prescribing for astigmatism

Managing Severe EBMD

BY VISHAKHA THAKRAR, OD, FAAO

Epithelial basement membrane dystrophy (EBMD), a condition resulting in an abnormal basement membrane, is the most common corneal dystrophy Slit lamp examination typically reveals projections of abnormal multilaminar basement membrane into the epithelium (maps), intraepithelial cysts (dots), and projections of fibrogranular material into the epithelium (fingerprint). In severe cases, this results in irregular astigmatism and recurrent corneal erosions (RCEs).

A Case of Severe EBMD

A 54-year-old white female who had Stevens-Johnson syndrome presented to the office for contact lens fitting. She had a history of EBMD with subsequent RCEs OD and OS. Her corneal specialist had conducted a superficial keratectomy and stromal puncture in both eyes in the past, but these procedures did not control the occurrence of the RCEs. Several months prior to this initial visit, she had a severe corneal ulcer OS that required amniotic membrane transplantation. At this point, her corneal specialist felt that it was safe for her to return to contact lens wear. Medications included Vigamox (Alcon) b.i.d. and Pred Forte 1% (Allergan) b.i.d. OS.

The patient had previously worn piggyback lenses OD and a soft contact lens OS on a daily wear basis. She did not experience abrasions during the day while she was wearing lenses, but often experienced abrasions upon waking. She had tried different methods of lubricating the ocular surface overnight to avoid erosions with limited success. Slit lamp examination revealed superior and inferior basement membrane changes and central corneal scarring in both eyes. She also demonstrated dry eye secondary to the Stevens-Johnson disease. The topography map (Figure 1) revealed flat corneas OD and OS.

Figure 1. Flat corneas in a patient who has severe EBMD.

A Different Approach

At this visit, the patient inquired about sleeping in her contact lenses because the erosions did not occur when she wore them. With the history of a severe corneal ulcer, I was hesitant to agree. I consulted with her corneal specialist, and we decided to proceed with allowing her to wear soft contact lenses on an extended wear basis.

She was successfully fit OD with PureVision (Bausch + Lomb), 8.6mm base curve, −1.00D and OS with Night & Day (Ciba Vision), 8.6mm base curve, −5.00D. We refit the GP OD to Menicon Z (Menicon), 8.3mm base curve, 9.5mm diameter, −4.75D and OS to Menicon Z, 8.5mm base curve, 9.5mm diameter, −3.25D. Visual acuities were 20/40 OD and 20/20 OS with this combination. She began wearing the soft lenses on an extended wear basis, removing and cleaning them every seven days. She wore the GPs daytime only.

At the one-week follow up the patient had trace corneal edema, but she did not experience corneal abrasions. Subsequent follow-up visits revealed no further increase in corneal edema. She has worn this lens combination for four years with few corneal abrasions and no corneal ulcers.

This case describes a nontraditional method of fitting a corneal dystrophy. For this patient, the extended wear option seemed viable to prevent RCE. She required very close monitoring to ensure that the extended wear schedule did not result in a subsequent infection, particularly because of the compromise to the ocular surface from the Stevens-Johnson syndrome. CLS

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Dr. Thakrar has a specialty contact lens practice and is a clinical optometrist at TLC Laser Eye Center in Mississauga, Ontario. She is also a professional affairs consultant to Vistakon.