|Year : 1994 | Volume
| Issue : 4 | Page : 215-217
Postoperative management of corneal graft
Jagjit S Saini
Postgraduate Institute of Medical Education and Research, Chandigarh, India
Jagjit S Saini
Postgraduate Institute of Medical Education and Research, Chandigarh 160 012
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Saini JS. Postoperative management of corneal graft. Indian J Ophthalmol 1994;42:215-7
Corneal transplantation has become a very successful procedure due to advances in eye banking, corneal surgery and postoperative treatment. Corneal grafts are prone to complications which may appear trivial but may lead to corneal graft failure. Familiarity with routine postoperative care and early detection of minor complications prevents this problem. Transparent corneal grafts often need additional procedures to optimise visual and functional recovery. The success of keratoplasty, more than any other ophthalmic surgery, depends on careful and diligent postoperative care. Both the patient and the surgeon must be constantly alert to changes in the eye so that problems can be promptly treated. This section will review the current guidelines for the postoperative care of a patient with corneal graft.
Immediate Postoperative Care
At the completion of suturing of the host-graft junction, an antibiotic and steroid combination may be given subconjunctivally. A short-acting mydriatic (cyclopentolate 1%) is instilled topically and the eye is patched with a gauze pad and a rigid metallic or plastic eye shield. Patients are generally encouraged to have a normal diet and change over to comfortable body posture soon after the surgery. As soon as patients recover from the effects of anaesthesia they are permitted regular activities. It is important, however, to instruct the patient to avoid direct trauma to the eye. In any activity where the patient is not comfortable because of poor vision in the fellow eye or systemic disability, assistance should be taken to prevent any injury to the operated eye.
Many patients may request for a mild analgesic on the first day. Stronger medications are almost never needed, and the need for them should alert the surgeon to the presence of possible complications.
In the eyes suspected to have postoperative rise of intraocular pressure (IOP) including when viscoelastic substances such as sodium hyaluronate have been left in the anterior chamber during surgery, systemic oral acetazolamide 250 mg is administered. There is no routine need for systemic antibiotics after the corneal transplant.
2. Follow-up Care
2.1 Follow-up: Evaluation and Frequency
It is mandatory to evaluate the eye on slit-lamp for wound integrity, epithelial defects, corneal oedema, IOP, iritis, and the possibility of infection on the first postoperative day. If any of these complications manifest or persist, evaluation of the operated eye should be continued on a daily basis for a few more days. As soon as the condition becomes normal, further evaluation may be at the end of a week followed by every two weeks for one month and then every month for the first year. In the absence of any complications, scheduled evaluations at increasing intervals of once or twice a year are adequate.
It is important to emphasize to the patient the danger signals and to report immediately should these problems occur. Each patient should be cognizant of symptoms such as sudden onset of redness of the eye, increasing sensitivity to light (photophobia), loss of vision or clouding of donor cornea, and persistent and increasing eye pain. It may be a good practice to have written instructions delivered to the patient. Since most complications can be successfully treated with early intervention, appropriate instructions to the patient are useful.
2.2 Early Wound Problems
The eye patch is removed on the first postoperative day. During the day time the patient is instructed to wear glasses which may have appropriate optical correction for the fellow eye. It is not always necessary to wear dark glasses. A rigid eye shield must be worn by the patient at night time for 8 weeks.
Wound leaks are rare with current microsurgical techniques but should be looked for carefully. Unusual localised oedema at the host-graft junction, a shallow anterior chamber with or without peaking of the pupil, and low IOP should arouse a suspicion of wound leak which may be confirmed on Siedel's test. Patching and/or a bandage contact lens should be an adequate treatment for minor leaks. However, when the anterior chamber remains collapsed for 48 hours or the leak persists for 4 days, additional sutures should be . placed to close the leak. Iris prolapse should be repaired immediately.
Complete epithelialisation of graft surface usually occurs within 2 to 3 days. If an epithelial defect is persistent, patching of the eye during day time or direct taping of lids is done. For more recalcitrant cases bandage contact lenses or lateral tarsorrhaphy may be required. Epithelial defects need close monitoring because of their potential to cause rejection, infection, thinning and perforation of the graft.
Topical steroid drops are instilled in the operated eye four times a day initially and the frequency is increased or decreased depending on the degree of inflammation. At the end of one month following surgery, most of the patients will need steroid drops two times a day. This dosage of medication is continued for three months. In eyes where inflammatory signs persist, topical steroids may be continued longer. Reversal of graft rejection will need more intensive topical steroids. This may be continued at one drop a day or on alternate days until all sutures are removed.
Topical antibiotics are discontinued at the end of one week and there is no suspicion of infection. Short-acting cycloplegic (cyclopentolate 1%) may be instilled till iritis subsides and may be discontinued after the first week.
In the event of acute redness of the eye, the patient should be advised to initiate topical instillation of antibiotic-steroid combination one hourly.
2.4 Suture Removal
The decision to remove sutures in a corneal transplant is complex yet critical to the final visual outcome and is primarily based on sound clinical judgement. Loose sutures need to be removed as they contribute to immunologic stimulus leading to graft rejection and infection. Although corneal vascularization is usually a sign of wound healing and an indication for suture removal, it may not be a foolproof sign. The timing of suture removal may vary depending on the preoperative pathology and age of the patient. In children, suture removal may be required sometimes as early as one week and in adults with avascular host disease, one may delay suture removal for 12 to 18 months in the absence of other indications. Our preferred method is to cut interrupted sutures at the curve of the suture with a disposable 26-gauge hypodermic needle under slitlamp magnification. The suture is cut on the host cornea and gently teased to facilitate grasping with forceps. With running 10-0 nylon sutures every other loop in the host cornea is first cut, leaving an intact loop that is also grasped in the host tissue and pulled peripherally. It is important that topical antibiotics are instilled for 3 days and the eye is examined 24 to 48 hours after suture removal for epithelial defect, wound override or dehiscence. The dosage of topical steroids should be increased immediately after suture removal and tapered over a 2 to 4 week period.
2.5 Intraocular Pressure
Almost one-third of the eyes develop rise of IOP following penetrating keratoplasty. The incidence in aphakic eyes is higher (42 to 89%). IOP is accurately assessed by Tono-Pen or pneumatic applanation tonometer. Inadequate control of IOP after penetrating keratoplasty is one of the leading causes of graft failure. It is mandatory that IOP be assessed accurately, early and at every visit. Several factors including inflammation, mechanical problems and steroidinduced side-effects can contribute to the rise of IOP. Elucidation of pathogenesis of glaucoma will help application of appropriate therapy. Trabeculectomy with or without antimitotic metabolites may be indicated in eyes when the conjunctiva is mobile. With fewer complications, ease of initial and repeat treatment with Nd: YAG laser is being used more frequently. In places where these facilities do not exist, conventional cyclocryotherapy is very effective particularly in aphakic eyes.
The reported incidence of postkeratoplasty infections ranges from 1.8 to 11.9%. In order to prevent infection, loose or ruptured sutures should be aggressively managed postoperatively. Following suture removal, the eye should be monitored for 48 hours for possible infection. All corneal grafts with persistent epithelial defects should be monitored for healing and infection. The overall prognosis for postoperative infectious keratitis is poor. Careful attention to high-risk factors such as loose, broken sutures and epithelial defects will help prevent postkeratoplasty infections. All postoperative patients should be asked to seek immediate treatment if a white spot is seen on the eye or sticky discharge persists for 24 hours.
2.7 Visual Rehabilitation
Astigmatism remains a major obstacle for visual rehabilitation after penetrating keratoplasty. Selective suture removal has been shown to hasten visual rehabilitation. Keratometry photokeratoscopy, slit-lamp examination and manifest refraction help identification of any tight sutures. Selective suture removal begins at about 6 weeks and only one or two sutures are removed at one time. The cornea is evaluated every 2 weeks for change in contour and further sutures are removed. If astigmatism is still present at the end of 8 to 9 months, incisional arcuate keratotomy in the wound or inside the wound is planned in the steeper meridian which corrects 4-6 D of astigmatism. The incision length and depth should vary , depending upon the type of wound healing that has yielded the astigmatism. Intraoperative keratometry helps to optimise the grading of length and depth of the incision according to the effect achieved during the surgical procedure. Progressive deepening and lengthening of the incision is performed first on one side and then on the other side until keratometer mire is assessed to be spherical. It is not necessary to overcorrect. Additional compression sutures in the flatter meridian may be employed to enhance the effect. In situations where significant astigmatism continues to be an obstacle to visual rehabilitation, more drastic methods of wedge resection, wound revision and repeat keratoplasty may have to be considered. When indicated, radial incisions on the graft may be performed in combination with intraincisional relaxing incisions or arcuate incisions.
As soon as the refraction is observed to have stabilised appropriate glasses or contact lenses are prescribed and this may take 2 to 6 months. Contact lens fitting in a postkeratoplasty eye is not always successful. A rigid gas permeable (RGP) contact lens centred over the graft is ideal but seldom achieved. If the visual acuity is good despite lens decentration, a contact lens is prescribed.
3. Resumption of Activities
In general, near normal activity can be resumed soon after surgery. However, it is necessary to explain to the patient the risk of direct injury to the eye and maintenance of ocular hygiene to prevent infection particularly in the first few weeks after surgery. In the first two weeks, unusual degrees of physical strain should be avoided. Contact sports should be avoided as well as any sports with risk of blunt injury. One could return to normal work after a week unless the work involves significant amount of manual or physical strain.
For long term success following penetrating keratoplasty, it is desirable that both the surgeon and the patient must be constantly alert to the changes in the eye so that problems can be promptly treated. The care of the corneal transplant is a lifelong commitment. Most complications can be successfully reversed and the grafts saved when the problems are detected early and treated. Educating the patient and the referring physician to contact the surgeon immediately about any change in the condition of the eye may be the most important factor in the success or failure of corneal transplant. In our experience, written instructions ensure better compliance.