Astigmatismus nach Keratoplastik

Background

Patients undergoing corneal transplantation often suffer from postoperative reduced vision due to high astigmatism. This retrospective study analyzed the influence of heterotopic or orthotopic transplantation on astigmatism and visual outcome.

Patients and methods

In this study 373 eyes of 334 patients were analyzed. Group 1 (OT) contained 186 eyes, which underwent orthotopic transplantation (side of recipient and donor corresponded), whereas group 2 (HT) included 187 heterotopic keratoplasties (donor cornea placed in the recipient’s contralateral side). After 1, 3, 6, 12 and 24 months the median of keratometric astigmatism, objective astigmatism, topographic astigmatism and best corrected visual acuity (BCVA) were assessed and compared between groups.

Results

The long-term results showed no statistically significant differences regarding keratometric and objective astigmatism, whereas topographic astigmatism differed significantly (p?=?0.04) after 3 months. We observed a lower astigmatism of 5.7 dpt (range 3.08-7.78 dpt) in group OT than in the group HT with 7.1 dpt (range 3.9-10.7 dpt). No differences were found at the other time points. The BCVA showed a significantly better effect after 1 month (p?=?0.01) in the OT group of 0.2 (0.1-0.3) than in HT group of 0.1 (0.05/0.25). In the postoperative course no additional significant dissimilarities were documented.

Conclusions

Heterotopic and orthotopic keratoplasty show no significant long-term differences in astigmatism and visual outcom.     

Astigmatismus nach perforierender Keratoplastik

Purpose

The aim of this study was a retrospective analysis of postkeratoplasty astigmatism and best corrected visual acuity (BCVA) in patients following penetrating keratoplasty (PK) and a comparison of three suturing techniques.

Patients and methods

In this retrospective analysis penetrating keratoplasty (PK) was carried out on 150 eyes with 3 suturing techniques: single running (SR), double running (DR counterclockwise) and interrupted (IR) sutures. Of the eyes 37 (24.7%) underwent PK with SR sutures, 81 eyes (54%) with DR sutures and 32 eyes (21.3%) had IR. PK for Fuchs?? dystrophy was used on 46 eyes (30.7%), on 33?eyes (22%) for keratoconus, on 12 eyes (8%) for herpetic keratitis and on 7 eyes (4.6%) for pseudophakic bullous keratopathy. For trephination a guided trephine system (GTS) was used in 44%, rotortrepan in 46.6% and best trepan in 5.3%. Postkeratoplasty astigmatism and best corrected visual acuity (BCVA) were evaluated 1, 4, 12 and 24 months after surgery (all sutures removed). Subjective and objective refractions and corneal topography were performed to assess astigmatism. The Kolmogorov-Smirnov test (95% significance) was used to evaluate statistical significance.

Results

Mean topographic astigmatism 4 months (12 months/2 years) after keratoplasty was 4.9?dpt (5.3/4.1, n=4) for SR, 4.2?dpt (4.0/5.3) for DR and 9.7?dpt (n=7) (4.9, n=8/6.8, n=2) for IR suturing techniques. Mean objective astigmatism 4 months (12 months/2 years) after PK was 5.9?dpt (4.1, n=7/5.0, n=3) for SR, 3.4?dpt (4.5/4.98) for DR and 8.0?dpt (n=3) (6.9, n=4/7.4, n=2) for IR sutures. Mean refractive cylinder 4 months (12 months/2 years) after keratoplasty was 4.5?dpt (3.9/4.9) for SR, 3.2?dpt (3.3/3.6) for DR and 6.2?dpt (3.7/4.7) for IR suturing. Mean BCVA 4 months (12 months/2 years) was 0.3 (0.3/0.4) for SR, 0.3 (0.4/0.5) for DR and 0.3 (0.4/0.4) for IR sutures. BCVA 4 months (12 months/2 years) after PK (GTS only) reached 0.3 (0.3/0.5) for SR and 0.3 (0.4/0.6) for DR suturing.

Discussion

Topographic and objective astigmatisms were highest for the IR suturing technique. Topographic astigmatism and refractive cylinder were less in the DR (compared to SR) group 4 and 12 months after surgery (statistically significant). After suture removal (2 years after PK) refractive cylinder was still lower for DR compared to SR but there was no statistical difference between DR and SR regarding topographic and objective cylinders. For the interpretation of these data it should be emphasized that due to the retrospective character of this analysis the number of patients in the subgroups is decreasing with time and as a consequence single (strongly deviating) measurements can have a more powerful impact on the outcome in the individual subgroups.     

Clinical results of 123 femtosecond laser-assisted penetrating keratoplasties

Background

Postoperative astigmatism following penetrating keratoplasty is a major problem after corneal transplantation. The main goal of new trephination techniques such as femtosecond laser or excimer-laser trephination is to improve refractive and visual outcomes. The femtosecond laser technique makes profiled corneal trephinations such as the top hat or mushroom profile possible. We present the postoperative outcome of femtosecond laser-assisted penetrating keratoplasties.

Methods

We performed 123 femtosecond laser-assisted penetrating keratoplasties in 119 patients. The main outcome measures were intraoperative specifics, astigmatism, and irregularity in Orbscan corneal topography, as well as the occurrence of immune reactions and side-effects.

Results

All sutures have been removed in 49 of these 123 eyes. Their mean follow-up was 13.9?±?4.5 months. Time to complete suture removal (n?=?49) was 12.0?±?3.7 months in the mushroom group and 9.8?±?2.1 months in the top hat group. Mean astigmatism in Orbscan topography was 6.4?±?3.0 diopters in the mushroom and 5.8?±?4.6 diopters in the top hat group (all sutures out).

Conclusions

Femtosecond laser-assisted penetrating keratoplasty is a safe surgical technique. Due to the steps in profiled trephinations, the wound area is larger and theoretically the wound healing is, thus, faster and more stable. Complete suture removal is possible at an earlier time point compared to conventional penetrating keratoplasty. However, refractive results are not superior to those following conventional trephination.     

Intrakorneale Ringsegmente beim Keratokonus

Introduction

The spectrum of stage-related therapy of keratoconus has been broadened through surgical implantation of intracorneal ring segments (INTACS) as a possible method of reducing irregular astigmatism, leading to a reduction of corneal grafts especially in young, working-aged patients with keratoconus. The purpose of the present study was to evaluate the preoperative and postoperative results of femtosecond laser-assisted implantation of INTACS in ectatic corneal diseases.

Patients and methods

From August 2011 to January 2013, 20 eyes from 16 patients with a clear cornea in the visual axis suffering from hard contact lens intolerance underwent surgery in the Homburg/Saar Keratoconus Center (HKC) by the same surgeon (MEH). Among these were 16 keratoconus eyes, 1 eye with pellucid marginal degeneration und 3 eyes with post-LASIK iatrogenic keratectasia. The insertion of the INTACS ring segments was achieved by a femtosecond laser-assisted procedure that created a precise 360° tunnel at a depth of 80?% of the corneal thickness (395.8?±?38.5 μm) in the 6–7 mm zone.

Results

At 6 months follow-up mean uncorrected distance visual acuity improved from 0.07?±?0.07 preoperatively to 0.6?±?0.26 postoperatively. Mean best-corrected distance visual acuity changed from 0.4?±?0.15 preoperatively to 0.9?±?0.29 postoperatively. Mean sphere decreased from ??7.6?±?6.1 dpt to ??1.4?±?2.8 dpt. Astigmatism decreased from ??6.0?±?2.8 dpt preoperatively to ??4.3?±?2.0 dpt postoperatively. There was also a reduction in the mean flat K from 47.8?±?4.7 dpt preoperatively to 44.2?±?5.0 dpt postoperatively and in mean steep K from 51.9?±?5.0 dpt to 48.4?±?6.6 dpt. The central eccentricity index in the Pentacam was reduced to around 50?%. Neither intraoperative nor postoperative complications (including non-responders) were observed.

Conclusions

The femtosecond laser-assisted INTACS implantation provides a valid alternative to early keratoplasty for keratoconus patients with a clear central cornea and contact lens intolerance. It is a minimally invasive and reliable method for stage-related surgical management of keratoconus.     

Long-term results of penetrating keratoplasty with different trephine systems -- a clinical investigation from the university eye hospital of halle/saale and the eye clinic of the helios hospital aue

BACKGROUND: The results of penetrating keratoplasty in two centres for cornea transplantation were investigated with regard to the following parameters: the trephine system used, the origin of the donor cornea, the influence on the postoperative astigmatism and other aspects. PATIENTS AND METHODS: The retrospective clinical investigation reports about the results of 186 patients with penetrating keratoplasty from the University Eye Hospital of Halle and 204 patients from the Eye Clinic of the Helios hospital Aue. RESULTS: Three trephine systems have been used: the Hessburg-Barron trephine, the guided trephine system (GTS) and the Asmotom device. There were no significant differences between them concerning visual acuity after 12 months postoperatively. The results were highly significantly better (p = 0.003 Halle; p = 0.001 Aue) when using larger diameters of the trephine (7.5 mm and 8.0 mm). The origin of the donor cornea ("fresh" cornea from a deceased subject or organ cultivated cornea from a cornea bank) had no influence on visual outcome after twelve months (p > 0.8). There were less wound dehiscences using the double running suture in comparison with other techniques (p = 0.05). The removal of suturing material was not effective in reducing postoperative astigmatism (p > 0.11). There was no increase in astigmatism when leaving the sutures in situ (p > 0.25). CONCLUSIONS: Generally, each of the three trephine systems can be recommended for clinical use. The trephination should be done with trephine diameters of 7.5 mm or 8.0 mm. A timely operation guarantees better visual acuity at one year postoperatively.     

Ipsilaterale Autorotationskeratoplastik und Kataraktextraktion bei Patienten mit vernarbendem Trachom in Oman

Aim

To report on the results of visual rehabilitation by ipsilateral rotational keratoplasty (IRK) and cataract extraction in 17 patients with trachoma and with trachoma and trauma in Oman over 3 years.

Patients

Of 25 patients operated from 2001–2004 with IRK, extracapsular cataract extraction, and intraocular lens implantation, 17 eyes of 17 patients with cicatricial trachoma (WHO stage CO) could be followed up after 1 year. Group 1 comprised 11 eyes with ciatricial trachoma. In group 2, six eyes had additional traumatic corneal scars.

Methods

Surgery was performed using a motor trephine Keratron (Geuder), the Accurus 800 (Alcon) phacovitrectomy machine, and calculation for intraocular lens implantation (IOL: MZ60BD, Alcon) with a topography (Atlas, Humphrey Zeiss)-supported SRK II formula (OcuScanRxP, Alcon).

Results

Although only four of 17 patients had preoperative visual acuity (VA) at 5 m and one of 17 had VA at 1 m, postoperatively seven of 17 patients gained VA at 5 m and six of 17 at 1 m. Ambulatory vision was regained in 13 of 17 (78%) patients. Patients with trachoma and trauma benefited more from the surgery [vision increase in trachoma: eight of 11 eyes (73%); trachoma and trauma: five of five eyes (100%)]. Postoperative spherical refraction was -12.0D to +4.0D (median:+4.0D), and astigmatism ranged from 10D to 0.3D (median 5.35D). One eye was lost because of uncontrolled keratitis.

Conclusions

IRK with cataract extraction may provide ambulatory vision in patients with cicatricial trachoma and secondary dry eye syndrome living in developing countries where donor grafts are difficult to obtain and where postoperative follow-up of high-risk keratoplasty is impaired.     

Partial lamellar keratoplasty for peripheral corneal disease using a graft from the glycerin-preserved corneoscleral rim

Background

To evaluate the feasibility of partial lamellar keratoplasty (LK) for treatment of peripheral corneal disease (PCD) using a graft from the corneoscleral rim preserved in glycerin.

Methods

Patients who underwent LK for PCD at Shandong Eye Hospital from January 2006 to December 2012 were included. Corneoscleral rims of donor grafts, out of which the corneal buttons had been punched and used for penetrating keratoplasty, were preserved in glycerin and used for LK procedures. A trephine of 7.5–8.0 mm was used to mark the central cornea. An excision was made according to the size of the lesions, after which a partial ring-shaped corneoscleral graft was transplanted to repair the peripheral cornea. Visual acuity, refractive astigmatism, and complications were monitored.

Results

There were 26 patients (28 eyes), including 15 patients with Terrien’s marginal degeneration, eight with Mooren’s ulcer, two with Wegener’s granulomatosis, and one with peripheral corneal ulcer. The mean follow-up was 15 months (range, 6–36 months). Uncorrected visual acuity was improved by a mean of 3.17 Snellen chart lines (P?=?0.010), and best spectacle-corrected visual acuity was improved by a mean of 0.85 Snellen chart lines (P?=?0.045) at 6 months after surgery. The refractive astigmatism decreased by 5.1?±?8.6 diopters (P?=?0.003). Two patients suffering graft ulcers (recurrence) were successfully treated by a second partial LK. No graft rejection occurred.

Conclusions

Partial LK using a graft from the corneoscleral rim appears to be effective in the treatment of patients with PCD. This approach saves the donor graft, which is important in the countries or regions with scarcity of donor tissue.     

Einfluss der Spenderlamellendicke auf die Sehschärfe nach „Descemet’s stripping automated endothelial keratoplasty“ (DSAEK)

Background

The aim of this study was to evaluate the effect of donor lamella thickness on postoperative visual acuity after Descemet’s stripping automated endothelial keratoplasty (DSAEK).

Materials and methods

A retrospective analysis of 65 eyes from 61 patients who underwent DSAEK surgery in cases of Fuchs’ corneal dystrophy or bullous keratopathy between 2008 and 2011 was performed. The thickness of donor lamella was measured intraoperatively by ultrasonic pachymetry and postoperatively by anterior segment optical coherence tomography (OCT) and correlated to the visual acuity and number of endothelial cells.

Results

The donor lamella thickness measured intraoperatively and postoperatively correlated significantly with each other (r?=?0.874, p?<?0.001). A significant correlation was found between postoperative corneal lamella thickness measured by anterior segment OCT and visual acuity (r?=?0.273, p?=?0.028) but not between intraoperative donor lamella thickness measured by ultrasonic pachymetry and visual acuity (r?=?0.241, p?=?0.103). The postoperative endothelial cell number did not show a correlation with either the intraoperatively or the postoperatively measured donor lamella thickness (r?=???0.059, p?=?0.731, r?=?0.024, p?=?0.869, respectively).

Conclusions

Corneal lamella thickness <?120 µm was found to be correlated with a better visual outcome than in cases of thicker corneas >?120 µm. Despite greater difficulty in corneal transplant technique in cases of thinner lamella no increased damage of corneal endothelium was shown. Therefore, DSAEK with corneal lamella thickness <?120 µm is an interesting therapeutic alternative to DMEK.     

DALK und perforierende Laserkeratoplastik bei fortgeschrittenem Keratokonus

Background

In cases of contact lens intolerance and/or central corneal scars, corneal transplantation is indicated for advanced keratoconus. This can be performed as deep anterior lamellar keratoplasty (DALK) or as penetrating keratoplasty (PKP). The German keratoplasty registry shows that the proportion of anterior lamellar grafts in Germany has remained stable at approximately 5?% in recent years.

Methods

Up to now DALK has not been technically standardized but can result in a good visual acuity using the big bubble technique if Descemet’s membrane is laid bare intraoperatively. In 10–20?% a conversion to PKP is required if perforation of Descemet’s membrane occurs. In cases of advanced keratoconus PKP is still the method of first choice especially after corneal hydrops due to rupture of Descemet’s membrane. Non-contact excimer laser trephination seems to be especially beneficial for eyes with iatrogenic keratectasia after LASIK and those with repeat grafts in cases of keratoconus recurrence due to the graft being too small. For donor trephination from the epithelial side, an artificial chamber is used. Wound closure is achieved by a double running cross-stitch suture according to Hoffmann. Graft size is adapted individually depending on corneal size (as large as possible and as small as necessary). Limbal centration is given priority intraoperatively due to optical displacement of the pupil.

Results

Prospective clinical studies have shown that the technique of non-contact excimer laser PKP improves donor and recipient centration, reduces vertical tilt and horizontal torsion of the graft in the recipient bed, thus resulting in significantly less all-sutures-out keratometric astigmatism (2.8 D versus 5.7 D), higher regularity of the topography (SRI 0.80 vs. 0.98) and better visual acuity (0.80 vs. 0.63) in contrast to the motor trephine. The stage of the disease does not influence functional outcome after excimer laser PKP.

Conclusions

In cases with optimal course DALK achieves the same visual outcome as mechanical PKP but the healthy endothelium can be preserved and endothelial immune reactions are prevented in keratoconus. In contrast to the undisputed clinical advantages of excimer laser keratoplasty with orientation teeth/notches in keratoconus, the major disadvantage of femtosecond laser application is still the necessity of suction and applanation of the cone during trephination.     

Visual outcomes and complications following posterior iris-claw aphakic intraocular lens implantation combined with penetrating keratoplasty

Background

To evaluate the indication, visual outcome, and complication rate after implantation of a posterior iris-claw aphakic intraocular lens (IOL) during penetrating keratoplasty.

Methods

This retrospective study comprised 23 eyes (23 patients) without adequate capsule support undergoing posterior iris-claw aphakic IOL implantation (Verisyse?/Artisan®) during penetrating keratoplasty between 2005 and 2010. Mean follow-up was 18 months (range from 12 to 37 months).

Results

The IOLs were inserted during an IOL exchange in 17 eyes and as a secondary procedure in six aphakic eyes. Pseudophakic bullous keratopathy with corneal scar after anterior chamber intraocular lens (ACIOL) was the main indication for penetrating keratoplasty in 16 eyes (69.6 %). The final corrected distance visual acuity (CDVA) in logMAR (mean 1.0?±?0.46) improved significantly (p?<?0.05) compared to the preoperative CDVA (mean 1.8?±?0.73). Twenty eyes (86.9 %) had a final visual acuity in logMAR better than the pre-operative CDVA. The mean postoperative IOP 16.3 mmHg?±?4.0 was not significantly (p?>?0.05) higher compared to the preoperative IOP 15.6 mmHg?±?5.1. Complications included slight temporary pupil ovalization in three eyes (13.0 %) and iris-claw IOL sublocation in three eyes (13.0 %); all IOLs could be easily repositioned. Cystoid macular edema occured in one eye (4.3 %) 8 weeks after primary surgery. All grafts remained clear without any sign of graft rejection.

Conclusions

Retropupillar iris-claw IOL during penetrating keratoplasty provides good visual outcomes with a favorable complication rate, and can be used for a wide range of indications in eyes without adequate capsule support.     

Evaluation of graft–host interface after penetrating keratoplasty using anterior segment optical coherence tomography

Purpose

To evaluate the characteristics of the graft–host interface after penetrating keratoplasty (PKP) using anterior segment optical coherence tomography (AS-OCT).

Methods

Forty-nine eyes of 49 patients with three different underlying diseases (corneal scar, 22 eyes; bullous keratopathy, 14 eyes; keratoconus, 13 eyes) who underwent PKP were retrospectively reviewed. AS-OCT was performed in all patients and wound profiles of the graft–host junctions were classified into well-apposed junction, gap, step, and protrusion. The correlations between clinical characteristics and wound profiles from the AS-OCT were analyzed.

Results

A total of 392 graft–host junctions from 49 eyes were analyzed. Among them, 155 sections (39.5 %) had well-apposed junctions and 237 sections (60.5 %) had malapposed junctions. The most frequent type of malapposition was protrusion (117 sections, 39.9 %). When categorizing the eyes according to the most frequent alignment type among the 8 cross-sections, the alignment pattern showed significant differences between the preoperative diagnosis groups (P = 0.04). Spherical equivalent (P = 0.04) and keratometric astigmatism (P < 0.01) showed significant differences between the alignment groups. Graft–host thickness disparities showed significant correlations with keratometric astigmatism (r = 0.56, P < 0.01) and degree of graft oversize (r = 0.29, P = 0.04).

Conclusions

The alignment pattern of wound interface after PKP differed according to the clinical diagnosis before surgery and was significantly associated with spherical equivalent and keratometric astigmatism.     

Biometrie in Katarakt-Camps

Background

Biometry has the potential to improve refractive outcomes of cataract surgery in developing countries. However, the procedure is difficult to carry out in remote areas.

Patients and methods

The feasibility of automated biometry using portable devices was assessed in an eye camp in a remote Kenyan community and reasons for failure were documented. PC-IOLs in the range of 17–27 dioptres (dpt) were implanted and a model was created to predict spherical refractive error if a standard 22 dpt lens had been used.

Results

In 104 out of 131 eyes (80%) biometry was possible. Failure to obtain K-readings in eyes with coexisting corneal pathology was the main limiting factor. The calculated mean IOL strength to achieve emmetropia was 21.56 dpt with a SD=1.96 (min: 14.78 dpt, max: 27.24 dpt). If 22dpt lenses had been implanted around 20% would have had an error of more than 2 dpt and 7% an error of more than 3 dpt.

Conclusion

Biometry is a challenging procedure in remote areas where comorbidities are common. However, without biometry and implantation of different IOL powers poor refractive outcome can be expected in around 20% of patients.     

Postmortale Evaluation des kornealen Astigmatismus nach Astigmatismus-orientierter perforierender Keratoplastik (AOpKP)

Background. Reduction of astigmatism following penetrating keratoplasty can be achieved if the graft is oriented according to astigmatism parameters in donor and host (AOPKP). Postmortem evaluation of these parameters is therefore essential. The aim of our investigation was to compare postmortem measurements using a hand-held keratometer with those of the living donor's astigmatism. Method. The 72-year-old female patient had underrgone AOPKP on her right eye. After death the astigmatism in the right eye was evaluated 4.5 h postmortem using a hand-held keratometer. After explantation, the eyeball was examined by computer-assisted topography (TMS-1). Results/Conclusion. We could show that hand keratometry in situ is reliable for evaluating astigmatism in donor eyes after death. As far as our AOPKP study is concerned, these results are of great interest. Reduction of postoperative astigmatism following penetrating keratoplasty is only possible if data on astigmatism of the donor and host corneas are available.     

Visual outcome and histological findings following femtosecond laser-assisted versus microkeratome-assisted DSAEK

Background

The aim of this study was to compare the visual outcome of femtosecond laser-assisted Descemet stripping automated endothelial keratoplasty (DSAEK) to microkeratome-assisted DSAEK as well as to contrast precut versus surgeon-cut grafts. Histologic characterization of failed DSAEK grafts was performed in order to correlate ultrastructural changes with graft failures.

Methods

In this case control study, 47 cases of DSAEK were investigated in terms of visual acuity, keratometric astigmatism, spherical equivalent, endothelial cell count, and postoperative complications. We formed three groups: the femtosecondlaser-assisted DSAEK with precut grafts, the microkeratome-assisted DSAEK with precut and with surgeon-cut grafts. Mean follow-up was 6 months. In the case of graft failure, penetrating keratoplasty was performed, and the excised corneal buttons were investigated by light and electron microscopy.

Results

Microkeratome-assisted DSAEK lead to better visual outcome than femtosecond laser-assisted DSAEK. Keratometric astigmatism, spherical equivalent and endothelial cell count did not differ significantly between both methods. Precut and surgeon-cut grafts in microkeratome-assisted DSAEK did not show any significant difference regarding all upraised parameters. No definite histological correlate for graft failure following femtosecond laser-assisted DSAEK was found.

Conclusions

Femtosecond laser-assisted DSAEK is not the method of choice, and needs further technical improvement. However, failed femtosecondlaser-assisted DSAEK grafts did not show significant histological changes related to the technique to explain reduced visual acuity. In microkeratome-assisted DSAEK, the preparation time point of the graft does not seem to influence the visual and optical outcome.     

Descemet's stripping endothelial keratoplasty (DSEK) for children with congenital hereditary endothelial dystrophy: surgical challenges and 1-year outcomes

Purpose

To evaluate the outcomes of Descemet's stripping endothelial keratoplasty (DSEK) in patients with congenital hereditary endothelial dystrophy (CHED).

Methods

Retrospective, interventional case series of five eyes of five patients with congenital hereditary endothelial dystrophy (CHED) undergoing Descemet's stripping endothelial keratoplasty (DSEK) from June 2009 to June 2010 by a single surgeon. Patients were evaluated during the postoperative period for visual acuity, refraction, corneal clarity, lenticule status, and intraocular pressure. Anterior segment ocular coherence tomography (OCT) and confocal microscopy were performed when possible.

Results

Three male and two female children with an average age of 7.8?years (range 5–12?years) with CHED underwent DSEK. Surgery was uneventful in all patients and the lenticules stayed attached during the postoperative period. All the patients had 1-year follow-up. Corneal clarity improved in all the patients over the period of follow-up. Anterior segment OCT showed a gradual reduction in the thickness of the central corneal thickness and the graft over a period of time.

Conclusions

DSEK is a viable alternative to penetrating keratoplasty in patients with CHED with distinct advantages of reduced postoperative astigmatism and potential reduction of postoperative complications.     

The impact of tear functions on visual outcome following keratoplasty in eyes with keratoconus

Background

To investigate the impact of preoperative and postoperative tear functions on visual outcome and the recovery of visual function following keratoplasty in eyes with keratoconus.

Methods

Twenty-five eyes of 25 consecutive patients (5 females, 20 males, mean age: 34.3?±?15.8 years (range: 19–70 years) with keratoconus who underwent either penetrating keratoplasty (PKP) or deep anterior lamellar keratoplasty (DALK) were included in this prospective study. One patient who had a rejection episode during the follow-up period was excluded. All subjects underwent best corrected visual acuity (BCVA), corneal topography (refractive cylinder, surface regularity index: SRI and surface asymmetry index: SAI), Schirmer I test, tear film break-up time (BUT), corneal sensitivity, and fluorescein staining score measurements before as well as 1, 3, 6 and 12 months after keratoplasty. The relation between the tear functions and the duration until the achievement of maximum BCVA was also evaluated. Linear regression analysis was performed to study the statistical significance of the correlations and the time wise change of each examined parameter.

Results

SRI, SAI, and BCVA significantly improved after keratoplasty. The postoperative corneal sensitivity was still significantly low even at 12 months postoperatively. Postoperative BCVA at 3, 6 months and maximum BCVA showed a significant linear negative correlation with the preoperative BUT (3 months; r?=??0.461, p?=?0.036, 6 months; r?=??0.494, p?=?0.023, maximum BCVA; r?=??0.473, p?=?0.030). The duration until the achievement of maximum BCVA showed a significant negative correlation with the preoperative Schirmer test (r?=??0.429, p?=?0.036). BCVA at 1 and 3 months postoperatively showed significant linear negative correlations with BUT value at the respective periods (1 month; r?=??0.665, p?=?0.0036, 3 months; r?=??0.580, p?=?0.0059).

Conclusion

Preoperative tear functions appeared to have an influence on postoperative BCVA and the duration of visual recovery in keratoconus patients undergoing keratoplasty. Postoperative tear film stability appears to play an important role for obtaining a better BCVA in the early postoperative period after keratoplasty.     

Analysis of internal astigmatism and higher order aberrations in eyes implanted with a new diffractive multifocal toric intraocular lens

Background

To evaluate the intraocular lens (IOL) position by analyzing the postoperative axis of internal astigmatism as well as the higher-order aberration (HOA) profile after cataract surgery following the implantation of a diffractive multifocal toric IOL

Methods

Prospective study including 51 eyes with corneal astigmatism of 1.25D or higher of 29 patients with ages ranging between 20 and 61 years old. All cases underwent uneventful cataract surgery with implantation of the AT LISA 909 M toric IOL (Zeiss). Visual, refractive and corneal topograpy changes were evaluated during a 12-month follow-up. In addition, the axis of internal astigmatism as well as ocular, corneal, and internal HOA (5-mm pupil) were evaluated postoperatively by means of an integrated aberrometer (OPD Scan II, Nidek).

Results

A significant improvement in uncorrected distance and near visual acuities (p?<?0.01) was found, which was consistent with a significant correction of manifest astigmatism (p?<?0.01). No significant changes were observed in corneal astigmatism (p?=?0.32). With regard to IOL alignment, the difference between the axes of postoperative internal and preoperative corneal astigmatisms was close to perpendicularity (12 months, 87.16°?±?7.14), without significant changes during the first 6 months (p?≥?0.46). Small but significant changes were detected afterwards (p?=?0.01). Additionally, this angular difference correlated with the postoperative magnitude of manifest cylinder (r?=?0.31, p?=?0.03). Minimal contribution of intraocular optics to the global magnitude of HOA was observed.

Conclusions

The diffractive multifocal toric IOL evaluated is able to provide a predictable astigmatic correction with apparent excellent levels of optical quality during the first year after implantation.     

Die perforierende Keratoplastik

Ten precautions for prophylaxis of astigmatism in penetrating keratoplasty are recommended:

1. The attempt should be made to determine donor topography for exclusion of previous refractive surgery, keratoconus/high astigmatism, and to allow for “harmonization” of donor and recipient topography.
2. Donor and recipient trephination should be performed from the epithelial side with the same system, which is the prerequisite for congruent cut surfaces and angles in donor and recipient. For this purpose an artificial anterior chamber is used for donor trephination.
3. Orientation structures in donor and host facilitate the correct placement of the first four or eight cardinal sutures to avoid horizontal torsion.
4. A measurable improvement seems to be possible, using the Krumeich guided trephine system (GTS), the second generation Hanna trephine, and the Erlangen technique of nonmechanical trephination with the excimer laser.
5. Horizontal positioning of the head and limbal plane are indispensable for state-of-the-art PKP surgery in order to avoid decentration, vertical tilt, and horizontal torsion.
6. Graft size should be adjusted individually (“as large as possible, as small as necessary”).
7. Limbal centration should be preferred over pupil centration (especially in keratoconus).
8. Excessive graft over- or undersize should be avoided to prevent stretching or compression of peripheral donor tissue.
9. As long as Bowman’s layer is intact a double running cross-stitch suture (according to Hoffmann) is preferred since it results in higher topographic regularity, earlier visual rehabilitation, and less suture loosening requiring only rarely suture replacement.
10. Intraoperative keratoscopy should be applied after removal of lid specula and fixation sutures.

     

Perioperative treatment and prognostic factors for penetrating keratoplasty in Acanthamoeba keratitis unresponsive to medical treatment

Background

The purpose of this research is to evaluate the prognostic factors for graft survival after penetrating keratoplasty (PK) for medically unresponsive Acanthamoeba keratitis.

Methods

In this retrospective, interventional case series, 22 affected eyes underwent therapeutic penetrating keratoplasty for medically unresponsive Acanthamoeba keratitis at Shandong Eye Institute during a 10-year period (1996-2006). Diagnosis of Acanthamoeba keratitis was made prior to surgery for 15 eyes, while a delayed diagnosis was made for the other seven eyes. Appropriate anti-microbial agents were administered based on the suspected etiological agents. Intravenous hydrocortisone was given only once in two patients. Systemic and topical use of steroids was avoided within 2 to 3 weeks after operation. The six patients who were misdiagnosed had intravenous hydrocortisone for 3 days postoperatively, and routine administration of systemic and topical steroids until Acanthamoeba was detected. Patients were followed up for 6 to 24 months (mean, 10 months) after PK.

Results

Of these patients, none wore contact lenses. The possible causes for infection included trauma with plant matter or dust (13 cases), poultry-feeding (six cases), and occupational exposure to oil (one case). Eighteen grafts were clear at the end of the follow-up. Six eyes (28%) had amoebic recurrence at 2 to 3 weeks after PK, of which five were misdiagnosed prior to surgery and received postoperative corticosteroids treatment. Four of the six eyes that developed a recurrence were regrafted, while the other two remained clear for the ensuing follow-up period.

Conclusions

PK may be performed in eyes with active Acanthamoeba keratitis. To improve the prognosis, surgeons should pay attention to antiamebal therapy and avoid prescribing corticosteroids in the early postoperative period.