Clinical Factors Impacting Outcomes From Failed Trabeculectomy Leading to Glaucoma Drainage Device Implantation and Subsequent Penetrating Keratoplasty

PRCIS

We evaluated the factors that impacted time from glaucoma drainage implant (GDI) surgery to penetrating keratoplasty (PK) in eyes with previously clear corneas (ie, GDI-first sequence), and that specifically underwent a trabeculectomy before GDI surgery for intraocular pressure (IOP) control.

PURPOSE

To describe through an event-triggered data collection method the clinical course and the long-term outcomes of 2 procedures that are commonly performed sequentially in complex clinical situations: GDI surgery and PK. The study investigates the clinical factors associated with the progression to PK and determines the GDI success rate and graft survival.

METHODS

A single, tertiary-care center retrospective interventional cases series including patients with a sequential history of trabeculectomy, GDI surgery, and PK from 1999 to 2009. Outcome measures included IOP, visual acuity, graft failure, GDI failure, and time from GDI to PK.

RESULTS

Of the eyes, 56% had primary open angle glaucoma. The time from the last trabeculectomy to GDI was 66.5 ± 66.7 months. Of the eyes, 84% received a Baerveldt GDI. Time from GDI to PK was 36.4 ± 28.4 months. IOP at the time of PK was between 5 mm Hg and 21 mm Hg in 90% of eyes. At the last follow-up, 48% of grafts were clear. At 5 years post-PK, 33% of corneal grafts remained clear, whereas 81% of tubes remained functional.

CONCLUSIONS

Nearly half of the corneal grafts are clear at the last long-term follow-up. Graft failure occurs at a higher rate than tube failure suggesting that IOP control is only one and possibly not the most important factor in graft survival in eyes with prior glaucoma surgery.

Dosimetric effects of bolus and lens shielding in treating ocular lymphomas with low-energy electrons

Radiation therapy is an effective treatment for primary orbital lymphomas. Lens shielding with electrons can reduce the risk of high-grade cataracts in patients undergoing treatment for superficial tumors. This work evaluates the dosimetric effects of a suspended eye shield, placement of bolus, and varying electron energies. Film (GafChromic EBT3) dosimetry and relative output factors were measured for 6, 8, and 10 MeV electron energies. A customized 5-cm diameter circle electron orbital cutout was constructed for a 6 × 6-cm applicator with a suspended lens shield (8-mm diameter Cerrobend cylinder, 2.2-cm length). Point doses were measured using a scanning electron diode in a solid water phantom at depths representative of the anterior and posterior lens. Depth dose profiles were compared for 0-mm, 3-mm, and 5-mm bolus thicknesses. At 5 mm (the approximate distance of the anterior lens from the surface of the cornea), the percent depth dose under the suspended lens shield was reduced to 15%, 15%, and 14% for electron energies 6, 8, and 10 MeV, respectively. Applying bolus reduced the benefit of lens shielding by increasing the estimated doses under the block to 27% for 3-mm and 44% for 5-mm bolus for a 6 MeV incident electron beam. This effect is minimized with 8 MeV electron beams where the corresponding values were 15.5% and 18% for 3-mm and 5-mm bolus. Introduction of a 7-mm hole in 5-mm bolus to stabilize eye motion during treatment altered lens doses by about 1%. Careful selection of electron energy and consideration of bolus effects are needed to account for electron scatter under a lens shield.

In vivo effects of femtosecond laser-assisted keratoplasty

IMPORTANCE

The femtosecond laser is reported to cut lamellar surfaces with varying degrees of smoothness depending on the depth of the cut, with deeper cuts leaving less smooth surfaces. We attempted to evaluate the smoothness of the deeper lamellar surface as cut by the femtosecond laser after allowing 3 months of in vivo healing.

OBSERVATIONS

Two patients underwent penetrating keratoplasty 3 months after inadequate visual rehabilitation following femtosecond laser-assisted sutureless anterior lamellar keratoplasty for the treatment of anterior stromal scars. In vivo confocal microscopy that was performed before penetrating keratoplasty demonstrated an acellular zone with a hyperintense signal consistent with a mild interface opacification. Light microscopy in one patient demonstrated scarring limited primarily to the posterior stroma; in the other patient, the interface was smooth with mild scarring of the anterior lamellae. When studied with electron microscopy, the cut surfaces revealed a smooth to very mild stuccolike appearance that was smoother than anticipated.

CONCLUSIONS AND RELEVANCE

After 3 months of in vivo healing, the lamellar interface produced by the femtosecond laser, as imaged by electron microscopy, appeared to be nearly smooth with minimal roughness to the cut surfaces. We attribute this to the effects of in vivo healing and remodeling.

Free floating cyst in anterior chamber after cataract surgery

We describe a free-floating cyst in the anterior chamber after cataract surgery in a 73-year-old woman who underwent uneventful phacoemulsification in her right eye (OD). The best-corrected visual acuity one week after surgery was 20/20 OD; however, six weeks later, she noted the onset of intermittent "shadows" in this eye whenever she changed head position. Slit lamp examination showed a round, free-floating, clear cyst (3-4 mm in diameter) that traversed the central visual axis during eye movement. The cyst was removed through a limbal incision, by expressing it gently out of the eye with viscoelastic injection into the anterior chamber. On pathological examination the inner wall of the cyst was lined with non-keratinized squamous epithelium, typical of ocular surface cells.

The effect of the timing of scleral flap suture release on the safety and long-term success of phacotrabeculectomy

PURPOSE

To investigate the effect of the timing of the scleral flap suture release on the safety and long-term success of phacotrabeculectomy.

DESIGN

Retrospective, nonrandomized chart review.

METHODS

We studied 173 eyes of 173 consecutive patients who underwent primary phacotrabeculectomy, with or without intraoperative mitomycin-C, and subsequent scleral flap suture release.

RESULTS

Early suture release (<3 weeks) had a lower long-term success rate than late suture release (>3 weeks), with an average follow-up period of 44.8 months. Patients who used mitomycin-C had statistically later suture release than did patients without mitomycin-C. There were nine cases of hypotony, for which independent risk factors were early suture release and the use of mitomycin-C.

CONCLUSIONS

Greater long-term success with minimal complications was achieved when scleral flap suture release was performed three weeks after phacotrabeculectomy. Suture release within three weeks after surgery was associated with an increased risk of filtration failure and a higher risk of postoperative complications.