Penetrating Keratoplasty Versus Deep Anterior Lamellar Keratoplasty in Children and Adolescents With Keratoconus

Triple Procedure: A Stepwise Combination of Deep Anterior Lamellar Keratoplasty and Cataract Surgery

PURPOSE

The aim of this study was to evaluate clinical outcomes of the combined surgery (triple procedure) of deep anterior lamellar keratoplasty (DALK), phacoemulsification, and intraocular lens (IOL) implantation using a new surgical strategy.

METHODS

The study included 43 eyes of 43 patients who underwent a triple procedure. Twenty-six eyes with good visibility through the cornea underwent phacoemulsification before the stromal dissection. Seventeen eyes with bad visibility underwent the DALK procedure first until achieving enough visibility to perform the lensectomy. IOL power calculation was performed for a postoperative estimated flat keratometry of 43.5 and aiming to avoid hyperopic postoperative refraction. The postoperative visual examination included uncorrected and corrected distance visual acuity (CDVA) measurements and manifest refraction.

RESULTS

The mean follow-up time after suture removal was 3.06 ± 2.14 years. Mean CDVA significantly changed from 0.86 ± 0.56 logMAR preoperatively to 0.37 ± 0.28 logMAR in the last visit ( P < 0.0001). The percentage of eyes with CDVA ≤0.3 logMAR changed from 6.9% preoperatively to 62.8%. No eyes lost lines of vision after surgery, and 80% experienced an improvement of 2 or more lines. The safety index was 2.2. The mean postoperative refractive sphere was +0.13 ± 2.04 D, and the postoperative refractive cylinder was -4.02 ± 2.24 D. Only 2 cases (4.65%) obtained postoperative hyperopic astigmatism. No intraoperative complications were found.

CONCLUSIONS

Combined surgery of DALK, phacoemulsification, and IOL implantation is an effective and safe procedure. Depending on the corneal transparency, different surgical strategies can be established to provide more efficacy and safety.

Main issues in deep anterior lamellar keratoplasty: A systematic narrative review

Deep anterior lamellar keratoplasty (DALK) has emerged as a transformative approach in managing corneal pathologies, notably keratoconus (KC), providing a viable alternative to penetrating keratoplasty (PK). This systematic review explores the intricacies of DALK, comparing its preoperative, intraoperative, and postoperative considerations with PK. Extensive literature searches revealed a wealth of data regarding DALK's advantages and challenges, with an emphasis on graft survival, visual outcomes, and complications. In the preoperative phase, DALK showcases its versatility, catering to a wide spectrum of patients, including those with KC and ocular surface disorders. Intraoperatively, it offers innovative techniques to address emphysema, bubble formation, and Descemet's membrane perforation, all while maintaining a strong focus on patient-centered outcomes. Postoperatively, DALK's lower rejection rates and decreased complications underscore its potential superiority over PK, although unique challenges such as graft failure from nonimmunologic factors demand vigilant management. This comprehensive review not only serves as a valuable resource for ophthalmic surgeons but also sheds light on the evolving landscape of corneal transplantation, highlighting DALK's role as a transformative force in the field.

Diagnosis and management of keratoconus in the paediatric age group: a review of current evidence

The diagnosis and management of keratoconus in the paediatric age group presents additional challenges to those encountered in adults. The most significant of these, encountered in some young patients, are delayed presentation of unilateral disease, more advanced disease at diagnosis, difficulty in obtaining reliable corneal imaging, faster rates of disease progression and challenges in contact lens management. The stabilisation effect of corneal cross-linking (CXL), more extensively studied in adults with randomised trials and long-term follow-up, has been much less rigorously examined in children and adolescents. The high heterogeneity of published studies in younger patients, particularly in the choice of tomography parameters designated as primary outcome measures and the definitions of progression, indicates that improved standardisation for future studies on CXL will be necessary. There is no evidence that corneal transplant outcomes in young patients are poorer than those in adults. This review provides a current perspective on the optimal diagnosis and treatment of keratoconus in children and adolescents.

Comparison of Deep Anterior Lamellar Keratoplasty and Penetrating Keratoplasty in Keratoconic Eyes With Previous Hydrops-Related Corneal Scar

PURPOSE

This study aimed to compare the outcomes of deep anterior lamellar keratoplasty (DALK) and penetrating keratoplasty (PK) procedures in keratoconic eyes with a previous hydrops-related corneal scar.

METHODS

In this retrospective study, the medical records of patients who had hydrops-related corneal scarring and underwent keratoplasty surgery were reviewed. Patients treated with DALK were classified as group 1, and patients treated with PK as group 2. Preoperative and postoperative best-corrected visual acuity, central corneal thickness, keratometry (K), and refractive error values of each group were recorded and compared.

RESULTS

Seventy-eight eyes (41 in group 1 and 37 in group 2) were included in this study. The mean follow-up period of the patients was 37.7 ± 30.0 months in group 1 and 51.2 ± 29.4 months in group 2 ( P = 0.06). The preoperative and postoperative best-corrected visual acuity and central corneal thickness values were statistically similar in both groups (each P value >0.05). Keratometry values (K1 and mean keratometry) were significantly steeper in group 1 ( P1 = 0.02 and P2 = 0.03, respectively). Descemet membrane perforation was experienced in 7 (4 macroperforation and 3 microperforation; 15.6%) of 45 eyes that planned to perform DALK. These 4 eyes with macroperforation underwent PK and were excluded from the study. When all postoperative complications were assessed, although the total complication rate was 21% after DALK, it was 43% after PK ( P = 0.04).

CONCLUSIONS

DALK with a big-bubble technique is a feasible surgery in eyes with corneal scarring due to previous hydrops and is comparable with PK in terms of visual and refractive outcomes. This study suggests that DALK, which is safer than PK with less postoperative complication rates, should be the primary surgical option to avoid serious complications in keratoconic eyes with hydrops-related corneal scarring.

Diagnosis and Management of Keratoconus-A Narrative Review of Clinicians' Perspectives

This review discusses the current practices, attitudes, and trends in diagnosing and managing keratoconus (KC) in adults and children by optometrists and ophthalmologists in order to highlight the differences on a global scale. Two independent reviewers searched the electronic databases and grey literature for all potential articles published from 1 January 2000 to 1 June 2022 on management of KC. Keywords used in searches included "keratoconus", "diagnosis", "management", "treatment", "attitude", "practices", "opinion", "optometrist", "ophthalmologist", "consensus", and "protocol". A total of 19 articles was included in this review-12 from the database search and seven from the grey literature. Although a common stepwise approach of non-surgical management was noted, there were differences in the rates of prescribing rigid gas permeable lenses. Furthermore, while clinicians agreed on the need for early diagnosis, the timeline and type of referral varied significantly. A similar discordance was found in the milestones for surgical intervention and preferred surgical techniques. Practice patterns in keratoconus diagnosis and management vary throughout the world. Multiple recommendations and suggestions to minimise the differences have been provided in the literature, with the main themes being improvement in education, interdisciplinary patient care, and further research to reach consensus.

Combined Corneal Transplant, Glaucoma Drainage Implantation, and Pars Plana Vitrectomy Outcomes in a Pediatric Population

PURPOSE

The combination of glaucoma drainage device (GDI), pars plana vitrectomy (PPV), and corneal transplantation is well reported in adults. However, little is known about the outcomes of such combined procedures in pediatric patients. We present a retrospective, single-center study to evaluate the safety and outcomes of concurrent GDI and/or PPV with corneal transplantation in patients 18 years and younger.

METHODS

Retrospective chart review of pediatric patients (aged 0-18 years) who received either corneal transplants or keratoprosthesis in combination with at least 1 additional procedure (either GDI and/or PPV) at the Illinois Eye and Ear Infirmary, Chicago, IL, between 2003 and 2017. Primary outcomes included vision, intraocular pressure, and cup-to-disc ratio (C/D). Secondary outcomes included the number of repeat surgeries and intraoperative and postoperative complications.

RESULTS

Thirty-six patients were included with a mean age of 8.4 years and an average follow-up of 49.7 months. Nineteen patients received corneal surgery, GDI, and PPV; 4 received corneal and GDI surgery; and 13 received corneal and PPV surgery. Of the 19 patients with all 3 procedures, 48% experienced an increase in vision with an average improvement of 0.9 lines at the last follow-up. Intraocular pressure decreased by an average of -7.2 mm Hg for all groups. Fifty-three percent of all patients experienced complications.

CONCLUSIONS

Combined keratoplasty, GDI, and PPV seems to be effective in the management of complex pediatric eye disease. However, owing to the high risk of complications in this vulnerable patient population, careful consideration must be taken when determining a patient's surgical candidacy for combined cornea/glaucoma/retina procedures.

Corneal aberrations, densitometry on scheimpflug imaging, and visual acuity after deep anterior lamellar keratoplasty

PURPOSE

To evaluate visual acuity, corneal aberrations, and densitometry post deep anterior lamellar keratoplasty (DALK).

METHODS

Twenty-five eyes of 25 patients who underwent DALK for corneal stromal diseases with normal endothelium were enrolled in a prospective interventional study. Evaluation for corneal aberrations and densitometry postoperatively was performed using Scheimpflug imaging at 6 months. Anterior Segment Optical Coherence Tomography (ASOCT) was done for host-graft morphology. Correlation analysis of postoperative best-corrected visual acuity with corneal aberrations and corneal densitometry (CD) was performed.

RESULTS

Big bubble deep anterior lamellar keratoplasty (BB-DALK) was successful in 18 patients, while 7 eyes underwent manual dissection due to failed BB (Big Bubble) technique. The mean BSCVA was 1.35 ± 0.46 logMAR units pre-operatively which improved to 0.36 ± 0.19 logMAR units post DALK at 6 months (P < 0.001). The mean Root Mean Square (RMS) (μm) of the magnitude of total corneal aberrations, HOA and LOA from central 6mm zone of cornea were 14.6 ± 9.2, 4.7 ± 2.9, and 13.8 ± 8.8, respectively. The mean anterior (120μm), central and posterior corneal (60μm) densitometry in 0-2mm zone were 25.8 ± 7.7 GSU, 18.7 ± 4.16 GSU and 10.09 ± 3.9 GSU respectively. A statistically significant correlation of postoperative residual stromal bed thickness, total corneal HOA, LOA, total corneal aberrations, HOA front and posterior corneal densitometry (0-2mm zone) with postoperative BSCVA was found.

CONCLUSION

Though there is a significant improvement in BSCVA after DALK, the quality of vision in terms of aberrometry and densitometry is suboptimal, especially in cases undergoing manual DALK compared to those undergoing big bubble formation.

10-year experience with lamellar keratoplasty for the surgical Management of Paediatric Corneal Diseases

PURPOSE

To evaluate the outcomes of various lamellar keratoplasty techniques performed at our Institution in children aged 14 years or younger over the last decade.

METHODS

This single-centre study reviewed 72 eyes that underwent lamellar keratoplasty for various indications. Deep anterior lamellar keratoplasty (DALK) was performed in 19 eyes, mushroom penetrating keratoplasty (PK) in 27 eyes and Descemet stripping automated endothelial keratoplasty (DSAEK) in 25 eyes. The main outcome measures included best spectacle-corrected visual acuity (BSCVA), complications and rate of graft failure which was defined as any graft requiring repeat transplantation.

RESULTS

Best spectacle-corrected visual acuity (BSCVA) significantly improved after DALK, mushroom PK and DSAEK (all p < 0.05), with 50%, 60% and 56% of eyes reaching ≥20/40, respectively. Stromal rejection was observed in 1 eye (5.3%) after DALK, whilst endothelial rejection occurred in 1 eye after mushroom PK (3.7%) and 1 eye after DSAEK (4.0%). Overall survival was 100% after DALK (mean follow-up: 23.0 months), 92.8% after mushroom PK (mean follow-up: 42.3 months) and 96.0% after DSAEK (mean follow-up: 33.6 months).

CONCLUSION

Deep anterior lamellar keratoplasty (DALK), mushroom PK and DSAEK offer good visual outcomes for children with corneal pathology, with low rates of immunological rejection and graft failure.

A New Pre-descemetic Corneal Ring (Neoring) in Deep Anterior Lamellar Keratoplasty for Moderate-Advanced Keratoconus: A Pilot 2-Year Long-Term Follow-Up Study

Purpose: To assess the outcomes of implanting a new polymethylmethacrylate (PMMA) ring (Neoring; AJL Ophthalmic) in pre-descemet deep anterior lamellar keratoplasty (PD-DALK) procedure for moderate-advanced keratoconus.

Methods: This prospective study included 10 eyes of 10 patients with moderate-advanced keratoconus who underwent PD-DALK with Neoring implantation. Neoring was implanted in a pre-descemetic pocket. The post-operative examination included refraction, corrected distance visual acuity (CDVA), corneal tomography, and endothelial cell density (ECD). The root mean squares (RMSs) for coma-like aberrations and spherical aberration were evaluated for a pupil size of 4.5 mm. The junctional graft (Tg) and host (Th) thicknesses were measured. The post-operative follow-up was 24 months.

Results: Post-operative CDVA was 0.82 ± 0.14 (decimal scale), 100% of the eyes achieved a CDVA of 0.7 (decimal scale). The refractive cylinder was −2.86 ± 1.65 2-years after surgery. No eyes had a post-operative refractive cylinder ≥5.00 D and in five eyes (50%), it was ≤2.50 D. At the last visit, the mean keratometry was 45.64 ± 1.96 D, the RMS for coma-like aberrations was 0.30 ± 0.15 μm and spherical aberration was 0.22 ± 0.09. The mean ECD remains without changes over the follow-up (P = 0.07). At the last visit, Tg and Th were 679.9 ± 39.0 and 634.8 ± 41.2 μm, respectively. The thickness of the complex (host-Neoring) was 740.6 ± 35.6 μm. In all cases, this thickness was thicker than Tg.

Conclusion: The results of this study suggest that PD-DALK along Neoring implantation is a viable, effective, and safe option to optimize the post-operative results for moderate-severe keratoconus.