CATARACT SURGERY is the most common surgical procedure performed worldwide (Wang, 2017), and the surgeons who perform it are no longer “just” cataract surgeons—they’re refractive surgeons, as patients expect accurate refractive outcomes and spectacle independence afterward. Today, surgeons can hit their refractive target at the very least within 0.5D 60% of the time and 1.0D 90% of the time, but this requires good biometry (Sheard, 2014).

Tear film instability, hallmarked by hyperosmolarity and a low tear breakup time (TBUT), along with corneal staining, results in the decreased repeatability of keratometry and axial length measurements (Hiraoka et al, 2022). Accurate pre-op measurements are essential for correct intraocular lens calculations.

In a study by Epitropoulous and colleagues (2015), patients who had a hyperosmolar tear film had a statistically significant calculated IOL power difference of more than 0.5D, the highest difference being 5.5D. The study found that a 1.0D error in pre-op keratometry resulted in 1.0D of post-op refractive error. This shows the importance of treating dry eye disease (DED) prior to surgery.

The Prospective Health Assessment of Cataract Patients’ Ocular Surface (PHACO) study demonstrated a high frequency of DED (close to 80%) in patients who present for cataract surgery, while a small percentage (only 22%) have a known previous diagnosis, and a few more than that (~30%) report at least occasional symptoms (Trattler et al, 2017). Not surprising, clinical signs and symptoms of DED don’t always correlate and it’s often undiagnosed.

Also, preexisting DED is a known risk factor for post-surgical dry eye symptoms and is a reason some patients are dissatisfied with their post-op results (Ishrat et al, 2019)—another good reason to screen for DED before surgery.

The first screening step is a dry eye questionnaire to determine whether additional testing should be done. Nevertheless, a high percentage of dry eye patients are asymptomatic, so point-of-care testing, such as osmolarity and MMP-9 testing, can be a tipoff if tear film instability and/or inflammation is present and can also help evaluate a patient’s response to treatment.

After any noninvasive ocular surface disease tests (meibography, topography, lipid layer thickness, aberrometry, noninvasive tear breakup time [NI-TBUT], and Schirmer’s) comes the clinical exam. It’s pertinent to “look, lift, pull, and push” on the lids according to the American Society of Cataract and Refractive Surgery preoperative algorithm, concluding with using vital dyes to look for corneal/conjunctival staining and performing a TBUT (Starr et al, 2019).

After the diagnosis is confirmed and baseline testing is performed, it’s time to inform the patient that surgery must be delayed until their dry eye is better controlled so their measurements will be more reliable; involve them in instituting a treatment plan. The goal is to reduce inflammation and restore ocular surface homeostasis using any combination of multiple therapeutic options, including topicals, orals, lifestyle changes, and/or office-based procedures. After treatment is initiated, the patient can be brought back several weeks later to repeat measurements and the screening process until biometry measurements are reliable and of a good quality, adjusting the treatment plan along the way until the ocular surface is optimized.

Taking time preoperatively to optimize the health of the ocular surface is critical to maximizing the refractive outcome of cataract and refractive surgery and to the patient’s post-op recovery and comfort. CLS

References

1. Wang W, Yan W, Müller A, He M. A global view on output and outcomes of cataract surgery with national indices of socioeconomic development. Invest Ophthalmol Vis Sci. 2017 Jul;58:3669-3676.
2. Sheard R. Optimizing biometry for best outcomes in cataract surgery. Eye (Lond). 2014 Feb;28:118-125.
3. Hiraoka T, Asano H, Ogami T, et al. Influence of dry eye disease on the measurement repeatability of corneal curvature radius and axial length in patients with cataract. J Clin Med. 2022 Jan 28;11:710.
4. 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 Aug;41:1672-1677.
5. Trattler WB, Majmudar PA, Donnenfeld ED, McDonald MB, Stonecipher KG, Goldberg DF. The prospective health assessment of cataract patients’ ocular surface (PHACO) study: the effect of dry eye. Clin Ophthalmol. 2017 Aug 7;11:1423-1430.
6. Ishrat S, Nema N, Chandravanshi SCL. Incidence and pattern of dry eye after cataract surgery. Saudi J Ophthalmol. 2019 Jan-Mar;33:34-40.
7. Starr CE, Gupta PK, Farid M, et al; ASCRS Cornea Clinical Committee. An algorithm for the preoperative diagnosis and treatment of ocular surface disorders. J Cataract Refract Surg. 2019 May;45:669-684.