Editor's Note: This case report is part of a series by members of Intrepid Eye Society.
Corneal dystrophies are often inherited, bilateral, and progressive disorders in which abnormal material collects in the layers of the corneal structure. Accurate diagnosis of corneal dystrophies can be difficult due to their rarity and variable clinical presentation.
Valuable factors that can aid in proper diagnosis include:
• The patient’s family history
• Pinpointing which layers of the cornea are affected
• The clinical characteristics of the corneal deposits/opacities
A new 56-year-old white male presented with a chief complaint of gradually increasing visual haze over the past 10 years in both eyes.
The patient reported being diagnosed with an unknown corneal dystrophy for which he had undergone two previous phototherapeutic keratectomy (PTK) procedures in his left eye.
He also reported that his mother, brother, and possibly his maternal grandfather have had bilateral corneal abnormalities.
The patient’s medical history was significant for hyperlipidemia that was well controlled with simvastatin (Zocor, Merck).
Clinical findings included best-corrected visual acuities (BCVA) of 20/25 OD and 20/50 OS with entrance testing results within normal limits.
Upon biomicroscopic evaluation, corneal findings were significant for dense arcus 360 degrees, central stromal haze, and crystallization at the level of the epithelium/anterior stroma (Figure 1).
Dilated fundus exam yielded unremarkable posterior segment findings.
Anterior segment optical coherence tomography (OCT) revealed subepithelial hyper-reflectivity that correlates to areas of corneal crystallization (Figure 2).
Corneal topography indicated diffuse corneal irregularity and distortion in both eyes.
Pachymetry measured 589 µm and 346 µm OD and OS, respectively. The thin pachymetry reading OS is likely due to two previous PTK procedures.
Corneal sensitivity with cotton wisp revealed no intact sensitivity in the right eye and intact, but low sensitivity, in the left eye.
Differential diagnoses with similar crystalline corneal findings that needed to be considered when diagnosing this patient included the following:1
• Fluoroquinolone/chlorpromazine use. This patient had no history of using these medications, excluding this as a diagnosis.2
• Bietti crystalline dystrophy. Bietti crystalline dystrophy is a rare, autosomal recessive disorder accompanied by retinal disease that causes progressive night blindness.3 This patient had unremarkable posterior segment findings, ruling out this diagnosis.
• Cystinosis. Often, cystinosis results in kidney failure at an early age.4 This patient had no known kidney problems, making a diagnosis of cystinosis highly unlikely.
• Infectious crystalline keratopathy. Microbial in etiology, infectious crystalline keratopathy typically causes a branching crystalline pattern, which was not present in this patient.5
• Lymphoproliferative disorders (monoclonal gammopathy, multiple myeloma). These conditions can rarely result in corneal findings, but the patient would have a history of bone pain, multiple bone fractures, or bruising.6 This patient did not have these symptoms.
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