Evaluation of an opacity lensometer for determining corneal clarity following excimer laser photoablation

Journal Article · Sat Sep 01 04:00:00 EDT 1990 · Refractive and Corneal Surgery; (USA)

OSTI ID:5982366

Andrade, H A; McDonald, M B; Liu, J C; Abdelmegeed, M; Varnell, R; Sunderland, G ^[1]

---

1. Louisiana State Univ. Medical Center School of Medicine, New Orleans (USA)

The appearance of haze in the central cornea following photoablation with a 193 nm excimer laser is an important factor in the postoperative course of this procedure. Data from 37 human eyes treated with photorefractive keratectomy, 4 eyes treated with phototherapeutic keratectomy, and 5 untreated eyes were used to evaluate the ability of a commercially available opacity lensometer to provide an objective measure of corneal clarity. We found that the opacity lensometer was able to detect light scattered from the cornea but was not sufficiently sensitive to distinguish reliably among excimer-treated eyes with degrees of corneal haze evaluated as clear, trace, or 1+ by slit-lamp microscope examination. In untreated, clear corneas, the values obtained with the opacity lensometer in eyes measured with and without a clear contact lens were within one unit of each other for any given eye, but values from eye to eye varied over a range of six units. In a test simulating different amounts of corneal haze using contact lenses evenly coated with nail polish enamel, the log-transformed opacity lensometer values varied directly with percent light scattering as determined by spectrophotometry. These results suggest that the opacity lensometer measurements are reliable and reproducible, but that in the human cornea something is being measured by the opacity lensometer that is not taken into account in clinical slit-lamp microscope evaluation. Overall, it appears that, in its present form, this instrument is not useful to measure corneal clarity after excimer laser photoablation.

• OSTI ID: 5982366
• Journal Information: Refractive and Corneal Surgery; (USA), Journal Name: Refractive and Corneal Surgery; (USA) Vol. 6:5; ISSN RCSUE; ISSN 1042-962X
• Country of Publication: United States
• Language: English

Related Subjects

560400* -- Other Environmental Pollutant Effects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ANIMALS
BIOLOGICAL EFFECTS
BODY
BODY AREAS
CORNEA
ELECTROMAGNETIC RADIATION
EXCIMER LASERS
EYES
FACE
GAS LASERS
HEAD
LASER RADIATION
LASERS
MAMMALS
MAN
MEDICINE
OPACITY
OPHTHALMOLOGY
OPTICAL PROPERTIES
ORGANS
PATHOLOGICAL CHANGES
PHYSICAL PROPERTIES
PRIMATES
RADIATIONS
SENSE ORGANS
VERTEBRATES