Effect of FK 506 on the cornea: use of topical FK 506 in corneal transplantation in a guinea pig-rat model.

To evaluate the effect of different concentrations 0.03%, 0.1% and 0.3% of FK 506 on xenograft corneal rejection, guinea pig corneas were transplanted into rats. FK 506 was then applied topically four times a day for 21 days. The grafts were inspected and scored according to opacity, edema, and graft protrusion. All grafts in the control group were rejected by the 14th postoperative day, and grafts in the FK 506 treated groups began to be rejected by the 17th postoperative day. Inflammatory cell infiltration was less dense in the FK 506 treated grafts than in the control group. Higher concentrations of FK 506 appeared to be more effective in preventing and decreasing the severity of the graft rejection. Topical FK 506 can delay the development of xenograft corneal rejection and decrease its severity in this animal model.

The effect of growth factor on antigen and viability of corneal endothelial cells.

The effect of epidermal growth factor (EGF) on corneal endothelial cell of rabbit, was evaluated. DNA synthesis of cultured corneal endothelial cells after adding EGF to culture medium and major histocompatibility (MHC) antigen expression of cornea preserved in EGF added Optisol were measured. EGF increased DNA synthesis of corneal endothelial cells at all concentrations tested (0.03 ng/ml-300 ng/ml) compared with control. The maximum increase of DNA synthesis was shown at the concentrations of 3.0-30 ng/ml. The effect of EGF on increase of DNA synthesis was more profound in second sub-cultured cells compared with first sub-cultured cells. In corneas preserved in Optisol for 3 days, 4 degrees C, class I antigen expression is decreased while class II antigen expression was slightly increased. In corneas preserved in EGF added Optisol for 3 days, 4 degrees C, class II antigen expression was more increased compared with those without EGF.

Near add power of the diffractive multifocal intraocular lens.

PURPOSE: To assess near visual acuity and patient satisfaction with the 3M diffractive multifocal intraocular lens (IOL). SETTING: Asan Medical Center, Ulsan University, Seoul, Korea. METHODS: Near acuity of 50 eyes implanted with the diffractive multifocal IOL was evaluated postoperatively. Near visual acuity was measured with best distance correction at 33 cm and then at each patient's preferred distance with an extra add of -0.25, +0.25, +0.50, or +0.75 D to the best distance correction. Mean follow-up was 11 months. RESULTS: All eyes obtained a near vision of J3 or better with the best distance correction and 34 (68.0%) obtained J1 or better. Extra add power increased near vision and was preferred in 44 eyes (88.0%) even though the reading distance was shortened. CONCLUSION: We recommend adding more than +3.5 D to the 3M multifocal IOL.

Expression of major histocompatibility complex antigen in Lewis rat cornea.

Fresh rat corneas as well as corneas preserved in several different corneal preservation media were stained with Avidin-Biotin-peroxidase Complex method in order to evaluate major histocompatibility complex (MHC) antigen expression. In fresh corneas, class I antigen was identified in corneal epithelium, stroma and endothelium. Class II antigen was identified only in stroma. In corneas preserved in the media which contained chondroitin and dextran for 7 days, class I antigen was somewhat decreased but class II antigen was increased. In corneas preserved in the medium which contained insulin or epidermal growth factor for 7 days, class II antigens seemed to be increased compaired to the fresh cornea. Expression of MHC antigens of corneas in the medium with fetal bovine serum were similar to those of fresh corneas.

Photoastigmatic refractive keratectomy in 168 eyes: six-month results.

Using a 193 nm excimer laser, we performed elliptical astigmatic and spherical corneal ablation on 168 eyes with compound myopic astigmatism and analyzed the three- and six-month postoperative results. Mean preoperative astigmatism was 1.51 +/- 0.81 diopters (D). Mean three- and six-month postoperative astigmatism was 0.70 +/- 0.58 D and 0.67 +/- 0.60 D, respectively. Six months after surgery, eyes with less than 1.00 D preoperative astigmatism improved 4.8%. The improvement was 53.5% and 59.1% for eyes with a preoperative astigmatism of 1.00 D to 2.00 D and above 3.00 D, respectively. Overall, astigmatism improved 55.6%. There was a wide distribution from overcorrection to undercorrection. Astigmatism six months after surgery was within 10 degrees of the preoperative axis in 46.1% of eyes.

Heterologous corneal endothelial cell transplantation--human corneal endothelial cell transplantation in Lewis rats.

A heterologous corneal endothelial transplantation was attempted using human endothelial cells and a Lewis rat penetrating keratoplasty model. Cultured human endothelial cells were seeded to a Lewis rat cornea, which was denuded of its endothelium. When grafted into the syngeneic Lewis rat, the graft remained clear for at least five days, and then became opaque and edematous because of immune rejection reaction. In contrast, corneas denuded of their endothelium became opaque and edematous immediately after transplantation. These results demonstrate that transplanted endothelial cells have enough antigens to induce rejection reaction even though they have the functional capacity to deturge the cornea.

Plasmacytoma presented as a lid mass--a case report.

A solitary lid mass was identified as a primary solitary plasmacytoma. A 71 year old male presented with a left upper lid mass. The mass was found to be firmly intermingled with the underlying tarsal plate. A total excision was successfully performed and the lid margin was reconstructed with a good cosmetic result. There were no positive findings in the systemic work-up. The light microscopic findings suggest that the mass is of tarsal plate origin. It is the first case of plasmacytoma of tarsal plate origin presented as a lid mass.

Experimental orthotopic penetrating keratoplasty--a rat penetrating keratoplasty model.

An orthotopic penetrating keratoplasty model was developed in the rat. An oversized (0.5 mm) graft was used and 8 interrupted sutures were applied. These sutures were not removed. Eleven grafts out of 13 were rejected by the 3rd week in the disparate group (Brown Norway rat to Lewis rat transplantation group), which was characterized by edema, opacity, and neovascularization. All grafts remained clear in the syngeneic group (Lewis rat to Lewis rat transplantation group). Immunohistochemical examination was performed. This model seems to be a reliable and reproducible one to evaluate rejection reaction in corneal transplantation.

Non-contact tonometry: an ideal method for mass screening.

We evaluated one of the new non-contact tonometers, the Pulsair non-contact tonometer, to assess its accuracy and reliability. Measurements on 101 eyes were used to assess its accuracy against Goldmann tonometry measurements, and another 24 eyes were used to assess its reliability (reproducibility). The results showed the instrument to be highly accurate and reliable in measurement.

Lysis of vitreous strands with neodymium: YAG laser.

Eighteen eyes with vitreous strands adherent to the corneoscleral wounds of previous cataract surgery were treated with neodymium: YAG laser to lyse those strands. Twelve eyes were treated for management of cystoid macular edema (CME group); six eyes were treated for prophylaxis of possible CME (prophylactic group). In the CME group, visual acuity improved two or more lines in nine eyes (75.0%), and seven eyes had a post laser visual acuity of 0.5 or better (One eye had a pre-treatment visual acuity of 0.5 or better). In the prophylactic group, visual acuity was either maintained at the pre-treatment visual acuity of 0.5 or better. In the prophylactic group, visual acuity was either maintained at the pre-treatment level or improved in five eyes (83.3%) 18 months later following laser treatment. This procedure was complicated by retinal detachment in one case and the elevation of intraocular pressure over 10 mmHg in another case.

Measurement of IgA level in normal human tears by enzyme-linked immunosorbent assay.

The advantages of the enzyme-linked immunosorbent assay (ELISA) are its sensitivity and its accuracy in detecting and measuring immunoglobulin classes. By ELISA, the tear IgA level was measured in 165 healthy persons. Tears were collected by a strong absorbent (Weck Cel). This is the first report of a tear IgA level in normal Koreans measured by ELISA. The mean level was 60.5 +/- 23.4 mg/dl. There was no statistically significant difference between the IgA level in the males (61.8 +/- 23.2 mg/dl) and that of the females (58.4 +/- 23.5 mg/dl)(p greater than 0.05). The difference between the tear IgA levels in the various age groups was not significant (p greater than 0.05).

Intraocular lens implantation in phakic rabbit eyes.

Three sizes (13.5 mm, 17.5 mm, and 18.5 mm) of open loop, one piece, poly(methyl methacrylate) anterior chamber intraocular lenses (IOLs) were implanted in 12 phakic rabbit eyes to evaluate the effect of the IOL on the crystalline lens and the anterior chamber. Six eyes were used as a control group. Minimum follow-up was four weeks. All the IOLs touched the crystalline lenses, and on the first postoperative day, round subcapsular lens opacities were found in all eyes in the area of IOL contact. The lens opacities became more dense with time. Only one eye in the control group showed a subcapsular opacity, which was linear rather than round. Anterior chamber inflammation was 1+ to 2+ in ten eyes (80%) in the IOL group during the first and second weeks, whereas minimal inflammatory changes occurred in the control group. These results suggest that with current IOL technology, IOL insertion in the phakic eye to correct refractive errors results in a high incidence of cataract if IOL-to-lens touch occurs.

Neodymium: YAG laser vitreolysis for treatment and prophylaxis of cystoid macular oedema.

Eighteen eyes with vitreous strands adherent to the corneoscleral wound of previous cataract surgery were treated with neodymium: YAG laser to achieve vitreolysis. Twelve eyes were treated for management of cystoid macular oedema (CMO group) and six eyes were treated for prophylaxis of possible CMO (prophylactic group). In the CMO group, visual acuity improved two or more Snellen lines in 10 eyes (83.3%) and seven eyes had a post-laser visual acuity of 20/40 or better (one eye had a pre-treatment visual acuity of 20/40 or better). In the prophylactic group, visual acuity was either maintained at the pre-treatment level or improved in five eyes (83.3%) eighteen months after laser treatment. This procedure was complicated by retinal detachment in one case and elevation of intraocular pressure over 10 mmHg in another case.

Neodymium:YAG laser zonulysis for treatment of lens subluxation.

Nine eyes with lens subluxation in seven patients (6 patients with Marfan's syndrome, 1 with idiopathic lens subluxation) were treated by neodymium:YAG (Nd:YAG) laser zonulysis. The procedure uses an Nd:YAG laser to lyse the zonules to obtain a clear aphakic visual axis. Pretreatment best-corrected visual acuity was 20/60 or worse in eight eyes (6 eyes less than or equal to 20/200). Movement of the crystalline lens was achieved after zonulysis in all cases (100%), and a clear aphakic visual axis, sufficient to maintain aphakic correction without diplopia or glare, was obtained in eight eyes (88.9%). The procedure was combined with optical iridotomy in three cases (33.3%). Five cases (55.6%) required more than one zonulysis treatment. Visual acuity improved two or more Snellen lines in all but one eye (7 eyes greater than or equal to 20/60). Four cases had complications which included: increased intraocular pressure (IOP), mild iritis, recurrent migration of the lens into the visual axis, and crystalline lens damage. The final two complications necessitated eventual surgical removal of the lens. These results suggest that Nd:YAG laser zonulysis may be of benefit as an alternative treatment modality for selected patients with lens subluxation.

Human cadaver corneal thinning for experimental refractive surgery.

Human cadaver eyes can be dehydrated by prolonged elevation of intraocular pressure (three to five hours) or by hyperosmotic Dextran over a 20- to 30-minute period. We divided four pairs of donor eyes into two groups (A and B) and dehydrated four corneas by each method. After corneal thinning to 500 to 600 microns, central corneal pachymetry was measured every ten minutes during the rehydration period for one hour, with each cornea pair being moistened at a different rate (every 30 seconds, 1 minute, 2.5 minutes or 5 minutes). The resultant increase in central corneal thickness noted by change in pachymetry (delta P) ranged from 12.4% to 14.7% over one hour between the two groups. delta P did not differ significantly between groups A and B, regardless of the varying rate of balanced salt solution irrigation of the corneas. Thus, it appears that either method of corneal dehydration provides comparable stability of corneal thinning for at least one hour to allow consistent corneal dynamics for experimental refractive surgery.

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.