Walter Sekundo

Six-year follow-up of laser in situ keratomileusis for moderate and extreme myopia using a first- generation excimer laser and microkeratome

Purpose: To evaluate objectively and subjectively the long‐term outcome of laser in situ keratomileusis (LASIK) in patients with high and very high myopia. Setting: Department of Ophthalmology, Philipps University, Marburg, Germany. Methods: Thirty‐three eyes of 19 patients were followed for a mean of 76 months (range 50 to 84 months) after primary LASIK using the Keratom I excimer laser (Schwind) and the ALK microkeratome (Chiron). Refraction, glare, pachymetry, corneal topography, and tear‐film secretion and stability were measured. At the last examination, patients also answered a 14‐item questionnaire. Results: Preoperatively, the mean spherical equivalent was –13.65 diopters (D). At 1 year, it was –0.25 D and after 6 years, –0.88 D. Fifteen percent of eyes lost ≥2 lines of best spectacle‐corrected visual acuity (BSCVA), and 9% gained ≥2 Snellen lines. At the end of the study, 46% of eyes were within ±1.0 D of the attempted corrected and 88% were within ±3.0 D. There were 5 microkeratome‐associated complications; 3 resulted in loss of BSCVA. The latest pachymetry showed a mean corneal thickness of 498.5 &mgr;m (range 396 to 552 &mgr;m). There were no cases of keratectasia. Seventy‐five percent of patients noted an increase in their quality of life. Seventy‐one percent were satisfied with their postoperative visual acuity; however, 75% noticed glare and halos at night. Conclusions: Laser in situ keratomileusis correction of very high myopia did not cause keratectasia in the long term provided the corneal thickness was respected. A flap thickness setting of 130 &mgr;m with a first‐generation microkeratome resulted in a high number of cut failures. Most patients were happy with the results despite a modest level of accuracy and glare.

LASIK for Myopia Using the Zeiss VisuMax Femtosecond Laser and MEL 80 Excimer Laser

PURPOSE To assess the efficacy, safety, and predictability of the VisuMax femtosecond laser (Carl Zeiss Meditec). METHODS In a prospective, multicenter clinical trial, 32 eyes of 17 patients underwent LASIK and flap creation with the VisuMax femtosecond laser and ablation with the MEL 80 excimer laser (Carl Zeiss Meditec). Mean patient age was 35 years (range: 23 to 52 years). Mean preoperative spherical equivalent refraction was -4.04 +/- 1.39 diopters (D) (range: -1.50 to -7.25 D), and the planned flap thickness was 110, 120, 140, and 150 microm. RESULTS At the 3-month postoperative examination, all eyes had best spectacle-corrected visual acuity of 20/25 and uncorrected visual acuity (UCVA) of 20/40; 91% of eyes reached UCVA of 20/20 or better. Ninety-four percent of eyes were within +/- 0.50 D of the planned correction. Complications were limited to one case of suction loss, and no other adverse events were noted at 3 months. The flaps were planar and the mean achieved central flap thickness was 118 +/-9.2 microm for an attempted thickness of 120 microm. CONCLUSIONS The investigators achieved LASIK outcomes exceeding the US Food and Drug Administration guidelines for refractive procedures in this series of myopic eyes using the VisuMax femtosecond laser and MEL 80 excimer laser. The curved contact lens of the applanation glass combined with low suction permitted continuous fixation during treatment.

Capillaries in the epithelium of pterygium

AIM To present new morphological observations of intraepithelial capillaries in pterygium and to provide some explanations for this phenomenon. METHODS The ultrastructural features of pterygia from 26 patients were examined. Surgically excised tissue was processed for conventional light and transmission electron microscopy. RESULTS Individual capillaries within the epithelium of the anterior half towards the head of pterygia were identified in 11 specimens out of 26 pterygia examined (42.3%). The perivascular connective tissue of the intraepithelial capillaries contained fibroblasts, collagen fibrils, and elastin-like material. Epithelial cells surrounding these capillaries showed defects in the basal lamina in contrast with the continuous basal lamina of the endothelium. In the intercellular space of the epithelium an amorphous substance, occasional fibroblast processes, and collagen fibrils were frequently observed. CONCLUSION Capillaries in the epithelium of pterygia are rare, but not exceptional. The ingrowth of these vessels from the stroma into the epithelium can be interpreted as a reaction to hypoxia or deficiency of any other substance transported via the bloodstream. Apparently, the perivascular connective tissue can be used by ingrowing fibroblasts as a migration pathway. The migrating fibroblasts appear to use the defects of the epithelial basal lamina (whether partially or complete) in order to reach the intercellular space. It is possible that collagen fibrils in the epithelial intercellular space have been laid down by fibroblasts which contribute to the pathological dedifferentiation of the conjunctival epithelium.

Intraocular pressure during corneal flap preparation: comparison among four femtosecond lasers in porcine eyes.

PURPOSE To compare the course of intraocular pressure (IOP) during corneal flap preparation using four different femtosecond lasers in porcine globes. METHODS Forty-eight (12 in each group) enucleated globes were successfully cannulated through the optic nerve. Intraocular pressure was measured continuously through the cannula during a normal lamellar flap creation (regular procedure) using four femtosecond lasers (IntraLase, Abbott Medical Optics; VisuMax, Carl Zeiss Meditec AG; Femtec, Technolas Perfect Vision; and Femto LDV, Ziemer Ophthalmic Systems AG). In an additional measurement (worst-case procedure), the patient interface was pressed against the globe with increasing force until the applanation maneuver was automatically aborted by those devices capable of doing so. RESULTS During the regular procedure, the maximum IOP reached was 135±16 mmHg when using the Intra-Lase, 65±20 mmHg with the VisuMax, 205±32 mmHg with the Femtec, and 184±28 mmHg with the Femto LDV. During the worst-case procedure, a maximum IOP of 260±53 mmHg was reached with the IntraLase, 105±13 mmHg with the VisuMax, and 248±51 mmHg with the Femtec. CONCLUSIONS There is considerable variation in IOP among the tested femtosecond lasers during a regular lamellar flap creation and during the worst-case procedure. The VisuMax femtosecond laser seems to cause the lowest IOP rise in both settings.

Five-year results of Small Incision Lenticule Extraction (ReLEx SMILE)

Background To evaluate the 5-year results of Refractive Lenticule Extraction (ReLEx) as Small Incision Lenticule Extraction (SMILE) technique for treatment of myopia and myopic astigmatism. Methods In 2008/2009, the worldwide first 91 eyes were treated using a novel surgical technique (SMILE), where a refractive lenticule of intrastromal corneal tissue is removed though a small incision completely eliminating flap-cutting. 56 out of 91 eyes of the original treatment group volunteered for re-examination 5 years after surgery. Uncorrected distance visual acuity and corrected distance visual acuity after 5 years, objective and manifest refractions as well as evaluation of the interface and corneal surface by slit-lamp examination were documented. Late side effects like corneal scars, corneal ectasia, persistent dry eye symptoms or cataract were documented. Results 5 years postoperatively, no significant change to the 6-month data was found. Spherical equivalent was −0.375 D and therefore close to target refraction (emmetropia). 32 of the 56 eyes had gained 1–2 Snellen lines. There was no loss of 2 or more lines over the 5-year period. Regression in the long term was 0.48 D. Conclusions This first long-term study demonstrates SMILE to be an effective, stable and safe procedure for treatment of myopia and myopic astigmatism. Clinical trial number DE/CA93/KP/07/001. Post-results.

Femtosecond Lenticule Extraction (FLEx) - Results after 12 Months in Myopic Astigmatism

BACKGROUND This clinical trial is focussed on the 12-month results of a new method for refractive correction, femtosecond lenticule extraction (FLEx). PATIENTS AND METHODS In a prospective 6-month study 108 eyes were treated in Erfurt and Marburg. Both a flap and a lenticule of intrastromal corneal tissue were simultaneously cut utilising the Carl Zeiss Meditec AG (Jena, Germany) VisuMax femtosecond laser system. Thereafter, the lenticule was manually removed and the flap repositioned. 31 patients all treated in Erfurt volunteered for a 12-month follow-up. UCVA and BSCVA after 12 months, objective and manifest refraction as well as slit-lamp examination and late side effects were documented. RESULTS 62 eyes of 31 patients were examined in this study. The spherical equivalent before surgery was -4.81 (± 1.16) D; after 12 months -0.15 (± 0.46) D were manifest. No significant change was observed after the 6 months control. Starting with UCVA of 0.12 (± 0.09) before surgery UCVA was 1.10 (± 0.26) after 12 months. In one patient corneal ectasia was diagnosed. All other patients did not have any late side effects. CONCLUSION The stability of the correction of myopic astigmatism with the FLEx procedure is very good. The fact that one patient presented with a corneal ectasia demonstrates that one general problem of refractive corneal surgery persists with this new fs technology.

Long-term ultrastructural changes in human corneas after tattooing with non-metallic substances.

AIM To investigate the ultrastructural appearance and the deposition pattern of dye particles in long term non-metallic corneal tattooing. METHODS Two tattooed human corneas were obtained by keratoplasty. One corneal button was fixed in Karnovsky’s solution and the other in Trumps’ solution. Both corneas were divided and processed for conventional light (LM) and transmission electron microscopy (TEM). Five additional formalin fixed corneas with tattoos were retrieved from paraffin for TEM. The time between tattoo and removal of the corneal button/enucleation ranged from 7 to 61 years. All seven corneas were examined using a Jeol JCXA733 microprobe for wave length dispersive analysis in order to exclude any presence of metallic salts in the tattooed area. RESULTS Histologically, clumps of brown-blackish granules were present mainly in the mid stroma, but also in anterior and partially in the posterior half of the stroma. On TEM, numerous round and oval electron dense particles were seen in the cytoplasm of keratocytes arranged as clusters or large islands. The larger particles appeared black, while the smaller particles were grey. In well fixed tissue a unit membrane was observed around these clusters. No granules were detected in the extracellular matrix. CONCLUSIONS Keratocytes can actively ingest and retain tattooing particles of non-metallic dyes within their cell membrane for very long periods of time.

Surgical treatment of keratoconus at the turn of the 20th century.

PURPOSE This paper reviews surgical modalities for treatment of keratoconus at the threshold of the 20th century. METHODS All ophthalmic literature from 1895 until 1925 in English and German, available at the library of the Institute of Ophthalmology, London, United Kingdom, was studied with respect to this topic. RESULTS Three thermal procedures were described; galvanocauterization with perforation, without perforation, and a non-contact application of heat to the corneal apex. Radial extension of a thermal burn to correct the minus cylinder represented a further modification. Excision of the conical area was suggested either as a lamellar dissection or as a full thickness trephination. Incision of the cone appeared to be less popular. In staged procedures, a combination of galvanocauterization, splitting of the cornea, conjunctival flap, and a subsequent optical iridectomy were applied. CONCLUSION The treatment of keratoconus 100 years ago used refractive surgery to improve visual function by modifying corneal shape.

Evaluation of a posterior vitreous detachment: a comparison of biomicroscopy, B-scan ultrasonography and optical coherence tomography to surgical findings with chromodissection

Purpose:  To find the most reliable and efficient noninvasive technique to clinically detect a posterior vitreous detachment.

The vitreomacular interface in retinal vein occlusion

Purpose:  To evaluate the posterior vitreous adhesion status in patients with a history of central or branch retinal vein occlusion and to compare the results with the natural time‐course of posterior vitreous detachment in healthy age‐related controls.