Tracking Down a Diagnosis
By Leo Semes, OD, FAAO
A 40-year-old male presented for an eye examination with vague complaints of irritation and blur in the right eye only. He was taking no medications and had good results from a recent physical examination. The personal and family medical histories were non-contributory. He denied trauma as well as allergies.
Visual acuity without correction was 20/20 in each eye. Slit lamp examination was unremarkable in each eye with the exception of very mild perilimbal injection OD only. The anterior chamber angles of each eye appeared open by van Herick estimation. High magnification revealed no anterior chamber reaction in either eye. There was a mild papillary response of the right inferior palpebral conjunctiva and no fluorescein staining of either the cornea or the conjunctiva.
On further questioning, the patient admitted to mild itching for the past two or three days that produced minimal tearing. The intraocular pressure was 12 mmHg in each eye using Gold-mann tonometry. The mild conjunctival injection disappeared following dilation (0.5% tropicamide plus 2.5% phenylephrine).
The patient was advised to use Alaway (ketotifen, Bausch + Lomb [B+L]) b.i.d. OD for the mild allergic response and to return in one year unless vision or irritative symptoms arose.
A Second Exam
The patient called back three days later complaining of blurred vision in the right eye. He confirmed that he had used the anti-allergy drops as directed. On examination, visual acuity had dropped to 20/40 in the right eye but remained stable at 20/20 in the left eye. The slit lamp examination revealed one small (1mm) curvilinear and two smaller punctate epithelial disruptions just below and nasal to the visual axis. The lesions stained with fluorescein as well as lissamine green. The mild papillary response of the inferior palpebral conjunctiva was still present. The anterior chamber examination did not reveal cells or flare. The left eye as well as the posterior pole of each eye remained unchanged.
We considered a working diagnosis of Herpes simplex keratitis (HSK). The patient at this point denied a history of cold sores. He further allowed that a co-worker had been treated for HSK for the previous two weeks.
Finally, the Whole Story
On further questioning, the patient admitted to having used some Lotemax (loteprednol, B+L) drops that had been prescribed for his 8-year-old son.
At this point, we prescribed Zirgan (ganciclovir gel, B+L) for application to the right eye five times daily. The return visit two days later demonstrated a VA of 20/25 in the right eye and diminution of the lesions but appearance of subepithelial infiltrates (SEIs) surrounding the initial lesions. Differential diagnoses considered at this time included Thygessons SPK and epidemic keratoconjunctivitis (EKC), but there was an absence of bilateral presentation and lack of significant conjunctival inflammatory response, respectively. Zirgan was continued at five times per day.
At re-evaluation three days later, the corneal epithelium had completely healed without any vital dye staining. Scattered SEIs remained, and Zirgan dosing was reduced to three times per day. We also prescribed a combination of tobramycin and dexamethasone (TobraDex ST, Allergan) q.i.d. for an additional seven days. At the return visit, the cornea of the right eye had completely cleared.
This case illustrates television's Dr. House's premise: all patients lie. Not that our patient deliberately withheld anything, but he failed to reveal the self treatment. This case also illustrates the use of a new simplified formulation for HSK (Zirgan) and the incorporation of the recently FDA-approved combination TobraDex ST suspension. CLS
Dr. Semes is a professor of optometry at the UAB School of Optometry. He is also a consultant or advisor to Alcon, Allergan, Opto-Vue, and Zeiss.