Double use of corneal graft for Descemet stripping automated endothelial keratoplasty and coverage of glaucoma drainage device tube

Safety and Efficacy of Ahmed Valve on Intractable Glaucoma in Saudi Population

PURPOSE

The study aims to assess the efficacy and safety of Ahmed glaucoma valve implant in eyes with intractable glaucoma and to evaluate the risk factors for failure.

METHODS

A retrospective evaluation of 83 patients (117 eyes) with intractable glaucoma who underwent silicone Ahmed glaucoma valve implant was done in a tertiary care center in Riyadh, Saudi Arabia, between January 2014 and December 2016. Complete success was defined as intraocular pressure (IOP) ≤21 mmHg without medication after a minimum follow-up of 6 months.

RESULTS

Eighty-three patients (117 eyes) with intractable glaucoma were evaluated. After a mean follow-up duration of 20.8 ± 3.1 (12-24) months, the overall success rate was achieved in 104 eyes (88.9%). Thirty-six eyes (30.8%) had a complete success rate, whereas 68 eyes (58.1%) had a qualified success rate. Thirteen eyes (11.1%) failed to achieve controlled IOP. The postoperative probability to fail was found to be increasing with time from 0.9% (0.9) in the 1^st month to 11.1% (9.9) after 1 year. Complications included a hypertensive phase in 25 eyes (21.4%), encapsulation in 10 eyes (8.5%), hyphema in 7 eyes (6%), hypotony in 2 eyes (1.7%), and blood clots in the implanted tube in 2 eyes (1.7%). The presence of hyphema, scleral patch, and coronary heart diseases was found to increase the risk of failure after Ahmed valve implantation (P = 0.006, 0.040, and 0.014, respectively).

CONCLUSIONS

Ahmed glaucoma valve implant was safe and effective in treating cases of intractable glaucoma.

Partial thickness cornea tissue from small incision lenticule extraction: A novel patch graft in glaucoma drainage implant surgery

OBJECTIVE

The aim of the present study was to observe the feasibility and effect of cornea slice acquired from femtosecond laser surgery, small incision lenticule extraction (SMILE) as patch graft for the prevention of drainage tube exposure and to compare with the sclera.

METHODS

The research is a prospective comparative randomized study. Patients who received Ahmed glaucoma valve implantation surgery from August 2015 to January 2017 at the Xiamen Eye Center were randomly divided into 2 groups. Group A (corneal group) included 131 cases (135 eyes), receiving the 3 layers of allogeneic cornea slices as graft. Group B (scleral group) included 124 cases (127 eyes), using the sclera as allograft. The appearance, graft, conjunctiva melting, and tube exposure were the primary observation points.

RESULTS

After followed up for 6 to 20 months, a thinner appearance was seen in 3 eyes (2.2%) in the corneal graft group and 7 eyes (5.5%) in the scleral group. Conjunctiva melted and drainage tube exposed in 0 eyes (0%) in the corneal graft group and 2 eyes (1.6%) in the scleral group. One eye needed repair surgery. There was no statistical difference between the 2 groups (P > .05). After surgery, the intraocular pressure was reduced significantly in both groups (P < .05). The white sclera slice could be seen under the conjunctiva, thereby affecting the cosmetic appearance.

CONCLUSION

The cornea slice acquired from SMILE surgery can effectively prevent drainage tube exposure. Moreover, it is easy to acquire, safe, and cheaper, giving the patient a better cosmetic appearance.

Partial thickness corneal tissue as a patch graft material for prevention of glaucoma drainage device exposure

Background

To protect from erosion of the tube in glaucoma drainage device (GDD), the tube is covered by a biologic tissue which is roofed by the conjunctiva. Sclera, pericardium, dura mater and cornea are available as a patch graft. Drawbacks of some of these materials may include high cost and poor appearance. The purpose of this study is to report the long-term outcomes of partial thickness corneal grafts to cover the tube and prevent its exposure, in GDD surgeries.

Methods

This was a retrospective review of all patients who underwent Ahmed glaucoma valve implantation and had a minimum follow-up of 12 months. The tube was covered by a 300-micron partial thickness corneal graft taken either from a previous Descemet stripping endothelial keratoplasty procedure or cut from a whole corneal graft button unsuitable for keratoplasty.

Results

Forty-four patients (45 eyes, mean follow-up of 27.6 ± 11.4 months) were enrolled. The partial thickness corneal grafts maintained clarity throughout follow-up with satisfactory cosmetic results. Mild conjunctival retraction occurred in 4 eyes (8.9 %) between 1 and 12 months after the surgery. Corneal graft melting occurred in 3 (6.7 %) eyes. Tube exposure and additional surgery to re-patch or suture the conjunctiva over the tube was needed in 1 (2.2 %) eye. None of the patients had graft infection or immunologic rejection.

Conclusions

Partial thickness corneal grafts have favorable long-term outcome as a patch for GDD tubes with low rates of tube exposure and other complications.

The use of irradiated corneal patch grafts in pediatric Ahmed drainage implant surgery

PURPOSE

To describe the use of irradiated cornea for scleral reinforcement in Ahmed glaucoma valve drainage implant (AGV) devices in children.

METHODS

The medical records of patients <18 years of age who underwent AGV surgery with irradiated cornea as scleral reinforcement were reviewed retrospectively. The primary outcome measure was erosion of the drainage tube through the corneal patch graft. Secondary outcome measures included other major complications: persistent inflammation, wound dehiscence, transmission of infectious disease, endophthalmitis, and tube/plate self-explantation.

RESULTS

A total of 25 procedures (20 patients) met inclusion criteria. Average patient age was 70 months (range, 2 months to 17 years). Mean follow-up was 24.8 months (range, 6 months to 6.2 years). One tube experienced conjunctival exposure through two separate corneal grafts (2/25 cases [8%]), sequentially in the same eye. The first event occurred at month 3.5 after primary implantation of the tube shunt; the second erosion occurred following revision of the existing implant at month 1.5 postoperatively. There were 2 cases of auto-explantation, 2 cases of wound dehiscence, and 1 case of persistent inflammation. There were no cases of endophthalmitis or other infections.

CONCLUSIONS

To our knowledge, this is the first report describing the use of corneal patch grafts in children. Irradiated cornea improves cosmesis and enhances visualization of the tube. The risk of tube exposure was found to be low and comparable to other materials used as a patch graft.