Dry Eye (Keratoconjunctivitis Sicca, KCS)


The 2017 International Dry Eye Workshop (DEWS II) has provided the following definition: Dry eye is a multifactorial disease of the ocular surface characterised by a loss of homeostasis of the tear film, and accompanied by ocular symptoms, in which tear film instability and hyperosmolarity, ocular surface inflammation and damage, and neurosensory abnormalities play aetiological roles.

DED consists of two predominant and non-mutually exclusive categories; aqueous deficient dry eye (ADDE) and evaporative dry eye (EDE). Epidemiological and clinical evidence suggests that the majority of DED is evaporative in nature. Although ADDE can occur without EDE and vice versa, commonly the two categories co-exist.

ADDE and EDE can be sub-classified as follows:

1. Aqueous-deficient Dry Eye (ADDE)

  • Sjögren Syndrome Dry Eye (SSDE) I
  • Non-Sjögren Syndrome Dry Eye (NSDE)

2. Evaporative Dry Eye (EDE)

The core mechanism of DED is tear hyperosmolarity, which damages the ocular surface directly and initiates an inflammatory cascade leading to further ocular surface damage and loss of tear film homeostasis.

Predisposing factors

Wide variation in prevalence worldwide (6.5% to 52.4%); higher prevalence in post-menopausal women, people of Asian ethnicity and generally with increasing age.

Wide variation in prevalence by symptom compared to clinical diagnosis
Prevalence rises with age, between 2.0% and 10.5% per decade
Factors that aggravate symptoms:

  • vitamin A deficiency
  • noxious agents (cooking fumes, tobacco smoke)
  • increased evaporation of tears (air conditioning, central heating)
  • digital device use (reduced blink interval)
  • refractive surgery
  • contact lens wear
  • conjunctivitis medicamentosa secondary to long-term topical therapy

Symptoms of dry eye

  • ocular irritation
  • foreign body, gritty or burning sensation
  • presence of a stringy mucous discharge
  • blurring of vision from epithelial disruption or (transiently) from mucus strands
  • symptoms exacerbated by smoke, wind or heat; may worsen throughout the day
  • symptoms usually bilateral; may not be described as a feeling of dryness
  • associated symptoms of dry mouth, systemic disease (e.g. arthritis)

Signs of dry eye

  • reduced tear meniscus at inferior lid margin (following the instillation of fluorescein, normal meniscus is not less than 0.2 mm in height)
  • raised tear osmolarity (308 mOsm/l is the most sensitive threshold to distinguish normal from mild/moderate DED, while 315 mOsm/l is the most
    specific cut-off)
  • fluorescein break up time (FBUT) <10 sec
  • Schirmer test (without anaesthesia) ≤ 5mm in 5 min; may be helpful in the diagnosis of Sjögren’s Syndrome, but of limited value in non-Sjögren’s DED
  • punctate epithelial erosions in exposed area of cornea and bulbar conjunctiva (especially in inferior third of palpebral aperture). Stain with vital dye(s) as available. Various grading systems are available (e.g.Oxford staining score)
  • lid wiper epitheliopathy
  • increased mucus strands and other tear film débris
  • filaments (adherent comma-shaped mucus strands)
  • mucus plaques
  • Dellen
  • thinning and (very rarely) perforation
  • reduced corneal sensitivity

Differential diagnosis

Anterior blepharitis
Allergic and infective conjunctivitis
Eyelid abnormality or dysfunction leading to exposure (exposure keratopathy)
Nocturnal lagophthalmos (failure to close eyes at night)

Management by optometrist

Practitioners should recognise their limitations and where necessary seek further advice or refer the patient elsewhere

GRADE* Level of evidence and strength of recommendation always relates to the statement(s) immediately above

Non pharmacological:

Patient education regarding the condition

Modification of local environment

  • desiccating conditions and environmental pollutants
  • digital device use

(GRADE*: Level of evidence=low, Strength of recommendation=strong)

A 2019 Cochrane review concluded that long-chain omega-3 oral supplementation has a possible role in managing DED, although the evidence is uncertain and inconsistent.
(GRADE*: Level of evidence=low, Strength of recommendation=weak)

Tear conservation

  • diminish outflow – punctal plugs

(GRADE*: Level of evidence=moderate, Strength of recommendation=weak)

Lid hygiene for meibomian dysfunction (hot compresses, lid hygiene) (see Clinical Management Guideline on Blepharitis)
(GRADE*: Level of evidence=moderate, Strength of recommendation=strong)

Protection with therapeutic contact lenses
(GRADE*: Level of evidence=low, Strength of recommendation=weak)


Tear supplements (preferably unpreserved) for use during the day ± unmedicated ointment for use at bedtime
(Recent systematic review found no evidence to support the superiority of any particular tear supplement)
Liposomal sprays in evaporative dry eye
(GRADE*: Level of evidence=moderate, Strength of recommendation=strong)

Topical steroids (such as fluorometholone or loteprednol) may be considered for short-term use in some cases. The usual precautionary surveillance is required.
(GRADE*: Level of evidence=moderate, Strength of recommendation=weak)

Topical 0.1% ciclosporin A (CsA) cationic emulsion (Ikervis) is licensed in the UK for patients with DED with severe keratitis, which has not improved despite treatment with tear substitutes. However there is limited evidence of efficacy and safety of CsA preparations.
(GRADE*: Level of evidence=low, Strength of recommendation=weak)

NB Patients on long-term medication may develop sensitivity reactions which may be to active ingredients or to preservative systems (see Clinical Management Guideline on Conjunctivitis Medicamentosa). They should be switched to unpreserved preparations.

Management category

B2: alleviation or palliation; normally no referral.
B1: initial management followed by routine referral if adequate trial of topical treatment or punctal plugs fails to improve symptoms, or for secondary complications (vascularisation, corneal scaring, melt, or infection). If lid anatomy or function is abnormal, refer. If the condition is not idiopathic, for example if Sjögren’s syndrome or an unidentified systemic disease are suspected, refer.
A3: if SJS or OCP are suspected, refer urgently (within one week) to ophthalmologist.

Possible management by ophthalmologist

  • drug treatment for underlying disease (eg SJS, OCP)
  • autologous serum eye drops
  • electrolysis, cryotherapy
  • protection with therapeutic contact lenses of all types
  • permanent (surgical) occlusion of puncta
  • tarsorrhaphy (surgical or botulinum toxin)
  • transplantation of salivary gland/duct

Evidence base

*GRADE*: Grading of Recommendations Assessment, Development and Evaluation (www.gradeworkinggroup.org)

Sources of evidence

Akpek EK, Amescua G, Farid M, Garcia-Ferrer FJ, Lin A, Rhee MK, Varu DM, Musch DC, Dunn SP, Mah FS (American Academy of Ophthalmology Preferred Practice Pattern Cornea and External Disease Panel). Dry Eye Syndrome Preferred Practice Pattern. Ophthalmology. 2019;126(1):P286-P334

Bron AJ, de Paiva CS, Chauhan SK, Bonini S, Gabison EE, Jain S, Knop E, Markoulli M, Ogawa Y, Perez V, Uchino Y, Yokoi N, Zoukhri D, Sullivan DA TFOS DEWS II Pathophysiology Report. Ocul Surf. 2017;15(3):438-510. 

Courtin R, Pereira B, Naughton G, Chamoux A, Chiambaretta F, Lanhers C, Dutheil F. Prevalence of dry eye disease in visual display terminal workers: a systematic review and meta-analysis. BMJ Open. 2016;6(1):e009675

Craig JP, Nichols KK, Akpek EK, Caffery B, Dua HS, Joo C-K, Liu Z, Nelson JD, Nichols JJ, Tsubota K, Stapleton F. TFOS DEWS II Definition and Classification Report. Ocul Surf. 2017;15:276-83

Downie LE, Ng SM, Lindsley KB, Akpek EK Omega-3 and omega-6 polyunsaturated fatty acids for dry eye disease. Cochrane Database Syst Rev. 2019;12(12):CD011016

Dry Eye Assessment and Management Study Research Group. n-3 Fatty Acid Supplementation for the Treatment of Dry Eye Disease. N Engl J Med. 2018;378(18):1681-90

Ervin A-M, Law A, Pucker AD, Punctal occlusion for dry eye syndrome: summary of a Cochrane systematic review. Br J Ophthalmol. 2019;103:301-6

Jones L, Downie LE, Korb D, Benitez-del-Castillo JM, Dana R, Deng, SX, Dong PN, Geerling G, Yudi Hida R, Liu Y, Yul Seo K, Tauber J, Wakamatsu TH, Xu J, Wolffsohn JS, Craig JP. TFOS DEWS II Management and Therapy Report. Ocul Surf. 2017;15:575-628

de Paiva CS, Pflugfelder SC, Ng SM, Akpek EK. Topical cyclosporine A therapy for dry eye syndrome.
Cochrane Database Syst Rev. 2019;9:CD010051

Pucker AD, Ng SM, Nichols JJ. Over the counter (OTC) artificial tear drops for dry eye syndrome. Cochrane Database Syst Rev. 2016;2:CD009729

Wolffsohn JS, Arita R, Chalmers R, Djalilian A, Dogru M, Dumbleton K, Gupta PK, Karpecki P, Lazreg S, Pult H, Sullivan BD, Tomlinson A, Tong L, Villani E, Yoon KC, Jones L, Craig JP. TFOS DEWS II Diagnostic Methodology Report. Ocul Surf.2017;15:539-74


What is Dry Eye Disease?

Dry Eye Disease is also known by the medical term Keratoconjunctivitis Sicca, which means inflammation of the conjunctiva (the membrane overlying the white of the eye) and the cornea (the clear window of the eye) caused by dryness resulting from a deficiency or disorder of the tear film (the thin layer of tears covering the surface of the eye). It is a common condition affecting many people in the later decades of life. Most cases have no apparent cause but some are related to various inflammatory conditions, surgical treatment or as a side-effect of drug treatment. Some are caused by abnormalities of the eyelids or blinking, or by disorders of the meibomian (oil) glands of the eyelid margin.

Patients complain of irritation of the eyes, a feeling that there is something in the eye, a discharge from the eye, and sometimes blurred vision. They notice that their symptoms are worse in windy or dry conditions or when irritants such as smoke are in the air. When they are examined in the clinic they may be found to have reduced tear production or increased tear evaporation (sometimes due to lack of normal oil gland secretion). There may be damage to the surface of the eye produced by the increased saltiness of the tears.

How is Dry Eye Disease managed?

Tears can be supplemented with various drops and ointments. It is also possible to conserve natural tears by blocking the openings of the tear ducts, either temporarily with tiny plugs or permanently by surgery. Where the problem relates to a disorder of the oil glands, treatment is directed to the eyelids.

Dry eye (Keratoconjunctivitis Sicca) (KCS)
Version 15
Date of search 17.11.21
Date of revision 24.03.22
Date of publication 6.07.22
Date for review 16.11.23
© College of Optometrists 

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