Penetrating keratoplasty for keratoconus: visual outcome and success

Accelerated Corneal Crosslinking to Arrest Progression of Corneal Ectasia: A Prospective Multicenter Study

OBJECTIVES

To report the results of epithelium-off accelerated corneal collagen crosslinking (accelerated corneal crosslinking [ACXL]) in patients with progressive keratoconus.

METHODS

This prospective, nonrandomized, noncomparative, interventional, multicenter clinical study included all patients who underwent ACXL, either continuous (c-ACXL; 9 mW/cm 2 , 10', 5.4 J/cm 2 ) or pulsed (p-ACXL; 2″ON/1″OFF, 30 mW/cm 2 , 4.5', 5.4 J/cm 2 ) between January 2014 and May 2017. Best-corrected visual acuity, sphere, cylinder, spherical equivalent, and topographical keratometry data were collected preoperatively and at 1, 3, 6, 12, 18, and 24 months postoperatively.

RESULTS

Ninety-six eyes of 78 patients were included. The mean age was 20.8±4.4 years (14-33) for c-ACXL and 26.7±7.7 years (12-37) for p-ACXL. The mean best-corrected visual acuity was 0.4±0.4 for c-ACXL and 0.01±0.1 for p-ACXL preoperatively, and 0.3±0.3 ( P =0.0014) and -0.01±0.1 ( P =0.1554), respectively, at the last follow-up. The subjective sphere and spherical equivalent did not show statistically significant differences between the time points ( P >0.05). The subjective cylinder showed significant differences ( P =0.0013 for c-ACXL; P =0.0358 for p-ACXL). Keratometric values (K steep , K flat , and SimK) remained stable, with no statistically significant differences ( P >0.05). No major complications were noted.

CONCLUSIONS

Both c-ACXL and p-ACXL are equally safe and effective ACXL protocols in stabilizing the progression of keratoconus and can be considered alternatives to the conventional Dresden protocol.

Deep Anterior Lamellar Keratoplasty-Treated Keratoconic Eyes With Descemet Membrane Rupture

PURPOSE

The aim of this study was to evaluate the outcomes of deep anterior lamellar keratoplasty (DALK) and compare it with penetrating keratoplasty (PKP) in keratoconic eyes with Descemet membrane (DM) rupture.

METHODS

In this comparative retrospective case series, 33 keratoconic eyes with a history of hydrops underwent DALK and 27 received PKP. Baseline and postoperative visual acuity, corneal astigmatism, mean keratometry, endothelial cell density, and complication rates were measured.

RESULTS

The median follow-up of patients who underwent DALK was 45 months (range, 4-76 months) and that of patients who underwent PKP was 84 months (range, 4-136 months). Both procedures had comparable postoperative visual acuity, astigmatism, and mean keratometry. Significantly higher endothelial cell densities were observed in DALK than in PKP at 2, 3, and 5 years postsurgery (2043 ± 767 vs. 1165 ± 683 cell/mm2, P = 0.007, n = 12 in both groups at 2 years). Intra-DALK, 15 perforations occurred (44.12%) and 1 (2.94%) was converted to PKP. Graft rejection was diagnosed in 1 (3.03%) DALK procedure versus 8 (29.63%) PKP (P = 0.008), and other long-term complication rates were equivalent. Kaplan-Meier survival analysis also revealed a higher rejection-free survival rate for the DALK group (P = 0.012). Subgroup analysis within both groups based on the severity of preoperative DM rupture revealed no significant difference in any major 2-year outcomes.

CONCLUSIONS

DALK showed similar beneficial visual outcome and safety but significantly better endothelial protection over PKP in eyes with keratoconus and previous hydrops. Therefore, DALK is recommended in posthydrops cases irrespective of the DM rupture severity.

Outcomes of two different treatment modalities in mild to moderate keratoconus

PURPOSE

To describe visual and refractive outcomes of intrastromal corneal ring segments (ICRS) and toric implantable collamer lenses (TICL) implantation in cases of mild and moderate keratoconus.

METHODS

A prospective descriptive interventional case series. 40 eyes were allocated into two groups. First group (20 eyes) was treated with corneal collagen crosslinking (CXL) 1 month after ICRS implantation and the second group was treated using TICL after 1 year of CXL.

RESULTS

Both groups showed statistically significant improvement in spherical equivalent, cylindrical refraction, uncorrected visual acuity (UCVA) and best corrected visual acuity (BCVA) over the follow-up period.

CONCLUSION

Both ICRS and TICL are effective in treatment of mid and moderate keratoconus with more predictable visual results with TICL.

Recurrent Keratoconus: Corneal Transplants for Keratoconus Develop Tomographic Ectatic Changes

PURPOSE

The purpose of this study was to evaluate postoperative Scheimpflug imaging changes during the first 5 years after penetrating keratoplasty (PK) in patients with keratoconus (KC).

METHODS

This retrospective, interventional case series includes 31 eyes of 31 patients who underwent their first PK with a history of KC. Postoperative Scheimpflug imaging was performed 3 months after the removal of the last suture (baseline) and then repeated 3 and 5 years after the PK. Demographic data, donor and host trephination diameter, and Scheimpflug imaging (Pentacam HR, Oculus, Germany) parameters indicative of ectasia were analyzed to evaluate postoperative graft changes that occur after PK.

RESULTS

The maximal keratometry (Kmax) progressed significantly between baseline (53.5 ± 6.1 D) and postoperative year 3 and year 5 [56.5 ± 6.1 diopter (D) and 58.8 ± 7.9 D, P < 0.001]. Significant changes were also observed for the anterior best fit sphere and posterior best fit sphere ( P < 0.001 for 3 and 5 years compared with baseline). Kmax increased by at least 2 Ds for 74.2% of patients and up to 7 Ds or more for 25.8% of the patients. A significant inverse correlation was observed for host trephine size and progression of Kmax (r = -0.52, P = 0.01), which indicated that larger host trephination size was associated with a smaller increase in postoperative Kmax.

CONCLUSIONS

Tomographic graft changes indicative of ectasia were observed within 3 to 5 years after PK in patients with KC. These changes were observed more frequently and sooner after corneal transplants than previously reported.

Management of post-keratoplasty ametropia

Even after a successful corneal transplant, patients experience severe refractive errors, impeding their rehabilitation and satisfaction. Refractive errors can be caused by recipient pathology and corneal thickness, as well as intraoperative factors such as donor-host discrepancy, recipient's eccentric trephination, vitreous length, wound apposition, technique of suturing, and suture material. Also, wound healing and the interim between keratoplasty and suture removal contribute to astigmatism. Lamellar keratoplasty outperforms penetrating keratoplasty in terms of endothelial cell loss and endothelial graft rejection, yet the risk of developing refractive errors is comparable. Nonsurgical interventions such as spectacles and lenses fail to provide desirable vision in cases with high astigmatism and corneal irregularity. When these limitations are encountered, surgical interventions including incisional keratotomy, wedge resection, laser refractive surgeries, intracorneal segments, and intraocular lens implantation are employed. However, occasionally, none of these approaches deliver the desired effects, leading to the need for a repeat keratoplasty.

Penetrating Keratoplasty versus Deep Anterior Lamellar Keratoplasty for Keratoconus: A Systematic Review and Meta-analysis

Keratoconus is the most common form of primary corneal thinning. Different methods have been suggested to deal with the condition, including glasses, contact lenses, and surgical interventions, like penetrating keratoplasty (PKP) and deep anterior lamellar keratoplasty (DALK), well-known methods of the latter. This study was conducted to compare the outcomes and side effects of the two mentioned keratoplasty techniques. First, we systematically reviewed all original articles studies on PubMed, Scopus, Web of Science, and Embase. Then, the extracted data were pooled and meta-analyzed on each of the intended outcomes. A total of 30 studies were included in which PKP was more commonly performed compared to DALK. We found that adverse outcomes consisting of cataracts, graft rejection, graft failure, High-IOP, and corneal infection, were all more common findings in the PKP groups compared to the DALK groups. However, only for the high-IOP, cataracts, and graft rejection, the analysis of the extracted results demonstrated statistical significance. Overall, the DALK groups demonstrated significantly better results when considering the improvement levels by measuring the Endothelial Cell Count (ECC) and Spherical Equivalent (SE). In addition, though statistically insignificant, the Central Corneal Thickness(CCT), Best Corrected Visual Acuity(BCVA), Topographic Cylinder(TC), Refractive Cylinder values were greater in the PKP groups. Based on our study and with its limitations in mind, we can conclude that DALK can be a relatively safer and more effective procedure. Though, a larger number of high-standard randomized clinical trials still need to be conveyed for more definite conclusions.

Anterior pituitary, sex hormones, and keratoconus: Beyond traditional targets

"The Diseases of the Horny-coat of The Eye", known today as keratoconus, is a progressive, multifactorial, non-inflammatory ectatic corneal disorder that is characterized by steepening (bulging) and thinning of the cornea, irregular astigmatism, myopia, and scarring that can cause devastating vision loss. The significant socioeconomic impact of the disease is immeasurable, as patients with keratoconus can have difficulties securing certain jobs or even joining the military. Despite the introduction of corneal crosslinking and improvements in scleral contact lens designs, corneal transplants remain the main surgical intervention for treating keratoconus refractory to medical therapy and visual rehabilitation. To-date, the etiology and pathogenesis of keratoconus remains unclear. Research studies have increased exponentially over the years, highlighting the clinical significance and international interest in this disease. Hormonal imbalances have been linked to keratoconus, both clinically and experimentally, with both sexes affected. However, it is unclear how (molecular/cellular signaling) or when (age/disease stage(s)) those hormones affect the keratoconic cornea. Previous studies have categorized the human cornea as an extragonadal tissue, showing modulation of the gonadotropins, specifically luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Studies herein provide new data (both in vitro and in vivo) to further delineate the role of hormones/gonadotropins in the keratoconus pathobiology, and propose the existence of a new axis named the Hypothalamic-Pituitary-Adrenal-Corneal (HPAC) axis.

Combined Corneal Cross-Linking and Myoring Implantation in Advanced Keratoconus: Femtosecond Laser versus Manual Dissection

Background

Intrastromal corneal ring segments are widely adopted for keratoconus management. However, the complete ring (Myoring) was proposed to be superior in advanced cases. Myoring can be implanted either via femtoassisted or manual dissection techniques. A comparison between both techniques can delineate any differences in the outcomes.

Methods

This was a prospective interventional case series study. Sixty-four eyes with progressive advanced keratoconus were enrolled: 36 and 28 had femtoassisted or manual Myoring, respectively. Uncorrected visual acuity (UCVA), corrected distance visual acuity (CDVA), maximal keratometry (K _max), spherical equivalent (SE) and corneal thinnest location were measured in all eyes preoperatively and at one, six, and 12 months postoperatively. Epi-off corneal cross-linking (CXL) was performed eight weeks after Myoring implantation for all cases.

Results

Femtoassisted Myoring dissection significantly improved UCVA and CDVA from 0.1 ± 0.06 and 0.18 ± 0.1 preoperatively to 0.29 ± 0.08 and 0.43 ± 0.1 at 12 months. Also, manual technique similarly enhanced UCVA and CDVA from 0.11 ± 0.05 and 0.2 ± 0.1 preoperatively to 0.27 ± 0.2 and 0.4 ± 0.2 at 12 months. In terms of safety, while no cases of ring extrusion were encountered with the femtoassisted technique, six (21.4%) cases of extrusion were encountered in the manual group.

Conclusion

Femtoassisted or manual Myoring technique followed by CXL is an effective choice for advanced progressive keratoconus. Although it did not reach a statistical significance, the high extrusion rate with manual dissection is a red flag to be considered.

High power custom toric intraocular lens for correcting high corneal astigmatism in post-keratoplasty and keratoconus patients with cataract

Purpose:

To analyze the outcomes of phacoemulsification with high power customized toric intraocular lens implantation (IOL) in patients with high corneal astigmatism (6-10 D Cyl) post keratoplasty and keratoconus eyes with cataract.

Methods:

Five eyes post keratoplasty with clear graft, four eyes with stable keratoconus, one eye with pterygium excision scar with visually significant cataract were included in this retrospective study. Phacoemulsification was done followed by implantation of custom made high power toric IOL in all patients. Outcomes included uncorrected and best-corrected distance visual acuity (UDVA, BCVA), pre-operative astigmatism at the corneal plane and IOL plane, post-operative residual astigmatism, mean torus of all IOLs used were calculated.

Results:

The minimum follow-up time was 12 months. At the last follow-up visit, there was a significant improvement (pre-operative vs post-operative) of UDVA (1.5 ± 0.47 vs 0.28 ± 0.14 logMAR; P < 0.05), cylindrical refraction (-9.0 ± 1.80 D vs - 1.1 ± 0.45 vs ; P < 0.05). Range of IOL powers used was 1.0-26.50 DSph and 9.0-15.5 DCyl. Post-operative mean residual spherical equivalent was 0.75 ± 0.5.

Conclusion:

This novel study describes the effectiveness of custom toric IOLs in high astigmatism in the range of 9.0-15.5 DCyl. Phacoemulsification with implantation of a customized high power toric IOL was effective in correcting high astigmatism in complex cases in our study.

Long-term results of MyoRing implantation in patients with keratoconus

Clinical relevance: This study was conducted to evaluate five-year outcomes of MyoRing implantation in patients with keratoconus. The results showed that MyoRing implantation is a minimally invasive procedure and is safe and effective for improving visual acuity and refraction in most patients with keratoconus.Background: The long-term effects of MyoRing implantation on corneal features were studied.Methods: A total of 48 keratoconic eyes of 43 consecutive patients who had undergone MyoRing implantation using the Pocket Maker microkeratome (Dioptex, gmbh, Linz, Austria) and who had completed five years of follow‑ups were included in this retrospective study. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), refraction and keratometry (K) readings were measured and assessed pre-operation, and five years post-operatively. As well, post-operation satisfaction was assessed using a validated questionnaire.Results: Five years post-operatively, there was a significant improvement in UDVA, CDVA, K readings, spherical equivalent (SE), and manifest sphere and cylinder (p < 0.001). Mean UDVA was 1.20 logMAR before the surgery and 0.42 after the surgery (p < 0.001). Mean CDVA was 0.63 logMAR before the surgery and 0.20 logMAR after the surgery (p < 0.001). SE was improved from -6.53 dioptres (D) before the surgery to -2.23 D after the surgery (p < 0.001). Moreover, the results show that the mean K was reduced by 2.82 D after the surgery (p = 0.001). Overall, 81% of patients were moderately to highly satisfied five years after surgery.Conclusion: MyoRing implantation was found to be a minimally invasive procedure, and is safe and effective for improving visual acuity and refraction in most patients with keratoconus.

Toric Intraocular Lens Implantation in the Correction of Moderate-To-High Corneal Astigmatism in Cataract Patients: Clinical Efficacy and Safety

Methods

A total of 57 cataract patients (57 eyes) with regular corneal astigmatism (≥2.57 D) were enrolled in this retrospective cohort study. Phacoemulsification with toric IOL implantation was performed for all patients. The uncorrected visual acuity (UCVA) and best corrected visual acuity (BCVA) were recorded before and one year after surgery, and statistical analysis of preoperative corneal astigmatism, postoperative residual astigmatism, aberrations, IOL rotation, and related factors was performed to evaluate the efficacy, safety, and stability of toric IOLs in correcting moderate-to-high corneal astigmatism.

Results

One year after surgery, visual acuity was significantly improved compared with that before surgery (preoperative log MAR 0.87 ± 0.34 vs. postoperative log MAR 0.31 ± 0.26, p < 0.001), and the self-reported spectacle independence rate was 68.42%. The total residual astigmatism was 1.18 ± 0.85 D, which was significantly less than the preoperative value (3.41 ± 0.99 D) (p < 0.001). The degree of toric IOL rotation was 4.93 ± 3.02°, and 54.39% of patients had a lens rotation of less than 5°. The IOLs of 5.26% (3 eyes) of patients rotated more than 10°, and these patients received glasses instead of undergoing IOL repositioning.

Conclusions

Toric IOL implantation provided optimal vision outcomes and low spectacle dependence during a one-year follow-up period. The results from our study show that toric IOL implantation is a safe and effective option for cataract patients with moderate-to-high corneal astigmatism.

[Phacosurgery features in keratoconus]

The review summarizes the results of surgical treatment of cataracts in patients with keratoconus. The major challenges of phacosurgery in keratoconus are associated with intraocular lens (IOL) power calculation, choice of the most appropriate IOL model and additional interventions required to stabilize keratectasia and reduce corneal irregularity.

Penetrating Keratoplasty for Keratoconus in Vietnamese Patients

BACKGROUND

Keratoconus is an ectatic corneal disorder that can impair the visual acuity. Up to now, penetrating keratoplasty (PK) remains the most common surgical procedure to treat severe keratoconus. In Vietnam, most keratoconus patients come to visit doctor at severe stage and were treated by PK, so we conduct this study.

AIM

To evaluate the results of PK for keratoconus in Vietnamese patients.

METHODS

This was a retrospective study of 31 eyes with keratoconus who underwent PK in VNIO from January 2005 to December 2014.

RESULTS

The average visual acuity was 0.86 ± 0.37 logMAR (20/145). In the group of patients without amblyopia, best spectacle-corrected visual acuity of 20/60 or better was recorded in 75.9% of eyes and 93.1% of eyes achieved a best corrected visual acuity with hard contact lenses of 20/40 or better. Mean postoperative corneal power was 43.8 ± 4.5D. Mean corneal astigmatism was 5.9 ± 2.7D. 94.6% of grafts remained clear. Posterior subcapsular cataract developed in 22.6% of eyes. Graft rejection was recognized in 12.9% of eyes.

CONCLUSION

PK is an effective procedure with high rate of graft survival for keratoconus patients. However, patients should be aware of the necessary of optical correction to gain the best VA after surgery.

Mechanisms of Collagen Crosslinking in Diabetes and Keratoconus

Collagen crosslinking provides the mechanical strength required for physiological maintenance of the extracellular matrix in most tissues in the human body, including the cornea. Aging and diabetes mellitus (DM) are processes that are both associated with increased collagen crosslinking that leads to increased corneal rigidity. By contrast, keratoconus (KC) is a corneal thinning disease associated with decreased mechanical stiffness leading to ectasia of the central cornea. Studies have suggested that crosslinking mediated by reactive advanced glycation end products during DM may protect the cornea from KC development. Parallel to this hypothesis, riboflavin-mediated photoreactive corneal crosslinking has been proposed as a therapeutic option to halt the progression of corneal thinning by inducing intra- and intermolecular crosslink formation within the collagen fibrils of the stroma, leading to stabilization of the disease. Here, we review the pathobiology of DM and KC in the context of corneal structure, the epidemiology behind the inverse correlation of DM and KC development, and the chemical mechanisms of lysyl oxidase-mediated crosslinking, advanced glycation end product-mediated crosslinking, and photoreactive riboflavin-mediated corneal crosslinking. The goal of this review is to define the biological and chemical pathways important in physiological and pathological processes related to collagen crosslinking in DM and KC.

Graft survival rate of deep anterior lamellar keratoplasty for keratoconus: A meta-analysis

BACKGROUND

Deep anterior lamellar keratoplasty (DALK) is an optional treatment for patients with keratoconus, and the associated graft survival rate varies. Herein, we aimed to explore the graft survival rate of DALK in patients with keratoconus.

METHODS

PubMed, Web of Science, and ProQuest databases were searched to retrieve the related articles. General data, clinical characters, and graft survival rates were obtained directly from the included studies and analyzed by meta-analysis.

RESULTS

A total of 12 articles were included. The merged 1-, 3-, and 5-year graft survival rates were 100% (99.9-100%, P < .001), 92.9% (89.8-95.9%, P < .001), and 90.4% (86.0-0.948%, P < .001), respectively. Lower heterogeneity was shown in each subgroup that was divided neither according to the sample number nor number of surgeons.

CONCLUSION

The survival rate slightly decreases year by year, but the overall trend seems relatively stable. Ensuring that all DALK procedures are performed by a single surgeon might be helpful to improve the graft survival rate after surgery.

Corneal clarity measurements in patients with keratoconus undergoing either penetrating or deep anterior lamellar keratoplasty

Purpose

To compare the corneal clarity measurement between penetrating keratoplasty (PK) and deep anterior lamellar keratoplasty (DALK) in patients with keratoconus, using densitometry software for the Oculus Pentacam.

Methods

A retrospective comparative study was carried out at Manchester Royal Eye Hospital. Data were collected 12-18 months after corneal transplantation for keratoconus, including postoperative corneal densitometry, best corrected visual acuity (BCVA), central corneal thickness (CCT), and other relevant clinical details.

Results

Analysis of 37 keratoconus eyes from 36 patients found there was a significantly higher corneal densitometry measurement after DALK than PK. This was predominantly in the posterior layer of the concentric zone 0-2 mm of the cornea (P=0.0004). A significant correlation was found between postoperative BCVA and corneal densitometry in DALK groups at full thickness (P=0.03). This correlation was seen in the central 0-2 mm (P=0.03) and posterior 0-2 mm (P=0.04) zones. In addition, within the DALK group, a correlation was found between central corneal thickness and densitometry at full thickness 2-6 mm (P=0.007), central 0-2 (P=0.04), central 2-6 mm (P=0.01), and at posterior 2-6 mm (P=0.01) zones.

Conclusion

This study showed that corneal densitometry measurement differs depending on the type of corneal transplantation used to treat keratoconus patients. Densitometry may have an important role to play in the final BCVA achieved by patients undergoing corneal transplantation for keratoconus. Analysis of Oculus Pentacam images provides an objective evaluation to monitor the cornea status after the surgery.

Trends in Corneal Transplantation in Keratoconus

PURPOSE

To determine recent trends in and sociodemographic/comorbid conditions associated with penetrating keratoplasty (PK) and lamellar keratoplasty (LK) for keratoconus (KCN).

METHODS

Patients with KCN and subsequent PK and LK procedures were identified using International Classification of Diseases, 9th revision (ICD-9) and Current Procedural Terminology (CPT) billing codes. The change in surgical rates was calculated over a decade, and multivariate analysis demonstrated factors associated with undergoing surgery.

RESULTS

A total of 21,588 patients with KCN underwent 1306 PK procedures and 109 LK procedures during the study period. Individuals were significantly less likely to undergo PK from 2009 to 2012 compared with 2001 to 2008 [odds ratio (OR) 0.57, 95% confidence interval (CI) 0.47-0.68, P < 0.001]. Multivariate analysis revealed the factors that increased the likelihood of PK alone and included age 20 to 40 (OR 1.90, 95% CI, 1.19-3.04, P < 0.001), black race (OR 1.36, 95% CI, 1.06-1.74, P = 0.01), and education less than a bachelor's degree or only a high school diploma (OR 1.94-2.84, P < 0.001 for all comparisons). Female sex (OR 0.74, 95% CI, 0.63-0.88, P < 0.001) and household net worth either between 150 and 249k (OR 0.64, 95% CI, 0.48-0.84, P < 0.001) or more than $500,000 (OR 0.71, 95% CI, 0.51-0.99, P = 0.03) were traits associated with decreased odds of PK. No significant associations for LK were observed.

CONCLUSIONS

The rate of PK in KCN is decreasing in the United States. The third or fourth decade of life, male sex, black race, lower education, and greater household net worth are associated with increased odds of PK.

Stability of visual outcome between 2 and 5 years following corneal transplantation in the UK

Background and Aims

Many studies of corneal transplantation focus on graft failure or rejection as endpoints, or report visual outcomes at one postoperative time point. We aimed to study the stability of visual outcomes between 2 and 5 years following corneal transplantation.

Methods

All patients with keratoconus (868) or Fuchs endothelial dystrophy (FED) (569) receiving their first corneal transplant for visual purposes in the UK between January 2003 and December 2009 were included. The probability of visual improvement or deterioration (gain or loss of ≥2 Snellen lines, respectively) between 2 and 5 years after keratoplasty was modelled by multivariable logistic regression.

Results

The majority of keratoconus patients with a penetrating keratoplasty (PK) or deep anterior lamellar keratoplasty maintained their visual acuity (651/868; 75%) while 15% (133/868) improved and 10% (84/868) deteriorated. Similarly, most patients with FED who received a PK maintained their vision (395/569; 70%) while 18% (105/569) improved and 12% (68/569) deteriorated.

Penetrating Keratoplasty for Keratoconus With and Without Resolved Corneal Hydrops: Long-term Results

PURPOSE

To evaluate the long-term risk of endothelial rejection, graft survival, and associated factors following penetrating keratoplasty (PK) for keratoconus, with and without prior resolved corneal hydrops.

DESIGN

Retrospective cohort study.

METHODS

Primary outcome measures were endothelial rejection-free survival and failure-free survival. Secondary outcome measures were corneal neovascularization following hydrops and complications following PK.

RESULTS

A total of 245 eyes underwent PK for keratoconus with mean follow-up of 5.6 ± 3.6 years. Eyes with prior hydrops (n = 74) had lower endothelial rejection-free survival rates compared with eyes without prior hydrops: 86.5% ± 4.0% vs 86.5% ± 2.6% at 1 year, 61.0% ± 6.2% vs 76.9% ± 3.3% at 5 years, and 45.8% ± 10.1% vs 70.9% ± 4.3% at 10 years, respectively (P = .023). Multivariate analysis identified factors associated with endothelial rejection as age ≤25 years (P = .017), corneal neovascularization (P = .001), donor trephination size >8 mm (P = .017), and poor clinic attendance (P = .015). There was no difference in the failure-free survival rates with and without prior hydrops: 98.6% ± 1.3% vs 97.1% ± 1.3% at 1 year, 97.3% ± 1.9% vs 95.1% ± 1.9% at 5 years, and 97.3% ± 1.9% vs 92.2% ± 2.7% at 10 years, respectively (P = .42). Corneal neovascularization was present at the time of PK in 44.6% of eyes with prior hydrops and 7.6% without prior hydrops (P < .001).

CONCLUSIONS

Corneal neovascularization, a frequent complication of corneal hydrops, was associated with increased risk of endothelial rejection following PK. However, allograft survival was similar in eyes with and without prior hydrops.

[Corneal transplantation: study carried out at the Department of Ophthalmology, University Hospital Center Mohammed VI, Marrakech]

La kératoplastie transfixiante est l'une des plus fréquentes des greffes de tissus et transplantations d'organes. Le but de notre travail est de rapporter notre expérience en matière de greffe de cornée. C'est une étude prospective de 195 patients ayant bénéficié d'une greffe de cornée sur une période allant d'aout 2009 à Août 2015. Le recul moyen est de 21 mois. Les indications de la greffe étaient le kératocône 33.8%, les séquelles de traumatisme 10.7%, la kératopathie bulleuse 19.5%, les dystrophies héréditaires 10.7%, et les kératites herpétiques 9.2%. L'acuité visuelle initiale était inférieure à 1/10 dans 90% des cas. Nous avons observé une réaction de rejet dans 19 yeux dont 14 étaient récupérables, 33 hypertonies oculaires, 20cataracte, et 2 décollements descmetiques. La greffe de cornée apparaît comme une intervention donnant de bons résultats anatomiques et fonctionnels. Les résultats ne doivent pas occulter une surveillance post opératoire étroite et régulière pour dépister à temps d’éventuelles complications, en particulier le rejet de greffe.

Outcomes of femtosecond laser-assisted mushroom-configuration keratoplasty in advanced keratoconus

PURPOSE

To evaluate the long-term outcomes after femtosecond laser (FSL)-assisted mushroom-configuration keratoplasty in advanced keratoconus.

PATIENTS AND METHODS

Thirteen eyes with Amsler-Krumeich stage IV keratoconus underwent FSL-assisted mushroom-configuration penetrating keratoplasty (PKP) and deep anterior lamellar keratoplasty (DALK) at a tertiary referral centre. Preoperative risk factors included low orneal thickness, high keratometry measurements, previous hydrops, and central stromal scarring. Main outcome measures were visual acuity and refractive outcome.

RESULTS

The median follow-up was 33 months (range: 4-43). Preoperatively, the mean corrected distance visual acuity (CDVA) was 1.22±0.47 LogMAR (range: 0.5-1.9 LogMAR), mean minimum corneal thickness was 282±100.8 μm (range: 147-478 μm), and mean average keratometric (K) value was 63.4±7.63 dioptre (D; range: 57.0-75.7 D). Four patients underwent PKP and nine underwent DALK (two converted to PKP). Five patients subsequently underwent a modified arcuate mushroom interface dissection (AMID) procedure for astigmatic correction. At the final follow-up, the mean CDVA was 0.05±0.13 LogMAR (range: -0.10 to 0.20 LogMAR), mean spherical equivalent was -3.21±3.21D, mean cylindrical refractive error was 3.23±2.20 D, and mean average K was 43.1±1.53 D. Complications included early graft dehiscence, corneal vascularisation, stromal rejection, and sclerokeratitis. Sutures were completely removed at the mean 18.4 months for PKP and 9.1 months for DALK postoperatively.

CONCLUSION

FSL-assisted mushroom-configuration keratoplasty is feasible and safe in patients with stage IV keratoconus. AMID could further enhance the refractive outcome safely.

Cost effectiveness of collagen crosslinking for progressive keratoconus in the UK NHS

BACKGROUND

Keratoconus is a progressive degenerative corneal disorder of children and young adults that is traditionally managed by refractive error correction, with corneal transplantation reserved for the most severe cases. UVA collagen crosslinking is a novel procedure that aims to prevent disease progression, currently being considered for use in the UK NHS. We assess whether it might be a cost-effective alternative to standard management for patients with progressive keratoconus.

METHODS

We constructed a Markov model in which we estimated disease progression from prospective follow-up studies, derived costs derived from the NHS National Tariff, and calculated utilities from linear regression models of visual acuity in the better-seeing eye. We performed deterministic and probabilistic sensitivity analyses to assess the impact of possible variations in the model parameters.

RESULTS

Collagen crosslinking is cost effective compared with standard management at an incremental cost of £ 3174 per QALY in the base case. Deterministic sensitivity analysis shows that this could rise above £ 33,263 per QALY if the duration of treatment efficacy is limited to 5 years. Other model parameters are not decision significant. Collagen crosslinking is cost effective in 85% of simulations at a willingness-to-pay threshold of £ 30,000 per QALY.

CONCLUSION

UVA collagen crosslinking is very likely to be cost effective, compared with standard management, for the treatment of progressive keratoconus. However, further research to explore its efficacy beyond 5 years is desirable.

Treatment options for advanced keratoconus: A review

Traditionally, the mainstay of treatment for advanced keratoconus (KC) has been either penetrating or deep anterior lamellar keratoplasty (PK or DALK, respectively). The success of both operations, however, has been somewhat tempered by potential difficulties and complications, both intraoperatively and postoperatively. These include suture and wound-healing problems, progression of disease in the recipient rim, allograft reaction, and persistent irregular astigmatism. Taken together, these have been the inspiration for an ongoing search for less troublesome therapeutic alternatives. These include ultraviolet crosslinking and intracorneal ring segments, both of which were originally constrained in their indication exclusively to eyes with mild to moderate disease. More recently, Bowman layer transplantation has been introduced for reversing corneal ectasia in eyes with advanced KC, re-enabling comfortable contact lens wear and permitting PK and DALK to be postponed or avoided entirely. We offer a summary of the current and emerging treatment options for advanced KC, aiming to provide the corneal specialist useful information in selecting the optimal therapy for individual patients.

Long-term clinical outcomes of deep anterior lamellar keratoplasty in patients with keratoconus

PURPOSE

To report long-term clinical outcomes of deep anterior lamellar keratoplasty (DALK) in patients with keratoconus.

DESIGN

Retrospective noncomparative interventional study.

METHODS

setting: Single center. patients: Total of 158 eyes/150 consecutive patients with keratoconus with postoperative follow-up time equal to or greater than 4 years. intervention: DALK. main outcome measure(s): Uncorrected and corrected distance visual acuity (UDVA, CDVA), mean refractive spherical equivalent (MRSE), keratometry, endothelial cell density (ECD).

RESULTS

Mean postoperative follow-up was 76.9 ± 23.2 (range 48-120) months. Preoperative UDVA was 20/400 (1.5 ± 0.4 logMAR), CDVA 20/50 (0.7 ± 0.2 logMAR), MRSE -11.1 ± 5.6 diopters (D), mean keratometry 60.7 ± 6.1 D, topographic astigmatism 4.7 ± 2.6 D. At last postoperative follow-up visit, UDVA improved to 20/50 (0.5 ± 0.3 logMAR), CDVA to 20/25 (0.09 ± 0.1 logMAR), MRSE to -2.6 ± 3.5 D, mean keratometry to 44.4 ± 2.2 D, and topographic astigmatism to 2.9 ± 1.3 D. Postoperative ECD did not vary from preoperative values being 2070.5 ± 367.5 cell/mm(2) and 2198 ± 373 cell/mm(2), respectively, with 70% of eyes (111/158) showing ECD ≥2000 cells/mm(2). Eighteen eyes (11.3 %) developed stromal or epithelial rejection, 3 (1.8%) required regrafting. Eyes with successful big bubble showed greater CDVA than those that required manual dissection at follow-up equal to or less than 5 years but comparable results in the longer term.

CONCLUSIONS

DALK provides stable long-term visual and refractive outcomes. Risk of graft rejection, postoperative complication, and late ECD decay is reduced when compared to standard penetrating keratoplasty.

Efficacy and safety of deep anterior lamellar keratoplasty vs. penetrating keratoplasty for keratoconus: a meta-analysis

Purpose

To evaluate difference in therapeutic outcomes between deep anterior lamellar keratoplasty (DALK) and penetrating keratoplasty (PKP) for the clinical treatment of keratoconus.

Methods

A comprehensive search was conducted in Pubmed, EMBASE, Cochrane Library, and Web of science. Eligible studies should include at least one of the following factors: best corrected visual acuity (BCVA), postoperative spherical equivalent (SE), postoperative astigmatism and endothelial cell count (ECC), central corneal thickness (CCT), graft rejection and graft failure, of which BCVA, graft rejection and graft failure were used as the primary outcome measures, and postoperative SE, astigmatism, CCT and ECC as the secondary outcome measures. Given the lack of randomized clinical trials (RCTs), cohort studies and prospective studies were considered eligible.

Results

Sixteen clinical trials involving 6625 eyes were included in this review, including 1185 eyes in DALK group, and 5440 eyes in PKP group. The outcomes were analyzed using Cochrane Review Manager (RevMan) version 5.0 software. The postoperative BCVA in DALK group was significantly better than that in PKP group (OR = 0.48; 95%CI 0.39 to 0.60; p<0.001). There were fewer cases of graft rejection in DALK group than those in PKP group (OR = 0.28; 95%CI 0.15 to 0.50; p<0.001). Nevertheless the rate of graft failure was similar between DALK and PKP groups (OR = 1.05; 95%CI 0.81 to 1.36; p = 0.73). There were no significant differences in the secondary outcomes of SE (p = 0.70), astigmatism (p = 0.14) and CCT (p = 0.58) between DALK and PKP groups. And ECC in DALK group was significantly higher than PKP group (p<0.001). The postoperative complications, high intraocular pressure (high-IOP) and cataract were analyzed, fewer cases of complications occurred in DALK group than those in PKP group (high-IOP, OR 0.22, 95% CI 0.11–0.44, P<0.001) (cataract, OR 0.22; 95% CI 0.08–0.61, P = 0.004). And no cases of expulsive hemorrhage and endophthalmitis were reported.

Conclusion

The visual outcomes for DALK were not equivalent to PKP. The rate of graft failure was similar between DALK and PKP. Fewer postoperative complications occurred in DALK group, indicating that compared with PKP, DALK has lower efficacy but higher safety.

Evolving Techniques in Corneal Transplantation

Corneal transplantation is one of the most common types of human transplant surgery. By removing a scarred or damaged host cornea and replacing it with a clear and healthy donor transplant, this procedure helps to restore vision in a variety of corneal diseases. The traditional technique for corneal transplantation, penetrating keratoplasty (PKP), involves transplantation of all corneal layers. Over the past decade though, there has been a trend away from PKP as surgeons have developed partial thickness transplant procedures, such as deep anterior lamellar keratoplasty and Descemet stripping automated endothelial keratoplasty. These partial thickness transplant procedures selectively replace diseased host corneal tissue, while conserving healthy and functioning tissue. This review describes current surgical techniques in the field of corneal transplantation, with special emphasis on indications for transplantation and postoperative outcomes.

Prosthetic Replacement of the Ocular Surface Ecosystem (PROSE) scleral device compared to keratoplasty for the treatment of corneal ectasia

PURPOSE

To compare the ocular characteristics and visual outcomes of eyes with corneal ectasia that were fitted with the Prosthetic Replacement of the Ocular Surface Ecosystem (PROSE) scleral device to those that underwent keratoplasty.

DESIGN

Retrospective, comparative case series.

METHODS

We reviewed the charts of consecutive patients with corneal ectasia that were evaluated for PROSE or underwent keratoplasty at our institution. Clinical data, topographic indices, and corneal thickness were reviewed, and eyes were stratified according to the Amsler-Krumeich classification for severity of ectasia. Only the more severe eye of each patient was included in the study. We compared visual acuity before and after PROSE fitting or keratoplasty. For PROSE evaluations, achievement of satisfactory fit and continued wear at 1 year of follow-up were recorded.

RESULTS

From 2010 to 2012, 36 patients underwent PROSE evaluation for corneal ectasia while 37 patients underwent keratoplasty for the same indication. All eyes were successfully fitted with the PROSE device. Eyes in the keratoplasty group had more severe ectasia than eyes in the PROSE group (P = .038). Visual acuity was achieved more rapidly in the PROSE cohort compared to keratoplasty, and mean visual acuity was significantly better for all eyes (P < .0001) and when including only eyes with stage 4 ectasia (P < .001). More eyes with stage 4 ectasia achieved 20/25 visual acuity after PROSE than after keratoplasty (P = .003). At 1 year follow-up in the PROSE cohort, Snellen acuity was 20/28 (P = .108 vs keratoplasty), improving to 20/25 with over-refraction (P = .006 vs keratoplasty).

CONCLUSIONS

Eyes with advanced corneal ectasia can be successfully fitted with the PROSE device, and the visual acuity outcome for stage 4 ectasia was better and more rapid compared to keratoplasty. The acuity remained excellent with 1 year of follow-up. PROSE evaluation should be considered in patients with advanced corneal ectasia before proceeding to keratoplasty, especially if the ectasia is deemed stable.

Keratoconus: tissue engineering and biomaterials

Keratoconus (KC) is a bilateral, asymmetric, corneal disorder that is characterized by progressive thinning, steepening, and potential scarring. The prevalence of KC is stated to be 1 in 2000 persons worldwide; however, numbers vary depending on size of the study and regions. KC appears more often in South Asian, Eastern Mediterranean, and North African populations. The cause remains unknown, although a variety of factors have been considered. Genetics, cellular, and mechanical changes have all been reported; however, most of these studies have proven inconclusive. Clearly, the major problem here, like with any other ocular disease, is quality of life and the threat of vision loss. While most KC cases progress until the third or fourth decade, it varies between individuals. Patients may experience periods of several months with significant changes followed by months or years of no change, followed by another period of rapid changes. Despite the major advancements, it is still uncertain how to treat KC at early stages and prevent vision impairment. There are currently limited tissue engineering techniques and/or "smart" biomaterials that can help arrest the progression of KC. This review will focus on current treatments and how biomaterials may hold promise for the future.

Lamellar keratoplasty following thermokeratoplasty in the treatment of acute corneal hydrops

PURPOSE

To observe the efficacy of deep anterior lamellar keratoplasty (DALK) for treatment of acute hydrops in keratoconus after anterior chamber paracentesis combined with thermokeratoplasty.

DESIGN

Retrospective, noncomparative clinical case series.

METHODS

Twenty-one patients (21 eyes) suffering acute hydrops associated with keratoconus were treated first by anterior chamber paracentesis combined with thermokeratoplasty. At 1 week after the edema was absorbed, and Descemet membrane ruptures and stromal clefts were cured, all patients received modified DALK. Descemet membrane re-ruptures during surgery were recorded, if any. Graft transparency, visual acuity, recipient folds or opacity, and immune rejection were monitored for 6 months to 1 year.

RESULTS

All the corneal edema alleviated rapidly, and the intrastromal clefts narrowed within 1 week after combined anterior chamber paracentesis and thermokeratoplasty. DALK was performed successfully in all patients within 2 weeks after the first surgical procedure, with no Descemet membrane rebreaking or corneal perforation. The recipients were completely clear in 7 eyes, and mild fusiform scars appeared at the central recipient in 14 eyes. All the opacity of Descemet membrane ruptures became slight or even disappeared after 6 months. The mean best-corrected visual acuity was improved to 20/30 at 1 year after DALK. No immune rejection occurred.

CONCLUSIONS

Anterior chamber paracentesis combined with thermokeratoplasty can accelerate the absorption of corneal edema in patients with acute corneal hydrops (within 1 week) and Descemet membrane rupture healing without obvious opacity (within 2 weeks). During this window phase, DALK could be performed safely, and good visual acuity may be obtained.

Long-term outcomes of penetrating keratoplasty in keratoconus: analysis of the factors associated with final visual acuities

AIM

To investigate the long-term results of penetrating keratoplasty (PK) in patients with keratoconus (KC) and to evaluate factors that might influence the final visual outcome.

METHODS

We retrospectively reviewed the data of all patients with clinical KC who had undergone PK by a single corneal surgeon in a single center from May 1980 to December 2005. The age of the patients, preoperative best-corrected visual acuity (BCVA), corneal thickness, death to preservation time, and preservation to transplantation time were recorded. Additionally, postoperative complications such as graft rejection, development of glaucoma and specular microscopy were checked during the follow-up.

RESULTS

Sixty-nine eyes from 69 patients were finally included. The follow-up period was 8.64±6.13y. Graft rejection occurred in 4 eyes of 69 cases (5.8%), and the time to graft rejection was 2.1±1.3y. A Kaplan-Meier survival analysis showed that the estimated cumulative probability of graft rejection at 6, 13, and 17y after PK were 95.6%, 90.0%, and 78.8%, respectively. When we evaluated factors that might influence final BCVA in eyes, no disparity donor-host trephine size (same graft size) as well as higher spherical equivalent, and average K-value were associated with higher final BCVA. (P=0.006, 0.051, 0.092, and 0.021 in eyes with follow-up <8y; P=0.068, 0.065, and 0.030 in eyes with follow-up ≥8y, respectively).

CONCLUSION

The long-term results of PK in patients with KC were favorable with a high percentage of good BCVA. Less myopic change and low average K-reading, as well as a surgical technique using the same size donor-recipient button may provide better visual outcomes particularly in patients with KC.

Corneal lymphangiogenesis in herpetic stromal keratitis

Corneal lymphangiogenesis is the extension of lymphatic vessels into the normally alymphatic cornea, a process that compromises the cornea's immune-privileged state and facilitates herpetic stromal keratitis (HSK). HSK results most commonly from infection by herpes simplex virus-1 (HSV-1) and is characterized by immune- and inflammation-mediated damage to the deep layers of the cornea. Current research demonstrates the potential of anti-lymphangiogenic therapy to decrease and prevent herpes-induced lymphangiogenesis.

Applications of different types of gas-permeable contact lenses in keratoconus and their visual results

PURPOSE

To show applications of different types of gas-permeable contact lenses in patients with keratoconus and to compare visual acuity (VA) results.

METHODS

A total of 229 eyes of 133 patients who used different types of rigid gas-permeable contact lenses between April 2003 and April 2010 at the Cornea and Contact Lens Unit of Eye Clinic 2 of the Ministry of Health, Ulucanlar Eye Training and Research Hospital, were included. Visual acuity of patients was classified as uncorrected and corrected with eyeglasses and corrected with contact lenses. The patients were compared in terms of VA, daily contact lens wear time, and complications.

RESULTS

A total of 70 out of 133 (52.6%) patients in our study were male, and 63 (47.4%) were female. The mean age was 25.9 ± 7.03 years (12-45). As for the classification of the 229 eyes included in the study, 136 of 229 (59.4%) eyes had moderate keratoconus, 88 (38.4%) had advanced keratoconus, and 5 (2.2%) had severe keratoconus. Following the contact lens application, the VA in all patients increased when compared to uncorrected and corrected with eyeglasses groups and the difference was statistically significant (p<0.005). When a comparison of different types of contact lenses was made, a statistically significant difference was not found (p>0.5) in terms of increase in VA. When patients were evaluated in terms of contact lens wear times, it was observed that Boston Equalens II was preferred by patients wearing lenses 4-8 hours/day. For patients wearing lenses more than 8 hours a day, Rose K lens was used the most. No serious complication was observed in any of the patients that would lead them to stop wearing contact lenses during the follow-up period. There was also no need for keratoplasty in any patient during the follow-up period.

CONCLUSIONS

We detected an increase in VA in patients with rigid contact lenses. In addition, some contact lenses were better tolerated by patients and were used for a longer time during the day.

Cataract surgery with toric intraocular lens for correction of high corneal astigmatism

OBJECTIVE

To analyze the outcomes of cataract surgery with high-power toric intraocular lens (IOL) implantation in patients with high corneal astigmatism.

DESIGN

Retrospective case series.

PARTICIPANTS

Twelve eyes of 9 patients.

METHODS

Patients with idiopathic, pathologic, or postsurgical corneal astigmatism and a visually significant cataract were included in the study. Cataract extraction with implantation of a custom-made high-power toric IOL was performed on all patients. Outcomes included uncorrected and best corrected distance visual acuity (UDVA and BCDVA), manifest refraction, and mean and steepest keratometry. Analysis of astigmatic vectors was also performed.

RESULTS

The mean follow-up time was 3.75 months. At the last follow-up visit, there was a significant improvement of UDVA (1 ± 0.64 vs 0.39 ± 0.21 logMAR; p < 0.05), cylindrical refraction (-4.72 ± 1.13 vs -1.81 ± 1.10 D; p < 0.01), and refractive spherical equivalent (-4.56 ± 5.58 vs -0.36 ± 1.19 D; p < 0.05). The BCDVA improvement did not reach statistical significance. Astigmatism on the target axis was reduced by an average of 5 D (p < 0.01).

CONCLUSIONS

Cataract surgery with implantation of a high-power toric IOL was safe and effective in correcting high values of corneal astigmatism.

Clinical outcome of repeat penetrating keratoplasty

PURPOSE

To compare the clinical outcome of regrafts with first grafts.

METHODS

Two-year outcome data were obtained from the Swedish Cornea Transplant Register for patients undergoing penetrating keratoplasty between 2001 and 2008. Only data from the 3 centers with follow-up return rates >75% were included. The survival and visual outcome of regrafts with the original diagnoses of keratoconus, Fuchs endothelial dystrophy (FED), or bullous keratopathy (BK) were compared with first grafts for the same diagnoses by univariate and logistic regression methods.

RESULTS

For keratoconus, the failure rate increased 3-fold in regrafts compared with first grafts (ie, 17% vs. 6%; P = 0.002) and doubled in FED regrafts (33% vs. 15%; P = 0.001). In BK, the failure rate was already high in first grafts, and the increase in failure of regrafts was minimal (P = 0.9). Visual acuity was also worse in regrafts compared with first grafts, mainly in the keratoconus and FED patients. In the keratoconus group, visual acuity with preferred correction was ≥0.5 in 69% of first grafts compared with only 55% in regrafts (P = 001). In FED, 52% of first grafts but only 19% of regrafts achieved visual acuity ≥ 0.5 (P = 0.001). The visual outcome of regrafts in BK was poor but little different from first grafts where fewer than 20% achieved visual acuity ≥ 0.5.

CONCLUSIONS

This analysis confirmed the poorer survival of regrafts where the original indication was keratoconus or FED. In addition, visual outcome was also worse than in the first grafts. However, the outcomes of regrafts in BK were similar to first grafts.

Long-term comparison of full-bed deep anterior lamellar keratoplasty and penetrating keratoplasty in treating keratoconus

OBJECTIVE

To compare postoperative outcomes of full-bed deep anterior lamellar keratoplasty (DALK) with penetrating keratoplasty (PK) in treating keratoconus.

METHODS

Seventy-five eyes of 64 patients who received full-bed DALK and 52 eyes of 51 patients who received PK between June 2000 and August 2010 were included in this retrospective study. Full-bed DALK was performed using Yao's hooking-detaching technique. PK was performed using a standard technique. Intraoperative and postoperative complications, visual acuity, rejection, graft survival, endothelial cell density, corneal sensation recovery, and re-innervation were compared between the two groups.

RESULTS

A best correct visual acuity of 0.5 or better was achieved in 90.7% of eyes after full-bed DALK and in 92.3% of eyes after PK (P=0.75). By the fifth postoperative year, graft endothelial cell loss reached 34.6% in the PK group vs. 13.9% in the full-bed DALK group (P<0.001). There were no statistical differences in corneal sensitivity recovery or corneal re-innervation between the groups (P>0.05). Intraoperative microperforation occurred in seven out of 75 (9.3%) eyes with a temporally postoperative double anterior chamber in two eyes in the full-bed DALK group. Postoperative complications in the PK vs. the full-bed DALK groups respectively were: rejection (7.7% vs. 0%, P=0.015), high intraocular pressure (IOP) (46.2% vs. 1.3%, P<0.001), secondary glaucoma (9.6% vs. 0%, P=0.006), complicated cataract (19.2% vs. 0%, P<0.001), and wound dehiscence (9.6% vs. 0%, P=0.006).

CONCLUSIONS

Both full-bed DALK and PK can offer long-term satisfactory visual outcomes for keratoconus. Graft rejection, secondary glaucoma, complicated cataracts, and constant endothelial cell loss were observed in eyes only after PK.

Implantable Collamer Lens for Correction of Refractive Errors in Patients with Keratoconus following Collagen Cross-Linking: One Year Follow-up

Objective

The purpose of this study is to assess the predictability, safety, efficacy and stability of correction of refractive errors in patients with keratoconus using Visian implantable collamer lens (ICL) following collagen cross-linking.

Materials and methods

This prospective, non-comparative study evaluated 20 eyes of 14 patients with keratoconus subjected to implantation of intraocular collamer lens at least 1 year following collagen cross-linking and stable refraction. Mean preoperative myopia was −8.43 ± 5.13 Diopters (D) (–3.5 to −20.0D and mean cylinder was −2.19 ± 1.28D (0.0 to −4.5D). The preoperative spherical equivalent (SE) was −9.52 ± 5.33D (–3.75 to −21.25D). During the 12 months follow-up, uncorrected visual acuity, best corrected visual acuity, refraction, intraocular pressure and vaulting are measured.

Results

At 12 months postoperatively, 90% of eye had refractive cylinder of <1.0D with (p = 0.003) and 20 (100%) eyes was within ±0.75D of sphere at 1 year (r2 = 0.99) and (p = 0.0085). The mean postoperative BCVA in decimal was 0.498 ± 0.232, while the mean preoperative BCVA was 0.484 ± 0.285. The safety index at 12 months was 1.02. The mean postoperative UCVA in decimal was 0.498 ± 0.232 and the mean preoperative BCVA is 0.484 ± 0.29 and the efficacy index at 12 months was 1.01.

Conclusion

Implantation of Visian Intraocular collamer lens is predictable, safe and effective way to correct refractive error in patients with keratoconus following collagen cross-linking.

How to cite this article

Shuber HS. Implantable Collamer Lens for Correction of Refractive Errors in Patients with Keratoconus following Collagen Cross-Linking: One Year Follow-up. Int J Kerat Ect Cor Dis 2014;3(1):29-35.

Deep anterior lamellar keratoplasty for the treatment of stromal corneal dystrophies

PURPOSE

To report the perioperative complications and clinical outcomes after deep anterior lamellar keratoplasty (DALK) using the big bubble technique in eyes with stromal corneal dystrophies.

PATIENTS AND METHODS

Seventy-four eyes of 65 patients who underwent DALK for stromal corneal dystrophies were evaluated in this retrospective interventional case series study. Main outcome measures were intraoperative and postoperative complications, postoperative uncorrected visual acuity, best spectacle-corrected visual acuity, spherical equivalent refraction, and topographic astigmatism.

RESULTS

There were 44 eyes with macular corneal dystrophy, 18 eyes with lattice dystrophy, and 12 eyes with granular dystrophy. DALK was completed in 69 cases (94.6%). Descemet membrane microperforations occurred in 6 eyes (8.7%). The mean follow-up period was 43.5 ± 23.9 months, ranging from 12 to 96 months. Postoperative best spectacle-corrected visual acuity of 0.5 or better was present in 52 of 69 eyes (75.4%). There were 3 episodes of stromal graft rejection, which responded to topical therapy. Lattice dystrophy recurred in 6 eyes (35.3%).

CONCLUSION

DALK using the big bubble technique is an effective procedure in the treatment of patients with corneal stromal dystrophies. Recurrence of lattice dystrophy was relatively high.

Penetrating keratoplasty for keratoconus: visual and graft survival outcomes

OBJECTIVES

To evaluate the complications, and visual and graft survival outcomes in eyes that had undergone penetrating keratoplasty (PKP) for keratoconus.

METHODOLOGY

This restrospective study includes 311 patients with keratoconus who had undergone PKP between January 1, 2001, and December 31, 2002, at King Khaled Eye Specialist Hospital. All patients were followed up postoperatively (maximum follow-up, 65.77 months).

RESULTS

The mean age of patients with keratoconus at transplantation was 23.72 years. A preoperative best spectacle-corrected visual acuity (BSCVA) OF 20/40 or better was achieved in 13 eyes (4.2%). At a mean follow-up of 27 months, 212 eyes (68.2%) achieved a BSCVA of 20/40 or better. Postoperative visual acuity was significantly associated with preoperative visual acuity (P < 0.00). Only 6 eyes (1.9%) experienced graft failure, with a mean follow-up of 23.62 months. The graft rejection rate (6.8%) was a significant risk factor for failure (P = 0.00). Age, gender, corneal graft diameter, and intraoperative vitreous loss had no statistically significant effects on the PKP outcome (P> 0.05). Kaplan-Meier analysis revealed that the probabilities of graft survival were 99.8% at 1 year and 97.6% at 5 years after transplantation.

CONCLUSION

Performing PKP in eyes with keratoconus is associated with good visual results and an excellent graft outcome.

Long-term outcomes in patients who received a corneal graft for keratoconus between 1980 and 1986

PURPOSE

To estimate the probability of allograft rejection, graft failure, and recurrent keratoconus (KC) and to assess vision-specific quality of life 20 to 25 years after corneal transplantation for KC.

DESIGN

Retrospective case series.

METHODS

Two hundred nineteen eyes of 184 subjects were identified from the Michigan Corneal Transplantation Patient Registry as receiving corneal transplantation for KC from 1980 through 1986. Current ophthalmic examinations and the 25-item National Eye Institute Visual Function Questionnaire were obtained. Kaplan-Meier analyses were used to estimate the time-related probability of allograft rejection, graft failure, and KC recurrence. Cox regression was used to identify predictive factors of these outcomes. The 25-item National Eye Institute Visual Function Questionnaire scores were summarized with descriptive statistics.

RESULTS

Follow-up was available up to 27 years after surgery (median, 10 years). Rejection occurred in 98 of 219 grafts. Most rejections occurred in the first 2 years (probability, 41%; standard error, 3%). KC recurrence was noted in 6 grafts 9 to 20 years after surgery, with a 20-year probability of 10% (standard error, 4%). Eighteen grafts failed, with a 20-year probability of 12% (standard error, 3%). Larger host trephine size, male donor gender, and nonwhite donor race were associated with increased rejection hazard. Worse astigmatism and nonwhite recipient race were associated with increased failure hazard. Twenty-eight subjects completed the 25-item National Eye Institute Visual Function Questionnaire at an average of 23 years after surgery (range, 18 to 26 years). Their mean composite score was 84.5 (standard deviation, 12.1).

CONCLUSIONS

Allograft rejection is frequent in the 2 years after corneal graft for KC. However, the 20-year probabilities of graft failure and recurrent KC are low. Given the relative youth of KC graft recipients, these statistics should enhance the information they receive.

Correction of postkeratoplasty ametropia in keratoconus patients using a toric implantable Collamer lens

PURPOSE

To evaluate the efficacy and safety of a toric implantable Collamer lens (Visian TICL®) for correction of high postkeratoplasty ametropia in patients with keratoconus. 


METHODS

Seven eyes of 7 keratoconus patients postkeratoplasty (5 M, 2 F; mean age 34.1±5.9 years, range 28-44) unable to wear glasses or contact lenses were included in the study. A foldable phakic posterior chamber Collamer toric lens was injected through a standard 3.0-mm clear corneal temporal incision. Uncorrected distance visual acuity (UCDVA, logMAR), best-corrected distance visual acuity (BCDVA, logMAR), spherical refraction, cylindrical refraction, and refractive spherical equivalent (RSE) were measured preoperatively and postoperatively. Postoperative adverse events were recorded. 


RESULTS

. The mean follow-up was 12.8±8.8 months (range 4-30). A significant (p<0.01) improvement was observed postoperatively in mean UCDVA (1.18±0.4 vs 0.2±0.1), spherical refraction (-5.89±3.43 vs 0.53±0.75), cylindrical refraction (-4.39±0.75 vs -1.74±0.84), and RSE (-8.09±3.77 vs -0.33±0.54). The BCDVA changes were not significant (0.09±0.11 vs 0.05±0.08). All patients gained ≥5 lines of UCDVA (average 7.6±1.9 lines). The number of patients with UCDVA ≥6/12 (0.3 logMAR) increased after surgery (0% vs 87.5%; p<0.01), while the number of patients with BCDVA ≥6/12 was unchanged (100% vs 100%; NS), with 0% (0/7) of patients losing ≥2 BCDVA lines. No complications were observed postoperatively. 


CONCLUSIONS

Toric implantable Collamer lens was safe and effective in correcting postkeratoplasty myopia and astigmatism in keratoconus patients.

Optical pachymetry-guided custom excimer laser-assisted lamellar keratoplasty for the surgical treatment of keratoconus

PURPOSE

To evaluate the anatomic and functional results of optical pachymetry-guided custom excimer laser-assisted lamellar keratoplasty in keratoconus patients.

SETTING

Eye Clinic, University of L'Aquila, L'Aquila, Italy.

DESIGN

Prospective noncomparative case series.

METHODS

Patients with keratoconus having unilateral surgery using custom excimer laser-assisted lamellar keratoplasty were evaluated. A transepithelial excimer laser ablation was planned to leave an estimated uniform thickness residual stromal corneal bed of 200 μm. The donor lamella was prepared with the excimer laser and subsequently sutured to the host cornea using 16 single 10-0 nylon sutures. The eyes were examined preoperatively and 3, 6, 12, and 24 months postoperatively. Outcome measures were uncorrected (UDVA) and corrected (CDVA) distance visual acuities, manifest refraction, computerized videokeratography, pachymetry, and endothelial specular microscopy.

RESULTS

Of the forty-three treated eyes, 35 were available at the 24-month follow-up visit, at which time the UDVA was better than 20/60 in 16 patients (45.7%) and the CDVA was 20/40 or better in 31 patients (88.6%). The mean refractive astigmatism was -2.11 diopters (D) (P<.05) and the mean spherical equivalent manifest refraction, -2.60 D (P<.05). No statistically significant changes in mean corneal endothelial cell density were observed postoperatively. In 1 case, the donor lamella was exchanged secondary to an altered reepithelialization process with initial corneal melting.

CONCLUSION

Two-year findings indicate that pachymetry-guided custom excimer laser-assisted lamellar keratoplasty is a useful surgical treatment for moderate to advanced keratoconus, preventing the need for the more invasive procedure of penetrating keratoplasty.

Outcomes of deep anterior lamellar keratoplasty for keratoconus: learning curve and advantages of the big bubble technique

PURPOSE

To evaluate retrospectively the outcomes of a case series of deep anterior lamellar keratoplasties by air dissection (DALK-AD) using the big bubble (BB) technique, in the surgical treatment of keratoconus (KC).

METHODS

Forty-four consecutive keratoplasties of 42 patients for KC were performed at the French National Reference Center for KC from January 2008 to June 2010 by the same surgeon with the aim of systematically performing DALK-AD with the BB technique. The outcomes of the DALK-AD not converted to penetrating keratoplasty were analyzed, and a learning curve was established to successfully achieve the DALK-AD using the BB technique.

RESULTS

Thirty-two DALK-AD procedures were successfully performed among 44 consecutively operated keratoplasties, with 12 being converted to penetrating keratoplasty during the surgical procedure. At 12 months, the mean best-corrected logarithm of the minimum angle of resolution visual acuity was 0.88 ± 0.14 with 93.3% seeing best-corrected visual acuity ≥ 20/30 and 100% seeing best-corrected visual acuity ≥ 20/40. The mean gain of visual acuity in logarithm of the minimum angle of resolution lines at 6 and 12 months was 6.12 ± 3.97 (P < 0.0001) and 6.94 ± 4.18 (P < 0.005), respectively. The rate for intraoperative and postoperative complications was 31.8% and 4.5%, respectively.

CONCLUSION

Despite a learning period needed to successfully perform deep lamellar anterior keratoplasty with the BB technique, this approach is safe and provides very good visual outcomes when adequate baring of Descemet membrane is achieved. The learning curve showed that complications related to this technique decrease significantly after the first 10 cases.

Long-term graft survival in deep anterior lamellar keratoplasty

PURPOSE

To determine corneal graft survival rates up to 10 years in a large consecutive series of deep anterior lamellar keratoplasties (DALKs).

METHODS

A retrospective, consecutive, noncomparative cases series of DALK procedures in a total of 806 eyes of 711 patients with stromal diseases and healthy endothelium performed between 2000 and 2009. Inclusion criterion was surgery performed by a single surgeon (660 eyes), with at least 6 months of follow-up. Graft survival was analyzed using the Kaplan-Meier method. Endothelial loss was analyzed with the Gaussian distribution and the χ methods. Follow-up time, and preoperative and postoperative endothelial cell density (ECD) were considered in the analyses.

RESULTS

Six hundred sixty eyes of 502 patients met the entry criteria. Mean length of follow-up was 4.5 years (range, 0.5-10 years). We report an average graft survival rate of 99.3% (range, 98.5%-100%); 3 eyes (0.45%) experienced graft failure and 1 eye (0.15%) developed late endothelial failure because of an intraoperative complication. Predominant indications for DALK in this series were keratoconus (74%), postherpetic keratitis scarring (15%), and corneal stromal opacities of different etiology (11%). Endothelial loss from preoperative levels averaged 11% (range, 10%-13%) at 6 months through 10 years after DALK. ECD was unchanged between 6 months postoperatively and the last follow-up visits.

CONCLUSIONS

DALK is a successful form of transplantation in stromal corneal disorders with healthy endothelium, with higher long-term graft survival rates and stable ECD 6 months postoperatively. DALK survival rates do not vary significantly over time.

Long-term outcomes of penetrating keratoplasty for keratoconus with resolved corneal hydrops

PURPOSE

To address the controversial issue of whether the occurrence of corneal hydrops adversely affects the fate of subsequent penetrating keratoplasty (PK), this study compared the long-term outcomes of PK in keratoconic eyes with resolved corneal hydrops with those without prior corneal hydrops.

METHODS

This was a retrospective chart review of 102 eyes of 102 patients with keratoconus who underwent PK. The primary outcome measure was endothelial rejection-free allograft survival and the secondary outcomes were vision, postoperative complications, and histopathologic findings of corneal buttons obtained during PK.

RESULTS

The mean follow-up after PK was 5.5 ± 3.3 years. The Kaplan-Meier endothelial rejection-free allograft survival at 1 and 5 years post-PK were 93.7% ± 4% and 82.6% ± 7%, respectively, in 32 eyes with hydrops and 100% and 98% ± 2%, respectively, in 70 eyes without hydrops (P = 0.04). Multivariate analysis showed that the risk of endothelial rejection episodes was greater in eyes with longer duration of corneal hydrops (P = 0.019) and coexistent ocular allergy (P = 0.012). All rejection episodes were reversed medically and only 1 allograft failed because of postoperative endophthalmitis. More than 90% of eyes achieved a visual acuity of better than 20/40. Common postoperative complications were cataract and graft infiltrate. Histopathology in cases of resolved hydrops after intracameral gas showed unique compression artifacts like folding and burial of the broken ends of Descemet membrane in the stroma.

CONCLUSIONS

Although endothelial rejection episodes are more common in eyes with resolved corneal hydrops, long-term allograft survival and visual results after PK in eyes with keratoconus are excellent, irrespective of prior corneal hydrops.

CD8+ T cells suppress viral replication in the cornea but contribute to VEGF-C-induced lymphatic vessel genesis

HSV-1 is the leading cause of infectious corneal blindness in the industrialized world. CD4(+) T cells are thought to be the major leukocyte population mediating immunity to HSV-1 in the cornea as well as the likely source of immunopathology that reduces visual acuity. However, the role of CD8(+) T cells in immune surveillance of the cornea is unclear. Thus, we sought to evaluate the role of CD8(+) T cells in ocular immunity using transgenic mice in which >98% of CD8(+) T cells are specific for the immunodominant HSV-1 epitope (gBT-I.1). We found a significant reduction in virus, elevation in HSV-specific CD8(+) T cell influx, and more CD8(+) T cells expressing CXCR3 in the cornea of transgenic mice compared with those in the cornea of wild-type controls yet similar acute corneal pathology. However, by day 30 postinfection, wild-type mice had drastically more blood and lymphatic vessel projections into the cornea compared with gBT-I.1 mice, in which only lymphatic vessel growth in response to VEGF-C could be appreciated. Taken together, these results show that CD8(+) T cells are required to eliminate virus more efficiently from the cornea but play a minimal role in immunopathology as a source of VEGF-C.

Endothelial cell counts after Descemet's stripping automated endothelial keratoplasty versus penetrating keratoplasty in Asian eyes

Background

The purpose of this study was to compare endothelial cell counts after Descemet’s stripping automated endothelial keratoplasty (DSAEK) and penetrating keratoplasty in Asian eyes.

Methods

This was a retrospective study of patients from our prospective Singapore Corneal Transplant Study cohort who received corneal transplantation in 2006–2008. We compared eyes that underwent DSAEK or penetrating keratoplasty for Fuchs’ endothelial dystrophy or pseudophakic and aphakic bullous keratopathy. Clinical data, and donor and recipient characteristics were recorded. Of 241 patients who met our inclusion criteria, 68 underwent DSAEK and 173 underwent penetrating keratoplasty. The main outcome measure was endothelial cell loss at 1 year. Secondary outcome measures were graft survival and visual outcomes at 1-year follow-up.

Results

There were no significant differences in baseline characteristics of patients between the treatment groups. Percent endothelial cell loss at 1-year follow-up was greater in penetrating keratoplasty eyes (40.9% ± 2.9%) compared with DSAEK eyes (22.4% ± 2.3%; P < 0.001). DSAEK-treated eyes had significantly superior uncorrected visual acuity (mean difference = 0.42 ± 0.0059; P < 0.001) and best spectacle-corrected visual acuity (mean difference = 0.14 ± 0.032; P < 0.001) as compared with penetrating keratoplasty-treated eyes. Penetrating keratoplasty-treated eyes had worse astigmatism as compared with DSAEK-treated eyes (−3.0 ± 2.1 versus −1.7 ± 0.8; P < 0.001). Graft survival at 1 year was comparable in both groups, ie, 66/68 (97.0%) DSAEK-treated eyes versus 158/173 (92.0%) of penetrating keratoplasty-treated eyes had clear grafts (P = 0.479).

Conclusion

We report lower percent endothelial cell loss comparing DSAEK and penetrating keratoplasty at 1-year follow-up in Asian eyes, with comparable graft survival rates in both groups.