Data from the Swedish Cataract Registry showed that patients with corneal guttae benefited from cataract surgery but had poorer visual acuity and self-reported visual function than patients without guttae.1 As corneal surgeons, we are concerned about the recommendation to wait at least 3 weeks after cataract surgery to decide on corneal transplantation.
First, it is important to differentiate visual impairment caused by edema versus guttae alone. The slower visual recovery noted in patients with guttae1 was caused by secondary edema from the acute trauma of cataract surgery on corneal endothelial cells functionally compromised by guttae.2
The effect of guttae alone on vision traditionally has been underestimated. When the only treatment for Fuchs dystrophy was penetrating keratoplasty (PKP), which had unpredictable refractive results and variable visual recovery that could take years, patients were advised to postpone surgery until advanced corneal edema severely impaired vision.
Today, we can selectively replace dysfunctional endothelium and guttae with Descemet membrane endothelial keratoplasty (DMEK). Patients often realize visual improvement within a few days and can have the fellow eye treated within 1 to 2 weeks.2 We have performed DMEK in patients with no clinically discernible edema, only guttae, who have a preoperative corrected distance visual acuity (CDVA) of 20/20 or better in a dark room using high-contrast letters. Afterward, when they compare the vision in the treated eye with that in the untreated eye, they frequently ask to have the “better” fellow eye treated as soon as possible to eliminate the glare, halos, and poor contrast caused by the guttae. This is similar to cataract patients who have good vision measured with an eye chart in a dark room but experience disabling phenomena such as glare and halos caused by posterior subcapsular cataracts. We do not wait for the cataracts to get “ripe” now that we have intraocular lenses (IOLs). Likewise, we should not wait for corneas to get “ripe” with edema; instead, we should go ahead and treat the visual disability caused by the guttae alone.
A simple analogy to patients with cataracts and guttae is a window with 1 side covered with brown dust and the other covered with raindrops. We can clean off the dust and the view through the window will improve, but the view will still not be great because of the raindrops on the other side. If we use cold water to wipe off the dust, we might get fog on the other side as well as the raindrops; the fog is comparable to early postoperative edema. If we wipe off the raindrops, which distort the view similar to guttae, the view through the window finally clears.
We should think of eyes with guttae as we do windshields. We probably have all driven with a few raindrops on the windshield. The threshold to turn on the windshield wipers varies with the individual, the density of raindrops, the driving conditions, and the occasional fogging of the window. We have to assess how well patients can see through the window (cornea), the effect when driving at night with oncoming headlights, and how well can they see detail well enough to, for example, read road signs or see someone step in front of the car. We often find that patients do not fully appreciate the disability of guttae because it progresses so gradually. Asking the spouse whether they are comfortable riding with the patient driving at night often provides a better indication of the visual disability.
The benefit-to-risk ratio is so much better with DMEK or with Descemet stripping only than it was with PKP3,4; thus, whether to treat the guttae should be considered before cataract surgery—not after. First, patients frequently prefer to combine cataract surgery with DMEK or Descemet stripping only rather than have separate surgeries. Second, guttae reduce the accuracy of biometry.1 Therefore, for patients who desire a premium IOL or a very accurate refractive result, one should consider treating dense guttae before performing cataract surgery.5
Guttae, like rain drops, increase intraocular light scatter, decrease contrast sensitivity, and decrease visual acuity. Let us not underestimate the importance of keeping the window clear for our patients with these drops on their corneas.
1. Viberg A, Liv P, Behndig A, Lundström M, Byström B. The impact of corneal guttata on the results of cataract surgery. J Cataract Refract Surg 2019;45:803-809.
2. Kocaba V, Katikireddy KR, Gipson I, Price MO, Price FW, Jurkunas UV. Association of the gutta-induced microenvironment with corneal endothelial cell behavior and demise in Fuchs endothelial corneal dystrophy. JAMA Ophthalmol 2018;136:886-892.
3. McKee Y, Price MO, Gunderson L, Price FW Jr. Rapid sequential endothelial keratoplasty with and without combined cataract extraction. J Cataract Refract Surg 2013;39:1372-1376.
4. Iovieno A, Neri A, Soldani AM, Adani C, Fontana L. Descemetorhexis without graft placement for the treatment of Fuchs endothelial dystrophy: preliminary results and review of the literature. Cornea 2017;36:637-641.
5. Schoenberg ED, Price FW Jr, Miller J, McKee Y, Price MO. Refractive outcomes of Descemet membrane endothelial keratoplasty triple procedures (combined with cataract surgery). J Cataract Refract Surg 2015;41:1182-1189.
Neither author has a financial or proprietary interest in any material or method mentioned.