Diagnosis of ocular surface disease crucial for surgery patients

ByKerry D. Solomon, MD

As the field of cataract and refractive surgery moves forward with new technologies such as aspheric intraocular lenses, toric lenses and multifocal lenses, ocular surface disease has begun to play a bigger role in determining results. These new technologies are far less effective with a challenged ocular surface, and thus physicians must be extremely vigilant in diagnosing and treating ocular surface disease among these patients. This article will discuss the diagnosis of various forms of ocular surface disease.

Dry eye symptoms and pathology

Ocular surface disease refers mainly to dry eye as well as anterior and posterior blepharitis. Beginning with dry eye, it is important to note that dry eye can not only result in itching and burning, but also impaired vision; cataract surgery patients often report some blurred or fluctuating vision, so keeping in mind that this could be caused by ocular surface disease can be useful.

The current thinking holds that there are a number of different triggers for dry eye. These can include environmental factors including air conditioning, medications, contact lens wear and surgery.

— Kerry D. Solomon, MD

In a healthy eye, normal tearing depends on a neuronal feedback loop. Secretomotor impulses are directed to the lacrimal glands, which produce tears to lubricate the ocular surface; this provides a neural stimulus from the ocular surface, which then feeds back to the brain from where the impulses originated. With dry eye, the lacrimal glands can secrete cytokines, which cause an inflamed ocular surface, thereby disrupting the neural input and preventing release of normal tears.^1,4

The current thinking holds that there are a number of different triggers for dry eye. These can include environmental factors including air conditioning, medications, contact lens wear and surgery. Chronic inflammatory conditions such as rheumatoid arthritis, lupus, Sjögren’s syndrome and graft vs. host disease can also cause dry eye. And finally, Meibomian gland disease can be a trigger for the condition. ^2,3

Risk factors and evaluation of dry eye

The risk factors for dry eye fall into three categories based on the consistency of the association. Some of the consistent risk factors include older age, female gender, certain medications such as antihistamines, connective tissue disease and radiation therapy. Some factors for which there is a reasonable suggestion of correlation with dry eye are Asian race, medications such as diuretics and betablockers, diabetes mellitus and ovarian dysfunction. Finally, there are factors that may be connected with dry eye but the association remains unclear at this point; these include cigarette smoking, Hispanic race, anticholinergic medications and oral contraceptives (Table 1). ⁴

Table 1

Table 1. Risk factors for dry eye
Table 1. Risk factors for dry eye.

Altinors DD, et al. Smoking associated with damage to the lipid layer of the ocular surface. Am J Ophthalmol. 2006 Jun;141(6): 1016-1021.

Schaumberg DA, Sullivan DA, Buring JE, Dana MR. Prevalence of dry eye syndrome among US women. Am J Ophthalmol. 2003 Aug;136(2): 318-326.

There are several methods for evaluation of dry eye. Schirmer’s testing, with and without anesthesia, is one method; with anesthesia the test can eliminate stimulated tearing, and without it can measure reflex tear secretion. It is not recommended, however, to base treatment on this test alone.

Slit-lamp evaluation allows for detailed examination of the ocular surface. One can evaluate the tear meniscus, and with fluorescein staining the corneal epithelial integrity can be assessed. Also, tear stability can be assessed using this stain and a tear breakup test; fluorescein tear breakup times of less than 10 seconds are considered to be abnormal. Rose Bengal or lissamine green staining is also useful in detecting areas of dried epithelium and for assessing conjunctival surface disease.⁵ Along with these methods, a detailed patient history and clear description of symptoms such as burning, stinging and fluctuating vision can provide a thorough diagnosis.

Anterior and posterior blepharitis

Blepharitis, or lid margin disease, is the most common and arguably the most important diagnosis presenting to ophthalmologists. In anterior blepharitis, inflammation is centered around the eyelash and the follicles, while in posterior disease the inflammation involves the meibomian gland orifices.

Symptoms of anterior blepharitis include morning crusting, foreign body sensation, recurrent hordeola or chalazia, loss of lashes and staphylococcal autoimmune disease (Table 2). Some of the sequelae associated with blepharitis are punctuate keratitis, phlyctenules, dry eyes and recurrent conjunctivitis. At the severe end of the sequelae spectrum, endophthalmitis is also related to blepharitis.

Table 2

Table 2. Signs and symptoms of anterior blepharitis
Table 2. Signs and symptoms of anterior blepharitis.

Anterior blepharitis is most commonly caused by a staphylococcal infection, whereas posterior blepharitis is related frequently to meibomian gland inspissation. Normal Meibomian gland secretions convert from unsaturated to saturated lipids; due to the disease process, lipids solidify at the temperature of the lids due to an increase in their melting point and clog the gland orifices. This leads to a loss of lipid in the tear film, resulting in an evaporative dry eye. The symptoms of posterior blepharitis include burning, foreign body sensation and other dry eye symptoms, as well as foam in the tear film, dilated meibomian gland orifices, chalazia and a thickened lid margin.⁶

Ocular surface diseases are extremely common and can severely compromise vision in cataract and refractive surgery patients if not diagnosed in a timely fashion. As technologies evolve vigilance in diagnosing and treating dry eye and blepharitis must progress accordingly.

References

Stern ME, Beuerman RW, Fox RI, et al. The pathology of dry eye: the interaction between the ocular surface and lacrimal glands. Cornea. 1998:17:584-589.
Shimazaki J, Goto E, Ono M, Shimmura S, Tsubota K. Meibomian gland dysfunction in patients with Sjögren syndrome. Ophthalmology. 1998 Aug;105(8):1485-1488.
Goto E, et al. Tear evaporation rates in Sjögren syndrome and non-Sjögren dry eye patients. Am J Ophthalmol. 2007 Jul;144(1):81-85
Nelson JD, Helms H, Fiscella R, et al. A new look at dry eye disease and its treatment. Adv Ther. 2000;17:84-93.
Lemp MA. Report of the National Eye Institute/Industry Workshop on Clinical Trials in Dry Eyes. CLAO J. 1995;21:221-232.
Jackson WB. Blepharitis: current strategies for diagnosis and management. Can J Ophthalmol. 2008;43:170-179.