Combined interrupted and continuous versus single continuous adjustable suturing in penetrating keratoplasty: a prospective, randomized study of induced astigmatism during the first postoperative year

Post-penetrating keratoplasty astigmatism

Postoperative astigmatism is one of the common complications affecting visual outcomes after a penetrating keratoplasty. It can result from various factors related to host, donor and surgical technique, resulting in suboptimal visual outcome. While some of the measures taken during preoperative planning and during actual surgery can reduce the magnitude of postoperative astigmatism, postoperative correction of astigmatism is often required in cases with high degrees of astigmatism. When spectacles and contact lenses fail to provide optimal visual outcomes, various surgical techniques that include astigmatic keratotomy, compression sutures, toric intraocular lens placement, and laser refractive procedures can be considered. When none of these techniques are able to achieve a desired result with in the acceptable optical range, a repeat keratoplasty is considered a last option. We discuss the various causes and management of complication of postoperative astigmatism occurring after a full thickness corneal transplantation surgery.

Comparison of manual and femtosecond astigmatic keratotomy in the treatment of postkeratoplasty astigmatism

PURPOSE

To compare the outcomes of femtosecond astigmatic keratotomy (FSAK) and manual astigmatic keratotomy (AK) in treatment of postkeratoplasty astigmatism.

METHODS

A retrospective, comparative, pairwise-matched case series including 150 patients who underwent either FSAK (n = 75) or manual AK (n = 75) for the treatment of astigmatism (>3.00 D) following penetrating keratoplasty or deep anterior lamellar keratoplasty. Pairwise matching for baseline variables (age, visual acuity and astigmatism) was performed.

RESULTS

Mean age was 57.5 ± 16.0 years. The FSAK group had significantly better postoperative best-corrected visual acuity (BCVA) (p = 0.010), uncorrected visual acuity (UCVA) (p = 0.049), corneal astigmatism (p = 0.020) and manifest astigmatism (p < 0.001) compared with the manual AK group. Gain of ≥3 lines in BCVA (logMAR) was seen in five eyes (6.7%) and 21 eyes (28.0%) in manual AK and FSAK, respectively (p = 0.005). Alpins vector analysis showed lower (closer to 0) index of success (0.50 ± 0.24 and 0.79 ± 0.48, p < 0.001) and higher (closer to 1) correction index (0.94 ± 0.45 and 0.74 ± 0.55, p = 0.020) in FSAK compared with manual AK. Corneal and manifest astigmatism improved significantly in both groups, while BCVA and UCVA improved significantly in FSAK only. Repeat AK rate was 32% (24 eyes) in manual AK and 4% (three eyes) in FSAK (p < 0.001). Overcorrection-related re-suturing rate was 0% in manual AK and 8% (six eyes) in FSAK (p = 0.037). There was one microperforation (1.3%) in FSAK, and there were no occurrences of graft dehiscence, infectious keratitis or graft rejection.

CONCLUSIONS

Both manual AK and FSAK were safe and effective in reducing postkeratoplasty astigmatism. FSAK had superior visual and keratometric outcomes compared with manual AK.

Stepwise Combination of Femtosecond Astigmatic Keratotomy With Phacoemulsification and Toric Intraocular Lens Implantation in Treatment of Very High Postkeratoplasty Astigmatism

PURPOSE

To report the outcomes of stepwise combined femtosecond astigmatic keratotomy (FSAK) and phacoemulsification with toric intraocular lens (IOL) implantation in the treatment of very high astigmatism after either penetrating keratoplasty or deep anterior lamellar keratoplasty.

METHODS

This is a retrospective, interventional case series including 8 eyes of 6 patients with very high astigmatism [≥8.00 diopter (D)] after either penetrating keratoplasty or deep anterior lamellar keratoplasty who underwent FSAK, followed by phacoemulsification and toric IOL implantation. Outcome measures were corneal and manifest astigmatism and uncorrected and best spectacle-corrected visual acuity (UCVA, BSCVA).

RESULTS

The average age was 58.9 ± 5.1 years. The average follow-up time was 40.9 ± 43.8 months. Outcome measure changes after both FSAK and toric IOL implantation were: corneal astigmatism improved from 13.56 ± 4.81 D to 4.48 ± 2.83 D (P < 0.001), manifest astigmatism improved from 9.15 ± 3.86 to 1.46 ± 0.88 D (P = 0.011), UCVA improved from 1.69 ± 0.45 LogMAR (Snellen equivalent ∼20/980) to 0.23 ± 0.11 LogMAR (Snellen equivalent ∼20/33, P < 0.001), and BSCVA improved from 1.01 ± 0.71 LogMAR (Snellen equivalent ∼20/200) to 0.19 ± 0.11 LogMAR (Snellen equivalent ∼20/30, P = 0.015). BSCVA and UCVA at the last follow-up were 20/40 or better in all patients. All procedures were uneventful. Two eyes underwent photorefractive keratectomy after FSAK to regularize and further reduce astigmatism before toric IOL implantation. One patient underwent temporary compression suturing because of FSAK overcorrection.

CONCLUSIONS

Combined stepwise use of FSAK and phacoemulsification with toric IOL implantation was an effective and apparently safe approach in patients with very high postkeratoplasty astigmatism. Additional treatment using photorefractive keratectomy may be beneficial in some cases.

Post-keratoplasty astigmatism management by relaxing incisions: a systematic review

Postoperative visual acuity can be limited by post-keratoplasty astigmatism, even with a clear corneal graft. Astigmatism management can be performed by selective suture removal, adjustment of sutures, optical correction, photorefractive procedures, wedge resection, intra-ocular lens implantation, intracorneal ring segments, relaxing incisions with or without compression sutures and repeated keratoplasty. Relaxing incisions can be made in the graft, graft-host interface or host cornea. Despite the unpredictability of the method because the flat and steep meridians are usually not orthogonal after penetrating keratoplasty, with asymmetric power distribution, all the studies showed an overall reduction of refractive, keratometric or topographic astigmatism, ranging from 30% to 72% with manual or femtosecond-assisted techniques. Most patients with astigmatism higher than 6 diopters had residual cylinder less than or equal to 3 diopters, which can be treated by laser excimer ablation or secondary intraocular lens implantation.

Management of post-keratoplasty astigmatism

Post-keratoplasty astigmatism remains a challenge for corneorefractive surgeons. While maintaining a healthy graft is the most crucial issue in keratoplasty procedures, astigmatism is a limiting factor in the visual rehabilitation of otherwise successful corneal grafts. The management of post-keratoplasty astigmatism takes place at 2 stages: when sutures are still present at the graft-host junction and when all sutures have been removed. Excessive suture-in post-keratoplasty astigmatism is usually managed by selective suture manipulation, ie, suture adjustment and/or suture removal along the steep meridian of astigmatism. A small amount of suture-out post-keratoplasty astigmatism can be managed by spectacles. Higher magnitudes of astigmatism can be addressed by contact lenses or surgical intervention, such as relaxing and compressing procedures. Laser lamellar refractive surgery can also be used to manage post-keratoplasty astigmatism, and toric phakic intraocular lenses have recently been recommended. In this review, we discuss the etiology and management of post-keratoplasty astigmatism and provide recommendations and tips to minimize it.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.

Current approaches for management of postpenetrating keratoplasty astigmatism

A successful corneal graft requires both clarity and an acceptable refraction. A clear corneal graft may be an optical failure if high astigmatism limits visual acuity. Intraoperative measures to reduce postkeratoplasty astigmatism include round and central trephination of cornea with an adequate size, appropriate sutures with evenly distributed tension, and perfect graft-host apposition. Suture manipulation has been described for minimising early postoperative astigmatism. If significant astigmatism remains after suture removal, which cannot be corrected by optical means, then further surgical procedures containing relaxing incisions, compression sutures, laser refractive surgery, insertion of intrastromal corneal ring segments, wedge resection, and toric intraocular lens implantation can be performed. When astigmatism cannot be reduced using one or more abovementioned approaches, repeat penetrating keratoplasty should inevitably be considered. However, none of these techniques has emerged as an ideal one, and corneal surgeons may require combining two or more approaches to exploit the maximum advantages.

Clinical validation of point-source corneal topography in keratoplasty

PURPOSE

To validate the clinical performance of point-source corneal topography (PCT) in postpenetrating keratoplasty (PKP) eyes and to compare it with conventional Placido-based topography.

METHODS

Corneal elevation maps of the anterior corneal surface were obtained from 20 post-PKP corneas using PCT (VU topographer, prototype; VU University Medical Center, Amsterdam, The Netherlands) and Placido-based topography (Keratron, Optikon 2000, Rome, Italy). Corneal surface parameters are calculated in terms of radius and asphericity. Corneal aberrations were characterized using standard Zernike convention. An artificial surface with quadrafoil feature (SUMIPRO, Almelo, The Netherlands) was measured and used as a reference to assess instrument performance compared with the gold standard.

RESULTS

The differences (mean ± std of PCT - Placido) found between the two types of topographers in measurements of post-PKP eyes are 0.02 ± 0.21 mm (p=0.64) for radius of curvature, 0.14 ± 0.49 (p=0.23) for asphericity, -0.19 ± 1.67 μm (p=0.61) for corneal astigmatism, -0.25 ± 1.34 μm (p=0.41) for corneal coma, 0.23 ± 0.82 μm (p=0.23) for corneal trefoil, and 0.15 ± 0.28 μm (p=0.02) for corneal quadrafoil. The PCT measured the artificial surface more accurate (rms error 0.16 μm; 0.12 eq. Dpt.) than the Placido-based topographer (rms error 1.50 μm; 1.15 eq. Dpt.).

CONCLUSIONS

PCT is more accurate than Placido-based topography in measuring quadrafoil aberration.

Does the type of suturing technique used affect astigmatism after deep anterior lamellar keratoplasty in keratoconus patients?

PURPOSE

To compare the effect of three different suturing techniques on astigmatism after deep anterior lamellar keratoplasty (DALK) in patients with keratoconus.

METHODS

In this retrospective study, 54 eyes of 54 patients with advanced keratoconus underwent DALK with three suturing techniques: single running, interrupted running, and combined interrupted and running. Postkeratoplasty astigmatism was evaluated during examinations 1, 3, and 6 months postoperatively and 2 months after completing suture removal.

RESULTS

Twenty-four eyes had single running sutures, 16 eyes had interrupted sutures, and in 14 eyes the suturing technique used was combined interrupted and running sutures. Mean age was 25.6 ± 5.9 years, 27.3 ± 6.8 years, and 26.5 ± 5.7 years (P = 0.422), and postoperative astigmatism 1 month after surgery was 3.79 ± 1.19 D, 5.56 ± 1.78 D, and 4.21 ± 1.55 D in the three groups, respectively (P = 0.012). However, 2 months after completing the suture removal, final postoperative astigmatism was 3.43 ± 1.44 D, 3.87 ± 1.38 D, and 3.71 ± 1.46 D (P = 0.846). Final astigmatism less than 4 D was seen in 18 cases (75%) in the single running group, nine cases (56.2%) in the interrupted running group, and nine cases (64.2%) in the combined interrupted and running group (P = 0.08).

CONCLUSION

Postkeratoplasty astigmatism is comparable with three different suturing techniques used in patients with keratoconus after completing suture removal in DALK. Due to earlier suture removal in DALK, the type of suturing technique used is not considerably important.

Optical coherence tomography anatomy of the corneal endothelial transplantation wound

PURPOSE

The goal of this study was to prospectively assess the deep lamellar endothelial keratoplasty (DLEK) wound anatomy and its evolution during the 12 months after surgery, using optical coherence tomography (OCT).

METHODS

The eyes of 8 patients (1 eye per patient) who consecutively underwent DLEK for Fuchs dystrophy or pseudophakic bullous keratopathy were prospectively studied before and 1, 3, 6, and 12 months after surgery. The Stratus OCT apparatus (Carl Zeiss Meditec, Dublin, CA) was used to acquire central and radial scans perpendicular to the wound at 3-, 6-, 9-, and 12-o'clock positions. The following parameters were analyzed: central total thickness, posterior donor-recipient edges gap, donor-recipient height mismatch, tissue compression, and graft detachment.

RESULTS

A posterior gap was observed in 4 of the 8 DLEK eyes. At 12 months, the mean gap contour, depth, and width were 242 +/- 67, 101 +/- 45, and 87 +/- 29 microm, respectively. A step was documented in all DLEK eyes (average step height 108 +/- 24 microm). A micrograft detachment was observed in one case and tissue compression in another. In all corneas, the mean central corneal thickness returned to normal range and almost normal anatomy with time after surgery.

CONCLUSIONS

OCT was found to be a very useful tool for DLEK corneal wound architecture analysis. It revealed microscopic wound irregularities and allowed their quantitative follow-up with time.

Comparison of the effect of three suturing techniques on postkeratoplasty astigmatism in keratoconus

PURPOSE

To compare the effect of 3 common suturing techniques on postkeratoplasty astigmatism and final best corrected visual acuity (BCVA) in patients with keratoconus.

METHODS

In this randomized clinical trial, 103 eyes of 103 patients with advanced keratoconus, who were contact lens intolerant, or with contact lens-corrected visual acuity less than 20/80, underwent penetrating keratoplasty with 3 suturing techniques: interrupted (IR), single running (SR), and combined interrupted and running (CIR). Postkeratoplasty astigmatism and BCVA were evaluated during regular examinations 1.5, 3, 6, and 12 months postoperatively and 2 months after complete suture removal. Suture adjustment and selective suture removal were performed 2 to 6 weeks and after 3 months in eyes with more than 4 D of corneal astigmatism in the SR and IR/CIR groups, respectively.

RESULTS

Of 87 patients who completed follow-up, 26 eyes underwent PK with interrupted suturing technique (IR), 26 eyes had single running sutures (SR), and in 35 eyes, the suturing technique was combined (interrupted + running sutures; CIR). Mean age was 27.2 +/- 8.4, 28.9 +/- 8.7, and 30.3 +/- 8.7 years, and postoperative astigmatism 1.5 months after surgery was 3.77 +/- 1.68, 5.48 +/- 2.09, and 4.10 +/- 1.79 D in the 3 groups, respectively (P = 0.015). However, 2 months after complete suture removal, final postoperative astigmatism was 3.83 +/- 1.65, 3.37 +/- 1.9, and 3.88 +/- 2.79 D (P = 0.851) and BCVA (log MAR) was 0.08 +/- 0.14, 0.13 +/- 0.23, and 0.09 +/- 0.16, respectively (P = 0.53). Immunologic endothelial rejection reactions were seen in 5 eyes (19.2%) in the IR group, 3 eyes (11.72%) in the SR group, and 6 eyes (17.64%) in the CIR group (P = 0.44). There was no case of graft failure during the follow-up period.

CONCLUSION

Postkeratoplasty astigmatism and BCVA are comparable with the 3 common suturing techniques (IR, SR, and CIR) in patients with keratoconus, provided that regular postoperative examinations and topography-guided suture adjustment and/or removal are performed.

Femtosecond-laser arcuate wedge-shaped resection to correct high residual astigmatism after penetrating keratoplasty

We describe a standardized technique of femtosecond (FS) laser arcuate resection (LAR) in which intersecting arcuate cuts are used to perform a wedge resection for the correction of high astigmatism. A simple formula was used to calculate the relative decentration of the arcuate cuts based on the radii of curvature and desired wedge width to be resected. Feasibility of the procedure was established in porcine corneas before treatment of a patient with 20 diopters (D) of post-keratoplasty astigmatism. The astigmatism was reversed. Suture removal resulted in reduction of 14.5 D of astigmatism. Laser arcuate resection can be an effective alternative to manual wedge resection, allowing easier, more controlled, and more precise excision of tissue in width, length, and depth.

Deep lamellar keratoplasty by intracorneal dissection: a prospective clinical and confocal microscopic study

OBJECTIVE

To evaluate the clinical findings, visual outcomes, and confocal microscopic corneal features of a surgical technique for manual deep lamellar keratoplasty (DLKP) with intentional sparing of the most posterior stroma.

DESIGN

Noncomparative, prospective, 12-month interventional study.

PARTICIPANTS

Forty-six eyes of 45 patients who had corneal pathologic features without endothelial abnormalities and requiring corneal graft were treated by DLKP by manual stromal delamination. They were examined clinically after surgery and using in vivo confocal microscopy at 2 weeks and 1, 3, 6, and 12 months.

INTERVENTION

The surgical technique consisted of an intracorneal deep manual stromal dissection through a 4-mm limbal incision at 50 mum from Descemet's membrane (DM). After trephination, an endothelial free graft was sutured.

MAIN OUTCOME MEASURES

Topographic parameters, interface depth and reflectivity, and anterior and postinterface keratocyte density; visual acuity was correlated with these parameters.

RESULTS

Two eyes had rupture of the DM. Two eyes that had delayed epithelial healing because of graft override with stromal inflammation underwent a second surgery (penetrating keratoplasty). Mean uncorrected logarithm of the minimum angle of resolution (logMAR) uncorrected visual acuity and logMAR best-corrected visual acuity (BCVA) improved from preoperative values (1.342+/-0.239 and 0.923+/-0.226, respectively) to 0.421+/-0.122 and 0.104+/-0.068, respectively, at 12 months. Mean topographic astigmatism was 3.09+/-1.30 diopters (D) at 3 months after suture adjustment, and 2.87+/-0.92 D at 12 months after suture removal. Average interface depth was 64.2+/-6.7 microm at 15 days and showed no significant changes up to 12 months. Mean interface reflectivity was highest at 15 days (95.5+/-15.7 light reflectance units [LRU]) and showed a progressive decrease over time of 55.3+/-8.7 LRU at 12 months. A significant negative correlation was observed between BCVA and topographic astigmatism up to 1 month and between BCVA and interface reflectivity starting from 6 months after surgery.

CONCLUSIONS

Deep lamellar keratoplasty by intracorneal dissection provides visual and clinical results comparable with that of other DLKP techniques. Visual recovery is slow and progressive, taking up to 1 year. Confocal microscopy enables precise evaluation of corneal features, interface morphologic features, and reflectivity, demonstrating a negative correlation between interface reflectivity and BCVA showing that the progressive recovery over months of the interface transparency is correlated with the increase in visual acuity after 6 months.

Comparison of complication rates and postoperative astigmatism between nylon and mersilene sutures for corneal transplants in patients with Fuchs endothelial dystrophy

PURPOSE

The purpose of this study is to evaluate corneal astigmatism and suture-related complications for transplants sutured with nylon and transplants sutured with Mersilene in primary corneal transplants for Fuchs endothelial dystrophy.

METHODS

A retrospective, observational, and comparative study between transplants sutured with either nylon 10-0 or 11-0 (n = 108) or Mersilene 11-0 (n = 58) was done. One hundred sixty-six eyes of 140 patients who received a primary penetrating keratoplasty for Fuchs endothelial dystrophy between 1995 and 2001 at the Rotterdam Eye Hospital in Netherlands were included.

RESULTS

Overall, transplant survival did not differ between groups (log-rank test; P = 0.24). During the first 2 years after transplantation, significantly lower astigmatism was seen in transplants sutured with nylon (P = 0.03). Transplants sutured with Mersilene had a significantly higher risk of surgical intervention to correct astigmatism or wound dehiscence after transplantation (hazard ratio, 2.83; 95% confidence interval, 1.34-6.01). Time to first infiltrate, metaplasia (marked scarring along the sutures), or cheesewiring was significantly less in the Mersilene group (P < 0.01). There was a tendency toward a higher risk of complications associated with loose or broken sutures in the nylon group (hazard ratio, 2.00; 95% confidence interval, 0.57-6.98), which was more pronounced after 2 years.

CONCLUSIONS

During the first years after corneal transplant surgery, Mersilene sutures are associated with a higher risk of complications and more interventions to correct suture-related problems. However, after 2 years, the grafts seem to be able to retain Mersilene sutures with less risk of suture-related complications as compared with grafts with retained nylon sutures. These favorable long-term effects of Mersilene sutures may outweigh its short-term disadvantage in patients with Fuchs endothelial dystrophy.

A Review of Randomized Controlled Trials of Penetrating Keratoplasty Techniques

PURPOSE

To assess the effects of variations in operative technique on the outcomes of penetrating keratoplasty (PK).

METHOD

Systematic literature review of published randomized controlled trials of operative techniques in PK.

MAIN OUTCOME MEASURES

Visual acuity, refractive error, endothelial cell density, graft rejection, intraocular pressure (IOP), and other surgical complications.

RESULTS

Twenty-seven trials were identified. Many involved small numbers, some of which were probably compromised by inadequate statistical power. There was some limited evidence from a small number of studies (usually 1 or 2) for preoperative cauterization of the cone in keratoconus, excimer laser trephination, taking into account the effect of trephine sizing on postoperative IOP, taking into account the effect of trephine sizing on postoperative spherical equivalent, using sodium hyaluronate, avoiding vitrectomy if possible, using an iris-fixated posterior chamber lens implant in the absence of capsular support, and adjusting a single continuous suture intraoperatively if used. However, there was little convincing evidence for choosing interrupted suturing versus continuous suturing or for an effect of suturing on final sutures-out astigmatism. Likewise, there was no convincing evidence for the superiority of any lamellar alternative to PK for deep stromal disease. Overall, most of the effects of changing technique were small, and there was no evidence for the superiority of any specific technique in terms of improved quality of life or cost-effectiveness.

CONCLUSIONS

There is a need for further studies with which to refine decision-making as regards the choice of operative techniques in PK.

Centennial review of corneal transplantation

Abstract One hundred years ago, on 7 December 1905, Dr Eduard Zirm performed the world's first successful human corneal transplant. This significant milestone was achieved only after many decades of unsuccessful trial and error; however, it did not lead to relatively 'routine' keratoplasty success for several more decades. The idea of replacing an opaque cornea had been suggested for centuries, and had stimulated theoretical approaches to the problem by many esteemed physicians throughout history. However, little practical progress was made in the ultimate realization of the dream until the 19th century when pioneering surgeons pursued extensive studies in relation to both animal and human 'keratoplasty'. Clinical progress and scientific insight developed slowly, and it was ultimately due to parallel advances in medicine such as anaesthesia and antisepsis that Zirm's success was finally achieved. Key concepts were enshrined such as the use of fresh tissue from the same species, careful placement and handling of tissue, and the development of specialized instrumentation such as the circular trephine. In the latter half of the 20th century, many 'masters' of corneal surgery evolved significant refinements in technique and instrumentation with the development of corticosteroids, antibiotics, surgical microscopes, improved trephines, viscoelastics and suture materials, that enable this delicate procedure to be routinely performed with the prospect of success. There are still limitations to corneal transplantation, and corneal allograft rejection still poses the greatest challenge to the modern corneal surgeon. In the foreseeable future it may be in the laboratory, rather than the theatre, that further milestones will be achieved. This review aims to highlight the significant milestones in the rich history of corneal transplantation, and to pay tribute to the many inspired and dedicated individuals involved in the development of keratoplasty to a point where the procedure is now a standard tool in the repertoire of ophthalmic surgery and more than a million people have enjoyed restoration of useful sight.

Outcomes of penetrating keratoplasty in keratoconus

PURPOSE

Keratoconus (KCN) is one of the most common indications of corneal transplantation in Iran. This study was conducted to determine the outcomes of penetrating keratoplasty (PK) for KCN in patients operated in a private practice setting from 1994 to 2001.

METHODS

This longitudinal retrospective study included 164 eyes of 164 patients. Variables included preoperative keratometry, trephination and suturing techniques, donor-recipient disparity, surgical complications, immunologic rejection, graft clarity, postoperative spherical and cylindrical refractive error, keratometry, uncorrected and best spectacle-corrected visual acuity, suture management, and the results of keratorefractive procedures.

RESULTS

Patients were followed for a mean period of 33.5 months. Mean postoperative best spectacle-corrected visual acuity (BSCVA) at last follow-up was 0.14 +/- 0.11 LogMAR (20/25); mean spherical error and mean corneal astigmatism were -0.61 +/- 2.6 and 3.4 +/- 1.8 D, respectively. Final visual outcomes were not significantly correlated with trephination and suturing techniques or severity of the ectasia. Although donor-recipient disparity did not affect final astigmatism, more myopic shift was observed with greater disparity, but this finding was not of statistical significance. Overall, 26.8% of the patients required keratorefractive surgery, which resulted in 2.9 D reduction in corneal astigmatism. Immunologic graft rejection occurred in 28% of cases; however, all episodes responded to medical management, and none resulted in graft failure.

CONCLUSION

Penetrating keratoplasty is a safe and effective procedure with remarkable optical and visual outcomes for patients with keratoconus who are contact lens intolerant or have unacceptable corrected visual acuity. Neither severity of the disorder nor trephination and suturing techniques significantly affects final visual outcomes. Less graft-recipient disparity (0.25 versus 0.50 mm) seems to induce less myopic shift.

Deep Lamellar Endothelial Keratoplasty

PURPOSE

To report the 6-month results for the treatment of endothelial dysfunction in a large, prospective series of deep lamellar endothelial keratoplasty (DLEK) procedures.

DESIGN

Prospective, noncomparative, interventional case series.

PARTICIPANTS

One hundred eyes of 88 patients with corneal edema from Fuchs' dystrophy and pseudophakia.

METHODS

A limbal, scleral, partial-depth incision provided access for a deep lamellar corneal pocket dissection. Two eyes were converted to penetrating keratoplasty (PK) at the time of DLEK surgery because of poor dissections. Of the 98 eyes that had completed DLEK surgeries, 36 eyes received a large-incision technique (9-mm scleral access incision) and 62 eyes received a small-incision technique (5-mm scleral access incision). A 7.5- to 8.0-mm posterior lamellar disc of recipient tissue then was excised and replaced through the pocket with a similar size donor disc containing healthy endothelium. A temporary air bubble in the anterior chamber was used for donor tissue adherence, and no surface corneal incisions or sutures were necessary.

MAIN OUTCOME MEASURES

Preoperative and postoperative best spectacle-corrected visual acuity (BSCVA), manifest refraction (MR) astigmatism, and endothelial cell density (ECD) were evaluated prospectively.

RESULTS

At 6 months after surgery, all 98 DLEK corneas were clear and the grafts were healed in good position. The mean BSCVA was 20/46, with a range between 20/20 and 20/400. The average MR astigmatism was 1.34+/-0.86 diopters (D), representing an average change in astigmatism from before surgery of +0.28+/-1.08 D (P = 0.013). The average ECD at 6 months was 2140+/-427 cells/mm2, representing a mean cell loss from preoperative donor cell measurements of 25%.

CONCLUSIONS

The DLEK procedure, with its absence of corneal surface incisions and sutures, preserves the normal corneal topography, minimizes astigmatism, and provides a healthy donor endothelial cell count and function. The DLEK procedure represents a reasonable alternative to PK, and compared with historical PK data, offers superior refractive outcomes in the treatment of endothelial dysfunction.

Small-Incision Deep Lamellar Endothelial Keratoplasty (DLEK)

PURPOSE

To evaluate the visual, topographic, and endothelial survival results in 25 consecutive patients who have received small-incision deep lamellar endothelial keratoplasty (DLEK) transplant surgery.

METHODS

DLEK surgery was performed in 25 patients with Fuchs endothelial dystrophy or pseudophakic bullous keratopathy utilizing a 5-mm scleral access incision. Snellen visual acuities, refractive astigmatism, endothelial cell counts, and corneal topography were prospectively measured at preop and at 6 months after small-incision DLEK endothelial replacement surgery.

RESULTS

Best spectacle-corrected visual acuity improved from an average of 20/90 (range 20/25 to 2'/200) before surgery to an average of 20/44 (range 20/25 to 20/200, P < 0.001) 6 months after surgery, with 56% of patients 20/40 or better at 6 months. Average refractive astigmatism at 6 months was 1.31 +/- 0.59 diopters (range 0.25 to 2.50 diopters), representing an average increase in astigmatism of 0.45 diopters from preop. Despite folding of the donor graft for placement into the recipient posterior lamellar bed, the average postoperative endothelial cell count at 6 months was 2122 +/- 510 cells/mm2 (range 1097 to 3202 cells/mm2) or an average 24% cell loss from donor eye preop measurements, a level of cell loss comparable to that reported after PK or after large-incision DLEK surgery.

CONCLUSION

Small-incision DLEK surgery preserves the recipient corneal topography, resulting in very little change in astigmatism from preop. The excellent postoperative donor endothelial cell counts attest to the survival of donor endothelium despite folding of the graft for insertion. The small-incision DLEK technique may become the standard for endothelial replacement surgery in the future.

Refractive outcome of single running suture adjustment in penetrating keratoplasty

PURPOSE

To evaluate the effectiveness of single running suture adjustment in reducing postoperative astigmatism and improving visual acuity in patients who have undergone penetrating keratoplasty.

METHODS

Eighteen eyes of 18 patients who underwent penetrating keratoplasty at the Department of Ophthalmology, Başkent University between May 1997 and December 2000 and who had an astigmatism over 2 diopters (D) at the fourth postoperative week were included. All eyes underwent suture adjustment at the fourth week and eight eyes with residual astigmatism above 3 D underwent a second adjustment at the eighth week. Final astigmatism and visual acuity findings were evaluated 28 weeks postoperatively.

RESULTS

The mean postoperative keratometric and refractive astigmatism were 5.76 +/- 0.88 D (range=4.50-7.76) and 5.22 +/- 0.78 D (range=4.0-7.0) at the fourth week, which were decreased to 2.82 +/- 0.99 D (range=1.25-4.62, p=0.0001) and 2.61 +/- 1.01 D (range= 1.0-4.5, p=0.0001) after suture adjustment, respectively. In eight eyes at the eighth week, a second suture adjustment reduced the average keratometric and refractive astigmatism from 3.86 +/- 0.65 D (range=2.75-4.62) and 3.81 +/- 0.44 D (range=3.25-4.50) to 2.33 +/- 0.91 D (range=0.87-3.50, p=0.012) and 2.06 +/- 0.68 D (range=1.0-2.75, p=0.011), respectively. At the 28th week, the average keratometric and refractive astigmatism levels for the entire cohort, which were 2.39 +/- 1.06 D (range=1.0-3.50) and 2.25 +/- 0.96 D (range=1.0-3.25), respectively, showed a statistically significant decrease when compared with the levels before the first suture adjustment (p=0.0001 for both data). The mean best-corrected visual acuity was 20/25 on the Snellen chart at the 28th week.

CONCLUSIONS

Postoperative adjustment of single running suture is a safe and effective way of reducing postkeratoplasty astigmatism.

Keratometric astigmatism after suture removal in penetrating keratoplasty: double running versus single running suture techniques

BACKGROUND AND OBJECTIVE

To compare astigmatism after suture removal in a retrospective sequential series of patients who had penetrating keratoplasty with either a double running suture technique or an adjustable single running suture technique. During the first year postkeratoplasty, when sutures were in place, the latter technique had produced less astigmatism.

MATERIALS AND METHODS

Keratometry and keratometric astigmatism were measured before and after suture removal. We compared these variables in 30 grafts with the double running suture technique to the same variables in 24 grafts with the single running suture technique.

RESULTS

The final portion of the double running suture was removed 408 +/- 177 (mean +/- SD) days after keratoplasty, whereas the single running suture was removed 611 +/- 224 days after keratoplasty (P<0.001). After suture removal, there was no difference between the double running and single running groups in either mean keratometry [46.5 +/- 1.8 diopters (D) versus 45.6 +/- 2.0 D, P=0.09, minimum detectable difference (MDD)=1.5D] or mean astigmatism (4.6 +/- 2.7 D versus 5.2 +/- 3.2D, P=0.72, MDD=2.3).

CONCLUSION

In this consecutive series of corneal transplants performed by one surgeon, the results suggest no difference in astigmatism between the two suturing techniques after all sutures have been removed.

Surgical technique for control of postkeratoplasty myopia, astigmatism, and anisometropia

PURPOSE

We previously demonstrated that selective suture removal reduces keratoplasty astigmatism; however, a myopic shift was induced with the increasing number of interrupted sutures removed. This study is an attempt to determine the effects of a modified surgical technique on postkeratoplasty myopia, astigmatism, and anisometropia.

DESIGN

A cohort study compared with historical controls.

METHOD

Optical penetrating keratoplasties were performed on 92 eyes of 84 patients. The study group consisted of 92 consecutive penetrating keratoplasties performed using 12 interrupted 10-0 nylon sutures and a tight 12-bite continuous suture and an average K reading of 46.00 diopters for eyes undergoing combined and intraocular lens exchange procedures. All patients had refraction, keratometry, and videokeratoscopy postoperatively starting at 6 weeks and at the completion of selective suture removal.

RESULTS

Before suture removal, the average spherical equivalent was -0.160 +/- 3.59 diopters; it was -1.58 +/- 3.66 diopters at the completion of suture removal at 1 year and -1.44 +/- 3.72 at the last follow-up visit, averaging 20.7 months. Final refractive, keratometric, and videokeratoscopy astigmatism was 2.81 +/- 1.82, 4.19 +/- 2.94, and 3.58 +/- 2.03 diopters, respectively. Anisometropia, using the spherical equivalent of the operated and fellow eyes, was 2.49 +/- 2.25 diopters at completion of the study. A best-corrected visual acuity of 20/50 or better was achieved in 59% of patients.

CONCLUSIONS

Low myopic spherical equivalent and anisometropia were achieved using a K reading of 46 diopters for calculation of intraocular lens power. The use of tighter continuous sutures and selective removal of fewer interrupted sutures only served to increase final astigmatism, with no significant effect on the final spherical equivalent.

A new technique for rigid gas permeable contact lens fitting following penetrating keratoplasty

PURPOSE

To evaluate a new, rigid gas permeable contact lens fitting technique following penetrating keratoplasty.

METHODS

For the correction of postoperative anisometropia or astigmatism, a rigid gas permeable, tetra-curve contact lens with an overall diameter of 12.0 mm and a back optic zone diameter of 8.5 mm was fitted in 36 eyes of 33 patients, 7 months after penetrating keratoplasty. The contact lens back optic zone radius was selected using the videokeratography values over the elevated edges of the transplant wound (with the sutures in place). Graft clarity, visual outcome, and corneal topography were evaluated up to 3 years after surgery at intervals of 6 months.

RESULTS

Throughout the follow-up period (range 6-36, mean 19.3+/-sd 11.8 months), all grafts remained clear. Mean contact lens daily wearing time averaged 13.6 (+/- sd 4.7) hours. Mean best-corrected visual acuity improved from +0.36 (+/- sd 0.18) LogMAR with spectacles to +0.11 (+/- sd 0.11) LogMAR with contact lenses (p < 0.0001). One patient was excluded from the study due to a lack of motivation and one had an adverse reaction to the stitches.

CONCLUSIONS

To improve the visual performance following penetrating keratoplasty, the described fitting technique, guided by videokeratography, eased selection of the back optic zone radius of the initial trial lens. The large diameter contact lenses with a tetra-curve design were well tolerated in all patients for more than 13 hours daily.

Laser in situ Keratomileusis for Correction of High Astigmatism After Penetrating Keratoplasty

PURPOSE

To evaluate the safety and efficacy of laser in situ keratomileusis (LASIK) for correction of high astigmatism after penetrating keratoplasty, and to assess the refractive results and predictability of the procedure.

METHODS

LASIK was performed on 19 patients (19 eyes) with high astigmatism after penetrating keratoplasty, using the Chiron Automated Corneal Shaper and the Chiron-Technolas Keracor 116 excimer laser. The amount of preoperative refractive astigmatism ranged from 6.50 to 14.50 D (mean, 9.21 +/- 1.95 D) and the spherical component of manifest refraction ranged from -7.00 to +1.25 D (mean, -2.14 +/- 2.11 D). All patients completed a minimum follow-up of 12 months.

RESULTS

Refraction was stable after 3 months. At 1 year after LASIK, the amount of refractive astigmatism was reduced to a mean of 1.09 +/- 0.33 D (range, 0.50 to 1.75 D), with 57.9% of the eyes within +/- 1.00 D of refractive astigmatism. The mean percent reduction of astigmatism was 87.9 +/- 3.7%. The postoperative spherical component of manifest refraction ranged from -1.00 to +1.75 D with a mean of +0.43 +/- 0.82 D. Vector analysis showed that the mean amount of axis deviation was 1.1 +/- 1.3 degrees and the mean percent correction of preoperative astigmatism was 92.6 +/- 8.4%. There were no intraoperative complications. Spectacle-corrected visual acuity was not reduced in any eye, and improved by 2 or more lines in 42.1% of eyes after LASIK.

CONCLUSION

LASIK with the Chiron-Technolas Keracor 116 excimer laser was effective for correction of both astigmatism and myopia after penetrating keratoplasty. The procedure proved to be safe and gave fairly predictable and stable refractive results.