Alja Crnej

Rotational stability of a single-piece toric acrylic intraocular lens

PURPOSE: To assess the rotational stability of a single‐piece toric hydrophobic acrylic intraocular lens (IOL) during the first 6 postoperative months. SETTING: Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom. DESIGN: Prospective case series. METHOD: Eyes with age‐related cataract and corneal astigmatism (1.00 to 3.00 D diopter [D]) were measured by partial coherence interferometry (IOLMaster). Preoperatively, the horizontal axis was marked. Surgical technique included a standardized temporal clear corneal incision, phacoemulsification, and in‐the‐bag implantation of a toric IOL (AcrySof SN60TT). Rotational stability of the IOL was assessed using retroillumination photographs postoperatively at 1 hour and at 1 and 6 months. Uncorrected (UDVA) and corrected distance visual acuities, residual refractive error, and keratometric and refractive cylinders were measured. RESULTS: The study enrolled 30 eyes (30 patients). The mean absolute IOL rotation was 2.44 degrees ± 1.84 (SD) at 1 month and 2.66 ± 1.99 degrees at 6 months. The photographic technique had high reproducibility of axis measurement, with consecutive measurements varying by less than 2.0 degrees. The mean UDVA was 0.16 logMAR (range 0.42 to −0.18 logMAR) at 1 month and 0.20 logMAR (range 0.60 to −0.20 logMAR) at 6 months. The residual refractive cylinder by autorefraction was −0.84 D (range −2.00 to 0.00 D) and −0.80 D (range −1.75 to 0.00 D), respectively. CONCLUSIONS: The acrylic toric IOL was rotationally stable within the first 6 months postoperatively. The photographic and axis analysis method to evaluate stability had high reproducibility and detected small changes in rotation. Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.

Glaucoma progression and role of glaucoma surgery in patients with Boston keratoprosthesis.

Purpose: The aim of this study was to evaluate glaucoma onset and progression after implantation of Boston Keratoprostheses (B-KPro) and the role of glaucoma surgery. Methods: Records of patients with B-KPro implantation during 2004 to 2009 were reviewed. Parameters relevant to B-KPro surgery and glaucoma status were recorded. The data were analyzed in 5 groups based on the preoperative diagnosis. Results: One hundred six eyes of 87 patients were included, and the average age was 54 ± 6.7 years. Forty-six percent were female. Eighteen eyes had a B-KPro with a titanium back plate, and the others had a poly(methyl methacrylate) back plate. Thirty-three eyes were pseudophakic, and the rest were left aphakic. The follow-up time was 3.3 ± 1.0 years. Indications for implantation included past infection, congenital glaucoma, trauma, autoimmune diseases, aniridia, burns, and others. Sixty-six percent of the eyes had glaucoma preoperatively, and 26% developed de novo glaucoma afterward. The mean intraocular pressure (by finger palpation) was 16.5 ± 5.7 mm Hg. Reliable visual field tests were only available in 59% of the eyes; hence, the cup-to-disc ratio of the optic nerve head was used as the main outcome measure. In B-KPro–implanted eyes with glaucoma, 65% had undergone glaucoma surgery at some point, and 30% did not show progression. Thirty-one percent of the total cohort had disc pallor with a cup-to-disc ratio of <0.8. Conclusions: Glaucoma in B-KPro remains a challenge, despite aggressive attempts to slow down its progression. Patients with glaucoma before B-KPro implantation should be considered for glaucoma surgery before or simultaneously with B-KPro implantation. The high number of eyes with disc pallor suggests that additional mechanisms other than elevated intraocular pressure may play a role in optic neuropathy.

Correction of moderate corneal astigmatism during cataract surgery: Toric intraocular lens versus peripheral corneal relaxing incisions

Purpose To compare the astigmatism‐reducing effect of a toric intraocular lens (IOL) and peripheral corneal relaxing incisions (PCRIs). Setting Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom. Design Prospective masked bilateral randomized study. Methods Cataract patients with a preoperative corneal astigmatism of 1.0 to 2.5 diopters (D) were included. All patients received a toric IOL in 1 eye and a nontoric IOL plus a PCRI in the other eye. Postoperative follow‐up was at 1 hour, 1 month, and 6 months. The uncorrected distance visual acuity, corrected distance visual acuity, autorefraction (Topcon RM‐8800), and subjective refraction were recorded. The IOL axis was assessed using retroillumination photographs. Results The study enrolled 60 eyes of 30 patients. The mean astigmatism vector reduction was 1.74 D ± 0.64 (SD) in the toric IOL group and 1.27 ± 0.76 D in the PCRI group; the difference was statistically significant (P=.042). The mean absolute rotation of the toric IOL was 2.5 ± 1.8 degrees (maximum 6.3 degrees) in the first 6 postoperative months. Astigmatism increased in the PCRI group between the 1‐month and 6‐month follow‐up (mean 0.38 ± 0.27 D; maximum 1.00 D) (P<.001). Conclusion Toric IOLs and PCRIs both reduced astigmatism; however, toric IOLs reduced astigmatism to a higher extent and they were more predictable. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

Effect of fluorescein dye staining of the tear film on Scheimpflug measurements of central corneal thickness.

Purpose: To assess whether fluorescein dye in the tear film results in a clinically relevant change in central corneal thickness (CCT), as measured with Scheimpflug imaging (Pentacam HR; Oculus, Wetzlar, Germany). The study was conducted at Moorfields Eye Hospital NHS Foundation Trust. Methods: In this prospective, randomized, controlled, single-center study on healthy volunteers, CCT was measured using rotating Scheimpflug imaging and partial coherence interferometry technique. After 3 baseline measurements of both eyes, a drop of 0.25% fluorescein with 0.5% proxymetacaine hydrochloride dye, as used for measuring intraocular pressure with applanation Goldmann tonometry, was instilled in the first eye and measurements were repeated after 1 minute and 5, 10, 20, 40, and 60 minutes. A fluorescein drop was then instilled in the second eye, and 1 measurement was performed after 1 minute. Immediately afterwards, the second eye was rinsed with 2 ml of balanced saline solution and the CCT measurement was repeated. On a different day, a Schirmer II test was performed. Results: Thirty eyes of 15 volunteers were included in this study. The average CCT measured with Scheimpflug imaging was 539.1 μm (SD, 32.2 μm), and after instilling fluorescein, CCT values increased by 46.6 μm (SD, 11.4 μm; P < 0.01, paired t test). In 10 of 15 subjects, the fluorescein layer was still present 40 minutes after instilling the drop. Rinsing the eye decreased the fluorescein layer by 49.6% and a value of 24.8 μm (SD, 16.8 μm). Conclusions: Because CCT measurements are critical for corneal refractive surgery, Scheimpflug imaging should not be performed after use of fluorescein dye for staining of the corneal epithelium or for applanation tonometry.

Idiopathic vitritis in the setting of Boston keratoprosthesis.

Purpose: The aim of this study was to revisit the clinical paradigm attributed to Boston keratoprosthesis recipients presenting with idiopathic vitreous inflammation. Methods: A retrospective chart review was performed of keratoprosthesis recipients at Massachusetts Eye and Ear Infirmary, from January 2000 to August 2013, for demographic data, indication(s) for surgery, timing and presentation of vitreous inflammation, and best-corrected visual acuity at baseline, on presentation, and after resolution of vitritis. Results: Twenty-three (23 eyes) of 346 patients developed idiopathic vitreous inflammation after keratoprosthesis implantation. Six of 23 patients presented with signs and symptoms similar to infectious endophthalmitis but were culture negative. The proportion of patients who fit the previous paradigm of sudden painless loss of vision without external signs of infection (“sterile vitritis”) at their first presentation with vitritis was only 4 of 23. Vision decline was variable (median, 9 lines on Snellen chart; range, 0–24), as was time to recovery of best vision (median, 8.9 weeks; range, 0.9–36.7). Nine eyes had repeat bouts (43 episodes in 23 patients). Ten of 43 episodes did not recover to baseline vision. Seventeen of 23 eyes with idiopathic vitritis after keratoprosthesis later developed other complications. Conclusions: The current paradigm for idiopathic vitritis after keratoprosthesis implantation includes sudden painless loss of vision with full recovery of vision on treatment with periocular corticosteroids. However, idiopathic vitritis after keratoprosthesis can also mimic infectious endophthalmitis with pain and external signs of inflammation. Visual loss can be gradual. Vision may not recover to baseline despite treatment. Vitritis may be a part of a common pathway of chronic inflammation after keratoprosthesis.

Corneal Inflammation After Miniature Keratoprosthesis Implantation

PURPOSE To compare corneal inflammation after syngeneic and allogeneic penetrating keratoplasty (PK) with miniature Keratoprosthesis (m-KPro) implantation in mice. METHODS BALB/C (syngeneic) or C57BL/6 (allogeneic) corneas were transplanted onto BALB/C host beds as part of PK or m-KPro implantation. Corneal inflammation was assessed by determining the frequencies of CD45(+) leukocytes, CD4(+) T cells, CD11b(+) cells, and Gr-1(+) granulocytes/monocytes by flow cytometry at 2, 4, and 8 weeks post transplantation. In addition, expression levels of the proinflammatory cytokines TNF-α and IL-1β were analyzed using real-time qPCR at 8 weeks post transplantation. RESULTS Cell frequencies in the syngeneic (syn) and allogeneic (allo) m-KPro groups were higher compared with the syngeneic and allogeneic PK groups, respectively, at all time points. However, after week 4, frequencies of all analyzed immune cells were higher in the alloPK group as compared with synKPro group. At 8 weeks, the expression of TNF-α was higher in synKPro, alloPK, and alloKPro groups compared with the naïve and synPK groups. The expression of IL-1β was significantly higher in both KPro groups as compared with PK groups. CONCLUSIONS Although the m-KPro device augments the inflammatory response in the cornea after its implantation, allogenicity (of the carrier tissue) is also a significant contributor to corneal inflammation. These data suggest that using syngeneic or decellularized corneal tissue as a Boston-KPro carrier could reduce the postoperative inflammation response.

Infliximab after Boston Keratoprosthesis in Stevens-Johnson Syndrome: An Update.

ABSTRACT Purpose: To report our experience using intravenous infliximab for the treatment of tissue melt after Boston keratoprosthesis (B-KPro) types I and II in patients with autoimmune disease. Methods: Case series. Results: We identified four patients who were treated with intravenous infliximab in the context of tissue melt after B-KPro. Stevens–Johnson syndrome-associated corneal blindness was the primary surgical indication for B-KPro implantation in all patients. Two patients received a B-KPro type I and two patients received a B-KPro type II. The patients received intravenous infliximab for skin retraction around B-KPro type II, melting of the carrier graft or leak. Treatment resulted in a dramatic decrease in inflammation and, in some cases, arrest of the melting process. Cost and patient adherence were limiting factors to pursuing infliximab therapy. In addition, one patient developed infusion reactions. Conclusions: Intravenous infliximab may be considered as globe- and sight-saving therapy for tissue melt after B-KPro.

Capsular bag performance of a hydrophobic acrylic 1-piece intraocular lens.

Purpose To compare parameters after 1‐piece and 3‐piece intraocular lens (IOL) implantation. Setting Moorfields West End Clinic, London, United Kingdom, and Hanusch Hospital, Vienna, Austria. Design Prospective randomized controlled trial. Methods Each eye of patients having bilateral surgery for age‐related cataract was randomized to have implantation of a 1‐piece IOL (Tecnis ZCB00) or a 3‐piece IOL (Tecnis ZA9003). Changes in visual acuity, refraction, and anterior chamber depth (ACD) were evaluated during a 2‐year follow‐up. Intraocular lens tilt and decentration were evaluated using a Purkinje meter. Regeneratory posterior capsule opacification (PCO) was analyzed using retroillumination photographs in Automated Quantification of After‐Cataract image‐analysis software. Results This study comprised 100 eyes of 50 patients. No statistically significant differences were found in IOL tilt or decentration between groups (P≥.06). Minimal but statistically significant changes were observed in the vertical tilt component 12 months postoperatively in the 3‐piece IOL group (P<.01). The tilt and decentration components did not correlate with changes in sphere or the regeneratory PCO score (r = 0.38, P≥.06). The ACD decreased significantly between 1 day and 1 month postoperatively in both groups (P<.01), with no significant changes afterward (P≥.22). The anterior chamber was significantly deeper in the 1‐piece group at all follow‐up visits (P<.01). Conclusions Both the 1‐piece IOL and the 3‐piece IOL showed excellent positional stability in the capsular bag, resulting in good clinical outcomes. Regeneratory PCO levels were low and comparable between the IOLs. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

Comparison of methods to quantify posterior capsule opacification using forward and backward light scattering.

Purpose To compare forward and backward light scattering measurements to quantify posterior capsule opacification (PCO). Setting Vienna Institute for Research in Ocular Surgery, Vienna, Austria. Design Prospective single‐center study. Methods This observational study comprised consecutive patients scheduled for neodymium:YAG (Nd:YAG) capsulotomy for regeneratory PCO. The corrected distance visual acuity (CDVA) using Early Treatment of Diabetic Retinopathy Study charts and the contrast sensitivity under mesopic and photopic conditions using Pelli‐Robson charts were assessed before an Nd:YAG capsulotomy was performed. Retroillumination images, rotating Scheimpflug scans (Pentacam HR), and straylight meter (C‐Quant) and point‐spread function (PSF) meter (Optical Quality Analysis System) measurements were performed before and after Nd:YAG capsulotomy. Results The study enrolled 50 eyes of 50 patients. The mean uncorrected distance visual acuity and CDVA were 0.76 logMAR ± 0.18 (SD) and 0.68 ± 0.2 logMAR, respectively. The mean log contrast sensitivity (logCS) was 1.2 ± 0.15 logCS under photopic conditions and 1.05 ± 0.15 logCS under mesopic conditions. There was a moderate correlation between the Scheimpflug score and the Automated Quantification of After‐Cataract score (r2 = 0.37, P=.03). Furthermore, a moderate and close to significant correlation between the PSF meter and the straylight meter was observed (r2 = 0.32; P=.07). Conclusion Each of the 4 devices assesses different aspects of a patient’s quality of vision. Further developments should focus on methods that measure forward scatter of light in a large visual angle and are not too patient or examiner dependent. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

A novel murine model for keratoprosthesis.

PURPOSE To establish a murine model for keratoprosthesis. METHODS A miniature keratoprosthesis (m-KPro) device was created consisting of a poly[methyl methacrylate] front part and a titanium back plate, designed after the Boston KPro, which is in widespread clinical use. BALB/c mice were used and a 2 mm in diameter donor cornea was punched out. After 2-mm trepanation of the syngeneic recipient cornea, extracapsular crystalline lens extraction was performed. The m-KPro was assembled onto the cornea button in a similar manner to human KPro implantation. The cornea-device complex was secured to the recipient bed with eight interrupted 11-0 sutures. All mice (n = 10) were followed up for 8 weeks postoperatively. RESULTS All m-KPros were successfully implanted and retained in all 10 animals. There were no critical complications such as endophthalmitis, corneal melting, device extrusions, leakage, extensive inflammation, or weight loss in the animals. We observed mild to moderate donor and host corneal neovascularization in all cases throughout the follow-up period. CONCLUSIONS We have established a novel murine model of KPro implantation that we anticipate will serve as a good experimental system for evaluating host responses after KPro surgery.