[Decentration of donor cornea in mechanical and excimer laser trephination for penetrating keratoplasty]

BACKGROUND AND PURPOSE

Decentration of the trephination is supposed to be one of the major reasons for high and/or irregular astigmatism after penetrating keratoplasty (PK). The purpose of this study was to assess the amount and direction of donor decentration with conventional mechanical and nonmechanical laser trephination.

PATIENTS AND METHODS

In this retrospective analysis 106 consecutive mechanical donor trephinations from the endothelial side (mean diameter 7.30 +/- 0.79 mm), 80 mechanical donor trephinations from the epithelial side (mean diameter 7.30 +/- 0.77 mm), and 89 nonmechanical donor trephinations from the epithelial side (Aesculap-Meditec; spot profile 1.5 x 1.5 mm, pulse energy 18-20 mJ, repetition rate 25/s) along metal aperture masks (mean diameter 7.72 +/- 0.40 mm) were included. Remaining corneoscleral rims were fixed in formalin after trephination and photographed from the endothelial side. On colour prints (13 x 18 cm; total magnification x7.33) the amount and direction of decentration were assessed morphometrically using the SummaSketch (Summagraphics, Seymour, USA) and correlated with the total area of the cornea and the trephination.

RESULTS

Mean donor decentration was significantly smaller with laser trephination (0.20 +/- 0.12 mm) than with mechanical trephination from the endothelial side (0.26 +/- 0.14 mm; p = 0.001) and from the epithelial side (0.27 +/- 0.16 mm; p = 0.024). In addition, donor decentration correlated significantly inversely with the trephination area (p < 0.001), but not with the total area of the cornea (p = 0.63). A preferred direction of decentration relative to the microsurgeon could not be detected (p = 0.87).

CONCLUSIONS

Centration of donor trephination can be improved by using nonmechanical instead of mechanical trephination of the cornea. Further studies are required to investigate the clinical relevance of the statistically better donor centration on astigmatism and visual acuity after PK.

[Contribution of the Kansas technique for reducing complications of mature cataract surgery]

PURPOSE

We report our experience with the Kansas technique of phakosection which eliminates or limits most complications of classic manual extracapsular extraction.

PATIENTS AND METHODS

This retrospective study included our first 80 patients undergoing surgery for mature cataract between May 1996 and May 1998 where we used the Kansas technique. We compared outcome with a group of 30 patients who underwent classic manual extracapsular extraction in a study performed in 1995 by the same surgeon in the same hospital.

RESULTS

Per- and post-operative complications were significantly lower with phakosection. Functional rehabilitation was quicker, better and provided better patient comfort.

DISCUSSION

Despite some difficulties encountered in a public hospital (viscoelastic excessively fluid and in small quantity, lack of suitable knives or reuse of sterilized disposable knives), we found that the Kansas technique is very well adapted to mature cataracts and our working conditions.

CONCLUSION

Phakosection allowed us to give our patients with mature or very mature cataracts the benefit of small incisions. With a moderate increase in cost, this technique significantly reduced our per- and post-operative complication rates and gave quicker and better visual recovery. In our countries, this technique provides better care than phakoemulsification.

Corneal refractive changes after acrysof lens versus PMMA lens implantation

PURPOSE

Do foldable acrylic lenses yield not only reduced posterior capsular opacification but also significant refractive advantages?

PATIENTS AND METHODS

147 cataract patients including 47 with spherical corneas and 100 with preoperative astigmatism of 0.8 +/- 0. 7 dpt were treated in one of two ways: 70 patients received 5.5-mm Acrysof lens implants through 3.2-mm outer and 4-mm inner temporal clear corneal openings (stretch incision); 77 patients received 5-mm PMMA lenses through temporal clear corneal incisions of 4.1-mm outer and 6.5-mm inner diameter incisions. Corneal topography was examined in all patients before the operations as well as 3 days and 6 months after the operations.

RESULTS

6 months after the operations, we observed a surgically induced astigmatism of 0.4 +/- 0.2 dpt for the 3.2-mm incisions compared to 0.8 +/- 0.7 dpt for the 4.1-mm incisions; evaluation according to Holladay of the preoperative spherical corneas yielded a with-the-wound change of 0.0 +/- 0.3 dpt after 3.2-mm incisions versus 0.6 +/- 0.7 dpt after 4.1-mm incisions. The difference in astigmatism for the two types of incisions was statistically significant (p = 0.001).

CONCLUSION

Acrysof lens implantation is especially useful for patients with spherical corneas because of avoidance of postoperative astigmatism. The 4. 1-mm corneal incision using PMMA lens implants can be used on the steep meridian to reduce preoperative astigmatism.

New Paradigm for the Treatment of Myopia By Refractive Surgery

It is proposed that refractive surgery visual outcomes will be significantly improved when using refractive surgery profiles that maintain preoperative corneal aberrations following surgery. An equation to calculate postoperative corneal shapes is presented.

Effect of disagreement between refractive, keratometric, and topographic determination of astigmatic axis on suture removal after penetrating keratoplasty

BACKGROUND/AIMS

Post-keratoplasty astigmatism can be managed by selective suture removal in the steep axis. Corneal topography, keratometry, and refraction are used to determine the steep axis for suture removal. However, often there is a disagreement between the topographically determined steep axis and sutures to be removed and that determined by keratometry and refraction. The purpose of this study was to evaluate any difference in the effect of suture removal, on visual acuity and astigmatism, in patients where such a disagreement existed.

METHODS

37 cases (from 37 patients) of selective suture removal after penetrating keratoplasty, were included. In the first group "the disagreement group" (n=15) there was disagreement between corneal topography, keratometry, and refraction regarding the axis of astigmatism and sutures to be removed. In the second group "the agreement group" (n=22) there was agreement between corneal topography, keratometry, and refraction in the determination of the astigmatic axis and sutures to be removed. Sutures were removed according to the corneal topography, at least 5 months postoperatively. Vector analysis for change in astigmatism and visual acuity after suture removal was compared between groups.

RESULTS

In the disagreement group, the amount of vector corrected change in refractive, keratometric, and topographic astigmatism after suture removal was 3.45 (SD 2.34), 3.57 (1.63), and 2.83 (1. 68) dioptres, respectively. In the agreement group, the amount of vector corrected change in refractive, keratometric, and topographic astigmatism was 5.95 (3.52), 5.37 (3.29), and 4.71 (2.69) dioptres respectively. This difference in the vector corrected change in astigmatism between groups was statistically significant, p values of 0.02, 0.03, and 0.03 respectively. Visual acuity changes were more favourable in the agreement group. Improvement or no change in visual acuity occurred in 90.9% in the agreement group compared with 73.3% of the disagreement group.

CONCLUSIONS

Agreement between refraction, keratometry, and topography was associated with greater change in vector corrected astigmatism and was an indicator of good prognosis. Disagreement between refraction, keratometry, and topography was associated with less vector corrected change in astigmatism, a greater probability of decrease in visual acuity, and a relatively poor outcome following suture removal. However, patients in the disagreement group still have a greater chance of improvement than worsening, following suture removal.

Correcting keratoconus with intracorneal rings

PURPOSE

To evaluate the potential of intrastromal corneal ring technology (Intacs, KeraVision) to correct keratoconus without central corneal scarring.

SETTING

Department of Ophthalmology, Brest University Hospital, Brest, France.

METHODS

In this prospective, noncomparative, interventional case series, Intacs segments were implanted in 10 keratoconic eyes with clear central corneas and contact lens intolerance after corneal pachymetry was checked. Segment thicknesses varied based on corneal topography analysis.

RESULTS

No intraoperative complications occurred. The mean follow-up was 10.6 months. Postoperative results revealed a reduction in astigmatism and spherical correction and an increase in topographical regularity and increased uncorrected visual acuity.

CONCLUSION

Intacs technology can reduce the corneal steepening and astigmatism associated with keratoconus.

Extracapsular cataract extraction with a sutureless incision for dense cataracts

PURPOSE

To evaluate the use of extracapsular cataract extraction (ECCE) via a sutureless incision for dense cataracts.

SETTING

Nagata Eye Clinic, Nara, Japan.

METHODS

This retrospective study comprised 51 eyes of 45 consecutive patients with dense cataracts who had ECCE with a sutureless incision between January 1996 and April 1998. A scleral incision from 6.0 to 8.5 mm was made at 12 o'clock or between 9 and 12 o'clock (oblique incision). Measures of outcome included postoperative visual acuity, surgically induced astigmatism (polar value method and vector analysis), complications, and changes in corneal endothelial cell density and morphology.

RESULTS

Self-sealing was achieved in 45 eyes (88.2%), but additional sutures were required in 6 (11.8%). Intraoperative complications included posterior capsule rupture in 3 eyes (5.9%) and iris prolapse in 2 (3.9%). Corneal flattening against the preoperative steep meridian was observed in the 12 o'clock incision group (0.24 diopter [D] +/- 1.23 [SD]) and in the oblique incision group (0.17 +/- 0.89 D). By vector analysis, the surgically induced vector was 1.41 +/- 0.72 D in the 12 o'clock incision group and 1.02 +/- 0.66 D in the oblique incision group. After surgery, the mean cell loss was 8.2% +/- 12.5%. There were no significant differences, however, between other preoperative and postoperative morphometric indexes.

CONCLUSION

This fast, safe, and inexpensive technique may be a viable treatment for dense cataracts with large, hard nuclei.

[Minimizing induction of astigmatism in preoperative spherical cornea a. by mini-incision surgery with foldable IOL and b. by corneal tunnel incision with limbal relaxing incision]

BACKGROUND

In case of a spheric cornea preoperatively the refractive effect of a clear corneal cataract incision is undesirable. We studied two actual techniques to minimize the surgically induced astigmatism.

PATIENTS AND METHODS

Temporal clear corneal incision was performed in 77 patients with practically spherical cornea (0.2 +/- 0.1 D). 27 patients with 4.1-mm clear corneal stretch incision and 5 mm PMMA lens implantation served as control. 25 further patients were operated on with the same technique, but 2 additional limbal relaxing incisions (LRI) of 0.55-mm depth and 8 mm length at 6 and 12 o'clock were performed. In 25 patients a foldable acrylic lens (Acrysof) was implanted through a 3.2-mm temporal clear corneal incision. Corneal topography results were evaluated in all patients by the Jaffe and the Holladay analysis.

RESULTS

The surgically induced astigmatism of 0.8 +/- 0.5 dpt in the control group was reduced to 0.4 +/- 0.3 dpt by LRI and by reduction of the incision size as well in the treatment groups. With-the-wound-change (WTW) in the Holladay analysis was 0.6 +/- 0.7 dpt in the control group and around 0 in the groups with astigmatism reducing techniques.

CONCLUSION

To preserve a spherical cornea in clear corneal-tunnel incision, compensating limbal relaxing incisions (LRI) or ultra-small incisions with foldable lens implantation should be performed.

Corneal dynamics after single interrupted suture removal following penetrating keratoplasty

PURPOSE

To evaluate corneal topographic changes after removal of a single interrupted suture in patients who underwent keratoplasty for keratoconus.

METHODS

Fifteen interrupted sutures in 15 eyes after keratoplasty were removed to control astigmatism in a prospective clinical study. Videokeratography using an EyeSys Corneal Analysis System was performed before suture removal, and 1 hour, 1 day, 1 week, and 2 to 4 weeks after suture removal. Changes in dioptric power and axis of the steepest and flattest semimeridians were evaluated.

RESULTS

The range of the dioptric change of the steepest semimeridian was from -0.43+/-0.34 D during the first hour to +0.70+/-0.39 D from 1 day to 1 week. The largest axis change of the steepest semimeridian (17.1 degrees+/-5.6 degrees, range 1 degree to 66 degrees ) occurred during the first hour (P = .006). The largest surgically induced vectorial change occurred during the first hour (16.10 @ 10.5 ), while relative stability of the steepest semimeridian was observed during the rest of the study period. Changes in power and axis of the flattest semimeridian were also demonstrated. A variety of topographic corneal patterns were demonstrated following suture removal, indicating unpredictable change of astigmatism.

CONCLUSIONS

The steepest semimeridian of the central 3-mm zone showed maximal vectorial change 1 hour following suture removal. Reciprocal changes occurred at the same time in the flattest semimeridian. The response of the corneal surface to suture removal is unpredictable and complex.

Nonmechanical corneal trephination with the excimer laser improves outcome after penetrating keratoplasty

OBJECTIVE

To assess the impact of nonmechanical trephination on the outcome after penetrating keratoplasty (PK).

DESIGN

Prospective, randomized, cross-sectional, clinical, single-center study.

PATIENTS

A total of 179 eyes of 76 females and 103 males, mean age at the time of surgery 50.6 +/- 18.5 (range, 15-83) years. Inclusion criteria were (1) time interval from October 1992 to December 1997; (2) one surgeon (GOHN); (3) primary central PK; (4) Fuchs dystrophy (diameter, 7.5 mm) or keratoconus (diameter, 8.0 mm); (5) graft oversize, 0.1 mm; (6) no previous intraocular surgery; and (7) 16-bite double-running diagonal suture.

INTERVENTION

In a randomized fashion, eyes were assigned either to trephination with the 193-nm Meditec excimer laser (manually guided beam in patients, automated rotation device of artificial anterior chamber in donors) along metal masks with eight orientation teeth/notches (EXCIMER: 53 keratoconus, 35 Fuchs dystrophy; mean follow-up, 37 +/- 16 months) or with a hand-held motor trephine (Microkeratron; Geuder) (

CONTROL

53 keratoconus, 38 Fuchs dystrophy; mean follow-up, 38 +/- 14 months). Subjective refractometry (trial glasses), standard keratometry (Zeiss), and corneal topography analysis (TMS-1; Tomey) were performed before surgery, before removal of the first suture (15.2 +/- 4.2 months), and after removal of the second suture (21.4 +/- 5.6 months).

MAIN OUTCOME MEASURES

Keratometric and topographic net astigmatism as well as refractive cylinder; keratometric and topographic central power; best-corrected visual acuity (VA); surface regularity index (SRI), surface asymmetry index (SAI), and potential visual acuity (PVA) of the TMS-1.

RESULTS

Before suture removal, mean refractive/keratometric/topographic astigmatism did not differ significantly between EXCIMER (2.5 +/- 1.8 diopters [D]/3.4 +/- 2.8 D/4.7 +/- 3.1 D) and CONTROL groups (3.0 +/- 1.8 D/3.7 +/- 2.4 D/4.3 +/- 2.1 D). After suture removal, respective values were significantly lower in the EXCIMER group (2.8 +/- 2.0 D/3.0 +/- 2.1 D/3.8 +/- 2.6 D) than in the CONTROL group (4.2 +/- 2.4 D/6.1 +/- 2.7 D/6.7 +/- 3.1 D) (P < 0.0009). In the EXCIMER versus CONTROL group, mean VA increased from 20/100 versus 20/111 (P > 0.05) before surgery, to 20/31 versus 20/38 before (P = 0.001) and to 20/28 versus 20/39 (P < 0.00001) after suture removal. Mean spherical equivalent was significantly less myopic in the EXCIMER group before (-0.9 +/- 3.6 D vs. -2.6 +/- 3.4 D) (P = 0.01) and after suture removal (-1.4 +/- 3.1 D vs. -2.4 +/- 3.5 D) (P = 0.02). Mean SRI (P = 0.04) and PVA (P = 0.007) were significantly more favorable in the EXCIMER versus CONTROL group after suture removal (0.91 +/- 0.45 and 0.82 +/- 0.15 vs. 1.05 +/- 0.46 and 0.73 +/- 0.18).

CONCLUSIONS

Postkeratoplasty results seem to be superior using nonmechanical excimer laser trephination. Thus, this methodology is recommended as the procedure of first choice in avascular corneal pathologies requiring PK.

Perforating keratoplasty with an intracorneal ring

PURPOSE

We evaluated the clinical feasibility of an intracorneal ring for penetrating keratoplasty (PKP) designed to decrease postoperative corneal astigmatism.

MATERIAL AND METHODS

A steel alloy ring was used for 8-mm PKP. The prospective study was comprised of 15 consecutive patients who underwent PKP for different corneal pathologies. The mean age was 52 years (range, 20-74 years). The Guided Trephine System was used in all cases for the preparation of the donor button and the recipient bed to ensure identical dimensions. The donor button with the surrounding ring in place was sutured in place with a 10-0 nylon double-running suture.

RESULTS

Except for one patient who had an allergic reaction to alloy components, no significant complications were observed. Mean reepithelialization occurred within an average of 4 days (range, 3-5 days). In 80% of the cases, stromal graft edema and Descemet's folds disappeared at 14 days after surgery. Average removal time of the intracorneal ring was 6 months (range, 3-9 months). Mean corneal astigmatism was 2.71 (standard deviation [SD], 1.37) diopters (D) before surgery compared to 2.10 (SD, 1.09) D at 1 month, 2.07 (SD, 1.26) D at 3 months, 2.29 (SD, 0.86) D at 6 months, and 2.94 (SD, 1.05) D at 12 months. In four eyes (27%), ruptures of one of the double-running antitorque sutures required resuturing.

CONCLUSION

The intracorneal ring prevented the donor button from distortions related to peripheral changes or suture traction. A sutured intracorneal ring appears to be a safe and effective aid in keratoplasties. Further evaluation in a multicenter study with larger patient numbers and indication-specific longer follow-ups is under way.

Asymmetric L-shaped corneal no-stitch tunnel incisions for cataract surgery

PURPOSE

To assess whether a unilateral asymmetric radial enlargement of a corneal tunnel incision for implantation of foldable intraocular lenses yields advantages over conventional linear enlargements.

SETTING

Department of Ophthalmology, University of Brussels, VUB, Belgium.

METHODS

Asymmetric corneal tunnel incisions with an L-shaped entrance and a concave exit were compared with equivalent conventional linear incisions in patients and in postmortem eyes.

RESULTS

The asymmetric no-stitch L-designs scored consistently better than the symmetric linear designs in induced astigmatism, postoperative astigmatic shift, complications, and pressure resistance.

CONCLUSION

An asymmetric corneal L-incision is superior to a conventional symmetric linear incision.

Customized and low spherical aberration corneal ablation design

PURPOSE

The purpose of this study was to use the Arizona Eye Model to help guide customization of corneal excimer ablation and reduce spherical aberration.

METHODS

Myopic eyes were treated with the Nidek EC-5000 excimer laser with a 5.5-mm diameter optic ablation zone and a 7.0-mm diameter transition ablation zone. We analyzed preoperative and postoperative corneal topographies using height mapping. From this data, refractive error profiles and maps were constructed using the Arizona Eye Model. The first group of patients had refractions between -2.00 and -5.00 D. Data was obtained by subtracting postoperative topography from preoperative topography. We then plotted the ideal ablation pattern if no additional spherical aberration was introduced when compared to preoperative topographies.

RESULTS

We found that in the central 4 mm, the ablation pattern was highly acceptable, with negligible spherical aberration. As the ablation moved out toward 6 mm, there was increasing spherical aberration. Newer ablation designs require more flattening in the midperiphery of the cornea. These flatter peripheral designs require more blending in the periphery and larger transition zones.

CONCLUSION

The use of computerized corneal topography in eye modeling is helpful in designing new ablation patterns to reduce optical and spherical aberration. Ablation zone design is critical to maximizing optical and biologic tolerance.

Refractive cataract surgery

Today, cataract surgeons can control postoperative refraction after cataract removal with improved intraocular-lens calculation formulas and minimal invasive surgery. However, a physiologically healthy status of the human lens (transparency, accommodation) cannot yet be regained completely postoperatively. Refractional outcome should be planned by the surgeon according to the patient's requirements. The preoperative planning also should include consideration of the intraocular-lens material needed.

Long-term results of single continuous suture adjustment to reduce penetrating keratoplasty astigmatism

PURPOSE

To evaluate the long-term effect of single continuous corneal suture adjustment on reducing penetrating keratoplasty astigmatism after suture removal.

METHODS

Patients were identified from the original study of single continuous penetrating keratoplasty suture adjustment to reduce corneal astigmatism who were followed for more than a year after suture removal. A matching unadjusted control group was selected in the same way from those patients in the original study undergoing penetrating keratoplasty during the 2 years before the development of suture adjustment. The corneal astigmatism was compared before adjustment (study group) or <3 months after surgery (control group), >4 months after suture adjustment, and >12 months after suture removal in both groups.

RESULTS

A study group of 54 patients with suture adjustment and a control group of 45 patients without suture adjustment were identified. Before suture adjustment, the study group had an average keratometric astigmatism of 6.44 diopters (standard deviation [SD] = 2.51, range = 0.38-12.25), and the control group had 6.38 diopters (SD = 3.29, range = 2.75-16.00, p = 0.536). Compared to that in the unadjusted control group, the average penetrating keratoplasty astigmatism in the suture-adjusted group was reduced by 44.6% (2.36 diopters) 4.5 months after surgery and before suture removal (p = 0.0002) and by 25.4% (1.19 diopters) at least 12 months after suture removal (p = 0.011).

CONCLUSION

Postoperative adjustment of a single continuous corneal suture significantly reduces penetrating keratoplasty astigmatism after suture removal.

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

OBJECTIVE

To compare postoperative astigmatism induced by two different suturing techniques in penetrating keratoplasty (PKP).

DESIGN

A monocenter, prospective, randomized clinical trial with a longitudinal 1-year follow-up.

PARTICIPANTS

A total of 95 eyes undergoing PKP were randomized into 2 groups. Of these, 51 eyes were allocated to the combined interrupted and continuous suturing group (ICS) and 44 eyes to the single continuous adjustable suturing (SCAS) group.

INTERVENTION

In the ICS group, suturing was with a combination of 12 interrupted 10-0 nylon and 1 continuous 11-0 nylon sutures. Eyes in the SCAS group had been sutured with a single running 24-bite 10-0 nylon. Selective suture removal started no earlier than 10 weeks after surgery; suture adjustment could start as soon as possible after surgery.

MAIN OUTCOME MEASURES

Astigmatism was measured by topography, keratometry, and refraction at 3-, 6-, 9-, and 12-month postoperative intervals.

RESULTS

The difference in mean time of suture manipulation between groups was significant (P = 0.0001), with the SCAS starting earlier. A significant decrease in astigmatism occurred by either interrupted suture removal (6.69 +/- 3.11 diopter [D] before to 4.76 +/- 2.99 D after, P = 0.0002) or suture adjustment (7.18 +/- 3.12 D before to 4.46 +/- 3.24 D after, P = 0.0001). However, the net astigmatic reduction in the SCAS group was not significantly greater (P = 0.250) than in the ICS group. Vector change was 7.40 +/- 4.17 D and 6.28 +/- 4.14 D for SCAS and ICS, respectively (P = 0.13). At no interval (3, 6, 9, or 12 months) was there significant difference in astigmatism between the two groups. Refractive astigmatism (cyl, D) at 1 year was 2.66 +/- 1.70 for the ICS and 3.12 +/- 2.62 for the SCAS, but there was no significant treatment effect (P = 0.945). Furthermore, 66% of the ICS eyes and 58% of the SCAS eyes (P = 0.295) were within the astigmatic target of the study (<3.5 D).

CONCLUSIONS

Postkeratoplasty astigmatism can be decreased similarly with either adjustment of a single running suture or selective removal of interrupted sutures. No advantage of the SCAS over ICS in terms of fewer manipulations or less astigmatism was seen as suggested previously.

Intraoperative versus postoperative suture adjustment after penetrating keratoplasty

PURPOSE

To study the effects of running suture adjustment for reduction of astigmatism after penetrating keratoplasty. Suture adjustments performed during surgery and during the early postoperative and late postoperative periods were retrospectively compared.

METHODS

We studied 53 patients who received running suture adjustment after penetrating keratoplasty, either intraoperatively (ISA group, n = 18), early (< 2 weeks) postoperatively (EPSA group, n = 19), or late (> 1 month) postoperatively (LPSA group, n = 16). Refractive and topographic astigmatism and corneal topography were examined at 1, 3, and 6 months after surgery.

RESULTS

Overall mean refractive astigmatism and topographic astigmatism at 6 months were 2.55 +/- 1.61 D and 3.12 +/- 1.89 D, respectively (mean +/- SD). The mean refractive astigmatism and topographic astigmatism were 1.88 +/- 1.04 D and 2.35 +/- 1.35 D in the ISA group, 2.32 +/- 1.17 D and 2.70 +/- 1.21 D in the EPSA group, and 3.01 +/- 1.62 D and 4.62 +/- 2.51 D in the LPSA group, respectively (mean +/- SD). The LPSA group demonstrated significantly increased topographic astigmatism compared to the ISA group (p = 0.0048) and the EPSA group (p = 0.015). Although 31.6 and 25.0% of the EPSA and LPSA groups, respectively, did not require postoperative suture adjustments, more eyes (10/18 eyes, 55.6%) in the ISA group did not require the procedure.

CONCLUSIONS

Early postoperative suture adjustment was more effective than late postoperative adjustment. Intraoperative suture adjustment may further reduce final astigmatism and the necessity for postoperative suture manipulation.

[The effect of corneal incision method on astigmatism after cataract extraction]

PURPOSE

To assess the effect of the type of corneal incision and its closure on astigmatism after cataract extraction.

MATERIAL AND METHODS

Induced astigmatism was evaluated in 94 eyes after cataract extraction with IOL implantation 7 days, 1 month, 3 months, 6 months and 12 months after operation. 3 groups: were compared I--after extracapsular extraction with corneo-scleral incision (10 h-2 h) and continuous cross-like suture, II--after phacoemulsifications with scleral tunnel incision (3.3 mm) without suture.

RESULTS

The highest induced astigmatism was observed 7 days after surgery in patients with the longest corneo-scleral incision with suture (group I). Induced astigmatism gradually decreased in time. In group after phacoemulsification especially with no suture low astigmatism with prompt stabilization was observed.

CONCLUSIONS

The length and type of closure of the incision have an essential effect on induced astigmatism. Small incision, especially without suture induces minimal early postoperative astigmatism which remains stabile.

Postoperative suture manipulation for control of corneal graft astigmatism

PURPOSE

To assess the effect on post-keratoplasty astigmatism of postoperative manipulation of a single running suture.

METHODS

All corneal transplant patients in whom a single 10/0 nylon running suture was placed between November 1990 and April 1996 were included in a prospective study of the effect of manipulation of the suture at the earliest possible time after surgery when the keratometry became possible by virtue of the epithelial surface integrity and where this revealed astigmatism of greater than 2 D.

RESULTS

One hundred and ninety eyes underwent suture manipulation and were followed up. Follow up on 30 eyes was discontinued. Repeat manipulation of the running suture was the most common reason for discontinuation of follow up. The remaining patients were followed for a mean (+/- SD) 415.5+/-326.4 days. Mean astigmatism of 7.8+/-3.1 D was reduced to 1.7+/-2.0 D immediately after manipulation, but regressed to 3.0+/-1.9 D (n = 76) by 1 year. The suture was removed in 32 patients. Twenty-five eyes had post-removal astigmatism measurements. In these 25 eyes, astigmatic error appeared not to revert to premanipulation levels. The only significant complication was one broken suture at manipulation.

CONCLUSIONS

Early suture manipulation is effective in reducing suture in post-keratoplasty astigmatism, but some regression is seen.

A new surgical technique for deep lamellar keratoplasty with single running suture adjustment

PURPOSE

To improve the technique of deep lamellar keratoplasty.

METHODS

For the recipient eye, a divide-and-conquer technique was applied to deep lamellar keratoplasty. After trephinization, the recipient cornea within the trephine was divided into four quadrants to facilitate lamellar dissection at approximately 70% depth. This procedure of division was continued until the Descemet membrane was exposed in the central area. The corneal graft was placed with an adjusted single running suture. Seventeen eyes were treated with this technique.

RESULTS

In 17 eyes of 15 patients, the mean visual acuity 6 months or more after deep lamellar keratoplasty was 20/52 with eyeglass correction and 20/80 without eyeglass correction. At 6 months or more after deep lamellar keratoplasty, the mean +/- SD keratometric astigmatism in 17 eyes was 3.2 +/- 2.3 diopters.

CONCLUSION

This technique facilitates deep lamellar keratoplasty and prevents high or excessive astigmatism after surgery.

Different suturing techniques variously affect the regularity of postkeratoplasty astigmatism

OBJECTIVE

This study aimed to determine the effect of various suturing techniques on the regularity of postkeratoplasty astigmatism.

DESIGN

A prospective clinical trial.

PARTICIPANTS

Sixty-two consecutive patients undergoing penetrating keratoplasty by the same surgeon (MB) participated.

INTERVENTION

Each patient was assigned to one of four groups according to the suturing technique used (a = 16 interrupted 10-0 nylon sutures; b = 2 running 10-0 nylon sutures, each with 8 bites; c = 2 running 10-0 nylon sutures, each with 12 bites; d = 2 running 10-0 nylon sutures, each with 16 bites). This was the only parameter permitted to be changed in the standard keratoplasty procedure used for all cases. Corneal topography was performed 1, 3, and 6 months after surgery. The astigmatic patterns seen on the corneal maps then were classified into regular (symmetric or asymmetric bowtie patterns) or irregular (distorted bowtie, multiaxial, or other patterns).

MAIN OUTCOME MEASURES

Regularity of postkeratoplasty corneal astigmatism was measured.

RESULTS

At all postoperative examination times, the percentage of irregular astigmatic patterns was highest in group a and lowest in group d (chi-square test: P < 0.005). Groups b and c showed intermediate values. The entity of the astigmatic error as measured by the simulated K-readings of the topographic maps did not differ significantly in the four groups.

CONCLUSIONS

A suturing technique using 2 running sutures with 16 bites each can minimize irregular postkeratoplasty astigmatism as long as sutures are in place, when compared with interrupted sutures or double-running sutures of less than 16 bites.