Comparison of Clinical Outcomes of Same-size Grafting between Deep Anterior Lamellar Keratoplasty and Penetrating Keratoplasty for Keratoconus

Purpose

To compare the clinical outcomes between deep anterior lamellar keratoplasty (DALK) and penetrating keratoplasty (PKP) with same-size grafts in patients with keratoconus.

Methods

Medical records of 16 eyes from 15 patients treated from June 2005 through April 2011 were retrospectively reviewed. Patients with contact lens intolerance or who were poor candidates for contact lens fitting due to advanced cone underwent keratoplasty. The transplantations consisted of 11 DALK and 5 PKP with same-size grafting for keratoconus. Best-corrected visual acuity (BCVA), refractive error, corneal topographic profiling, and clinical course were compared between DALK and PKP groups.

Results

The follow-up period was 30 ± 17 months in the DALK group and 45 ± 20 months in the PKP group (p = 0.145). At final follow-up, the DALK and PKP groups achieved a BCVA (logarithm of the minimum angle of resolution) of 0.34 and 0.52, respectively (p = 0.980). Postoperative refractive error and mean simulated keratometric index showed myopic astigmatism in both groups without any statistical difference. Corneal irregularity index measured at 5 mm in the DALK group was less than that of the PKP group at 1-year follow-up (p = 0.021); however, at final follow-up, there was no longer a statistically significant difference. Endothelial cell counts were lower in the PKP group than in the DALK group at final follow-up (p = 0.021).

Conclusions

The optical outcomes of DALK with same-size grafts for keratoconus are comparable to those of PKP. Endothelial cell counts are more stable in DALK compared to PKP.     

Corneal collagen crosslinking for corneal ectasia of post-LASIK: one-year results

AIM: To evaluate the efficacy and safety of corneal collagen crosslinking (CXL) to prevent the progression of post-laser in situ keratomileusis (LASIK) corneal ectasia. METHODS: In a prospective, nonrandomized, single-centre study, CXL was performed in 20 eyes of 11 patients who had LASIK for myopic astigmatism and subsequently developed keratectasia.The procedure included instillation of 0.1% riboflavin-20% dextrane solution 30 minutes before UVA irradiation and every 5 minutes for an additional 30 minutes during irradiation. The eyes were evaluated preoperatively and at 1-, 3-, 6-, and 12-month intervals. The complete ophthalmologic examination comprised uncorrected visual acuity, best spectacle-corrected visual acuity, endothelial cell count, ultrasound pachymetry, corneal topography, and in vivo confocal microscopy. RESULTS: CXL appeared to stabilise or partially reverse the progression of post-LASIK corneal ectasia without apparent complication in our cohort. UCVA and BCVA improvements were statistically significant(P＜0.05) beyond 12 months after surgery (improvement of 0.07 and 0.13 logMAR at 1 year, respectively). Mean baseline flattest meridian keratometry and mean steepest meridian keratometry reduction (improvement of 2.00 and 1.50 diopters(D), respectively) were statistically significant (P＜0.05) at 12 months postoperatively. At 1 year after CXL, mean endothelial cell count did not deteriorate. Mean thinnest cornea pachymetry increased significantly. CONCLUSION: The results of the study showed a long-term stability of post-LASIK corneal ectasia after crosslinking without relevant side effects. It seems to be a safe and promising procedure to stop the progression of post-LASIK keratectasia, thereby avoiding or delaying keratoplasty.     

Femtosecond laser enabled keratoplasty for advanced keratoconus

Purpose:

To assess the efficacy and advantages of femtosecond laser enabled keratoplasty (FLEK) over conventional penetrating keratoplasty (PKP) in advanced keratoconus.

Materials and Methods:

Detailed review of literature of published randomized controlled trials of operative techniques in PKP and FLEK.

Results:

Fifteen studies were identified, analyzed, and compared with our outcome. FLEK was found to have better outcome in view of better and earlier stabilization uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), and better refractive outcomes with low astigmatism as compared with conventional PKP. Wound healing also was noticed to be earlier, enabling early suture removal in FLEK.

Conclusions:

Studies relating to FLEK have shown better results than conventional PKP, however further studies are needed to assess the safety and intraoperative complications of the procedure.     

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.     

Deep Anterior Lamellar Keratoplasty Using Irradiated Acellular Cornea with Amniotic Membrane Transplantation for Intractable Ocular Surface Diseases

Purpose

To report the clinical outcomes of deep anterior lamellar keratoplasty (DALK) when sterile gamma-irradiated acellular corneal tissues (VisionGraft) are used in combination with amniotic membrane transplantation (AMT) for intractable ocular surface diseases.

Methods

The medical records of fifteen patients who had DALK with AMT were retrospectively reviewed. Indications for surgery included ocular burn, bacterial keratitis, herpes simplex virus keratitis, corneal opacity with Stevens-Johnson syndrome, Mooren''s ulcer, idiopathic myxoid degeneration of corneal stroma, and recurrent band keratopathy. DALK was performed using partial-thickness acellular corneal tissue and a temporary amniotic membrane patch was added at the end of the operation.

Results

All cases that underwent DALK with AMT became epithelialized within 2 postoperative weeks. Twelve patients showed favorable outcomes without graft rejection, corneal opacification, or neovascularization. The other three grafts developed corneal opacification and neovascularization, and required additional penetrating keratoplasty (PK). Unlike the results of previous PKs, there were no graft rejections and the graft clarity was well-maintained in these three cases for at least 8 months after PK.

Conclusions

DALK using sterile acellular corneal tissues in combination with AMT may be a good therapeutic strategy for treating intractable ocular surface diseases because of lowered immune rejection, fibroblast activation, and facilitation of epithelialization. Furthermore, DALK can help stabilize the ocular surface, prolong graft survival, and may allow better outcomes when combined with subsequent PK.     

Corneal endothelium after deep anterior lamellar keratoplasty and penetrating keratoplasty for keratoconus: a four-year comparative study

Purpose:

To compare the status of corneal endothelium and central corneal thickness within the first four postoperative years after deep anterior lamellar keratoplasty (DALK) and penetrating keratoplasty (PK) in patients with keratoconus.

Materials and Methods:

Thirty-nine eyes (Group A) which had PK and 44 eyes (Group B) which had DALK for the treatment of keratoconus were included in this retrospective study. The endothelial cell density (ECD), the mean endothelial cell area and the coefficient of variation of cell area were assessed with a non-contact specular microscope, and the central corneal thickness (CCT) was measured with an ultrasound pachymeter.

Results:

Mean ECD loss rate at two years was 36.24% in Group A and 18.12% in Group B (P<0.001). Mean ECD loss rate at four years was 47.82% in Group A and 21.62% in Group B (P<0.001). Mean annual ECD loss rate was calculated 14.12% per year in Group A and 5.78% per year in Group B. In the PK group, increase in mean CCT was 15.60% in two years and 15.03% in four years, while in the DALK group, mean CCT increased by 8.05% in two years and 9.31% in four years.

Conclusions:

As the majority of ectatic disorders such as keratoconus occur in young people, long-term endothelial cell survival following treatment with keratoplasty is essential for the long-term visual ability. Our finding that corneal endothelial cell loss in the DALK group occurs at a slower rate than in the PK group suggests DALK as a safer alternative to PK in these selected patients.     

VisuMax飞秒激光辅助的穿透性角膜移植16例临床效果

目的 观察16例VisuMax飞秒激光辅助的穿透性角膜移植临床效果。方法 回顾性病例研究。16例（16眼）患者在南京军区南京总医院眼科行VisuMax飞秒激光辅助的穿透性角膜移植术。500 kHz飞秒激光进行供体及受体角膜的90°垂直边切。主要评价指标包括裸眼视力（UCVA）、最佳矫正视力（BCVA）、散光度、角膜厚度及内皮细胞计数等。随访时间为（9.6±5.6）个月。结果 所有手术顺利完成。UCVA从术前的光感～0.15提高到术后的手动～0.5,BCVA从术前的光感～0.3提高到术后的手动～0.8,平均散光度为（2.91±2.57）D,中央角膜厚度为（554.9±23.3）µm,角膜内皮细胞密度为（2 433±322）cells/mm2。结论 VisuMax飞秒激光辅助的穿透性角膜移植由于切口对合精确,术后视力恢复快,散光较小,视力较术前均有不同程度的提高。     

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.     

飞秒激光辅助的大气泡法深板层角膜移植治疗圆锥角膜

目的评价飞秒激光辅助的大气泡法深板层角膜移植术治疗圆锥角膜临床效果及安全性。方法系列病例研究。9例（11眼）圆锥角膜患者采用飞秒激光辅助进行大气泡法深板层角膜移植手术。供体及受体角膜均采用500 kHz VisuMax飞秒激光进行垂直边切,术前超声测量角膜最薄点厚度,角膜厚度为（359.7±49.8）μm,术前UCVA为指数～0.1,术前BCVA为指数～0.12,供体直径为（7.51±0.14）mm,受体直径为（7.38±0.10）mm,随访时间为（7.70±2.88）个月。结果所有患者手术顺利,术中无并发症,术后早期所有角膜植片透明。角膜厚度为（481.4±51.3）μm,角膜地形图恢复正常形态。术后最后1次随访,UCVA为0.15～0.40,BCVA为 0.30～0.80。结论飞秒激光辅助的大气泡法深板层角膜移植对于圆锥角膜患者具有良好的临床效果及安全性。     

Modified deep anterior lamellar keratoplasty for the treatment of advanced keratoconus with steep corneal curvature to help in eliminating the wrinkles in the Descemet's membrane

Aims:

To determine the clinical efficacy of modified deep anterior lamellar keratoplasty (DALK) for the treatment of advanced-stage keratoconus with steep curvature.

Materials and Methods:

In this interventional, non-comparative case series, 30 patients with advanced stages of keratoconus and curvature of more than 60 D underwent a modified DALK procedure. In this technique, after big-bubble formation, posterior stromal lamella was cut and removed 5 mm centrally (baring Descemet''s membrane completely) with posterior stromal layer remaining peripherally.

Results:

The study included 30 eyes (30 patients with a mean ± SD age of 25 ± 5.4 years). The follow-up examination was performed for all participants up to 12 months after the surgery. The mean uncorrected visual acuity (UCVA) increased from 20/800 before the surgery to a subsequent 3/10 (P =0.12). Likewise, best spectacle corrected visual acuity (BSCVA) improved, reaching 6/10 postoperatively (former quantity 20/200) (P =0.18). In addition, mean keratometry and keratometric astigmatism managed to achieve considerable improvement, from 58.8 ± 5.4 D to 46.5 ± 2.1 D and 7.8 ± 2.1 to 4.54 ± 1.54 D, respectively (P =0.52). Descemet''s membrane wrinkling was not seen in any patient postoperatively.

Conclusions:

This technique is effective in restoring acceptable vision and corneal regularity in advanced cases of keratoconus with a curvature more than 60 D who are also at risk of Descemet''s membrane wrinkling after DALK. Therefore, this procedure could prevent from Descemet membrane wrinkling in such cases.     

飞秒激光辅助的深板层角膜移植术治疗角膜基质病变

目的评价飞秒激光辅助的深板层角膜移植术（DALK）治疗角膜基质病变的早期临床效果及安全性。方法系列病例研究。13例（14眼）各种角膜基质病变患者（外伤后角膜瘢痕1眼,角膜炎后角膜瘢痕8眼,角膜基质层营养不良5眼）采用飞秒激光辅助的DALK术进行治疗。评价指标包括手术前后裸眼视力、最佳矫正视力、内皮细胞密度和并发症。结果所有手术均顺利完成,术中无任何并发症。平均随访时间（7．3±3．8）个月（2—14个月）。与术前相比,有11眼裸眼视力提高（78．6％）,平均提高1．7行（未变～6行）;所有患者最佳矫正视力均较术前提高,平均提高2．4行（1—8行）。有3眼采用治疗性准分子激光消融术进行辅助治疗,最后一次随访时统计,内皮细胞密度丢失率为1％,未见植片排斥、感染、上皮植入等并发症。结论飞秒激光辅助的DALK术可提高各种角膜基质病变患者的裸眼视力及最佳矫正视力,飞秒激光可透过混浊的角膜进行基质深层的有效光滑的切割。     

Sutureless femtosecond anterior lamellar keratoplasty: A 1-year follow-up study

Aim:

To study the safety and efficacy of sutureless femtosecond anterior lamellar keratoplasty (FALK) in patients with corneal stromal opacities.

Materials and Methods:

Eleven eyes of 11 consecutive patients with corneal stromal opacities involving < 250 μ due to various pathologies were included in the study. Preoperatively, all underwent anterior segment imaging with spectral domain optical coherence tomography (SD-OCT) (Bioptigen Inc., Durham, North Carolina, USA) to measure the depth of the stromal opacity. All patients underwent FALK, and bandage contact lens was placed for a period of 2 weeks. Postoperatively, uncorrected visual acuity, best corrected visual acuity (BCVA), and SD-OCT evaluation were performed.

Results:

All patients showed significant improvement in BCVA. The mean postoperative BCVA (in decimals) improved from 0.11 ± 0.06 preoperatively to 0.59 ± 0.08. There were no intraoperative or significant postoperative complications that were noticed.

Conclusion:

FALK is a safe and effective alternative to deep anterior lamellar keratoplasty or penetrating keratoplasty in the treatment of anterior stromal opacities.     

Changing trends in corneal graft surgery: a ten-year review

AIM: To review indications and corneal tissue use for penetrating and lamellar surgery between 2002 and 2011. METHODS: The surgical reports of corneal grafts performed during 2002-2011, using tissues supplied by the Eye Bank of Piedmont (Italy), were reviewed retrospectively. Patient demographic data, date of intervention, indication for surgery, and surgical technique used were recorded. Surgical techniques included penetrating keratoplasty (PK), deep anterior lamellar keratoplasty (DALK) and endothelial keratoplasty (EK). The χ2 test was used to compare the distribution of indications and types of surgical technique used, for corneal grafts done during 2002-2006 versus those done during 2007-2011. RESULTS: The number of corneal grafts increased by 30.7% from 2002-2006 to 2007-2011 (from 1567 to 2048). Comparing the two periods, both main indications and surgical techniques changed significantly. In 2007-2011, the proportion of interventions for aphakic/pseudophakic bullous keratopathy (from 16.8% to 21.3%), graft failure (from 16.4% to 19.1%) and Fuchs endothelial dystrophy (from 12.8% to 16.7%) all increased significantly (P<0.05), while those for keratoconus decreased significantly (from 35.6% to 27.3%; P<0.001). In 2007-2011, the proportion of PK decreased significantly (from 92.4% to 57.2%; P<0.001) while that of EK and DALK went from 0.4% to 30.2% (P<0.001) and from 7.2% to 12.6% (P<0.001) respectively. CONCLUSION: During 2002-2011 the number of interventions increased significantly for corneal endothelial diseases and graft failure. The growing demand for interventions for these diseases corresponded to the widespread adoption of EK techniques. The use of DALK also increased, but more moderately than EK procedures.     

Management of moderate and severe corneal astigmatism with AcrySof? toric intraocular lens implantation – Our experience

Purpose

Visual performance following toric intraocular lens implantation for cataract with moderate and severe astigmatism.

Setting

Cataract services, Shroff Eye Centre, New Delhi, India.

Design

Case series.

Method

This prospective study included 64 eyes of 40 patients with more than 1.50 dioptre (D) of pre-existing corneal astigmatism undergoing phacoemulsification with implantation of the AcrySof® toric IntraOcular Lens (IOL). The unaided visual acuity (UCVA), best corrected visual acuity (BCVA), residual refractive sphere and refractive cylinders were evaluated. Toric IOL axis and alignment error was measured by slit lamp method and Adobe Photoshop (version 7) method. Patient satisfaction was evaluated using a satisfaction questionnaire at 3 months.

Results

The mean residual refractive astigmatism was 0.57 D at the final follow-up of 3 months. Mean alignment error was 3.44 degrees (SD = 2.60) by slit lamp method and 3.88 degrees (SD = 2.86) by Photoshop method. Forty-six (71.9%) eyes showed misalignment of 5 degrees or less, and 60 (93.8%) eyes showed misalignment of 10 degrees or less. The mean log MAR UCVA at 1st post-op day was 0.172 (SD = 0.02), on 7th post-op day was 0.138 (SD = 0.11), and on 30th post-op day was 0.081 (SD = 0.11). The mean log MAR BCVA at three months was −0.04 (SD = 0.76).

Conclusion

We believe that implantation of AcrySof® toric IOL is an effective, safe and predictable method to correct high amounts of corneal astigmatism during cataract surgery.     

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.     

Limbal Stem Cell Allografts and Corneal Transplant in a Patient with Severe Corneal Melting and Perforation due to Thermokeratoplasty and Cross-Linking Treatment Burn

Purpose

To report corneal stem cell allografts in a patient with a persistent epithelial defect as well as corneal melting and perforation due to severe ultraviolet light burn and thermokeratoplasty treatment for keratoconus.

Methods

A 21-year-old female patient with corneal melting, perforation and a persistent epithelial defect in her left eye secondary to iatrogenic treatment for keratoconus, thermokeratoplasty and cross-linking was treated with penetrating keratoplasty, using a 9.0-mm diameter corneal graft and limbal stem cell allograft implants. At the end of the procedure, subtenonian injections of a combination of bevacizumab and triamcinolone were given.

Results

The patient had a favorable outcome 48 h after surgery, with an improvement of symptoms and a complete corneal healing. By the third week after surgery, she had a best-corrected visual acuity of 20/60 and a clear corneal graft, which remained stable for the 9 months of follow-up.

Conclusions

Treatment with limbal stem cell allografts and penetrating keratoplasty in a female patient with a large corneal defect and melting in her left eye was effective. Larger studies are warranted to explore the real impact of this procedure.Key words: Stem cells, Corneal melting, Thermokeratoplasty, Thermal burn     

Current treatment options for corneal ectasia

PURPOSE OF REVIEW: The approach to the management of various forms of corneal ectasia is changing, with the advent of new surgical and nonsurgical options. The purpose of this review is to summarize and evaluate relevant studies on new treatments for keratoconus, postrefractive surgery keratectasia, and peripheral ectatic corneal disorders. RECENT FINDINGS: Various alternatives to corneal transplantation for the management of keratoconus aim to enhance corneal rigidity by means of nonsurgical collagen cross-linking, or with the use of intrastromal corneal ring segments, and studies suggest that these treatments may reduce astigmatism or ectatic progression to varying degrees. Recent developments in anterior lamellar keratoplasty enable targeted replacement or augmentation of corneal stroma without replacement of endothelium, and include procedures such as deep anterior lamellar keratoplasty, microkeratome or laser-assisted anterior lamellar surgery, and peripheral tectonic lamellar keratoplasty procedures demonstrate successful reinforcement of peripheral stroma to reduce astigmatism. SUMMARY: These new forms of surgery are viable alternatives to conventional penetrating keratoplasty and bring added safety profiles for long-term visual rehabilitation and restoration of tectonic integrity in central and peripheral forms of corneal ectasia.     

Topographic Progression of Keratoconus in the Korean Population

Purpose

To develop a criterion for determining the topographic progression of keratoconus and to analyze the prognostic factors of progression.

Methods

Medical records of 211 eyes of 128 patients who had been followed up for more than 2 years on three or more occasions were retrospectively reviewed. Topographic parameters, including simulated K, corneal astigmatism, irregular astigmatism at 3 and 5 mm, thinnest-point pachymetry, anterior and posterior elevation, and inferior minus superior index, were used to determine topographic progression. Topographic progression was determined by the greatest kappa value associated with progression to corneal graft surgery. Eyes were separated into progressed and non-progressed groups on the basis of topographic progression. The association of clinical factors with topographic progression, including demographic factors, contact lens use, corneal erosion, and atopic history at the time of diagnosis, was assessed by logistic regression.

Results

When topographic progression was defined as five or more progressed topographic parameters, the greatest kappa value (0.354) was obtained. Ninety-four of the 211 keratoconic eyes (44.5%) were identified as topographically progressed. Age at diagnosis was significantly different between the progressed and non-progressed groups (22.2 vs. 24.7 years, p = 0.014). Logistic regression revealed that younger age at diagnosis was a risk factor for topographic progression (odds ratio, 0.948; 95% confidence interval, 0.907 to 0.991; p = 0.010).

Conclusions

We developed a criterion for evaluating topographic progression of keratoconus using diverse topographic indices. Younger age at diagnosis was associated with topographic progression of keratoconus.     

Pneumodescemetopexy with perfluoroethane (C2F6) for the treatment of acute hydrops secondary to keratoconus

Purpose

To evaluate the efficacy and safety of pneumodescemetopexy with intracameral perfluoroethane (C₂F₆) gas for the treatment of acute hydrops secondary to keratoconus.

Methods

Retrospective, non-comparative, interventional case series. Eight eyes of eight patients who presented with acute hydrops secondary to keratoconus between July 2009 and September 2013 were consecutively recruited. All were treated with intracameral 14% isoexpansile concentration of C₂F₆. Preoperative and postoperative best-corrected visual acuities (BCVA), intraoperative and postoperative complications, and time taken for resolution of corneal oedema were assessed.

Results

All the patients, except for one, were followed up for 1 year. The mean age of the cohort was 29.1±13.5 years. BCVA at presentation was 6/60 or less in all patients. Improvement of BCVA was achieved postoperatively in seven (87.5%) patients, with three (37.5%) patients achieving a BCVA of 6/18. The average time between initial presentation and complete resolution of corneal oedema was 60.0±32.1 days. The C₂F₆ gas persisted in the anterior chamber between 6 and 8 days. All the patients required only one injection during the treatment period. There was no intraoperative or postoperative complication noted during the follow-up period.

Conclusion

Pneumodescemetopexy with intracameral isoexpansile concentration of C₂F₆ gas serves as a safe and effective treatment modality for patients with acute hydrops secondary to keratoconus.     

Corneal biomechanical properties in eyes with no previous surgery, with previous penetrating keratoplasty and with deep anterior lamellar keratoplasty

Purpose

To compare the biomechanical properties of the cornea in eyes with no previous surgery, with keratoconus with previous penetrating keratoplasty (PK) and with keratoconus with previous deep anterior lamellar keratoplasty (DALK) using the Reichert Ocular Response Analyzer (ORA).

Methods

One hundred twenty eyes of 120 patients were included in this prospective comparative study. Forty eyes were with no previous ocular surgery (group 1), 40 eyes were with previous PK for keratoconus (group 2), and 40 eyes were with previous DALK for keratoconus (group 3). Corneal hysteresis (CH) and the corneal resistance factor (CRF) were measured with ORA.

Results

The CH and CRF values in group 2 were significantly lower than in group 1 and group 3 (p = 0.001). The CH and CRF values were similar in group 1 and group 3. There was no statistically significant difference between group 1 and 3.

Conclusion

Although the post-PK keratoconus cornea has weaker biomechanical properties, post-DALK keratoconus cornea is similar to normal cornea. A cornea weakened by keratoconus can be strengthened with lamellar keratoplasty.