It’s a simple task the optometrist does every day: refer a patient for cataract or refractive surgery. However, as our patients’ primary eye care provider, are we neglecting their ocular surface disease before surgery?
How many of my cataract referrals actually have Dry Eye Disease?
The prevalence of ocular surface disease among patients needing cataract surgery is much more common than previously thought. The PHACO study analyzed 136 patients scheduled to undergo cataract surgery and the results emphasize the need for proactive treatment of ocular surface disease. Although only 30% of patients reported symptoms, over 60% had an abnormal tear break-up time (TBUT), and 76% showed corneal staining with 50% of that staining presenting centrally.1
Translation: if you are only treating patients with complaints and not diagnosing objectively, you are missing a substantial amount of Dry Eye Disease.
TIP: Likely not all of the visual symptoms reported by your patients are from that cataract. Yes, photophobia and decreased vision are symptoms caused by a visually significant cataract; however, ocular surface disease can be another culprit. Is it only blurry vision, or also fluctuating vision? Make sure to probe with additional specific questions instead of just rely on your patient’s chief complaint. To facilitate this, utilize OSDI, the SPEED questionnaire, or the “Three Probe Way”:
- When you blink, does your vision clear up or get blurry?
- Do your eyes feel dry and/or like something is in them?
- Do your eyes ever get red?
These diagnostic surveys are simple tools for the optometrist to form his or her own protocol to initiate ocular surface management. For the OSDI, choose to treat based on severity of symptoms: mild, moderate, and severe. With the SPEED questionnaire, a score of six is a good place to start treating, and when using the “Three Probe Way,” two “yes” answers means start treatment.
What about the patients I’m referring for refractive surgery?
How many times do you hear your LASIK-desiring patients say they’re sick of their contact lenses? Oftentimes these patients have underlying dry eye disease or giant papillary conjunctivitis that is making them uncomfortable in their lenses. Treat this!
The end result is, one, you get them back into contact lenses comfortably, or two, you have ensured that the cornea is clear before refractive surgery. Here’s a scenario: a 26-year-old -2.00 contact lens wearer that you’ve seen for years presents to your office for her annual exam with no complaints other than she wants to check if she is a LASIK candidate. Topography looks good, prescription has been stable, and the patient has no dryness complaints. Do you stop there and send to the surgery center? No!
Schirmers test, tear break-up time (TBUT), and/or tear osmolarity are great tools you can include in your own dry eye protocol. You run a simple fluorescein test on this patient and see mild inferior corneal staining and a low Schirmers test. Treat this!
See her back in a few weeks after initiating treatment; then, if improved, refer. This 26-year-old contact lens wearer will be much more comfortable after refractive surgery thanks to your diligent care. Some patients will take longer than others to clear for surgery, and some patients will never be a candidate due to dry eye disease; but it is up to our careful testing and discernment.
Is treating ocular surface disease before surgery that important?
Absolutely! In order to select an accurate intraocular lens implant for cataract surgery, we must have correct data and measurements. This includes corneal topography, keratometry, and wavefront analysis. Corneal topography is an essential preoperative test to know how much corneal astigmatism is present. This is crucial in determining if the patient will need a toric IOL. Once the intraocular lens is removed, lenticular astigmatism is eliminated, thus corneal astigmatism is the only form of astigmatism that remains. If corneal topography is inaccurate, erroneous calculations will be made and the patient will end up unhappy. Moderate ocular surface disease renders the cornea irregular due to an unstable tear film, and thus, topography becomes imprecise.2,3
A severely dry patient with a spherical cornea may show false astigmatism due to an unstable tear film and be prepped for a toric IOL. This patient would end up needing an IOL exchange.
Take the following patient, who was referred for cataract surgery with significant uncontrolled dry eye disease. Figure 1 shows that his left eye corneal topography does not match with the keratometry provided by the IOL master. We see around 1.5 diopters of irregular astigmatism from the Pentacam topography, but 2.28 diopters from the IOL master at a different axis. The surgeon proceeded with a toric IOL implant, and although the lens implant was positioned exactly on axis postoperatively, the patient ended up with 1.50 diopters of cylinder due to inaccurate preoperative measurements. This patient was undoubtedly unhappy and an IOL exchange was performed with a spherical implant after initiating aggressive dry eye treatment.
Figure 1. Pentacam (top) with irregular astigmatism caused by ocular surface disease, compared with IOL Master (bottom left) with conflicting information. Dry eye disease can cause surface irregularity and fluctuations of tear film, thus rendering measurements unreliable.
For refractive surgery, we know from the PROWL-1 and -2 studies that dry eye symptoms can persist temporarily after LASIK: 23% of patients had mild dry eye, 2-3% of patients had moderate symptoms, and 1-3% had severe complaints postoperatively.4 There is also a loss of corneal sensation following LASIK,5 but usually by six months it improves to preoperative levels.6
Take a look at Figure 2: another example of how dry eye disease impacts the corneal surface, evident by the messy topography. See how irregular the cornea looks. Just by viewing, you can guess that this patient has ocular surface issues. Can you imagine the inaccuracies created by this measurement? You would not want to proceed with LASIK surgery before cleaning up this eye.
Figure 2. Irregular corneal topography
Big deal. What really happens if I don’t treat before referring?
One of the biggest setbacks for the patient is a delay in surgery. If there is significant ocular surface disease preoperatively and the patient gets to the surgery clinic without being treated, their surgery will be postponed until signs and/or measurements are improved. For patients expecting a premium IOL (toric, multifocal, or extended depth-of-focus), the preoperative corneal surface must be clear and regular. For patients with mild to moderate ocular surface disease, measurements will be improved after initiation of treatment and they can be cleared for a premium implant. Some patients with severe uncontrolled dryness, regardless of treatment, may not be candidates for premium surgery and may require a spherical implant. If we, as referring optometrists, introduce dry eye management before sending the patient for surgery, we are effectively reducing the surgeon’s chair time. Moreover, if explained thoroughly to the patient, they will recognize that we are the ones discovering a potential problem and preventing it from causing the patient future difficulties.
Treating dryness preoperatively will save you chair time postoperatively as well. We know that undergoing cataract surgery can temporarily induce dryness or exacerbate preexisting dryness,7 as can refractive surgery. Therefore, prophylactically treating even the “mild” patient may save the patient (and you!) a headache postoperatively.8
What can I do now?
Start working on your own Dry Eye Workup Protocol and implement it for all cataract and refractive surgery referrals. Anith Pillai’s article on how to start a dry eye practice is a great reference. Be sure to include objective testing and subjective surveys. Explain thoroughly to your patient why you are starting them on treatment. Now that you know the benefits of treating preoperatively, you will avoid post-op discomfort and dissatisfaction, and you can single-handedly improve surgery success rate!
References
- Trattler WB, Majmudar PA, Donnenfeld ED, Mcdonald M, Stonecipher KC, Goldberg D. The Prospective Health Assessment of Cataract Patients’ Ocular Surface (PHACO) study: the effect of dry eye. Clinical Ophthalmology. 2017; Volume 11:1423-1430. doi:10.2147/opth.s120159.
- Kent C. 37 Ways to Get Great Outcomes with Torics. Review of Ophthalmology. Published January 10, 2012.
- Lu N, Lin F, Huang Z, He Q, Han W. Changes of Corneal Wavefront Aberrations in Dry Eye Patients after Treatment with Artificial Lubricant Drops. Journal of Ophthalmology. Published 2016.
- Eydelman MDM. Symptoms and Satisfaction of Patients in the PROWL Studies. JAMA Ophthalmology. Published January 1, 2017.
- Shtein RM. Post-LASIK Dry Eye. Expert Rev Ophthalmology. October 2011; 6(5):575-582.
- Donnenfeld ED, Solomon K, Perry HD, et al. The effect of hinge position on corneal sensation and dry eye after LASIK. Ophthalmology. 2003; 110(5):1023-1029; discussion 1029-1030.
- Roberts CW, Elie ER. Dry eye symptoms following cataract surgery. Insight 2007;32(1):14-23.
- McCabe MDCF. How punctal occlusion improves multifocal IOL satisfaction. OphthalmologyTimes. Published May 1, 2013.
