[In vivo confocal corneal microscopy after keratoplasty]. / Konfokale In-vivo-Hornhautmikroskopie nach Keratoplastik.

BACKGROUND: Seven eyes with clear grafts after penetrating keratoplasty were examined with in vivo confocal corneal microscopy in 1999. Our aim was the confocal microscopic investigation of the subclinical changes in clear grafts after long-term follow-up. METHODS: The preoperative diagnoses were keratoconus (two), granular corneal dystrophy (two), pseudophakic bullous keratopathy due to ACL (two), and corneal ulcer (one). The epithelium, corneal nerves, keratocytes of the anterior and posterior stroma, and endothelium were evaluated with confocal microscopy. RESULTS: Mean density of basal epithelial cells was 3928+/-378 cells/mm(2) at 15 months and 3284+/-565 cells/mm(2) at 66 months postoperatively. At 15 months the keratocyte density was 750+/-113 cells/mm(2) in the anterior stroma and 601+/-98 cells/mm(2) in the posterior stroma, at 66 months 383+/-53 cells/mm(2) in the anterior stroma and 411+/-98 cells/mm(2) in the posterior stroma. Endothelial cell density decreased from 1719+/-576 cells/mm(2) (15 months) to 965+/-272 cells/mm(2) (66 months). CONCLUSIONS: 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.

Reliability and reproducibility of corneal endothelial image analysis by in vivo confocal microscopy.

BACKGROUND: The aim of our study was to evaluate the reliability and reproducibility of in vivo slit-scanning corneal microscopy by endothelial analysis. METHODS: We examined 12 normal eyes of 12 persons. We analysed intraobserver differences in group I and interobserver differences in group II by manual and automatic evaluation of endothelial images. We also compared the methods of analysis in the two groups. We observed endothelial density, mean cell area, coefficient of variation and number of cells within the frame. RESULTS: In group I we found no significant difference between the observed parameters either by automatic or manual analysis. In group II no significant difference between the two observers was found using automatic analysis. On manual analysis, however, we observed a significant difference between endothelial density and the number of evaluated cells (P=0.0034 and P=0.0028). We observed a significant difference (P<0.001) between automatic and manual analysis concerning each parameter, with a rather tight linear correlation (Pearson correlation between 0.76 and 0.94). CONCLUSION: 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.

Scanning laser polarimetry in corneal haze after excimer laser refractive surgery.

PURPOSE: We evaluate the technique of retinal nerve fiber layer thickness measurement using scanning laser polarimetry in cases of central corneal haze due to photorefractive keratectomy. METHODS: Nerve fiber layer thickness was measured using a Nerve Fiber Analyzer II (Laser Diagnostic Technologies, Inc., San Diego, CA, U.S.A.) in eight eyes of eight individuals with mild to pronounced corneal haze owing to earlier excimer laser refractive surgery, and in nine eyes of nine control volunteers. RESULTS: Neither total and sectorial nerve fiber layer thickness values, nor superior/ inferior quadrant thickness ratio differed in a statistically significant manner between the two groups (unpaired t test, p > 0.05). Reproducibility in the "haze" and control groups was 4.3% and 3.4%, respectively, for mean nerve fiber layer thickness calculated from all quadrants around the disc. The figures were 4.9% and 5.2%, respectively, for the superior quadrant thickness; 8.2% and 8.8%, respectively, for the temporal thickness values; 5.4% and 4.6%, respectively, for the inferior thickness values; and 4.1% and 5.0%, respectively, for the nasal quadrant thickness values. For the superior/inferior quadrant thickness ratio the reproducibility was 4.4% and 6.8%, respectively. None of the corresponding values for reproducibility differed significantly between the two groups (F-test, p > 0.05). CONCLUSIONS: Corneal haze did not cause an artificial increase of the thickness values measured with scanning laser polarimetry and did not diminish the reproducibility of the measurement. The results suggest that scanning laser polarimetry may be a suitable method for the precise measurement of the nerve fiber layer thickness even in eyes with persistent corneal haze after excimer laser refractive surgery.

Scanning laser polarimetry of the retinal nerve fibre layer in primary open angle and capsular glaucoma.

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 suffering from POAG, 25 patients suffering 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 differed between the two glaucoma groups. Reproducibility was comparable in all groups; the coefficient of variation varied between 3.0% and 8.9% for the different 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.