Suture abscesses after penetrating keratoplasty.

Eighteen suture abscesses that developed after penetrating keratoplasty in 15 patients were reviewed. The time from keratoplasty to the diagnosis of an abscess ranged from 1 to 53 months with a mean of 21.5 months. In 13 of the 18 cases, the patient was taking topical steroids at the time of diagnosis. All were culture-proven bacterial ulcers, except for one case that had a positive Gram's stain, but no growth on culture. The organisms cultured were Staphylococcus epidemidis (six eyes), Streptococcus pneumoniae (five eyes), Sta. aureus (four eyes), Str. viridans (two eyes), Klebsiella oxytoca (one eye), Serratia marcescens (one eye), Moraxella sp (one eye), and Escherichia coli (one eye). The offending suture was removed in all cases, and the eyes were treated with topical fortified antibiotics (cefazolin and tobramycin). After treatment, 67% (12 of 18 eyes) had clear grafts, 17% (three of 18 eyes) were scarred, and 16% (three of 19 eyes) had failed grafts. Intensive topical steroid therapy was used when a subsequent graft rejection developed. Retained sutures following corneal transplants can result in sight-threatening infections and should be considered for removal as soon as the wound is well healed.

Significance of the lateral canthal tendon in craniofacial surgery.

Craniofacial approaches to the anterior skull base involve manipulation or removal of the supraorbital and frontozygomatic orbital margins. Necessarily, structures within the orbit are detached from the orbital margins. The lateral canthal tendon is attached to the inner aspect of the frontozygomatic process on the orbital osseous tubercle and is essential to the structural fixation of the lateral canthus as well as a check on the mobility of the lateral canthal angle of the eye itself. Our anatomic studies on the lateral canthal tendon as well as specific neurosurgical considerations in its mobilization are reviewed. The detachment of the lateral canthal tendon may result in blunting of the lateral canthal angle, a distraction of the eyelid away from the globe, or an asymmetric repositioning of the canthus as compared with the contralateral angle. It would appear that if the periosteum of the orbit is carefully dissected from the orbital rim and reapproximated following the procedure, the lateral canthal tendon insertion and function will not be disturbed unless the bony orbit margins are altered. In these instances, further ocular plastic surgery may be required.

Overacting oblique muscles in exotropia: a mechanical explanation.

Patients with exotropia often show apparent overaction of the inferior and superior oblique muscles. Are the oblique muscles contracted, are they truly overacting overacting, or does the eye flip up or down in adduction from the leash effect of a contracted lateral rectus muscle? Theoretically, if the mechanical limits of ocular rotations were circular or elliptical, rather than square or rectangular, we would expect a patient with exotropia to develop a vertical deviation in extreme gaze into the oblique quadrants, for the abducting eye would reach the mechanical limit, while the adducting eye would still be free to move up or down, giving the appearance of both inferior and superior oblique overaction. The circular or elliptical limits of ocular rotations were documented with tracings from slow-motion video recordings. Also, reduction of pseudo-overation of the obliques in both eyes following unilateral surgery for exotropia was observed in three patients. The strabismus surgeon should be aware of this possible mechanism for pseudo-overaction of the obliques and should avoid muscle surgery in this clinical setting.