Fikret Akata

Photorefractive keratectomy for post-penetrating keratoplasty myopia and astigmatism

Purpose: To determine the safety, effectiveness, and predictability of photorefractive keratectomy (PRK) for the correction of myopia and astigmatism after penetrating keratoplasty. Setting: Gazi University, Medical School, Department of Ophthalmology, Ankara, Turkey. Methods: Photorefractive keratectomy was performed in 16 eyes of 16 patients with postkeratoplasty myopia and astigmatism who were unable to wear glasses due to anisometropia and were contact lens intolerant. They were examined for uncorrected visual acuity (UCVA), best spectacle‐corrected visual acuity (BSCVA), and corneal transplant integrity before and after surgery. Results: The mean follow‐up after PRK was 26.0 months ± 15.7 (SD) (range 12 to 63 months). The mean preoperative spherical equivalent refraction of −4.47 ± 1.39 diopters (D) was −3.39 ± 1.84 D (P > .05) at the last postoperative visit and the mean preoperative cylinder of −5.62 ± 2.88 D was −3.23 ± 1.70 D (P < .05); refractive regression correlated with the amount of ablation performed. The BSCVA decreased in 3 eyes (18.8%), and the UCVA decreased in 2 (12.5%). Six eyes (37.5%) had grade 2 to 3 haze, which resolved spontaneously in 4 eyes within a relatively long time but caused a decrease in BSCVA in 2 (12.5%). Two of the eyes (12.5%) had a rejection episode after PRK and were successfully treated with topical steroids. Conclusions: Photorefractive keratectomy to correct postkeratoplasty myopia and astigmatism appears to be less effective and less predictable than PRK for naturally occurring myopia and astigmatism. Corneal haze and refractive regression are more prevalent, and patient satisfaction is not good.

Results of photorefractive keratectomy in keratoconus suspects at 4 years.

PURPOSE We studied the long-term results of photorefractive keratectomy (PRK) in keratoconus suspects detected by videokeratography (TMS). METHODS Bilateral inferior corneal steepening was detected in 6 candidates for PRK presenting with moderate myopia or astigmatism. Mean follow-up was 44.5 +/- 4.4 months (range, 38 to 54 mo). Mean spherical equivalent refraction was -5.18 +/- 1.60 D (mean sphere, -4.73 D; mean cyclinder, -0.92 D) which was stable for at least the preceding year. The quantitative measurement of inferior corneal steepening (I-S value) was greater than +1.60 (mean, 1.83 +/- 0.11) in all eyes. An Aesculap Meditec Mel 60 excimer laser was used for the PRK procedures and mean follow-up was 44.5 months. Postoperative pachymetric measurements were also performed in 6 eyes. RESULTS Postoperative uncorrected visual acuity was 20/20 in 8 eyes (66.6%) and 20/32 or better in all eyes with a mean postoperative spherical equivalent refraction of -0.70 +/- 0.74 D (mean sphere, -0.63 D; mean cyclinder, -0.39 D). Five eyes (41.6%) were within +/- 0.50 D spherical equivalent refraction. Inferior steepening was associated with thinning of the inferior cornea which was statistically significantly thinner than the superior thickness (Students t-test, P < .05). There were no wound healing problems or any sign that the excimer laser adversely affected the cornea during follow-up. CONCLUSIONS Photorefractive keratectomy seems to be a safe procedure for reducing or eliminating myopia or astigmatism in keratoconus suspect eyes-most probably forme fruste keratoconus-with a stable refraction, but this may be different in eyes with early keratoconus, known to be a progressive disease.

Surgical treatment of hereditary lens subluxations.

BACKGROUND AND OBJECTIVE To evaluate the effectiveness and results of pars plana vitreolensectomy approach with transscleral fixation of intraocular lens in hereditary lens subluxations. METHODS Fifteen eyes of 9 consecutive patients with a mean age of 12.8+/-6.2 years (6-26 years) with hereditary lens subluxation were operated on and the results were evaluated in a prospective study. Surgery was considered if best spectacle corrected visual acuity (BSCVA) was less than 20/70. All eyes underwent a 2-port pars plana vitreolensectomy and transscleral fixation of an intraocular lens (IOL). RESULTS The mean follow-up period was 12.6+/-7.5 months (6-22 months). There was no major intraoperative complication. Preoperatively, 8 eyes (53.3%) had a BSCVA of counting fingers (CF) and 7 eyes (46.6%) had a BSCVA of 20/200 to 20/70. Postoperatively, 14 eyes (93.3%) had a BSCVA of 20/50 or better. None of the patients had IOL decentration or intraocular pressure (IOP) increase during the follow-up period. There was a macular hole formation in 1 eye postoperatively. CONCLUSIONS The early results of pars plana vitreolensectomy with IOL implantation using scleral fixation technique had shown that it not only promises a rapid visual rehabilitation but it is also a relatively safe method. More serious complications, however, may occur in the long term.

Corneal iron ring after hyperopic photorefractive keratectomy

PURPOSE To report the incidence and course of corneal iron deposition after hyperopic photorefractive keratectomy (PRK). SETTING Gazi University, Medical School, Department of Ophthalmology, Ankara, Turkey. METHODS Between January 1995 and December 1997, 62 eyes had PRK to correct hyperopia. RESULTS Nine eyes developed corneal iron ring 5 to 8 months (mean 6.25 months +/- 1.3 [SD]) after PRK for hyperopia. The rings persisted during the mean follow-up of 19 +/- 11.09 months. CONCLUSION The ring-shaped iron deposition after PRK for hyperopia must be differentiated from the Fleischer ring. Our results suggest that the slitlamp findings of peripheral corneal iron deposition in hyperopic PRK patients correlate with achieved correction.

Fluorometholone-induced cataract after photorefractive keratectomy

The use of topical corticosteroids following photorefractive keratectomy (PRK) is widespread. The major complications of potent corticosteroids are glaucoma and cataract formation; in order to decrease these complications, 0.1% fluorometholone administration is usually preferred after PRK. We report here a case of lens opacification which was induced by 0.1% fluorometholone administration after PRK in a period of 4 months. To our knowledge, this is the first reported case of 0.1% fluorometholone-induced cataract after PRK.

Phototherapeutic keratectomy in Schnyder crystalline corneal dystrophy.

Objective: To emphasize the effectiveness of phototherapeutic keratectomy (PTK) in a patient with Schnyder crystalline corneal dystrophy (SCCD). Methods: Case report. Results: Two eyes of a patient with SCCD underwent PTK. Best corrected visual acuity (BCVA) increased from 2/10 to 8/10 (plano/−1.50 × 10) in the right eye in a lit room. BCVA of the left eye was 4/10 (−8.00/−1.50 × 170) and did not change after treatment because of anisometropic amblyopia. No recurrence was detected after 68 months of follow-up. Conclusion: PTK may be effective in the treatment of SCCD, especially if the crystals are the cause of visual disturbance.

Scanning laser polarimetry in corneal topographic changes after photorefractive keratectomy.

Purpose: To examine whether, or not, corneal topographic changes after excimer laser photorefractive keratectomy (PRK) for myopia and myopic astigmatism have any influence on measurements of the retinal nerve fiber layer (NFL) with scanning laser polarimetry. Methods: Retinal NFL thicknesses were determined by scanning laser polarimetry in 17 eyes of 13 patients with myopia and myopic astigmatism before and after PRK. Total ablation depth ranged from 26 to 71 μm. We used the relative ratios for superior and inferior NFL thicknesses which were calculated by dividing the NFL values of respective regions by the nasal value. Results: The mean superior NFL ratio measured was 3.02 ± 0.92 preoperatively, and 3.00 ± 0.76 postoperatively. The mean inferior NFL ratio was 2.95±0.75 preoperatively, and 2.99±0.66 postoperatively. There was no statistically significant difference between preoperative and postoperative NFL measurements (Wilcoxon signed rank test, p > 0.05). Conclusions: Corneal topographic changes after PRK have no significant influence on NFL measurements by scanning laser polarimetry. Our results suggest that scanning laser polarimetry can be used as a reliable method for retinal NFL thickness measurements even after excimer laser PRK.

Primary amyloidosis of an extraocular muscle

Minimal proptosis with limitation of left upward gaze in a 34-year-old female was due to primary amyloidosis of the extraocular muscle.

Effects of perfluorophenanthrene on the human corneal endothelium

AbstractPurpose: To evaluate long term effects of perfluorophenanthrene (C12F24), a perfluorocarbon fluid, in the anterior chamber of the human eye, where residual perfluorophenanthrene was retained in the eye postoperatively. Methods: Slit-lamp microscopic and specular microscopic examinations of 4 eyes of 4 patients were performed. All the eyes were operated for complicated retinal detachment and they were aphakic at the end of the operations. Mean follow-up period was 10 months (6–16 months). Results: Perfluorophenanthrene was seen in the anterior chamber in the first or second day postoperatively as a single drop. In the third week, postoperatively, the first signs of splitting the perfluorophenanthrene (fish egging phenomena) was observed. There was no sign of corneal or anterior segment toxicity with the slit lamp microscopic examinations and the intraocular pressure was within normal limits during the follow-up period in all eyes. However, some structural changes of the corneal endothelium were shown by specular microscopy. Decreased endothelial cell density, are versed illumination pattern in which the normally dark cellular boundaries appear bright and intracytoplasmic light reflecting bodies were signs of cellular damage at the contact sites whereas no significant changes were seen at non contact sites. Conclusion: Residual perfluorophenanthrene in the anterior chamber does not induce gross corneal damageor ocular inflammation, although structural changes indicating the damage of the corneal endothelium, can be shown by specular microscopy at the contact sites. Corneal endothelial changes seem to arise from acontact-dependent effect of the perfluorophenanthrene.

Fungal keratitis secondary to Scedosporium apiospermum infection and successful treatment with surgical and medical intervention

To report a rare case of severe fungal keratitis caused by Scedosporium apiospermum, which was treated with a penetrating tectonic keratoplasty and aggressive medical treatment. A 62-year-old woman with a history of soil contamination of the right eye while planting vegetables presented with a severe corneal abscess and ocular pain. The patient received medical treatment and underwent tectonic keratoplasty. Both corneal scrapings and the corneal button were evaluated microscopically. The samples were sent for aerobic and anaerobic bacterial and fungal cultures. Microbiological examinations showed S. apiospermum. The isolate was sensitive to amphoterycine B, caspofungin, voriconazole, and resistant to fluconazole. No clinical improvement was achieved with topical voriconazole, vancomycin, ceftazidime, and systemic voriconazole. A penetrating tectonic keratoplasty and lensectomy with continuation of anti-fungal therapy achieved satisfactory results. A fungal etiology should be suspected in a progressive and untreatable corneal abscess. Microbiological investigation is very important in early diagnosis. Despite early diagnosis and aggressive treatment, in selected cases removing the infected tissue surgically is vital in preserving the ocular globe and vision.