Empirical advanced orthokeratology through corneal topography: the University of Houston clinical study.

PURPOSE: Traditionally, orthokeratology has used diagnostic lenses to determine the best fit. The purpose of this study was to determine the efficacy of fitting empirically from corneal topography, without the use of diagnostic lenses. METHODS: Twenty-nine subjects, 18 to 37 years old, with myopia of 1.00 to 4.00 diopters (D) and astigmatism of no more than 1.50 D, were entered into this 6-month study. Corneal topography, scanning slit topography and corneal thickness (Orbscan), confocal microscopy, ultrasound corneal thickness, aberrometry, and biomicroscopy were used to assess corneal changes. Unaided logMAR high-contrast visual acuity, subjective refraction, and questionnaires were used to monitor vision and symptoms. Follow-up visits were scheduled after 1 day, 1 week, 2 weeks, 1 month, 3 months, and 6 months. RESULTS: For 6-month data, unaided logMAR acuity improved from 0.78 +/- 0.26 in the right eye and 0.75 +/- 0.22 in the left eye to 0.06 +/- 0.18 in the right eye and 0.04 +/- 0.16 in the left eye. Myopia decreased from -2.55 +/- 0.87 D in the right eye and -2.47 +/- 0.89 D in the left eye to +0.45 +/- 0.74 D in the right eye and -0.17 +/- 0.69 D in the left eye. Shape factor, using corneal topography, increased from 0.85 +/- 0.13 in the right eye and 0.85 +/- 0.15 in the left eye to 1.28 +/- 0.32 in the right eye and 1.30 +/- 0.29 in the left eye. Both eyes showed a decrease in lower-order aberrations (i.e., defocus) and an increase in higher-order aberrations (i.e., spherical aberrations and coma). CONCLUSIONS: Myopia reduction after 1 week was clinically insignificant from the 1-month results, indicating that the full effect is achieved by 1 week. Neither total nor epithelial corneal thickness varied significantly from baseline measurements.

Peripheral pigmentary iris cyst: evaluation and differential diagnosis.

Peripheral iris pigment epithelial cysts are benign lesions of the anterior segment. They are located at the iridociliary junction and can produce a localised distortion and/or displacement of the iris. Patients who have these lesions are usually asymptomatic and in the absence of a careful slitlamp examination will often remain undetected. The aetiology of these cysts is unknown and they tend to be unilateral and solitary in nature. The cyst walls are composed of iris pigment epithelium and the lumen contains clear fluid. Women are three times more likely to develop these cysts, which must be differentiated from malignancies of the iris or ciliary body. We report a case involving a peripheral pigmentary iris cyst and discuss methods of differentiating this benign lesion from serious ocular tumours.