Prevalence of Keratoconus Based on Scheimpflug Corneal Tomography Metrics in a Pediatric Population From a Chicago-Based School Age Vision Clinic

PURPOSE

Determine the pediatric prevalence of keratoconus (KC) using Scheimpflug corneal tomography.

METHODS

A prospective observational study was done on subjects aged 3 to 18 years at the Princeton Vision Clinic, Chicago, IL. Scheimpflug tomography (Pentacam HR, OCULUS Optikgerate GmbH) scans (Belin/Ambrósio Enhanced Ectasia BAD3) yielded BAD Final D (Final D) and Back Elevation at the Thinnest Point (BETP) measurements. Criteria differentiating non-KC from KC suspects & KC were, Non-KC -Final D <2.00 in both eyes; KC suspect -Final D ≥2.00 and <3.00 in combination with BETP ≥18 μm for myopia and ≥28 μm for hyperopia/mixed astigmatism in at least one eye; and KC -Final D of ≥3.00 with BETP ≥18 μm for myopia or ≥28 μm for hyperopia/mixed astigmatism in at least one eye. Two thousand two hundred and six subjects were recorded, removing duplicate and poor-quality scans leaving 2007 subjects.

RESULTS

Of 2007 subjects, six were classified as KC -prevalence of 1:334, three subjects were KC suspects -prevalence of 1:669, and total prevalence of KC suspects and KC was 1:223.

CONCLUSION

The prevalence of KC in children is higher than previously reported, emphasizing the importance of sensitive screening for KC at its earliest manifestation as standard in pediatric comprehensive eye examinations.

Transverse keratotomy followed by LASIK for the treatment of naturally occurring astigmatism

PURPOSE

To evaluate the efficacy of transverse keratotomy followed by LASIK for patients with high amounts of naturally occurring astigmatism.

METHODS

Thirteen eyes with naturally occurring astigmatism ranging from -3.75 to -6.50 diopters (D) underwent sequential transverse keratotomy (60 degrees at 6 mm) and LASIK procedures. The effect of these two procedures on the amount of astigmatism was studied.

RESULTS

Transverse keratotomy led to a 46% reduction in refractive cylinder from -5.50 +/- 0.80 D to -3.00 +/- 1.00 D. After LASIK, the initial refractive astigmatism was reduced by 90% to -0.50 +/- 0.50 D with a minimum follow-up of 6 months.

CONCLUSIONS

The combined technique of transverse keratotomy followed by LASIK is an effective and accurate way to treat high amounts of naturally occurring astigmatism, allowing the size of the optical zone of the excimer laser ablation to be maximized.