Penetrating keratoplasty for keratoconus: visual and graft survival outcomes

Outcomes of sutured scleral-fixated intraocular lens implantation combined with penetrating keratoplasty

BACKGROUND

The purpose of the study was to assess visual outcomes, complications, intraocular lens (IOL) stability, and corneal status after sutured scleral-fixated intraocular lens implantation combined with penetrating keratoplasty (PKP).

METHODS

This retrospective single-arm cohort study included patients who underwent PKP and sutured scleral-fixated intraocular lens implantation between 2013 and 2018 at the Dhahran Eye Specialty Hospital. The eyes were examined postoperatively at 1, 3, 6, 12, and 24 months. Corneal status, complications, and IOL status were also evaluated periodically, and the number of eyes with a BCVA of > 20/200 was recorded.

RESULTS

Twenty-two eyes from 22 patients were included. The median duration of follow-up was 3 (IQR 1.8; 4.4) years. Reasons for surgery were traumatic globe rupture (six eyes, 27.3%), bullous keratopathy (nine eyes, 40.1%), failed previous graft (five eyes, 22.7%), and corneal scarring (two eyes, 9.1%). Twelve (54.5%) eyes showed a BCVA of > 20/200 (non-blind) at 12 months after surgery and only five (22.7%) before surgery. Twelve months after surgery, 13 patients showed an improvement in BCVA in two lines (59.1%), seven remained the same (31.8%), and 2 deteriorated (9.1%). The indication for surgery (p = 0.2) and the stability of the sutured-scleral fixated IOL (p = 0.8) were not associated with an improvement in BCVA at the final follow-up. The corneal graft remained clear in nine eyes (40.9%) at a median duration of 3 years. The overall average survival period for all corneal grafts was 42.9 months.

CONCLUSIONS

The combination of sutured scleral-fixated intraocular lens implants and PKP is an effective intervention for preserving visual acuity in patients with complex cases. However, the risk of graft failure and then need for repeat transplantation should be taken into consideration.

Keratoconus: imaging modalities and management

Background

Keratoconus (KCN) is characterized by gradual thinning and steepening of the cornea, which can lead to significant vision problems owing to high astigmatism, corneal scarring, or even corneal perforation. The detection of KCN in its early stages is crucial for effective treatment. In this review, we describe current advances in the diagnosis and treatment of KCN.

Methods

This narrative review focuses on recent advancements in the diagnosis and treatment of KCN, especially evolving approaches and strategies. To ensure the inclusion of the most recent literature, relevant publications discussing advanced imaging techniques and treatment options for KCN were extensively gathered from the PubMed/MEDLINE and Google Scholar databases. The following index terms and keywords were used for the online search: keratoconus, diagnosis of keratoconus, advances in the diagnosis of keratoconus, topography or tomography, anterior segment optical coherence tomography, treatment of keratoconus, advances in the treatment of keratoconus, collagen crosslinking, intrastromal ring, keratoplasty, and new techniques in keratoconus.

Results

Various screening methods such as corneal topography, tomography, anterior segment optical coherence tomography, and assessment of corneal biomechanics have been developed to identify KCN in its early stages. After diagnosis, KCN management focuses on preventing disease progression. Corneal collagen crosslinking is a minimally invasive treatment that can slow or stop the progression of the condition. Recent research has also explored the use of copper sulfate eye drops (IVMED-80) as a noninvasive treatment to prevent the progression of KCN. Current treatment options for visual improvement include scleral lenses, intracorneal ring segments, corneal allogeneic intrastromal ring segments, and deep anterior lamellar keratoplasty. Recently, novel alternative procedures, such as isolated Bowman layer transplantation, either as a corneal stromal inlay or onlay, have demonstrated encouraging outcomes. Artificial intelligence has gained acceptance for providing best practices for the diagnosis and management of KCN, and the science of its application is contentiously debated; however, it may not have been sufficiently developed.

Conclusions

Early detection and advancements in screening methods using current imaging modalities have improved diagnosis of KCN. Improvement in the accuracy of current screening or diagnostic tests and comparison of their validities are achievable by well-designed, large-scale, prospective studies. The safety and effectiveness of emerging treatments for KCN are currently being investigated. There is an ongoing need for studies to track progress and evaluate clinicians' knowledge and practices in treating patients with KCN. Artificial intelligence capabilities in management approach considering the currently available imaging modalities and treatment options would best benefit the patient.

Risk factors for corneal graft rejection after penetrating keratoplasty for keratoconus

PURPOSE

To evaluate the association between donor-related factors and the risk of rejection in patients undergoing penetrating keratoplasty (PKP) for keratoconus.

METHODS

A retrospective review was performed of keratoconus patients with no corneal neovascularization who underwent PKP from November 2014 to December 2016 and completed at least two years of follow-up. Preoperative, donor, operative, and postoperative data were collected and analyzed to identify factors leading to corneal graft rejection.

RESULTS

A total of 201 eyes (of 201 patients) that underwent PKP for keratoconus were included. Of these, 22.9% (95% CI 17.6-29.2%) had an episode of graft rejection. The overall graft survival rate was 98.5%. Receipts with a history of corneal transplant in the fellow eye (IRR 1.69, 95% CI 1.01, 2.80; p = 0.044) and those with postoperative stromal neovascularization (IRR 2.51, 95% CI 1.49, 4.21; p = 0.001) had a significantly higher incidence of rejection than those without these features. In univariate analysis, death-to-surgery time and death-to-excision time (DET) showed a weak association with graft rejection (p 0.05 and 0.08 respectively); However, in the multivariable analysis, this significance was lost. Grafts with a death-to-excision time (DET) greater than 8 h had a 0.53X lower risk of rejection compared with grafts with DET within 8 h or less (p = 0.05). Rejection was higher in patients receiving grafts with a preservation time within 7 days or less compared with preservation time greater than 7 days (30.6% vs. 21.2%, respectively, p = 0.291).

CONCLUSION

In the multivariable analysis, none of the donor-related factors were significantly associated with graft rejection; however, short death-to-surgery time may be associated with rejection after PKP. Recipients with a history of PKP in the fellow eye and those who developed corneal neovascularization were also at increased risk of developing rejection after keratoplasty.

The evaluation of corneal topographic parameters with corneal and lens densitometers in pediatric keratoconus

PURPOSE

The aim of this study was to compare corneal and lens densitometric measurements and corneal topographic parameters of pediatric keratoconus patients and healthy individuals.

METHODS

The data of the Pentacam^® HR device and the database of our hospital between 2017 and 2019 were analyzed retrospectively. A total of 80 eyes of 47 keratoconus children (one eye of 14 children and two eyes of 33 children) in the Group KC (n = 80); and 74 eyes of 37 children were assessed in healthy children, Group HC (n = 74). The corneal density was measured manually in full-thickness cornea with a diameter of 2 mm in the corneal apex. The lens density (LD) was measured manually in the pupillary area with a diameter of 2 mm throughout the whole central lens thickness in 3D mode.

RESULTS

The corneal density values were significantly higher in Group KC (12.72 ± 1.68, 1.00 ± 0.34, 16.36 ± 2.32, respectively) compared to Group HC (9.81 ± 1.02, 0.61 ± 0.28, 12.42 ± 1.44, respectively) (p < 0.001). LD-mean and LD-sd measurements were lower in Group KC (7.55 ± 0.48, 0.61 ± 0.49, respectively) compared to Group HC (7.75 ± 0.39, 0.81 ± 0.49, respectively) (p = 0.004, p = 0.014, respectively).

CONCLUSION

It was found that corneal density increased and lens density decreased in pediatric keratoconus patients. These results showed that there may be factors that prevent or delay lens changes in isolated pediatric keratoconus patients.

Descemet stripping automated endothelialkeratoplasty (DSAEK) versus repeat penetrating keratoplasty (PKP) to manage eyes with failed corneal graft

BACKGROUND

Failed corneal graft management is a challenge. Descemet stripping automated endothe.lial keratoplasty (DSAEK) and repeat penetrating keratoplasty (PKP) are two options. Only two studies have compared outcomes of DSAEK and PKP in the management of a failed graft.

OBJECTIVE

To compare the visual outcomes, changes in intraocular pressure (IOP) and complications in eyes with failed corneal grafts that were subsequently managed with DSAEK and PKP.

DESIGN

Retrospective cohort study.

SETTINGS

Tertiary eye hospital of central Saudi Arabia.

PATIENTS AND METHODS

A retrospective chart review was performed for cases managed between 2007 and 2012. Data were collected on the best-corrected visual acuity (BCVA) before and at day 1, 1 week, 4 weeks, 12 weeks, and 24 weeks after intervention. BCVA was compared in patients managed with DSAEK or PKP. Intra- and postoperative complications were compared in both groups.

MAIN OUTCOME MEASURES

Clear graft, vision at last follow up, complications.

RESULTS

There were 15 eyes in the DSAEK group and 30 in the PKP group. The causes of previously failed PKP differed between groups. BCVA at 6 months after repeat surgeries was 20/20 to 20/40 in 4 (27%) eyes in the DSAEK group and in 8 (27%) eyes in the PKP group. The IOP at 6 months was statistically significantly higher in the DSAEK group than the PKP group (P=.006). In DSAEK group, one graft rejection occurred in one eye and graft dislocation in another eye. Seven eyes in PKP group had signs of graft rejection that regressed in 5 eyes following medical management.

CONCLUSIONS

DSAEK and PKP for previously failed corneal graft resulted in similar BCVA 6 months after repeat surgery. However, the visual outcomes were less promising with both types of surgeries. The lower complication rate and surgical ease may favor DSAEK over PKP in managing failed grafts.

LIMITATIONS

Small sample, retrospective study.

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.

Comparison of outcomes and complications of deep anterior lamellar keratoplasty and penetrating keratoplasty performed in a large group of patients with keratoconus

PURPOSE

To compare visual acuity, refraction, topography, and complications of deep anterior lamellar keratoplasty (DALK) and penetrating keratoplasty (PKP) performed in patients with keratoconus (KCN).

METHODS

In this retrospective interventional non-randomized clinical study, patients with moderate to severe KCN that underwent either PKP or DALK for optical corrections were enrolled. The final outcome analysis was performed after complete suture removal for both groups of patients. Best corrected visual acuity, spherical equivalent, refractive cylinder, average keratometry, corneal astigmatism, and endothelial cell density as well as early and late complications such as cataract, glaucoma, corneal edema, elevated intraocular pressure without visual field defect or optic disk changes, rejection, loose suture, and re-suturing were compared.

RESULTS

Two hundred and seven eyes were enrolled: 108 eyes underwent DALK, and 99 eyes underwent PKP for keratoconus. The mean follow-up time was 28.06 ± 12.62 months for DALK group and 29.29 ± 12.71 months for PKP. The study groups demonstrated comparable final outcome in terms of best corrected visual acuity: 0.25 ± 0.22 LogMAR and 0.28 ± 0.24 LogMAR (p = 0.415), spherical equivalent: -4.80 ± 4.55D and -3.58 ± 3.58D (p = 0.067), refractive cylinder: -3.37 ± 2.00D and -4.00 ± 2.15D (p = 0.061), average keratometry: 45.51 ± 2.30D and 44.85 ± 2.36D (p = 0.077), corneal astigmatism: 4.89 ± 3.07D and 4.63 ± 2.61D (p = 0.569) in DALK (n = 85) and PKP (n = 72), respectively. However, the postoperative endothelial cell density in DALK (n = 61) 2250 ± 450 cell/mm² differs significantly from it in PKP (n = 55) 1795 ± 616 cell/mm² p < 0.001. Eyes that had DALK (n = 99) had significantly more risk of loose suture (RR 5.2) and re-suturing (RR 3.6) than PKP (n = 108). However, the risk of cataract following DALKs was less than PKP (OR 0.4).

CONCLUSION

The vision, refractive error, and corneal astigmatism following DALK and PKP were comparable; however, DALK had lower incidence of long-term complications.

Corneal collagen crosslinking for progressive keratoconus in Saudi Arabia: One-year controlled clinical trial analysis

Aims

To determine the short-term efficacy of corneal collagen crosslinking (CXL) treatment in patients with progressive Keratoconus (KCN) in comparison with no treatment.

Settings and design

This controlled clinical trial study was carried out at a tertiary eye hospital, Eastern Province, Saudi Arabia.

Methods and material

A prospective controlled clinical study of patients being treated for Keratoconus at a tertiary eye care hospital in the Eastern province of Saudi Arabia. 51 eyes of 43 patients with progressive KCN who received corneal collagen crosslinking (treatment group) and 50 eyes of 34 patients with KCN and no treatment (control group) were included in our study. A one year clinical data were collected preoperatively as well as at 1, 3, 6 and 12 months postoperatively for the treatment group patients. A baseline and 1 year clinical data were collected for the control group patients. The short-term efficacy of the treatment in preventing progression of KCN in comparison with no treatment was analysed at one year.

Results

At one year after crosslinking there was significant flattening of the average keratometry by 0.61 D (p = 0.001) [95% CI: 0.25, 0.97] compared to 0.40 D (p = 0.210) steepening in the control group; difference between treatment and control was 1.01 D (p = 0.006) [95%CI: 0.29, 1.72]. Pachymetry in treatment group thinned by 20.21 μm (p < 0.0001) [95% CI: 12.77, 27.66] compared to 0.32 μm (p = 0.912) in the control group. Visual acuity remained stable at the preoperative level of 20/30 (p = 0.397) in the treatment group and 20/40 (p = 0.553) in the control group at one year.

Conclusions

Corneal CXL is an effective treatment for halting the progression of KCN as shown by reduced keratometry and stability of vision.

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.

Mesenchymal stem cells, nanofiber scaffolds and ocular surface reconstruction

Ocular surface defects represent one of the most common causes of impaired vision or even blindness. For treatment, keratoplasty represents the first choice. However, if corneal defects are more extensive and associated with a limbal stem cell (LSC) deficiency, corneal transplantation is not a sufficient therapeutic procedure and only viable approach to treatment is the transplantation of LSCs. When the LSC deficiency is a bilateral disorder, autologous LSCs are not available. The use of allogeneic LSCs requires strong immunosuppression, which leads to side-effects, and the treatment is not always effective. The alternative and perspective approach to the treatment of severe ocular surface injuries and LSC deficiency is offered by the transplantation of autologous mesenchymal stem cells (MSCs). These cells can be obtained from the bone marrow or adipose tissue of the particular patient, grow well in vitro and can be transferred, using an appropriate scaffold, onto the damaged ocular surface. Here they exert beneficial effects by possible direct differentiation into corneal epithelial cells, by immunomodulatory effects and by the production of numerous trophic and growth factors. Recent experiments utilizing the therapeutic properties of MSCs in animal models with a mechanically or chemically injured ocular surface have yielded promising results and demonstrated significant corneal regeneration, improved corneal transparency and a rapid healing process associated with the restoration of vision. The use of autologous MSCs thus represents a promising therapeutic approach and offers hope for patients with severe ocular surface injuries and LSC deficiency.