Globe Rupture Following Penetrating Keratoplasty

PURPOSE

Traumatic globe rupture following penetrating keratoplasty is a life-long postoperative concern. We look at a series of penetrating keratoplasties in one institution and determine the rates of traumatic rupture and the outcomes following rupture. The reasons for persisting wound weakness are reviewed, and recommendations for eye protection based on wound strength are given.

METHODS

A case-control study compared the postsurgical rupture rates for all cases of penetrating keratoplasty to those cases of globe rupture after extracapsular cataract surgery and phacoemulsification. A literature review of corneal wound healing was completed.

RESULTS

Over 10 years 139 penetrating keratoplasties were performed. The incidence of traumatic rupture following keratoplasty was 5.8%. Fifty percent of those with ruptured globes had a visual outcome of hand movement vision or worse. Of the traumatic ruptures, 37.5% occurred in the first postoperative month. The indication for initial keratoplasty did not influence the rupture rate. In comparison, the general rate of penetrating eye injuries in the population was 2.2/100,000 per annum. The rupture rate for extracapsular cataract surgery was 1/221 (0.45%) and 0/6450 for phacoemulsification. Both of these rates were significantly less than after penetrating keratoplasty (P=0.005, P<0.0001).

DISCUSSION

Penetrating keratoplasty cases have a higher rate of globe rupture than other ocular procedures. There are 5 important time periods of wound integrity after penetrating keratoplasty. The highest risk period is the month following surgery, when wound strength is derived almost entirely from sutures. The 18 months following surgery are moderately high risk. The month following removal of sutures is a second high-risk period. In the 6 months following this, the wound has a similar strength to the first postoperative year. Following penetrating keratoplasty the cornea never regains its preoperative strength and remains at risk for traumatic rupture for the remainder of the patient's life.

Black eye drop bottle tips improve compliance

AIM

To determine if dark coloured tips on eye drop bottles facilitate ocular therapy.

METHODS

Eye drop bottles were modified by placing sterile black tape around the bottle tip. Patients on regular timolol therapy were asked to use bottles with the modified tip for one month. They then completed a questionnaire comparing the black tips with the standard tips on the bottle they normally use.

RESULTS

Eighty-eight per cent of patients found the black tipped bottles easier to use than bottles with the standard tip. Sixty-eight per cent of patients had fewer occasions on which they needed to instil a second drop and 30% of patients touched their eyelid less when using the modified bottle tips.

CONCLUSION

Black coloured bottle tips aid ocular therapy. They are easier to use, result in less contact with the eye on instillation and patients note a reduction in need for a second or additional drop. This is likely to improve compliance and reduce contamination. A change in manufacturing practise should be encouraged.

Unilateral versus bilateral medial rectus recession

BACKGROUND

Unilateral medial rectus recession is suitable for some cases of small-angle deviation in esotropia. This approach limits surgery to one eye, leaves other muscles untouched, and should be quicker than bilateral muscle surgery. This study compared the results of a range of medial rectus recessions, both unilateral and bilateral, performed by one surgeon.

METHODS

Data were collected on all pediatric patients who had undergone medial rectus recession, unilateral and bilateral, performed by one surgeon between August 1, 1995, and March 31, 2002. Postoperative deviations were calculated from the short- (2 to 8 weeks) and long-term (6 to 48 months) follow-up visits.

RESULTS

Medial rectus recessions were performed on 107 patients, 56 unilateral and 51 bilateral. After exclusions were made, 45 (80%) of the unilateral procedures and 41 (80%) of the bilateral cases were studied. At long-term follow-up, the mean prism diopter (PD) change in deviation per millimeter recessed (at distance) for unilateral recessions of 5 mm, 6 mm, 7 mm, and 8 mm were 2.3, 2.2, 2.3, and 2.5, respectively. For equivalent bilateral recessions the mean changes in deviation were 4.2, 4.0, 4.3, and 5.0 PD/mm.

CONCLUSION

Unilateral medial rectus recession is a predictable method for surgical correction of small-angle pediatric esotropia. The change in deviation per millimeter of recession after unilateral recession is significantly less than that obtained from equivalent amounts of bilateral recession (P <.01).

Bilateral ptosis caused by localized superficial eyelid amyloidosis

A 70-year-old man had bilateral periorbital eyelid swelling. Eyelid biopsy confirmed amyloid infiltrate. Conjunctival involvement was not clinically apparent. The deposits were subsequently curetted with the use of a transcutaneous upper and lower eyelid blepharoplasty approach and found to be entirely pretarsal. No clinical recurrence of the ptosis was noted, but amyloid may have reaccumulated. We propose that in certain circumstances, debridement of localized amyloid should be considered and reaccumulation may not occur.

Functional and ultrastructural effects of nontypeable Haemophilus influenzae in a hamster trachea organ culture system

A hamster trachea organ culture system was utilized to evaluate quantitatively the effects of a strain of nontypeable Haemophilus influenzae (NTHI) and culture supernatants of the same strain on ciliary activity. Tracheal explants were maintained in organ culture for 96 to 144 h and ciliary activity was observed daily with an inverted microscope. Explants continuously exposed to a strain of NTHI had a progressive decline in ciliary activity which was significantly lower than uninfected controls evaluated concomitantly by 48 h of exposure and thereafter. Histologic studies revealed a progressive degeneration of mucosal cells and exfoliation of ciliated cells. Scanning electron microscopy showed little adherence of NTHI to the mucosal surface. Sterile broth cultures of NTHI and supernatants of organ cultures infected with the same NTHI strain had no adverse effect on ciliary activity. Infected tracheal explants treated with ampicillin 24, 48, or 72 h after continuous bacterial challenge had no significant decline in ciliary activity compared to controls. The lack of adherence and the histologic changes observed when hamster trachea cultures were infected with NTHI suggested a toxin might mediate the damage observed. Broth and organ culture supernatants, however, produced no damage. Therefore, further studies are needed to determine the role, if any, of a toxin in the production of damage to hamster tracheal explants by NTHI.

Fimbriation of Haemophilus species isolated from the respiratory tract of adults

Twenty-two clinical isolates of Haemophilus species were studied within two passages of their original isolation for the presence of fimbriae by negative-staining electron microscopy. Six isolates were identified as fimbriated, including three strains of nontypable Haemophilus influenzae, one strain of Haemophilus parainfluenzae, and two strains of Haemophilus haemolyticus. In fresh isolates of fimbriated strains of nontypable H. influenzae, approximately 40%-50% of cells had fimbriae; after five passages in vitro, less than 1% of the cells had fimbriae. Thus, a variety of Haemophilus species that colonize the human respiratory tract can be fimbriated, and this fimbriation is rapidly lost on passage in vitro.