Comparison of the effect of cycloplegic versus NSAID eye drops on pain after photorefractive keratectomy.

PURPOSE: To compare the effect of Homatropine and Diclofenac eye drops for reducing pain after photorefractive keratectomy (PRK). METHODS: This randomized, double-masked, interventional study included 32 patients (64 eyes) who underwent bilateral PRK. After operation, patients received Homatropine eye drops in one eye and Diclofenac eye drops in the fellow eye for 48 h. The level of pain was evaluated using visual analogue scale (VAS), verbal rating scale (VRS), and pain rating index (PRI) at 0.5, 24, and 48 h after operation. RESULTS: The level of pain was statistically similar between the two eyes half an hour after operation; however, Diclofenac eyes had significantly less pain 24 h after operation (1.7 ± 1.4 vs 5.8 ± 2.1, P < 0.001 for VAS, 0.6 ± 0.6 vs 2.4 ± 1.1, P < 0.001 for VRS, and 3.4 ± 3.4 vs 12.0 ± 6.9, P < 0.001 for PRI, respectively). Also, 48 h after surgery, the pain scores were less in the Diclofenac eyes (1.6 ± 1.8 vs 3.4 ± 2.8, P < 0.001 for VAS, 0.6 ± 0.6 vs 1.2 ± 0.9, P < 0.001 for VRS, and 3.3 ± 3.7 vs 6.5 ± 6.2, P < 0.001 for PRI). No case with delayed epithelial healing in both groups was observed. CONCLUSION: The effect of Homatropine seems to be lower compared to Diclofenac for reducing pain after photorefractive keratectomy.

Effect of Homatropine eye drops on pain after photorefractive keratectomy: A pilot study.

PURPOSE: To assess the effect of homatropine eye drops on pain after photorefractive keratectomy (PRK). METHODS: This randomized, double masked, interventional study included 15 patients (30 eyes) who underwent bilateral PRK. After operation, patients received homatropine eye drops, 4 times daily in only one eye (homatropine eye). The level of pain was evaluated using visual analogue scale (VAS), verbal rating scale (VRS) and pain rating index (PRI) at 0.5, 24 and 48 h after operation. RESULTS: The level of pain was statistically similar between the two eyes half an hour after operation, however, homatropine eyes had significantly less pain 24 h after operation compared to fellow eyes (2.5 ± 1.9 vs 5.3 ± 2.5, P = 0.004 for VAS, 2.0 ± 1.2 vs 3.2 ± 0.9, P = 0.023 for VRS, and 9.4 ± 5.7 vs 16.0 ± 9.0, P = 0.031 for PRI). Also, 48 h after surgery, the pain scales were less in the homatropine eyes (2.3 ± 1.7 vs 4.0 ± 2.1, P = 0.014 for VAS, 1.6 ± 1.0 vs 2.5 ± 1.0, P = 0.038 for VRS, and 6.8 ± 5.7 vs 12.0 ± 8.9, P = 0.005 for PRI). No delayed epithelial healing was observed. CONCLUSION: Homatropine eye drops may be useful for reducing pain after Photorefractive keratectomy.

Determining corneal power using Pentacam after myopic photorefractive keratectomy.

PURPOSE: To assess the accuracy of Pentacam Scheimpflug camera for corneal power measurement in eyes with previous photorefractive keratectomy for myopia. METHODS: In this comparative interventional case series, 35 eyes of 35 patients who had myopic photorefractive keratectomy were studied. Corneal power was measured by conventional topography and Pentacam Scheimpflug camera, and equivalent keratometry readings (EKR) in different central corneal rings (0.5 to 4.5 mm), true net power and simulated keratometry (K) measurements as well as those obtained using Shammas no-history, Koch-Maloney and Haigis methods were compared with clinical history method. RESULTS: All corneal power measurements except for the topography simulated K and true net power values were statistically similar to the clinical history values. Simulated keratometry and 4.5-mm EKR values were more closely correlated with clinical history method. Shammas formula, Pentacam simulated K and 3-, 4- and 4.5-mm EKR provided a 95% confidence interval within +/-0.50 D of the mean clinical history method value, among these, the width of the 95% limits of agreement (LoA) was narrower for Shammas and Pentacam simulated K and 4.5-mm EKR values; however, considerably large 95% LoA were found between each of these values and those obtained with the clinical history method. Estimated preoperative keratometry was statistically similar to the preoperative measurement; however, estimated refractive change was different from actual value. CONCLUSIONS: The Pentacam 4.5-mm EKR and simulated keratometry may be used as an alternative to clinical history method to predict corneal power when pre-keratorefractive surgery data are unavailable; however, wide LoA should be considered in the calculations.

Interocular differences of the Pentacam measurements in normal subjects.

PURPOSE: The aim of this study was to determine the interocular differences of the Pentacam corneal measurements in a normal population. METHODS: A retrospective analysis was performed on 550 eyes of 275 consecutive subjects evaluated for refractive surgery at the Rassoul Akram Hospital, Iran University of Medical Sciences. A Pentacam Scheimpflug camera was used for corneal measurements. Statistical analysis was performed to determine the normal levels of the difference between the two eyes. RESULTS: One hundred and four men and 171 women with a mean age of 29.1 +/- 7.73 years were evaluated. The mean (range) interocular difference was 2.17 (zero to 21) microm for maximum anterior elevation (AEmax), 3.62 (zero to 31) microm for maximum posterior elevation (PEmax), 8.42 (zero to 30) microm for minimum corneal thickness (CTmin), 0.06 (zero to 0.4) mm(3) for three millimetre corneal volume (CV3), 0.19 (zero to 1.2) mm(3) for five millimetre corneal volume (CV5), 0.44 (zero to 2.9) mm(3) for seven millimetre corneal volume (CV7), 0.24 (zero to 2.5) dioptres for the mean keratometry (Km) and 0.39 (zero to 2.5) D for measurements of the corneal dioptric power in the steepest meridian (Kmax). CONCLUSIONS: Individuals with differences greater than 17.4 microm in AEmax, 29.1 microm in PEmax, 29.6 microm in CTmin, 2 D in Km, 2.27 D in Kmax, 0.32 in CV3, 1.05 in CV5, and 2.6 in CV7 between eyes represent less than 0.5 per cent of the population. An interocular difference outside the normal range should alert the clinician to examine for other parameters that are more predictive of post-refractive surgical ectasia.

Traumatic wound dehiscence and lens extrusion after penetrating keratoplasty.

PURPOSE: The purpose of this study was to investigate risk factors for and results of treatments in patients with traumatic wound dehiscence and lens extrusion after penetrating keratoplasty. METHODS: In this retrospective case series, 7 eyes (4 right eyes and 3 left eyes) of 7 patients who had traumatic wound dehiscence and lens extrusion were studied at Rassoul Akram Hospital. Six patients were male and one patient was female. After emergency treatment for the trauma, the wound was checked under general anesthesia, and anterior vitrectomy was performed. The iris was repositioned as needed and the dehiscence site was sutured in all patients using 10-0 nylon thread. Follow up was similar to that after keratoplasty. All recorded data were statistically analyzed using SPSS software (version 15; SPSS Inc., Chicago, IL). RESULTS: Mean age at trauma was 21 years (range, 10-30 years), and the mean interval between keratoplasty and trauma was 15.6 months (range, 2.5-26.5 months). Mean best-corrected visual acuity of patients before blunt trauma and after final treatment was 20/80 and 20/160, respectively. In one case, visual acuity decreased to light perception after final treatment. The dehiscence site was superior to the graft in 4 patients. Hitting by a hand was the cause of most cases of blunt trauma. No cases of endophthalmitis were seen. CONCLUSION: Patients who undergo penetrating keratoplasty are susceptible to graft wound dehiscence resulting from trauma, especially during the first year after keratoplasty. This type of dehiscence is more prevalent in young people, who engage in more social activities and are more exposed to trauma that may lead to blindness. Patient education about the effects of trauma, use of protective eye shields by patients, and performance of lamellar keratoplasty instead of penetrating keratoplasty can decrease trauma and its effects in these patients.