Torulopsis glabrata endophthalmitis after keratoplasty with an organ-cultured cornea.

Fungal endophthalmitis developed in an elderly woman following penetrating keratoplasty with an organ-cultured cornea. An unsuccessful search was made for the source of the infection. Modification in our sterility checks prior to surgery were made in hopes of preventing future infections.

Organ-cultured corneal endothelium in vivo.

We used the clinical specular microscope to examine the endothelium of 14 clear penetrating corneal grafts that ranged from 4 days to 2 1/2 years posttransplantation. All the donor corneas had been preserved in organ culture at 37 C for up to five weeks before grafting. Ten of the transplants were aphakic. The graft endothelial cell density, although less than that of normal corneas of the same age, was similar to that of other transplants done by the same two surgeons using alternate methods of donor preservation. We found a significant inverse correlation between graft endothelial cell density and the age of the corneal donor.

Paired arcuate keratotomy. A surgical approach to mixed and myopic astigmatism.

Twenty-five cadaver eyes were used to study the effect of paired arcuate keratotomy on corneal astigmatic changes. Paired arcuate incisions placed at optical zones of 5, 6, 7, 8, and 9 mm were progressively lengthened from 45 degrees to 60 degrees, 90 degrees, and, finally, 120 degrees. The corneal flattening in the meridian centered over the incisions and the corneal steepening 90 degrees away were quantified with each successive lengthening. Linear regression analysis showed a direct linear relationship of corneal astigmatic change (sum of corneal flattening and steepening, or delta K) to decreasing optical zone size as measured in millimeters and increasing incision length as measured in degrees. The delta K value ranged from 2.65 +/- 1.07 diopters to 22.05 +/- 3.55 D. The flattening/steepening coupling ratio mean was 1.47 +/- 0.41. Progressively longer paired arcuate incisions produced a predictable and titratable corneal flattening in the meridian centered over the incisions and a slightly smaller corneal steepening 90 degrees away, making the procedure ideal for mixed astigmatism.

Contrast sensitivity and reading through multifocal intraocular lenses.

Multifocal intraocular lenses are intended to increase depth of focus for patients with cataracts, but optical considerations predict reduced retinal-image contrast. We evaluated visual performance through multifocal intraocular lenses by measuring contrast sensitivity functions and reading speed for age-matched groups with multifocal and monofocal intraocular lenses and two normal control groups. Contrast sensitivity functions of the patients with multifocal lenses did not differ significantly for optical distances differing by 2.5 diopters, indicating substantial depth of focus. Normal and monofocal contrast sensitivity functions were nearly identical, and both were about a factor of two higher than multifocal contrast sensitivity functions. Patients with multifocal lenses showed deficits in reading speed only for low-contrast text (less than 30%) and small letters (0.2 degree and 1.0 degree).

Fungal contamination in organ culture.

Fungal contamination of organ-cultured corneas was studied retrospectively. Over a 3 1/2-year period, 5.2% of 696 corneas became contaminated by fungi in organ culture. The average length of time for fungal contamination to occur in organ culture was 11 days. The most frequent contaminating fungi were those of the Candida species. In addition to previously identified risk factors for donor cornea contamination, those corneas from donors given mechanical respiratory assistance at the time of death, those corneas with long postmortem times, and those corneas with positive postwash cultures were identified as being at higher risk for fungal contamination in organ culture.

McCarey-Kaufman (MK) organ culture and MK medium-shifted corneas.

Paired human donor corneas were studied to determine the effects of temperature, osmolarity, and media shifts on the endothelium of corneas stored in McCarey-Kaufman (MK) medium initially and then shifted to standard organ culture medium. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) demonstrated intact corneal endothelium in six of seven human control corneas stored in MK medium prior to fixation. Intact corneal endothelium was similarly demonstrated by specular microscopy, SEM, and TEM in seven of seven "MK-shifted" corneas. These data suggest that MK-stored donor corneas may be transferred into an organ culture system at 34 degrees C for prolonged storage with maintenance of corneal endothelial cell viability.

Trapezoidal astigmatic keratotomy. Quantification in human cadaver eyes.

The mechanism by which surgical procedures correct astigmatism are incompletely understood and, therefore, the results are often unpredictable. In this study, a Terry keratometer was used to analyze the effect of each component part of a 3-, 4-, and 5-mm trapezoidal astigmatic keratotomy. Semiradial incisions along the horizontal meridian produced corneal flattening along the horizontal meridian twice that of the vertical meridian, therefore inducing positive cylinder astigmatism at 90 degrees. A single pair of tangential incisions placed 5 mm apart, when added to the semiradial incisions, accounted for 100%, 87%, and 78% of the maximal effect from the 3-, 4-, and 5-mm completed trapezoidal astigmatic keratotomies, respectively. This study suggests that maximal correction of astigmatism may be attained with a single set of tangential incisions placed 5 mm apart between two sets of semiradial incisions.

Human corneal endothelial layer repair during organ culture.

Circular freeze-thaw endothelial wounds were created on paired human corneas. Ultrastructural and physiological studies were performed after organ culture (OC) incubation at 37 C from 1 to 21 days as well as on fresh noncultured controls. As early as 24 hours after injury, OC corneas demonstrated ultrastructurally intact endothelial cells at the margin of the wound, elongating and sliding toward its center. All OC corneas were completely covered by ultrastructurally intact and physiologically functioning endothelial cells by seven days of OC. These cells were approximately twice normal size. Enlarged endothelial cells that maintained deturgescence function were seen in the wounded area after 14 and 21 days of OC. None of the fresh controls demonstrated deturgescence function and in none could ultrastructurally intact endothelial cells be found in the area of the wound. This confirms our hypothesis that during 37 C OC incubation, human corneal endothelium repairs defects in its layer by cells that are physiologically and ultrastructurally intact.

Psychosocial characteristics of candidates for the prospective evaluation of radial keratotomy (PERK) study.

The National Eye Institute Prospective Evaluation of Radial Keratotomy (PERK) Study is a multicenter clinical trial for the evaluation of radial keratotomy. This article describes the questionnaire data collected on PERK patients and compares them with a similar group of myopic persons studied during the Rand Health Insurance Experiment (heretofore referred to as the Rand study). The PERK patients are young, white myopes who dislike being dependent on corrective lenses but perceive themselves to be more visually impaired than do comparable Rand study myopes. Most female subjects and a plurality of the male subjects have tried contact lenses and quit wearing them mainly because use of the lenses was inconvenient or bothersome. There is no evidence that patients are psychologically or socially deviant. Both male and female subjects expressed a fear of being without vision and cited impatience with the lenses as their major motivation for wanting surgery.

Clinical use of the 193-nm excimer laser in the treatment of corneal scars.

Phototherapeutic keratectomy using a 193-nm excimer laser was performed at four centers on 33 sighted patients with corneal opacity and/or irregular astigmatism. Pathologic conditions included anterior stromal and superficial scarring from postinfectious and posttraumatic causes, including inactive herpes simplex virus, anterior corneal dystrophies, recurrent erosions, granular dystrophy, and band keratopathy. Most patients received peribulbar anesthesia and underwent removal of the epithelium prior to laser ablation. A majority of patients had a reduction in the amount of corneal scarring and approximately half had improved visual acuity. No intraocular reaction or changes in endothelial counts were seen, and some patients avoided the need for penetrating keratoplasty. Reepithelialization usually occurred within 4 or 5 days and we noted no significant scarring secondary to use of the laser. It was difficult to eliminate preexisting irregular astigmatism despite the use of surface modulators, such as methylcellulose. A hyperopic shift secondary to corneal flattening was encountered in approximately 50% of the patients. A combination of myopic ablation, followed immediately by a secondary hyperopic steepening, may minimize this refractive change. The 193-nm excimer laser is an effective new tool in the treatment of selected patients with superficial corneal opacity from a variety of conditions.

Phase contrast microscopy. Diagnosis of ghost cell glaucoma following cataract extraction.

Ghost cell glaucoma may be suspected when intraocular pressure remains elevated following vitreous hemorrhage. Vitrectomy provides relief of the glaucoma and an improvement in vision. The vitrectomy specimen offers confirmation of the clinical diagnosis when examined by phase contrast microscopy.

Phacoemulsification and modern cataract surgery.

The techniques and results of cataract surgery have changed dramatically during the past three decades. In the USA, we have moved from intracapsular cataract extraction as the preferred technique to almost exclusively extracapsular techniques. Smaller incisions have become the standard, with phacoemulsification now being the method of choice for most surgeons. Along with these advances have come improved intraocular lens materials and designs, especially well suited for use with smaller incisions. Phacoemulsification as a method to remove the cataractous lens was first proposed more than 20 years ago. Advances in techniques and equipment have led to a dramatic increase in the popularity of phacoemulsification with increased safety and efficiency. Viscoelastic agents have been developed synchronously with modern phacoemulsification techniques, playing an integral role in the success of this new technology. Improved surgical techniques for removing the anterior lens capsule have decreased the incidence of both intraoperative and postoperative capsular complications. Nucleus removal, formerly performed primarily in the anterior chamber, is now performed in the posterior chamber, decreasing damage to the corneal endothelium. Improved wound construction allows many wounds to be left unsutured, and smaller wounds allow shorter recovery time and greater intraoperative control and safety. Intraocular lenses can have smaller optic sizes and still maintain accurate centration. Foldable intraocular lenses can take advantage of the smaller incision, even further shortening the time to visual recovery. Continual evolution of this technology promises to further improve patient outcomes after cataract surgery.

Unsuspected infectious keratitis in host corneal buttons.

Infectious keratitis may be unsuspected preoperatively in patients undergoing penetrating keratoplasty. We have diagnosed five cases of previously unknown corneal infection discovered only after post-keratoplasty histopathologic examination using specific stains. These cases of preoperatively unsuspected infectious keratitis illustrate examples where histopathologic examination using specialized stains may alert the physician to the need for appropriate postoperative antimicrobial therapy. Furthermore, these cases illustrate the ability of soft contact lenses to mask symptoms of infectious keratitis. Additionally, the clinical appearance of advanced bullous keratopathy may mask signs of infectious keratitis.

The surgical management of overcorrection in myopic epikeratophakia.

Three patients underwent myopic epikeratophakia that resulted in overcorrection. The surgical management of these cases involved resuturing the myopic lenticule to flatten the peripheral curvature and reduce the amount of minus power. A reduction in the overcorrection was achieved in all cases.

Endothelial cell survival on transplanted human corneas preserved by organ culture with 1.35% chondroitin sulfate.

We transplanted 30 donor corneas preserved at 34 C for 15 to 33 days in culture medium containing 1.35% chondroitin sulfate and compared them with 30 corneas transplanted during the same period, but preserved only in McCarey-Kaufman medium at 4 C for one to 81 hours. Two months after keratoplasty there was no statistically significant difference in central endothelial cell loss between the organ-cultured grafts and those preserved in McCarey-Kaufman medium (9% vs 7% cell loss, respectively). The study detected with 90% power a difference in cell loss of approximately 10% or more. On the first postoperative day, the organ-cultured grafts were thicker than those grafts preserved in McCarey-Kaufman medium, and the thickest corneas were those cultured for the longest times. The corneal thickness was similar in the two groups after three weeks. These results demonstrated that donor corneal endothelial cells preserved for up to one month at 34 C in 1.35% chondroitin sulfate appear to survive and function after keratoplasty as well as those preserved at 4 C for one to three days in McCarey-Kaufman medium.

Retinal detachment after neodymium:YAG laser posterior capsulotomy.

We reviewed the records of 397 patients who had undergone Nd:YAG laser posterior capsulotomy between July 1983 and August 1988. Of the 366 eyes that had been followed up for three months or more, 13 (3.6%) developed a retinal detachment after capsulotomy; of these 13 detachments, 11 (84.6%) occurred within the first year. The combination of male gender with axial myopia (greater than or equal to 25.00 mm), a history of lattice degeneration, or a history of retinal detachment in the fellow eye was a significant risk factor for the development of retinal detachment after YAG capsulotomy.

Anatomic study of transsclerally sutured intraocular lens implantation.

We used 21 cadaver eyes to study transsclerally sutured, ciliary sulcus-fixated intraocular lens implantation. Results showed that transscleral sutures should exit the sclera less than 1 mm posterior to the corneoscleral limbus for true ciliary sulcus fixation. The relationship of the ciliary sulcus to the overlying posterior surgical limbus differed in the vertical and horizontal meridians; needles that pierced the ciliary sulcus after being passed perpendicularly through the sclera entered the sclera 0.83 +/- 0.1 mm posterior to the posterior surgical limbus in the vertical meridians and 0.46 +/- 0.1 mm in the horizontal meridians. The major arterial circle of the iris (located in the ciliary body) was avoided as was the entire ciliary body during proper ciliary sulcus fixation. A one-piece, all polymethylmethacrylate, 10-degree vaulted, 13.5-mm haptic spread intraocular lens provides excellent optic centration and haptic stabilization when the haptic structure is placed at the greatest haptic spread and one transscleral suture pass per haptic is made.

A metabolic and electron microscopic study of human organ-cultured cornea.

We examined the glucose metabolism and ultrastructure of human corneas stored for 11 to 37 days in organ culture using a modified Eagle's minimum essential medium. Changing the media twice weekly provided a stable pH of 7.22 to 7.28 but the glucose concentration of the media decreased from 110 mg/100 ml to 30 mg/100 ml, and lactate concentration increased from 7 mg/100 ml to 84 mg/100 ml before media replacement. The initial rate of glucose uptake and lactate release averaged 149 mug/hr and 95 mug/hr, respectively, and the rates decreased approximately 50% by day 12. The glucose uptake rate stabilized between 40 and 60% of the original rate to day 37, but the lactate release rate decreased again at day 25 from 64 to 25%. The lactate/glucose ratio averaged 65 to 82% during the first 25 days of organ culture and 33 to 53% from days 28 to 37. Electron microscopy revealed that the endothelium formed a complete monolayer of normal appearing cells covering Descemet's membrane. Intracytoplasmic deposition of glycogen granules was present in endothelial, stromal, and epithelial cells.

Optisol corneal storage medium.

We compared the safety and efficacy of Optisol (Chiron Ophthalmics, Irvine, California), a new corneal storage medium, with McCarey-Kaufman and Dexsol corneal storage media (Chiron Ophthalmics, Irvine, California) and K-Sol corneal storage medium (Cilco, Huntington, West Virginia). Optisol contains dextran, 2.5% chondroitin sulfate, vitamins, and precursors of adenosine triphosphate (adenosine, inosine, and adenine). In in vitro studies, rabbit and human corneas stored in Optisol were thinner after 12 to 14 days at 4 C than tissue stored in other media. Thymidine uptake showed increased mitotic activity in human corneal endothelial cells cultured in Optisol, compared to Dexsol. Specular microscopic fields showed larger are-as of visibly intact endothelial cells and ultrastructural examination disclosed fewer structural changes in endothelial cells stored in Optisol, compared to tissue stored in Dexsol. In vivo, no clinical signs of epithelial toxicity or histologic evidence of intraocular inflammation were observed in rabbit eyes in which Optisol drops were instilled four times a day for 14 days. Finally, 51 patients undergoing penetrating keratoplasty with tissue stored in Optisol for one to six days (mean, 3.6 days) were enrolled in an uncontrolled, open-label clinical study. The percentage of clear grafts (93%, 41 of 44 patients examined at three months; and 98%, 42 of 43 patients examined at six months) and endothelial cell loss (5.0% and 11.5% at three and six months, respectively) were comparable to data from previous studies that used tissue stored in other short-term and intermediate-term media. The results suggest that Optisol storage preserves corneal endothelial cells for up to two weeks at 4 C, thereby permitting flexibility in the use of donor tissue for corneal transplantation, and that Optisol storage yields thinner tissue, which may allow for more accurate evaluation and more effective surgical manipulation.

Results one year after using the 193-nm excimer laser for photorefractive keratectomy in mild to moderate myopia.

As part of a clinical trial, photorefractive keratectomy using the VISX 2015 193-nm excimer laser was performed on 91 healthy eyes of 91 patients. Preoperative refractive errors (spherical equivalent) ranged from -1.00 to -7.50 diopters (mean, -4.16 +/- 1.41 diopters). No patient had more than 1 diopter of refractive astigmatism. Six months postoperatively, the average residual refractive error was +0.09 +/- 0.63 diopters (range, -2.13 to +1.63 diopters). Correction within 1 diopter of that attempted was attained in 85 eyes (93%). Uncorrected visual acuity of 20/40 or better was attained in 86 eyes (95%) and was 20/25 or better in 67 eyes (74%). At one year, follow-up information was available on 85 eyes of 85 patients. The average residual refractive error was -0.15 +/- 0.65 diopters (range, -2.50 to +1.63 diopters). Correction within 1 diopter of that attempted was attained in 85 eyes (93%). Uncorrected visual acuity was 20/40 or better in 83 eyes (98%) and was 20/25 or better in 68 eyes (80%). One patient lost three lines of best-corrected visual acuity because of corneal haze, dropping from 20/15 to 20/30, whereas all other patients returned to best-corrected visual acuity within one line of their preoperative best-corrected visual acuity. Photorefractive keratectomy with the 193-nm excimer laser appears to be a useful treatment modality for the reduction of mild to moderate myopia.