& scleral lens wear
Lynette Johns OD FAAO FSLS
One complication of keratoconus and other ectatic disorders is acute hydrops. Descemet’s membrane ruptures, and the stroma and epithelium become edematous from the resulting inflow of aqueous. The symptoms can include blurry vision, pain, photophobia, excessive tearing and complaints of a “white spot” on the eye. Over time, the endothelial cells migrate, enlarge, and pump out the edema.
Once the hydrops has resolved, scleral lens wear may resume with sometimes surprising results.
A 38-year-old female with a history of keratoconus and corneal (R)GP lens intolerance was fit with scleral lenses OU in 2008. Her entering simulated keratometry readings were OD 64.6/71.7 @ 30° and OS 45.2/49.4 @ 62°. The best corrected vision with her devices was 20/50 OD and 20/20 OS. She complied with her annual visits.
Hydrops initial presentation
In May 2010 she arrived complaining of reduced vision, light sensitivity and a white spot on the right eye. There was inferior focal epithelial and stromal edema as well as a negative Seidel sign. The conjunctiva was moderately hyperemic. She diagnosed with a hydrops and was told to discontinue use of the OD device.
At the one-week visit, the patient was less symptomatic, the conjunctiva was white and the stromal edema was focal and distinct, but epithelial bullae were present.
In July 2010, she returned with improved comfort and minimal stromal and epithelial edema and was allowed to resume wearing her device. Her acuity after hydrops with her original device had dropped to 20/80 OD, but she pinholed to 20/30. The fit remained optimal and vaulted nicely over the cornea.
Hydrops 6 weeks later
Her original device had a base curve of 8.4, power of +7.50, and eccentricity of 0.8, and her newest device had a base curve of 7.9, power of +0.25 and eccentricity of 0.3. The new simulated keratometry readings were 58.8/65.5 @40° OD. The lens diameter and sagittal depth remained the same. We were able to improve her vision with a new device to 20/30+1 using a combination of base curve, power and front surface eccentricity change.
Acute hydrops can be very dramatic to a clinician and even more frightening to a patient. Hydrops is known to resolve on its own, but the epithelial edema may worsen by wearing a scleral lens. Once the edema resolves, the patient may resume scleral lens wear. Sometimes the refraction may change as a result of the corneal flattening and may have resultant effects on higher-order aberrations. The dense scar may mislead clinicians to refer affected patients for a transplant, but exploring all refractive options with a scleral lens may render surgery unnecessary.
Dr. Lynette Johns has been the senior optometrist at the Boston Foundation for Sight since 2005.
She is a graduate of the New England College of Optometry where she completed a residency in cornea and contact lenses. She is adjunct clinical faculty at the New England College of Optometry.
Dr. Johns is a fellow of the American Academy of Optometry and a fellow of the Scleral Lens Education Society.