The use of epikeratophakia grafts in pediatric monocular aphakia

288

Surv Ophthalmol

26(5) March-April

1982

CURRENT

OPHTHALMOLOGY

1st Annual Duke-Elder Lecture, by Prof. Alan Bird. Trans Ophthalmol Sot U.K. 101:39-45,

198 1

It is encouraging for the clinician interested in retinal disorders that workers in a variety of specialist fields have produced a great deal of new information concerning the inheritance of the disorders contained within retinitis pigmentosa, the functional properties of the diseased retina, and the metabolic characteristics of normal and diseased retinae. It is particularly encouraging that homologues of human disease exist and that there have been major achievements in the search for the pathogenesis of disorders in these animals. It is evident that little of the new knowledge can be applied directly to human disease at present and certainly none has produced any particular clues to possible treatment of disorders within retinitis pigmentosa. Nevertheless, it is clear that the discoveries made by scientists from each discipline are relevant to work in the related fields, and the potential application to clinical ophthalmology is evident. Duke-Elder, by establishing the Institute of Ophthalmofogy, demonstrated his appreciation of the mutual benefits of multidisciplinary research. It is in the interest of clinicians who continue positive inquiry to ensure that new information becoming available from the various disciplines will be applied to human diseases as soon as such applications are possible. With such continued stimulus, it is to be hoped that within the next decade the information will be applicable to the human disorder, and that in time such advances will lead to therapy. (Abstract by C. Hoyt)

Comment Professor Bird, in the 1st Annual Duke-Elder lecture, discusses retinal receptor dystrophies in order to demonstrate the benefit of increased communication between clinicians and basic scientists. He summarizes recent basic science advancement such as the important phagocytic role of the retinal pigment epithelial cell and its abnormal function in the Royal College of Surgeons (RCS) rat. Biochemical studies of cyclic neucleotide function in cell transduction after light exposure are also well presented. These and many other important basic discoveries interest clinicians, but they also frustrate us because they often have little application to the treatment of human retinitis pigmentosa. What can we clinicians do to help bridge the gap between laboratory and patient? Professor Bird offers us some encouragement. Retinitis pigmentosa is actually many separate diseases with different etiologies, and clinicians can help by sub-dividing RP on the basis of morphology, genetic patterns and functional changes. This splitting will result in more pure groups ofpatients to which basic scientists can apply and test their new information. Morphological variants such as sector RP, retinitis punctata albscens, RP with macular edema, and abnormal tapetal reflex in heterozygote females with X-length disease are some possible sub-groups. Careful examination of family members may uncover genetic patterns in the large number of patients whose mode of inheritance is presently unknown. Functional and electrophysiologic testing have revealed a population of patients in which there is loss of rod sensitivity in the presence of well-preserved cone function, and some families in which there is simultaneous degeneration of both rods and cones, This latter data suggests multiple forms of autosomal dominant RP and may allow further sub-divisions. These and other groupings of retinitis pigmentosa patients may allow the clinician and basic scientists to better work together in understanding retinal receptor dystrophies. DENIS M. CARROLL

The Use of Epikeratophakia Grafts in Pediatric Monocular Aphakia, by K.S. Morgan, T.P. Werblin, P.A. Asbell, D.A. Loupe, M.H. Friedlander, and H.E. Kaufman.JPediatr Ophthalmol Strabis 18:23-29, 1981 Epikeratophakia is a form of refractive surgery in which the recipient’s epithelium is removed and a preshaped donor lenticule is sutured to the patient’s cornea. Seventeen patients, ranging in age from 2 months to 6.6 years, received 19 epikeratophakia grafts for the correction of aphakic vision. The correction provided by the graft in combination with vigorous amblyopia therapy has yielded some improvement in vision in the 12 patients with successful grafts. This procedure may be particularly suitable for pediatric aphakic patients because it is extraocular and reversible and may be employed as a secondary procedure or in conjunction with cataract extraction. Only with longer follow-up of these and additional patients can these preliminary results be validated and the risk/

CURRENT benefit

ratio

of this procedure

Epikeratophakia function

289

OPHTHALMOLOGY be assessed.

is currently

in many

of these

in a state

patients;

not the proper treatment prove to be the treatment

of evolution,

however,

and

it will be some

our early visual

for the young patient of choice for visual

acuity

with unilateral rehabilitation

results

time

before

we can evaluate

have convinced

visual

us that conservatism

congenital cataract, and that epikeratophakia of monocular aphakia in children. (Abstract

is may by C.

Hoyt)

Comment Recent both

advances

in the timing

monocular

acuity

and

in pre-verbal

However, clinicians. parent

Although

The technique

error

cataract

and

means

in infancy

or the developing

removal

titer

have

patching

therapy

Moreover,

been

encouraging

techniques

are less than ideal.

eye evolves.

lens technology

have yielded

electrophysiological

to careful

correction

in contact

of epikeratophakia Higher

in the immediate the refractive

advancement

provided

of aphakic

advances

of congenital

Psychophysical

and

aphakic

encouraging,

correction

be readily

fitting

is a promising

plus corrections,

post-operative power

be developed? of congenital

advancement.

However,

up to plus 30, are needed.

period,

in the treatment

Radial Keratotomy: Preliminary Ophthalmic Surg 13:27-35, 1982

which

Despite

these

problems,

and

several

infants

problems

Does the graft

is also the most

cataracts

sensitive

ingrowth,

reviewed

glare,

cornea1

18 primary

pain,

complications

us, should

fluctuating

to hyperopia,

scarring.

addition,

to all

is not easy and

report

with

prevent

of radial

We feel that

the possible

these

additional

be explained

visual

significant

acuity

be a most

as a potential

The two major complications from morning to evening.

which

Determination of the relative (Abstract by C. Hoyt)

safety

future

should of frank

important

encouraging.

Ho\.T

by J. Rowsey and H.D. Balyeat.

namely,

missing

the visual

axis,

inadequate

to evening,

regression

lens fitting

after

be carefully visual

described

to the original

surgery,

endothelial

to the patients

loss from the procedure,

myopic

state,

cell loss, and

preoperatively.

although

In

not observed

by

complication.

have been and

morning

with contact

complications

complications

way of

following surgery, recurrent erosions, stromal overgrowth, of the anterior chamber, induced astigmatism, epithelial

from

difficulty

keratotomy,

visual

Can an cffcctivc

could

is very

this technique

cloudiness

period?

epikeratophakia

this initial

Report of Complications,

incisions around the optimal zone, epithelial defects blood in the incisions, vascular ingrowth, perforation overcorrection

must

available

CKI;IG

We have

in

visual

correction.

Any successful it must

results

of monitoring

is necessary.

need to be addressed. changing

have

means

as the refractive

motivation

recovery

cases.

children

the available

be easily changed

and techniques

binocular

most

efficacy

troublesome

to the patient

of this procedure

therefore

are glare requires

and fluctuating

extensive

further

vision study.

Comment It is apparent

from this report

carefully

controlled

significant

and

protocol disturbing,

and other

in their though

clinical not

studies

reported

investigation catastrophic,

by these authors of radial complications

that

keratotomy. associated

they have adopted

an extremely

This

a number

report with

details

carefully

done

of

radial

keratotomy. Some of the complications observed represent permanent anatomic changes, while others relate to postoperative variability with patient complaints that are at least partly self-limited. Probably the most important mcssagc to be gained is that even with what is described as an extremely careful and well-controlled technique, the refractive outcome of this procedure is variable and unpredictable. Those factors which affect undercorrection and overcorrection can apparently not be determined at the present time. Surgical technique probably are important, but the biological response of the cornea

variables inherent during the healing

in the operative phase may be of