Indian Journal of Ophthalmology

ORIGINAL ARTICLE
Year
: 1998  |  Volume : 46  |  Issue : 3  |  Page : 145--147

Central corneal endothelial guttae and age-related macular degeneration : is there an association?


GP Rao, SB Kaye, A Agius-Fernandez 
 St Paul's Eye Unit, Royal Liverpool University Hospital, United Kingdom

Correspondence Address:
G P Rao
St Paul«SQ»s Eye Unit, Royal Liverpool University Hospital, United Kingdom

Abstract

The similarities between the corneal endothelium and retinal pigment epithelium in terms of their embryology, barrier function and predilection to age-related degeneration prompted this investigation into a possible association between central corneal guttae (CCG) and age-related macular degeneration (ARMD). 50 patients with clinically significant CCG were prospectively evaluated for the presence of ARMD. 51 age-matched patients attending for unrelated ailments who did not have CCG were also evaluated for the presence of drusen and other signs of ARMD. Of the 50 patients with CCG, 23 had bilateral ARMD and 4 had unilateral ARMD. In the control group, 9 patients had bilateral and 4 had unilateral ARMD. There was significant difference in the prevalence of ARMD between patients with CCG and those with no CCG (p = 0.017 and p < 0.001 for right and left eyes respectively). We found an association between CCG and ARMD. The presence of CCG in a patient may imply increased risk for the presence of ARMD. In a patient with CCG requiring cataract or corneal surgery, the successful outcome may be compromised by the presence of ARMD.



How to cite this article:
Rao G P, Kaye S B, Agius-Fernandez A. Central corneal endothelial guttae and age-related macular degeneration : is there an association?.Indian J Ophthalmol 1998;46:145-147


How to cite this URL:
Rao G P, Kaye S B, Agius-Fernandez A. Central corneal endothelial guttae and age-related macular degeneration : is there an association?. Indian J Ophthalmol [serial online] 1998 [cited 2021 Apr 21 ];46:145-147
Available from: https://www.ijo.in/text.asp?1998/46/3/145/14959


Full Text

Age-related macular degeneration (ARMD) is a common ocular condition and is a leading cause of registered blindness in both England[1] and the United States.[2] Drusen are a hallmark of ARMD,[3] just as corneal guttae are a hallmark of age-related endothelial degeneration.[4] Both drusen and corneal guttae are seen as excrescences on a membrane (Bruch's and Descemet's), derived from nueroectoderm. Corneal guttae were first described by Duke-Elder as excrescences on Descemet's membrane similar to the excrescences on Bruch's membrane.[5] We report on an association between the presence of central corneal guttae (CCG) and ARMD.

 Materials and Methods



Consecutive patients with central corneal guttae presenting to an ophthalmic accident and emergency department with minor eye complaints such as acute posterior vitreous detachment, migraine, early cataracts, subconjunctival haemorrhages and blepharitis, were recruited. Patients were excluded if they had a history of contact lens wear, intraocular surgery or were using topical medications. Each patient was examined with a slitlamp biomicroscope at xl6 magnification. The distribution, density of guttae, presence or absence of pigment deposition on the endothelial surface and clinically evident corneal edema were recorded. The density of the guttae in the central 5 mm of cornea was graded as mild (50), moderate (50-100), and severe (>100), on an approximate count. Pupils were dilated with tropicamide 1% and phenylephrine 2.5% and the maculae examined with a 78 dioptre non-contact fundus lens. The number of clinically visible drusen were recorded as mild (<10), moderate (10-20) and severe (>20). In addition, any associated pigment epithelial change, abnormal foveal reflex, or neovascular response was also recorded. The first 25 patients were independently evaluated by two trained observers (GPR and AF) using the above grading of mild, moderate and severe (for guttae and drusen). There was complete concordance between the observers so that the remaining 25 patients were evaluated by one observer (GPR) only. For a control group, 51 age-matched patients without evidence of central corneal guttae, presenting to the ophthalmic emergency department for unrelated ocular ailments such as acute posterior vitreous detachment, migraine, early cataracts, subconjunctival haemorrhages and blepharitis (same eligibility criteria as case group), were recruited. The fundi of these patients were similarly evaluated for the presence of drusen or any other sign of ARMD. The data from patients' left and right eyes were analysed separately. Statistical analysis was performed using Fisher exact test and chi-square test.

 Results



Sixty seven patients with CCG were recruited. 17 patients were excluded because of previous intraocular surgery, glaucoma, contact lens wear or uveitis. There were 50 patients (37 females and 13 males) remaining with primary CCG. The age range of these 50 patients was 31-90 years (mean 64 years). 51 subjects were recruited into the control group, age range 29-92 years (mean 67 years). Of these 33 were females and 18 were males. There was no significant difference between the controls and patients in age or sex distribution (p=0.45). The results for patients' right eyes are presented with results for the left eyes in brackets.

 Severity of CCG



Of the 50 patients with CCG, 13 (13) had mild guttae, 13 (13) had moderate guttae and 24 (24) had severe guttae, 7 (7) of whom also had clinically evident corneal thickening and corneal edema. 5 (5) patients had pigment deposition on the endothelium in at least one eye.

 Presence of ARMD



Of the 50 patients with CCG, 23 had bilateral ARMD, 4 had unilateral ARMD (left eye only), leaving 23 with no evidence of ARMD. In the control group, 9 patients had bilateral involvement, 4 had unilateral ARMD and 38 subjects had no ARMD in either eye [Table:1].

 Severity of ARMD



There was a significant difference in the prevalence of ARMD between patients with CCG, 23 (27), and those with no CCG, 11 (11) respectively (p=0.017 for right eye, p<0.001 for left eye). Of the patients with CCG, 10 (10 ) had mild ARMD, 4 (4) moderate disease, 7 (8) had severe ARMD and 2 (5) had disciform scars, compared to 7 (6), 2 (2), 2 (1) and 0 (2) in the control group respectively. There was no significant difference in each level of ARMD between patients with and without CCG (p=0.21, p=0.44), except for those patients with severe ARMD who had an increased prevalence of corneal guttae (p=0.013 and p=0.061, right and left respectively). 2 (5) patients with CCG had evidence of exudative ARMD compared to none (2) in the control group (p=0.24 [0.16]). There was no correlation between the level of severity of CCG and ARMD (p=0.34) [Table:2].

 Discussion



Previous studies have found associations between Fuchs' dystrophy and keratoconus,[6] open angle glaucoma,[7] axial hypermetropia,[8] and cardiovascular disorders.[9] There has been no reported association however, between corneal endothelial and retinal pigment epithelial degeneration. There are striking similarities between corneal endothelium and retinal pigment epithelium in terms of their embryology, barrier function and predisposition to age-related degenerative change. Both are located on basement membranes, that is, Descemet's and Bruch's; have tight junctions between their cells and both have active cell transport systems involving Na-K ATPase and anionic pumps. Both corneal guttae and ARMD are 50% more common in women. We therefore investigated for an association between corneal guttae (corneal aging/degeneration) and retinal drusen (retinal aging/degeneration).

CCG is a manifestation of Fuchs' endothelial dystrophy which is a significant cause of corneal blindness in the United States and United Kingdom[10]accounting for up to 29% of all penetrating keratoplasties.[11] Visual dysfunction occurs when the endothelium decompensates. The reported incidence of central corneal guttae varies between 0.18%-31%[12] and indeed Fuchs stated that 1% of the patients attending his clinic had central corneal guttae.[13] Differing clinical definitions of what constitutes significant guttae may account for the varying incidence and prevalence.

Age-related macular degeneration is a term used to describe a collection of clinically recognizable ocular features that can lead to blindness.[14] It is a leading cause of registered blindness in both England[1] and the United States.[2] Earlier studies have demonstrated that drusen, retinal pigment epithelial detachment or atrophy, subretinal haemorrhage and disciform scars are all manifestations of the same disease and are associated with increasing age and with the development of decreased central visual acuity.[15][16][17] The prevalence of ARMD varies according to the age group studied. The Framingham Eye study[18] provides comprehensive data from standard ophthalmic examinations performed on 2631 persons aged 52-85 years, according to which the total prevalence of ARMD is 8.8%.

Both the corneal endothelium and retinal pigment epithelium are prone to age-related degeneration, some of the signs of which are readily evident on standard ophthalmological examination. We found an association between central corneal endothelial guttae and macular drusen, in that among patients with CCG, there was an increased prevalence of ARMD. The lack of an apparent correlation between the levels of severity of ARMD and CCG may be due to the small number of patients in each subgroup. Whether the corollary exists, that is, of an increased prevalence of CCG in patients with ARMD, remains to be determined. When a patient presents with CCG requiring cataract or corneal surgery, the successful outcome may be compromised by the presence of ARMD, which we have found to be more prevalent in patients with CCG. Although a further prospective evaluation of this association, using specular microscope photos of the endothelium and fundus photos of a larger series is planned, this study was intended as a practical clinical application which is not dependent upon specular microscopy as it is not universally available.

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