Keratoconus and corneal morphology in patients with Down syndrome at a pediatric hospital.

PURPOSE: To evaluate patients with Down syndrome for keratoconus and corneal abnormalities using Scheimpflug imaging (Pentacam HR) in a pediatric setting. METHODS: The Pentacam scans of patients with Down syndrome seen at Children's Hospital Colorado Ophthalmology Department were reviewed retrospectively, and the following data were collected: keratometry values, pachymetry values, components of the Belin ABCD Grading System, the Belin/Ambrosio enhanced ectasia display D value, and topometric indices, including ISV, IVA, and KI. Subjective interpretation was used to classify scans as normal, abnormal, keratoconus suspect, and definite keratoconus. RESULTS: A total of 56 eyes of 31 patients aged 4-24 years (mean, 12.4) were included. The average value for K1 was 44.95 ± 1.73 D (range, 40.90-49.3 D); for K2, 46.87 ± 2.16 D (range, 42.50-51.80 D); for Kmax, 48.20 ± 3.11 D (range, 43-61.7 D); and for Kmean, 45.81 ± 1.85 D (range, 41.7-50.35 D). Mean pachymetry at the thinnest point was 509 ± 44.24 µm (range, 410-612 µm) and at the apex was 519 ± 44.24 µm (range, 412-646 µm). The mean D value was 2.08 ± 1.57 (range, 0.08-9.71). There were 10 patients (32%) with either keratoconus suspect or definite keratoconus in at least one eye. CONCLUSIONS: We found a high frequency of keratoconus and keratoconus suspect in pediatric and young adult patients with Down syndrome. The corneas in this population had steeper K values and thinner pachymetry values compared to previously reported controls.

Long-Term Tomographic Evaluation of Unilateral Keratoconus.

PURPOSE: To report 5 cases of advanced unilateral keratoconus documented by sequential tomographic evaluation. METHODS: Retrospective review over a 10-year period at a single practice identifying patients with unilateral keratoconus by advanced imaging throughout the follow-up period. RESULTS: Five patients were identified with progressive keratoconus in 1 eye and no changes in the fellow eye based on full tomographic evaluation and analysis of both anterior and posterior corneal surfaces and corneal thickness with a mean follow-up period of 59 months (range 39-86). CONCLUSIONS: Keratoconus is believed to be a bilateral disease that can present asymmetrically. We present 5 cases that appear to be true unilateral keratoconus with no associated mechanical environmental factors.

Incidence rate and occurrence of visually significant cataract formation and corneal decompensation after implantation of Verisyse/Artisan phakic intraocular lens.

PURPOSE: To evaluate the incidence rate and indications for explantation of Verisyse phakic intraocular lenses (pIOLs) over a 13.6 year period. SUBJECTS AND METHODS: Case series describing six cases of explantation of Verisyse pIOLs, out of 213 eyes with Verisyse pIOLs, implanted over a 13.6 year period by one surgeon at one institution, with mean follow-up of 5.6 years per eye. RESULTS: Four pIOLs were removed to facilitate extraction of a visually significant cataract, one was removed due to both cataract formation and development of corneal decompensation, and another was removed due to development of localized peripheral corneal decompensation. The incidence rate of pIOL removal was five per 1,000 patient-years with pIOL. Mean time from insertion of pIOL to cataract removal was 9.3 years (range 4.0-12.6 years). Mean time from insertion of pIOL to development of corneal decompensation was 10 years (range 6.9-13 years). There was no increase in the rate of cataract extraction in the pIOL population compared to the general population. CONCLUSION: Cataracts may develop in patients with pIOLs, necessitating removal of the pIOL. Corneal decompensation is a serious complication that appears to be directly related to pIOLs. Corneal decompensation can occur up to 13 years following implantation of pIOLs, and long-term follow-up is important to monitor for this complication.

In vitro pilot analysis of uniformity, circularity, and concentricity of DSAEK donor endothelial grafts prepared by a microkeratome.

PURPOSE: The aim of this study was to analyze Descemet stripping automated endothelial keratoplasty donor endothelial grafts, prepared by using a microkeratome, in terms of uniformity, circularity, and concentricity. METHODS: In this pilot study, 12 human donor corneas were prepared by means of a microkeratome and imaged using the Visante anterior segment optical coherence tomography along 4 meridians. The microkeratome enters and exits the corneal tissue at an angle, creating a donor graft bed with a uniform stromal (US) thickness in between the angled edges. We termed the angled portion the "nonuniform stromal transitional annulus" (STA), the point of entry and exit of the microkeratome the "epithelium-to-epithelium" (E-E) diameter, and the length of the US bed the "US" diameter. The E-E and US diameters were measured to create a model of each donor graft, from which circularity and concentricity were calculated. The STA length and height were measured, and the slope was calculated. RESULTS: The mean E-E diameter was 10.69 ± 0.32 mm (range, 9.46-11.75 mm) and the mean US diameter was 8.96 ± 0.40 mm (range, 7.62-10.28 mm). The microkeratome generated elliptical rather than circular cuts, with a mean eccentricity of 0.34 ± 0.098 (range, 0.22-0.58). Eccentricity values between 0 and 1 represent ellipses, with zero characterizing a circle. The US ellipses and E-E ellipses were not concentric, with a mean deviation of the centers of the shapes of 177.06 ± 92.06 µm (range, 21.95-322.22 µm). The mean STA length was 0.73 ± 0.31 mm (range, 0.25-1.89 mm), the mean height was 0.43 ± 0.08 mm (range, 0.28-0.64 mm), and the mean slope was 34.11 ± 14.00° (range, 8.43-53.67°). CONCLUSIONS: Microkeratome cuts created nonuniform, noncircular nonconcentric donor grafts. Asymmetry and nonuniformity of donor tissue may help explain suboptimal visual outcomes.