Corneal Degeneration Research Articles

Dégénérescence marginale pellucide compliquée d’un hydrops cornéen aigu spontané

Pellucid marginal corneal degeneration (PMCD) is an ectatic corneal disorder characterized by a peripheral, noninflammatory band of thinning of the inferior cornea. This condition often is misdiagnosed with keratoconus, with which it shares several clinical, videotopographic, and histologic aspects. Furthermore, as with keratoconus, hydrops and spontaneous corneal perforation can occur. We report the case of a 56-year-old man with confirmed PMCD, emphasizing the diagnostic approach, the disease follow-up, and its complication in spontaneous acute corneal hydrops. Finally, regarding this case, authors collect the clinical and videotopographic characteristics of PMCD and discuss the different therapeutic options.

Reduction of Hyperopia and Astigmatism After Superficial Keratectomy of Peripheral Hypertrophic Subepithelial Corneal Degeneration

To report the development of progressive hyperopia and astigmatism resulting from peripheral hypertrophic subepithelial degeneration which was treated with superficial keratectomy of the lesion. Case report. A patient with peripheral hypertrophic subepithelial degeneration of both corneas was followed up for a 6-year period. During this time, the patient experienced a slowly progressive increase in hyperopia and astigmatism in both eyes. In the left eye, extension of the degeneration paracentrally resulted in significant hyperopia and astigmatism and a best spectacle-corrected visual acuity of 20/70. Superficial keratectomy was performed and resulted in a dramatic reversal of the hyperopic and astigmatic shift and a best spectacle-corrected visual acuity of 20/30. Peripheral hypertrophic subepithelial corneal degeneration can result in progressive flattening of the central corneal topography in the involved meridians. This flattening can induce a significant hyperopic and astigmatic shift in refraction. This refractive change can be reversed with superficial keratectomy to remove the degeneration.

Management of Superior Pellucid Marginal Degeneration With a Single Intracorneal Ring Segment Using Femtosecond Laser

A 26-year-old man with superior pellucid marginal corneal degeneration associated with poor visual acuity due to irregular astigmatism was treated with single-segment intracorneal ring insertion. Preoperatively the patient's uncorrected visual acuity (UCVA) was 0.05, best spectacle-corrected visual acuity (BSCVA) was 0.15, and manifest refraction was -4.50 x 85 in the left eye. The flattest meridian (K1) measured was 38.50 x 90 and the steepest meridian (K2) was 51.10 x 30. Three months postoperatively, UCVA was 0.15, BSCVA was 0.4, and manifest refraction was -2.50 x 90. The use of single Intacs with femtosecond laser to treat superior pellucid marginal corneal degeneration improved visual acuity.

Salzmann's Nodular Corneal Degeneration Clinical Characteristics and Surgical Outcomes

To characterize the clinical characteristics and surgical outcomes for Salzmann's nodular corneal degeneration (SNCD). In this retrospective, noncomparative, observational case series, all patients coded with a diagnosis of SNCD between January 1, 1996, and April 30, 2002 were included. Cases whose clinical description did not match the classic description of this disorder were excluded. Clinical characteristics, surgical procedures, and qualitative outcomes were recorded. Among 103 patients diagnosed with SNCD, 93 (152 eyes) met inclusion criteria. Eighty-three patients (89.2%) were women (P < 0.00001), and 59 patients (63.4%) had bilateral disease. A normal age distribution was noted, with a mean age of 54.3 years (median, 53 years; standard deviation = 16.9). Meibomian gland dysfunction was noted in 51 patients (54.8%), contact lens wear in 31 patients (33.3%), peripheral vascularization in 29 patients (31.2%), pterygium in 15 patients (16.1%), keratoconjunctivitis sicca in 9 patients (9.7%), and exposure keratitis in 4 patients (4.3%). Forty-nine eyes (32.2%) of 37 patients (39.8%) required a total of 62 surgical procedures. Impaired vision led to 53 (85.5%) of these procedures and resulted in improved vision in 42 (79.2%) of these cases. Seven eyes (4.6%) underwent surgical intervention for subjective discomfort or contact lens intolerance, and all had improved symptoms at last follow-up. SNCD appears to be a disorder that occurs predominantly in middle-aged women and may be associated with chronic ocular surface inflammation and/or irritation. It is important to diagnose properly because of the good prognosis with medical and surgical therapy.

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

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

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

IS TAMOXIFEN A RISK FACTOR FOR RETINAL VASO-OCCLUSIVE DISEASE?

Brief Reports SD, 32.7 ⫾ 4.92 years). All patients had no history of glaucoma or ocular hypertension before silicone oil tamponade. Ocular hypertension was defined as in- traocular pressure (IOP) of ⱖ21 mmHg. Sixteen pa- tients were aphakic, and three patients had compli- cated cataract. The predisposing diseases (reasons for silicone oil tamponade) were traumatic proliferative vitreoretinopathy in 17 cases and rhegmatogenous ret- inal detachment in 2 cases. Acri-Sil-ol 5000 (Acri-tec, Germany) with high viscosity was used for silicone oil tamponade. TREATMENT OF GLAUCOMA SECONDARY TO SILICONE OIL RETENTION X.F. LIN, MD, L.Y. LIANG, M.K. LIN, MD, Z.H. YUAN From Zhongshan Ophthalmic Center, Guangzhou, Guangdong Province, China. Nineteen eyes with secondary glaucoma due to sili- cone oil retention after silicone oil removal are de- scribed. The mean intraocular pressure ⫾ SD was 37.23 ⫾ 6.47 mmHg 7.89 ⫾ 2.75 days after silicone oil removal. In 5 eyes, medical therapy was effective to control intraocular pressure, while the other 14 eyes needed surgery. Cibis was the first to adopt silicone oil in the treat- ment of retinal detachment in 1962. With the rapid development of complicated posterior segment surger- ies, the use of silicone oil has increased, thus greatly improving the prognosis of proliferative vitreoreti- nopathy. However, silicone oil–related complications have also appeared. For example, retention of silicone oil after its removal may lead to secondary glaucoma, which is often overlooked and leads to the adverse consequence of delaying treatment. To study clinical features and to evaluate therapeutic efficacy, we re- viewed 19 cases (19 eyes) of secondary glaucoma due to silicone oil retention after silicone oil removal that occurred from February 2001 to May 2003. General Conditions Silicone oil removal was performed 2 months to 2.3 years (mean ⫾ SD, 17.25 ⫾ 3.16 months) after sili- cone oil tamponade. Indications for silicone oil re- moval were silicone oil emulsification (in the vitreous and anterior chamber) in 9 eyes, secondary glaucoma in 7 eyes (combined with silicone oil emulsification in 5 eyes [emulsification was detected before silicone oil removal in 3, but it was discovered during silicone oil removal in 2]), and band-shaped corneal degeneration in 4 eyes. In two cases, silicone oil removal was performed ⬎1 year after silicone oil tamponade as a result of the patients’ wishes, although no symptoms were identified. In all cases, silicone oil removal was performed via a pars plana entry. First, an infusion cannula was inserted into the vitreous cavity from an incision at the inferotemporal quarter 4.0 mm away from the limbus. Then another pars plana incision of 1.5 mm in length was made at the superotemporal quarter 4.0 mm away from the limbus. Depressing the posterior margin of the incision facilitated the silicone oil outflow. Silicone oil removal and pars plana lensectomy were done simultaneously on one eye with severe complicated cataract and silicone oil in the anterior chamber. Meanwhile, in the eyes with apha- kia and in the eye that underwent silicone oil removal and pars plana lensectomy, the contents of the anterior chamber were also replaced with balanced salt solu- tion. In the other two cases, no additional efforts were made to replace the aqueous humor, because no ob- Patients and Methods Patients Of 19 patients, 17 were males and 2 were females; their ages ranged from 15 to 47 years (mean age ⫾ The authors have no financial or proprietary interest in the study. Reprint requests: Dr. X.F. Lin, Zhongshan Ophthalmic Center, Xian Lie Nan Road 54, Guangzhou, Guangdong Province, China 510060; e-mail: Dragonye2002@yahoo.com.cn RETINA ® , The Journal of Retinal and Vitreous Diseases, encourages authors to submit Brief Reports describing unusual findings, new techniques, and new instruments. Material submitted for consideration in this section of the journal is done so with the assumption that the data provided do not duplicate previously published material and that the material has not been submitted for consideration elsewhere. Each author must sign a disclosure to this effect (see Instructions to Authors for complete wording of transfer letter). Brief Reports submitted for this section of the journal may be subjected to the standard review process that is applied to other material submitted to RETINA ® . Brief Reports should follow the requirements listed in the Instructions to Authors, with the following caveats: Brief Reports should not exceed 4 pages in length; no more than 5 references should be cited; and each Brief Report should include no more than 4 figures.

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.

In vivo confocal microscopy of megalocornea with central mosaic dystrophy

In vivo confocal microscopy was performed on the central cornea of both eyes of a patient with megalocornea and central mosaic dystrophy. In the stroma, starting just below Bowman's membrane, polygonal, moderately reflective areas of opacification separated by diagonal hyporeflective striations were observed. The opaque areas appeared smaller in the anterior stromal layers and seemed to get larger towards the posterior stroma. The epithelium, Bowman's membrane and endothelium appeared normal. In vivo confocal microscopy is helpful in evaluating the morphological characteristics of corneal dystrophies, degenerations or developmental abnormalities of the cornea, and may prove to be helpful in understanding their pathophysiology.

Compressive C-shaped lamellar keratoplasty: A surgical alternative for the management of severe astigmatism from peripheral corneal degeneration

To describe a compressive lamellar surgical technique for treating severe astigmatism in peripheral corneal ectasia. Retrospective, noncomparative, interventional case series. Four eyes of 3 patients with either pellucid or Terrien's marginal corneal degeneration were included in this series. C-shaped lamellar keratoplasty using multiple trephines of different sizes, with deliberate undersizing of the donor graft for a controlled compressive effect, was performed on these patients. Visual acuity outcome and refraction were measured at different intervals at up to 40 months of follow-up. All eyes achieved Snellen visual acuity of 20/40 or better and stable astigmatism ranging from 0 to -2.75 diopter cylinder within 6 months, with no recurrence of corneal thinning or peripheral corneal vascularization. Compressive C-shaped lamellar keratoplasty is able to reduce severe corneal astigmatism in peripheral corneal ectasia and can result in good visual and refractive outcomes with early visual rehabilitation.

Quantitative Evaluierung topographischer Parameter zur Differenzierung von Keratokonus und pelluzidaler marginaler Hornhautdegeneration

The purpose is to compare videokeratometric data (Fourier series harmonic analysis and wave-front analysis) in eyes with ectatic corneal disease (keratoconus; pellucid marginal corneal degeneration [PMCD]) and to determine parameters for early diagnosis and distinction of keratoconus and PMCD. 13 eyes with PMCD, 32 eyes with keratoconus and 18 healthy eyes were included. Computerized videokeratographic methods were assessed, using Fourier series harmonic analysis, Zernike coefficients and eccentricity. Irregular astigmatism (Fourier series harmonic analysis: decentration and/or irregularity) and the aberration coefficient were out of the normal range in all pathologic eyes. Both the nasal and the temporal eccentricities were greater than 0.63 in all PMCD patients, whereas either the superior or the inferior eccentricity was negative in all patients. In keraotoconic eyes, all quadrant eccentricities were positive and greater than 0.4. Irregular astigmatism and the aberration coefficient are useful parameters in detecting ectatic corneal disease using a computerized videokeratoscope. The calculation of the spherical equivalent (Fourier series harmonic analysis: no decrease of spherical equivalent in PMCD subjects) and of quadrant eccentricities are useful tools in distinguishing PMCD and keratoconus.

Corneal dystrophies and degenerations: a molecular genetics approach

The largest contribution to the refractive power of the eye does not come from the lens, but from the cornea. Opacity of this part of the eye is one of the most important causes of visual impairment. The book edited by Dr Wang is a largely successful attempt to give a summary of a group of inherited diseases affecting the cornea. The aim of the volume is to educate the reader about all aspects of these diseases from the elucidation of the molecular pathogenesis to the current therapeutical options. In the preface, it is explicitly stated that the practicing ophthalmologist is addressed by the book. Does it succeed in informing 'the' ophthalmologist about genetic issues, and is it also of interest for 'the' geneticist? The material is organized in six chapters: The first chapter gives a summary of the genes known to be mutated in several inherited corneal dystrophies. The chapter focuses on the gene encoding keratoepithelin (TGFBI, BIGH3), in which mutations have been identified in at least six clinically distinct inherited corneal dystrophies, and it also contains information about dystrophies not linked to the TGFBI gene on chromosome 5q. Very useful in this chapter are the tables listing the corneal dystrophies and their mode of inheritance, the mutations in the TGFBI gene (with information on genotype-phenotype correlation), and the corneal dystrophies not linked to the TGFBI gene. Chapters 2–4 review the corneal dystrophies of the corneal epithelium and Bowman's layer, corneal stroma, and corneal endothelium, respectively. The organization of the material about the diseases is somewhat different between the different chapters, but by and large there is a paragraph on the clinical picture, on the histopathology, on genetics and disease mechanisms, and on therapeutical options and patient management for the described corneal dystrophies. Chapter 5 gives an overview about corneal and conjunctival degenerations, most of which are not inherited, but have an exogenous cause. Chapter 6 summarizes the use of excimer laser surgery in treating corneal dystrophies. The book also contains questions for self-study examination, and a detailed and very useful index. Also included is a CD with all figures of the book plus several additional figures.

Ferrara intracorneal ring implantation and cataract surgery for the correction of pellucid marginal corneal degeneration

We report a case of Ferrara intracorneal ring (Mediphacos) implantation and cataract surgery for the correction of pellucid marginal corneal degeneration. Preoperatively, the patient's uncorrected visual acuity (UCVA) was 0.05 in the right eye and 0.10 in the left eye. The best spectacle-corrected visual acuity (BSCVA) was 0.50 with −2.00 −11.25 × 80 in the right eye and 0.60 with −2.00 −5.50 × 95 in the left eye. One month postoperatively, the UCVA was 0.50 in the right eye and 0.30 in the left eye. The BSCVA was 0.80 with −1.00 in the right eye and 0.60 with −0.75 −1.25 × 160 in the left eye. Ferrara intrastromal rings and cataract surgery resulted in a more regular corneal shape with a reduction in astigmatism for good visual recovery.

Kératocône : que deviennent les patients âgés ?

Keratoconus is a degenerative corneal disease that is most often seen in young patients. The object of the present study was to analyze the demography of keratoconus patients. We conducted a prospective study at Bordeaux University Hospital from January 2001 to September 2001. The study included all the consecutive patients with a diagnosis of keratoconus, detected previously or during the current examination. Inclusion criteria included evidence of unilateral or bilateral abnormal corneal steepening with videotopography. We included 121 patients. The results showed a mean age of 33.4 years in males and 37.1 years in females. The number of patients older than 50 was low: 3 out of 83 (3.6%) males and 6 out of 38 (15.7%) females. Two hypotheses on the low number of older patients can be suggested. 1) Keratoconus, which is a collagen disorder of the corneal stroma, may be associated with other undetected systemic diseases, which could induce premature death. Different studies have suggested a relationship between keratoconus and mitral valve prolapse. In this case, we can propose preventive treatment. 2) These patients, who have been informed of the nature and the therapeutical modalities of their disease, no longer consult at the hospital, but are followed by their local ophthalmologists.

Changing indications for corneal transplantation at the King Khaled Eye Specialist Hospital (1983-2002).

To identify changing indications for keratoplasty over the last 20 years at a tertiary care eye hospital in a country with rapidly evolving ophthalmic care services. A retrospective review was performed of the eye bank records of every patient who received a lamellar or penetrating keratoplasty at the King Khaled Eye Specialist Hospital in Riyadh, Saudi Arabia, between January 1, 1983 and December 31, 2002. For each case, the primary surgical indication was identified. A total of 8318 corneal transplants were performed during this 20-year period. In the first 5 years of the study, the leading indications for corneal transplantation were corneal scarring (52.0%), aphakic/pseudophakic bullous keratopathy (13.5%), corneal degeneration (10.0%), and keratoconus (7.6%). During the last 5 years of the study, the leading indications for corneal transplantation were keratoconus (40.2%), corneal scarring (19.8%), failed corneal transplant (11.3%), and corneal ulceration (10.2%). There was a dramatic increase in the number of transplants performed for keratoconus (441%) and failed corneal transplants (285%) as well as a dramatic decrease in the number of transplants performed for corneal degeneration (-88%) and scarring (-60%) between the first and last 5 years of the study period. Major changes in the indications for corneal transplantation were related to the introduction and expansion of modern ophthalmic services at a time of rapid socioeconomic development and population growth.

Pellucid marginal corneal degeneration

Objective To report the clinical features and outcome of patients with pellucid marginal corneal degeneration (PMCD). Design Retrospective noncomparative case series. Methods Retrospective chart review of 116 eyes of 58 patients with PMCD seen between 1990 and 2002 at the Cornea Service at L.V. Prasad Eye Institute, Hyderabad, India. The diagnosis of PMCD was based on the presence of corneal thinning with ectasia of the normal cornea above or below the area of thinning with no evidence of scarring, vascularization, or lipid deposition and typical topographic features whenever topography was performed. A detailed history including the age of presentation, onset of symptoms, systemic diseases, atopy, and relevant family history was reviewed. The visual acuity (VA) at presentation; the location, extent, and degree of thinning; presence of concurrent keratoconus and keratoglobus; and complications, if any, were noted. The mode of visual rehabilitation; surgical procedure, if any; and the final VA achieved were analyzed. Main outcome measures Clinical features, associations, complications, and outcome of treatment. Results There were 45 males (77.6%) and 13 females (22.4%). All cases were bilateral. In one eye, no clinical features of PMCD were seen, but the diagnosis was made based on topographic features of typical PMCD. The age of the patients ranged from 8 to 66 years, with a mean of 34.0±14.8. One patient (1.7%) had associated vernal keratoconjunctivitis (VKC), 1 (1.7%) had Marfan's syndrome, and 1 (1.7%) had ocular hypertension. The degree of astigmatism was <5.0 diopters (D) in 19 eyes (19.2%), 5 to 10 D in 36 (36.4%), 10 to 15 D in 23 (23.2%), 15 to 20 D in 15 (15.2%), and >20 D in 6 (6.1%). Typical inferior PMCD was seen in 99 eyes (85.3%), and superior PMCD was seen in 17 (14.7%). The thinning was commonly seen between the 5-o'clock and 7-o'clock positions. In 12 eyes (10.3%), PMCD was associated with keratoconus, and in 15 eyes (12.9%), keratoglobus was associated. Seven eyes (6.0%) had hydrops. Visual acuity improved in 52 eyes (55.3%) with correction, in 40 eyes (42.6%) it remained the same as that of the initial presentation, and in 2 eyes (2.1%) it worsened relative to the initial presentation. Forty-one eyes (35.3%) received spectacles, and 31 eyes (26.7%) were fitted with rigid gas-permeable contact lenses. Five eyes (4.3%) underwent surgery. Lamellar keratoplasty was performed in 3 eyes, and a crescentic lamellar graft was done in 2 eyes. Visual acuity improved in 4 eyes after surgery with a follow-up of 2 to 37 months. The final astigmatism in the operated eyes at the last follow-up ranged from 4 to 11 D. Conclusions Pellucid marginal corneal degeneration was seen predominantly in males in this series, and was not strongly associated with VKC. Keratoconus was seen in approximately 10% of the eyes, and keratoglobus in approximately 13%. Superior PMCD was seen in approximately 15% of the eyes. In our study, patients presented with severe astigmatism, and hydrops was a common complication. The majority of patients were treated with spectacles or contact lens. Surgery for PMCD—lamellar keratoplasty and crescentic lamellar keratoplasty, if indicated—usually results in significant residual astigmatism.

Superior pellucid marginal corneal degeneration

To report the clinical features and topographic findings of superior pellucid marginal corneal degeneration (PMCD). Retrospective chart review of 15 eyes of eight patients of superior PMCD. Detailed history, visual acuity at presentation, degree of astigmatism, slit-lamp examination findings, topographic features, and Orbscan findings were noted where available. Improvement in visual acuity with spectacles or contact lens correction, surgical procedure if any, and final visual acuity were analysed. In all, six patients were males and two were females. All cases except one were bilateral. The patients ranged in age from 18 to 48 years. All cases had isolated superior PMCD. One patient was a diagnosed case of vernal keratoconjunctivitis. The visual acuity at presentation ranged from hand motions to 20/25. The degree of thinning varied from 30 to 90%. The extent of thinning was commonly seen between the 10 and 2 o'clock positions. Ectasia was seen below the site of thinning in all the cases of superior PMCD. Topographic features including vertical corridor of reduced power, against-the-rule astigmatism and superior loop cylinder were seen in 10 eyes. Orbscan was carried out in two eyes of one patient and revealed an area of increased elevation in relation to the best-fit sphere superiorly corresponding to the area of ectasia in both the eyes. The visual acuity improved with rigid gas-permeable contact lens in six eyes and the final visual acuity ranged from 20/400 to 20/30. Two eyes were subjected to surgical intervention (peripheral annular graft=1 and lamellar graft=1). PMCD can occur superiorly. It should be considered in the differential diagnosis of superior ectatic disorders. The topographic findings, of reduced power in the vertical meridian and superior loop cylinder, are typical of superior pellucid marginal degeneration. Visual rehabilitation is usually possible with contact lenses, with surgical management required in selected cases.

Lamellar crescentic resection for pellucid marginal corneal degeneration.

To evaluate the results of lamellar crescentic resection in pellucid marginal corneal degeneration. Patients with pellucid marginal corneal degeneration who underwent lamellar crescentic resection from 1995 to 2000 at Labbafinejad Medical Center were assessed. Diagnosis was based on clinical findings of slit-lamp microscopy and confirmed by corneal topography and pachymetry. Fifteen eyes of nine patients (six male and three female) were operated. Mean patient age was 32 years (range 25 to 41 yr). Preoperatively, best spectacle-corrected visual acuity was 20/200 to 20/500 with a range of 12 to 26 D of against-the-rule astigmatism (mean 19.00 D). Follow-up ranged from 13 to 57 months (mean 35 mo). Postoperatively, patients had with-the-rule astigmatism: mean 16.00 D at 6 weeks and 10.50 D at 6 months. In the second postoperative year, mean with-the-rule astigmatism was 4.30 D. Best spectacle-corrected visual acuity was 20/40 in 71% of eyes at final follow-up. No significant complications occurred during the study period. Lamellar crescentic resection was a safe and effective non-penetrating surgical method to manage pellucid marginal corneal degeneration, however, visual recovery was relatively prolonged.

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.

Neurotrophic keratitis.

Neurotrophic keratopathy is a degenerative corneal disease induced by an impairment of trigeminal nerve. Impairment of loss of corneal sensory innervation is responsible for corneal epithelial defects, ulcer, and perforation. In the present report, we reviewed the pathogenesis, diagnosis, and therapeutic aspects of this disease. An accurate history and clinical examination, including the function of cranial nerves, together with the clinical features of the ocular surface are essential for a prompt diagnosis. The evaluation of the corneal sensitivity and tear film function are important diagnostic steps as well. Specific medical and surgical treatments, based on the clinical staging of the disease, are often able to halt its progression. Future developments in the medical treatment including the administration of neuropeptide and growth factors are presented.