In medicine, our understanding and definition of disease processes continually evolve as technological advances uncover new insights. The eye is no exception, which brings us to our current discussion: How should we define ocular surface disease (OSD) vs. dry eye disease (DED)?

A history of terminology
Taking a historical perspective, the Latin term keratoconjunctivitis sicca was first coined in 1933 by Swedish ophthalmologist Henrik Sjögren.¹ He referred to DED specifically as the dry inflammation of the cornea and conjunctiva associated with Sjögren’s syndrome.¹

In 1950, Andrew de Roetth re-introduced the term keratoconjunctivitis sicca as “dry eye,” defining it as a reduction in the aqueous phase of the tear film.²

By 1995, the definition of DED once again changed to include both signs and symptoms, stating it as a disorder that “causes damage to the interpalpebral ocular surface and is associated with symptoms of ocular discomfort.”³

In 2007, the first Tear Film & Ocular Surface Society (TFOS) International Dry Eye Workshop (DEWS) updated the definition of DED to “a multifactorial disease of the tears and ocular surface that results in symptoms of discomfort, visual disturbance, and tear film instability, with potential damage to the ocular surface. It is accompanied by increased osmolarity of the tear film and inflammation of the ocular surface.”^4,5

In 2023, the TFOS’ Lifestyle Workshop Report stated that OSD “was deemed to include established diseases affecting any of the listed structures, as well as etiologically related perturbations and responses associated with these diseases.”⁶

The differences
Discussing OSD under the broad umbrella mentioned acknowledges the interconnectedness of DED and related conditions, such as limbal stem cell disease, neurotrophic keratitis, and meibomian gland dysfunction. This categorization allows us to address a wider range of issues, while using “DED” for more specific cases within that spectrum.

Additionally, the term “OSD” adds to the gravity and size of the overall problem. The TFOS DEWS I and DEWS II reports have laid the groundwork for this understanding.

Evolving distinctions
As we continue to explore the complex interactions within the ocular surface, precise language will enable us to better meet patient needs. The TFOS DEWS reports have progressively re-fined our understanding, and with DEWS III on the horizon, this approach will likely be further solidified.

Embracing these distinctions, which will, no doubt, continue to evolve, is essential for advancing both clinical practice and scientific inquiry in ocular surface health. And that is why this column is more than just “Dry Eye.” OM

References:

1. Sjögren, Henrik. “Zur kenntnis der keratoconjunctivitis sicca:(keratitis filiformis bei hypofunktion der tränendrüsen).” (1933): 1-151.

2. De Roetth A. Lacrimation in normal eyes. Arch Ophthalmol. 1953;49(2):185–189. doi: 10.1001/archopht.1953.00920020190008.

3. Lemp MA. Report of the National Eye Institute/Industry workshop on the Clinical Trials in Dry Eyes. CLAO J. 1995;21(4):221–232.

4. Dry Eye Workshop. The definition and classification of dry eye disease: report of the Definition and Classification Subcommittee of the International Dry Eye Workshop. Ocul Surf. 2007;5(2):75–92. doi: 10.1016/s1542-0124(12)70081-2.

5. Craig, JP., Nelson JD, Azar DT, et al. The TFOS DEWS II Report Executive Summary. The Ocular Surface. 2017;15(4):802-812.Craig, JP, Alves M, Wolffsohn JS,  et al.

6. TFOS Lifestyle Report Introduction: A Lifestyle Epidemic – Ocular Surface Disease. Ocul Surf.  2023;:28:304-309.  doi: 10.1016/j.jtos.2023.04.014.

Cecelia Koetting, OD, FAAO, is a clinical instructor at the University of Colorado School of Medicine. She is a fellow of the American Academy of Optometry, diplomate of the American Board of Optometry, an active American Optometric Association member, and she consults for multiple companies. Email her at Dr.CeceliaKoetting@gmail.com.