A New Perspective on Dry Eye Classification: Proposal by the Asia Dry Eye Society

Abstract

The 2017 consensus report of the Asia Dry Eye Society (ADES) on the definition and diagnosis of dry eyes described dry eye disease as "Dry eye is a multifactorial disease characterized by unstable tear film causing a variety of symptoms and/or visual impairment, potentially accompanied by ocular surface damage." The report emphasized the instability of tear film and the importance of visual dysfunction in association with dry eyes, highlighting the importance of the evaluation of tear film stability. This report also discussed the concept of tear film-oriented therapy, which stemmed from the definition, and which is centered on provision of insufficient components in each tear film layer and ocular surface epithelium. The current ADES report proposes a simple classification of dry eyes based on the concept of tear film-oriented diagnosis and suggests that there are three types of dry eye: aqueous-deficient, decreased wettability, and increased evaporation. It is suggested that these three types respectively coincide with the problems of each layer: aqueous, membrane-associated mucins, and lipid/secretory mucin. Although each component cannot be quantitatively evaluated with the current technology, a practical diagnosis based on the patterns of fluorescein breakup is recommended. The Asia Dry Eye Society classification report suggests that for a practical use of the definition, diagnostic criteria and classification system should be integrated and be simple to use. The classification system proposed by ADES is a straightforward tool and simple to use, only through use of fluorescein, which is available even to non-dry eye specialists, and which is believed to contribute to an effective diagnosis and treatment of dry eyes.

FIG. 1.

Major etiological cause of dry eye in TFOS DEWS report in 2007. Reprinted from the ocular surface, Vol 5(2), the definition and classification of dry eye disease: Report of the definition and classification subcommittee of the International Dry Eye Workshop (2007), pages No. 75–92, copyright 2007, with permission from Elsevier.

FIG. 2.

Classification of dry eye disease in TFOS DEWS II. Reprinted from the ocular surface, Vol 15(3), Craig JP, Nichols KK, Akpek EK, et al. TFOS DEWS II definition and classification report, pages 276–283, copyright 2017, with permission from Elsevier.

FIG. 3.

Dry eye disease classification in Delphi approach (2006). Reprinted from cornea, Vol 25, Behrens A, Doyle JJ, Stern L, et al. Dysfunctional tear syndrome: A Delphi approach to treatment recommendations, pages 900–7, copyright 2006, with permission from Wolters Kluwer.

FIG. 4.

New dry eye disease classification by the Asia Dry Eye Society.

FIG. 5.

The concept of tear film-oriented therapy. *Diquafosol sodium may increase the function of the tear film lipid layer by promoting spreading of the lipid layer through lipid and tear fluid secretion. **Rebamipide may suppress the inflammation of the ocular surface in dry eye by its anti-inflammatory action. Figure provided by Dry Eye Society Japan.

FIG. 6.

Tear film-oriented therapy based on dry eye disease classification by ADES. ADES, Asia Dry Eye Society.

FIG. 7.

Classification of fluorescein breakup patterns.

FIG. 8.

Lacrimal gland hypofunction in visual display terminal (VDT) users and animal model. Upper Figures: Rat VDT user model causes alterations in lacrimal gland morphology. Electron microscopic analysis of acinar cells of normal and VDT rat model. Images showing expanded acinar cells accompanied by accumulated enlarged secretory vesicle in the cytoplasm, decreased endoplasmic reticulum. Scale bar = 10 micrometers. Lower Figures: Electron microscopic findings of the lacrimal gland acinus in human normal and VDT user. Homogeneous secretory vesicles in normal controls. Scale bar = 5 micrometers. High magnification view of secretory vesicles in the VDT user. Red arrows, arrowheads and asterisk show nuclei, secretory vesicles and ductal lumen, respectively. Figures from^, Nakamura et al. and Kamoi et al., respectively. These are open access articles distributed under the terms of the Creative Commons Attribution License.

FIG. 9.

Correlation between tear film breakup time and amount of glycocalyx at corneal surface. Glycocalyx at corneal surface was evaluated using a fluorescein-labeled wheat germ agglutinin (F-WGA) as a marker. Reprinted from current eye research, Vol 41, Fukui M, Yamada M, Akune Y, et al. Fluorophotometric analysis of the ocular surface glycocalyx in Soft Contact Lens Wearers, pages 9–14, copyright 2015, with permission from Elsevier.