layer. The core pathophysiology of dry eye is the “vicious cycle of tear film instability and corneal/conjunctival epithelial damage,” and CLs accelerate this cycle.
When a CL is present, the tear film is divided into the pre-lens tear film (in front of the CL) and the post-lens tear film (behind the CL). The pre-lens tear film is thinner than normal and evaporates more easily. The post-lens tear film has reduced tear diffusivity due to contact with the hydrophobic surface of the CL.
SiHy materials are prone to lipid deposits due to their hydrophobicity, and the lipids adhering to the surface destabilize the lipid layer of the tear film. While conventional HEMA lenses mainly had protein deposits, SiHy lenses produce deposits primarily composed of phospholipids and neutral lipids 2). Tear film instability caused by lipid deposits is one reason why dry eye symptoms in CL wearers have not improved even after the widespread adoption of SiHy lenses.
During CL wear, incomplete blinks (blinks where the eyelids do not close completely) increase. In incomplete blinks, the lower cornea is not covered by tears for a period, which coincides with the location of smile-mark punctate keratopathy. When blink rate further decreases during VDT work (from typically 16 times/min to 5–7 times/min), CLIDE markedly worsens due to the synergistic effect with CL wear 4). In vivo confocal microscopy studies by Jalbert et al. have also shown corneal epithelial damage and reduced nerve fiber density due to CL wear 14), suggesting that chronic CL wear affects corneal nerves, leading to decreased tear secretion and worsening of CLIDE.
Preservatives such as benzalkonium chloride (BAK) cause goblet cell damage and reduce the production of secretory mucin 5). Mucin deficiency leads to a wetting-deficiency type of tear breakup pattern (spot/dimple break), which worsens CLIDE. Switching to preservative-free care solutions and eye drops can help reduce mucin damage.
A vicious cycle is formed: tear film instability → epithelial damage → inflammatory cytokine production → goblet cell damage → mucin deficiency → tear film instability. CLs directly trigger the entry point of this cycle (tear film destabilization). Chronic stimulation of corneal sensory nerves leads to reduced sensation, further decreasing reflex tear secretion and accelerating the cycle.
Meibomian gland dysfunction (MGD) is a major exacerbating factor for CLIDE. When MGD is present, the tear lipid layer becomes thinner, leading to pronounced evaporative CLIDE. Daily warm compresses (5–10 minutes, approximately 42°C) and eyelid hygiene can improve MGD, stabilize the oil layer, and alleviate CLIDE symptoms 1).
Warm compresses and eyelid hygiene as treatment for MGD are the most basic and effective interventions to break the “vicious cycle” of CLIDE. In particular, for SiHy lens wearers with evaporative tear instability, it is desirable to prioritize MGD treatment before changing the CL material. For eyelid hygiene, use a dedicated eyelid cleanser (eyelid-specific cleaning product) and gently clean the meibomian gland openings 1–2 times a day.
Long-term CL wear reduces corneal sensation (hypoesthesia). Due to reduced sensation, CL wearers may not notice early symptoms of dry eye, and epithelial damage can progress unnoticed. As hypoesthesia advances, reflex tear secretion further decreases, leading to chronic CLIDE. Hypoesthesia is particularly pronounced in HCL wearers, but also occurs in SCL wearers with long-term use. To prevent chronic CLIDE, regular slit-lamp examination and tear film testing are important regardless of symptoms.
With appropriate CL material change, improved care, and eye drop treatment, most cases of CLIDE can be symptom-controlled. However, once CLIDE is established, background factors such as corneal hypoesthesia, MGD, and decreased goblet cell density may persist even after CL discontinuation, so careful evaluation is necessary before resuming CL wear.
Eye drop treatment is more likely to show symptom improvement when continued for at least 4 weeks, and improvement in findings (e.g., corneal staining) may require 2–4 months of continuous use 1). It is important to explain to patients that “effects may not appear immediately” to maintain adherence.
In managing CLIDE, controlling wearing time is a non-pharmacological intervention as important as drug therapy.
| Guideline for Wearing Time | Recommendations |
|---|---|
| Daily wearing time | Generally within 8–10 hours |
| Removal time before bedtime | Remove CL 2–3 hours before bedtime to allow tear film recovery |
| Wear during sleep | Absolutely prohibited (exacerbation of CLIDE + infection risk) |
| Regular check-ups | Ophthalmology visits 1–2 times per year are mandatory |
For patients who need to wear contact lenses for long periods (e.g., long-time VDT workers), it is effective to instruct them to take “hydration breaks” by removing the lenses and switching to glasses midway. Also recommend carrying preservative-free eye drops (e.g., Diquas LX, Hyalein preservative-free) for use.
In the management of CLIDE, patient education is fundamental to treatment. Provide specific guidance on the following points.
TFOS DEWS III (2025) identifies CL wear as a risk factor for dry eye and recommends changes in CL material, design, replacement frequency, and care solutions for the management of CLIDE 1). It also reports that lipid-containing artificial tears (lipomimetic eye drops) are effective in improving symptoms and corneal staining in CL wearers 1).
The TFOS Lifestyle Report states that there are approximately 300 million CL wearers worldwide, and that wearing CLs destabilizes the tear film and increases the risk of DED symptoms 3). Steele et al.’s review updates the epidemiology of CL-related infiltrative events, clearly positioning CLIDE as a risk factor for CIE 15). The combined effect of digital devices and CL wear is a major risk for CLIDE onset, especially in young adults 4).
With the widespread use of multifocal soft CLs and orthokeratology for myopia progression control, managing CLIDE in children and adolescents will become an important issue. Although Level I RCT evidence for multifocal CLs is accumulating, the evaluation of dry eye risk associated with long-term wear is still insufficient 6).
LipiFlow (vectored thermal pulsation therapy) and IPL (intense pulsed light) are being studied as treatment options for evaporative CLIDE associated with MGD 1). Since evaporation is a key mechanism of CLIDE, the combination of MGD treatment and CL fitting is expected to gain attention.
It has been suggested that ocular surface weakening and reduced tear protection due to CLIDE may predispose to Acanthamoeba keratitis (AK). Switching to DD lenses eliminates poor care and is reported to reduce AK risk by approximately 3.84 times compared to DW reusable lenses 8). In managing CLIDE, changing to DD lenses is also an effective strategy for preventing care solution-related complications.
When CLIDE becomes severe, the risk of CL-related non-infectious corneal infiltrative events (CIE) increases. CIE includes asymptomatic infiltrates (AI), CLARE, etc. 11), with an annual incidence of approximately 3–6 per 100 person-years 12). With EW of SiHy lenses, the annual CIE incidence reaches about 20 per 100 person-years 12), and CLIDE and CIE should be understood as a continuous disease spectrum.
Lens case contamination is also one of the exacerbating factors of CLIDE. Bacterial contamination is found in 30–80% of lens cases in use 13), and endotoxins derived from contaminating bacteria may be continuously exposed to the ocular surface, potentially worsening CLIDE.
In patients suspected of having CLIDE, according to the Infectious Keratitis Clinical Practice Guidelines (3rd edition), if the triad of hyperemia, discharge, and pain is present, infectious keratitis should be considered first, and corneal culture testing should be performed 9).
According to the definition of the TFOS International Workshop on Contact Lens Discomfort, contact lens discomfort is defined as “discomfort that in principle continuously worsens with contact lens wear” 10), and CLIDE is positioned as a major causative disease of this CL discomfort. In patients complaining of persistent CL discomfort, actively evaluating and treating CLIDE is important for improving the rate of continued lens wear.
