Long-term follow-up results of lamellar keratoplasty as a treatment for recurrent pterygium and for scleral necrosis induced by beta-irradiation.

PURPOSE: To evaluate the efficacy and safety of lamellar keratoplasty (LK) in the treatment of recurrent pterygium and of scleral necrosis induced by beta-irradiation. METHODS: A retrospective review of patients who, between 1988 and 2001, underwent LK for the above indications. Recurrence rates, tectonic outcomes, pre- and postoperative visual acuities, and complications were analyzed. RESULTS: In the recurrent pterygium group, LK was performed on 68 eyes. The mean age (mean +/- SD) at presentation was 45.1 +/- 13.7 years (range 17 to 77). The recurrence rate following LK was 5.9%, with a mean time to recurrence of 6.2 +/- 2.9 months (range 3 to 10). In all cases, the recurrence occurred above or below the lamellar grafts, and a second LK prevented any further recurrence. The mean length of follow-up was 27.1 +/- 26.6 months (range 3 to 132). The best-corrected visual acuity (BCVA) improved or remained unchanged in 65 of the 68 eyes (95.6%) but was reduced in the remaining three eyes (4.4%). In the scleral radionecrosis group, LK was performed on 30 eyes. The mean age at presentation was 67.7 +/- 10.3 years (range 37 to 85). Tectonic restoration was achieved in all patients. The mean length of follow-up was 49.0 +/- 45.1 months (range 8 to 120). The BCVA improved or remained unchanged in all patients. No significant complications were identified. CONCLUSION: Lamellar keratoplasty is a safe and effective treatment option for both recurrent pterygium and beta-irradiation-induced scleral necrosis. In our opinion, LK is the treatment of choice for multiple or aggressive recurrences of pterygium and a successful management option for scleral radionecrosis.

Long-term results of corneal wedge excision for pellucid marginal degeneration.

PURPOSE: A retrospective study reporting long-term visual and astigmatic results of patients with pellucid marginal degeneration (PMD) treated by corneal wedge excision. METHODS: The notes of 9 patients (10 eyes) treated by corneal wedge excision were reviewed. All patients had typical PMD and were treated by excision of an inferior crescent of diseased corneal tissue. The excised area measured approximately 2 mm in width and extended from the 4 o'clock to the 8 o'clock meridian. All thinned corneal tissue was removed. Normal-thickness corneal stroma was then reapposed with 10/0 nylon or 10/0 polypropylene sutures. Post-operative selective suture removal was performed until a satisfactory visual and astigmatic result was achieved. This was guided by refraction, keratometry and photo-keratoscopy results. Pre-operative best corrected visual acuity ranged from 6/12 to 6/60 with an associated mean keratometric astigmatism of +13.8 dioptres (range 8-25 dioptres, axis range 30 degrees-175 degrees). Mean follow-up was 59 months (range 14-138 months). RESULTS: Post-operatively a stable corrected visual acuity of 6/9 or better was achieved in all cases in a mean time of 5.4 months (range 3-12 months). Mean post-operative keratometric astigmatism was 1.4 dioptres (range 0.5-4 dioptres). Over the course of follow-up long-term astigmatic drift (LTAD) was noted, mean 2.1 dioptres (range 0.5-5.5 dioptres). Three patients developed mild inferior pannus related to peripherally sited sutures. One case developed apparent corneal hydrops within the corneal wound after 9 years of follow-up. CONCLUSIONS: We believe that corneal wedge excision offers an excellent surgical result for patients with PMD, although modification of the technique may be required to improve long-term astigmatic drift.

Excimer phototherapeutic keratectomy for recurrent granular dystrophy.

PURPOSE: Corneal grafting is a standard treatment for visually disabling granular dystrophy. The visual results of this procedure are generally good, but can be marred by recurrences of granular deposits some years later. We report the results of phototherapeutic keratectomy (PTK) for recurrent granular dystrophy in three eyes from two patients and discuss the possibilities of treating de novo granular dystrophy with excimer laser. METHODS: The records of two patients (three eyes) treated with excimer PTK for recurrent granular deposits on the donor cornea were reviewed. RESULTS: In all cases visual acuity was improved and repeat corneal grafting avoided. No significant complications occurred although one eye had further recurrence of granular deposits which was also successfully retreated with excimer PTK. Follow-up on these cases varies between five months and three years. CONCLUSIONS: We believe that excimer PTK offers a simple, safe and repeatable way of restoring visual acuity to most cases of recurrent granular dystrophy. Visual recovery is fast and all the incumbent problems of repeat grafting are avoided.

Phospholamban expressed in slow-twitch and chronically stimulated fast-twitch muscles minimally affects calcium affinity of sarcoplasmic reticulum Ca(2+)-ATPase.

Chronic excitation, at 2 Hz for 6-7 weeks, of the predominantly fast-twitch canine latissimus dorsi muscle promoted the expression of phospholamban, a protein found in sarcoplasmic reticulum (SR) from slow-twitch and cardiac muscle but not in fast-twitch muscle. At the same time that phospholamban was expressed, there was a switch from the fast-twitch (SERCA1) to the slow-twitch (SERCA2a) Ca(2+)-ATPase isoform. Antibodies against Ca(2+)-ATPase (SERCA2a) and phospholamban were used to assess the relative amounts of the slow-twitch/cardiac isoform of the Ca(2+)-ATPase and phospholamban, which were found to be virtually the same in SR vesicles from the slow-twitch muscle, vastus intermedius; cardiac muscle; and the chronically stimulated fast-twitch muscle, latissimus dorsi. The phospholamban monoclonal antibody 2D12 was added to SR vesicles to evaluate the regulatory effect of phospholamban on calcium uptake. The antibody produced a strong stimulation of calcium uptake into cardiac SR vesicles, by increasing the apparent affinity of the Ca2+ pump for calcium by 2.8-fold. In the SR from the conditioned latissimus dorsi, however, the phospholamban antibody produced only a marginal effect on Ca2+ pump calcium affinity. These different effects of phospholamban on calcium uptake suggest that phospholamban is not tightly coupled to the Ca(2+)-ATPase in SR vesicles from slow-twitch muscles and that phospholamban may have some other function in slow-twitch and chronically stimulated fast-twitch muscle.

Analysis of excitation-contraction-coupling components in chronically stimulated canine skeletal muscle.

The chronic stimulation of predominantly fast-twitch mammalian skeletal muscle causes a transformation to physiological characteristics of slow-twitch skeletal muscle. Here, we report the effects of chronic stimulation on the protein components of the sarcoplasmic reticulum and transverse tubular membranes which are directly involved in excitation-contraction coupling. Comparison of protein composition of microsomal fractions from control and chronically stimulated muscle was performed by immunoblot analysis and also by staining with Coomassie blue or the cationic carbocyanine dye Stains-all. Consistent with previous experiments, a greatly reduced density was observed for the fast-twitch isozyme of Ca(2+)-ATPase, while the expression of the slow-twitch Ca(2+)-ATPase was found to be greatly enhanced. Components of the sarcolemma (Na+/K(+)-ATPase, dystrophin-glycoprotein complex) and the free sarcoplasmic reticulum (Ca(2+)-binding protein sarcalumenin and a 53-kDa glycoprotein) were not affected by chronic stimulation. The relative abundance of calsequestrin was slightly reduced in transformed skeletal muscle. However, the expression of the ryanodine receptor/Ca(Ca2+)-release channel from junctional sarcoplasmic reticulum and the transverse tubular dihydropyridine-sensitive Ca2+ channel, as well as two junctional sarcoplasmic reticulum proteins of 90 kDa and 94 kDa, was greatly suppressed in transformed muscle. Thus, the expression of the major protein components of the triad junction involved in excitation-contraction coupling is suppressed, while the expression of other muscle membrane proteins is not affected in chronically stimulated muscle.

Corneal graft survival: a retrospective Australian study.

Four hundred and forty-eight consecutive corneal grafts are analysed and their survival calculated using the actuarial life-table method. Overall survival at two years is 81 +/- 4% and at five years is 65 +/- 5%. Within diagnostic subgroups keratoconus has the best prognosis. Previous graft failure and recipient corneal vascularization are shown to have a negative effect on graft survival. Sex of patient, urgency of operation and use of combined procedures do not affect survival and second regrafts fare no worse than first regrafts. The use of the actuarial life-table method of analysing graft survival is discussed and its importance emphasized.