Ronald N. Gaster

Comparison of Penetrating Keratoplasty Performed with a Femtosecond Laser Zig-Zag Incision versus Conventional Blade Trephination

PURPOSE To evaluate visual outcomes and astigmatism in patients who underwent penetrating keratoplasty (PK) with 2 different incision techniques. DESIGN Retrospective comparison of a consecutive surgical series. PARTICIPANTS Fifty-seven consecutive patients who underwent PK at the University of California, Irvine, academic referral practice. METHODS A comparison of 49 eyes of 43 patients that underwent femtosecond laser zig-zag incision pattern PK versus 17 eyes of 14 patients that underwent conventional Barron suction trephination PK performed contemporaneously. All PKs were closed with an identical, 24-bite running nylon suture technique. MAIN OUTCOME MEASURES Topographically determined astigmatism, best spectacle-corrected visual acuity (BSCVA), and recovery of full visual potential. RESULTS The postoperative follow-up ranged from 1 to 12 months. There was a significant difference in average astigmatism between the groups at postoperative month 1 (P = 0.013) and 3 (P = 0.018). By month 3, the average astigmatism was 3 diopters (D) in the zig-zag group and 4.46 D in the conventional group. Of the patients with normal macular and optic nerve function (n(ZZ) = 32; n(con) = 14), a significant difference in BSCVA was seen at month 1 (P = 0.0003) and month 3 (P = 0.006) with 81% of the zig-zag group versus 45% of the conventional group achieving BSCVA of > or =20/40 by month 3 (P = 0.03). CONCLUSIONS The femtosecond laser generated zig-zag-shaped incision results in a more rapid recovery of BSCVA and induces less astigmatism compared with conventional blade trephination PK. FINANCIAL DISCLOSURE(S) Proprietary commercial disclosure may be found after the references.

Quantitative assessment of UVA-riboflavin corneal cross-linking using nonlinear optical microscopy.

PURPOSE Corneal collagen cross-linking (CXL) by the use of riboflavin and ultraviolet-A light (UVA) is a promising and novel treatment for keratoconus and other ectatic disorders. Since CXL results in enhanced corneal stiffness, this study tested the hypothesis that CXL-induced stiffening would be proportional to the collagen autofluorescence intensity measured with nonlinear optical (NLO) microscopy. METHODS Rabbit eyes (n = 50) were separated into five groups including: (1) epithelium intact; (2) epithelium removed; (3) epithelium removed and soaked in riboflavin, (4) epithelium removed and soaked in riboflavin, with 15 minutes of UVA exposure; and (5) epithelium removed and soaked in riboflavin, with 30 minutes of UVA exposure. Corneal stiffness was quantified by measuring the force required to displace the cornea 500 μm. Corneas were then fixed in paraformaldehyde and sectioned, and the collagen autofluorescence over the 400- to 450-nm spectrum was recorded. RESULTS There was no significant difference in corneal stiffness among the three control groups. Corneal stiffness was significantly and dose dependently increased after UVA (P < 0.0005). Autofluorescence was detected only within the anterior stroma of the UVA-treated groups, with no significant difference in the depth of autofluorescence between different UVA exposure levels. The signal intensity was also significantly increased with longer UVA exposure (P < 0.001). Comparing corneal stiffness with autofluorescence intensity revealed a significant correlation between these values (R(2) = 0.654; P < 0.0001). CONCLUSIONS The results of this study indicate a significant correlation between corneal stiffening and the intensity of collagen autofluorescence after CXL. This finding suggests that the efficacy of CXL in patients could be monitored by assessing collagen autofluorescence.

Unusual Superficial Confluent Form of Granular Corneal Dystrophy

A 53-year-old Japanese woman had corneal opacification due to granular dystrophy (GCD) since childhood. Clinically, unusual bilateral confluent dense granular opacities with a peripheral rim of clear cornea were observed. Her mother and daughter have a milder form of GCD, with circumscribed opacities separated by clear stroma. Light and electron microscopy of the patients corneal button showed that the opacities involved the corneal epithelium as well as the stroma.

Organic tissue glue in the closure of cataract incisions in rabbit eyes

ABSTRACT We performed 7 mm scleral pocket cataract incisions in both eyes of ten rabbits. One eye of each rabbit was closed with one interrupted 10‐0 nylon suture and organic tissue glue (Tisseel®) and the other was closed with a conventional shoelace running 10‐0 nylon suture. The eyes were examined clinically and histopathologically at various postoperative intervals. No difference in wound integrity was found between the two closures, but slightly more inflammation occurred in the eyes closed with glue than in those closed with sutures alone. Organic tissue glue may become an alternative method to suture closure of scleral pocket cataract incisions.

Organic tissue glue in the closure of cataract incisions

ABSTRACT We report our initial studies with a new organic tissue glue (Tisseel) in the closure of cataract incisions made in fresh cadaver eyes. We made two types of cataract incisions, posterior beveled and scleral pocket, and closed them with nylon sutures, glue, or a combination of both. The 11‐mm posterior‐beveled incision required eight nylon sutures, with or without glue, to maintain wound integrity at high intraocular pressures. We found the 7‐mm and 11‐mm pocket‐type incisions to be essentially self‐sealing and to leak only when posterior scleral lip pressure was applied. Once glue was added, even high posterior pressure did not disrupt the wound. This glue may thus present an alternative to suture closure of scleral pocket cataract incisions.

A comparison of anterior chamber and posterior chamber intraocular lenses after vitreous presentation during cataract surgery: the Department of Veterans Affairs Cooperative Cataract Study

PURPOSE To compare the efficacy and safety of anterior chamber (AC) intraocular lenses (IOLs) and posterior chamber (PC) IOLs implanted after vitreous presentation during extracapsular cataract extraction (ECCE). DESIGN The study was a prospective, long-term, randomized clinical trial conducted at 19 Department of Veterans Affairs medical centers across the United States. METHODS There were 438 eyes (438 patients) that met preliminary eligibility criteria, suffered vitreous presentation during ECCE (phacoemulsification or classical extracapsular technique), and had sufficient capsular support for a PC IOL without sutures after anterior vitrectomy randomized to either a PC IOL (230 patients) or an AC IOL (208 patients). Patients were examined at 3, 6, and 12 months post-surgery and yearly thereafter. Minimum follow-up was 1 year. The primary outcome measure of best-corrected visual acuity at 1 year was obtained by a masked certified examiner. RESULTS More PC IOL patients (91%) achieved visual acuity of 20/40 or better at 1 year than AC IOL patients (79%), a highly significant difference (P =.003). There was no significant difference between the two groups for patients rating of vision or adverse events. Over 84% of the PC IOL patients and over 77% of the AC IOL patients rated their vision as good or better at 1 year as opposed to only 7% giving such ratings before surgery. For at least one rating period during the first year, 13.2% of the combined study patients had cystoid macular edema, 8.5% had posterior capsule opacification, 5.7% had glaucoma, and 3.7% had retinal detachment. CONCLUSION In the presence of sufficient capsular support, a PC IOL should be implanted after vitreous presentation during ECCE.

Comparison of corneal surface higher-order aberrations after endothelial keratoplasty, femtosecond laser-assisted keratoplasty, and conventional penetrating keratoplasty.

Purpose: To evaluate and compare corneal higher-order aberrations (HOAs) after Descemet stripping automated endothelial keratoplasty (DSAEK), femtosecond laser–assisted penetrating keratoplasty (FLAK), and conventional penetrating keratoplasty (PKP). Methods: A retrospective comparison of consecutive surgical series of 67 eyes of 59 patients between 1.5 and 19 months after corneal transplant surgery (22, 34, and 11 corneas underwent DSAEK, FLAK, and PKP, respectively, by a single surgeon). The main outcome measures were anterior and posterior corneal surface HOAs (Zernike polynomials, third to eighth order) determined with Scheimpflug photography at 4.0- and 6.0-mm optical zones and best spectacle-corrected visual acuity (BSCVA) (logarithm of the minimum angle of resolution equivalents). Results: DSAEK had fewer total anterior HOAs compared with FLAK [P = 5.27 × 10−5 (4.0 mm) and P = 1.02 × 10−5 (6.0 mm)] and PKP [P = 1.82 × 10−4 (4.0 mm) and P = 1.56 × 10−4 (6.0 mm)] but greater total posterior HOAs than FLAK [P = 0.001 (4.0 mm) and P = 0.007 (6.0 mm)] and PKP [at 4.0-mm optical zone (P = 0.047)]. FLAK had fewer total anterior and posterior HOAs than PKP, but differences were not statistically significant. DSAEK grafts exhibited statistically significantly greater posterior HOAs than either type of PKP. The magnitude of anterior and posterior HOAs weakly correlated with BSCVA. Conclusions: DSAEK induces fewer anterior surface HOAs but greater posterior surface HOAs than FLAK or PKP. Differences between FLAK and PKP are not statistically significant. Anterior and posterior HOAs correlate weakly with poorer visual outcome and likely contribute to decreased BSCVA after keratoplasty.

Results of Toric Intraocular Lenses for Post-Penetrating Keratoplasty Astigmatism

PURPOSE Evaluate the usefulness of toric intraocular lens (IOL) implantation during cataract surgery in patients after penetrating keratoplasty (PKP). DESIGN Retrospective case review. PARTICIPANTS A total of 21 eyes of 16 patients with prior PKP and moderate to high regular astigmatism after full suture removal underwent phacoemulsification and implantation of a single-piece acrylic toric IOL (SN6AT series; Alcon, Fort Worth, TX). METHODS Patients underwent comprehensive examinations at standard intervals, including visual acuity, manifest refraction, and corneal topography. MAIN OUTCOME MEASURES Uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) expressed as the logarithm of the minimum angle of resolution (logMAR) and manifest refraction astigmatism. RESULTS From preoperatively to the last visit (mean, 14.7 ± standard deviation 12.8 months), the 21 eyes had significant improvement in UDVA (logMAR, 0.90 ± 0.48 to 0.23 ± 0.25; P = 0.0001) and CDVA (logMAR, 0.31 ± 0.14 to 0.08 ± 0.13; P = 0.0001). A total of 14 of 21 eyes (67%) and 17 of 21 eyes (81%) had UDVA and CDVA of ≥ 20/30, respectively. Preoperative topographic astigmatism was 4.57 ± 2.05 diopters (D). Postoperative manifest refraction astigmatism was 1.58 ± 1.25 D overall, but lower (0.75 ± 0.54 D) in the T7-T9 subgroup (excluding 1 outlier whose corneal astigmatism doubled after surgery) than in the T4-T6 subgroup (1.88 ± 1.28 D; P = 0.013). A total of 16 of all 21 eyes (76.2%) and 8 of 9 eyes (89%) in the T7-T9 subgroup were within 1 D of postoperative manifest astigmatism as predicted or better. CONCLUSIONS Toric IOLs placed during cataract surgery after PKP and full suture removal can reduce manifest refraction cylinder to predictably low levels with corresponding improvement in UDVA and CDVA in patients with moderate to high regular preoperative topographic astigmatism.

Pseudophakic corneal edema: A review of mechanisms and treatments.

Purpose: To review the pathological mechanisms and treatments for pseudophakic corneal edema (PCE), one of the most common indications for penetrating keratoplasty. Methods: The literature was examined for the molecular biology associated with PCE and for the surgical and medical treatments for this disorder. Results: The incidence of PCE has recently been decreasing because of improved surgical instrumentation, including improvements in intraocular lens designs that cause less trauma to the corneal endothelium. Extracellular matrix and growth factor abnormalities occur in PCE corneas and recently, the role of aquaporins, which are involved in the regulation of fluid movement across cells, has been investigated. Conclusions: Although newer treatment options have been suggested, penetrating keratoplasty still remains the most definitive treatment and has the highest success rate.

Penetrating keratoplasty in active Acanthamoeba keratitis.

Purpose: To report the results of penetrating keratoplasty (PK) in active Acanthamoeba keratitis (AK). Methods: Nine patients with deep stromal infiltrates because of AK were treated with intensive antiamoebic medical therapy followed by PK during the acute infectious phase because of poor clinical response or poor compliance. Antiamoebic therapy was tapered after PK. Results: Visual acuity ranged from 20/15 to 20/50 after an average of 17 months after PK with no signs of recurrences. Patients had rapid resolution of symptoms. Conclusion: PK is a viable option for active AK not responding to maximum medical treatment.