Assessment of a novel pinhole supplementary implant for sulcus fixation in pseudophakic cadaver eyes.

PurposeTo evaluate a novel small-aperture supplementary implant that applies the principle of pinholes for management of irregular astigmatism, in postmortem human eyes.MethodsPseudophakic human cadaver eyes were imaged by anterior segment optical coherence tomography (AS-OCT) to assess position of the in-the-bag intraocular lens (IOL). Eyes were prepared as per the Miyake-Apple technique. Two versions of the supplementary implant (open-loop and tripod designs) were then inserted into the sulcus of each eye. Evaluations under AS-OCT and from anterior and posterior views of the anterior segment were used to assess IOL fixation, centration, tilt, and interlenticular distance (ILD). This experimental study has been conducted in John A. Moran Eye Center, University of Utah.ResultsNine eyes were selected, with various sizes, primary IOL materials/designs, and Soemmering's ring formation. The open-loop model exhibited a mild degree of decentration and tilt in 2 eyes with zonular dehiscence. Mild decentration and tilt of the tripod were observed in 4 eyes; in 1 additional eye it was centered but mildly tilted. Three eyes with zonular dehiscence had one of the closed loops of the tripod located posteriorly to the ciliary processes. In all cases, an ILD was observed between the lenses (open loop: 0.65±0.13 mm; tripod: 0.41±0.12 mm).ConclusionsIt is important to take into account anatomical aspects related to ciliary sulcus fixation of supplementary IOLs. Both designs evaluated, exhibited appropriate centration and ILD. The open-loop design had less risk of tilt in association with haptics protruding posteriorly through areas of zonular weakness.

Assessment of a new hydrophilic acrylic supplementary IOL for sulcus fixation in pseudophakic cadaver eyes.

PurposeManagement of refractive errors after cataract surgery includes spectacles or contact lens, secondary laser vision correction, intraocular lens (IOL) exchange, or piggyback lens implantation. We evaluated for the first time a single-piece hydrophilic acrylic IOL designed for supplementary sulcus fixation in postmortem pseudophakic human eyes.MethodsPseudophakic human cadaver eyes were imaged by anterior segment optical coherence tomography (AS-OCT) to assess position of the primary IOL. Eyes were prepared as per the Miyake-Apple technique. The supplementary IOL (Medicontur A4 Addon IOL family) was then inserted into the ciliary sulcus. AS-OCT and photographs from anterior and posterior views were used to assess IOL centration, tilt, and interlenticular distance from the primary IOL.ResultsData were obtained from 12 eyes having primary IOLs of varying materials and designs in the bag and representing different sizes of eyes and severity of Soemmering's ring formation. The A4 Addon IOL was successfully inserted into the ciliary sulcus and was well centered in all cases. Four cases of tilt were observed on AS-OCT: three with mild tilt due to pre-existing zonular dehiscence, and one due to a localized area of Soemmering's ring formation. Interlenticular distance ranged from 0.34 to 1.24 mm and was not dependent on severity of Soemmering's ring or type of primary IOL.ConclusionsThe A4 Addon IOL was designed for sulcus fixation as a supplementary lens, with a large diameter, a square-shaped optic, four smooth loop haptics, and a convex-concave optical surface. It exhibited appropriate centration and interlenticular distance with different primary in-the-bag IOLs.

[Cross-linking in an artificial human cornea via induction of tissue transglutaminases]. / Vernetzung einer humanen künstlichen Hornhaut durch Induktion von Tissue-Transglutaminasen.

PURPOSE: In recent years many three-dimensional cornea models have been developed. However, they show poor collagen stability in the stroma. Transglutaminases (Tgases) are calcium-dependent proteins which play an important role in cross-linking of the corneal stroma. The purpose of this study was to find out whether it is possible to induce in vitro cross-linking of the stroma in an artificial hemicornea model with the help of Tgases. MATERIALS AND METHODS: For the construction of the hemicornea, human SV40 adenovector corneal epithelial cells (HCE) and human SV40 adenovector corneal keratocytes (HCK) were cultivated. Confluent HCK cells were treated for 24 h with transforming growth factor beta (TGFb) 1, 2 and 3 at different concentrations as well as with other growth factors and the treated cells were compared to untreated cultivated cells. The quantification of the expression of the Tgases by HCKs was examined with the use of real time PCR, Western blot imaging and immunochemistry. RESULTS: All concentrations of TGFbs used resulted in a significant increase of Tgase-mRNA, Tgase protein level and Tgase activity. The Tgases remained unaffected after treatment with other growth factors in comparison to untreated control cells. Treatment of the hemicornea with TGFb2 showed a very strong contraction and haze in comparison to the untreated hemicornea. CONCLUSION: It has been shown for the first time that TGFb induces a strong expression of Tgases in HCK cells. This effect caused an undesired contraction and haze of the human hemicornea model. Further research is necessary in order to find out whether the induction of Tgases in the HCK cells can be regulated without losing stability of the constructed hemicornea.

Surgical treatment of persistent fetal vasculature and visual rehabilitation: one-year followup.

We present the management and postoperative course of a persistent fetal vasculature (PFV) case. A four-year-old girl visited the Eye Department of Hippokration, General Hospital of Thessaloniki due to reduced visual acuity of her left eye. She was diagnosed with PFV and underwent surgery (lensectomy, capsulorhexis of the posterior capsule, insertion of an intraocular lens in the posterior chamber, and posterior vitrectomy) in order to dissect the PFV. Along with the postoperative medical care, she underwent intensive treatment for amblyopia. The postoperative course was uncomplicated, and the visual acuity of her left eye improved from hand movement to 20/25 with proper correction. Patients with unilateral PFV and gradually deteriorating visual acuity could be good candidates for a combined surgical procedure, as the one described above, with a good prognosis.

Repeatability and reproducibility of a-scan biometry quantitative findings.

PURPOSE: To determine repeatability and reproducibility of A-scan biometry quantitative findings in order to uniformly evaluate lenticular cataract changes. MATERIALS AND METHODS: Seventeen eyes from seventeen cataract patients were examined by three (trainee ophthalmologists). Results (ratio of mean internal lens spikes height/lens anterior surface spike height) were compared using coefficient of variation (CV), repeatability coefficient (CR), and intraclass correlation coefficients (ICC). RESULTS: Intra-observer consistency was CV = 0.36, CR = 0.49, and ICC = 0.778 for the first operator; CV = 0.33, CR = 0.52, and ICC = 0.642 for the second operator; and CV = 0.32, CR = 0.53, and ICC = 0.567 for the third operator. Concerning inter-observer agreement: CV (in 6 of 7 eyes) was > 8%, CR was > 0.21, and intraclass correlation coefficient for all eyes was < 0.81. CONCLUSIONS: Regarding repeatability and reproducibility, although there is a tendency for statistical significance, variability of the results does not allow the use of the method as a complementary clinical tool for comparing results. Standardization of this procedure, in order to achieve higher test reliability, might be the aim of relevant future studies, although there are a number of points that have to be addressed.