The pattern and morphology of cellular infiltration of iris melanocytes implanted into the corneal stroma were studied with a rabbit corneal model. Iris melanocytes are transformed into fibroblast-like cells with a loss of pigment granules, which may reflect the in vivo characteristics of iris melanocytes under pathologic conditions. The metaplastic chararter of iris melanocytes appears to be related to the formation of retrocorneal pigmentation and fibrous membrane.
Animals ; Cell Division ; Cornea/*cytology/pathology/surgery ; Iris/*cytology ; Melanocytes/*cytology/physiology/transplantation ; Metaplasia/pathology ; Rabbits

BACKGROUNDLaser in situ keratomileusis (LASIK) has become an efficient and commonly performed procedure to reduce refractive errors. In order to further increase the postoperative visual quality, the wavefront-guided refractive surgery has been a research hotspot in customized surgery. This study was conducted to compare the visual acuity, higher-order aberration, and contrast sensitivity of wavefront-guided LASIK with iris-registration and conventional LASIK.

METHODSTwo hundred and eleven myopic eyes of 109 patients were enrolled in this prospective study and randomly divided into two groups: the wavefront-guided LASIK (wg LASIK) group (94 eyes) and conventional LASIK group (117 eyes). A Wavescan Wavefront aberrometer was used to analyze Zernike coefficients and the root-mean-square (RMS) of higher order aberrations with 6.0 mm pupil size, and Optec 6500 visual function instrument was used to measure contrast sensitivity (CS) under 5 spatial frequencies before and after surgery in both groups.

RESULTSThe uncorrected visual acuity (UCVA) and the mean spherical equivalent (SE) in wg LASIK group were significantly better than those in conventional LASIK (UCVA, z = 2.339, P = 0.019; SE, t = 2.838, P = 0.005) at 3 months after surgery. Moreover, the increase in Z(3)(-3), Z(3)(1), Z(3)(3), Z(4)(0), Z(5)(-1), Z(5)(1), Z(5)(5) and Z(6)(-6) in wg LASIK group was statistically smaller than that in conventional LASIK group (P < 0.05). In wg LASIK group, eyes with a higher amount of the preoperative RMS of the higher order aberrations (RMSh = 0.30 microm) showed a statistically lower increase (13.5%) than those in conventional LASIK group at 3 months after surgery (33.3%) (P = 0.004). And the values of 4th order spherical aberration (4thSA) and the root mean square of 6th order aberration (RMS6) in wg LASIK group were significantly lower than those in conventional group in eyes which had higher preoperative astigmatism (= 1.0D) (4thSA, P = 0.03; RMS6, P = 0.02). Wg LASIK group showed better CS values than the correspondingly preoperative values at all spatial frequencies with and without glare at 3 months after the surgery while conventional LASIK group displayed reduced CS values except for 1.5 and 3 cycles per degree with glare. The differences between the two groups were statistically significant (P < 0.001).

CONCLUSIONSWavefront-guided LASIK with iris-registration is efficient to reduce higher order aberrations especially spherical and coma aberrations, and to improve postoperative visual acuity and contrast sensitivity compared with conventional LASIK. The application of wavefront-guided LASIK with iris-registration is particularly suitable for eyes with higher preoperative RMSh values and eyes with higher preoperative astigmatism.

Contrast Sensitivity ; Humans ; Iris ; cytology ; Keratomileusis, Laser In Situ ; methods ; Refraction, Ocular ; Visual Acuity

PURPOSE: This study was performed to examine the vascular network of the human iris using flat preparation. METHODS: The ciliary body-iris structures were separated from human eyeballs, and a portion of the irises were treated with trypsin to remove the pigment granules. These iris tissues were unfolded and placed onto glass slides using flat preparation, and the vascular network of each iris was examined by fluorescein microscopy. The ciliary body-iris structures separated from the remaining eyes were stained with hematoxylin-eosin without trypsin treatment and were examined by light microscopy. RESULTS: The long posterior ciliary artery formed several branches before entering the iris root, and such branches formed the major arterial circle of the iris with diverse diameters in the vicinity of the iris root and the ciliary process. In the pupillary margin, the iris vasculature network formed a cone shape and then formed an arcade by connecting to adjacent vasculatures. In the vicinity of the collarette, the iris vasculature network formed the minor arterial circle of the iris with diverse diameters perpendicular to the arcade of the iris network located in the pupillary margin. In the pupillary margin, the capillaries were somewhat thick and connected to the irregular traveling iris vein. CONCLUSIONS: The above findings explain the human iris vascular network and provide a theoretical basis for the sectoral filling of the iris vasculature seen in fluorescein iris angiography.
Cadaver ; Cytological Techniques/*methods ; Humans ; Infant ; Infant, Newborn ; Iris/*blood supply ; Microscopy, Fluorescence ; Ophthalmic Artery/*cytology ; Veins/*cytology