الفهرس 
Materials and methodsOnly 14 pages are availabe for public view
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Abstract
The first part of this thesis contains the review of ophthalmic
literature. This is further subdivided into seven chapters.
The first chapter includes donor selection, indications and
technique of PKP. Criteria of selecting good donor material are
mentioned. Evaluation of donor material using slit lamp examination
and specular microscopy are included. Methods of corneal preservation
including short-term, intermediate-term and long-term preservation are
described.
Indications of PKP are mentioned with special reference to the
most common current indications such as aphakic and pseudophakic
bullous keratopathy, regrafting, Fuchs’ endothelial dystrophy,
keratoconus and viral keratitis.
Technique of the operation is described including methods of
donor and recipient preparation and different suturing techniques.
Different types of allograft rejection. their clinical pictures.
management. prognosis. mechanism and immunology are the topic of
the second chapter.
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The third chapter contains the diagnosis, incidence, pathogenesis,
mechanism and management of postkeratoplasty glaucoma.
Improvement in microsurgical techniques and tissue storage has
resulted in a higher rate of clear grafts. However, the high
postkeratoplasty astigmatism remains a major problem against early
visual rehabilitation of patients: Factors affecting postkeratoplasty
astigmatism and methods of optical and surgical correction are
described in the fourth chapter.
The integrity of the corneal epithelium after keratoplasty is vital
for graft survival. The presence of an epithelial defect not only
interferes with vision, but may also increase the risk of rejection,
infection, thinning and perforation. Epithelial defects which is the topic
of the fifth chapter, may occur during storage of the donor cornea
preoperatively, intraoperatively or postoperatively.
Postkeratoplasty infections is of utmost importance because, in
addition to the infectious hazards of any intraocular procedure, PKP
carries several other factors before. during and after surgery that
increase the infectious potentials. Preoperatively, in most cases, the
ocular defence mechanisms are compromised. Intraoperatively, donor
tissue itself may act as a source of infection. Postoperatively. there are
several factors that hinder the eye’s normal protective defences such as
decreased corneal sensation, long-term use of topical corticosteroids,
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loss of epithelium and keeping the corneal sutures in place for long
periods.
Rare postkeratoplasty complications include cystoid macular
oedema. retinal detachment. epithelial downgrowth, iris cysts. wound
dehiscence and expulsive haemorrhage. These are mentioned briefly in
the last chapter.
The second part of the thesis is composed of a clinical study of
thirty one patients for whom PKP was performed. These patients were
17 females and 14 males and their ages ranged between 11-75 years.
Fresh whole globes were used as the donor material for thirty of
our patients. Only, one patient received an eye bank corneoscleral
button preserved in M-K medium.
The indication for PKP among these patients was either optical or
cosmetic. PKP was not performed for tectonic or therapeutic purposes
in any of these patients.
According to the preoperative diagnosis, patients were divided
Into six groups being in order of frequency: leucoma adherent, leucoma
non-adherent. bilateral corneal dystrophy, regrafting, aphakic bullous
keratopathy and descematocele.
All donor grafts. except the eye bank corn eo scleral button. were
trephined from the epithelial side. The donor diameter was either 0.25
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mm or 0.50 rnrn larger than recipient bed in phaklc and aphakic patients
respectively.
Simple PKP was performed for 20 patients (64.5%) while 11
patients (35.5%) underwent combined procedures including cataract
extraction. anterior segment reconstruction. anterior vitrectomy. or
removal of tOL.
the preoperative VISIOnamong patients of this series ranged
ranged betw en P.L. and 6/9. Visual improvement was considered when
the patient ad good useful corrected vision of 6/60 or better. Visual
improvement took place in 67.7% of patients. EXclUding patients whose
indication fOf surgery was only cosmetic. the success rate would have
increased to 17.8%.
10-0 mtnofiIament nylon Sutures on spatulated needles were used
through three ~ifferent suturing techniques. The best visual results were
obtained usina interrupted followed by mixed suturing techniques which
were superior (0 the use of the COntinuous suture alone.
Allografi rejection occurred in eleven (35.5%) of the patients of
this series. In six patients of these eleven (54.5%), rejection. was
reversed medi~ally using topical. subconjunctival. and occasionally
systemic cortic~steroids. The other five patients (45.5%) suffered from
irreversible graft rejection and required later regrafting.
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Glaucoma took place in nine of the 31 patients (29%). Three of
these nine, patients were phakic while the remaining six patients were
aphakic preoperatively or were rendered aphakic postoperatively. Eight
patients (188.9%), suffering from postkeratoplasty glaucoma, were
controllerf medically using carbonic anhydrase inhibitors and timolol
maleate. The only patient who required surgery, was also the only one
,who suffered from epithelial downgrowth and she was phakic.
High postkeratoplasty astigmatism i.e, above 3 diopters was
detected. within the first postoperative month. in 8 patients (25.8%) of
our series, Early selective interrupted suture removal succeeded in
decreasing the astigmatism below 3 diopters in seven patients by the end
of the sixth postoperative month. The eighth patient required surgical.
correction 14 months postoperatively.
Epithelial defects of the graft occurred in 12 of the 31 patients
(38.7%). All of them, except two, healed with no sequelae using medical
treatment. For these two patients, therapeutic contact lenses were
inserted ull the graft ulcer healed completely.
Impending superficial vascularization, along the interrupted
sutures’ 1!racts, was noticed in 9 of 31 patients (29%). Removal of the
blamed interrupted sutures resulted in the stoppage of these vessels,
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Endophthalmitis took place in one patient (3.2%) who was 70
years old and for him combined PKP and extracapsular cataract
extraction had been performed with accidental vitreous loss. The
causative organism was proved to be pseudomonas pyocyaneas.
In summary, there are numerous potential complications of
,keratoplasty many of which can be prevented by careful patient
selection, meticulous surgical techniques, and diligent postoperative
care. Fortunately, PKP is successful and free of complications in 85 to
95% of cases. With advances in astigmatism control, results should
continue to improve in the coming years.