This article is more than 5 years old. Information may no longer be current.
Gradual loss of vision associated with bilateral anterior stromal opacities
A man presented with a 5-year history of vision loss.
Click Here to Manage Email Alerts
A 53-year-old man presented to our eye clinic with complaints of painless gradual vision loss in both eyes over the past 5 years. He had a history of hard contact lens wear and dry eyes. The patient had no other significant medical history but admitted there was a family history of a “corneal problem” in his mother, son and cousins.
Examination
On examination, the patient’s best corrected visual acuity was 20/60 in the right eye and 20/70 in the left eye. There was no improvement in visual acuity with manifest refraction. His pupils were round and reactive to light. Extraocular motility was full. Anterior segment examination of both eyes revealed diffuse anterior stromal honeycomb-like opacities (Figures 1 and 2) with areas of punctate elevation noted bilaterally (Figure 3). Posterior segment examination was unremarkable.
Figure 1. Slit lamp photograph of the left eye showed diffuse stromal honeycomb-like opacities.
Images: Bhavsar K, Raizman MB
Figure 2. Slit beam photo of the left eye revealed the anterior location of the corneal stromal opacities.
Figure 3. Multiple areas of elevation as seen on slit lamp photo of the left eye.
What is your diagnosis?
Anterior stromal opacities
The differential diagnosis of bilateral anterior stromal opacities with a honeycomb appearance in the setting of positive family history includes corneal dystrophies of Bowman’s layer and of the stroma. Dystrophies of Bowman’s layer include Thiel-Behnke and Reis-Bücklers, while those of the stroma include granular (type 1), Avellino (type 2), macular and fleck dystrophy (François-Neetens).
Dystrophies of Bowman’s layer and the stroma are typically differentiated by the characteristic clinical appearance and depth of corneal opacities, as well as by pertinent family history. In our patient, the location of the corneal opacities was very anterior, and an autosomal dominant mode of inheritance was suspected. The clinical appearance seemed to be most consistent with Reis-Bücklers dystrophy, which is defined by honeycomb-like corneal opacities in a geographic pattern concentrated centrally.
Diagnosis and management
The diagnosis of Reis-Bücklers dystrophy was made based on the characteristic clinical features observed in our patient. Corneal pachymetry was then obtained, and central corneal thicknesses were found to be 525 µm in the right eye and 520 µm in the left eye. Corneal topography revealed 4.9 D of irregular astigmatism at 79° in the right eye and 4.6 D of irregular astigmatism at 67° in the left eye.
A trial of scleral lenses was discussed with the patient as a potential treatment option, but he deferred due to unease with contact lens wear. Surgical options were also discussed, including phototherapeutic keratectomy (PTK) to improve the corneal surface and his vision. The patient was agreeable to this and subsequently underwent PTK with adjunctive mitomycin C (0.2 mg/mL) in the right eye, which was more symptomatic. A 6.5-mm ablation zone was utilized, and the total ablation depth was approximately 50 µm. Hyperopic correction with PRK was also performed using a 9-mm ablation diameter and 40-µm ablation depth.
At the 1-month follow-up, the patient’s visual acuity had improved to 20/40 and his anterior segment exam revealed decreased corneal opacities in the right eye. Eight months later, his vision was 20/25 with a smoother corneal surface and significant clearing of the corneal opacities and haze (Figure 4). Corneal topography revealed decreased irregular astigmatism of 1.3 D at 65°.
Discussion
Reis-Bücklers dystrophy was initially described in 1917 and is characterized by autosomal dominant inheritance. It typically develops in early childhood and is marked by recurrent painful erosions in the first 3 decades of life. Patients then experience a progressive decline in visual acuity, either from the corneal opacities or surface irregularity. Genetic and molecular analysis has found that a mutation of transforming growth factor beta-induced gene is implicated in this dystrophy, and subsequently, abnormal keratoepithelin is produced.
Figure 4. Improved corneal surface, haze and opacities 9 months after PTK in the right eye.
Reis-Bücklers dystrophy primarily affects Bowman’s layer and the superficial stroma. Pathologic evaluation reveals increased fibroblast activity with fibrocellular material or scar tissue replacing Bowman’s layer in a “sawtooth” pattern. As in our patient, the clinical appearance is typified by honeycomb-like corneal opacities in a geographic pattern located in the central cornea. Appearance is typically symmetric between eyes.
Intervention is indicated for patients with visual decline or surface pain. Initial management options include treatment for recurrent erosions (bandage contact lens, lubrication) as well as scleral lenses. Surgical management can be explored, including superficial keratectomy for epithelial irregularity and superficial scarring, PTK, lamellar keratoplasty and penetrating keratoplasty. Treatment history and corneal pachymetry are useful in dictating surgical management.
Although there are multiple treatment options, risk of recurrence should always be discussed with the patient. Dinh et al evaluated recurrence in patients with Reis-Bücklers dystrophy after treatment with PTK, and a relatively high rate of recurrence was detected (10 of 17 cases), the majority after 12 months. Orndahl and Fagerholm reported minimal recurrence in two cases following PTK, with disease recurrence noted at the edge of the treatment zone after 1 year. Overall, patients with Reis-Bücklers usually require multiple PTK treatments, followed by PK when the cornea becomes too thin. Lamellar keratoplasty has a high rate of recurrence that can be difficult to treat due to interface disease and is thus deferred in favor of full-thickness grafting, for which recurrence can be re-treated with surface ablation.