1. Ayyala RS, Harman LE, Michelini-Norris B, et al. Comparison of different biomaterials for glaucoma drainage devices. Arch Ophthalmol. 1999;117:233-6.
Abstract: OBJECTIVES: To compare the inflammatory reaction associated with the insertion of silicone and polypropylene endplates and endplates made of a new biocompatible polymer, Vivathane, in the rabbit subconjunctival space. METHODS: Similar-sized endplates made of 3 different biomaterials were sutured to the sclera in the superotemporal quadrant of the rabbit eye. Thirty eyes of 15 albino New Zealand rabbits were randomly assigned to the 3 groups. Conjunctival vascular hyperemia was graded in a masked fashion among groups. At the end of 3 weeks, the enucleated eyes were examined histologically and using scanning electron microscopy. RESULTS: Polypropylene and Vivathane were associated with significantly more inflammation in clinical observations and based on histological grading. Silicone was associated with the least amount of inflammation. Three polypropylene and 1 Vivathane plate were extruded between the second and third week. CONCLUSIONS: Silicone is the most inert of the 3 materials tested. Inflammation associated with biomaterials may contribute to the failure of the glaucoma drainage devices. CLINICAL RELEVANCE: Bleb inflammation may be related to the biomaterial being used as the endplate. Endplates should be handled carefully during surgery to avoid creating rough spots
2. Ayyala RS, Cruz DA, Margo CE, et al. Cystoid macular edema associated with latanoprost in aphakic and pseudophakic eyes. Am J Ophthalmol. 1998;126:602-4.
Abstract: PURPOSE: To describe four patients who developed cystoid macular edema shortly after onset of treatment with latanoprost. METHOD: Retrospective review of medical records of patients with open-angle glaucoma who developed cystoid macular edema shortly after starting latanoprost. RESULTS: The use of topical latanoprost was temporally related to the development of cystoid macular edema in four patients (six eyes; two aphakic eyes and four pseudophakic eyes). Cystoid macular edema resolved in all patients after latanoprost was discontinued. CONCLUSIONS: Cystoid macular edema is a potential complication of latanoprost therapy. Further observations are needed to determine if the risk of cystoid macular edema is limited to or greatest in patients who are pseudophakic or aphakic
3. Ayyala RS, Zurakowski D, Smith JA, et al. A clinical study of the Ahmed glaucoma valve implant in advanced glaucoma. Ophthalmol. 1998;105:1968-76.
Abstract: OBJECTIVE: To assess clinical outcomes and establish the incidence and management of a hypertensive phase (HP) (defined as intraocular pressure [IOP] > 21 mmHg in the first 6 postoperative months) in patients with Ahmed glaucoma valve implant. DESIGN: Retrospective noncomparative case series. PARTICIPANTS: A total of 85 patients were included in the current study, including consecutive patients who had intractable glaucoma and underwent Ahmed valve implant insertion at the University Glaucoma Center, Tampa, Florida (DWR and WEL) and the Massachusetts Eye and Ear Infirmary (PAN) between January 1993 and June 1997. Only patients with a minimum of 6 months' follow-up were included. INTERVENTION: Ahmed glaucoma valve implant insertion to control intractable glaucoma was performed. MAIN OUTCOME MEASURES: Success was defined as IOP less than 22 mmHg and greater than 4 mmHg on the last two visits, a decrease of no more than two lines in the visual acuity and no additional surgical interventions to control IOP. RESULTS: The cumulative probability of success at 12 months was 77%. A total of 26 patients (30.6%) failed during the study period, and 70 patients (82%) exhibited HP. Hypertensive phase peaked at 1 month after the operation and stabilized at 6 months. There were 34 patients (48%) with HP who were controlled with additional medications: 14 (20%) with needling and 5-fluorouracil injections and 20 (28%) who needed secondary surgical intervention. There were 8 patients (9.4%) who exhibited hypotony (< 5 mmHg) on postoperative day 1 and 3 (3.5%) at 3 months. Visual acuity returned to baseline between 3 and 6 months after the operation. The major complications associated with the valve were hyphema in 14 cases (16.5%), suprachoroidal hemorrhage in 4 cases (4.7%), end-plate exposure in 10 cases (11.7%), tube exposure in 6 cases (7%), tube block in 4 cases (4.7%), loss of vision in 5 cases (5.8%), and corneal graft failure in 4 (30%) of 13 cases with clear grafts. CONCLUSIONS: The overall success rate is comparable to that of prior studies using different implants. The majority of the patients exhibit an HP that peaks at 1 month, with gradual stabilization over 6 months. One third of the patients needed secondary surgical intervention to control the HP. The incidence of postoperative hypotony and flat or shallow anterior chambers is very low after Ahmed glaucoma valve insertion
4. Ayyala RS, Pieroth L, Vinals AF, et al. Comparison of mitomycin C trabeculectomy, glaucoma drainage device implantation, and laser neodymium:YAG cyclophotocoagulation in the management of intractable glaucoma after penetrating keratoplasty. Ophthalmol. 1998;105:1550-6.
Abstract: PURPOSE: This study aimed to compare the surgical outcomes of mitomycin C trabeculectomy glaucoma drainage device (GDD) surgery and laser neodymium:YAG (Nd:YAG) cyclophotocoagulation (CPC) in the management of intractable glaucoma after penetrating keratoplasty (PKP) in a retrospective study. DESIGN: Interventional case series. PARTICIPANTS/METHODS: The medical charts of consecutive patients who had pre-existing glaucoma or who developed glaucoma after PKP and underwent a surgical procedure to control the glaucoma at the University Eye Associates of Boston University Medical Center, New England Eye Center, and Massachusetts Eye and Ear Infirmary between January 1991 and July 1995 were reviewed. Follow-up ranged from 6 months to 4 years after the glaucoma procedure. A total of 38 patients were included consisting of 17 patients who underwent mitomycin C, 10 patients who underwent GDD surgery, and 11 patients who had CPC. INTERVENTION: Mitomycin C trabeculectomy, GDDs, or Nd:YAG CPC to control glaucoma after PKP was performed, MAIN OUTCOME MEASURES: Graft status, postoperative intraocular pressure (IOP), and visual acuity were the main outcome measures. RESULTS: There were no differences among the three groups with respect to the follow-up time after the corneal graft operation (P = 0.15) or after the glaucoma operation (P = 0.98). At the final follow-up, the average decrease in the IOP was 17 mmHg (P < 0.001) after mitomycin C, 15 mmHg (P = 0.003) after GDD surgery, and 14.4 mmHg (P = 0.001) after CPC. There were no differences in the proportion of patients who developed postoperative IOP above 20 mmHg (P = 0.50) and in the proportion who developed hypotony (P = 0.10) among the three groups. Two grafts failed after mitomycin C and one failed after CPC. Among the three procedures, there were no differences in the proportion of patients who experienced either an improvement (P = 0.14) or a decrease (P = 0.22) in the visual acuity by more than one line after the glaucoma procedure. One patient each in the GDD group and the CPC group lost light perception after the procedure. The risk of graft failure was almost three times higher for each additional PKP (odds ratio = 2.80, P = 0.02). CONCLUSIONS: No differences were found among the three glaucoma procedures with respect to controlling IOP and graft failure. There was a trend for patients treated with CPC to have a higher incidence of graft failure, glaucoma failure, hypotony, and visual loss by more than one line, although this was not statistically significant. The number of PKPs was associated with graft failure, independent of the surgical procedure
5. Ayyala RS, Armstrong S. Corneal melting and scleromalacia perforans in a patient with pyoderma gangrenosum and acute myeloid leukemia. Ophthalmic Surgery & Lasers. 1998;29:328-31.
Abstract: Postoperative endophthalmitis may present in an atypical fashion (absent or minimal anterior chamber reaction) in the presence of underlying immunosuppressive disorder. The authors describe an apparently healthy 58-year-old man who displayed endophthalmitis with minimal anterior chamber reaction following penetrating keratoplasty for granular corneal dystrophy with underlying acute myeloid leukemia. Scleromalacia perforans in association with pyoderma gangrenosum subsequently developed, leading to ciliary staphyloma and corneal melting. Pyoderma gangrenosum is an uncommon, idiopathic skin disease that may also have ocular manifestations
6. Ayyala RS, Stevens SX, Grizzard WS, Fouraker BD. Recurrent endophthalmitis after cataract surgery with a scleral-tunnel incision. Cornea. 1998;17:233-5.
Abstract: PURPOSE: To present a case of recurrent postoperative endophthalmitis with a scleral-tunnel abscess and adjacent microbial keratitis. METHODS: A 76-year-old woman with microbial keratitis and recurrent endophthalmitis after cataract surgery was referred to a tertiary care center for further management. The medical chart of the patient was reviewed. RESULTS: The patient was seen on the eighth postoperative day with endophthalmitis that responded to medical treatment. Initial vitreous cultures were negative. The endophthalmitis recurred after the medical treatment was discontinued. She subsequently developed microbial keratitis at 1 o'clock adjacent to the limbus. Cultures from the site of corneal abscess and vitreous grew coagulase-negative Staphylococcus. Gonioscopy revealed the presence of a scleral abscess, which responded to subconjunctival injection of vancomycin and an intense and prolonged course of topical antibiotics. CONCLUSION: A scleral abscess should be suspected in a patient with endophthalmitis or microbial keratitis or both after a scleral-tunnel incision for cataract surgery
7. Ayyala RS, Bellows AR, Thomas JV, Hutchinson BT. Bleb infections: clinically different courses of "blebitis" and endophthalmitis. J Ophthalmol Nurs Tech. 1997;16:292-300.
Abstract: 1. Researchers have recently introduced the term "blebitis" to describe a limited form of bleb-related infection (with infection and inflammation limited to the bleb and the peri-bleb area, with or without anterior chamber involvement) in contrast to the more classic form of endophthalmitis. 2. Bleb-related endophthalmitis is the virulent form of bleb-related infection in which patients present with rapidly worsening visual acuity, redness, and pain with diffuse conjunctival congestion, opalescent blebs (with or without epithelial defects) with intense fibrin and/or hypopyon in the anterior chamber, and florid vitritis. 3. Blebitis and bleb-related endophthalmitis are two distinct bleb-related infections, each with different presentations, prognoses, and outcomes. It is important that clinicians recognize this and treat patients accordingly
8. Ayyala RS, Urban RCJ, Krishnamurthy MS, Mendelblatt DJ. Corneal blood staining following autologous blood injection for hypotony maculopathy. Ophthalmic Surgery & Lasers. 1997;28:866-8.
Abstract: Hypotony is a common complication following trabeculectomy in which antimetabolites are used. Autologous blood injection is an accepted form of treatment for hypotony that occurs secondary to overfiltration; however, injection into the filtering bleb has been associated with a rise in intraocular pressure for some patients with chronic postoperative hypotony. The authors describe a patient in whom corneal blood staining with raised intraocular pressure and loss of vision occurred as a result of autologous blood injection
9. Ayyala RS, Bellows AR, Thomas JV, Hutchinson BT. Bleb infections: clinically different courses of "blebitis" and endophthalmitis. [Review] [24 refs]. Ophthalmic Surgery & Lasers. 1997;28:452-60.
Abstract: BACKGROUND AND OBJECTIVES: To assess the differences in history, clinical course, and response between five cases of blebitis and three cases of endophthalmitis following mitomycin trabeculectomy. PATIENTS AND METHODS: The authors conducted a retrospective review of eight consecutive cases of bleb-related infection following successful mitomycin trabeculectomy. RESULTS: All patients with blebitis responded to treatment with return of visual acuity and intraocular pressure to preinfection levels. In the three cases of endophthalmitis, one patient underwent enucleation, one had a final visual acuity of counting fingers, and the third had a visual acuity of 20/60. CONCLUSIONS: Blebitis, a limited form of bleb-related infection with thin, cystic, leaky blebs, responds to intensive topical antibiotic treatment, returning visual acuity and IOP to preinfection levels. Bleb-related endophthalmitis causes a more virulent form of bleb-related infection that involves thin- or thick-walled blebs, with or without leakage, and poor visual prognosis despite immediate intensive topical, systemic, and intravitreal antibiotic administration combined with core vitrectomy. [References: 24]
10. Ayyala RS, O'Brien CO, Grierson I, Maltby P. Transscleral flow of aqueous humor: an in vitro experiment. Ophthalmic Surgery & Lasers. 1996;27:66-9.
Abstract: BACKGROUND AND OBJECTIVE: The minimal scleral flap thickness to ensure transscleral flow following a trabeculectomy has never been determined. The present study was designed to determine, in vitro, the critical scleral flap thickness that allows transscleral flow. MATERIALS AND METHODS: The apparatus consisted of two horizontal glass chambers (A and B) connected to each other by a customized scleral disc holder. High-pressure chamber A (at 25 mm Hg) was filled with sodium pertechnetate (99mTc) labeled normal saline and low-pressure chamber B (at 5 mm Hg) with normal saline. Transscleral flow of labeled normal saline from high-pressure chamber A via varying thickness scleral discs to low-pressure chamber B was observed over 16 hours using a gamma camera. Computer analysis was performed on the obtained images. RESULTS: Transscleral flow of labeled saline was observed only with scleral discs 0.5 mm thick or less. CONCLUSIONS: If the findings hold true for the in vivo situation, aqueous humor may reach the subconjunctival space following trabeculectomy via the transscleral route, provided scleral flap thickness is less than 0.5 mm. In addition, normal uveoscleral aqueous outflow may occur across sclera less than 0.5 mm thick, e.g., posterior to extraocular muscle insertions