Management of pellucid marginal corneal degeneration

Topographical and functional analysis of different surgical strategies for advanced pellucid marginal degeneration: A long term follow-up

PurposeTo compare clinical and topographical outcomes of three different surgical strategies for advanced pellucid marginal degeneration (PMD).MethodsRetrospective, interventional case series of 8 advanced PMDs undergoing three different surgical interventions: Sliding Keratoplasty (SK), Sliding Keratoplasty with Relaxing Incision (SKRI), Sector Lamellar Keratoplasty (SLK). Pre-operatively and at 1, 3, 6, 12-month and final follow-up (50.8 ± 20.6 months) post-operatively, we collected: uncorrected and corrected distance visual acuity (UDVA and CDVA), spherical equivalent (SE), refractive astigmatism (RA), corneal Ks, topographical astigmatism (TA) and calculated against-the-rule (ATR) component.ResultsCDVA significantly improved from 6 months after surgery (p = 0.04), while final CDVA was at least 20/40 in 75% of eyes. As desired, surgery led to an overcorrection toward with-the-rule astigmatism at 1-month, which then decreased at 12-month and at final follow-up (p < 0.05). The ATR-component was significantly decreased at 1-month (1.9 ± 1.1 vs. 17.6 ± 6.3 D pre-operatively, p = 0.0015) and remained quite stable over time (4.2 ± 4.2 D at final follow-up). In subgroup analysis, SK and SKRI offered better CDVA and lower RA, while SLK showed more TA stability. The ATR component, comparing baseline and final follow-ups, decreased from 16.8 ± 8.3 D to 5.9 ± 3.6 after SK; from 18.9 ± 3.6 D to 3.3 ± 3.3 D after SKRI; from 17.0 ± 10.3 D to 1.9 ± 1.5 D after SLK.ConclusionThe surgical treatment of advanced PMD showed long-term favourable outcomes. SK and SKRI offered better visual outcomes, but were more inclined to astigmatism regression over time. Conversely, SLK had more stable results but offered worse refractive outcomes.

Scleral lens induced short term corneal changes in eyes with Pellucid Marginal Degeneration

PURPOSE

To investigate the short-term effect of scleral lens (SL) on corneal curvature and corneal oedema in Pellucid Marginal Degeneration (PMD) eyes.

METHODS

Corneal anterior, posterior curvature and corneal thickness were measured in 14 eyes of 14 PMD participants with Schiempflug imaging at different corneal diameters and meridians at baseline and after 6 h of SL wear.

RESULTS

There was a significant flattening (up to 0.26 mm) of the anterior corneal curvature noted in the inferotemporal quadrant (from 210 to 255 degree at 2 mm, 8 mm and 10 mm corneal diameter), inferonasal quadrant (from 285 to 345 degree at 6 mm and 8 mm corneal diameter), and inferiorly at 2 mm and 10 mm corneal diameter (p < 0.05). Similarly, posterior corneal curvature showed statistically significant steepening mostly in inferotemporal quadrants (from 195 to 255 degree from 4 mm to 8 mm corneal diameter) and inferonasally at 2 mm and 4 mm corneal diameter (p < 0.05). A statistically significant increase in the corneal thickness noted in different corneal diameters with corneal oedema ranging from 2.10 % to 4.00 % after 6 h of SL wear. A gradual increase in corneal oedema was noted form centre to periphery. The baseline central fluid reservoir thickness (FRT) was 341.07 ± 139.8 which reduced to 276.71 ± 114.32 µm after 6 h of lens wear. No significant correlation was noted between corneal oedema with different parameters like initial and final FRT, change in anterior and posterior corneal curvature, and lens thickness (p > 0.05).

CONCLUSIONS

Short-term SL wear induced a clinically acceptable range of corneal oedema. A clinically significant flattening in anterior curvature and minimal steepening in posterior curvature were noted. Practitioners should be careful while measuring corneal parameters in PMD eyes wearing SL, as these alterations can provide false impression of disease progression.

Corneal cross-linking in pellucid marginal degeneration: Evaluation after five years

Purpose:

Methods:

Results:

Conclusion:

Between eye asymmetry in keratoconus in an Indian population

PURPOSE

The purpose of this study was to assess the clinical as well as topographic asymmetry between the eyes in keratoconus.

METHODS

Clinical examination including retinoscopy, distant direct ophthalmoscopy, manual keratometry (Bausch & Lomb), slitlamp biomicroscopy and topography (Nidek ARK10000) was carried out on 44 eyes of 22 subjects. At least four high quality topographical images, which were within 0.25 D of one another as measured by simulated keratometry (SimK), were obtained for each eye. Of these, the one with the best alignment and at least six digitised rings was selected for analysis.

RESULTS

The visual acuity (logMAR), and spherical and cylindrical errors showed marked asymmetry with means of 0.3 +/- 0.3 (SD),-5.2 +/- 6.2 D,-3.1 +/- 2.5 D in the better eyes and 0.5 +/- 0.3,-9.8 +/- 8.5 D,-5.0 +/- 2.5 D in the worse eyes (p = 0.01, 0.05, 0.01, respectively). Scissoring retinoscopy reflex, oil droplet sign, Munson's sign, Vogt's striae, scarring and keratometry readings were significantly greater in the more affected eyes. The inferior-superior steepening, central corneal power and apex power as deduced from topography were significantly greater in the more affected eyes with values of 20.3 +/- 15.7 D, 51.4 +/- 10.1 D, 56.7 +/- 11.0 D in the better eyes and 30.4 +/- 18.6 D, 60.1 +/- 10.9 D, 68.7 +/- 19.6 D in the worse eyes (p = 0.05, 0.01, 0.02).

CONCLUSION

Keratoconus is essentially a bilateral but asymmetric corneal degeneration. Seven of our patients had clinically unilateral keratoconus but on topography, based on KISA% index, six of the unaffected eyes were diagnosed as keratoconus though much milder than in the other eye.

Refractive and Corneal Aberrometric Changes After Crescentic Lamellar Wedge Resection in Pellucid Marginal Degeneration

OBJECTIVE

To evaluate the effectiveness of crescentic corneal lamellar wedge resection for the treatment of pellucid marginal degeneration (PMD) in improving refractive, visual, and corneal aberrometry.

METHODS

The study included 10 eyes of 10 patients who had undergone corneal lamellar wedge resection for PMD. Pellucid marginal degeneration was diagnosed based on the clinical signs and corneal topography. The corneal aberrometry was evaluated with Sirius corneal topography.

RESULTS

The mean follow-up period was 14.1 months (range, 9-24 months). Uncorrected visual acuity was improved in nine eyes and remained unchanged in 1 case, whereas best-corrected visual acuity was improved in all eyes postoperatively. By vector analysis, the overall mean astigmatic drift at the last visit was calculated to be 13.0±6.3 diopters (D). At last visit, significant reductions were found for all aberrometric measurements. However, the differences were not significant for the measurements of trefoil (P=0.189).

CONCLUSIONS

Corneal lamellar wedge resection is a favorable surgical option for management of PMD, allowing for improved visual acuity, keratometric cylinder, and corneal aberrations.

Femtosecond laser-assisted cataract surgery in vitrectomized eye with posterior chamber phakic intraocular lens

We describe a case of femtosecond laser-assisted cataract surgery (FLACS) in an eye with multiple comorbidities, including retinal detachment surgery, high myopia, posterior chamber phakic intraocular lens (PC pIOL) and residual, emulsified, silicone oil located in the anterior chamber. FLACS was affected by the optical blockage, but the incomplete capsular tear was recoverable. The case suggests that silicone oil bubbles concentrated at the dome of the posterior corneal surface, along with the PC pIOL optic edges and scars after corneal astigmatic relaxing incisions can lead to incomplete anterior capsulotomy.

Corneal perforation during scleral indentation in a patient with pellucid marginal degeneration

An observational case report of corneal perforation following scleral indentation in a patient with previously undiagnosed pellucid marginal degeneration is presented. Clinical examination, investigations, and subsequent management of this unwarranted and rare complication are described and discussed. The case highlights the need for thorough anterior segment examination before indirect ophthalmoscopy particularly in the presence of ectatic corneal pathology in which case scleral indentation should be avoided.

Corneal Collagen Cross-Linking in Pellucid Marginal Degeneration: 2 Patients, 4 Eyes

Purpose. To report the long-term results of corneal collagen cross-linking (CXL) with riboflavin and ultraviolet-A irradiation in 4 eyes of 2 patients affected by pellucid marginal degeneration (PMD). Methods. This study involved the retrospective analysis of 4 eyes of 2 patients with PMD that underwent CXL treatment. Of the eyes, three had only CXL treatment and one had CXL treatment after an intrastromal corneal ring segment implantation. We have pre- and postoperatively evaluated uncorrected distance visual acuity (UDVA), best corrected distance visual acuity (BCDVA), corneal topography (Pentacam), specular microscopy, and pachymetry. Results. Patient 1 was a woman, aged 35, and Patient 2 was a man, aged 33. The right eye of Patient 1 showed an improvement in her BCDVA, from 16/40 to 18/20 in 15 months, and her left eye improved from 12/20 to 18/20 in 20 months. Patient 2's right eye showed an improvement in his BCDVA, from 18/20 to 20/20 in 43 months, and his left eye improved from 16/20 to 18/20 in 22 months. No complications were recorded during or after the treatment. Conclusion. CXL is a safe tool for the management of PMD, and it can help to stop the progression of this disease.

Scleral Lenses

OBJECTIVE

To present a comprehensive review of current and historical literature on scleral lenses.

METHODS

A comprehensive search of several databases from each database's earliest inception to May 23, 2014 was conducted by an experienced librarian with input from the author to locate articles related to scleral lens design, fabrication, prescription, and management.

RESULTS

A total of 899 references were identified, 184 of which were directly related to scleral lenses. References of interest were organized by date, topic, and study design. Most of articles published before 1983 presented lens design and fabrication techniques or indications for scleral lens therapy. Case reviews published after 1983 identified major indications for scleral lenses (corneal ectasia, ocular surface disease, and refractive error) and visual and functional outcomes of scleral lens wear. Statistically significant improvements in visual acuity, vision-related quality of life, and ocular surface integrity were reported. Reviews of ocular and systemic conditions suggested that comprehensive management strategies for these conditions could include scleral lenses. Early work investigating scleral lens fitting characteristics, optical qualities, and potential physiological impact on anterior ocular structures have been published in the past 5 years.

CONCLUSIONS

Indications for scleral lens wear are well-established. Developing areas of research on the physiologic impact of scleral lens wear on the ocular surface, the use of technology to improve scleral lens vision and fit, and the impact of these devices on the quality of life should further enhance our understanding of scleral lenses in the future.

A single 210-degree arc length intrastromal corneal ring implantation for the management of pellucid marginal corneal degeneration

PURPOSE

To determine the visual and refractive outcomes of 210-degree arc length intrastromal corneal ring segment (ICRS) implantation in eyes with pellucid marginal corneal degeneration (PMCD).

DESIGN

Retrospective, consecutive case series.

METHODS

Sixteen consecutive eyes of 10 patients who underwent a single 210-degree ICRS implantation by femtosecond laser for the management of PMCD and completed at least 1 year follow-up were included. A complete ophthalmic examination was performed preoperatively and postoperatively, including uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest spherical and cylindrical refractions, spherical equivalent, and keratometric readings.

RESULTS

The mean follow-up period was 30.7 months (range 12 to 36 months). No intraoperative complication was observed. White deposits around the segments were noted in 2 of 16 eyes (12.5%) at the first postoperative year. The mean UCVA showed significant improvement, from 1.69 +/- 1.02 logarithm of the minimal angle of resolution (logMAR) preoperatively to 0.64 +/- 0.43 logMAR at the 36th month (n = 11, P < .001). The mean preoperative BSCVA was 0.88 +/- 0.68 logMAR; after 36 months, this improved to 0.35 +/- 0.34 (P < .001). At the 36th month, UCVA was improved in all eyes (n = 11, range: gain of 1 to 6 lines), whereas BSCVA was improved in 9 eyes (81.8%, range: gain of 2 to 7 lines) and remained unchanged in 2 eyes (18.1%); UCVA was 20/40 or better in 3 eyes (27%) and BSCVA was 20/40 or better in 8 eyes (72.7%). There was a significant reduction in the spherical equivalent refractive error, from -4.40 +/- 1.85 diopters (D) preoperatively to -1.86 +/- 0.60 D (P < .001), and the mean maximum keratometric power decreased from 49.70 +/- 4.32 D to 46.08 +/- 2.84 D (P < .001) after 36 months. The mean cylindrical refraction decreased from -4.39 +/- 1.86 D preoperatively to -2.38 +/- 1.35 D at 36 months (P < .001).

CONCLUSION

A single 210-degree arc length ICRS implantation using a femtosecond laser for patients with PMCD provides good visual and refractive outcomes.

Pellucid marginal corneal degeneration: evaluation of the corneal surface and contact lens fitting

AIM

To quantify corneal irregularities, to describe the fitting with contact lenses, and to answer the question whether or not contact lenses with a special back surface design could improve visual acuity in patients with pellucid marginal corneal degeneration (PMCD).

METHODS

13 eyes were fitted with contact lenses with a special back surface. Videokeratographic data were assessed. The patients were followed up for an average period of 22.2 months. Lens tolerance and corrected visual acuity were evaluated.

RESULTS

The mean eccentricity did not exceed 0.7 in all patients. Either the superior or the inferior eccentricity, or both, were negative in all patients. Using Fourier analysis all PMCD subjects showed an increased irregular astigmatism of the anterior cornea. Using Zernike coefficients seven eyes (53.8%) had a higher order aberration root mean square error (HOA RMS error) out of the normal range. The visual acuity with contact lenses improved in all eyes with an average increase of 2.7 lines (maximum eight lines). No serious complications were observed.

CONCLUSIONS

Quantitative evaluation of videokeratographic data may help to diagnose PMCD and to distinguish PMCD from other ectatic corneal diseases. Contact lenses with a special back surface design can improve visual acuity and lens tolerance.

Bitoric Gas-Permeable Contact Lens Application in Pellucid Marginal Corneal Degeneration

PURPOSE

To evaluate the authors' experience fitting patients with pellucid marginal corneal degeneration (PMCD) with bitoric gas-permeable contact lenses.

METHODS

The records of 11 patients with a confirmed diagnosis of PMCD were retrospectively reviewed. The numbers of diagnostic contact lenses at the first visit, office visits, and lenses ordered to complete the fitting; uncorrected, spectacle-corrected, and contact lens-corrected Snellen visual acuities; contact lens success or failure; and complications encountered were all assessed. These data were compared to historic data for patients with other corneal irregularities (keratoconus, penetrating keratoplasty, and refractive surgery).

RESULTS

The mean number of diagnostic contact lenses used at the first visit was 1.09 +/- 0.302, and the number of lenses ordered to complete the fitting was 1.82 +/- 1.33. The number of visits during 4 months was 6.18 +/- 2.14. Uncorrected visual acuity (logMAR) was 0.957 +/- 0.398 (20/181 in Snellen); the best-corrected spectacle visual acuity (logMAR) was 0.231 +/- 0.309 (20/34 in Snellen); and the best contact lens-corrected visual acuity (logMAR) was 0.0424 +/- 0.06275 (20/22 in Snellen). Corrected vision in eyes with PMCD improved approximately two lines with bitoric gas-permeable contact lenses compared to that achieved with spectacles. Ten (91) of the patients met the criteria of contact lens success during the 4-month follow-up period.

CONCLUSIONS

Bitoric gas-permeable contact lenses achieved a comfortable and visually successful fit in most eyes with PMCD. Patients with PMCD used the fewest contact lenses and had the fewest lens exchanges, but required more office visits than other groups of patients with various corneal irregularities.

Management of Pellucid Marginal Corneal Degeneration

PURPOSE

This study was designed to determine how patients with pellucid marginal corneal degeneration (PMCD) are managed in a tertiary corneal practice.

METHODS

A retrospective chart review of 45 patients with PMCD from a corneal referral practice was performed. Information collected from the medical records included demographic data, best-corrected visual acuity, videokeratography, contact lens use, and surgical procedures.

RESULTS

Forty-five patients (85 eyes; 30 males, 15 females) with PMCD were included in this study. They were followed-up for an average of 4.7 years (standard deviation (SD), +/-8.7). Seventy-five eyes (88.2%) were managed nonsurgically with spectacles in 31 eyes (36.4%) or contact lenses in 44 eyes (51.8%). Contact lens management was initially attempted in 51 eyes (60%); however, 7 eyes failed contact lenses. Visual acuity of 0.5 (20/40) or better was noted in 34 eyes (75.5%) after contact lens fit. Ten eyes (11.8%) underwent penetrating keratoplasty with an average postoperative follow-up of 9 years (SD, +/-8.2; 1.5-20.5). Clear grafts were present in all 10 eyes at the end of the study (average, 9 years; SD, +/-82).

CONCLUSIONS

Nonsurgical management of PMCD continues to play a predominant role in the management of this disorder. Poor best-corrected visual acuity at presentation of 0.2 (20/100) or worse and long follow-up (8 years or more) were significantly associated with surgery.

Reverse-Geometry Gas-Permeable Lens Design for Pellucid Marginal Degeneration

PURPOSE

To report a case of treating a patient with pellucid marginal degeneration (PMD) by using a reverse-geometry gas-permeable lens design.

METHODS

A 38-year-old Hispanic man was referred for having reduced visual acuity secondary to distorted corneas. The patient was diagnosed with PMD after an extensive slitlamp examination showed a thinning of the inferior peripheral cornea in both eyes. Corneal topography (Orbscan II) was performed to help confirm the diagnosis. A Reverse Aspheric Ortho Focus (RAOF) gas-permeable lens was fitted on this patient.

RESULTS

The Orbscan II corneal topography showed distinct peripheral steepening, a pronounced astigmatic pattern (greater in the left eye than in the right), and thinner corneas in the inferior periphery than centrally. The fluorescein pattern of the RAOF 5 lenses showed central alignment, good edge lift 360 degrees, mid peripheral bearing with 0.5 mm vertical movement on blinking, and good centration. The patient's distance visual acuity with the lenses was 20/20-1 in the right eye and 20/20 in the left.

CONCLUSIONS

The Orbscan II was an important tool in making the diagnosis of early PMD, because few clinical signs were observed. Not only does the Orbscan II provide the clinician with a topographic map of the cornea, but it also measures the corneal thickness, which aided in the diagnosis of this patient. In addition, the posterior float measurement provided by the Orbscan II may be instrumental in making a differential diagnosis. A reverse-geometry gas-permeable lens provided the patient with improved peripheral fit over conventional designs, adequate comfort, and optimal visual acuity.

Implantation of a toric phakic intraocular lens to correct high corneal astigmatism in a patient with bilateral marginal corneal degeneration

We present a patient with marginal corneal degeneration and corneal astigmatism of more than 10.0 diopters (D). A toric phakic intraocular lens (IOL) of 7.0 D cylindrical power was implanted in both eyes to correct the high astigmatism. An uncorrected visual acuity of 20/40 was achieved in both eyes, and the best corrected visual acuity improved by 4 Snellen lines to 20/20 in both eyes. Refraction and visual acuity remained stable at 1.5 years postoperatively. Implantation of a toric phakic IOL can be an option to correct high corneal astigmatism even when the full corneal astigmatism cannot be treated.

Intacs for early pellucid marginal degeneration

A 42-year-old man had Intacs (Addition Technology Inc.) implantation for early pellucid marginal degeneration (PMD). Two Intacs segments (0.45 mm thickness) were inserted uneventfully in the fashion typically used for low myopia correction (nasal-temporal). Eleven months after the procedure, the uncorrected visual acuity was 20/200, compared with counting fingers preoperatively, while the best spectacle-corrected visual acuity improved to 20/25 from 20/50. Corneal topographic pattern also improved. Although the results are encouraging, concern still exists regarding the long-term effect of this approach for the management of patients with PMD.

Nomogram for spherical RGP contact lens fitting in patients with pellucid marginal corneal degeneration (PMCD)

PURPOSE

To present a nomogram for spherical rigid gas-permeable (RGP) contact lens fitting in patients with pellucid marginal corneal degeneration (PMCD).

METHODS

Retrospective review of the medical records of 24 patients diagnosed with PMCD who underwent an RGP contact lens trial at the Bausch & Lomb contact lens center between April 1995 and March 2002 at L.V. Prasad Eye Institute in Hyderabad, India. Data collected included age and sex of patients, duration of presenting symptoms, associated ocular conditions, presenting visual acuity, and degree of astigmatism. For the purpose of analysis, the astigmatism was classified into four groups: group 1, less than 5.00 diopters (D); group 2, 5.00 to 10.00D; group 3, 10.00 to 15.00D; and group 4, 15.00 to 20.00D. The final lens parameters, the patient's comfort level, and the duration of follow-up were analyzed.

RESULTS

Forty eyes of 24 patients were fitted with RGP contact lenses during the study period. Sixteen were male patients and eight were female patients. The age of the patients ranged from 13 to 59 years, with a mean of 35.5 years. Twenty-two (91.7%) patients had typical inferior PMCD, whereas the other two (8.3%) had superior PMCD. The mean corneal curvature was 7.1 mm (range, 5.9-7.8 mm) in group 1, 6.9 mm (range, 6.6-7.9 mm) in group 2, 7.5 mm (range, 6.5-7.8 mm) in group 3, and 7.9 mm (range, 6.8-7.8 mm) in group 4. The mean base curve of the final fitting lens was 6.3 mm (range, 5.7-7.8 mm) in group 1, 6.8 mm (range, 5.9-7.8 mm) in group 2, 7.5 mm (range, 6-8.2 mm) in group 3, and 7.2 mm (range, 6.6-7.8 mm) in group 4. The mean lens diameter of the final fitting lens was 8.7 mm (range, 8.6-10.6 mm) in group 1, 9.5 mm (range, 8.8-10.5 mm) in group 2, 10.2 mm (range, 8.8-11.5 mm) in group 3, and 10.4 mm (range, 8.8-11.3 mm) in group 4. The common fluorescein patterns were central touch with midcentral peripheral pooling in 14 (35%) and dumbbell pattern in seven (17.%). The final visual acuity range with an RGP lens in the four astigmatism groups was 20/40 to 20/20 in group 1, 20/30 to 20/20 in group 2, 20/40 to 20/20 in group 3, and 20/200 to 20/50 in group 4. Twenty-one patients were comfortable with an RGP lens, and the mean duration of follow-up was 13 months. Three patients discontinued lens wear. In one patient, the lens was not stable, and the other two experienced discomfort with their lenses.

CONCLUSIONS

Spherical rigid gas-permeable lenses are a good option for patients even with advanced PMCD. In patients with astigmatism of less than 10D, a lens with a base curve of 6.0 to 7.0 mm and a diameter of 8.0 to 9.5 mm seems to be a good initial lens for trial, and for patients with astigmatism of more than 10D, a lens with a base curve of 7.0 to 7.5 mm and a diameter of 10.0 to 10.5 mm seems to be a good initial lens.

Between-eye asymmetry in keratoconus

PURPOSE

To report baseline differences between eyes on key variables in the Collaborative Longitudinal Evaluation of Keratoconus (CLEK) Study cohort compared with a retrospectively assembled group of myopic contact lens wearers without ocular disease.

METHODS

A total of 1,079 keratoconus patients who had not undergone a penetrating keratoplasty in either eye before their baseline visit were enrolled and examined at baseline. Records from 330 contact lens-wearing myopes were reviewed. Corneal curvature (keratometry), visual acuity, refractive error (manifest refraction), and corneal scarring were measured.

RESULTS

The mean differences between keratoconic eyes are as follows (better eye-worse eye for each variable, separately). Flat keratometry: -3.59 +/-4.46 D and steep keratometry: -4.35 +/-4.41 D; high-contrast best-corrected visual acuity: 7.30 +/-6.83 letters; low-contrast best-corrected visual acuity: 8.53 +/-7.51 letters; high-contrast entrance visual acuity: 9.03 +/-8.40 letters; low-contrast entrance visual acuity: 9.43 +/-7.88 letters; spherical equivalent refractive error: 3.15 +/-3.84 D; and refractive cylinder power 1.55 +/-1.42 D. Twenty-one percent of the keratoconus patients had corneal scarring in only one eye. There is an association between patient-reported unilateral eye rubbing and greater asymmetry in corneal curvature, and between a history of unilateral eye trauma and greater asymmetry in corneal curvature and refractive error, with the rubbed/traumatized eye being the steeper eye most of the time.

CONCLUSIONS

Keratoconus is asymmetric in the CLEK Study sample.