Aims-To evaluate the clinical value of scanning laser polarimetry with the nerve fibre analyser type II in primary open angle glaucoma (POAG) and capsular glaucoma. Methods-Scanning laser polarimetry was performed on one eye of 30 patients suVering from POAG, 25 patients suVering from capsular glaucoma, and on 35 healthy control subjects. The retinal nerve fibre layer (RNFL) thickness values were compared among the groups. Reproducibility of the measurements was calculated and the influence of pilocarpine induced miosis on the results was investigated. Results-RNFL thickness in the superior and inferior sectors, as well as along the total circumference was significantly lower in both glaucoma groups than in the control eyes (p<0.05). None of the thickness values diVered between the two glaucoma groups. Reproducibility was comparable in all groups; the coeYcient of variation varied between 3.0% and 8.9% for the diVerent sectors investigated. Miosis had no significant impact either on the thickness values or on the reproducibility (p>0.05). Conclusion-The results suggest that scanning laser polarimetry is a useful method for nerve fibre layer analysis in glaucoma, and that it is not influenced by the pupil size. (Br J Ophthalmol 1997;81:857-861) Glaucoma is a progressive optic neuropathy which means that gradual loss of the nerve fibres causes diVuse and localised thinning of the retinal nerve fibre layer (RNFL). It is well known in clinical practice that RNFL defects are very early signs of glaucoma, since they represent the first step in the glaucomatous morphological loss in the retina.1 Analysis of RNFL properties using black and white photographs requires a well trained examiner and does not provide real quantitative information about the thickness. However, a recently developed computerised technique, scanning laser polarimetry, provides both qualitative and quantitative information on the morphology and thickness of the RNFL, and results are available within a few seconds. In order to test the clinical value of the method we calculated its reproducibility and compared RNFL thickness results for healthy eyes and for eyes suVering from primary open angle glaucoma and from capsular glaucoma. The impact of pilocarpine induced miosis on the thickness values and reproducibility was also investigated.

Automatic endothelial analysis was reliable and well reproducible in both--intraobserver and interobserver--groups. By manual evaluation, the clinical significance of interobserver differences can be disregarded. The differences between automatic and manual methods of analysis can be traced back to measurement technical reasons. We observed tight linear correlation between parameters. The data can be described well by linear regression. In vivo slit-scanning corneal microscopy may be an alternative to specular microscopic analyses for clinical use.

Corneal photoablation with the 193 nm argon fluoride excimer laser during photorefractive keratectomy (PRK) in high diopter range is frequently associated with subepithelial haze and consequent refractive regression due to avascular corneal wound healing. The wound healing response can be augmented by Ultraviolet-B (UV-B) exposure originating from sun or solarium. Clinically Laser in situ Keratomileusis (LASIK) even in high diopter range is associated with less subepithelial haze and regression than PRK. In an animal model, the morphologic changes of the rabbit cornea were evaluated following LASIK and secondary UV-B exposure. Light microscpic changes were found to be insignificant. Transmission electron microscopy (TEM) normal epithelium, epithelial adhesion structures and normal anterior stroma showed in the LASIK treated UV-B irradiated rabbit eyes. Around the peripheral LASIK cut, migrating keratocytes with pseudopodia were observed. Under the flap (160 microm depth) the overall stromal collagen structure was normal, some activated keratocytes and mild extracellular matrix formation within and around keratocytes were noted. Within activated keratocytes TEM showed prominent rough endoplasmic reticulum, Golgi apparatus, mitochondria and extracellular vacuoles, which showed resolution with time. These changes were much milder than in PRK treated-UV-B irradiated eyes. Secondary UV-B caused no long-term disturbance in corneal transparency in LASIK and UV-B treated rabbit eyes.

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In the follow-up period a significant decrease of keratocyte and endothelial cell density was detectable with confocal microscopy. The clinical importance of our findings must be clarified with further examinations on more patients.