Summary of the

5^th KPRO Study Group / 8^th International Ocular Surface Society

Joint Meeting

 

 

9^th May 2003

 

Retter Auditorium, Bascom Palmer Eye Institute, University of Miami, School of Medicine, Miami, Florida, USA

 

 

 

Ocular Surface Inflammation as a Threat to Reconstruction and Keratoprosthesis

 

 

The objective of this symposium was to explore the pathogenesis of ocular surface inflammation and how this can affect the success of the complementary techniques, of ocular surface reconstruction and keratoprosthesis, that are required to rehabilitate different subsets of patients with anterior segment blindness.  The meeting brought together clinicians and clinical scientists with expertise in these areas.  There were 4 lectures and 23 papers given through the course of the day. 

 

The opening lecture was given by Professor Stephen Pflugfelder on the topic of Section 1 of the meeting “The role of ocular surface inflammation in tear film disturbance”.  Dr Pflugfelder, with his co-workers De-Quan and Solomon in later papers, showed us in an elegant series of animal experiments, with human correlates, how the pathogenesis of dry eye resulted not only from tear film dysfunction and mechanical factors, but also from inflammation.  He demonstrated how hyperosmolarity in a mouse model and in-vitro could up-regulate IL1b and TNFa, which in turn result in MMP9 up-regulation.  MMP9 has been shown to be present in the human tear film and its role was then demonstrated in the mouse model, where it was shown to be responsible for many of the features of dry eye. 

 

Thomas John then described a case of “sandwich” keratitis under a deep lamellar graft, which has a very different phenotype from the keratitis associated with surface infection, possibly due to the removal of the organisms from antimicrobial influences in the tear film. 

 

Another paper in this section, from Dr Dogru, on the role of inflammation derived from tear film abnormality, showed that pre-term babies have dry eye. 

 

In Section 2, entitled “The role of inflammation derived from the blinking abnormality” Professor Scheffer Tseng, with Pasquale, Espana and Kawakita, raised the problem of lid ocular surface interactions in the extreme case of the ocular disease resulting from Stevens Johnson syndrome. They described how dysfunction of the lid ocular surface interactions potentially cause surface trauma.  They showed how these problems could be addressed by the use of contact lenses, by fornix reconstruction, and amniotic membrane with the use of per-operative Mitomycin C, to reduce fibroblastic activity, and apparently also damp down the inflammatory response.

 

Dr Ken Kenyon then gave the IOSS Guest Lecture entitled “Neurotrophic Keratitis: Current Management Strategies”. He showed how the intelligent application of a step- ladder of management strategies can lead to successful corneal rehabilitation.  He discussed the traditional methods of treatment using lubrication and therapeutic contact lenses for mild (Stage 1) neurotrophic keratopathy, moving on to tarsorrhaphy and ptosis for more severe (Stage 2) disease complicated by epithelial defects and, lastly, the use of conjunctival flaps to manage problems of stromal loss and impending perforation.

 

He then went on to discuss new therapies, including nerve growth factor, the use of amnion and the potential that this tissue has had for supplying nerve growth factor, epidermal growth factor and suppressing TGFb.  Lastly, he described a substantial series of corneal grafts treated with keratoplasty, and an amniotic membrane patch graft, for management of opaque corneas following neurotrophic keratopathy.

 

 

The third section “The role of inflammation derived from the host stroma”, chaired by Professor Eddie Alfonso, moved on to discuss the role of inflammation derived from the host stroma.  With Dr Koyabashi we had an insight into what confocal microscopy has to offer.  This was followed by Dr Takano describing the use of amniotic membrane in reconstructing persistent epithelial defects.  Paolo Rama then reported a series of 31 cases of surface failure treated with ex-vivo expanded limbal stem cell transplantation.  The success rate was 75% for establishing a normal surface.  The reasons for failure were bleeding under the fibrin sheet, which acts as a carrier for the cells, delay of absorption from the carrier and a poor environment, in particular, inflammation, which led to a poor outcome in some cases.  He raised the issues of how much inflammation, in eyes that are often severely damaged, is acceptable, and how we might control it. 

 

In the afternoon, the Bascom Palmer Eye Institute Guest Lecture was given by Professor Claes Dohlman, who summarised the status quo of the collar button keratoprosthesis in the graft failure group.  He showed a video that demonstrated the technique and discussed the improved outcomes that have resulted in the use of large, therapeutic soft contact lenses (which reduce dellen around the edge of the prosthesis), topical fluoroquinolones (as prophylaxis for endophthalmitis) and Ahmed valves (to control what had been intractable glaucoma).

 

Professor Barraquer then gave the Kpro Society’s Guest Lecture and described the history of Strampelli’s osteo-odonto-keratoprosthesis in his institution.  This was followed by a lecture from one of the other major figures in keratoprosthesis surgery, Professor Falcinelli, who described his modifications of the Strampelli procedure, which include a lamellar keratectomy to remove Bowman’s layer, the use of thicker cheek mucosa rather than labial mucosa, a short dental lamina to reduce buccal thinning, a modified Strampelli’s cylinder, reattachment of the periosteum around the tooth with biological glue, removal of the iris, removal of the lens and the use of anterior vitrectomy.  He described 234 eyes operated on between 1973 and 2002, of whom 53 had died and 39 were lost to follow-up.  The reported failure rate was 14%. 

 

Jean-Marie Parel proceeded to describe 3 cases of Michael Roper-Hall’s with very good prolonged visual results following keratoprosthesis surgery carried out several decades previously. 

 

The fourth section was entitled “The role of inflammation derived from the interface between the host tissue and the Kpro”, chaired by Debbie Sweeney, in which Dr Xie discussed the tissue responses to a corneal inlay of perfluoropolyether in both a cat and rabbit model.  Dr Tandon presented the results of osteo-odonto-keratoprosthesis (from Chris Liu in the UK) in 29 cases of inflammatory eye disease, including Stevens Johnson cicatricial pemphigoid and chemical injuries.  Seventy-one percent of patients achieved 20/200 or better, and 57% 20/30 or better.  There was 1 case each of retroprosthetic membrane, retinal detachment and extrusion.

 

Dr Fernandez discussed the outcomes of the Dohlman keratoprosthesis at the Bascom Palmer, followed by Dr Hille reporting the absorption of the dental lamina in osteo-odonto-keratoprosthesis, as demonstrated by high-resolution computer tomography. This was followed by Celia Hicks discussing the results of 50 consecutive cases of AlphaCor corneal implants, and the role of medroxyprogesterone in controlling melts.  Lastly, Dr Stoiber discussed the results of the Supradescemetic synthetic cornea in the rabbit model. 

 

In the last section on clinical experiences of keratoprosthesis, Dr Tandon reported the results of using allografts for OOKP in a series of edentulous patients.  There was a further presentation of the feasibility of the Supradescemetic synthetic cornea in human eye bank eyes from the Bascom Palmer group, and a description of a modified collar button Kpro by Dr White. 

 

**********

 

This was an enjoyable day, with some lively discussion.  The Chairmen of the societies are in the debt of Carmen Puliafito, Chairman of the Bascom Palmer Eye Institute, for hosting the meeting, and to Scheffer Tseng, Debbie Sweeney, Jean-Marie Parel and Eddie Alfonso for their organisational skills.

 

John Dart

Moorfields Eye Hospital

London, UK