Separate effects of the microkeratome incision and laser ablation on the eye’s wave aberration

microkeratome, incision,laser ablation, wave aberration
Am J Ophthalmol. 2003 Aug;136(2):327-37.

Separate effects of the microkeratome incision and laser ablation on the eye’s wave aberration.

Abstract

PURPOSE:

To study the optical changes induced by the microkeratome cut, the subsequent laser ablation, and the biomechanical healing response of the cornea in normal laser in situ keratomileusis (LASIK) eyes.

DESIGN:

Prospective randomized clinical trial.

METHODS:

A Hansatome microkeratome was used to cut a corneal flap in one eye (study eye) of 17 normal myopic patients and a subsequentlaser ablation was performed 2 months after this initial microkeratome incision. Control eyes received conventional LASIK treatments at the latter time point. The wave aberration of both the study and contralateral control eyes were measured over a 6-mm pupil with a Shack-Hartmann wavefront sensor for all preoperative, postflap cut, and postablation visits.

RESULTS:

The eye’s higher order aberrations had a small, but significant increase (P =.03) of approximately 30% 2 months after cutting a flap. No systematic changes were observed in nearly all Zernike coefficients from their preoperative levels at 2 months postflap cut. A significant difference between the study and control eyes was observed for one trefoil mode, Z(3)(3) (P =.04).

CONCLUSIONS:

There was a wide variation in the response of individual Zernike modes across patients after cutting a flap. The majority of spherical aberration induced by the LASIK procedure seems to be due to the laser ablation and not the microkeratome cut. In addition, the total and higher order root mean square of wavefront errors were nearly identical for both the study and control eyes 3-months after the laser ablation, indicating that a procedure in which the incision and the ablation are separated in time to better control aberrations does not compromise the outcome of a conventional LASIK treatment.

Wound healing profiles of hyperopic-small incision lenticule extraction (SMILE).

Wound healing,hyperopic,small incision lenticule extraction,SMILE
Sci Rep. 2016 Jul 15;6:29802. doi: 10.1038/srep29802.

Wound healing profiles of hyperopic-small incision lenticule extraction (SMILE).

Abstract

Refractive surgical treatment of hyperopia still remains a challenge for refractive surgeons. A new nomogram of small incision lenticule extraction (SMILE) procedure has recently been developed for the treatment of hyperopia. In the present study, we aimed to evaluate the wound healing and inflammatory responses of this new nomogram (hyperopic-SMILE), and compared them to those of hyperopic-laser-assisted in situ keratomileusis(LASIK), using a rabbit model. A total of 26 rabbits were used, and slit lamp biomicroscopy, autorefractor/keratometer, intraocular pressure measurement, anterior segment optical coherence tomography, corneal topography, and in vivo confocal microscopy examinations were performed during the study period of 4 weeks. The corneas were then harvested and subject to immunofluorescence of markers for inflammation (CD11b), wound healing (fibronectin) and keratocyte response (HSP47). The lenticule ultrastructual changes were also analyzed by transmission electron microscopy. Out results showed that hyperopic-SMILE effectively steepened the cornea. Compared to hyperopic-LASIK, hyperopic-SMILE had less postoperative wound healing response and stromal interface reaction, especially in higher refractive correction. However, compared to myopic-SMILE, hyperopic-SMILE resulted in more central deranged collagen fibrils. These results provide more perspective into this new treatment option for hyperopia, and evidence for future laser nomogram modification

A prospective comparison of phakic collamer lenses and wavefront-optimized laser-assisted in situ keratomileusis for correction of myopia.

LASIK, Super Vision Test, collamer lens,low-luminance contrast sensitivity,night vision
Clin Ophthalmol. 2016 Jun 29;10:1209-15. doi: 10.2147/OPTH.S106120. eCollection 2016.

A prospective comparison of phakic collamer lenses and wavefront-optimized laser-assisted in situ keratomileusis for correction of myopia.

Abstract

PURPOSE:

The aim of this study was to evaluate and compare night vision and low-luminance contrast sensitivity (CS) in patients undergoing implantation of phakic collamer lenses or wavefront-optimized laser-assisted in situ keratomileusis (LASIK).

PATIENTS AND METHODS:

This is a nonrandomized, prospective study, in which 48 military personnel were recruited. Rabin Super Vision Test was used to compare the visual acuity and CS of Visian implantable collamer lens (ICL) and LASIK groups under normal and low light conditions, using a filter for simulated vision through night vision goggles.

RESULTS:

Preoperative mean spherical equivalent was -6.10 D in the ICL group and -6.04 D in the LASIK group (P=0.863). Three months postoperatively, super vision acuity (SVa), super vision acuity with (low-luminance) goggles (SVaG), super vision contrast (SVc), and super vision contrast with (low luminance) goggles (SVcG) significantly improved in the ICL and LASIK groups (P<0.001). Mean improvement in SVaG at 3 months postoperatively was statistically significantly greater in the ICL group than in the LASIK group (mean change [logarithm of the minimum angle of resolution, LogMAR]: ICL =-0.134, LASIK =-0.085; P=0.032). Mean improvements in SVc and SVcG were also statistically significantly greater in the ICL group than in the LASIK group (SVc mean change [logarithm of the CS, LogCS]: ICL =0.356, LASIK =0.209; P=0.018 and SVcG mean change [LogCS]: ICL =0.390, LASIK =0.259; P=0.024). Mean improvement in SVa at 3 months was comparable in both groups (P=0.154).

CONCLUSION:

Simulated night vision improved with both ICL implantation and wavefront-optimized LASIK, but improvements were significantly greater with ICLs. These differences may be important in a military setting and may also affect satisfaction with civilian vision correction.

 

Cataract Surgery on the Previous Corneal Refractive Surgery Patient

Cataract Surgery, Refractive surgery, Lasik, RK, Complications
Surv Ophthalmol. 2016 Jul 13. pii: S0039-6257(15)30064-3. doi: 10.1016/j.survophthal.2016.07.001. [Epub ahead of print]

Cataract Surgery on the Previous Corneal Refractive Surgery Patient.

Abstract

Cataract surgery in cases with previous corneal refractive surgery may be a major challenge for the ophthalmologist. The refractive outcome of the case deserves special attention in the preoperative planning process, which should be tailored for the type of prior refractive procedure: incisional, ablative under a flap, or on the corneal surface. Avoiding refractive surprise after cataract surgery in these cases is principally dependent upon the accuracy of the IOL calculation, together with the selection of the appropriate biometric formula for each case. Modern techniques for cataract surgery help surgeons to move towards the goal of cataract surgery as a refractive procedure free from refractive error. We give practical guidelines for the cataract surgeon in the management of these challenging cases.

Abstract

Cataract surgery in cases with previous corneal refractive surgery may be a major challenge for the ophthalmologist. The refractive outcome of the case deserves special attention in the preoperative planning process, which should be tailored for the type of prior refractive procedure: incisional, ablative under a flap, or on the corneal surface. Avoiding refractive surprise after cataract surgery in these cases is principally dependent upon the accuracy of the IOL calculation, together with the selection of the appropriate biometric formula for each case. Modern techniques for cataract surgery help surgeons to move towards the goal of cataract surgery as a refractive procedure free from refractive error. We give practical guidelines for the cataract surgeon in the management of these challenging cases.

Avoiding refractive surprise after cataract surgery in these cases is principally dependent upon the accuracy of the IOL calculation, together with the selection of the appropriate biometric formula for each case. Modern techniques for cataract surgery help surgeons to move towards the goal of cataract surgery as a refractive procedure free from refractive error. We give practical guidelines for the cataract surgeon in the management of these challenging cases

Retinal neurodegeneration associated with peripheral nerve conduction and autonomic nerve function in diabetic patients.

Retinal neurodegeneration,peripheral nerve conduction,autonomic nerve function,diabetic patients
Am J Ophthalmol. 2016 Jul 2. pii: S0002-9394(16)30312-9. doi: 10.1016/j.ajo.2016.06.038. [Epub ahead of print]

Retinal neurodegeneration associated with peripheral nerve conduction and autonomic nerve function in diabetic patients.

Abstract

OBJECTIVE:

In this study, we evaluated the correlation of retinal thickness with peripheral nerve conduction and autonomic nerve function in diabetic patients.

DESIGN:

Cross-sectional study.

METHODS:

Medical records of 160 patients (mean age, 63.61 ± 12.52 years) with diabetes without diabetic retinopathy or mild non-proliferative diabetic retinopathy (NPDR) were reviewed. The mean retinal thickness of the parafoveal area and ganglion cell/inner plexiform layer (GC-IPL) thickness in six macular regions were measured using optical coherence tomography. Peripheral nerve conduction studies were conducted on peroneal and posterior tibial motor nerves, and the sural sensory nerve. Five cardiovascular autonomic function tests were performed. We classified patients into groups by severity of peripheral neuropathy and autonomic dysfunction and analyzed the correlations with mean retinal thickness.

RESULTS:

The mean retinal thickness of the parafovea was 315.05 ± 12.70 μm; and mean macular GC-IPL thickness was 79.89 ± 4.70 μm. Macular GC-IPL thickness showed significant correlation with peripheral nerve conduction (no peripheral neuropathy vs. definite peripheral neuropathy: 82.0 ± 4.8 μm vs. 75.2 ± 3.8 μm, p < 0.001). GC-IPL thickness decreased with severity of autonomic nerve dysfunction (no/mild dysfunction vs. severe dysfunction: 81.2 ± 6.6 μm vs. 77.6 ± 5.9 μm, p = 0.005). There was no significant correlation between the retinal thickness of the parafovea and electrodiagnostic tests.  Macular GC-IPL thickness showed significant correlation with peripheral nerve conduction (no peripheral neuropathy vs. definite peripheral neuropathy: 82.0 ± 4.8 μm vs. 75.2 ± 3.8 μm, p < 0.001). GC-IPL thickness decreased with severity of autonomic nerve dysfunction (no/mild dysfunction vs. severe dysfunction: 81.2 ± 6.6 μm vs. 77.6 ± 5.9 μm, p = 0.005). There was no significant correlation between the retinal thickness of the parafovea and electrodiagnostic tests.

CONCLUSION:

The decrease of GC-IPL thickness was positively correlated with both peripheral nerve conduction and autonomic nerve function in diabetic patients who presented with no diabetic retinopathy or mild NPDR.

Characteristics of Peripapillary Staphylomas Associated with High Myopia Determined by Swept-source Optical Coherence Tomography

intrachoroidal cavitation, peripapillary staphyloma, swept-source optical coherence tomography
Am J Ophthalmol. 2016 Jun 27. pii: S0002-9394(16)30306-3. doi: 10.1016/j.ajo.2016.06.033. [Epub ahead of print]

Characteristics of Peripapillary Staphylomas Associated with High Myopia Determined by Swept-source Optical Coherence Tomography.

Abstract

PURPOSE:

To analyze the morphological features of peripapillary staphylomas associated with high myopia by swept-source optical coherence tomography (OCT).

DESIGN:

Validity analysis.

METHODS:

Highly myopic patients (refractive error >8.0 diopters or axial length >26.5 mm) with a peripapillary staphyloma who had undergone swept-source OCT were studied. The non-highly myopic fellow eyes in patients with unilateral high myopia were also studied. The presence of a peripapillary staphyloma was determined by stereoscopic ophthalmoscopic examinations. The OCT features of the peripapillary staphylomas and other peripapillary lesions were evaluated.

RESULTS:

Twenty-five eyes of 16 patients were studied. Twenty-two eyes were highly myopic and remaining 3 eyes of the patients with unilateral high myopia were non-highly myopic. A peripapillary staphyloma was seen in the swept-source OCT images as a gently sloping excavation around the optic disc in all of the 25 eyes. The posterior sclera in the area of a peripapillary staphyloma was observed to bow posteriorly with the local curvature steeper than the curvature of the adjacent scleral regions. The sclera at the edge of a peripapillary staphyloma appeared to be elevated inwardly from the surrounding sclera, and the choroid at the staphyloma edge appeared to be compressed and thinned. A peripapillary intrachoroidal cavitation was a frequent complication and found in 13 eyes with a peripapillary staphyloma (52.5 %).

CONCLUSIONS:

Swept-source OCT can detect the slight changes of the sclera and choroid in the area of a peripapillary staphyloma, and we recommend its use in determining the presence of a peripapillary staphyloma.

Copyright © 2016 Elsevier Inc. All rights reserved.

KEYWORDS:

intrachoroidal cavitation; peripapillary staphyloma; swept-source optical coherence tomography

Fundus Photography as a Screening Method for Diabetic Retinopathy in Children with Type 1 Diabetes: Outcome of the Initial Photography.

Fundus Photography, Screening,Diabetic Retinopathy,Children,Type 1 Diabetes, Outcome
Am J Ophthalmol. 2016 Jul 2. pii: S0002-9394(16)30311-7. doi: 10.1016/j.ajo.2016.06.037. [Epub ahead of print]

Fundus Photography as a Screening Method for Diabetic Retinopathy in Children with Type 1 Diabetes: Outcome of the Initial Photography.

Abstract

PURPOSE:

To determine the success rate of the initial fundus photography session in producing gradable images for screening diabetic retinopathy in children <18 years of age with type 1 diabetes, and to analyze outcome-associated factors.

DESIGN:

Retrospective observational cohort study.

METHODS:

Mydriatic red-free monochromatic 60° digital fundus images centered on the macula and optic disc of 213 patients were graded. Photography success, classified as “complete” if both images of both eyes were gradable, “partial” if both images of one eye were gradable, “macula centered image(s) only” and “unsuccessful” if neither macula centered image was gradable.

RESULTS:

Complete success was reached in 97 (46%; 95% confidence interval [CI], 39-52) patients, at least partial success in 153 (72%; 95%CI, 65-78) patients, success of macula centered image(s) only in 47 (22%; 95%CI, 17-28) patients, and in 13 (6%; 95%CI, 3-10) patients fundus photography was unsuccessful. Macula centered images were more often gradable in both eyes than optic disc centered images (P<0.001). Success of photography did not differ between right and left eye. Gender, age at diagnosis of T1D, and the duration of diabetes, age and glycemic control at the time of initial photography were unassociated with complete success. Partial success tended to decrease with increasing age category (P=0.093), and the frequency of gradable macula centered image(s) only increased with increasing age (P=0.043).  Gender, age at diagnosis of T1D, and the duration of diabetes, age and glycemic control at the time of initial photography were unassociated with complete success. Partial success tended to decrease with increasing age category (P=0.093), and the frequency of gradable macula centered image(s) only increased with increasing age (P=0.043).

CONCLUSIONS:

Less than half of the children achieved complete success, but in only 6% initial fundus photography was unsuccessful indicating its value in assessing retinopathy in the pediatric setting.

Stevens-Johnson syndrome and corneal ectasia: management and a case for association

Am J Ophthalmol. 2016 Jul 4. pii: S0002-9394(16)30313-0. doi: 10.1016/j.ajo.2016.06.039. [Epub ahead of print]

Stevens-Johnson syndrome and corneal ectasia: management and a case for association.

Abstract

PURPOSE:

To report the occurrence of corneal ectasia (ECT) in patients with history of Stevens-Johnson syndrome (SJS), and to make the case for an association between these two diagnoses. We also report the impact of prosthetic replacement of the ocular surface ecosystem (PROSE) treatment on visual acuity (VA) in these patients.

DESIGN:

Retrospective cohort study METHODS: A manufacturing database of PROSE patients from 2002-2014 at Boston Foundation for Sight (BFS), a single center clinical practice, was reviewed to identify patients with diagnoses of both SJS and ECT.

RESULTS:

Nine patients were identified with diagnoses of both SJS and ECT. In each case, review of the medical record revealed that diagnosis of SJS preceded that of ECT. The prevalence of ECT in this population exceeded that in the general population (p < 0.0001). Videokeratography was available for thirteen eyes in seven patients; using Krumeich’s classification of keratoconus, three eyes were found to be at stage 1, three at stage 2, one at stage 3, and six at stage 4. Sixteen of eighteen eyes underwent PROSE treatment. Of these sixteen eyes, initial median VA was 20/200 (range, CF-20/20; logMAR 1.0). Median VA after PROSE customization was 20/30 (range, 20/60-20/15; logMAR 0.1761, p < 0.0025).Of these sixteen eyes, initial median VA was 20/200 (range, CF-20/20; logMAR 1.0). Median VA after PROSE customization was 20/30 (range, 20/60-20/15; logMAR 0.1761, p < 0.0025).

CONCLUSIONS:

ECT occurs in a higher than expected rate in patients with history of SJS. PROSE treatment improves VA in these patients. The basis of the association between SJS and ECT is considered as well as the role of plausible contributory factors such as corneal microtrauma and matrix metalloproteinases.

Penetrating keratoplasty for keratoconus with and without resolved corneal hydrops: long-term results

Corneal neovascularization, hydrops, endothelial rejection, corneal transplant
Am J Ophthalmol. 2016 Jul 12. pii: S0002-9394(16)30329-4. doi: 10.1016/j.ajo.2016.07.001. [Epub ahead of print]

Penetrating keratoplasty for keratoconus with and without resolved corneal hydrops: long-term results.

Abstract

PURPOSE:

To evaluate the long-term risk of endothelial rejection, graft survival, and associated factors following penetrating keratoplasty (PK) for keratoconus, with and without prior resolved corneal hydrops.

DESIGN:

Retrospective cohort study.

METHODS:

Primary outcome measures were endothelial rejection-free survival and failure-free survival. Secondary outcome measures were corneal neovascularization following hydrops and complications following PK.

RESULTS:

245 eyes underwent PK for keratoconus with mean follow-up of 5.6 ± 3.6 years. Eyes with prior hydrops (n=74) had lower endothelial rejection-free survival rates compared to eyes without prior hydrops: 86.5 ± 4.0% vs 86.5 ± 2.6% at 1 year, 61.0 ± 6.2% vs 76.9 ± 3.3% at 5 years, and 45.8 ± 10.1% vs 70.9 ± 4.3% at 10 years, respectively (p=0.023). Multivariate analysis identified factors associated with endothelial rejection as: age ≤25 years (p=0.017), corneal neovascularization (p=0.001), donor trephination size >8mm (p=0.017), and poor clinic attendance (p=0.015). There was no difference in the failure-free survival rates with and without prior hydrops: 98.6 ± 1.3% vs 97.1 ± 1.3% at 1 year, 97.3 ± 1.9% vs 95.1 ± 1.9% at 5 years, and 97.3 ± 1.9% vs 92.2 ± 2.7% at 10 years, respectively (p=0.42). Corneal neovascularization was present at the time of PK in 44.6% of eyes with prior hydrops and 7.6% without prior hydrops (p<0.001).  Multivariate analysis identified factors associated with endothelial rejection as: age ≤25 years (p=0.017), corneal neovascularization (p=0.001), donor trephination size >8mm (p=0.017), and poor clinic attendance (p=0.015). There was no difference in the failure-free survival rates with and without prior hydrops: 98.6 ± 1.3% vs 97.1 ± 1.3% at 1 year, 97.3 ± 1.9% vs 95.1 ± 1.9% at 5 years, and 97.3 ± 1.9% vs 92.2 ± 2.7% at 10 years, respectively (p=0.42). Corneal neovascularization was present at the time of PK in 44.6% of eyes with prior hydrops and 7.6% without prior hydrops (p<0.001).

CONCLUSIONS:

Corneal neovascularization, a frequent complication of corneal hydrops, was associated with increased risk of endothelial rejection following PK. However, allograft survival was similar in eyes with and without prior hydrops.

Contralateral assessment of sub-Bowman keratomileusis (SBK) microkeratome suction duration on laser-assisted in-situ keratomileusis (LASIK) flap characteristics

Corneal flap, LASIK, Laser-assisted in-situ keratomileusis, Suction
J Curr Ophthalmol. 2016 Apr 20;28(2):65-8. doi: 10.1016/j.joco.2016.03.004. eCollection 2016.

Contralateral assessment of sub-Bowman keratomileusis (SBK) microkeratome suction duration on laser-assisted in-situ keratomileusis (LASIK) flap characteristics.

Abstract

PURPOSE:

To describe the effect of prolonging the standard suction duration during laser-assisted in-situ keratomileusis (LASIK) and its effect on flap thickness and hinge length using sub-Bowman keratomileusis (SBK) microkeratome.

METHODS:

Fifty-six eyes (28 patients) were included and divided into 2 groups; Group-A: eyes with flatter corneas (36 eyes, 18 patients) and mean keratometric readings ranging from 40.13 to 43.71 diopters (D). Group-B: eyes with steeper corneas (20 eyes, 10 patients) with mean keratometric readings ranging from 43.85 to 46.72 D. One-Use-Plus SBK microkeratome was used for flap creation. For right eyes, flap was created immediately once suction was built up. In left eyes, the surgeon waited for 10 s after suction was built up before flap creation. Flap hinge length and flap thickness were measured using surgical caliper and ultrasonic pachymetry, respectively.

RESULTS:

Statistically significant differences were observed in corneal flap hinge size between right eyes versus left eyes, with a mean of 3.98 ± 0.48 vs. 3.78 ± 0.55 mm (p < 0.001). Mean flap thickness in both eyes did not prove to be statistically significantly different with either surgical technique (90.2 ± 1.68 vs. 90.07 ± 1.44 μm, p = 0.8). Sub-group analysis of Group-A vs. Group-B revealed hinge sizes that were significantly larger in steeper corneas (p < 0.01 and p < 0.05, respectively). However, flap thickness in both groups was unaffected by surgical procedure (p = 0.5).  Statistically significant differences were observed in corneal flap hinge size between right eyes versus left eyes, with a mean of 3.98 ± 0.48 vs. 3.78 ± 0.55 mm (p < 0.001). Mean flap thickness in both eyes did not prove to be statistically significantly different with either surgical technique (90.2 ± 1.68 vs. 90.07 ± 1.44 μm, p = 0.8). Sub-group analysis of Group-A vs. Group-B revealed hinge sizes that were significantly larger in steeper corneas (p < 0.01 and p < 0.05, respectively). However, flap thickness in both groups was unaffected by surgical procedure (p = 0.5).

CONCLUSIONS:

Increasing suction duration increases flap hinge length and stabilizes the flap, especially in steeper corneas.