Reliability of the herpes simplex virus immunofluorescent test in corneal disease.

Herpetic ocular disease never produces well-identifiable morphological aspects. It is expensive, complicated and slow to culture Herpes simplex virus. The validity of the fluorescent monoclonal antibodies test was investigated using corneal cells with or without a sure herpetic lesion. The tests, on 36 cases without sure herpetic lesions, were always negative, while of the 42 patients with a clinically ascertained herpetic lesion, 38 were positive (90.5%) and 4 negative (9.5%), two of these on account of inadequate tissue preparations. Thus, this method can prove useful and reliable for diagnostic purposes.

Factors that affect keratotomy depth.

The authors investigated nine factors which can affect the depth of incisions performed during refractive keratotomy: (1) vertical vs oblique-cutting edge of the knife blade, (2) direction of cutting, (3) cutting velocity, (4) American vs Russian technique, (5) intraocular pressure (IOP), (6) initial vs final incisions, (7) sharpness of knife blade, (8) single vs double footplate, and (9) square vs double-edged blade. These variables were examined independently, performing at least 40 incisions for each experimental parameter studied. The depth of the resulting incisions was measured histologically using the micrometer eyepiece. The average and the standard deviation were calculated. The paired Student's t-test was used to establish significant differences between the two conditions investigated for each parameter. Factors that were demonstrated to increase significantly the depth of the incisions included: the vertical-cutting edge, the triple-edged diamond knife, the sharpness of the knife, and the single foot knife. High velocity in performing the incisions and, to a lesser extent, low IOP were the main factors that induced irregularity in depth.