Sore, red or gritty eyes are one of the most common reasons people see a clinician, and one of the most common things to be handed a bottle of drops for, with little more said. Sometimes the drops are the right answer. Often they are not, and the discomfort, and occasionally surface damage, could have been avoided.
The reason is that "dry eye" is not one condition. It is part of a wider group called ocular surface disease, which covers the tear film, the eyelid margins, and the front surface of the eye. Treating every sore eye with the same drops is a bit like giving the same painkiller for every kind of headache.
What "Ocular Surface Disease" Actually Means
Modern expert guidance describes dry eye as a condition where the tear film loses its balance. The tears become unstable, more concentrated and salty, the eye surface becomes inflamed, and the nerves can become more sensitive. This is why some people feel very uncomfortable even when the eye looks only mildly affected.
The tear film has three thin layers working together: an oily layer from eyelid glands that stops tears evaporating, a watery layer from the tear glands, and a mucus layer that helps tears spread evenly. A problem in any one of these causes a different type of dry eye, and the treatments are not the same.
Most people who think they have dry eye actually have evaporative dry eye, caused by eyelid oil glands that are not working properly, rather than eyes that simply do not make enough tears.
The two main types, along with a few related conditions, are summarised below.
The common link between these conditions is inflammation. Even when the problem starts with something mechanical, such as blocked oil glands, the inflammation that follows can keep symptoms going. That is why treating inflammation is often important in moderate to severe dry eye disease, alongside lubrication.
Why a Thorough Assessment Is Worth It
Standard appointments for sore eyes are often short, and the equipment to look properly at the tear film and glands is not available everywhere. A fuller assessment can, in one visit, map the cornea, image the oil glands, scan the surface and measure the tears, building a clearer picture of what is actually going wrong rather than treating by guesswork.
This matters even more for anyone heading towards cataract surgery or lens-replacement surgery. An unstable or inflamed surface can throw off the measurements used to choose the lens implant, which makes the final vision less predictable. Settling the surface first improves the accuracy of those measurements. For that reason, a good pre-surgery plan treats the surface before the measurements are taken, not afterwards.
What Recovery Really Looks Like
Ocular surface disease does not follow the usual "take a course and it clears up" pattern. For most people the realistic goal is good control rather than a permanent cure, because it tends to be a long-term, up-and-down condition. Anti-inflammatory drops in particular need a fair trial, usually eight to twelve weeks, before judging whether they are helping. This is normal and not a sign of failure. With the right plan, most people can get their symptoms to a level that no longer interferes with daily life.
Questions Worth Asking Any Clinic
Whoever you see, a few questions help you judge whether an assessment is thorough. These are reasonable to ask of any provider before booking:
- Will the surface of my eye be checked and settled before any measurements for surgery are taken?
- Is corneal topography (a scan of the cornea) done routinely, so conditions like keratoconus are picked up early?
- Will the consultant who assesses me also plan and carry out my treatment or surgery, so there is continuity of care?
- If the first treatment does not work, what is the plan for the next step?
A Practical Checklist Before Your Appointment
If you are arranging an assessment for sore eyes, cataract surgery, or a related procedure, the following preparation helps the clinician get the fullest picture:
- List all your current medicines. Some common ones, including antihistamines, certain antidepressants and water tablets, can reduce tear production. Bring any eye drops you are using too.
- Note when your symptoms are worst. Worse in the morning can point to overnight or eyelid problems; worse by the evening can point to evaporation or screen-related strain.
- If you wear contact lenses, leave them out before any dry eye assessment or pre-surgery measurements, as lenses change the shape of the cornea and the tear film. As a guide, soft lenses should be left out for at least one to two weeks, and rigid (gas-permeable) lenses for longer; your clinic can advise on the exact timing.
- Bring previous optician reports, corneal scans, or hospital letters, so changes over time can be seen.
- Ask, when booking, whether the appointment includes a slit-lamp examination, corneal topography and an assessment of the eyelid oil glands.
References
- Tear Film and Ocular Surface Society. TFOS DEWS III Report. Am J Ophthalmol; 2025.
- Craig JP, Nichols KK, Akpek EK, et al. TFOS DEWS II Definition and Classification Report. Ocul Surf. 2017;15(3):276–283.
- Nelson JD, Shimazaki J, Benitez-del-Castillo JM, et al. The international workshop on meibomian gland dysfunction: report of the definition and classification subcommittee. Invest Ophthalmol Vis Sci. 2011;52(4):1930–1937.
- Lemp MA, Crews LA, Bron AJ, Foulks GN, Sullivan BD. Distribution of aqueous-deficient and evaporative dry eye in a clinic-based patient cohort. Cornea. 2012;31(5):472–478.
- Baudouin C, Messmer EM, Aragona P, et al. Revisiting the vicious circle of dry eye disease. Br J Ophthalmol. 2016;100(3):300–306.
- Sall K, Stevenson OD, Mundorf TK, Reis BL. Two multicenter, randomized studies of the efficacy and safety of ciclosporin ophthalmic emulsion in moderate to severe dry eye disease. Ophthalmology. 2000;107(4):631–639.
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- Dell SJ. Intense pulsed light for the treatment of meibomian gland dysfunction. Clin Ophthalmol. 2017;11:1167–1173.
- Pan Q, Angelina A, Marrone M, Stark WJ, Akpek EK. Autologous serum eye drops for dry eye. Cochrane Database Syst Rev. 2017;(2):CD009327.
- Epitropoulos AT, Matossian C, Berdy GJ, Malhotra RP, Potvin R. Effect of tear osmolarity on repeatability of keratometry for cataract surgery planning. J Cataract Refract Surg. 2015;41(8):1672–1677.
- Gomes JAP, Tan D, Rapuano CJ, et al. Global consensus on keratoconus and ectatic diseases. Cornea. 2015;34(4):359–369.
