Cumulative sum analysis score and phacoemulsification competency learning curve

AIM

To use the cumulative sum analysis score (CUSUM) to construct objectively the learning curve of phacoemulsification competency.

METHODS

Three second-year residents and an experienced consultant were monitored for a series of 70 phacoemulsification cases each and had their series analysed by CUSUM regarding posterior capsule rupture (PCR) and best-corrected visual acuity. The acceptable rate for PCR was <5% (lower limit h) and the unacceptable rate was >10% (upper limit h). The acceptable rate for best-corrected visual acuity worse than 20/40 was <10% (lower limit h) and the unacceptable rate was >20% (upper limit h). The area between lower limit h and upper limit h is called the decision interval.

RESULTS

There was no statistically significant difference in the mean age, sex or cataract grades between groups. The first trainee achieved PCR CUSUM competency at his 22^nd case. His best-corrected visual acuity CUSUM was in the decision interval from his third case and stayed there until the end, never reaching competency. The second trainee achieved PCR CUSUM competency at his 39^th case. He could reach best-corrected visual acuity CUSUM competency at his 22^nd case. The third trainee achieved PCR CUSUM competency at his 41^st case. He reached best-corrected visual acuity CUSUM competency at his 14^th case.

CONCLUSION

The learning curve of competency in phacoemulsification is constructed by CUSUM and in average took 38 cases for each trainee to achieve it.

The UCP1 -3826A/G polymorphism is associated with diabetic retinopathy and increased UCP1 and MnSOD2 gene expression in human retina

PURPOSE

Uncoupling protein 1 (UCP1) reduces mitochondrial production of reactive oxygen species (ROS). ROS overproduction is related to diabetic retinopathy (DR), a chronic complication of diabetes mellitus (DM). Therefore, deleterious polymorphisms in the UCP1 gene are candidate risk factors for DR. We investigated the relationships between the UCP1 -3826A/G polymorphism and risk of DR and UCP1 gene expression in human retina. Considering that superoxide dismutase-2 (MnSOD2) enzyme is the first line of defense against oxidative stress in mitochondria, we also analyzed MnSOD2 gene expression in retinal samples according to different UCP1 -3826A/G genotypes.

METHODS

In a case-control study, frequencies of -3826A/G polymorphisms were analyzed in 257 type 1 DM patients (154 cases with DR and 103 controls without DR). In a cross-sectional study comprising cadaveric cornea donors, UCP1 and MnSOD2 gene expressions were evaluated in 107 retinal samples differentiated according to different -3826A/G genotypes.

RESULTS

In the type 1 DM group, multivariate analysis confirmed that the G/G genotype was an independent risk factor for DR (OR = 3.503; P = 0.043). In cornea donors, G allele carriers had higher UCP1 cDNA and protein concentrations than A/A carriers (P = 0.034 and P = 0.039, respectively). Interestingly, G allele carriers exhibited increased MnSOD2 expression (P = 0.001).

CONCLUSIONS

This study suggests that the -3826A/G polymorphism is associated with DR in type 1 DM patients. This is the first report demonstrating UCP1 gene expression in human retinas and indicates that the -3826A/G polymorphism influences its expression. In addition, the -3826G allele was associated with increased MnSOD2 expression; thus, suggesting that this allele could be a marker of oxidative stress.

The presence of the -866A/55Val/Ins haplotype in the uncoupling protein 2 (UCP2) gene is associated with decreased UCP2 gene expression in human retina

Uncoupling protein 2 (UCP2) is a mitochondrial transporter present in the inner membrane of mitochondria, and it uncouples substrate oxidation from ATP synthesis, thereby dissipating the membrane potential energy and consequently decreasing ATP production by mitochondrial respiratory chain. As a consequence of the uncoupling, UCP2 decreases the reactive oxygen species (ROS) formation by mitochondria. ROS overproduction is related to diabetic retinopathy (DR), a chronic complication of diabetes mellitus (DM). Recently, our group reported that the -866A/55Val/Ins haplotype (-866G/A, Ala55Val and Ins/Del polymorphisms) of the UCP2 gene was associated with increased risk for DR in patients with DM. The purpose of this study was to analyze the effect of this haplotype on UCP2 gene expression in human retina. In addition, MnSOD2 gene expression was also investigated according to different UCP2 haplotypes. This cross-sectional study included 188 cadaveric cornea donors. In a subset of 91 retinal samples differentiated according to the presence of the mutated UCP2 haplotype and risk alleles of the -866G/A and Ins/Del polymorphisms, UCP2 and MnSOD2 gene expressions were measured by semi-quantitative RT-qPCR. Mutated UCP2 haplotype carriers (homozygous + heterozygous) had a lower UCP2 gene expression than reference haplotype carriers (8.4 ± 7.6 vs. 18.8 ± 23.7 arbitrary units; P = 0.046). Accordingly, UCP2 gene expression was decreased in -866A carriers when compared with G/G carriers (P = 0.010). UCP2 gene expression did not differ between Ins allele carriers and Del/Del carriers (P = 0.556). Interestingly, subjects carrying the heterozygous UCP2 haplotype showed increased MnSOD2 gene expression (P = 0.025). This is the first report suggesting that the presence of the -866A/55Val/Ins haplotype is associated with decreased UCP2 gene expression in human retina. Possibly, MnSOD2 expression might influence the UCP2 effect in the protection against oxidative stress.

Influence of Final Corneal Thickness in Visual Acuity After Deep Lamellar Endothelial Keratoplasty

PURPOSE

To determine if the final corneal thickness after deep lamellar endothelial keratoplasty (DLEK) is correlated in any way with visual performance.

METHODS

One hundred fifty-five consecutive eyes without macular disease underwent DLEK surgery and had pachymetry recorded at 6 months postoperatively. The eyes were grouped according to visual acuity, and pachymetry was correlated between groups: group 1 (20/20, 20/25, or 20/30), n = 38; group 2 (20/40 or 20/50), n = 79; group 3 (20/60, 20/70, or 20/80), n = 30; group 4 (20/100 or worse), n = 8.

RESULTS

The mean pachymetry, SD, and range of pachymetry for each group are as follows: group 1, 0.571 +/- 0.080 mm (range, 0.408-0.784 mm); group 2, 0.598 +/- 0.080 mm (range, 0.437-0.816 mm); group 3, 0.605 +/- 0.099 mm (range, 0.454-0.945 mm); group 4, 0.607 +/- 0.120 mm (range, 0.410-0.781 mm). There was no significant correlation between vision and corneal thickness (P = 0.312). There was no statistical difference in pachymetry among all 4 groups (P = 0.323). The influence of pachymetry in visual acuity is not relevant (r = 0.03).

CONCLUSIONS

The variance in corneal thickness in DLEK does not seem to influence visual results.

Tissue adhesive to treat 2-site corneal melting associated with topical ketorolac use

We report a case of a 78-year-old man presenting with 2 discrete areas of sterile corneal melting associated with chronic use of topical ketorolac after uneventful clear corneal phacoemulsification. He was treated successfully with tissue adhesive application. Patients receiving chronic topical ketorolac treatment, especially those with ocular surface abnormalities, can present with severe complications such as corneal melting.

Recurrence of corneal stromal dystrophies after penetrating keratoplasty

PURPOSE

To assess the rates of simple and clinically significant recurrences of stromal dystrophies in corneal grafts.

METHODS

We conducted a retrospective review of Wills Eye Hospital records from 1984 to 2001, identifying all patients with stromal corneal dystrophies who had penetrating keratoplasties. Kaplan-Meier curves and chi analysis were performed.

RESULTS

The study population consisted of 35 eyes (21 patients) with lattice dystrophy, 17 eyes (10 patients) with corneal dystrophy of Bowman's membrane (CDB), 14 eyes (eight patients) with macular dystrophy, seven eyes (five patients) with granular dystrophy, and four eyes (four patients) diagnosed with Schnyder's crystalline dystrophy. There was a simple recurrence in 21 (60%) eyes (14 patients) with lattice and in 15 (88%) eyes (eight patients) with CDB. The median time to simple recurrence for the first eye transplanted of each patient was 8.4 years for lattice and 2.0 years for CDB. After 5 years of follow-up, there was a clinically significant recurrence, manifested by recurrent erosions or associated with decreased visual acuity, in the first eye transplanted of each patient, respectively, in six (17.1%) and seven (20%) eyes with lattice and in two (11.8%) and three (17.6%) eyes with CDB.

CONCLUSION

Corneal dystrophy of Bowman's membrane has the highest rate of simple recurrence followed by granular and lattice dystrophies, respectively. However, the rate of clinically significant recurrence, both recurrent erosions and decreased visual acuity, in the first 5 years is similar in CDB and lattice dystrophies. Recurrence is infrequent in macular and Schnyder's crystalline dystrophy. As expected, in genetic diseases, the potential for recurrence exists and increases with follow-up time.

Descemet's membrane detachment after cataract surgery: management and outcome

OBJECTIVE

To analyze the possible causes of Descemet's membrane detachment (DMD) and the treatment and outcome of patients after cataract surgery.

DESIGN

Retrospective noncomparative interventional case series.

PARTICIPANTS

Fifteen eyes of 12 patients.

METHODS

We reviewed clinical data on 15 eyes of 12 patients with nonscrolled DMD after cataract surgery who presented to the Cornea Service at Wills Eye Hospital from 1986 to 2001. Institutional review board/ethics committee approval was obtained.

MAIN OUTCOME MEASURES

Visual acuity and reattachment of Descemet's membrane.

RESULTS

Cataract procedures involved nine clear-corneal eyes, four limbal incisions, one trabeculectomy/combined phacoemulsification, and one extracapsular cataract extraction. From 1986 to 1990, we had 1 patient; from 1991 to 1995, no patients; and from 1996 to 2001, 11 patients (including all clear-corneal eyes). Of the 15 eyes, 8 resolved with medical treatment alone, with a mean time to resolution of 9.8 weeks. One patient was lost to follow-up while improving on medical treatment, and another required a penetrating keratoplasty (PK) after medical treatment failed. Five eyes received anterior-chamber SF(6) gas injection. Of these eyes, three DMDs resolved, one underwent repeated injection (not improving after 10 weeks), and another required a PK.

CONCLUSIONS

Referrals for DMD seem to be increasing. This may be explained by the increase in clear-corneal cataract procedures. Medical treatment seems to be adequate in many cases and may be appropriate initial therapy. When needed, SF(6) gas injection may also be successful, but not in all cases.

Excimer laser phototherapeutic keratectomy retreatment of anterior basement membrane dystrophy and Salzmann's nodular degeneration with topical mitomycin C

PURPOSE

To report a case of excimer laser phototherapeutic keratectomy retreatment of anterior basement membrane (ABM) dystrophy and Salzmann's nodular degeneration with a single intraoperative application of topical mitomycin C (0.02%).

METHODS

Case report.

RESULTS

A 91-year-old woman underwent excimer laser phototherapeutic keratectomy (PTK) in the left eye for ABM dystrophy and Salzmann's nodular degeneration causing decreased visual acuity (VA), ocular irritation, and recurrent erosions. Slit-lamp examination of both eyes revealed diffuse ABM dystrophy changes with mild to moderate subepithelial and anterior stromal haze and scarring involving the visual axis. The PTK treatment was preceded by a superficial keratectomy with a blade. The excimer laser was set for a 6-mm circular ablation zone with a treatment depth of 5 microm. The cornea remained clear for several months. Six months after surgery, the patient presented with difficulty reading and VA of 20/70. Slit-lamp examination of the left eye revealed recurrent Salzmann-type nodular degeneration inferior to the visual axis. A treatment course of topical steroids was not successful. She underwent another superficial keratectomy with a blade and PTK treatment (same laser parameters as the first procedure) with a 2-minute application of 0.02% mitomycin C on a cellulose sponge. The surgery proceeded without complications. On postoperative day 7, she presented with a healed epithelium and faint anterior stromal haze. Best-corrected visual acuity was 20/50, which is her best-expected VA. Six months after the procedure, the cornea revealed no signs of recurrence.

CONCLUSION

The use of topical mitomycin C in conjunction with PTK may prevent recurrence of Salzmann's nodular degeneration.