Microcyst, epithelial

Epithelial microcysts are an abnormal corneal response at the cellular level to chronic hypoxia from contact lens wear. When present, they tend to be observed in soft contact lens wearers, particularly those wearing extended-wear lenses. A hypoxic state can result in the development of microcysts due to such causes as... 

The soft contact lens patient who becomes symptomatic from epithelial microcysts tends to develop symptoms rather suddenly after uneventful contact lens wear. It is not uncommon for the patient with microcysts to have been remiss in timely follow-up care, when the formation of microcysts may have been detected before symptoms developed. Symptoms associated with this condition include burning, foreign body sensation, tearing, and photophobia, all likely related to the disrupted epithelium. Decreased visual acuity results, even with the best spectacle correction in place, because of the now irregular corneal surfece. 

Epithelial microcysts may take weeks to months to resolve, althongh the therapy described above is generally needed only for the first 1 or 2 weeks after acnte presentation. Once the patient becomes asymptomatic, it can be a challenging management issne to convince the patient that contact lens wear shonld be discontinned imtil the corneal tissue is healed. While corneal healing is being... 

Figure 26-60 Epithelial microcysts observed in diffuse illumination (A) and with NaFl staining (B) secondary to soft contact lens wear.

Corneal edema is a common finding postoperatively after uncomplicated, sutureless, scleral tunnel or clear corneal incision cataract surgery. More severe involvement (Figure 30-5) with persistent stromal edema, epithelial microcysts, and bullae may be found in patients with low endothelial cell counts, excessive inflammation from corneal trauma during the surgery, or an increased lOP secondary to retained lens material or inflammatory response. Bullae are typically secondary to increased corneal aqueous absorption due to high lOP or to a breakdown of the corneal endothelial aqueous pump. 

In addition to a frank epithelial defect that stains with NaFl, epithelial edema, microcysts, and poor epithelial attachment may be seen in acute cases of RCE. If the... 

An ABMD may be evident. Classic findings of ABMD include intraepithelial geographic opacities, microcysts, and concentric refractile lesions that resemble fingerprints. The use of retroillumination is helpful in viewing the epithelial defects with the slit-lamp biomicroscope. 

Mild to moderate conjunctival injection occurs and may be enhanced in the perilimbal area. Careful slit-lamp examination reveals a dense collection of tiny, clear, epithelial cysts in the central cornea. This appearance is best viewed using indirect illumination and retroillumina-tion techniques (Figure 26-60). Instillation of NaFl reveals an irregular central epithelial surface with almost a discoid collection of punctate positive and negative stains. Positive stains occur when the microcysts have emptied onto the epithelial surfece and caused microerosions negative stains occur over the tiny bumps in the epithelium where the microcysts have invaded the epithelium but not yet eroded it. 

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