Cases of concurrent keratoconus and Fuchs endothelial dystrophy have been reported in the literature.1 Traditionally, penetrating keratoplasty has been the treatment choice.1 Nevertheless, both keratoconus and Fuchs endothelial dystrophy have been treated by less invasive procedures in recent years. In keratoconic eyes, intrastromal corneal ring segments (ICRS) implantation promotes corneal flattening and has significant advantages, such as reversibility,2 preservation of the central cornea, and much faster visual rehabilitation postoperatively.3 Concerning Fuchs endothelial dystrophy, Descemet membrane endothelial keratoplasty (DMEK) offers fast postoperative recovery, optimal visual results, and a low rejection rate.4
We describe two cases of coexisting Fuchs endothelial dystrophy and keratoconus treated with ICRS implantation and DMEK, in a two-stage procedure.
A 40-year-old man with coexisting keratoconus and Fuchs endothelial dystrophy presented with corrected distance visual acuity (CDVA) in the left eye of 20/100. Corneal guttae were evident. Femtosecond laser–assisted (150-KHz IntraLase FS laser; Abbott Medical Optics, Inc) implantation of two ICRS (Keraring IS-5, 160°/250 µm and 160°/200 µm; Mediphacos) was uneventful. The implantation depth was set to 75% of the lowest pachymetry point within the annular implantation zone (5 to 6 mm, Scheimpflug tomography pachymetric map). Twelve weeks after the procedure, topographic indices markedly improved and corneal edema was still observed (Figure 1A). DMEK was then performed, as previously described (Figure 1B).5 On the seventh day, a fixed dilated pupil was observed with normal intraocular pressure. Six months after the second procedure, the graft was completely attached, the cornea showed no edema, and CDVA reached 20/30. After DMEK, corneal astigmatism improved slightly, and the maximum keratometry value worsened to 1.00 diopter (D). The photophobia caused by Urrets-Zavalía syndrome was a major patient complaint and was successfully addressed with a colored contact lens fitting (artificial pupil contact lens).
(A) Corneal guttae and edema after the first day of intrastromal corneal ring segments (ICRS) implantation and (B) immediately after Descemet membrane endothelial keratoplasty (DMEK) (case 1). (C) Clinical aspect after DMEK and ICRS implantation (case 2). (D) Anterior segment optical coherence tomography shows a single segment implanted at 298 µm and no identifiable DMEK graft (case 2). B and C: white arrowheads show the borders of the endothelial graft and hollow arrowheads show the limits of the peripheral edge of the ICRS. (Photographs taken by Pedro Bertino [A and B] and Gustavo Novais [C]).
A 47-year-old woman with coexisting keratoconus and Fuchs endothelial dystrophy presented with CDVA in the left eye of 20/60. Corneal guttae were biomicroscopically seen. DMEK was performed uneventfully. After DMEK, corneal astigmatism remained stable and the maximum keratometry value worsened to 3.50 D. After 12 months, the patient underwent uneventful ICRS implantation (Keraring IS-5, single segment 160º/200 µm; Mediphacos). Six months after the second procedure, the CDVA was 20/25, there was no corneal edema (Figure 1C), and the graft remained attached (Figure 1D).
For both cases, preoperative and postoperative data are summarized in Table 1.
Preoperative and Postoperative Data
Coexisting keratoconus and Fuchs endothelial dystrophy might be an underestimated association. Corneal edema in Fuchs endothelial dystrophy might be masked by the corneal thinning in keratoconus, and the expected corneal thinning in keratoconus could be thickened as a consequence of the edema caused by Fuchs endothelial dystrophy.1 In accordance, our second case showed falsely normal pachymetry results preoperatively, with a deturgescence of 116 µm after endothelial transplantation.
In case 1, we believed the steepening of the anterior corneal curvature played a more important role in lowering visual acuity than the initial endothelial dysfunction. Therefore, we preferred to perform ICRS implantation first, which reduced corneal astigmatism by 2.90 D and improved CDVA from 20/100 to 20/60, even in the presence of mild corneal edema. Nevertheless, the effects of ICRS implantation in edematous corneas have not been studied to date.
DMEK provides rapid restoration of endothelial function, excellent visual outcomes, and lower rejection rates. Thus, it has become the gold standard option for treating endothelial dysfunction.4
In 2014, Vira et al6 published a case series of 6 eyes with coexisting keratoconus and Fuchs endothelial dystrophy treated with Descemet stripping endothelial keratoplasty (DSEK). With stable topographic measurements of less than 53.00 D, all cases except one had visual improvement after DSEK. These were the first published cases of coexisting keratoconus and Fuchs endothelial dystrophy to be addressed by endothelial keratoplasty.
DMEK was uneventful in both of our cases. However, the presence of the two corneal segments in case 1 increased the difficulty in unfolding and centering the graft. Therefore, it might be preferable to perform the endothelial procedure first, a choice we made in our second case. Additionally, our second case had a much lower anterior curvature, suggesting the endothelial dysfunction played a more important role in visual impairment.
Another reason for avoiding the sequence of ICRS implantation and then DMEK is related to the possible miscalculation of the implantation depth in an edematous cornea. Pachymetric readings within the annular implantation zone may be inaccurate and lead to superficial implantation, which is associated with increased risk of segment extrusion in the long term. The use of corneal allogenic intrastromal ring segments may be an interesting alternative in such a scenario because superficial implantation and extrusion are not potential complications.7
It is noteworthy that in both cases maximum keratometry values increased after DMEK. A possible explanation is a false curvature measurement, taken preoperatively in edematous corneas. Once the endothelial function was restored by DMEK, the real keratoconic curvature appeared. Indeed, because topographic readings in edematous corneas may be inaccurate, this can be considered one more reason to advocate for DMEK before ICRS.
Urrets-Zavalía syndrome has been reported following lamellar procedures such as DSEK, Descemet stripping automated endothelial keratoplasty (DSAEK), or deep anterior lamellar keratoplasty.8 In 2012, Anwar et al8 reported a case series of 7 eyes with pupil abnormalities after DSAEK. Urrets-Zavalía syndrome has also been reported after DMEK.9
Although the origin of Urrets-Zavalía syndrome is still uncertain,10 in our cases we were able to identify three contributing factors for its development. The first is related to keratoconus because a higher rate of occurrence has been documented in keratoconic eyes. The second is related to perioperative intraocular pressure fluctuations due to the presence of an air bubble in the anterior chamber. Pupillary block or postoperative raised intraocular pressure have both been suggested as possible risk factors for Urrets-Zavalía syndrome.10 The last possible factor is related to incomplete removal of viscoelastic, which has also been associated with Urrets-Zavalía syndrome.
Low vision resulting from coexisting Fuchs endothelial dystrophy and keratoconus might be addressed more selectively with posterior lamellar keratoplasty and ICRS implantation. Urrets-Zavalía syndrome must be considered a possible complication after DMEK, especially in patients with keratoconus. To the best of our knowledge, these are the first reports of DMEK associated with ICRS for the treatment of coexisting keratoconus and Fuchs endothelial dystrophy.
- Jurkunas U, Azar DT. Potential complications of ocular surgery in patients with coexistent keratoconus and Fuchs' endothelial dystrophy. Ophthalmology. 2006;113(12):2187–2197. doi:10.1016/j.ophtha.2006.06.036 [CrossRef]
- Asbell PA, Uçakhan OO, Abbott RL, et al. Intrastomal corneal ring segments: reversibility of refractive effect. J Refract Surg. 2001;17(1):25–31.
- Coskunseven E, Kymionis GD, Tsiklis NS, et al. One-year results of intrastromal corneal ring segment implantation (KeraRing) using femtosecond laser in patients with keratoconus. Am J Ophthalmol. 2008;145(5):775–779. doi:10.1016/j.ajo.2007.12.022 [CrossRef]
- Price MO, Giebel AW, Fairchild KM, Price FW Jr, . Descemet's membrane endothelial keratoplasty: prospective multicenter study of visual and refractive outcomes and endothelial survival. Ophthalmology. 2009;116(12):2361–2368. doi:10.1016/j.ophtha.2009.07.010 [CrossRef]
- Kruse FE, Laaser K, Cursiefen C, et al. A stepwise approach to donor preparation and insertion increases safety and outcome of Descemet membrane endothelial keratoplasty. Cornea. 2011;30(5):580–587. doi:10.1097/ICO.0b013e3182000e2e [CrossRef]
- Vira S, Abugo U, Shih CY, et al. Descemet stripping endothelial keratoplasty for the treatment of combined Fuchs corneal endothelial dystrophy and keratoconus. Cornea. 2014;33(1):1–5. doi:10.1097/ICO.0b013e3182a7389c [CrossRef]
- Jacob S, Patel SR, Agarwal A, Ramalingam A, Saijimol AI, Raj JM. Corneal allogenic intrastromal ring segments (CAIRS) combined with corneal cross-linking for keratoconus. J Refract Surg. 2018;34(5):296–303. doi:10.3928/1081597X-20180223-01 [CrossRef]
- Anwar DS, Chu CY, Prasher P, Bowman RW, Mootha VV. Features of Urrets-Zavalia syndrome after Descemet stripping automated endothelial keratoplasty. Cornea. 2012;31(11):1330–1334. doi:10.1097/ICO.0b013e318259ca15 [CrossRef]
- Holtmann C, Spaniol K, Geerling G. Urrets-Zavalia syndrome after Descemet membrane endothelial keratoplasty. Eur J Ophthalmol. 2015;25(5):e75–e77. doi:10.5301/ejo.5000597 [CrossRef]
- Davies PD, Ruben M. The paretic pupil: its incidence and aetiology after keratoplasty for keratoconus. Br J Ophthalmol. 1975;59(4):223–228. doi:10.1136/bjo.59.4.223 [CrossRef]
Preoperative and Postoperative Data
|Parameter||Preoperative||Postoperative, 1st Procedurea||Postoperative, 2nd Procedureb|
| Case 1||20/100||20/60||20/30|
| Case 2||20/60||20/60||20/25|
|Manifest refraction, D|
| Case 1||Plano −4.00 @70º||+2.00 −3.00 @20º||+4.00 −1.50 @10º|
| Case 2||+2.25 −3.00 @105º||+1.75 −3.00 @115º||+1.25 −1.00 @145º|
|Topographic astigmatism, D|
| Case 1||5.30||3.40||2.40|
| Case 2||3.30||3.20||1.80|
|Maximum keratometry, D|
| Case 1||52.30||45.50||46.50|
| Case 2||45.50||49.00||47.90|
|Thinnest point, µm|
| Case 1||603||612||487|
| Case 2||524||408||411|
|Endothelial cell count, cells/mm2|
| Case 1||Unmeasurable||Unmeasurable||1,054|
| Case 2||Unmeasurable||1,160||1,095|