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[OCT Article] Case Report: Bullous Keratopathy

Through this case, we aim to emphasize the importance of early detection, vigilant monitoring, and personalized treatment for patients with a family history of glaucoma.
[OCT Article] Case Report: Bullous Keratopathy Image

This article was originally published in a sponsored newsletter in Optometric Management called "OCT Insights." Original article can be found here: https://optometricmanagement.com/issues/2024/september/case-report-bullous-keratopathy/

AL is a 55-year-old marine mammal biologist. He spends long days aboard vessels in far, off-the-grid locations for months at a time. Vision is critical to him because he spends most of his time photographing animals at sea. He found our practice online after doing significant research on contact lens specialists. He flies in for visits.

AL was diagnosed with iridocorneal endothelial (ICE) syndrome OS in 2012. He has tried multiple soft toric lenses without visual success. His entering visual acuity with glasses was 20/20 OD, 20/50-2 OS, 20/20 OU.

His habitual glasses prescription was:
-0.50-2.75x93 add +2.25
-3.75-1.50x27 add +2.25

Glasses refraction was found to be:
-0.25-2.75x85 add +2.00, 20/20 OD
-2.25-2.25x55 add +2.00, 20/30 OS

Finally, topography showed irregular mires OS with sim Ks of 42.50/43.75 (Figure 1).

Figure 1. Axial topographical map of the left eye. Irregular astigmatism was present in the left eye.

Because of his work demands and his interest in the best lens he could find, he chose to move forward with impression-based lenses. An impression was taken, and a trial lens was inserted to determine power. The fellow eye was fit with a soft toric lens.

At dispense, AL’s vision was 20/20+2 OS. The anterior segment OCTs are shown below (Figures 2 through 6). We imaged scleral prosthetic lenses centrally and in four principal meridians at the haptics to ensure an optimal fit.

Figure 2. Central vault was measured using calipers to assess the scleral prosthetic and shows 329u of vault over the central cornea here.
Figure 3. Inspection of the haptic nasally OS. We examined to ensure that the lens did not contact the limbus and that the haptic aligned with the sclera. Although the limbus is undefined, even by ophthalmic pathologists, we assume that where the cornea becomes more opaque in a wedge-shaped line is the start of the limbal zone (red arrow).
Figure 4. Inspection of the haptic temporally OS.
Figure 5. Inspection of the haptic superiorly OS.
Figure 6. Inspection of the haptic inferiorly OS.

This was deemed to be a perfect fit, and the patient was taught application, removal and care of the lens. The lens was dispensed, and the patient was scheduled for a two-week follow-up visit.

At the two-week visit, we noted that the limbal zone was tight (Figure 7), either due to forceful insertion (which creates a suction effect and pulls the lens onto the limbus) or standard settling of a prosthetic with spongy conjunctival tissue. We opted to educate the patient about gentle insertion technique and increased the optical zone diameter to allow for greater limbal clearance.

Figure 7. Image of haptic at the two-week visit, where it was noted that there was insufficient limbal clearance (arrow).

Lenses were dispensed with a larger optical zone diameter to preserve their overall diameter and to allow for greater limbal clearance nasally and temporally—where the cornea is widest after settling onto the eye (Figure 8).

Figure 8. Lens designed with increased limbal clearance (arrow).

The patient enjoyed an excellent visual result for the next two months, until he returned to the practice with a complaint of eye pain when removing his lenses. While the lenses were inserted, his comfort was perfectly fine. Visual acuity had dropped to 20/30+2 OS. Biomicroscopic evaluation showed mild corneal edema and epithelial bullae (Figure 9).

Figure 9. Image of epithelial bullae elegantly masked within the post-lens tear reservoir of a scleral prosthetic.

Discussion and Plan

Iridocorneal endothelial syndrome (ICE) is characterized by migration of corneal endothelial cells into the anterior chamber, resulting in atrophy of the iris, secondary glaucoma and corneal edema.1 It can result in bullous keratopathy, as we see in this case. Soft contact lenses have provided therapeutic benefit when combined with topical hypertonic drops.2

There are currently no papers in the literature that provide guidance on using scleral lenses with ICE syndrome. Without such guidance, practitioners must have a discussion with patients about risks and benefits. A patient who has serious visual demands may be willing to take the theoretical chance of worsening corneal edema.

That said, there are some guidelines that we can follow. We can fit scleral lenses and prosthetics to maximize oxygen transmission. For example, Giasson et al described the loss of corneal oxygenation between a 400 µm vault and 200 µm vault to be 30%.3 We can also ensure maximum oxygen transmission by choosing GP materials with maximum Dk.4

There is also a wonderful case series on the topic of transient epithelial bullae in patients wearing scleral lenses by Veronica Isozaki and Gloria Chiu.5 This paper cites the potential for increased risk of epithelial defects, infections and other complications.

In AL’s case, we prescribed a hypertonic to be used as an adjunct to filling the bowl of the prosthetic with saline. We re-ordered a lens with decreased vault and changed the material to one with a Dk of 180. We also discussed limiting the wear time to the minimum that he needed to perform his job tasks and using the hypertonic drop when he is not wearing his scleral lens.

At the time of this writing, two months after the initial fit, the patient has not returned with complaints or complications.

Reference(s):

  1. Das S, Tur K, Tripathy K. Iridocorneal endothelial syndrome. StatPearls [Internet]. Updated August 25, 2023. Accessed September 5, 2024. https://www.ncbi.nlm.nih.gov/books/NBK594227/
  2. Beganovic AP, Vodencarevic AN, Halilbasic M, Medjedovic A. Iridocorneal endothelial syndrome: case report of essential progressive iris atrophy. Med Arch. 2022 Jun;76(3):224-228. doi:10.5455/medarh.2022.76.224-2285
  3. Giasson CJ, Morency J, Melillo M, Michaud L. Oxygen tension beneath scleral lenses of different clearances. Invest Ophthalmol Visual Sci. 2017 Apr;94(4):466-475. doi: 10.1097/OPX.0000000000001038
  4. Michaud L, van der Worp E, Brazeau D, Warde R, Giasson CJ. Predicting estimates of oxygen transmissibility for scleral lenses. Cont Lens Anterior Eye. 2012 Dec;35(6):266-271. doi: 10.1016/j.clae.2012.07.004
  5. Isozaki VL, Chiu GB. Transient corneal epithelial bullae associated with large diameter scleral lens wear: a case series. Cont Lens Anterior Eye. 2018 Oct;41(5):463-468. doi: 10.1016/j.clae.2018.05.002

 

JEFFREY SONSINO, OD, FAAO specializes in advanced contact lenses. He practices at Optique in Tennessee.

 

**Medical procedures, case studies, and practices mentioned in this content may vary based on regional standards, local regulations, and the discretion of providing healthcare professional. What may be considered appropriate and ethical in one country may differ in another.

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