Advanced Surface Ablation-Photorefractive Keratectomy (ASA-PRK): Safety and Clinical Outcome for the Correction of Mild to Moderate Myopia with a Thin Cornea

PURPOSE: To evaluate the safety, clinical outcome, and change in higher-order wavefront aberrations (HOAs) of Advanced Surface Ablation-Photorefractive Keratectomy (ASA-PRK) for the correction of mild to moderate myopia in cases with a thin cornea. METHODS: ASA-PRK was performed, using a rotary epithelial scrubber, post-laser chilled BSS(R) irrigation, and bandage contact lens, in 127 eyes of 70 patients who had a preoperative spherical equivalent within -7.0 D and who were followed-up for more than six months. The patients were divided into two groups, according to their central corneal thickness (CCT), by ultrasonic pachymetry (Group: CCT520 micrometer, 95 eyes, mean 552.3+/-24.8 micrometer). The clinical outcomes of Group I and II were compared. RESULTS: At six months, 100% of Group I (32/32 eyes) and 93.7% of Group II (89/95 eyes) had an UCVA of 1.0 or better (p>0.05). At six months, a spherical equivalent within 0.5 D of emmetropia was observed in 100% (32/32) of the eyes in Group I and in 94.7% (90/95) of the eyes in Group II (p>0.05). At the 12-month follow-up, all eyes showed good stability of the refractive errors, and none showed corneal haze of grade 1 or more, loss of two or more lines of BSCVA, or serious iatrogenic keratectasia. The magnitude of total HOAs, spherical ablation, and coma were significantly higher six and 12 months after surgery in both groups (p0.05). CONCLUSIONS: ASA-PRK performed on patients with mild to moderate myopia and a thin cornea (> or =490 micrometer) showed a high level of efficacy, predictability, stability, and safety. There was no statistically significant difference in surgically induced HOAs between Groups I and II. The authors suggest that ASA-PRK be used for the correction of mild to moderate myopia, especially in cases with a thin cornea. Further study will be needed to determine the safety of this procedure for thinner corneas in surface keratorefractive surgery.

Visual Loss in One Eye after Spinal Surgery

PURPOSE: To report a patient who developed an unusual combination of central retinal artery occlusion with ophthalmoplegia following spinal surgery in the prone position. METHODS: A 60-year-old man underwent a cervical spinal surgery in the prone position. Soon after recovery he could not open his right eye and had ocular pain due to the general anesthesia. Upon examination, we determined that he had a central retinal artery occlusion with total ophthalmoplegia. RESULTS: Despite medical treatment, optic atrophy was still present at the following examination. Ptosis and the afferent pupillary defect disappeared and ocular motility was recovered, but visual loss persisted until the last follow-up. CONCLUSIONS: A prolonged prone position during spinal surgery can cause external compression of the eye, causing serious and irreversible injury to the orbital structures. Therefore, if the patient shows postoperative signs of orbital swelling after spinal surgery the condition should be immediately evaluated and treated.

Efficacy of Anterior Chamber Paracentesis in Intravitreal Triamcinolone Injection

PURPOSE: To investigate the efficacy of anterior chamber paracentesis in intravitreal triamcinolone acetonide injection (IVTA). METHODS: A prospective, randomized clinical trial was conducted on 30 eyes of 30 patients undergoing IVTA. Eyes were randomly divided into two groups, those which had undergone anterior chamber paracentesis (Group 1, 15 eyes) and those which had not (Group 2, 15 eyes). We analyzed postoperative changes in intraocular pressure (IOP) in each group. RESULTS: In group 1, the mean preoperative IOP was 15.33+/-1.72 mmHg; postoperative IOP at 2 and 15 minutes was 7.80+/-1.47 and 11.73+/-1.67 mmHg, respectively. In group 2, there was significant elevation of IOP (46.73+/-8.26 mmHg) 2 minutes after the injection, although this was reduced to the normal range (16.13+/-2.61 mmHg) within 15 minutes. CONCLUSIONS: Routine anterior chamber paracentesis seems to be inappropriate considering the brief elevation in IOP that immediately follows IVTA.