Improved Technique of Circular Keratotomy for the Correction of Corneal Astigmatism

"Corneal Plication" for the Management of Progressive Corneal Graft Protrusion in Patients With Keratoconus: a New Technique

PURPOSE

The purpose of this study was to present a new surgical technique, namely corneal plication, for the management of high astigmatism and progressive corneal graft protrusion after penetrating keratoplasty (PKP) for keratoconus.

METHODS

New surgical approach description.

RESULTS

A 61-year-old woman with a history of bilateral keratoconus was referred to our institute for the management of progressive corneal graft protrusion in her left eye 25 years after PKP. On presentation, the uncorrected distance visual acuity in the involved eye was counting fingers, whereas slit-lamp examination revealed a clear graft with a crescentic area of thinning in the inferior host cornea, extending from 4 to 9 o'clock that resulted in significant graft protrusion and astigmatism. We proceeded with a novel surgical approach that included "folding" and suturing the thinned, diseased corneal tissue and thus creating a form of corneal plication. No intraoperative or postoperative complications were observed, and uncorrected distance visual acuity was 0.32 6 months after the operation.

CONCLUSIONS

Corneal graft plication may represent a realistic alternative to more invasive procedures, currently used for the management of this long-term post-PKP complication in patients with keratoconus because it is a nonperforating technique that seems to provide satisfactory anatomical and visual outcomes without the need for any tissue excision or regrafting.

Circular Keratotomy Combined With Wedge Resection in the Management of High Astigmatism After Penetrating Keratoplasty

OBJECTIVE

To evaluate the effectiveness of circular keratotomy combined with wedge resection for the management of high astigmatism after penetrating keratoplasty (PK).

METHODS

The study included seven eyes of seven patients with previous PK who underwent circular keratotomy combined with wedge resection. The uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA), spherical equivalent (SE) refraction, and keratometric powers obtained by corneal topography were evaluated. The power vector method was used to analyze the astigmatic change postoperatively.

RESULTS

The mean follow-up period was 18.42±8.56 months (range 12-33 months). Uncorrected visual acuity, BCVA, and SE were improved in all eyes postoperatively. The mean preoperative astigmatism reduced from 15.11±5.48 D (range, 10.0-24.4 D) to 4.98±3.01 D (range, 2.2-9.6 D), postoperatively. According to the vector analysis, the overall mean surgically induced astigmatism at last visit was 12.87±6.20 D. The most common complication was the loosening of sutures occurred in five eyes within 2 months.

CONCLUSIONS

Circular keratotomy combined with corneal wedge resection is a favorable option for the management of high astigmatism after PK.

Effect of circular keratotomy on keratoconus

Circular keratotomy was performed in 3 eyes of 3 patients with keratoconus before planned lamellar keratoplasty. After peribulbar anesthesia, a circular 400 microm cut centered on the geometrical corneal center was made using a Hessburg-Barron 7.0 mm trephine (Altomed). The circular cut was deepened with a guarded diamond blade set at 90% of the thinnest point in the circumference and closed with a single 10-0 nylon running suture. Videokeratography revealed increased astigmatism and increased central curvature in all eyes. In 1 patient, a 0.2 improvement in best spectacle-corrected visual acuity (BSCVA) was noted, associated with overall corneal steepening. In the other 2 patients, refraction, BSCVA, and corneal profile worsened, requiring lamellar keratoplasty. Circular keratotomy increased corneal curvature and worsened keratoconus and is therefore not recommended.

Arcuate Relaxing Incisions Guided by Corneal Topography for Postkeratoplasty Astigmatism

PURPOSE

To determine if using corneal topography for planning arcuate relaxing incision placement for postkeratoplasty astigmatism improves clinical results.

METHODS

Twenty-six eyes with high levels (> 5 diopters [D]) of postkeratoplasty astigmatism were studied in a nonrandomized, retrospective, observational case series. Relaxing incisions were placed in the peripheral graft in each steep topographic hemimeridian. The following data were measured: keratometric, topographic, and refractive vector analysis; nonvector astigmatism reduction; surface regularity and asymmetry (surface regularity index and surface asymmetry index); topography patterns; surgical design; and visual acuity.

RESULTS

Topographic analysis changed some aspect of the surgery in 51/52 incisions with a 15.7 degrees mean change in incision location. The mean vector correction index (CI) was 0.89 to 0.92 for keratometric, topographic, and refractive indices. Sixty-five percent of eyes had surgically induced astigmatism (SIA) values within 2 D of the surgical goal. Eighty-one percent of eyes had at least a 50% reduction in net astigmatism and 85% had < or = 3-D residual refractive cylinder. The mean logMAR visual acuity increased 2 lines. The preoperative and postoperative spherical equivalent showed a high correlation (rho = 0.914, P = 0.000). The correlation between SIA and targeted induced astigmatism (TIA) was 0.56 (P = 0.003). There was a significant improvement in surface regularity index (P = 0.000) and surface asymmetry index (P = 0.05) values. No statistically significant correlations were found between total incision length and SIA or TIA, or between TIA and correction index. All patients had symmetric (58%) or asymmetric (42%) bowtie topographic patterns preoperatively with 35% achieving round/oval patterns postoperatively.

CONCLUSIONS

Topography-guided relaxing incision offers an easy method to plan surgery and has some limited advantages over conventional techniques.

Artisan Toric Phakic Intraocular Lens for Correction of Astigmatism

PURPOSE

To assess the safety and efficacy of implanting Artisan toric phakic intraocular lenses (PIOLs) (Ophtec BV, Groningen, The Netherlands) in eyes with high degrees of compound myopic, hyperopic, and mixed astigmatism.

METHODS

Twenty-five eyes (20 patients) presenting with high astigmatism were implanted with Artisan toric PIOLs and followed for 1 year. Group 1 included 8 eyes (myopic astigmatism), group 2 included 9 eyes (hyperopic astigmatism), and group 3 included 8 eyes (mixed astigmatism).

RESULTS

In the myopic astigmatism group, 8 (100%) of 8 eyes had preoperative uncorrected visual acuity (UCVA) of < or = 20/50, and at 6-month follow-up, 5 (62.5%) of 8 eyes had UCVA of > or = 20/40 (P = .005). In this group, 75% of eyes were within +/- 1.00 diopter (D) of the intended correction. In the hyperopic astigmatism group, 8 (88.9%) of 9 eyes had preoperative UCVA of < or = 20/40, and at 6-month follow-up, 6 (66.6%) of 9 eyes had UCVA of > or = 20/32 (P = .199). Approximately 77.8% of eyes were within +/- 1.00 D of the intended correction. In the mixed astigmatism group, 8 (100%) of 8 eyes had preoperative UCVA of < or = 20/50, and at 6-month follow-up, 6 (87.5%) of 8 eyes had UCVA of > or = 20/40 (P = .007). In this group, 87.5% of eyes were within +/- 1.00 D of the intended correction. The safety index of the procedure was 1.6, 1.3, and 1.3 in the myopic, hyperopic, and mixed astigmatism groups, respectively. The efficacy index of the procedure was 1.2, 1.0, and 1.0 in the myopic, hyperopic, and mixed astigmatism groups, respectively.

CONCLUSIONS

Artisan toric PIOLs are safe for the correction of high degrees of astigmatism associated with myopic or hyperopic spherical refractive defect.

Corneal wedge resection to treat progressive keratoconus in the host cornea after penetrating keratoplasty

We present 3 cases of progressive keratoconus in the host after penetrating keratoplasty PKP that were treated with a wide crescentic excision of the diseased tissue in the host cornea guided by Orbscan II topography (Bausch & Lomb). In all cases, the procedure resulted in a more regular corneal shape with a marked reduction in astigmatism, preventing the need for repeat PKP

Effect of a standard paired arcuate incision and augmentation sutures on postkeratoplasty astigmatism

To analyze the efficacy of a standardized paired arcuate incision and augmentation suture technique in the treatment of various levels of post-penetrating keratoplasty (PKP) astigmatism. Lions Eye Institute, Royal Perth Hospital, Perth, Australia, and University of Dundee Department of Ophthalmology, Dundee, United Kingdom.A standardized paired arcuate incision and paired augmentation suture technique was used to treat 34 eyes with post-PKP astigmatism ranging from -3.50 to -20.00 diopters (D) at the spectacle plane. The technique consisted of paired arcuate incisions of 3 clock hours, 480 microm deep in the graft-host junction, and 2 pairs of augmentation 10-0 nylon sutures. The mean preoperative cylinder was -9.14 D +/- 4.38 (SD) and the mean postoperative cylinder, -3.59 +/- 1.92 D at the corneal plane after a mean follow-up of 50 +/- 43 weeks. This represents an empirical reduction in mean cylinder of 5. 55 D (60.7%). The Alpins correction index (surgically induced astigmatism [SIA] divided by target induced astigmatism) was calculated for each case, and the mean was 1.01 +/- 0.34, with a median of 0.91. Approximately 53.1% of cases achieved a correction index between 0.80 and 1.20, and the correction index correlated poorly with the initial magnitude of cylinder. A direct numerical relationship between SIA and the initial magnitude of cylinder was observed, although a standard surgical procedure was used in all cases.A simple standardized technique using paired arcuate incisions in the graft-host junction with paired augmentation sutures reduces the amount of cylinder in proportion to the magnitude of the preoperative cylinder and effectively reduces post-PKP astigmatism.

Experimental Circular Keratotomy for Correction of Corneal Astigmatism

PURPOSE

To investigate the effect of circular keratotomy depth and diameter on corneal astigmatism.

METHODS

High astigmatism was induced in 25 human donor eyes by an anterior radial 7-0 silk suture across the corneoscleral limbus. With a 6.0, 6.5, 7.0, or 7.5 mm trephine, a 0.3 mm deep circular incision was made in 20 donor eyes. In 5 donor eyes 5 circular incisions were made with a diamond knife set at 0.1, 0.2, 0.3, 0.4, and 0.5 mm depths.

RESULTS

The reduction of astigmatism between the 4 groups in which different trephination diameters were used showed no statistically significant difference (P > .1). The relationship between incision depth and reduction of astigmatism was statistically significant (P < .001).

CONCLUSION

Artificially induced corneal astigmatism was reduced by a circular keratotomy in this donor eye model. Deeper incisions showed a greater effect.