Comparison of visual results in initial and re-treatment laser in situ keratomileusis procedures for myopia and astigmatism.

PURPOSE: To report the results of initial and re-treatment laser in situ keratomileusis procedures for myopia and astigmatism. METHODS: A total of 1161 consecutive inital and retreatment laser in situ keratomileusis procedures in 697 patients performed between September 19, 1996, and June 20, 1998, were retrospectively analyzed. Baseline and postoperative best spectacle-corrected visual acuity, uncorrected visual acuity, spherical and cylindrical refractions, computerized video keratography, and biomicroscopy were measured or performed on each eye. RESULTS: Of 1,071 eyes, 900 (84%) underwent a single-laser in situ keratomileusis procedure, and 171 of 1,071 eyes (16%) underwent one or two re-treatment procedures. The preoperative mean +/- SD spherical equivalent was -5.09 +/- 3.15 diopters (range, -0.75 to -14.38 diopters) and the cylinder was 0.97 +/- 1.09 diopters (range, 0.00 to 3.25 diopters) in the group that underwent a single laser in situ keratomileusis treatment. The preoperative mean +/- SD spherical equivalent was -6.26 +/- 3.04 diopters (range, -1.75 to -12.88 diopters) and the cylinder was 1.53 +/- 1.11 diopters (range, 0.00 to 3.50 diopters) in the group that underwent re-treatment. Before re-treatment, 110 eyes (64.3%) in the group that underwent re-treatment achieved 20/40 or better uncorrected visual acuity and 23 eyes (13.5%) achieved 20/25 or better. Three months after re-treatment, 155 eyes (90.6%) achieved 20/40 or better, and 80 eyes (46.8%) achieved 20/25 or better. In the single-procedure group, uncorrected visual acuity at 3 months revealed 20/40 vision or better in 856 eyes (95.1%) and 20/25 vision or better in 572 eyes (63.6%). In this study group, 23.6% of eyes with a preoperative spherical equivalent greater than -6.0 diopters underwent re-treatment compared with 11.8% of eyes with a preoperative spherical equivalent of -6.0 diopters or less. CONCLUSIONS: Laser in situ keratomileusis appears to be an effective procedure for mild, moderate, and severe myopia. In eyes with residual refractive error, re-treatment laser in situ keratomileusis procedures can result in good visual outcomes.

Changing trends in the indications for penetrating keratoplasty.

The indications for penetrating keratoplasty have changed over the past several years. Nine hundred ninety-nine penetrating keratoplasty specimens from 1981 through 1990 were analyzed. Overall, keratoconus was the most common indication for penetrating keratoplasty (24.2%). This was followed by pseudophakic bullous keratopathy (23.0%), regraft (13.1%), scarring (8.2%), and Fuchs' endothelial dystrophy (5.8%). Pseudophakic bullous keratopathy was the most common indication for penetrating keratoplasty in each year from 1984 through 1989 with a peak in 1987 (33%). Since 1987, the number of pseudophakic bullous keratopathy cases has decreased; and in 1990, keratoconus (33.1%) surpassed pseudophakic bullous keratopathy (24.1%) as the most common indication for penetrating keratoplasty. This decreasing incidence of pseudophakic bullous keratopathy may reflect the discontinued use of closed-looped anterior chamber and iris-plane intraocular lenses most commonly associated with this complication.

Molecular genetic analysis in autosomal dominant keratoconus.

Members in three generations of a family whose propositus had keratoconus were examined by biomicroscopy, with a corneoscope and a computer-assisted videophoto-keratoscope. Keratoconus was detected in eight of 15 family members with vertical transmission consistent with autosomal dominant inheritance. Affected individuals displayed variable topographic features. Abortive "nipple-type" cones were identified in some individuals in successive generations using the computer-assisted videophotokeratoscope and more advanced nipple-type cones detected on biomicroscopy of other family members. We selected a COL6A1 cDNA (the gene encoding the alpha 1 chain of type VI collagen) as a "candidate gene" to determine cosegregation with the disease locus. Linkage analysis excluded a gene locus for keratoconus on the most telomeric region of chromosome 21 in this family.

Disposable contact lenses.

Disposable soft contact lenses are an alternative to conventional extended-wear lenses and provide an acceptable margin of safety and convenience for the wearer. The lenses are worn for one to two weeks and then discarded. Buildup of tear film deposits is minimized, and the need for cleaning and disinfecting solutions is eliminated. The long-term safety of disposable contact lenses is unknown.

Penetrating keratoplasty 1981-1988: clinical indications and pathologic findings.

We analyzed 740 penetrating keratoplasty specimens received at the Intermountain Ocular Research Center from 1981 through 1988. These corneal specimens were categorized by clinical indications for removal and pathologic confirmation of the clinical findings. Keratoconus was the most common indication for a penetrating keratoplasty (22.8%). This was closely followed by pseudophakie bullous keratopathy (21.8%), regraft (13.2%), scarring (8.9%), aphakic bullous keratopathy (6.4%), and Fuchs' endothelial dystrophy (5.8%). Since 1984, pseudophakic bullous keratopathy has surpassed keratoconus as the most common indication for penetrating keratoplasty (27.3% vs. 20.2%). Pseudophakic bullous keratopathy was found more commonly than keratoconus in each of the last four years of this study. The most common type of intraocular lens associated with pseudophakic bullous keratopathy was an anterior chamber lens (52.8%), with iris-fixated (26.7%) and posterior chamber (17.4%) lenses seen less frequently.

Late complications of combined radial and transverse keratotomy after penetrating keratoplasty associated with atopic keratoconjunctivitis.

A 31-year-old man underwent bilateral penetrating keratoplasties for keratoconus. He had intolerable anisometropia postoperatively, with high irregular myopic astigmatism in the left eye. He could not wear contact lenses. A combined radial keratotomy and transverse keratotomy were performed, resulting in improved visual acuity. One year post-operatively he developed rapid vascularization of two of the radial incisions. This was associated with an acute allograft rejection, graft failure, and progressive changes in corneal topography.

Lack of ocular changes with dimethyl sulfoxide therapy of scleroderma.

Eighty-four patients with scleroderma hand ulcers were treated 3 times daily for 3 months in a randomized, double-blind clinical trial by immersing their hands into bags of topical 70% dimethyl sulfoxide (DMSO), topical 2% DMSO, or 0.85% normal saline. Fifty-five of the patients completed the study, 46 of whom received blinded initial (0 days) and final (12 weeks) full ophthalmologic examinations. This evaluation included past ocular history, past drug history, family ocular history, pupillary examination, cycloplegic refraction, motility study, applanation tension, indirect dilated funduscopic examination, and slit-lamp examination. No statistical difference in these ocular variables, including visual acuity, lenticular changes, and cataract development, were noted among the three groups, and in no patients were the DMSO-related lenticular changes reported in numerous animal studies found. The maximum theoretical dosage of DMSO administered was 2.6 g/kg/day, which is comparable to those used in the animal studies.

Cytologic diagnosis of acanthamoebic keratitis.

A case of acanthamoebic keratitis was identified from a corneal scraping stained with a modified Papanicolaou stain. The characteristic double-walled cyst forms were easily identified. Corneal scraping cytology provides a rapid, noninvasive means of diagnosis and follow-up for this serious disease.

Contact lens care and complications.

In the past 20 years, great strides have been made in contact lens technology, but this progress has been accompanied by a multitude of lens-related problems. Bacterial keratitis may be the most significant problem, but reports of Acanthamoeba keratitis, a parasitic corneal infection, are increasing. Infectious complications may be lessened by proper lens care. Thermal disinfection is recommended for soft lenses with a low water content; chemical decontamination is preferred for soft contact lenses with a high water content.

What patients should know about radial keratotomy.

Radial keratotomy is a relatively new, widely advertised procedure that promises patients with myopia 20/20 vision without corrective lenses. However, radial keratotomy sometimes does not fulfill this promise. New studies have reported numerous cases in which patients were not helped or were actually harmed by radial keratotomy. Also, its long-term effects are unknown. Family physicians should advise patients to approach the procedure with caution.

Relaxing incisions. Corneal topography.

The topography of circumferential corneal relaxing incisions in eye bank eyes was studied using the corneascope. Significant flattening in the meridian perpendicular to the corneal relaxing incision was found with steepening 90 degrees away in a ratio of two diopters of flattening to one diopter of steepening. This study demonstrates the range of change in corneal astigmatism from 0.58 D for a single one clock hour incision to 5.93 D for a unilateral three clock hour incision. This is compared to symmetrical relaxing incisions placed 180 degrees apart which produce 0.78 D of astigmatic change for one clock hour incisions, and 13.97 D of change for symmetrical three clock hour incisions. The larger shifts in corneal power were also associated with a small degree of central corneal flattening or decreased corneal power.

Acquired retraction syndrome associated with orbital metastasis.

A patient with metastatic disease of the lateral orbit developed an acquired motility defect similar to Duane's retraction syndrome. An acquired retraction syndrome, unlike the congenital form, is due either to mechanical defects of the orbit and eye or to neurologic disease. The direction of gaze in which the retraction occurs is the clinical clue to the location of the restricting element in the mechanically caused cases.