Trephination in Penetrating Keratoplasty

Seitz, Berthold; Langenbucher, Achim; Naumann, Gottfried O.H.

doi:10.1007/3-540-31226-9_10

Cited by 10 publications

(4 citation statements)

References 67 publications

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“…Using the excimer laser for lamellar trephination along metal masks, conversion to PKP can be performed without any disadvantage to the patient [63].…”

Section: Discussionmentioning

confidence: 99%

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Stage-Related Therapy of Corneal Dystrophies

Seitz

Lisch

2011

Developments in Ophthalmology

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Corneal dystrophies typically result in a gradual bilateral loss of vision in a primary 'white eye' - often in conjunction with epithelial defects in later stages. Treatment of corneal dystrophies needs to be stage-related. To ensure a stage-related therapeutic approach, an adequate classification based on clinical, histopathological and genetic knowledge is indispensable. In principle, topical medications, contact lenses and various microsurgical approaches are applicable. In case of predominantly superficial dystrophies of the epithelium, basal membrane and/or Bowman's layer (map-dot-fingerprint, Meesmann, Lisch, Reis-Bücklers, Thiel-Behnke), recurrent epithelial defects may complicate the clinical picture. If conservative therapy with gels/ointments, application of therapeutic contact lenses and/or conventional corneal abrasion are not successful, phototherapeutic keratectomy (PTK) using a 193-nm excimer laser is the method of choice today. PTK can be repeated several times, thus post poning corneal transplantation (lamellar or even penetrating) for a long time. Three major goals may be achieved by PTK depending on the diagnosis: (1) to remove superficial opacities; (2) to regularize the surface and treat irregular astigmatism, and (3) to improve the adherence of the epithelium. In dystrophies with depositions predominantly in the stroma (e.g. granular, lattice, macular, recurrence on the graft), PTK may be a reasonable alternative to anterior lamellar or penetrating keratoplasty (PKP) depending on the exact localization of the lesions. Besides exact determination of the depth of depositions using a slit lamp, a preoperative topography analysis is indispensable. The therapy of endothelial dystrophies depends on diagnosis and age: Fuchs endothelial corneal dystrophy will need corneal transplantation (e.g. when visual acuity drops below 0.4). In contrast, transplantation will only be very rarely necessary in posterior polymorphous corneal dystrophy, but the intraocular pressure has to be checked frequently. Especially in elderly patients with reduced compliance, posterior lamellar keratoplasty - preferably in the form of Descemet stripping automated endothelial keratoplasty - may be performed instead of PKP. In case of congenital hereditary endothelial dystrophy, the best time point of PKP has to be determined with regard to amblyopia (surgery too late) and inadequate follow-up (surgery too early) together with parents and pediatric ophthalmologists on an individual basis. In conclusion, for stage-related therapy of corneal dystrophies, besides contact lenses, PTK and PKP, various techniques of lamellar keratoplasties represent an indispensable enrichment of our corneal microsurgical spectrum today.

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“…Using the excimer laser for lamellar trephination along metal masks, conversion to PKP can be performed without any disadvantage to the patient [63].…”

Section: Discussionmentioning

confidence: 99%

“…A few general technical details concerning PKP need to be addressed [63,73]. 1 Donor topography should be attempted for exclusion of previous refractive surgery, keratoconus/high astigmatism.…”

Section: Techniques Of Penetrating Keratoplastymentioning

confidence: 99%

Stage-Related Therapy of Corneal Dystrophies

Seitz

Lisch

2011

Developments in Ophthalmology

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“…Although our results and others have shown that larger graft size may be advantageous for KC eyes, there may be a limit to the trephination size out of concern that a larger graft could result in a higher rate of immunologic rejection. 5,23,24 Therefore, it has been suggested that for eyes with KC, grafts should be as large as possible for less postoperative ectasia and as small as needed to avoid immunologic rejection. 23,25 Regarding corneal cross-linking, it is unclear whether there would be an advantage to treating a larger area of the cornea to help reduce progression of KC, but no studies on that specific topic are available yet and that further research is needed.…”

Section: Figure 2 Correlation Between Host Trephination Size and Prog...mentioning

confidence: 99%

“…5,23,24 Therefore, it has been suggested that for eyes with KC, grafts should be as large as possible for less postoperative ectasia and as small as needed to avoid immunologic rejection. 23,25 Regarding corneal cross-linking, it is unclear whether there would be an advantage to treating a larger area of the cornea to help reduce progression of KC, but no studies on that specific topic are available yet and that further research is needed.…”

Section: Figure 2 Correlation Between Host Trephination Size and Prog...mentioning

confidence: 99%

Recurrent Keratoconus: Corneal Transplants for Keratoconus Develop Tomographic Ectatic Changes

Miura

Leon

Nahum

et al. 2022

Cornea

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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 6.1 D) and postoperative year 3 and year 5 [56.5 6 6.1 diopter (D) and 58.8 6 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 = 20.52, 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.

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