Five-year Outcomes of Converted Mushroom Keratoplasty from Intended Deep Anterior Lamellar Keratoplasty (DALK) Mandate 9-mm Diameter DALK as the Optimal Approach to Keratoconus

Mushroom Penetrating Keratoplasty: A Narrative Review

While full-thickness penetrating keratoplasty (PK) has seen a decline in favor of partial-thickness techniques like endothelial keratoplasty (EK) and anterior lamellar keratoplasty (ALK), PK remains indicated for corneal disease involving the entire corneal thickness. Mushroom keratoplasty (MK) is a noteworthy modification of PK, designed to combine the refractive benefits of a large-diameter anterior lamellar graft with the graft survival advantage of limited replacement of the corneal endothelium. Leveraging the use of a microkeratome, the MK donor graft can be prepared by microkeratome dissection, thereby achieving a central interface compatible with 20/20 Snellen vision. This review explores the various surgical techniques, visual outcomes, graft survival rates, and complication rates associated with MK for various indications.

Addition by Subtraction: Reversing Epikeratophakia and Stromal Scarring in a Patient With Myopia Magna

PURPOSE

To describe a three-phase surgical approach for managing progressive visual decline in a patient with myopia magna and a history of epikeratophakia.

METHODS

A 55-year-old woman with previous epikeratophakia surgery in both eyes experienced progressive visual deterioration. The three-phase approach included: (1) removal of the epikeratophakia lenticule, (2) cataract extraction with intraocular lens implantation, and (3) transepithelial topography-guided photorefractive keratectomy (trans-PRK). Preoperative and postoperative refraction, corneal topography, and visual acuity were assessed.

RESULTS

After trans-PRK, the right eye exhibited regularization of the corneal surface, with a final best spectacle-corrected acuity of 0.15 logMAR. A similar two-phase approach without lenticule removal was applied to the left eye, resulting in improved visual outcomes.

CONCLUSIONS

A three-phase surgical approach combining lenticule removal, cataract surgery, and topography-guided PRK offers a potential pathway for visual improvement in patients with phakic postepikeratophakia.

Outcomes of Corneal Transplantation for Herpetic Keratitis: A Narrative Review

Herpes simplex virus (HSV) is one of the most common etiologic agents of corneal disease and a significant cause of corneal blindness worldwide. Although most cases can be successfully managed with medical therapy, HSV keratitis associated with visually significant stromal scarring often requires corneal transplantation for visual rehabilitation. While penetrating keratoplasty (PK) represented the traditional keratoplasty technique, the past few decades have seen a shift towards lamellar keratoplasty procedures, including deep anterior lamellar keratoplasty and mushroom keratoplasty. This paper describes the current surgical techniques and perioperative antiviral prophylaxis regimen for herpetic keratitis and reviews their postoperative clinical outcomes.

Deep Anterior Lamellar Keratoplasty Using Dehydrated versus Standard Organ Culture-Stored Donor Corneas: Prospective Randomized Trial

PURPOSE

To compare the outcomes of deep anterior lamellar keratoplasty (DALK) using dehydrated versus standard organ culture-stored donor corneas for eyes with keratoconus.

DESIGN

Prospective, randomized, single-center trial conducted in Italy.

PARTICIPANTS

Adult patients (age ≥ 18 years) with keratoconus scheduled for elective DALK.

METHODS

Patients undergoing successful type 1 bubble pneumatic dissection using a standard DALK technique were randomized during surgery to receive either dehydrated (n = 30) or standard organ culture-stored (n = 30) donor corneas.

MAIN OUTCOME MEASURES

The primary study outcome was best spectacle-corrected visual acuity (BSCVA) 12 months after surgery. Secondary outcomes were refractive astigmatism (RA), endothelial cell density (ECD), and complication rates.

RESULTS

Postoperative BSCVA did not significantly differ between groups at both time points: mean difference at 6 months was 0.030 logarithm of the minimum angle of resolution (logMAR; 95% confidence interval [CI], -0.53 to 0.10 logMAR; P = 0.471) and at 12 months was -0.013 logMAR (95% CI, -0.10 to 0.08 logMAR; P = 0.764). No significant differences between groups were observed in terms of postoperative RA and ECD at all time points. In the first 3 days after DALK, an epithelial defect was present in 10 patients (33%) in the organ culture cornea group and in 29 patients (97%) in the dehydrated cornea group. Complete re-epithelialization was achieved by day 7 in all patients (100%) in both groups.

CONCLUSIONS

The study provides evidence that the use of dehydrated corneas is noninferior to the use of standard organ culture donor corneas for DALK. Corneal tissue dehydration represents a viable solution that can allow long-term cornea preservation and avoid wastage of unused corneas.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Outcomes of large-diameter deep anterior lamellar keratoplasty and converted two-piece mushroom penetrating keratoplasty for herpetic corneal scars

PURPOSE

To report the clinical outcomes of large diameter deep anterior lamellar keratoplasty (DALK) and converted two-piece microkeratome-assisted mushroom keratoplasty (MK) for herpetic corneal scars.

METHODS

In this single-centre study, large diameter (9 mm) DALK was attempted in consecutive patients with herpetic corneal scars. In case of macroperforation or unsatisfactory clearance of the optical zone, the procedure was intraoperatively converted to two-piece microkeratome-assisted MK. Outcome measures were best spectacle-corrected visual acuity (BSCVA), refractive astigmatism, endothelial cell density (ECD), immunologic rejection, herpetic recurrence and graft failure rates in the two groups.

RESULTS

DALK was successfully performed in 98 of 120 eyes, while the remaining 22 eyes required intraoperative conversion to MK. At 5 years, mean logMAR BSCVA was 0.10 ± 0.12 in the DALK group and 0.09 ± 0.15 in the MK group (P = 0.75). Refractive astigmatism at 5 years was 2.8 ± 1.4 D in the DALK group and 3.0 ± 1.7 D in the MK group (P = 0.67). ECD was higher in the DALK group than in the MK group at all time points (P < 0.001), with a mean annual cell loss of 10.9% after MK and 4.2% after DALK. The 5-year risk for immunologic rejection (DALK: 3%, MK: 5%, P = 0.38), herpetic recurrence (DALK: 6%, MK: 9%, P = 0.38), and graft failure (DALK: 4%, MK: 5%, P = 0.75) were comparable in both groups.

CONCLUSION

Large diameter (9 mm) DALK yields excellent visual and clinical outcomes in eyes with herpetic corneal scars. In case of intraoperative complications, DALK can be converted to two-piece microkeratome-assisted MK to maximize the refractive benefit of a large diameter graft while minimizing the risk of endothelial failure.

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.

Large-diameter deep anterior lamellar keratoplasty: A narrative review

Deep anterior lamellar keratoplasty (DALK) involves the selective replacement of diseased corneal stroma while preserving healthy unaffected endothelium. While DALK has failed to gain widespread popularity, improved visual and refractive outcomes of large-diameter grafts, which patients directly perceive following suture removal, may represent a compelling reason to shift toward DALK. Since the unaffected host endothelium is retained, DALK offers the opportunity to use large-diameter grafts, which reliably achieves maximum visual potential without an increased risk of immune-mediated stromal rejection. In this narrative review, we evaluate the current evidence on large-diameter DALK including surgical technique and clinical outcomes.

Outcomes of Conventional 8.0-mm Versus Large 9.0-mm Diameter Deep Anterior Lamellar Keratoplasty for Keratoconus

PURPOSE

The purpose of the study was to compare the clinical outcomes of large 9.0-mm diameter and conventional 8.0-mm big-bubble deep anterior lamellar keratoplasty (DALK).

METHODS

In this comparative, retrospective interventional case series, medical records of 124 cases of large 9.0-mm diameter DALK from January 2017 to December 2019 and 133 conventional 8.0-mm DALK from January 2014 to December 2016 performed by a single surgeon for the indication of keratoconus were reviewed. Main outcome measures were best spectacle-corrected visual acuity (BSCVA), refractive astigmatism (RA), and postoperative complication rates.

RESULTS

Postoperative logarithm of the minimum angle of resolution BSCVA did not significantly differ between 9.0-mm and 8.0-mm DALK at any time points. Although the cumulative percentage of eyes achieving Snellen BSCVA of 20/40 or better was comparable between groups (9.0-mm DALK: 93%, 8.0-mm DALK: 90%, P = 0.571), the cumulative percentage of eyes achieving 20/20 or better (9.0-mm DALK: 44%, 8.0-mm DALK: 26%, P = 0.01) and 20/25 or better (9.0-mm DALK: 74%, 8.0-mm DALK: 59%, P = 0.03) was significantly higher in the 9.0-mm DALK group. RA was significantly lower in the 9.0-mm DALK group compared with the 8.0-mm DALK group during all time points (P < 0.001). The percentage of eyes with RA less than or equal to 4.0 D was significantly lower in the 9.0-mm DALK patients (90%) compared with in 8.0-mm DALK group (72%) (P = 0.002). Postoperative complication rates were similar between groups.

CONCLUSIONS

Compared with conventional 8.0-mm DALK, large 9.0-mm DALK can provide superior visual outcomes at higher levels of Snellen BSCVA and significantly lower degrees of astigmatism without an increased risk of immune rejection and graft failure.

Post Penetrating Keratoplasty Ectasia: Incidence, Risk Factors, Clinical Features, and Treatment Options

BACKGROUND: Corneal transplantation in keratoconus (KC) patients is generally considered to be successful with a high grade of patient satisfaction. Long-term studies suggest a 6% to 11% probability of KC recurrence manifested by keratometric instability and progressive corneal ectasia. METHODS: We propose to review the frequency, risk factors for the development, and the surgical options for the correction of high irregular astigmatism due to late graft ectasia following penetrating keratoplasty (PK). RESULTS: Post-keratoplasty ectasia is characterized by increasing corneal steepening with myopic shift and high irregular astigmatism, developing years or decades after PK, mostly occurring in KC patients. Contact lenses may adequately improve the visual acuity; however, because these patients are often elderly and intolerant to hard contact lenses, ultimately a surgical correction is proposed to the patient. Compressive suture and corneal wedge resection may improve corneal astigmatism, but the outcomes are unpredictable and often temporary. For this reason, a larger PK graft is often proposed for surgical rehabilitation with the consequence of removing more of the recipient’s healthy endothelium and exposing the patient to a renewed immunogenic stimulus and short-term graft failure for endothelial decompensation. More recently, lamellar keratoplasty using various techniques has been proposed as an alternative to PK in order to maximize the visual outcomes and minimize the complications. CONCLUSIONS: Management of advanced corneal ectasia is a significant challenge for corneal surgeons. Many surgical approaches have been developed, so there is a large arsenal of surgical operations to correct post-PK ectasia. Among them, large-diameter anterior lamellar keratoplasty may be a viable, safer, and effective alternative to PK for the correction of post-keratoplasty ectasia.

Deep Anterior Lamellar Keratoplasty: Current Status and Future Directions

ABSTRACT

Deep anterior lamellar keratoplasty (DALK) involves selective replacement of diseased corneal stroma while preserving normal healthy endothelium. Despite several well-recognized advantages, the uptake of DALK has remained sluggish with an adoption rate that has plateaued over the past decade. Misconceptions such as the rarity of complications of penetrating keratoplasty, lack of standardization of the DALK technique, and limited substantial benefit in visual and refractive outcomes are frequently cited as arguments against performing DALK. This brief review discusses the recent findings that refute these perceived barriers; describes contemporary techniques, tools, and modifications in the surgical approach; and evaluates the evidence regarding the clinical outcomes of DALK.

Long-Term Outcomes of Two-Piece Mushroom Keratoplasty for Traumatic Corneal Scars

PURPOSE

To report the outcomes of 2-piece microkeratome-assisted mushroom keratoplasty (MK) for eyes with full-thickness traumatic corneal scars and otherwise functional endothelium following corneal penetrating injury.

DESIGN

This was an interventional case series.

METHODS

In this single-center study, 41 consecutive eyes with traumatic corneal scars that underwent 2-piece microkeratome-assisted mushroom keratoplasty were evaluated. The 2-piece mushroom graft consisted of an anterior lamella 9 mm in diameter and a posterior lamella 6 mm in diameter. Outcome measures were best spectacle-corrected visual acuity (BSCVA), refractive astigmatism (RA), endothelial cell density, and postoperative complication rates.

RESULTS

Of the 41 total cases, 38 eyes (93%) reached Snellen vision ≥20/100, 36 (88%) reached ≥20/60, 29 (71%) reached ≥20/40, and 13 (32%) reached ≥20/25 2 years following MK. Excluding eyes with vision-impairing comorbidities, baseline logMAR BSCVA (1.41 ± 0.73) significantly improved annually during the first 2 years (P < 0.001), reaching 0.16 ± 0.13 at year 2, which subsequently remained stable up to 10 years (P = .626). The RA exceeded 4.5 diopters in 2 cases (5%) after wound revision for high-degree astigmatism in 5 cases. Endothelial cell loss was 35.1% at 1 year, with an annual decline of 2.9% over 10 years. Elevation in IOP was observed postoperatively in 7 eyes, of which 6 had pre-existing glaucoma. The 10-year cumulative risk for graft rejection and failure was 8.5% and 10%, respectively.

CONCLUSION

Two-piece microkeratome-assisted MK for traumatic corneal scars can allow excellent visual rehabilitation with relatively stable ECL and low rates of immunologic rejection and graft failure.

Outcomes of cataract surgery with toric intraocular lens implantation after keratoplasty

PURPOSE

To evaluate the efficacy and predictability of cataract extraction with toric intraocular lens (IOL) implantation after deep anterior lamellar keratoplasty (DALK) or mushroom penetrating keratoplasty (PK).

SETTING

Villa Igea Hospital, Forlì, Italy.

DESIGN

Prospective case series.

METHODS

Toric IOL implantation was offered to patients with cataract, corneal astigmatism >1.5 diopters (D) and regular central corneal topography after complete suture removal. Phacoemulsification was performed through a 2.4 mm scleral tunnel and an enVista monofocal toric MX60T or Eyecryl monofocal toric IOL was inserted in the capsular bag. Main outcome measures were uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction, total prediction error, and IOL misalignment.

RESULTS

37 consecutive patients who had previously undergone either DALK (n = 27, 73%) or 2-piece mushroom PK (n = 10, 27%) were included. All patients completed the 6-month follow-up. The mean toric IOL power was 5.3 ± 1.1 D. Both UDVA and CDVA significantly improved (from 1.02 ± 0.27 to 0.46 ± 0.31 logMAR and from 0.65 ± 0.27 to 0.11 ± 0.12 logMAR, respectively; P < .001). 20 eyes (54%) reached UDVA ≥20/40, whereas 35 eyes (95%) reached a CDVA ≥20/40. Final refractive astigmatism was 0.93 ± 0.87 D, with 35 eyes (95%) within 2 D. Prediction error was ≤1 D in 18 eyes (49%). Absolute IOL misalignment was 3.3 ± 3.5 degrees.

CONCLUSIONS

Toric IOL implantation in postkeratoplasty eyes allowed reduction of refractive astigmatism to predictably low levels with concomitant improved visual outcomes.

[Optical properties of the cornea after different modifications of penetrating keratoplasty]

PURPOSE

Comparative analysis of optical properties of the cornea after different modifications of penetrating keratoplasty.

MATERIAL AND METHODS

The study included 56 patients (56 eyes) divided into three study groups according to the surgery technique. Group I included 17 patients (17 eyes) after one-piece mushroom keratoplasty, group II - 21 patients (21 eyes) after two-piece mushroom keratoplasty and group III - 18 patients (18 eyes) after penetrating keratoplasty. In addition to standard examination methods, before surgery and in the course of the follow-up all patients underwent software-powered corneal densitometry on the anterior segment analyzer (Pentacam HR, "Oculus", Germany), as well as an assessment of the degree and regularity of postoperative astigmatism.

RESULTS

Comparison of the obtained results revealed with a high degree of confidence higher values of the total specific light scattering after two-piece mushroom keratoplasty throughout the entire observation period (p<0.05). At the same time, there was no statistically significant difference in visual acuity between the three study groups (p>0.05). A statistically significant increase in the level of induced astigmatism was revealed after penetrating keratoplasty.

CONCLUSION

The observed increase in light scattering after two-piece mushroom keratoplasty does not lead to a decrease in visual acuity. The interface in the optical zone of the cornea formed by a microkeratome does not affect the degree and regularity of induced astigmatism.

Microscope-Integrated Intraoperative Optical Coherence Tomography-Guided Big-Bubble Deep Anterior Lamellar Keratoplasty

PURPOSE

The purpose of this study was to evaluate the feasibility of microscope-integrated intraoperative optical coherence tomography (OCT) for real-time quantitative analysis of surgical planes in big-bubble deep anterior lamellar keratoplasty (DALK).

METHODS

In this interventional case series, intraoperative OCT-guided big-bubble DALK was performed in 16 consecutive eyes of 16 patients with keratoconus. Trephination depth was measured using the intraoperative OCT caliper tool. Aiming for a depth within 150 μm from the endothelial surface, the trephination groove was extended to a deeper plane using a 15-degree blade. Repeat OCT scans were taken to measure residual stromal thickness before insertion of the DALK probe from the bottom of the extended trephination. Caliper measurements, success rate of pneumatic dissection, and complications were recorded.

RESULTS

After trephination, residual stromal thickness exceeded 150 μm in all eyes and averaged 257.1 ± 42.5 μm. In each case, the initial trephination groove was extended to a depth within 150 μm from the endothelial surface (118.9 ± 27.1 μm). Big-bubble formation was achieved in 12 eyes (75%). Type 1 bubble was obtained in 11 eyes. Perforation requiring conversion to penetrating keratoplasty occurred in 4 eyes during insertion of the cannula into a residual stromal bed of <100 μm (n = 2; 63 and 75 μm) or layer-by-layer dissection (n = 2).

CONCLUSIONS

Quantitative analysis of intraoperative OCT scans can be used to assist decision-making on whether to proceed with pneumatic dissection or extend the trephination groove, thereby facilitating insertion of the injection cannula at the desired stromal depth.

Accuracy of intraocular lens power calculation for cataract surgery after deep anterior lamellar keratoplasty

BACKGROUND

The purpose of this study was to assess the accuracy of intraocular lens power (IOL) formulas for cataract surgery after deep anterior lamellar keratoplasty (DALK).

METHODS

This retrospective study included eyes which had previously undergone DALK and underwent standard phacoemulsification with monofocal IOL implantation between January 2012 and January 2021 at Ospedali Privati Forlì "Villa Igea" (Forlì, Italy). The predicted spherical equivalent (SE) was calculated using the Barrett Universal II, Emmetropia Verifying Optical (EVO), Haigis, Hoffer Q, Hoffer QST, Holladay 1, Holladay II, Kane and SRK/T formulas. Prediction error (PE) was calculated as the actual postoperative SE refraction minus the SE predicted refraction.

RESULTS

Eighty-two eyes of 82 patients were included. The mean PE was negative using all formulas. Friedman test revealed a statistically significant difference of the median absolute PE (MedAE) among the different IOL formulas (P = 0.005). On the basis of the MedAE, the formulas were ranked as follows: SRK/T (0.805 D), Kane (0.810 D), EVO (0.845 D), Hoffer QST (0.847 D), Barrett (0.895 D), Holladay 1 (0.915 D), Haigis (1.010 D) and Hoffer Q (1.070 D) formulas.

CONCLUSIONS

All formulas had a tendency towards a myopic refractive shift in post-DALK eyes. Although the SRK/T, Kane, EVO and Hoffer QST formulas were more accurate, predictability of refractive outcomes was lower than in virgin eyes.

Ultrastructural Alterations of Grafted Corneal Buttons: The Anatomic Basis for Stromal Peeling Along a Natural Plane of Separation

PURPOSE

To examine the ultrastructure of the natural plane of separation in grafted corneas and evaluate the outcomes of stromal peeling.

DESIGN

Interventional case series.

METHODS

In this multicenter study, stromal peeling was attempted in 96 consecutive eyes with unsatisfactory vision following penetrating keratoplasty (PK) for keratoconus (n = 79), herpetic keratitis (n = 11), and granular dystrophy (n = 6). Stromal exchange was performed by (1) 9 mm partial-thickness trephination; (2) creation of a corneal flap across the PK wound; (3) opening of the stromal component of the PK wound until a smooth, translucent natural plane was identified; (4) severing the attachment of the PK scar; (5) stromal peeling along the identified plane; and (6) suturing of donor lamella. Grafted corneas from cases that mandated conversion to PK were processed for transmission electron microscopy.

RESULTS

The natural plane of separation was identified in all cases. Stromal exchange was successfully completed in 84 cases (87.5%). Snellen visual acuity ≥20/40 and ≥20/25 was reached in 93% and 72% of cases at 3 years (n = 49) and 86% and 62% at 4 years (n = 21) postoperatively. Mean endothelial cell loss at 1 year was 6.6% ± 9.5%. Stromal peeling occurred along a plane lined with a continuous layer of keratocytes separating pre-Descemet membrane (DM) stroma, DM, and endothelium from the anterior stroma. Pre-DM stroma was made of poorly organized lamellae containing widely spaced, randomly arranged collagen fibrils.

CONCLUSIONS

Ultrastructural alterations in the stromal microarchitecture of grafted corneas provide evidence of a natural plane of separation identified intraoperatively. Stromal peeling can be successfully performed in post-PK eyes with various stromal pathology.

Sutureless Tectonic Mini-Descemet's Stripping Automated Endothelial Keratoplasty ("mini-DSAEK") for the management of corneal perforations

PURPOSE

To report the outcomes of a new technique, pull-through sutureless 'mini-DSAEK', to manage corneal perforations secondary to different aetiologies including trauma, neurotrophic ulcer following penetrating keratoplasty (PK), herpes simplex keratitis and microbial keratitis.

METHODS

In this retrospective case series, we report the clinical outcomes of five cases of sutureless tectonic mini-DSAEK performed in patients presenting with large corneal perforations to Southend University Hospital between November 2019 and October 2020. One corneal perforation was sufficiently peripheral for the tectonic mini-DSAEK graft to be successfully positioned outside of the central visual axis. Four corneal perforations were central or paracentral for which the tectonic grafts involved the visual axis.

RESULTS

Anterior chambers remained deep and formed with no evidence of leak in all subsequent follow ups in all patients representing 100% tectonic success. All tectonic grafts remained attached except one partially detached graft. One patient underwent uneventful phacoemulsification with intraocular lens implant 8 months after the primary intervention with excellent visual outcome. Two patients underwent two-piece mushroom PK and one patient underwent triple procedure (cataract extraction   +   intraocular lens   +   PK) for visual rehabilitation 2-6 months after the primary intervention with good visual outcome.

CONCLUSION

Sutureless tectonic pull-through mini-DSAEK is a useful technique in the management of corneal perforations, with a number of advantages compared with conventional techniques.

Pneumatic Dissection for Large-Diameter (9-mm) Deep Anterior Lamellar Keratoplasty in Eyes With Previous Anterior Lamellar Keratoplasty

PURPOSE

To evaluate the surgical and 3-year clinical outcomes of modified big-bubble 9-mm deep anterior lamellar keratoplasty (DALK) in eyes with previous ALK (ALK).

METHODS

In this interventional case series, 21 consecutive eyes with unsatisfactory vision after ALK (superficial ALK n = 9; laser-assisted ALK n = 7; and epikeratophakia n = 5) underwent large-diameter (9-mm) DALK. The surgery involved deep trephination based on the anterior segment optical coherence tomography pachymetry measurement at 9-mm diameter, pneumatic dissection from the base of the trephination and limited stromal clearance of the optical zone (6 mm). Main outcome measures were success rates of pneumatic dissection, best spectacle-corrected visual acuity, and complication rates.

RESULTS

Pneumatic dissection with type 1 bubble formation succeeded in 19 (90%) eyes. In the 2 remaining cases, the 6-mm optical zone was cleared by manual dissection. Perforation occurred in one of the latter cases; no procedure was converted to penetrating keratoplasty. One month after complete suture removal, the preoperative mean best spectacle-corrected visual acuity (0.75 ± 0.23 logMAR) improved to 0.09 ± 0.10 logMAR (P < 0.001) and remained stable up to 3 years after surgery. At the final follow-up, refractive astigmatism was ≤4.5 and <6 D in 20 (95%) and 21 (100%) eyes, respectively. Stromal rejection was observed in 2 eyes (10%) and was treated successfully with steroids.

CONCLUSIONS

Even in eyes with previous ALK, pneumatic dissection can be achieved through a modified DALK technique with a low risk of complications and excellent visual and refractive outcomes.

Stromal peeling for deep anterior lamellar keratoplasty in post-penetrating keratoplasty eyes

Background/aims

To evaluate the clinical outcomes of deep anterior lamellar keratoplasty performed by stromal peeling in eyes that have previously undergone penetrating keratoplasty (PK) for keratoconus.

Methods

Standardised stromal exchange included (1) 9 mm trephination of the recipient bed outside the old PK wound, (2) creation of a partial anterior corneal flap through lamellar dissection across the PK wound, (3) opening the stromal component of the old PK wound using blunt-tipped Vannas scissors until a plane of separation is reached, (4) severing the attachment of the PK surgical scar from the recipient host, (5) peeling the stroma of the PK graft from the underlying tissue and (6) suturing the donor anterior corneal lamella prepared by microkeratome dissection (450 µm depth, 9 mm diameter). Main outcome measures were success rate, best spectacle-corrected visual acuity (BSCVA) and endothelial cell loss (ECL).

Results

Of 21 post-PK eyes, stromal exchange succeeded in all but three cases, which were converted to a two-piece mushroom PK. After complete suture removal, mean BSCVA significantly improved from 0.95±0.39 logMAR preoperatively to 0.23±0.17 logMAR (p<0.001). Mean ECL was 5.4±23.2%. Double anterior chamber formation occurred in eight cases (44%), which all resolved after a single re-bubbling.

Conclusion

In post-PK eyes, stromal exchange can be performed by means of simple peeling without deep anterior lamellar dissection of the previous PK graft. Large-diameter (9 mm) repeat keratoplasty through stromal peeling yields excellent visual outcomes and minimal ECL. Double anterior chamber formation may complicate the postoperative course, but prompt intervention allows successful management.

Ten-year outcomes of microkeratome-assisted lamellar keratoplasty for keratoconus

BACKGROUND/AIMS

To report the 10-year outcomes of modified microkeratome-assisted lamellar keratoplasty (LK) for keratoconus.

METHODS

In this single-centre interventional case series, 151 consecutive eyes with keratoconus underwent modified microkeratome-assisted LK. Eyes with scars extending beyond the posterior half of the corneal stroma and preoperative thinnest-point pachymetry value of less than 300 μm were excluded. Outcome measures were best spectacle-corrected visual acuity (BSCVA), refractive astigmatism (RA), endothelial cell density, immunological rejection, ectasia recurrence and graft failure rates.

RESULTS

Baseline BSCVA (0.89±0.31 logarithm of the minimum angle of resolution (logMAR)) significantly improved to 0.10±0.12 logMAR at year 3 (p<0.001), and remained stable up to 10 years. At 10 years, 94% of eyes saw ≥20/40, 61% saw ≥20/25 and 24% saw ≥20/20 Snellen BSCVA. At final follow-up, RA exceeding 4.5 dioptres was observed in 5 cases (4%). Endothelial cell loss was 25±17% at 1 year with an annual decline of 2% over 10 years. The 10-year cumulative risk for immunological rejection and graft failure was 8.5%, and 2.4%, respectively. No case developed recurrent ectasia at 10 years.

CONCLUSION

Modified microkeratome-assisted LK results in stable visual and refractive outcomes with low rates of immunological rejection and graft failure in the absence of recurrence of ectasia for at least 10 years.