By Paul S. Koch, MD, Special to Ophthalmology Times
Warwick, RI—Clinicians today have a variety of diagnostic and therapeutic measures for their patients with dry eye.
At one time, the only available treatment was artificial tears—many of which contained the preservative, benzalkonium chloride, an agent that has been well documented as detrimental to ocular health.1
Diagnostic methods were also similarly lacking. In the past, clinicians were limited to fluorescein staining and Schirmer strips. Without a reliable diagnosis, a beneficial therapy could not be provided.
As a whole, diagnosing properly, following specific treatment plans, and providing excellent communication can keep patients happy and ensure the best ocular health.
When it comes to diagnosing dry eye, the first and most important tool remains patient history. Improved questionnaires better elicit what is happening with the ocular surface and provide an excellent starting point. Tear osmolarity should be determined next, along with an examination to discover any possible concurrent issues.
Though osmolarity has been difficult to determine in the past, the advent of devices (such as the TearLab Osmolarity System, TearLab Corp.) have made the process easier. Determining osmolarity is vital, as it will be higher in a number of dry eye etiologies. If tear concentration is normal, the problem will be fairly minor. With a high osmolarity, tears are too concentrated.
Classic dry eye (without meibomian gland disease) is a condition of high tear concentration. Eyes become irritated because what amounts to “scum on a pond” is sitting on the ocular surface. Patients may have trouble seeing because their tears are too thick, or their eyes may tear frequently in an effort to dilute the tear film. Normal concentration is 280 to 300. A concentration of 310 or higher requires intervention, at which point drop therapy tpically is started.
Plan A. When patients begin drop therapy, they are provided with a sample of two medications (Refresh, Allergan; Systane, Alcon Laboratories). They are directed to put Refresh in the right eye (R in the Right) and Systane in the left (S in the OS). Patients then report how their eyes feel, specifically if one eye feels better than the other. This indicates if one drop is working better than the other. If so, that therapy is continued.
Our clinic has now attempted treatment with two different drops, which meets the insurance requirement for the state of Rhode Island. If the patient returns still needing relief, the practice can move on to the next step without worrying about insurance issues—efficiently moving the patient through the process quickly.
Plan B. If topical therapy does not work, the next step is punctal occlusion. Plugs are a good option in any circumstance, as they are not episodic and work around the clock. Absorbable plugs (Comfortear Lacrisolve 180 Absorbable Punctum Plugs, Paragon BioTeck Inc.) are well tolerated by patients. There is no foreign body sensation, as they are inserted directly into the canaliculi. In addition, because the devices are not permanent, patients generally experience less trepidation.
Allergy or dry eye: Which is it?
Plan C. If drops and plugs are insufficient, an agent is attemped to stimulate gland production. Our office utilizes cyclosporine ophthalmic emulsion (Restasis, Allergan) or an oral agent containing omega fatty acids (HydroEye, Science Based Health). In Rhode Island, insurance companies frequently refuse cyclosporine due to the cost. When this occurs, or if patients object to a drop, then they wil be put on the oral agent. Tear concentration numbers are monitored just as IOP would be monitored. That information is shared with patients and treatment is adjusted as necessary.
Case study. A 72-year-old woman presented with a normal examination and excellent scans. However, in doing the lens calculation, one eye had an average K of 42 while the other eye had an average of 44. This was unusual, as the corneal curvatures are typically close in power. Topography verified this inconsistency.
Generally, two different lens powers would have been chosen and implanted. However, this patient also had a tear osmolarity in the 325 range. Instead of performing immediate surgery, it is first necessary to adjust the patient’s tear film. The punctum plugs were inserted and the patient returned 3 weeks later.
This time, both corneas measured 42 D. The eye that had measured 44 D had an unreliable reading caused by a thickened tear film. Had those results been used, the IOL power chosen would have been off by 2 D. Treating the tear film and repeating the preoperative measurements resulted in a greatly improved outcome.
Plugs can significantly assist in optimizing the ocular surface prior to surgery, especially for patients with a tear film concentration measuring 315 or higher. If preoperative measurements are off in a patient with dry eye already using drops, then plugs will be inserted immediately rather than trying other drops first. This stabilizes the cornea as quickly as possible. The patient can then return within a short period and achieve a much more accurate measurement.
One of the biggest issues with the term “dry eye” is that people do not understand its true meaning. Many dry eye patients have eyes that tear constantly, making the term appear contradictory. Explaining that the issue lies with a high tear concentration—specifically, the reason their eyes are tearing is to restore the eye’s natural balance of water and lipids by diluting the tears—is something patients understand and appreciate.
When a patient presents with dry eye symptoms, there are two ways to approach treatment. One is to perform the necessary tests, diagnose high tear concentration, and utilize a targeted treatment plan. The second approach involves giving the patient a handful of tear samples and hoping one works.
Years ago, that second option may have been optimal when there were fewer options available. This is no longer the case. Clinicians now have the tools required to diagnose and provide excellent therapy—arriving at better results more efficiently.
1. Baudoin C. Detrimental effect of preservatives in eyedrops: implications for the treatment of glaucoma. Acta Ophthalmologica. 2008;86:716-726.