Eric D. Donnenfeld

The effect of hinge position on corneal sensation and dry eye after LASIK

PURPOSEnTo investigate the effect of hinge position on corneal sensation and dry eye syndrome after laser in situ keratomileusis (LASIK).nnnDESIGNnProspective, randomized, self-controlled trial.nnnPARTICIPANTSnFifty-two patients >/=18 years of age undergoing bilateral LASIK.nnnINTERVENTIONnPatients underwent bilateral LASIK with the superior-hinge Hansatome microkeratome in one eye and the nasal-hinge Amadeus microkeratome in the other eye. In all eyes, the flaps were 160 micro m thick, with a diameter of 9.5 mm.nnnMAIN OUTCOME MEASURESnMasked Cochet-Bonnet esthesiometry was performed centrally before surgery and at 1 week, 1 month, 3 months, and 6 months after surgery. Dry eye was evaluated at the same time intervals with lissamine green corneal and conjunctival staining, Schirmer testing with anesthesia, and tear-film breakup time. Subjective evaluation of dry eye sensation was performed at 3 and 6 months after surgery.nnnRESULTSnCorneal sensation was reduced in eyes with either superior- or nasal-hinge corneal flaps at 1 week, 1 month, and 3 months after surgery (P < 0.001). Compared with preoperative values, a significant reduction in corneal sensation remained at 6 months in corneas with superior-hinge flaps (P < 0.001) but not in corneas with nasal-hinge flaps (P = 0.263). Mean corneal sensation was greater in corneas with a nasal-hinge flap compared with corneas with a superior-hinge flap at all postoperative visits (P < 0.001). The loss of sensation was greatest at 1 week and showed improvement at each subsequent time interval up to 6 months. Overall, dry eye signs and symptoms were greatest during the immediate postoperative period and improved at all subsequent time intervals. Dry eye signs and symptoms were generally greatest in the eyes with a superior-hinge flap and milder in eyes with a nasal-hinge flap.nnnCONCLUSIONSnThe long posterior corneal nerves, which innervate the cornea, enter the eye at 3- and 9-oclock. A superior-hinge flap transects both arms of the neuroplexus, whereas a nasal hinge transects only the temporal arm. LASIK results in a significant reduction in corneal sensation. Corneal sensation and dry eye signs and symptoms decreased immediately after LASIK and improved at all time periods between 1 week and 6 months in eyes with both a nasal-hinge flap and a superior-hinge flap. However, the loss of corneal sensation and presence of dry eye syndrome were greater in eyes with a superior-hinge flap than in eyes with a nasal-hinge flap.

Comparison of corneal sensation following photorefractive keratectomy and laser in situ keratomileusis.

Purpose: To evaluate the effect of photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) on corneal sensation. Setting: Eye Institute, Medical School of the University of Crete, Heraklion, Greece, and Orasis, Hellenic Eye Center of Athens, Greece. Methods: In a masked study, corneal sensation was measured with the CochetBonnet aesthesiometer in 40 consecutive patients 6 to 12 months following PRK and LASIK (60 mm constitutes normal reading and <40 mm, abnormal). Results: After 6 to 12 months, the mean corneal sensation following PRK was 39.2 mm (range 30 to 55 mm) (mean 9.5 months) and after LASIK, 53.6 mm (range 40 to 60 mm) (mean 9.3 months). The mean correction attempted for PRK was 7.05 diopters (D) (range 2.5 to 12.0 D) and for LASIK, 11.71 D (range 6.0 to 20.0 D). Conclusion: In this group of patients, with correction of primarily severe myopia, corneal sensation was significantly greater after LASIK than after PRK.

Penetration of Topically Applied Ciprofloxacin, Norfloxacin, and Ofloxacin into the Aqueous Humor

PURPOSEnTo determine the intraocular penetration of topically applied fluoroquinolone antibiotics into aqueous humor.nnnMETHODSnThirty-two patients undergoing cataract extraction received either 0.3% ciprofloxacin, 0.3% norfloxacin, or 0.3% ofloxacin topical drops. The patients were given two drops 90 minutes preoperatively and two drops 30 minutes preoperatively. At the time of surgery, 0.1 ml aqueous fluid was aspirated from the anterior chamber and immediately stored at -70 degrees C.nnnRESULTSnConcentrations of ciprofloxacin, norfloxacin, and ofloxacin were determined using a broth dilution bioassay. Morganella morganii with a known minimal inhibitory concentration was used to assay ciprofloxacin and norfloxacin levels. Salmonella enteritidis with a known minimal inhibitory concentration was used to assay ofloxacin levels. Topically applied ciprofloxacin achieved a mean aqueous level of 0.072 microgram/ml (range, 0.02-0.153 microgram/ml). One sample was below the sensitivity of the bioassay. Topical norfloxacin achieved a mean aqueous level of 0.0570 microgram/ml (range, 0.046-0.10 microgram/ml). Seven samples did not reach the sensitivity of the bioassay. Topical ofloxacin achieved a mean level in the aqueous humor of 0.338 microgram/ml (range, 0.078-0.625 microgram/ml). There was no statistically significant difference in intraocular aqueous humor levels of ciprofloxacin versus norfloxacin (P > 0.05). Topical ofloxacin achieved aqueous humor levels significantly higher than either ciprofloxacin or norfloxacin (P < 0.004).nnnCONCLUSIONnOf the currently available topical fluoroquinolone antibiotics, ofloxacin achieves the highest aqueous humor concentrations.

Subconjunctival mitomycin C for the treatment of ocular cicatricial pemphigoid

PURPOSEnThe authors performed a prospective evaluation of the efficacy of treating ocular cicatricial pemphigoid (OCP) with subconjunctival mitomycin C.nnnDESIGNnUnmasked, prospective, internally controlled case series.nnnMETHODSnPatients were eligible for treatment with subconjunctival mitomycin C under three criteria: (1) significant complications of systemic immunosuppressant therapy; (2) markedly asymmetric conjunctival disease; and (3) end-stage OCP. All patients received monocular subconjunctival injections of 0.25 ml of 0.2 mg/ml mitomycin C to both the superior and inferior bulbar conjunctivae in the eye with the more severe disease.nnnRESULTSnNine eyes of nine patients (mean age, 74 years) were treated with subconjunctival mitomycin C to the more-involved eye and were followed for a mean of 23.5 months (range, 12-40 months). Eight of nine patients showed quiescence of their OCP in the treated eye based on serial evaluation of conjunctival cicatrization and grading of conjunctival erythema. Five of the nine untreated eyes showed progression of the conjunctival disease. One patient required concomitant systemic immunosuppressive therapy after subconjunctival mitomycin C. Two patients underwent successful visual rehabilitative surgery in the mitomycin C-treated eye.nnnCONCLUSIONnThe use of subconjunctival mitomycin C may be effective in preventing progression of conjunctival cicatrization and erythema in patients with OCP. No complications of mitomycin C treatment were noted. Long-term follow-up and further investigation into the efficacy of subconjunctival mitomycin C in the management of OCP is warranted.

Flap thickness accuracy ☆ ☆☆ ★ ★★: Comparison of 6 microkeratome models

Purpose: To determine the flap thickness accuracy of 6 microkeratome models and determine factors that might affect flap thickness. Setting: Magill Research Center for Vision Correction, Storm Eye Institute, Medical University of South Carolina, Charleston, South Carolina, USA. Methods: This multicenter prospective study involved 18 surgeons. Six microkeratomes were evaluated: AMO Amadeus, Bausch & Lomb Hansatome®, Moria Carriazo‐Barraquer, Moria M2, Nidek MK2000, and Alcon Summit Krumeich‐Barraquer. Eyes of 1061 consecutive patients who had laser in situ keratomileusis were included. Age, sex, surgical order (first or second cut), keratometry (flattest, steepest, and mean), white‐to‐white measurement, laser used, plate thickness, head serial number, blade lot number, and occurrence of epithelial defects were recorded. Intraoperative pachymetry was obtained just before the microkeratome was placed on the eye. Residual bed pachymetry was measured after the microkeratome cut had been created and the flap lifted. The estimated flap thickness was determined by subtraction (ie, mean preoperative pachymetry measurement minus mean residual bed pachymetry). Results: A total of 1634 eyes were reviewed. Sex distribution was 54.3% women and 45.7% men, and the mean age was 39.4 years ± 10.6 (SD). In addition, 54.5% of the procedures were in first eyes and 45.5%, in second eyes. The mean preoperative pachymetry measurement was 547 ± 34 &mgr;m. The mean keratometry was 43.6 ± 1.6 diopters (D) in the flattest axis and 44.6 ±1.5 D in the steepest axis. The mean white‐to‐white measurement was 11.7 ± 0.4 mm. The mean flap thickness created by the devices varied between head designs, and microkeratome heads had significant differences (P<.05). Factors that explained 78.4% of the variability included microkeratome model, plate thickness, mean preoperative pachymetry, Kmin, surgery order, head serial number, blade lot number, and surgeon. Factors such as age, sex, Kmax, Kaverage, white to white, and laser had no significant correlation to flap thickness. Conclusions: The results demonstrated variability between the 6 microkeratome models. Device labeling did not necessarily represent the mean flap thickness obtained, nor was it uniform or consistent. Thinner corneas were associated with thinner flaps and thicker corneas with thicker flaps. In addition, first cuts were generally associated with thicker flaps when compared to second cuts in bilateral procedures.

Keratoconus Associated with Floppy Eyelld Syndrome

Floppy eyelid syndrome is a recently described entity, which characteristically involves overweight individuals. The characteristic findings are an upper lid that may be readily everted, tarsal laxity, and diffuse papillary conjunctival changes. The cause of floppy eyelid syndrome is believed to be a mechanical disorder due to the eversion of the lids while sleeping. The cause of keratoconus remains uncertain. There are strong proponents to a mechanical etiology for this disease. The authors report five cases of floppy eyelid syndrome with concomitant keratoconus. One patient with bilateral keratoconus had bilateral symmetric floppy eyelid syndrome. The other four patients had asymmetric keratoconus and floppy eyelid syndrome. In all four patients, the keratoconus was significantly worse in the eye with the more severe case of floppy eyelid syndrome. In addition, these four patients all gave a history of sleeping with their head facing predominantly on the side with the floppy eyelid syndrome and keratoconus. Two patients with keratoconus and floppy eyelid syndrome were able to undergo successful contact lens rehabilitation of their keratoconus after treatment of the floppy eyelid syndrome.

Subconjunctival mitomycin C as adjunctive therapy before pterygium excision

PURPOSEnTo evaluate the safety and efficacy of subconjunctival mitomycin C as adjunctive therapy before pterygium surgery.nnnDESIGNnProspective noncomparative case series.nnnPARTICIPANTSnThirty-six eyes of 36 patients.nnnINTERVENTIONnThirty-six eyes of 36 patients prospectively received 0.1 ml of 0.15 mg/ml mitomycin C subconjunctivally injected into the head of the pterygium 1 month before bare sclera surgical excision.nnnMAIN OUTCOME MEASUREnRecurrence of pterygia.nnnRESULTSnThe pterygia resolved in 34 (94%) of 36 eyes, with a recurrence rate of 6% over a mean follow-up of 24.4 months. No wound-healing complication developed in any patient.nnnCONCLUSIONSnSubconjunctival mitomycin C is an effective treatment before pterygium excision. Subconjunctival injection allows exact titration of mitomycin C delivery to the activated fibroblasts and minimizes epithelial toxicity.

Efficacy and wound-temperature gradient of WhiteStar phacoemulsification through a 1.2 mm incision

Purpose: To evaluate the efficacy and wound‐temperature gradients of WhiteStar micropulse technology using bimanual phacoemulsification without an irrigation sleeve through a 1.2 mm incision. Setting: Island Eye Surgicenter, Carle Place, New York, USA. Methods: Ten patients had bimanual phacoemulsification using micropulse technology without an irrigation sleeve through a 1.2 mm clear corneal incision. A thermocouple consisting of a 30‐gauge copper wire was inserted into clear cornea directly adjacent to the wound to digitally record temperature gradients at the wound. Endothelial cell counts were evaluated preoperatively and postoperatively in all patients. Results: All 10 patients maintained corneal clarity with no sign of thermal damage to the wound. The maximum corneal wound temperatures during phacoemulsification ranged from 24°C to 34°C, well below the temperature of collagen shrinkage. The endothelial cell loss at 3 months was 7%. Conclusions: Because of the decreased thermal effect with WhiteStar technology, an irrigation sleeve over the phacoemulsification needle is superfluous. As a result, bimanual phacoemulsification can be safely performed through a 1.2 mm incision.

Transscleral neodymium: YAG thermal cyclophotocoagulation in refractory glaucoma: a preliminary report

Thirty patients treated with transscleral neodymium:YAG laser cyclophotocoagulation (TSYLC) are reported. All patients had advanced glaucoma and had previously undergone one or more surgical procedures that failed, or were unsuitable for surgery. The average preoperative intraocular pressure (IOP) for the group was 43 +/- 12 mmHg. The average follow-up time was 6 months. The average energy level used was 3.8 J (range, 3.5-4.5 J). The patients were divided into two groups. Group 1 consisted of 20 patients in whom laser lesions were applied 3 mm from the limbus. Group 2 consisted of ten patients in whom laser lesions were applied 2 mm from the limbus. Success was defined as an IOP between 22 and 5 mmHg, regardless of the number of treatments required. The overall success rate was 86%. However, group 2 required significantly more retreatment than did group 1. Complications were moderate and transient.

Controlled Evaluation of a Bandage Contact Lens and a Topical Nonsteroidal Anti-inflammatory Drug in Treating Traumatic Corneal Abrasions

BACKGROUNDnTreating traumatic corneal abrasions is a common problem for the ophthalmologist. Traditional management has been the use of a pressure patch. Three different therapeutic modalities were evaluated for their efficacy in treating traumatic corneal abrasions.nnnMETHODSnForty-seven consecutive patients with traumatic corneal abrasions were randomized prospectively in a single-masked, controlled clinical trial which compared the efficacy of (1) pressure patching, (2) a bandage contact lens, and (3) a bandage contact lens with a topical nonsteroidal anti-inflammatory drug (0.5% ketorolac tromethamine).nnnRESULTSnThere was no significant difference in the healing time of the three groups. However, psychometric analysis showed a significant decrease in pain in the group that received a bandage contact lens with a topical nonsteroidal anti-inflammatory drug. There was a significant difference in the ability to return to normal activities in both contact lens groups compared with the pressure-patch group. There was no significant difference among the three groups with respect to photophobia, redness, ocular irritation, headache, or tearing.nnnCONCLUSIONnUse of a bandage contact lens significantly shortens the time required for a patient to return to normal activities. Moreover, addition of a nonsteroidal anti-inflammatory drug to a treatment regimen significantly decreases the pain associated with traumatic corneal abrasions. Use of a bandage contact lens with a topical nonsteroidal anti-inflammatory may prove to be an effective adjunct in treating traumatic corneal abrasions.